SYSTEM CONFIGURED TO MONITOR A PLURALITY OF ZONES OF AN AIRCRAFT, AND DETECTION METHOD AND SYSTEM

专利摘要:
A system configured to monitor temperature in a plurality of zones of an aircraft includes a fiber optic with first and second ends, first and second connectors, and a first interrogator. The optical fiber includes a plurality of fiber bragg grids arranged on the optical fiber. the first connector is arranged at the first end of the optical fiber and the second connector is arranged at the second end of the optical fiber. The first interrogator is connected to the first connector and includes an optical switch. The optical switch in optical communication with the first fiber optic connector and is configured to selectively block the transmission of optical signal to the optical fiber.
公开号:BR102019002892A2
申请号:R102019002892-0
申请日:2019-02-12
公开日:2019-09-17
发明作者:Mark Sherwood Miller；Robert J. Norris；Lei Liu
申请人:Kidde Technologies, Inc.；
IPC主号:

专利说明:

CONFIGURED SYSTEM TO MONITOR PLANES IN AIRCRAFT AREAS, AND, METHOD AND DETECTION SYSTEM
BACKGROUND OF THE INVENTION [001] This disclosure relates, in general, to the integrity of the aircraft system for overheating and fire detection systems. More particularly, this disclosure relates to monitoring the integrity of the aircraft system using optical signals.
[002] The prior art overheating detection systems typically use eutectic salt technology to detect an overheating event. Eutectic salt involves a central conductor and eutectic salt is surrounded by an outer sheath. A monitoring signal is transmitted along the central conductor and, under normal operating conditions, the eutectic salt acts as an insulator, so that no conduction occurs between the central conductor and the outer sheath. When an overheating event occurs, a portion of the eutectic salt melts and a low impedance path is formed between the central conductor and the outer sheath. The low impedance path is detected by an electronic controller, which generates an overheat alarm signal. When the overheating event has subsided, the eutectic salt will re-solidify and once again isolate the central conductor. Through the use of various salts to create a eutectic mixture, a specific melting point for the salt can be achieved. Thus, different eutectic salts can be used in different areas of the aircraft to provide superheat monitoring at a variety of temperatures. Although eutectic salt technology allows the detection of overheating events, eutectic salt technology only provides a binary indication of whether or not an overheating event has occurred.
Petition 870190014459, of 02/12/2019, p. 84/162 / 62
SUMMARY [003] A system configured to monitor the temperature in a plurality of zones on an aircraft includes an optical fiber with first and second ends, first and second connectors and a first interrogator. The optical fiber includes a plurality of fiber Bragg grids, arranged in the optical fiber. The first connector is disposed on the first end of the optical fiber and the second connector is disposed on the second end of the optical fiber. The first interrogator is connected to the first connector and includes an optical switch. The optical switch in optical communication with the first fiber optic connector and is configured to selectively block the transmission of the optical signal to the optical fiber.
[004] A method of detecting thermal conditions for a plurality of zones in an aircraft system includes the emission, by a first optical transmitter arranged in a first interrogator, of a first optical signal. The first optical signal is distributed over an optical fiber by a first coupler. The first optical signal is selectively blocked by an optical switch on the first interrogator from being transmitted to the optical fiber. A second optical signal is emitted by a second optical transmitter arranged in a second interrogator on the optical fiber. A response signal based on the second optical signal is received from the optical fiber by a second optical receiver on the second interrogator. At least one temperature, based on the response signal, for a portion of the plurality of zones is determined using at least one of the first and second interrogators.
[005] An overheat detection system includes an optical fiber, a first connector, a second connector, a first interrogator, a second interrogator and a controller. The optical fiber includes a first end, a second end and a plurality of fiber Bragg grids arranged in the optical fiber. The first connector is
Petition 870190014459, of 02/12/2019, p. 85/162 / 62 disposed on the first end of the optical fiber and the second connector is disposed on the second end of the optical fiber. Each of the first and second interrogators includes an optical transmitter, a detector and an optical switch. The optical transmitter is configured to emit an optical signal. The first detector is configured to receive an optical response from the optical fiber. The optical switch is in optical communication with the optical fiber and is configured to selectively block the transmission between the optical fiber and the optical transmitter and the detector to prevent the detector from the first interrogator and the second interrogator from receiving a signal from the optical transmitter of the other between the first interrogator and the second interrogator.
BRIEF DESCRIPTION OF THE FIGURES [006] FIG. 1 is a schematic view of an overheat detection system architecture for monitoring multiple zones.
[007] FIG. 2 is a flow diagram that illustrates examples of operations to provide detection of overheating on an aircraft using optical signals.
[008] FIG. 3 is a flow diagram illustrating examples of operations using optical signals to provide health monitoring for an aircraft.
[009] FIG. 4A is a simplified block diagram of a fiber optic event detection system with a replaceable single-line unit including Bragg grids in superheat fiber and Bragg grids in temperature fiber.
[0010] FIG. 4B is a simplified block diagram of a fiber optic event detection system with two replaceable line units including Bragg grids in superheat fiber and Bragg grids in temperature fiber.
Petition 870190014459, of 02/12/2019, p. 86/162 / 62 [0011] FIG. 5A is a block diagram of a multi-channel interrogator with optical switches positioned downstream of the couplers.
[0012] FIG. 5B is a block diagram of a multi-channel interrogator with optical switches positioned upstream of the couplers.
[0013] FIG. 6 is a block diagram of a multi-channel interrogator with a 1xN optical switch.
[0014] FIG. 7 is a simplified block diagram of a fiber optic event detection system with a replaceable single-line unit including overheating fiber Bragg grids, temperature fiber Bragg grids and timing marker fiber Bragg grids .
[0015] FIG. 8 is a graph representing a response signal from the overheat detection system and a series of sample points.
[0016] FIG. 9A is a simplified block diagram of a fiber optic event detection system with a replaceable single-line unit including overheating fiber Bragg grids, temperature fiber Bragg grids, timing marker fiber Bragg grids and grids Bragg fibers in calibration fiber arranged in a first pattern.
[0017] FIG. 9B is a simplified block diagram of a fiber optic event detection system with a replaceable single-line unit including overheating fiber Bragg grids, temperature fiber Bragg grids and timing marker fiber Bragg grids and Bragg grids in calibration fiber in a second pattern.
DETAILED DESCRIPTION [0018] FIG. 1 is a schematic diagram of the detection system
Petition 870190014459, of 02/12/2019, p. 87/162 / 62 of superheat 10 for aircraft 12. Aircraft 12 includes ZaZj zones and avionics controller 14. System of overheat detection 10 includes interrogators 16a-16b and optical fibers 18a-18c. Interrogator 16a includes optical transmitter 20a, detector 22a and computer-readable memory 24a. Interrogator 16b includes optical transmitter 20b, detector 22b and computer readable memory 24b. Optical fibers 18a-18c include the first ends 28a-28c and the second ends 30a-30c.
[0019] The superheat detection system 10 is a system for detecting specific overheating events and / or temperature values over various areas of the aircraft 12. The aircraft 12 is an airplane, helicopter or other machine capable of flying. Za - Zj zones can include any one or more locations on aircraft 12 where overheat detection is desired. For example, Za-Zj zones may include air bleed ducts, cross-transmission air ducts, wheel wells, wing boxes, air conditioning (A / C) packages, antifreeze systems, nitrogen generation systems or any other area where temperature detection is desirable. While aircraft 12 is described as including ten zones, it should be understood that aircraft 12 can be divided into as many zones as desired. The aircraft 12 can be divided into zones in any desired manner; for example, aircraft 12 can be divided into zones based on the superheat temperature for the components located in that zone or based on the type of system. Each Za-Zj zone on aircraft 12 can have a different alarm setpoint. For example, when the temperature in zone Za is the same as the temperature in zone Zb, an overheat alarm can be triggered for zone Zb, but not for zone Za.
[0020] The avionics controller 14 is a digital computer and can include one or more electronic control devices. In a modality
Petition 870190014459, of 02/12/2019, p. 88/162 / 62 non-limiting, the avionics controller 14 can be part of the first or second interrogator 16a or 16b. In another non-limiting mode, the avionics controller 14 can be omitted from the superheat detection system 10 and so that the first and / or second interrogators 16a and 16b will determine all information, including the configuration of the zone, the number of zones , temperature limit, overheat detection and other features of an avionics controller. In such a non-limiting mode, the first and second interrogators 16a and 16b are connected to a communication channel in order to communicate with each other. Each of interrogators 16a and 16b can be a microprocessor, a microcontroller, application specific integrated circuits (ASIC), a digital signal processor (DSP), a field programmable port arrangement (FPGA) or other discrete or integrated logic circuit. equivalent. In this and other non-limiting modalities discussed in this document, interrogators 16a and 16b are interrogators of fiber Bragg grids (FBG) (see, for example, FIGURES 2-9B). The interrogators 16a and 16b are substantially similar and, for ease of discussion, the interrogator 16a with the optical transmitter 20a, the detector 22a and the computer-readable memory 24a will be discussed in more detail.
[0021] Optical fibers 18a, 18b and 18c are optical fiber cables configured to communicate an optical signal. The optical fibers 18a, 18b and 18c are substantially similar and, for ease of discussion, the optical fibers 18a with the first end 28a and the second end 30a will be discussed in more detail. Optical fiber 18a is illustrated as including the first end 28a and the second end 30a. It should be understood that while optical fiber 18a is illustrated as including a single optical fiber cable, each of the optical fibers 18a-18c can include one or more optical fiber cables. In other non-limiting embodiments, optical fibers 18a-18c may include one or more replaceable units in
Petition 870190014459, of 02/12/2019, p. 89/162 / 62 line (LRUs) that divide optical fibers 18a-18c into separate, but connectable, optical fiber segments. Throughout this disclosure, the term “channel” is synonymous with optical fiber and, as such, the two terms can be used interchangeably to refer to the same respective element.
[0022] The optical transmitter 20a can be any suitable optical source to provide an optical signal. In a non-limiting mode, the optical transmitter 20a can be a light emitting diode or a laser. It should also be understood that the optical transmitter 20a can be configured to provide the optical signal in any suitable manner, such as through a single pulse at a fixed wavelength, a tunable wavelength, a broadband signal and / or a tunable pulse. Detector 22a is a receiver configured to receive an optical signal. For example, detector 22a can be a photodiode, a set of photodiodes, a phototransistor, a circulator or any other suitable optical receiving device. Although interrogator 16a is described as including a single detector 22a, it should be understood that interrogator 16a can include multiple optical receivers to receive the optical signal from different optical fibers, different optical fiber cables and / or different ends of the optical fiber cables .
[0023] Computer-readable memory 24a can be configured to store electronic component information during and after aircraft operation 12. In a non-limiting mode, computer-readable memory 24a can be described as a computer-readable storage medium . In a non-limiting embodiment, a computer-readable storage medium may include a non-transitory medium. The term "non-transitory" may indicate that the storage medium is not incorporated into a carrier wave or a propagated signal. In a non-limiting mode, a non-transitory storage medium can store data that can, over time
Petition 870190014459, of 02/12/2019, p. 90/162 / 62 of the time, change (for example, in RAM or cache). In a non-limiting embodiment, computer-readable memory 24a may include temporary memory, which means that a primary purpose of computer-readable memory is not long-term storage. In a non-limiting embodiment, computer-readable memory 24a can be described as volatile memory, meaning that computer-readable memory 24a does not keep stored content when electricity is removed. In a non-limiting embodiment, examples of volatile memories can include random access memories (RAM), dynamic random access memories (DRAM), static random access memories (SRAM) and other forms of volatile memories. Couplers 26a and 26b are optical devices with one or more optical inputs and one or more optical outputs and which are capable of dividing an optical signal into multiple channels. The first end 28a and the second end 30a are opposite ends of the optical fiber 18a.
[0024] The superheat detection system 10 is arranged inside and along several zones Za-Zj of the aircraft 12. In this non-limiting mode, the optical fiber 18a passes through the Zb-Zd zones, the optical fiber 18ab passes through the Za zones and Ze-Zg and the 18ac optical fiber passes through the Zh-Zj zones. As such, each optical fiber 18a-18c traverses and gathers information relating to multiple aircraft zones 12. The avionics controller 14 is mounted inside the aircraft 12 and is electrically connected to interrogators 16a and 16b. The interrogator 16a is connected to the avionics controller 14 to communicate information to the avionics controller 14. The interrogator 16a is connected to the optical transmitter 20a to control the transmission of an optical signal from the optical transmitter 20a to the fiber optic cable 18a. Interrogator 16a is also connected to detector 22a to analyze the signals received by detector 22a.
[0025] Optical fibers 18a-18c are substantially similar and,
Petition 870190014459, of 02/12/2019, p. 91/162 / 62 for the sake of clarity and ease of discussion, optical fiber 18a will be discussed in more detail. Optical fiber 18a passes through each of the ZbZd zones and is connected to interrogator 16a and interrogator 16b. The optical fiber 18a is in optical communication with detector 22a of interrogator 16a and detector 22b of interrogator 16b. The optical fiber 18a is connected to interrogator 16a at the first end 28a and interrogator 16b at the second end 30a. Optical fiber 18b is connected to interrogator 16a at the first end 28b and interrogator 16b at the second end 30b. Optical fiber 18c is connected to interrogator 16a at the first end 28c and interrogator 16b at the second end 30c. Interrogators 16a and 16b are connected to the avionics controller 14 to communicate with other systems within the aircraft 12.
[0026] The optical transmitter 20a is mounted inside the interrogator
16a and is in optical communication with optical fiber 18a via coupler 26a. The detector 22a is mounted inside the interrogator 16a and is in optical communication with the optical fiber 18a through the coupler 26a. Computer-readable memory 24a is mounted within interrogator 16a and is in communication with optical transmitter 20a and detector 22a. Coupler 26a is mounted within interrogator 16a and is in optical communication with optical transmitter 20a, detector 22a and optical fiber 18a. The first end 28a of the optical fiber 18a is connected to the interrogator 16a and is in optical communication with the coupler 26a and the second end 30a of the optical fiber 18a. The second end 30a of the optical fiber 18a is connected to the interrogator 16b and is in optical communication with the coupler 26b and with the first end 28a of the optical fiber 18a.
[0027] The superheat detection system 10 can detect a temperature or voltage at any location or at multiple locations along the optical fiber 18a. Since the temperature can be detected at any location or at multiple locations along the optical fiber 18a, a profile
Petition 870190014459, of 02/12/2019, p. 92/162 / 62 temperature can be developed for optical fiber lengths 18a, 18b and 18c and, as such, a temperature profile can be developed for each Za-Zj zone. The superheat detection system 10 can also provide location information relative to a specific location within each Za-Zj zone in which an event occurs. The temperature profile for each Za-Zj zone can then be compared with a maximum allowed temperature profile, which can include a single temperature for the entire Za-Zj zone or multiple temperatures at variable locations in each Za-Zj zone. It should be understood that communications to the overheat detection system 10 can be made using any combination of wired, wireless or optical communications.
[0028] Aircraft 12 can also include a central computer for the overheat detection system that communicates with various overheat detection systems on aircraft 12 and the central computer for the overheat detection system can report any state of overheating of any system for overheating the cab. The avionics controller 14 communicates information from interrogators 16a and 16b to other systems within the aircraft 12.
[0029] Interrogators 16a-16b can communicate with avionics controller 14 and avionics controller 14 can consolidate information received from interrogators 16a-16b and provide information to the cockpit, provide information to maintenance personnel and / or store the information to generate the trend data. While interrogators 16a-16b are described as communicating with the avionics controller 14, it should be understood that interrogators 16a16b can communicate directly with cockpit personnel or are on the ground, they can store information to generate flight data.
Petition 870190014459, of 02/12/2019, p. 93/162 / 62 trend and / or can communicate with a central superheat computer. It should be understood that all communications to the superheat detection system 10 can be made using wired, wireless or optical communications or some combination of these methods.
[0030] While interrogator 16a is described as communicating with the avionics controller 14, interrogator 16a can communicate with aircraft 12 and maintenance personnel in any appropriate manner. Interrogators 16a can also communicate directly with the aircraft cabin 12 to provide overheating or fire detection alerts or to indicate that maintenance is required. Interrogator 16a can also communicate temperature data to other computers in the system, which can report a state of overheating to the cockpit. Interrogators 16a can further communicate with the avionics controller 14 to communicate temperature data to the avionics controller 14 using a wired or wireless connection.
[0031] The interrogator 16a can be configured to control the optical transmitter 20a to control the transmission of an optical signal through the optical fiber 18a. Interrogator 16a can also be configured to receive an optical signal from detector 22a and to analyze the optical signal received at detector 22a. Interrogator 16a receives information regarding the optical signal from detector 22a. Variations in the optical signals analyzed by interrogator 16a allow interrogator 16a to determine the temperature within the Za-Zj zones and to determine a location of the temperature variation within the Za-Zj zones. Variations in optical signals also allow interrogator 16a to determine the voltage experienced at various locations along optical fiber 18a. Interrogator 16a is configured to determine whether an overheat event has occurred, the zone in which the overheat event occurred, and whether the overheat event is at or
Petition 870190014459, of 02/12/2019, p. 94/162 / 62 above the alarm setpoint for that zone. The interrogator 16a, therefore, identifies the length and alarm setpoint of the optical fiber 18a in each Za-Zj zone and the order in which the optical fiber 18a passes through each Za-Zj zone.
[0032] Interrogator 16a can also generate trend data to facilitate the monitoring of aircraft 12 health. Trend data can include data on temperature trends, deformation trends or both. Trend data can be stored in the memory of interrogators 24a of an interrogator 16a or any other suitable storage medium in any other suitable location, such as the memory of the avionics controller 14. It should be understood that the data can be monitored in real time. In a non-limiting mode, interrogator 16a can communicate with a dedicated integrity monitoring system to monitor temperature data in real time. The stored trend data provides statistical and historical data for the temperature, voltage (or both) experienced in all Za-Zj zones. Temperature trend data can be stored and monitored by maintenance personnel. As such, temperature trend data allows maintenance personnel to determine the location of the progressive temperature over time.
[0033] It should also be understood that interrogator 16a can generate the location of a single temperature variation, voltage variation or both. The generation of the progressive temperature rise locations allows for preventive and direct maintenance before a failure occurs. For example, the temperature trend in the right wheel well can be monitored to generate trend data. Trend data can show that a tire inside the right wheel well exceeds normal operating temperatures without reaching the alarm set point. In this case, a
Petition 870190014459, of 02/12/2019, p. 95/162 / 62 overheating event does not occur; however, the temperature trend data informs maintenance personnel that the tire may be close to failing or that the tire may have low air pressure and that a maintenance action is required. Similar to temperature monitoring, voltage trend data can be stored and areas of increased stress can be located. In a non-limiting mode, the bleed air pressure that passes through a bleed duct can transmit a tension in the bleed duct wall. The voltage level and the location of the voltage can be detected by interrogators 16a who analyze the information received from the optical signals. The voltage information can then be communicated to the ground crew and used to investigate the location of the increased voltage to determine any maintenance actions that must be performed.
[0034] Optical fibers 18a, 18b and 18c are configured to transmit and / or communicate an optical signal. As will be discussed with reference to other figures, the FBG sensors arranged along the optical fibers 18a, 18b and 18c are used to determine the linear expansion of the optical fibers 18a, 18b and 18c during the operation of the aircraft 12. As such, the fibers optics 18a, 18b and 18c can provide temperature and / or voltage detection in all Za-Zj zones. The optical transmitter 20a provides an optical signal to the optical fibers 18a, 18b and 18c. The optical transmitter 20a is configured to provide an optical signal to the first end 28a of the optical fiber 18a. It should be understood that a single optical transmitter 20a can provide the same optical signal for each of the optical fibers 18 a, 18b and 18c.
[0035] The detector 22a is configured to receive optical reflection signals excited by the optical transmitter 20a or optical transmission signals excited by the optical transmitter 20b. Where the optical transmitter 20a provides the optical signal through the first end 28a, the optical signal travels
Petition 870190014459, of 02/12/2019, p. 96/162 / 62 through optical fiber 18a and is reflected back to the first end 28a and received by detector 22a. The detector 22a communicates information regarding the first portion of the optical signal, the second portion of the optical signal, or both, to the interrogator 16a. In some non-limiting examples, computer-readable memory 24a can be used to store program instructions for execution by one or more interrogator processors 16. For example, computer-readable memory 24a can be used by software or applications run to store information temporarily while the program is running.
[0036] Coupler 26a divides an optical signal received from optical transmitter 20a into optical signals for each of the optical fibers 18a, 18b and 18c. In this non-limiting mode, coupler 26a includes a 2x3 configuration (for example, 2 inputs and 3 outputs). In other non-limiting embodiments, coupler 26a can include one or more couplers including NxM configurations, where N and M can be any number of inputs and outputs. The first end 28a is configured to communicate an optical signal from interrogator 16a to optical fiber 18a and to communicate an optical signal from optical fiber 18a to interrogator 16a. The second end 30a is configured to communicate an optical signal from the optical fiber 18a to the interrogator 16b and to communicate an optical signal from the interrogator 16b to the optical fiber 18a.
[0037] Different systems within 12 aircraft require monitoring of overheat detection and each system can be divided into multiple zones. For example, a bleed air duct on aircraft 12 may include multiple zones with a single optical fiber that extends through all areas of the bleed air duct. Each system can thus be divided into multiple zones and can include a dedicated interrogator and fiber optics. It should be understood, however, that the aircraft 12 can be divided into zones in any desired manner.
Petition 870190014459, of 02/12/2019, p. 97/162 / 62 [0038] The first end 28a of the optical fiber 18a receives an optical signal from the optical transmitter 20a located inside the interrogator 16a, the optical fiber 18a transmits the optical signal through the optical fiber 18a to the second end 30a and the second end 30a transmits the optical signal to detector 22b located within interrogator 16b. Interrogator 16b analyzes the signal received by detector 22a to determine the temperature in the Zb-Zd zones. Each Zb-Zd zone can have a different alarm setpoint, as the temperature resistance of each zone can be different. As such, interrogator 16b analyzes the information received to determine the temperature in each zone. In addition to determining the temperature in the ZbZd zones, the interrogator 16b can analyze the information received from the optical fiber 18a to determine the voltage experienced in each Zb-Zd zone. Interrogator 16b can thus monitor temperature, voltage or both, within Zb-Zd zones. While optical fiber 18a is described as being connected to interrogators 16a and 16b, it should be understood that optical fiber 18a can be arranged in a single termination configuration so that only one of the first end 28a and second end 30a is connected to the interrogator 16a. For example, in the single-end configuration, where the first end 28a is connected to interrogator 16a, interrogator 16a can provide an optical signal to the first end 28a of optical fiber 18a and can interpret the signal that is reflected back through the first end 28a.
[0039] Additional examples of fiber optic overheat detection systems can be found in United States Patent Application co-pending serial number 15 / 600,100 filed on May 19, 2017, which is incorporated into this document by reference in your totality. With continued reference to FIG. 1, FIGS. 2-3 are flow diagrams that illustrate examples of operations to determine the occurrence and location of an overheating event. For the sake of clarity and
Petition 870190014459, of 02/12/2019, p. 98/162 / 62 ease of discussion, the sample operations are described below within the context of the overheat detection system 10. The non-limiting modalities discussed in this document can be for any FBG detection system, regardless of what is being measured (ie, temperature or others).
[0040] FIG. 2 is a flow diagram that illustrates examples of operations to provide detection of overheating on an aircraft using optical signals. In step 32, an optical signal is supplied to one or more fiber optic cables, such as optical fibers 18a-18c. For example, the optical transmitter 20a can provide an optical signal to the optical fiber 18a through the first end 28. In step 34, an optical response signal is received by the optical fiber detector 22a 18a. For example, detector 22a can receive the optical response signal from optical fiber 18a and detector 22a can provide the optical response signal to interrogator 16a. In step 36, the optical response signal is analyzed to determine temperature, voltage, or both along optical fiber 18a. For example, interrogator 16a can analyze the optical response signal received from detector 22a to determine the actual temperature and / or deformation at various locations along the optical fiber 18a. Interrogator 16a can use any suitable method to analyze the optical response, such as the methods discussed below. It should be understood that optical fiber 18a can detect a temperature anywhere along optical fiber 18a and the optical signal can be interrogated to determine the precise location at which the temperature change occurs. As such, the temperature data analyzed by interrogator 16a can include information to determine a temperature at a single location within a zone, a temperature at multiple locations across a zone, a temperature profile for a zone or any other information from temperature for the zone. In step 38, the temperature data and / or voltage data generated in step 36 are compared with a limit. Where data from
Petition 870190014459, of 02/12/2019, p. 99/162 / 62 temperature and / or voltage data indicate that the temperature and / or voltage are below the threshold level, the operation returns to step 32. Where the temperature data and / or voltage data indicate that the temperature and / or voltage is above the limit level, the operation proceeds to step 40 and the existence of the overheat condition is indicated and communicated to the cockpit and / or ground personnel.
[0041] FIG. 3 is a flow diagram illustrating examples of operations using optical signals to provide health monitoring for an aircraft. In step 42, an optical signal is supplied to one or more fiber optic cables, such as optical fibers 18a-18c. In step 44, an optical response signal is received by the optical fiber 18a. In step 46, the optical response signal is analyzed to determine the temperature, voltage or both experienced across the optical fiber 18a. In step 48, temperature data, strain data, or both are stored in memory. For example, temperature data can be stored in memory 24a of interrogator 16a. In step 50, trends are developed for stored temperature and / or voltage data and trends are monitored for any patterns that indicate that a maintenance action is required.
[0042] By using optical fiber 18a to determine the existence of an overheating event, the prior art eutectic salt sensors and, consequently, the electrical connections associated with the eutectic salt sensors can be eliminated from the aircraft 12. The sensors of eutectic salt from the prior art detects whether or not an overheating event is occurring and, as such, provides a binary response. Unlike the prior art eutectic sensors, optical fiber 18a detects any changes in temperature and the location of the temperature change, and not only if a temperature set point has been exceeded. As such, interrogator 16a can collect trend data for each zone
Petition 870190014459, of 02/12/2019, p. 100/162 / 62 that optical fiber 18a extends, as data is continuously collected by interrogator 16a. Temperature trend data provides maintenance personnel with information on the overall health of each Za - Zj zone. The provision of trend data allows maintenance to be performed in specific and relevant locations and only when necessary, thus reducing aircraft downtime 12. In addition to providing temperature trend data, optical fiber 18a is capable of detecting voltage within each Za-Zj zone, unlike the prior art eutectic salt sensors, which are sensitive only to temperature. The use of optical fiber 18a thus provides additional structural information for maintenance personnel.
[0043] The monitoring of the temperature trend, the voltage trend or both within the Za - Zj zones provides information about the general integrity of the zone being monitored and the system in which the zone is located. Trend data can be used to facilitate preventive maintenance. In addition, monitoring trend data allows maintenance actions to be scheduled at convenient times and locations, rather than waiting until a real failure occurs, which can lead to boarding delays, canceled flights or crew action on flight. In addition, monitoring the actual temperature in Za - Zj zones allows the superheat detection system 10 to provide fire monitoring in addition to overheating detection. A sudden rise in temperature may indicate a fire rather than an overheating event. For example, a fire in a wheel well would cause a sudden and dramatic increase in the temperature of the wheel well and this sudden and dramatic increase would be perceived by the portion of the fiber optic cable that passes through the zone that includes the wheel well. Interrogator 16a can analyze the data provided from the zone that includes the wheel well to determine the existence of the fire event and to report the existence
Petition 870190014459, of 02/12/2019, p. 101/162 / 62 from the fire event to the cockpit, to a fire suppression system or to any other appropriate or personal system.
[0044] A variety of fiber optic cables and operating principles can be used to determine the existence of an overheating event. For example, the superheat detection system 10 can use a single fiber optic cable, dual fiber optic cables and fiber optic cables, including FBGs. In addition, fiber optic cables can be arranged in a single circuit configuration, a double circuit configuration or any other suitable configuration. An optical signal is initially supplied to optical fiber 18a and as the optical signal travels through optical fiber 18a, most of the optical signal travels from the first end 28a to the second end 30a, but a fraction of the optical signal is backscattered in the direction of the first end 28a. Interrogators 16a and 16b can analyze the portion of the optical signal received through the second end 30, the portion of the optical signal being backscattered through the first end 28a or a combination of both to determine the temperature and / or voltage information. As such, it should be further understood that the optical fiber 18a can be arranged in a single-ended configuration, where one of the first 28a or second 30a ends is connected to one of interrogator 16a or interrogator 16b. In a single-end configuration, interrogator 16a can deliver the optical signal through one end of the optical fiber 18a and can interpret the part of the backscattered optical signal through the end of the optical fiber 18a connected to the interrogator 16b.
[0045] Where optical fiber 18a includes FBGs, interrogator 16a can analyze the optical signal using a variety of principles, including Wavelength Division Multiplexing (WDM), Time Division Multiplexing (TDM) and / or a combination WDM and TDM (WDM / TDM), among others. An FBG is a reflector distributed within the cable
Petition 870190014459, of 02/12/2019, p. 102/162 / 62 of optical fiber that is configured to reflect a certain wavelength of light and allows all other wavelengths to pass. As such, FBGs function as specific wavelength reflectors. The specific wavelength reflected by a specific FBG is the Bragg wavelength. In the superheat detection system 10, the optical fiber 18a includes several FBGs within the optical fiber 18a. Different FBGs can be arranged within different zones of the aircraft. As such, the Bragg wavelength associated with each zone differs from the Bragg wavelength associated with the other zones. Since interrogator 16a can identify which Bragg wavelength is associated with which zone, interrogator 16a can determine the distance of each FBG based on the time it takes for the Bragg wavelength to travel from the first end 28a to the FBG and back to the first end 28a. The Bragg wavelength is sensitive to voltage and temperature. Changes in voltage and temperature result in a deviation in the Bragg wavelength, which can be detected by interrogator 16a and used to determine the change in voltage and / or temperature.
[0046] In WDM, interrogator 16a provides an optical signal to the first end 28a of optical fiber 18a with optical transmitter 20a. The optical transmitter 20a can be a tunable wavelength scanned laser. The wavelength of the optical transmitter 20a is scanned over a predefined range. The wavelength of the optical signal to be transmitted at any point in time is known. The Bragg wavelengths are received at the first end 28a of the optical fiber 18a by the detector 22a and the interrogator 16a correlates or maps the changes in the Bragg wavelengths in intensity as a function of time. A change in Bragg's wavelength indicates a change in temperature and / or voltage and tracking changes in Bragg's wavelength allows interrogator 16a
Petition 870190014459, of 02/12/2019, p. 103/162 / 62 determine the temperature in each FBG within each zone Z ₁ -Z _n .
[0047] In TDM, the optical transmitter 20a is a broadband laser light source, so that multiple wavelengths are transmitted via optical fiber 18a. Each FBG is configured to reflect a specific Bragg wavelength. Interrogator 16a monitors the time required for each Bragg wavelength to return to the first end 28a. The time required for each Bragg wavelength to return to the first end 28a indicates the location of each fiber optic FBG 18a. Having established the location of each FBG on optical fiber 18a, optical transmitter 20a provides pulses through optical fiber 18a. The wavelength of each pulse can be determined when the reflected pulse arrives at interrogator 16a. Changes in wavelength are detected and converted to intensity versus time, thus allowing interrogator 16a to determine the temperature at the location of each FBG on optical fiber 18a.
[0048] In WDM / TDM, interrogator 16a provides optical signals through optical fiber 18a using an adjustable wavelength scanned laser and a broadband laser light source. Similar to WDM and TDM, in WDM / TDM, the reflected Bragg wavelengths are monitored for any changes in wavelengths. Changes in wavelengths are converted into intensity versus time, thus allowing interrogator 16a to determine the temperature at the location of each FBG. WDM / TDM reduces the loss of any signal in the FBG and the total wavelength that must be scanned to interrogate the Bragg wavelength is similarly reduced. Temperature changes cause the Bragg wavelength to change and the shift in the Bragg wavelength is analyzed by interrogator 16a to determine a temperature change and, therefore, whether an overheating event has occurred. In addition, the location of the
Petition 870190014459, of 02/12/2019, p. 104/162 / 62 overheating event is detected by interrogator 16a based on the displacement at a given Bragg wavelength, as the location of an FBG associated with a Bragg wavelength is known. [0049] In some non-limiting modalities, interrogator 16a can analyze the optical signal using any suitable method, including Optical Time Domain Reflectometry (OTDR), COFDR, Brillouin Optical Frequency Domain Analysis (BOFDA), Domain Analysis of Optical Brillouin Time (BOTDA), Incoherent Optical Frequency Domain Reflectometry (IOFDR) using a Scan Frequency Methodology and IOFDR using a Step Frequency Methodology. Examples of such methods can be found in the United States Patent Application co-pending serial number 15 / 600,100 filed on May 19, 2017, which is incorporated into this document by reference in its entirety.
[0050] The existing sensors and overheating detection systems are based on a technology that uses eutectic salts as a temperature switch to indicate when a leak occurs in the system, for example, a bleed air system. The eutectic salt sensor technology, however, is meeting its capacity limitations in terms of manufacturing capacity, overheat detection accuracy, overheat location and fault location. In addition, rapid changes have been observed in the industry requirements for overheating detection systems, for example, the aeronautical industry, which, due to the reduced tolerance of compounds at increased room temperature, require rapid detection of relatively small overheating events. The result is the need to look for an alternative technical solution to meet this need.
[0051] A candidate for the next generation superheat detection system is based on distributed temperature detection
Petition 870190014459, of 02/12/2019, p. 105/162 / 62 mentioned above using FBGs. An FBG is an optical sensor that consists of a periodic index of refractive changes within the core of a single-mode optical fiber. The FBG acts as a selective wavelength mirror, reflecting only in a narrow wavelength band, which varies according to the voltage and / or temperature experienced by the optical fiber. Measurements are made by determining the amount of displacement of the central wavelength of the reflected signal.
[0052] As discussed above, an interrogator connected to the optical fiber with FBGs will use a scanned wavelength laser or a broadband source with a spectrum analyzer to generate a signal representing a spectrum returned from the FBG detection matrix. For a single FBG, the return spectrum is a narrow Gaussian-shaped return, the central wavelength of which is dependent on the temperature and voltage of the location in the optical fiber where the single FBG is located. A significant advantage of a system involving FBGs is that there are two options for multiplexing large sensor arrays in a single interrogator: wavelength division multiplexing (WDM); and time division multiplexing (TDM).
[0053] For a WDM system, FBGs can be manufactured in well-defined wavelength zones, where each zone is independent. The return spectrum for a WDM-type system has characteristic Gaussian returns spaced across the spectrum, each return representing a single FBG. A limit or restriction of such a system is the amount of spectrum that can be interrogated and the amount of spectral movement expected during the measurement for each FBG. In some non-limiting modes, the systems can scan a laser over 40nm with 16 defined zones, each of which can monitor a sensor over a temperature range of 200 ° C. The relative movement of the center of the wavelength for an FBG in relation to temperature is
Petition 870190014459, of 02/12/2019, p. 106/162 / 62 typically around 10 pm/°C.
[0054] For a TDM system, the signal source is pulsed with very short pulses. The concept is to differentiate single FBGs on a single optical fiber at the moment the reflected optical signal takes to return from each FBG. Representative time values are about 1 nanosecond to 10 centimeters in length of optical fiber. Thus, to measure FBG sensors spaced 0.5 meters across an optical fiber, the pulse of the optical signal must not be greater than 5 nanoseconds in width. To ensure that the reflected optical return signal represents only one FBG sensor at any given time, a pulse around half the width of 5 nanoseconds would be beneficial, for example, a ratio of 0.5 nanoseconds per 10 centimeters in length. fiber. For an overheat application, the two-sided interrogation can be used to monitor multiple independent channels, each with a number of separate wavelength zones and including a specific wavelength zone that will use TDM to provide near-temperature measurements distributed. The representation of this concept is represented in FIGS. 4A and 4B.
Method for Isolating Individual Channels in a Multi-Channel Fiber Optic Event Detection System (Figures 4A - 6) [0055] The following portions of the disclosure refer to and discuss a method for isolating individual channels in an event detection system multi-channel optical fiber.
[0056] FIG. 4A is a simplified block diagram of the first
LRU 52a (inline replaceable unit), second LRU 52b and third LRU 52c and shows the first interrogator 16a, the second interrogator 16b and the first, second and third LRUs 52a, 52b and 52c, respectively, including: optical fibers 18a ₁ 18a ₂ and 18a ₃ ; first connectors 54a, 54b and 54c; second connectors 56a, 56b and 56c; superheat FBG sensors 58a, 58b and
Petition 870190014459, of 02/12/2019, p. 107/162 / 62
58c; FBG temperature sensors 60a, 60b and 60c; and breaks 62a, 62b and 62c in the optical fibers 18a, 18b and 18c). The first, second and third LRUs 52a, 52b and 52c and their components are substantially similar and, for the sake of clarity and ease of discussion, the first LRU 52a will be discussed in more detail. In the non-limiting embodiment shown in FIG. 4A, breaks 62a, 62b and 62c are shown to be present in the first LRU 52a, the second LRU 52b and the third LRU 52c. However, breaks 62a, 62b and 62c are typically not included in the first LRU 52a, the second LRU 52b and the third LRU 52c, but it should be understood that breaks 62a, 62b and 62c represent potential physical conditions of the first LRU 52a, second LRU 52b and third LRU 52c that can form and / or be present.
[0057] The first LRU 52a is a replaceable discrete line unit that is part of the superheat detection system 10 (shown in FIG.1). The first LRU 52a includes the first connector 54a, the second connector 56a and the optical fiber 18a1. The first connector 54a and the second connector 56a are connecting devices. The superheat FBG sensors 58a are fiber Bragg grid optical sensors (fiber Bragg grating, “FBG”) configured to detect an overheating condition of the fiber optic 18a1. In this non-limiting mode, three overheating FBG sensors 58a are shown positioned between consecutive temperature FBG sensors 60a. In other embodiments, there may be more or less than three consecutive overheating FBG sensors 58a positioned between consecutive temperature FBG sensors 60a, such as, for example, twenty overheating FBG sensors 58a.
[0058] FBG temperature sensors 60a are optical sensors
FBG configured to detect an optical fiber temperature 18a1. In other non-limiting modalities, the quantities of FBG sensors of
Petition 870190014459, of 02/12/2019, p. 108/162 / 62 superheat 58a and FBG temperature sensors 60a included in the first LRU 52a can be greater or less than the quantities shown in FIG. 4A and 4B. In this non-limiting modality, approximately uniform distances are shown between adjacent FBGs of the same type along optical fiber 18a ₁ . However, non-uniform distances can also be incorporated. The break 62a is a break or damaged portion in the optical fiber 18a1. In this non-limiting embodiment, the break 62a represents a potential physical state of a portion of optical fiber 18a1. For example, the typical operational state of optical fiber 18a1 does not include break 62a (and also for optical fibers 18a ₂ and 18a ₃ ).
[0059] The first LRU 52a is fixed and connected to the first and second interrogators 16a and 16b through the first and second connectors 54a and 56a. The first connector 54a is mounted on an optical fiber end 18a ₁ and is connected to the first interrogator 16a. The second connector 56a is mounted on the opposite end of the optical fiber 18a1 from the first connector 54a and is connected to the second interrogator 16b. Superheat FBG sensors 58a and temperature FBG sensors 60a are arranged in and along portions of optical fiber 18a1. The break 62a can be arranged in a fiber optic portion 18a1.
[0060] In this non-limiting mode, the first interrogator 16a functions as the primary or primary interrogator, with the second interrogator 16b functioning as the secondary interrogator. For example, second interrogator 16b will typically occupy a ready state, but will not actively interrogate optical fiber 18a1, unless it is necessary to do system testing or in case one of the FBGs breaks and the entire length of the fiber optics 18a1 can no longer be interrogated from one end. In a rupture event (for example, rupture formation 62a), the second interrogator 16b is activated to inspect the broken optical fiber 18a1 on the opposite side of the rupture 62a from the first interrogator
Petition 870190014459, of 02/12/2019, p. 109/162 / 62
16th.
[0061] The first LRU 52a provides a replaceable fiber optic segment for use in the superheat detection system 10. The first connector 54a fixes and connects the optical fiber 18a ₁ to the first interrogator 16a. The second connector 56a fixes and connects optical fiber 18a1 to the second interrogator 16b. The FBG superheat sensors 58a reflect a specific wavelength range of the light in order to detect whether an overheat condition is present in the locations of each of the 58a superheat FBG sensors along the optical fiber 18a1. The FBG temperature sensors 60a reflect a specific wavelength range of the light, in order to detect a current temperature of the locations of each of the superheat FBG sensors 58a along the optical fiber 18a1. The break 62a is the result of, for example, physical trauma, fatigue or other damage suffered by optical fiber 18a1 and has the effect of corrupting or blocking an optical signal sent via optical fiber 18a1.
[0062] The incorporation of several different LRUs in the superheat detection system 10 allows detection in several regions of the aircraft 12. Separating the optical fiber into separate LRUs also facilitates the replacement of individual LRUs in comparison to the possible need to remove the all of an optical fiber in an overheat detection system that uses a single optical fiber for all areas of the aircraft 12. In addition, the double interrogator configuration shown in FIG. 4A allows optical fiber 18a1 to be optically probed from both ends of optical fiber 18a1. This capability and functionality is beneficial because if the optical fiber 18a1 is damaged and sustains, for example, the break 62a, optical signals can be sent from both sides of the break 62a. Consequently, the techniques of this disclosure may allow the superheat detection system 10 to gather data from the FBGs located on both sides.
Petition 870190014459, of 02/12/2019, p. 110/162 / 62 of break 62a, instead of a single side, as in a configuration that incorporates only a single interrogator at one end of the optical fiber. [0063] FIG. 4B is a simplified block diagram of the left LRU 52L and right LRU 52R and shows the first interrogator 16a, the second interrogator 16b, the left LRU 52L (including optical fiber 18L, the first connector 54L, the second connector 56L, the 58L overheating FBG sensors and 60L FBG temperature sensors) and the right 52R LRU (including 18R optical fiber, first 54R connector, second 56R connector, 58R overheating FBGs sensors and 60R break and 62B temperature sensors optical fiber 18R). The left LRU 52L and the right LRU 52R are substantially similar to the first LRU 52a of FIG. 4A. In FIG. 4B, the left LRU 52L and the right LRU 52R are connected to each other in an end-to-end arrangement. The second left connector 56L of the left LRU 52L is connected to the first right connector 54R of the right LRU 52R. In this non-limiting mode, two consecutive LRUs are shown as connected in series. In other non-limiting modalities, more than two LRUs can be connected consecutively and in series to form a chain of multiple LRUs that can span several or all aircraft zones 12.
[0064] FIG. 5A is a block diagram of interrogator 16a and shows interrogator 16a (with optical transmitter 20a, detector 22a, couplers 26, including first level coupler 64, second level couplers 66a and 66b and third couplers level 68a, 68b and 68c, detectors 70a, 70b and 70c and optical switches 72a, 72b and 72c) and the first, second and third optical fibers 18a, 18b and 18c (with the respective first connectors 54a, 54b and 54c).
[0065] The interrogators 16a and 16b (shown in FIGS. 4A and 4B) are substantially similar and, for ease of discussion, the interrogator 16a with the optical transmitter 20a, detector 22a and memory
Petition 870190014459, of 02/12/2019, p. 111/162 / 62 computer readable 24a will be discussed in more detail with reference to FIG. 5A. The first level coupler 64, second level couplers 66a and 66b and third level couplers 68a, 68b and 68c are optical devices with one or more optical inputs and one or more optical outputs and which are able to divide an optical signal into multiple channels. Detectors 70a, 70b and 70c are receivers configured to receive an optical signal. Optical switches 72a, 72b and 72c are in-line devices that are configured to selectively block optical signals.
[0066] Controller 14 (shown in FIG. 1) is operatively connected to interrogator 16a, so that optical transmitter 22a and interrogators 72a, 72b and 72c receive signals from controller 14 and detectors 22a, 70a, 70b and 70c send signals to controller 14. The first level coupler 64 is arranged on the first interrogator 16a and is optically connected to the optical transmitter 20a, detector 22a and second level couplers 66a and 66b. The second level coupler 66a is arranged on the first interrogator 16a and is optically connected to the first level coupler 64 and the third level couplers 68a and 68b. The second level coupler 66b is arranged on the first interrogator 16a and is optically connected to the first level coupler 64 and the third level coupler 68c. The third level coupler 68a is arranged on the first interrogator 16a and is optically connected to the second level coupler 66a, detector 70a and optical switch 72a. The third level coupler 68b is arranged on the first interrogator 16a and is optically connected to the second level coupler 66a, detector 70b and optical switch 72b. The third level coupler 68c is arranged on the first interrogator 16a and is optically connected to the second level coupler 66b, detector 70c and optical switch 72c.
[0067] Detector 70a is placed on the first interrogator 16a and is connected optically to the third level coupler 68a. Detector 70b is
Petition 870190014459, of 02/12/2019, p. 112/162 / 62 disposed in the first interrogator 16a and is connected optically to the third level coupler 68b. The detector 70c is placed on the first interrogator 16a and is connected optically to the third level coupler 68c. The optical switch 72a is arranged on the first interrogator 16a and is optically connected to the third level coupler 68a and the first connector 54a. The optical switch 72b is arranged on the first interrogator 16a and is connected optically to the third level coupler 68b and the first connector 54b. The optical switch 72c is arranged on the first interrogator 16a and is connected optically to the third level coupler 68c and the first connector 54c. In this non-limiting embodiment, switches 72a, 72b and 72c are arranged downstream of the couplers 26 (with a downstream direction flowing from the optical transmitter 20a in a left to right direction, as shown in FIG. 5A). In this non-limiting mode, optical switches 72a, 72b and / or 72c for channel isolation are required for a specific double-ended interrogation configuration.
[0068] In this non-limiting embodiment, detector 22a is used for a TDM portion of the superheat detection system 10. The first level coupler 64, second level couplers 66a and 66b and third level couplers 68a, 68b and 68c divide optical signals originating at optical transmitter 20a and distribute the divided optical signals to optical fibers 18a, 18b and 18c. The first level coupler 64, the second level couplers 66a and 66b and the third level couplers 68a, 68b and 68c are also configured to receive multiple return signals from the fibers 18a, 18b and 18c and mix the return signals in one single channel connected to detector 22a.
[0069] Detectors 70a, 70b and 70c detect optical signals received from individual optical fibers 18a, 18b and 18c. In this non-limiting mode, detectors 70a, 70b and 70c are used for one WDM mode for each
Petition 870190014459, of 02/12/2019, p. 113/162 / 62 one of the optical fibers 18a, 18b and 18c. Optical switches 72a, 72b and 72c selectively block optical signals as they pass through optical switches 72a, 72b and 72c. Optical switches 72a, 72b and 72c are controlled to turn off each channel independently on the first interrogator 16a (and also on the second interrogator 16b with similar or identical components).
[0070] In a double interrogator configuration (as shown in FIGS. 4A and 4B) with both interrogators scanning at the same time, the simultaneous operation of both interrogators can result in difficulty in measuring the reflected signals from the FBG chain due multiple signals crossing each respective channel (or optical fiber). If one of the optical fibers 18 a, 18b or 18c sustains a break, the second interrogator 16b can be activated due to the break in the optical fiber preventing the optical signal from reaching the furthest end of the optical fiber. However, the channels or optical fibers, which are not broken, will have the problem of observing the second interrogator's optical signal, as there is nothing to stop the cross communication of the second optical signal. As such, additional channel isolation is preferable to allow double-ended interrogation for these types of systems.
[0071] Optical switches 72a, 72b and 72c can be controlled to turn off each channel (for example, optical fibers 18a, 18b and 18c) independently, and on each of the first and second interrogators 16a and 16b. Such a configuration of the first interrogator 16a with optical switches 72a, 72b and 72c allows the use of a single laser (for example, optical transmitter 20a) while providing channel independence between each of the optical fibers 18a, 18b and 18c. Optical switches 72a, 72b and 72c are independently controlled to allow channel isolation as needed. In a non-limiting mode, if the first interrogator 16a detects that an optical fiber is open (for example,
Petition 870190014459, of 02/12/2019, p. 114/162 / 62 example, damaged or not transmitting a signal), the second interrogator 16b will wake up from a standby mode in response to a communication from the first interrogator 16a. Only the open optical fiber will be interrogated (i.e., illuminated by the optical transmitter 20b on the second interrogator 16b), while the signals through the remaining optical fibers will be controlled (i.e., blocked) by switches 72a, 72b and / or 72c.
[0072] FIG. 5B is a block diagram of the first interrogator
16a with optical switches 72a, 72b and 72c positioned upstream of the third level couplers 68a, 68b and 68c. FIG. 5B shows interrogator 16a (with optical transmitter 20a, detector 22a, couplers 26, including first level coupler 64, second level couplers 66a and 66b and third level couplers 68a, 68b and 68c, detectors 70a , 70b and 70c and optical switches 72a, 72b and 72c) and the first, second and third optical fibers 18a, 18b and 18c (with the respective first connectors 54a, 54b and 54c). In FIG. 5B, optical switches 72a, 72b and 72c are arranged between second level couplers 66a and 66b and third level couplers 68a, 68b and 68c. This configuration is different from the configuration in FIG. 5A, which includes third level couplers 68a, 68b and 68c arranged between second level couplers 66a and 66b and optical switches 72a, 72b and 72c.
[0073] The alternative configuration shown in FIG. 5B, (that is, having optical switches 72a, 72b and 72c located upstream of third level couplers 68a, 68b and 68), allows individual detectors 70a, 70b and 70c to be used as monitors for the optical signals transmitted by the interrogator opposite, which in this form of non-limiting modality is the second interrogator (for example, as shown in FIGS. 4A and 4B).
[0074] FIG. 6 is a block diagram of the first interrogator with optical switch 72 configured as a 1xN optical switch. FIG. 6 shows interrogator 16a (with optical transmitter 20a, detector 22a,
Petition 870190014459, of 02/12/2019, p. 115/162 / 62 coupler 26 and optical switches 72) and first, second and third optical fibers 18a, 18b and 18c (with the respective first connectors 54a, 54b and 54c). In this non-limiting mode, the optical switch 72 includes a 1x3 optical switch. In other non-limiting embodiments, optical switch 72 may include a 1xN optical switch, where N may be equivalent to more or less than 3 output channels. The optical switch 72, as shown in FIG. 6, provides an alternative configuration to those shown in FIGS. 5A and 5B which allow only one channel to be transmitted and received at any given time (for example, one of the optical fibers 18a, 18b or 18c to receive a signal at a time).
[0075] Controller 14 (shown in FIG. 1) is operationally connected to interrogator 16a so that optical transmitter 22a and switch 72 receive signals from controller 14 and detector 22a sends signals to controller 14. With communication between the first and second interrogators 16a and 16b, the first and second interrogators 16a and 16b (each with respective 1xN optical switches) can cycle through channels without simultaneous transmission on the same channel, thus resulting in a slower total refresh rate, but requiring fewer components and providing significantly better energy efficiency.
[0076] In a non-limiting mode, in order to scan (that is, reflect light) the individual temperature of the FBGs 60 (shown in FIG. 4A and 4B), the pulsed laser light can be used. The pulse duration is short enough that detector 22a sees only feedback signals from one FBG at a time. Typically, this means that the pulse duration is less than half the time needed to travel back and forth (from the first interrogator 16a, for a given FBG and back to the first interrogator 16a) to the next FBG in line versus the current sensor on the line. In a non-limiting mode, a round trip time to an FBG sensor can be equivalent to 1 nanosecond per 10 centimeters
Petition 870190014459, of 02/12/2019, p. 116/162 / 62 long optical fiber. For example, for a separation distance of 0.5 meters, the time is equivalent to 5 nanoseconds, indicating that the pulse duration of the optical signal should be half the duration of the time (for example, 5 nanoseconds) or less. The return response signals are more easily identifiable as the response signals fall to zero between the sensor returns.
[0077] If the separation between sensors and pulse timing is correctly identified, a typical approach would be to sample the return signal from detector 22a using an analog to digital converter and measure the sampling rate timing to match the time of round trip between FBG sensors. For example, for a separation distance of 0.5 meters equivalent to a round trip time of 5 nanoseconds, an example sample rate would be 200 mega-hertz. This sampling rate would provide a sample value for each FBG sensor. An important part of sampling is that the time is such that the center of the sampling coincides with the moment when the pulse is centered on the sensor. If the timing is wrong, the response signal can be sampled during the rising or falling edge of the pulse, or even worse, when there is no return between the pulses.
[0078] For most systems, this is a trivial problem, as timing can be defined by the distance to the start of the first FBG sensor and then repeat with equidistant sensors. In most cases, the timing for the first FBG sensor can also be defined in a calibration table in an interrogator's software. For a non-limiting fiber optic superheat system, such as the superheat detection system 10, a first design criterion avoids updating any calibration tables after the superheat detection system 10 is installed. In this non-limiting modality, a second design criterion is that the overheat detection system
Petition 870190014459, of 02/12/2019, p. 117/162 / 62 can require between six and ten LRU sections, each connected in series to the next connectors (for example, first and second connectors 54 and 56). Since timing calibration between sensors may be prohibited after the superheat detection system 10 is installed on aircraft 12, some options are available.
Timing Markers for Fiber Detection Systems (FIGS. 7-8) [0079] The next parts of the disclosure refer to and discuss time markers for the fiber detection system.
[0080] FIG. 7 is a simplified block diagram of LRU 52 and shows the first interrogator 16a, the second interrogator 16b and the first LRU 52 (including optical fibers 18a, first connector 54, second connector 56, overheating FBG sensors 58, temperature FBG sensors 60 and FBG timing sensors 74). LRU 52 shown in FIG. 7 is substantially similar to the first LRU 52a shown in FIG. 4A and thus discussions of the components of the first LRU 52a of FIG. 4A also apply to LRU 52 shown in FIG. 7. The LRU 52 also includes FBG 74 timing sensors. FBG timing sensors 74 are fiber-optic Bragg grid sensors configured to reflect an optical signal.
[0081] The FBG timing sensors 74 are arranged in and along portions of optical fiber 18a1. In this non-limiting mode, a FBG 74 timing sensor is disposed between the first connector 54a and a FBG 60 temperature sensor that is closest to the first connector 54a. Also in this non-limiting mode, another timing FBG sensor 74 is disposed between the second connector 56a and a temperature FBG sensor 60 that is closest to the second connector 56a. In other non-limiting modes, there may be more or less than two FBG temperature 60 sensors arranged along LRU 52.
Petition 870190014459, of 02/12/2019, p. 118/162 / 62 limit, the 74 FBG timing sensors are required for multiplexed TDM systems, in some cases highly multiplexed. In other non-limiting modalities, the FBG timing sensors 74 can be used with a single type of interrogator or double interrogator design (interrogator at both ends).
[0082] The FBG timing sensors 74 are arranged in and along portions of optical fiber 18a ₁ and reference locations of optical fiber 18a ₁ . During the operation of the superheat detection system 10, the optical transmitter 22a (shown in FIG. 5A-6) emits a first optical signal on the optical fiber 18a through the first interrogator 16a. The first optical signal is reflected by one of the FBG timing sensors 74 to create a response signal. The response signal is received by the detector 22a at the first interrogator 16a from the optical fiber 18a based on the first reflected optical signal. The response signal is received by the detector 22a after a first period of time defining a first time step and a first rate of the response signal. The distance between the first interrogator and the first fiber Bragg grid is detected. The response signal is sampled at a higher sample rate than the first response signal rate. Response signal sampling includes measuring the amount of the response signal with a detector 22a to create sample response rate values.
[0083] The sample response rate values are compared with the response signal to identify which of the sample response rate values correspond to a local maximum of the response signal. (See, for example, FIG. 8 and related discussion). The distance from the first interrogator to the first Bragg grid in timing fiber can be determined by comparing the values of the sample response rate with the detected response signal. For example, controller 14 (shown in FIG. 1) is operationally connected to the first
Petition 870190014459, of 02/12/2019, p. 119/162 / 62 interrogator 16a and is configured to determine the reference locations of the temperature fiber FBG sensors 60 of the optical fiber 18a. The superheat detection system 10 with temperature FBG sensors 60 allows the first and second interrogators 16a and 16b to detect distances to specific timing FBG sensors 74 for each section of optical fiber 18a and adjust the sampling time (or use a method oversampling) to ensure that the sampling coincides with the centers of the return pulses of the timing FBG sensors 74 along the optical fiber 18a. The superheat detection system 10 with temperature FBG sensors 60 adds additional FBG sensors at each fiber-optic detection length 18a that act as timing markers to allow the superheat detection system 10 to self-calibrate the timing required to properly interrogate the sensor chains.
[0084] To align the sampling of the response signal with the timing of the response signal, the return signal is oversampled (sample at a higher rate) and samples that align with the timing of the return pulses for that section of the return signal are analyzed. FIG. 8 shows a representation of this option.
[0085] FIG. 8 shows graph 76, including a representation of the output signal 78 from interrogator 16a and a series of sampling points of a return signal. FIG. 8 shows graph 76, output signal 78, the first channel Ch1, the second channel Ch2, the third channel Ch3, the first cycle 1, the second cycle 2, the third cycle 3, the fourth cycle 4, the first channel 80, the second channel 82 and the pulses of the third channel 84.
[0086] Graph 76 is a graphical representation of light flux measurements for signals correlated to output signal 78, the first channel Ch1, the second channel Ch2 and the third channel Ch3 in relation to the first cycle 1, second cycle 2, third cycle 3 and fourth cycle 4. Output signal 78 is
Petition 870190014459, of 02/12/2019, p. 120/162 / 62 an optical signal sent from interrogator 16a (for example, emitted by optical transmitter 20a) and distributed over optical fiber 18a. The first channel Ch1, the second channel Ch2 and the third channel Ch3 are representative of separate optical fibers, such as optical fibers 18a, 18b and 18c. The first cycle 1, second cycle 2, third cycle 3 and fourth cycle 4 are sequential time steps that are repeated every four steps. The first channel pulses 80, the second channel pulses 82 and the third channel pulses 84 are representative of detected amounts of light (i.e., feedback signals reflected from optical fibers 18a, 18b and 18c) measured by one of the detectors 70a , 70b and 70c.
[0087] Output signal 78 is positioned on the left side of graph 76 to indicate that the start of the output signal coincides with the first cycle 1 (for example, the leftmost one). An amplitude or height and shape of the output signal corresponds to the amount of light and periodic nature of the output signal 78 when the output signal is created and distributed in optical fibers 18a, 18b and 18c. The first channel Ch1, second channel Ch2 and third channel Ch3 represent response signals reflected from FBG sensors arranged in optical fibers 18a, 18b and 18c. In this non-limiting mode, the first channel Ch1, the second channel Ch2 and the third channel Ch3 correspond to optical fibers 18a, 18b and 18c. In other non-limiting modalities, more or less than three channels can be detected.
[0088] The first cycle 1, second cycle 2, third cycle 3 and fourth cycle 4 are sequential periods of time that are of equal duration. The pulses of the first channel 80, the pulses of the second channel 82 and the pulses of the third channel 84 are shown to be assigned to their respective channels (for example, Ch1, Ch2 and Ch3). In relation to the superheat detection system 10, the pulses of the first channel 80, the pulses of the second channel 82 and the pulses of the third channel 84 correspond to the detected return signals from each of the optical fibers 18a, 18b and 18c. The size, shape and
Petition 870190014459, of 02/12/2019, p. 121/162 / 62 pulse spacing of the first channel 80, pulses of the second channel 82 and pulses of the third channel 84 are analyzed to determine the sample response rate values. As shown in FIG. 8, the pulses of the first channel 80, the pulses of the second channel 82 and the pulses of the third channel 84 are shown to be displaced 90 to a multiple of discrete cycles (i.e., representing multiples of a 90 ° displacement or π phase) /2).
[0089] A method for spatially synchronizing a series of timing FBG sensors 74 arranged in optical fibers 18a, 18b and 18c includes the emission by the optical transmitter 20a of a first optical signal (e.g., output signal 78) in the fibers optics 18a, 18b and 18c. The first optical signal is reflected by the FBG timing sensors 74 to create a response signal. The response signals are received by the detector 22a from optical fibers 18a, 18b and 18c based on the first reflected optical signal. The response signals are received by the detector 22a after a first period of time defining a first time step and a first rate of the response signal. The response signal is sampled at a higher sample rate than the first response signal rate. Sampling the response signal comprises measuring the quantity of the response signal with detector 22a (or through detectors 70a, 70b or 70c) on the first interrogator 16a to create sample response rate values (i.e., measured from the pulses of the first channel 80, pulses of the second channel 82 and pulses of the third channel 84). The sample response rate values are compared with the response signal to identify which of the sample response rate values correspond to the local maximum of the response signals. From this comparison, the distance from the first interrogator 16a to the FBG timing sensors 74 can be detected, calculated or determined.
[0090] For example, a sample rate may include a rate greater than the rate of the response signal by a factor of four, therefore, for a non-limiting mode with a response rate of 200
Petition 870190014459, of 02/12/2019, p. 122/162 / 62 mega-hertz, a sampling of 800 mega-hertz could be used. This sampling rate would provide four samples for each required time step. In FIG. 8, the timing of when the four samples are measured / detected is represented by the first cycle 1, second cycle 2, third cycle 3 and fourth cycle 4. Depending on where the pulse was within the timing windows, these samples could not see any light, see the light of the rising or falling edge of the pulse or see the light of the pulse peak. If the pulse is approximately half the width of the timing step, at least two of the samples will fall within the “peak” zone of the pulse. The time marker would indicate exactly which of the samples was aligned for that detection section. Each section would have its own 'calibration' coefficient that simply represents which of the samples (1 to 4) is used for that fiber optic section 18a.
[0091] Timing FBG sensors 74 (for example, as timing markers) allow some relaxation of the manufacturing requirements for the detection lengths and especially the length between the first connector 54a and the first temperature FBG sensor 60. The sensors Timing FBG 74 communicate effectively with the superheat detection system 10, where the start and end of each LRU occur in time and so that the superheat detection system 10 can bypass the intermediate space. Using the FBG sync sensors 74 in this way also allows LRUs to be immune mainly to which end is considered front and which is back. The superheat detection system 10 is able to locate each of the FBG timing sensors 74 and adjust to any installation direction. For the double interrogator configuration (for example, superheat detection system 10 including first and second interrogators 16a and 16b), each of the first and second interrogators 16a and 16b can conduct their own fiber optic calibration measurement
Petition 870190014459, of 02/12/2019, p. 123/162 / 62
18a and FBG time sensors 74 in the opposite order and the first and second interrogators 16a and 16b can develop their own unique calibration numbers.
[0092] In a non-limiting mode, the first and second interrogators 16a and 16b can be placed in their own channel of respective wavelength in a WDM scheme. To facilitate calibration, a large spectral return FBG sensor could be incorporated into LRU 52 (or any of the LRUs 52a, 52b or 52c) so that a single wavelength could locate each of the 74 time FBG sensors, regardless of temperature of the FBG 74 sensors (ie, a central wavelength of an FBG changes with temperature).
[0093] Timing FBG sensors 74 can also act as a bit type to ensure that the various LRUs are installed in the correct locations (ie, error-proof). Since the lengths of the LRUs are predefined, if the superheat detection system 10 finds a separation between two timing FBG sensors 74 to not match the expected distance, an indication that the wrong LRU was installed in a specific location can be sent.
Device and Method of Calibration of Fiber Optic Superheat Systems Based on Fiber Bragg Grid (Figures 9A-9B) [0094] The following portions of the disclosure refer to and discuss a method of self-calibration and a device for superheat systems of optical fiber based on Bragg grid.
[0095] In a non-limiting modality, a design criterion for the superheat detection system 10 includes the ability to detect an overheat event within 5 ° Celsius of a defined limit for each of the Za-Zj zones of the aircraft 12 The temperature detection functionality of the superheat detection system 10 also includes a 5 ° Celsius requirement for accuracy. A typical FBG sensor has a
Petition 870190014459, of 02/12/2019, p. 124/162 / 62 nominal ratio of 10 wavelength displacement picometers per degree Celsius. An accuracy of 5 ° Celsius therefore requires the ability to remain within a 50-picometer wavelength window to maintain 5 ° Celsius. The existing manufacturing capabilities of FBG sensors are capable of writing grids with a central wavelength accuracy of 0.1 nanometers or 100 picometers. In other existing techniques, the accuracy of the central wavelength can be better than 0.1 nanometer, in some cases, as low as .01 nanometer or 10 picometer. However, in this non-limiting mode, none of these precision values will allow the superheat detection system 10 to achieve the required temperature accuracy without calibrating the sensors in any way.
[0096] In this non-limiting modality, a method for self-calibrating the overheat detection system is provided, satisfying a design criterion that requires avoiding the use of the calibration tables whenever an LRU FBG sensor is installed or replaced. .
[0097] In this non-limiting modality, with the criterion for the accuracy of the sensor (for example, +/- 5 ° Celsius of precision (that is, 50 picometers), the existing scales of the manufacturing capacity of the FBG sensors (for example, +/- 100 picometers of the central wavelength capacity) are not so far from the precision requirements.Depending on the precision and manufacturing variation statistics, the existing resources differ by a factor of 2 to a factor of 8 of the required resources. This factor of 2 to 8 eases the calibration requirements, with factor 8 providing the worst case scenario, if FBG sensors could be tested after FBG sensors were manufactured and annealed to their final starting wavelength using a fixed and known temperature, a nominal calibration value for these FBG sensors could be obtained. Using such a value, there would only be a need to place each FBG sensor in one of the
Petition 870190014459, of 02/12/2019, p. 125/162 / 62 eight buckets (ie identification or classification regions) to describe the wavelength of the starting center for an FBG sensor. If the nominal calibration value were passed on to the interrogator, the interrogator could use the nominal calibration value to improve the overall accuracy down to the level required for a specific modality.
[0098] The superheat detection system 10 with the calibration FBG sensors 86 allows the method with one of the calibration FBG sensors 86 to communicate to the first or second interrogators 16a or 16b what their calibration values are, so that the system overheating detection system 10 can satisfy the accuracy requirements. In a non-limiting mode, there is an underlying assumption that each of the optical fibers 18a, 18b and 18c contains FBGs with a variation of the wavelength of the global center that is closest (ie less than) to the value of 10 picometers provided by manufacturers as possible variation for a single optical fiber with a plurality of FBG sensors. The method includes carrying a value of 1-8 which represents in which bin the starting wavelength resides for a given FBG chain (that is, a given optical fiber among 18a, 18b or 18c). These values can be represented in a 3-bit binary sequence. The first interrogator 16a detects that the 3-bit sequence of detector 22a of the superheat detection system 10 can be calibrated based on the 3-bit sequence.
[0099] FIG. 9A is a simplified block diagram of LRU 52 and shows the first interrogator 16a, the second interrogator 16b and the first LRU 52 (including optical fibers 18a, first connector 54, second connector 56, overheating FBG sensors 58, temperature FBG sensors 60 and timing FBG sensors 74 and calibration FBG sensors 86 arranged in a first pattern). LRU 52 shown in FIG. 9A is substantially similar to LRU 52 shown in FIG. 7 and so the discussions of
Petition 870190014459, of 02/12/2019, p. 126/162 / 62 components of LRU 52 of FIG. 7 also apply to LRU 52 shown here in FIG. 9A. LRU 52 additionally includes calibration FBG sensors 86. FIG. 9B is a simplified block diagram of LRU 52 and shows the first interrogator 16a, the second interrogator 16b and the first LRU 52 (including optical fibers 18a, first connector 54, second connector 56, overheating FBG sensors 58, temperature FBG sensors 60 and timing FBG sensors 74 and calibration FBG sensors 86 arranged in a first pattern). FIGS. 9A and 9B are substantially similar and, to facilitate the discussion, will be discussed mainly in unison (with a part of the discussion identifying the differences between the two).
[00100] The calibration FBG sensors 86 are fiber Bragg grid optical sensors configured to reflect an optical signal. The calibration FBG sensors 86 are arranged in and along portions of optical fiber 18a1. In the non-limiting embodiment shown in FIG. 9A, the calibration FBG sensors 86 are located at the ends of the optical fiber 18a and in a position relative to the other FBG sensors in the optical fiber 18A which is closest to the first connector 54a and the second connector 56a. The calibration FBG sensors 86 are shown to be arranged adjacent to the timing FBG sensors 74. In the non-limiting mode shown in FIG. 9B, the calibration FBG sensors 86 are located in multiple positions of the optical fiber 18a between the superheat FBG sensors 58 and the temperature FBG sensors 60. In both non-limiting modes, there are several calibration FBG sensors 86 arranged in the optical fiber 18th. In other non-limiting embodiments, there may be two or more calibration FBG sensors 86 placed on optical fibers 18a, 18b and / or 18c.
[00101] As shown in FIGS. 9A and 9B, the superheat detection system 10 with calibration FBG sensors 86 uses FBGs
Petition 870190014459, of 02/12/2019, p. 127/162 / 62 (ie, calibration FBG sensors 86) as calibration markers in optical fiber 18a at established distances or at wavelength locations adjusted along optical fiber 18a to act as bits in a 3 word bits (for example, calibration constant) that the first and second interrogators 16a and 16b can read to obtain the calibration constant. In a non-limiting mode, two calibration constants are used, a calibration constant for overheating FBG sensors 58 and a calibration constant for temperature 60 FBG sensors. Alternatively or additionally, if there is space in the wavelength or in the spatial regime to write more bits, the calibration constant may consist of 4 or more bits. It is also possible that the calibration constants of 2 or even 1 bit are sufficient. FIGS. 9A and 9B show how these concepts can be applied to a system using wavelength positions (one per bit) or a spatial arrangement in a single wavelength bin where the location represents each bit. In the system that uses spatial arrangement, the spatial location can be referenced to the FBG timing sensors 74 which are used to synchronize the pulse timing to the distributed detection system. In this non-limiting modality, the superheat detection system 10 with calibration FBG sensors 86 can be useful for any FBG system (WDM, TDM, etc.) where there is an opportunity to write additional grids on the detection fiber that can be used for calibration. In other non-limiting modes, the calibration FBG sensors 86 can be used with a single type of interrogator or double interrogator design (interrogator at both ends).
[00102] In any of the approaches represented in the configurations shown in FIGS. 9A and 9B, a torque ‘1’ would indicate when a calibration FBG sensor 86 is present at a reference location and a ‘0’
Petition 870190014459, of 02/12/2019, p. 128/162 / 62 would indicate when there is no 86 calibration FBG sensor at the reference site. In a non-limiting mode, calibration FBG sensors 86 can be used as part of a WDM configuration. An advantage of a wavelength-based approach (ie, WDM) is that WDM allows bidirectional detection of optical fiber. For example, it would not matter which side of the optical fiber 18a is interrogated, there would be no ambiguity in the values. Since most interrogators have a limit on the wavelengths they interrogate, the use of a WDM process can limit the number of zones that can be used in the superheat detection system 10. In another non-limiting modality, a process approach space requires only one compartment of wavelengths, thus facilitating the need for a necessary amount of available wavelength ranges. However, the direction of the optical fiber 18a interrogated becomes important. If optical fiber 18a is interrogated from different directions, the binary word will appear "mirrored". To overcome this, one option is to write two timing FBG sensors 74 on one end of the optical fiber 18a and only one timing FBG sensor 74 on the other end of the optical fiber 18a. This use and orientation of the FBG timing sensors 74 will define what the forward and backward directions are.
[00103] In a non-limiting mode, parts of the superheat detection system 10 include optical fiber detection segments (for example, consecutive LRU series) of approximately 5 meters. In a system that can monitor the FBG sensors every 0.5 meters (as desired in the temperature detection portion of the system), this allows up to eleven calibration bits in that section. If the superheat detection system 10 requires significantly shorter detection lengths, this requirement could affect the ability to create enough bits in that LRU. It is likely that such an instance would need to be
Petition 870190014459, of 02/12/2019, p. 129/162 / 62 treated with the WDM approach. Some combinations of wavelength and spatial distribution are also possible (for example, WDM, TDM and / or a combination of WDM and TDM).
[00104] In another non-limiting mode, a second optical transmitter (for example, laser) can be added in a different set of wavelengths to the superheat detection system 10 (for example, how to add a L-band laser to a band system, etc.). Calibration FBG sensors 86 can be written on optical fiber 18a for the new wavelengths of the second optical transmitter, thus eliminating the worry of using detection wavelengths for calibration. This can add some WDM elements and a second high-speed detector to the superheat detection system 10 as well. In another limiting modality, the calibration FBG sensors 86 would be written on the optical fiber 18a after any detection FBG (for example, thermal, temperature and / or timing FBG sensors) were written on the optical fiber 18a and annealed (thus fixed in wave-length). As such, a manufacturing process may include a two-step process with both steps completed before any cabling is applied to optical cable 18a.
[00105] In a non-limiting mode, the calibration information determined by the optical fiber 16a refers to central wavelengths of each of the FBGs (overheating or temperature) in the optical fiber 16a. FBGs (for example, superheat FBG sensors 58a and temperature FBG sensors 60a) are written on optical fiber 16a with an expected central wavelength projected at some initial temperature (for example, 25 ° Celsius). During the operation of the superheat detection system 10, the central wavelengths of the FBG corresponding to that initial temperature can shift from 0.1 to 0.2 nanometers. Since 1 ° Celsius can
Petition 870190014459, of 02/12/2019, p. 130/162 / 62 cause about 10 picometers of wavelength change, this variation from 0.1 to 0.2 nanometers can result in errors of 10 ° to 20 ° Celsius. As such, the calibration FBG sensors 86 can be used to calibrate the superheat detection system 10, informing the superheat detection system 10 something about the initial central wavelengths for the optical fiber 16a. The initial temperature variations are divided into smaller deposits (for example, eight deposits) so that the error goes from 10 ° to 20 ° Celsius to 1 ° to 2.5 ° Celsius, identifying in which of the eight buckets the central wavelengths fit together. In this non-limiting example, the eight deposits can be described by a three-bit word. Then, we would write three calibration FBG sensors 86 on optical fiber 16a, which represent the bits in that word. In another non-limiting modality, to provide calibration for the 58 and 60 superheat and temperature FBG sensors, there may be a total of three calibration 86 FBG sensors for each type of 58 and 60 superheat and temperature sensors or a total of six calibration FBG sensors 86 representing the calibration bits.
Discussion of Possible Modalities [00106] The following are non-exclusive descriptions of possible modalities of the present invention.
[00107] A system configured to monitor the temperature in a plurality of zones of an aircraft includes an optical fiber with first and second ends, first and second connectors and a first interrogator. The optical fiber includes a plurality of fiber Bragg grids, arranged in the optical fiber. The first connector is disposed on the first end of the optical fiber and the second connector is disposed on the second end of the optical fiber. The first interrogator is connected to the first connector and includes an optical switch. The optical switch is in optical communication with the first fiber optic connector and is configured
Petition 870190014459, of 02/12/2019, p. 131/162 / 62 to selectively block the transmission of the optical signal to the optical fiber to prevent the optical fiber from receiving the optical signal from the interrogator.
[00108] The system of the previous paragraph may optionally include, additionally and / or alternatively, any one or more of the following additional features, configurations and / or components.
[00109] A second interrogator can be connected to the second fiber optic connector, where the system can be configured to allow temperature monitoring in the plurality of zones from the first or second interrogator.
[00110] An optical transmitter can be configured to provide an optical signal to the optical fiber, a first detector can be configured to receive an optical response from the optical fiber and / or a coupler can be connected to the optical transmitter and / or the detector, in that the coupler may be in optical communication with the optical switch.
[00111] A controller can be operatively connected to the detector and / or configured to determine at least one temperature for each of the plurality of zones based on the optical response and / or issue an indication for detected zones of the plurality of zones in which at least minus one temperature can be higher than a limit value.
[00112] The controller can be configured to control the optical transmitter and / or determine at least one temperature for each of the plurality of zones using at least one among time division multiplexing (TDM) and wavelength division multiplexing (WDM).
[00113] The aircraft system can be a bleed air system and in which the plurality of zones can comprise bleed air ducts.
[00114] The optical transmitter can be configured to provide the optical signal as at least one of an adjustable wavelength laser and a broadband laser.
Petition 870190014459, of 02/12/2019, p. 132/162 / 62 [00115] A plurality of optical fibers, where the first interrogator can include a plurality of optical switches, where each optical switch can correspond to one of each of the optical fibers, where the optical switches can be configured to control the optical signal blocking of the optical transmitter for the plurality of optical fibers.
[00116] The optical fiber can comprise a plurality of replaceable units in line, each including a portion of optical fiber, a pair of connectors and / or a plurality of fiber Bragg grids that can be arranged in the optical fiber portion.
[00117] A method of detecting thermal conditions for a plurality of zones in an aircraft system includes the emission, by a first optical transmitter arranged in a first interrogator, of a first optical signal. The first optical signal is distributed over an optical fiber by a first coupler. The first optical signal is selectively blocked by an optical switch on the first interrogator from being transmitted to the optical fiber. A second optical signal is emitted by a second optical transmitter arranged in a second interrogator on the optical fiber. A response signal based on the second optical signal is received from the optical fiber by a second optical receiver on the second interrogator. At least one temperature, based on the response signal, for a portion of the plurality of zones is determined using at least one of the first and second interrogators.
[00118] The method according to the previous paragraph can optionally include, additionally and / or alternatively, any one or more of the following steps, characteristics, configurations or additional components.
[00119] The first optical signal can be distributed by a first coupler on a plurality of optical fibers; an optical switch on the
Petition 870190014459, of 02/12/2019, p. 133/162 / 62 the first interrogator can selectively block the first optical signal from being transmitted to at least one of the plurality of optical fibers; a second optical transmitter arranged on a second interrogator can emit a second optical signal on the plurality of optical fibers; a second optical receiver in the second interrogator can receive a response signal from the optical fibers based on the second optical signal; and / or a controller can determine at least one temperature for a part of the plurality of zones based on the response signal.
[00120] The optical fiber may include Bragg grids and / or in which the emission, by the first or second optical transmitter, of the first and second optical signals can comprise the emission of the optical signal using at least one among a wavelength laser adjustable scanning and a broadband laser; and / or in which the determination, using the controller, of at least one temperature for each of the plurality of zones may comprise the determination of at least one temperature based on at least one among time division multiplexing (TDM) and multiplexing by wavelength division (WDM).
[00121] A first portion of the optical fiber can be monitored with the first optical signal until a rupture in the optical fiber, where the first portion of the optical fiber can extend from the first interrogator to the rupture in the optical fiber; and / or a second portion of the optical fiber can be monitored with the second optical signal until the break in the optical fiber, where the second portion of the optical fiber can extend from the second interrogator to the break in the optical fiber.
[00122] The first optical switch of the first interrogator and / or a second optical switch of the second interrogator can be opened in response to a break in a portion of the optical fiber, where the second optical switch can be in optical communication with the optical fiber at one end of the optical fiber opposite the first interrogator.
Petition 870190014459, of 02/12/2019, p. 134/162 / 62 [00123] A detection system includes an optical fiber, a first connector, a second connector, a first interrogator, a second interrogator and a controller. The optical fiber includes a first end, a second end and a plurality of fiber Bragg grids arranged in the optical fiber. The first connector is disposed on the first end of the optical fiber and the second connector is disposed on the second end of the optical fiber. Each of the first and second interrogators includes an optical transmitter, a detector and an optical switch. The optical transmitter is configured to emit an optical signal. The first detector is configured to receive an optical response from the optical fiber. The optical switch is in optical communication with the optical fiber and is configured to selectively block the transmission between the optical fiber and the optical transmitter and the detector to prevent the detector from the first interrogator and the second interrogator from receiving a signal from the optical transmitter of the other between the first interrogator and the second interrogator.
[00124] The system of the previous paragraph can optionally include, additionally and / or alternatively, any one or more of the following additional features, configurations and / or components.
[00125] The detection system can be configured to allow the optical switches of the first and second interrogators to allow the transmission of an optical signal when a break in the optical fiber is detected.
[00126] The detection system can be configured to be used in an aircraft, in which the plurality of zones of the optical fiber can refer to a plurality of zones in the aircraft.
[00127] The optical fiber, the first connector and the second connector can constitute an in-line replaceable unit, in which the system can comprise a plurality of in-line replaceable units that can be configured to be arranged throughout the plurality of zones of a
Petition 870190014459, of 02/12/2019, p. 135/162 / 62 aircraft.
[00128] The controller can be configured to control the optical transmitter and / or determine at least one temperature for each of the plurality of zones using at least one among time division multiplexing (TDM) and wavelength division multiplexing (WDM).
[00129] A plurality of Bragg grids in superheat fiber can be arranged in the optical fiber; a plurality of temperature fiber Bragg grids can be arranged on the optical fiber, wherein the plurality of temperature fiber Bragg grids can be sandwiched between the plurality of superheat fiber Bragg grids; and / or a timing fiber Bragg grid can be arranged on the optical fiber at a reference location of the optical fiber.
[00130] A system configured to monitor a plurality of zones of an aircraft includes a first connector, a second connector, an optical fiber, a first interrogator and a controller. The first and second connectors are in optical communication. The optical fiber can extend between the first and second connectors, the optical fiber with first and second ends, in which the first end of the optical fiber is connected to the first connector, in which the optical fiber comprises: a first Bragg grid in timing fiber arranged in the optical fiber in a reference location of the optical fiber. The first interrogator is connected to the first end of the optical fiber and is configured to provide a first optical signal to the optical fiber and to receive a first timing signal from the optical fiber. The first timing fiber Bragg grid is configured to provide the first timing signal with information related to the first timing fiber Bragg grid. The controller is operatively connected to the first interrogator and configured to determine the fiber reference location
Petition 870190014459, of 02/12/2019, p. 136/162 / 62 optics based on the first timing signal received by the first interrogator.
[00131] The system of the previous paragraph can optionally include, additionally and / or alternatively, any one or more of the following additional features, configurations and / or components.
[00132] A plurality of temperature fiber Bragg grids can be arranged on the optical fiber.
[00133] A second interrogator can be connected to the second end of the optical fiber, where the second interrogator can be configured to provide a second optical signal to the optical fiber and to receive a second timing signal from the optical fiber.
[00134] A second Bragg grid on timing fiber can be arranged on the optical fiber, where the second Bragg grid on timing fiber can be configured to indicate a second optical fiber reference location.
[00135] The optical fiber, the first connector and the second connector can constitute a replaceable unit in line, in which the system can comprise a plurality of replaceable units in line arranged along the plurality of zones of the aircraft.
[00136] The first Bragg grid in timing fiber can be configured to indicate a starting point of an in-line replaceable unit and where the second Bragg grid in timing fiber can be configured to indicate a point of arrival of the unit replaceable online.
[00137] A method of spatial synchronization of a series of sensors arranged in an optical fiber in a system includes the emission, by a first optical transmitter arranged in a first interrogator connected to the optical fiber, a first optical signal in the optical fiber. The optical fiber includes a plurality of fiber Bragg grids arranged in the optical fiber and a
Petition 870190014459, of 02/12/2019, p. 137/162 / 62 first Bragg grid in timing fiber arranged in the optical fiber at a distance from the first interrogator. The first optical signal is reflected with the first timing fiber Bragg grid to create a response signal. The response signal is received by a first optical receiver in the first interrogator from the optical fiber based on the first reflected optical signal, in which the response signal is received by the first optical receiver after a first period of time defining a first time step and a first rate of the response signal. The response signal is sampled at a higher sample rate than the first response signal rate. Response signal sampling includes measuring the amount of the response signal with a detector on the first interrogator to create sample response rate values. The sample response rate values are compared to the response signal to identify which of the sample response rate values correspond to a local maximum of the response signal. [00138] The method according to the previous paragraph can optionally include, additionally and / or alternatively, any one or more of the following steps, characteristics, configurations or additional components.
[00139] The first optical signal may comprise pulsed laser light.
[00140] The distance between the first interrogator and the first Bragg grid in timing fiber is detected.
[00141] The plurality of fiber Bragg gratings may comprise a plurality of temperature fiber Bragg gratings arranged in the optical fiber.
[00142] The sampling rate that can be greater than the first rate of the response signal by a factor of two or more.
[00143] The optical fiber, the first connector and / or the second connector can constitute a replaceable unit in line, in which the system can
Petition 870190014459, of 02/12/2019, p. 138/162 / 62 comprise a plurality of in-line replaceable units arranged across the plurality of areas of an aircraft.
[00144] A starting point of an online replaceable unit can be located based on the sample response rate values, where the online replaceable unit can comprise: a portion of the optical fiber; a first connector can be connected to a first end of the optical fiber portion; a second connector can be connected to a second end of the optical fiber portion; a second Bragg grid in timing fiber can be configured to indicate a point of arrival for the replaceable line unit based on the sample response rate values; and / or the arrival point of the replaceable line unit can be located.
[00145] An overheat detection system includes the first and second connectors in optical communication, an optical fiber, first and second interrogators and a controller. The optical fiber extends between the first and second connectors and includes first and second ends, with the first end of the optical fiber connected to the first connector. The optical fiber includes a plurality of temperature fiber Bragg grids, a first time fiber Bragg grid and a second time fiber Bragg grid. The first Bragg grid in timing fiber is arranged on the optical fiber in a reference location of the optical fiber. The second Bragg grid in timing fiber is arranged in the optical fiber and is configured to indicate a second optical fiber reference location. The first interrogator is connected to the first end of the optical fiber and is configured to provide a first optical signal to the optical fiber and to receive a first timing signal from the optical fiber. The first timing fiber Bragg grid is configured to provide the first timing signal that includes information related to the first fiber Bragg grid
Petition 870190014459, of 02/12/2019, p. 139/162 / 62 timing of the first interrogator. The first interrogator is connected to the second end of the optical fiber and is configured to supply a second optical signal to the optical fiber and to receive a second timing signal from the optical fiber. The controller is operatively connected to the first interrogator and is configured to determine the optical fiber reference location based on the first timing signal received by the first interrogator.
[00146] The system of the previous paragraph may optionally include, additionally and / or alternatively, any one or more of the following additional features, configurations and / or components.
[00147] The detection system can be configured to be installed on an aircraft.
[00148] The optical fiber, the first connector and / or the second connector can constitute an in-line replaceable unit, in which the system can comprise a plurality of in-line replaceable units configured to be arranged throughout the plurality of zones of an aircraft.
[00149] The first interrogator can also include: an optical transmitter configured to supply the optical signal to the optical fiber; a first detector configured to receive an optical fiber response signal; and / or a coupler connected to the optical transmitter and / or the detector.
[00150] An optical switch can be in optical communication with the first optical fiber connector, where the optical switch can be configured to selectively block the transmission of the optical signal to the optical fiber.
[00151] The controller can be configured to control the optical transmitter and determine at least one temperature for each of the plurality of zones using at least one among time division multiplexing (TDM) and wavelength division multiplexing (WDM) ).
Petition 870190014459, of 02/12/2019, p. 140/162 / 62 [00152] A system configured to monitor a plurality of zones on an aircraft includes an inline replaceable unit, a first interrogator and a controller. The inline replaceable unit includes first and second connectors for optical communication and an optical fiber that extends between the first and second connectors. The first end of the optical fiber is connected to the first connector. Optical fibers include a first plurality of fiber Bragg grids arranged in the optical fiber and a plurality of calibration fiber Bragg grids located in a pattern that provides information related to an in-line replaceable unit calibration value based on length central waveform of each of the first plurality of fiber Bragg grids. The first interrogator is connected to the in-line replaceable unit at the first end of the optical fiber and is configured to provide a first optical signal to the optical fiber and to receive a first optical response signal from the optical fiber. The controller is operatively connected to the first interrogator and is configured to determine the calibration value of the inline replaceable unit.
[00153] The system of the previous paragraph can optionally include, additionally and / or alternatively, any one or more of the following additional features, configurations and / or components.
[00154] A plurality of temperature fiber Bragg grids can be arranged on the optical fiber.
[00155] The plurality of calibration fiber Bragg grids can further be configured to indicate a first calibration value, where the first calibration value can be based on the central wavelengths of the plurality of superheat fiber Bragg grids.
[00156] A second optical transmitter can be connected optically to the optical fiber, where the second optical transmitter can be configured to provide a second optical signal to the optical fiber.
Petition 870190014459, of 02/12/2019, p. 141/162 / 62 [00157] The second optical transmitter can be arranged on a second interrogator connected to the second end of the optical fiber, where the second interrogator can be configured to supply the second optical signal to the optical fiber and to receive a second response optical fiber optics.
[00158] The first interrogator may comprise: an optical transmitter configured to provide an optical signal to the optical fiber; and / or a first detector configured to receive an optical response from the optical fiber, wherein the first detector can be operatively connected to the controller.
[00159] The system can comprise a plurality of replaceable units in line arranged along the plurality of zones of the aircraft. [00160] A plurality of temperature fiber Bragg grids can be arranged on the optical fiber, wherein the plurality of temperature fiber Bragg grids can be sandwiched between the plurality of superheat fiber Bragg grids.
[00161] The plurality of temperature fiber Bragg grids can further be configured to indicate a first calibration value, wherein the second calibration value can be based on the central wavelengths of the plurality of temperature fiber Bragg grids.
[00162] A method to calibrate a fiber optic superheat system includes the emission of a first optical signal on the optical fiber with a first optical transmitter arranged on a first interrogator connected to an optical fiber. The optical fiber includes a plurality of superheat fiber Bragg grids arranged in the optical fiber and a plurality of calibration fiber Bragg grids arranged in the optical fiber. The first optical signal is reflected with at least one of the plurality of calibration fiber Bragg grids to create a response signal. The fiber optic response signal based on the first reflected optical signal is
Petition 870190014459, of 02/12/2019, p. 142/162 / 62 received by a first optical receiver at the first interrogator. The response signal received is detected to identify the presence of each of the various Bragg grids in calibration fiber. A calibration value is determined based on the identified presence of the plurality of calibration fiber Bragg grids.
[00163] The method according to the previous paragraph can optionally include, additionally and / or alternatively, any one or more of the following steps, characteristics, configurations or additional components.
[00164] A plurality of temperature fiber Bragg grids can be arranged on the optical fiber, wherein the plurality of temperature fiber Bragg grids can be sandwiched between the plurality of superheat fiber Bragg grids.
[00165] A central wavelength of at least one of the plurality of superheat fiber Bragg grids and the plurality of temperature fiber Bragg grids can be identified based on the detected presence of the plurality of fiber Bragg grids calibration.
[00166] A calibration value can be assigned to the replaceable unit in line based on the detected presence of the plurality of calibration fiber Bragg grids; and / or the calibration value of the online replaceable unit can be communicated to a controller operationally connected to the optical receiver of the first interrogator.
[00167] The calibration values for all fiber Bragg grids of the inline replaceable unit can be identified.
[00168] The distance from the first interrogator to at least one of the plurality of calibration fiber Bragg grids can be determined based on the calibration value.
[00169] A central wavelength for each of the grids of
Petition 870190014459, of 02/12/2019, p. 143/162 / 62
Fiber bragg can be identified based on the calibration value.
[00170] A detection system includes an online replaceable unit, a first interrogator, a second interrogator and a controller. The inline replaceable unit includes the first and second connectors in optical communication and an optical fiber that extends between the first and second connectors. A first end of the optical fiber is connected to the first connector. The optical fiber includes a plurality of Bragg gratings in superheat fiber, a first Bragg gratings in timing fiber and a plurality of Bragg gratings in calibration fiber. The first Bragg grid in timing fiber is configured to indicate at least one of the start and end points of the in-line replaceable unit. The plurality of calibration fiber Bragg grids are located in a pattern that provides information related to an inline replaceable unit calibration value based on a central wavelength of each of the first superheat fiber Bragg grids. The first interrogator is connected to the in-line replaceable unit at the first end of the fiber optic and is configured to provide a first optical signal to the optical fiber and to receive a first optical response signal from the optical fiber. The first interrogator is connected to the second end of the optical fiber and is configured to provide a second optical signal to the optical fiber and to receive a second timing response signal from the optical fiber. The controller is operatively connected to the first interrogator and is configured to determine the calibration value of the inline replaceable unit.
[00171] The system of the previous paragraph can optionally include, additionally and / or alternatively, any one or more of the following additional features, configurations and / or components.
[00172] The detection system can be configured to be installed on an aircraft.
Petition 870190014459, of 02/12/2019, p. 144/162 / 62 [00173] The controller can be configured to control the optical transmitter and / or determine at least one temperature for each of the plurality of zones using at least one among time division multiplexing (TDM) and multiplexing by wavelength division (WDM).
[00174] An optical transmitter can be configured to supply the optical signal to the optical fiber; a first detector can be configured to receive an optical fiber response signal; and / or a coupler can be connected to the optical transmitter and / or the detector.
[00175] Although the invention has been described with reference to examples of modalities, it will be understood by those skilled in the art that various changes can be made and equivalents can be replaced by elements of the same without departing from the scope of the invention. In addition, many modifications can be made to adapt a particular situation or material to the teachings of the invention without departing from its essential scope. Therefore, it is intended that the invention is not limited to the particular modality (s) disclosed, but that the invention includes all modalities that fall within the scope of the appended claims.

权利要求:
Claims (19)
[1]
1. System configured to monitor a plurality of zones on an aircraft, characterized by the fact that it comprises:
an optical fiber with the first and second ends, wherein the optical fiber comprises a plurality of fiber Bragg grids arranged in the optical fiber;
a first connector disposed on the first end of the optical fiber;
a second connector disposed on the second end of the optical fiber; and a first interrogator connected to the first connector, the first interrogator comprising:
an optical switch in optical communication with the first optical fiber connector, where the optical switch is configured to selectively block the transmission of the optical signal to the optical fiber to prevent the optical fiber from receiving the optical signal from the interrogator.
[2]
2. System, according to claim 1, characterized by the fact that it also comprises a second interrogator connected to the second fiber optic connector, in which the system is configured to allow temperature monitoring in the plurality of zones from the first or of the second interrogator.
[3]
3. System, according to claim 1, characterized by the fact that the first interrogator also comprises:
an optical transmitter configured to provide an optical signal to the optical fiber;
a first detector configured to receive an optical response from the optical fiber; and a coupler connected to the optical transmitter and detector, where the coupler is in optical communication with the optical switch.
Petition 870190014459, of 02/12/2019, p. 146/162
2/6
[4]
4. System according to claim 3, characterized by the fact that the first interrogator is operationally connected to the first detector and is configured to determine at least one temperature for each of the plurality of zones based on the optical response and to produce an indication for the zones detected from the plurality of zones where at least one temperature is above a limit value.
[5]
5. System according to claim 4, characterized by the fact that the first interrogator is configured to control the optical transmitter and determine at least one temperature for each of the plurality of zones using at least one among time division multiplexing (TDM) and wavelength division multiplexing (WDM).
[6]
6. System according to claim 1, characterized by the fact that the optical transmitter is configured to provide the optical signal as at least one of an adjustable wavelength laser and a broadband laser.
[7]
7. System, according to claim 1, characterized by the fact that it also comprises:
a plurality of optical fibers, in which the first interrogator comprises:
a plurality of optical switches, wherein each optical switch can correspond to one of each of the optical fibers, wherein the optical switches are configured to control the optical signal blocking of the optical transmitter for the plurality of optical fibers.
[8]
8. System according to claim 1, characterized by the fact that the optical fiber comprises a plurality of replaceable units in line, each including a portion of optical fiber, a pair of connectors and a plurality of fiber Bragg grids arranged in the optical fiber portion.
Petition 870190014459, of 02/12/2019, p. 147/162
3/6
[9]
9. Method of detecting conditions for a plurality of zones in an aircraft system, characterized by the fact that it comprises:
emission, by a first optical transmitter arranged on a first interrogator, a first optical signal;
distribution, by a first coupler, of the first optical signal on an optical fiber;
selective blocking, by an optical switch on the first interrogator, of the first optical signal to be transmitted to the optical fiber;
emission, by a second optical transmitter arranged on a second interrogator, of a second optical signal on the optical fiber;
receiving, by a second optical receiver in the second interrogator, an optical fiber response signal based on the second optical signal; and determining, using at least one of the first and second interrogators, of at least one temperature for a part of the plurality of zones based on the response signal.
[10]
10. Method, according to claim 9, characterized by the fact that it also comprises:
distributing, by a first coupler, the first optical signal over a plurality of optical fibers;
selective blocking, by an optical switch on the first interrogator, of the first optical signal to be transmitted to at least one of the plurality of optical fibers;
emission, by a second optical transmitter arranged on a second interrogator, of a second optical signal on the optical fiber in the plurality of optical fibers;
receiving, by a second optical receiver in the second interrogator, an optical fiber response signal based on the second optical signal; and
Petition 870190014459, of 02/12/2019, p. 148/162
4/6 determining, using a controller, at least one temperature for a part of the plurality of zones based on the response signal.
[11]
11. Method according to claim 9, characterized by the fact that the optical fiber includes Bragg grids and / or in which the emission, by the first or second optical transmitter, of the first and second optical signals comprises the emission of the optical signal using at least one of an adjustable scanning wavelength laser and a broadband laser; and / or in which the determination, using the controller, of at least one temperature for each of the plurality of zones comprises the determination of at least one temperature based on at least one among time division multiplexing (TDM) and division multiplexing wavelength (WDM).
[12]
12. Method, according to claim 9, characterized by the fact that it further comprises:
monitoring a first portion of the optical fiber with the first optical signal until a break in the optical fiber, where the first portion of the optical fiber extends from the first interrogator to the break in the optical fiber; and monitoring a second portion of the optical fiber with the second optical signal until the break in the optical fiber, in which the second portion of the optical fiber extends from the second interrogator until the break in the optical fiber.
[13]
13. Method, according to claim 12, characterized by the fact that it further comprises:
opening of the first optical switch of the first interrogator and a second optical switch of the second interrogator in response to a break in a portion of the optical fiber, where the second optical switch is in optical communication with the optical fiber at one end of the optical fiber opposite the first interrogator.
Petition 870190014459, of 02/12/2019, p. 149/162
5/6
[14]
14. Detection system, characterized by the fact that it comprises:
an optical fiber with the first and second ends, wherein the optical fiber comprises a plurality of fiber Bragg grids arranged in the optical fiber;
a first connector disposed on the first end of the optical fiber;
a second connector disposed on the second end of the optical fiber; and a first interrogator connected to the first connector and a second interrogator connected to the second connector, comprising each of the first and second interrogators:
an optical transmitter configured to emit an optical signal;
a detector configured to receive an optical response from the optical fiber; and an optical switch in optical communication with the optical fiber, wherein the first optical switch is configured to selectively block the transmission between the optical fiber and the optical transmitter and the detector to prevent the first interrogator and second interrogator detector from receiving a signal from the optical transmitter of the other between the first interrogator and the second interrogator.
[15]
15. Detection system, according to claim 14, characterized in that the detection system is configured to allow the optical switches of the first and second interrogators to allow the transmission of an optical signal when a break in the fiber is detected optics.
[16]
16. Detection system, according to claim 14, characterized by the fact that the overheat detection system is configured to be used in an aircraft, in which the plurality of
Petition 870190014459, of 02/12/2019, p. 150/162
6/6 optical fiber zones relate to a plurality of zones on the aircraft.
[17]
17. Detection system according to claim 16, characterized by the fact that the optical fiber, the first connector and the second connector constitute an in-line replaceable unit, in which the system can comprise a plurality of configured in-line replaceable units throughout the plurality of areas of the aircraft.
[18]
18. Detection system according to claim 14, characterized in that the controller is configured to control the optical transmitter and determine at least one temperature for each of the plurality of zones using at least one among time division multiplexing (TDM) and wavelength division multiplexing (WDM).
[19]
19. Detection system, according to claim 14, characterized by the fact that the optical fiber further comprises:
a plurality of temperature fiber Bragg grids arranged on the optical fiber;
a plurality of temperature fiber Bragg gratings is arranged on the optical fiber, wherein the plurality of temperature fiber Bragg gratings are interspersed between the plurality of superheat fiber Bragg gratings; and a first Bragg grid in timing fiber arranged in the optical fiber in a reference location of the optical fiber.

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法律状态:
2019-09-17| B03A| Publication of a patent application or of a certificate of addition of invention [chapter 3.1 patent gazette]|

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