• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    A vehicle detector (10) comprises a vehicle sensor (14) arranged to detect disturbances caused by a vehicle, a digitizer in a microprocessor (20) connected to the vehicle sensor (14). The vehicle detector (10) further comprises a memory unit (18) connected to the digitizer and arranged for storing the digital representation, an antenna (12) and a transmitter in a radio unit (40). The microprocessor (20) also comprises a control unit arranged for controlling the operation of the vehicle sensor (14) and the transmitter. The vehicle detector has an enclosure (49) which encloses the vehicle sensor (14), the digitizer, the memory unit, the transmitter and the control unit. The enclosure (49) provides protection against mechanical damage and moisture, which enables the enclosure to be placed underground. The antenna (12) is provided outside the enclosure (49) and at a distance from the encapsulation (49) to enable placement of the antenna (12) in a road surface. (Pig. S)
    公开号:SE0950385A1
    申请号:SE0950385
    申请日:2009-05-28
    公开日:2010-11-29
    发明作者:David Kulander；Karl Nilver；Fredrik Zettergren；Patrik Soederberg
    申请人:Sensebit Ab；
    IPC主号:
    专利说明:

    2the radio interface. But to cut power consumption so that the sensor can be powered by a battery, the receiver gets onthe roadside should not be further away than e.g. 30 meters. This means that you need many receivers at the roadside, which is increasingboth the cost and the risk of injury.U.S. Patent 5,880,682 also discloses a system of traction control based on magnetic sensors buried beneaththe surface asphalt of the roadway. The sensor is battery-powered and communicates with a receiver located on the side of the road. Thissystem is intended to be used together with e.g. a bright signal, where the need for a receiver at the roadside does notconsidered cumbersome. But for temporary use or when selling a lot of places for tra blir vomiting, the need becomesreceivers on the side of the road expensive and normally require power supply to the receivers at the roadside.
    A general problem with prior art traffic monitoring detectors is that they are not as suitable for flexible and / orrecurring use.
    SUMMARYAn object of this invention is to provide vehicle detectors and methods for providingtra fi kin information that is more suitable for flexible and / or recurring use. This purpose is achieved withdevices and methods according to the appended claims. In general terms, according to a first aspect, includes avehicle detector a vehicle sensor arranged to detect disturbances caused by a vehicle and a digitizerconnected to vehicle sensor. The digitizer is arranged to encode a signal from the vehicle sensor to digital representation.
    The vehicle detector further comprises a memory unit connected to the digitizer and arranged to store the digitalthe representation, an antenna and a transmitter connected to the memory unit and the antenna. The vehicle detector also includesa control unit arranged to control the use of the vehicle sensor, the digitizer, the memory unit and the transmitter.
    The vehicle detector has an enclosure that encloses the vehicle sensor, digitizer, memory unit, transmitter andthe control unit. The enclosure provides protection against mechanical damage and moisture to the vehicle sensor, digitizer, memory unit,the transmitter and the control unit, which enables the encapsulation to be placed underground. However, the antenna is providedoutside the enclosure and at a distance from the enclosure to enable placement of the antenna in a roadwaysurface coating.
    According to a second aspect, a method of providing traffic information includes sensing disturbances causedof a vehicle, digitization of signals for the disturbances to a digital representation, storage of the digital representationand transmitting signals to a tracking monitoring node using wireless signals. The sensing, the digitizationand the storage is performed in a device placed underground, while the transmission comprises providing signals to betransmitted over a distance to an antenna located within the pavement of a roadway.
    An advantage of this invention is that it enables greater flexibility in the use of vehicle detectors, since thesecan utilize already significant public mobile telecommunications networks as communication resources directly fromthe vehicle detectors. Other advantages are described in connection with various features in the detailed description which follows below.3BRIEF DESCRIPTION OF THE RlTNlNGARNAThe best understanding of the invention and its other objects and advantages may be obtained by reference to the followingdescription together with the accompanying drawings, in which:FIG. 1A is a block diagram of prior art vehicle detector system embodiments;FIG. 1B is a block diagram of an embodiment of a part of a vehicle detector system according to the present invention;FIG. 2 is a schematic representation of the fate of information in an embodiment of a vehicle detector system according tothis achievement;FIG. 3 is a flow chart of steps in an embodiment of a method according to this invention;FIG. 4 is a flow chart of steps in an embodiment of a traffic monitoring method according to this invention;FIG. 5 is a block diagram of an embodiment of a vehicle detector system according to the present invention;FIG. 6 is a block diagram of an embodiment of a microprocessor used in FIG. 5;FIG. Fig. 7 is a block diagram of an embodiment of a radio unit used in Fig. 5; andFIGURES 8A-E are schematic representations of some examples of possible embodiments of antennas andcharging arrangements in connection with vehicle detectors according to this invention.
    DETAILED DESCRIPTIONAll drawings use the same reference numerals for similar or similar elements.
    When detecting changes in the earth's magnetic field caused by passing vehicles, it is important howthe detectors are located in relation to the path of the vehicle. If a detector is placed next to the scale, it can be difficultto distinguish between traffic in different lanes or different directions. The most advantageous locations for detectors forvehicle detection purposes are above or below the vehicle lane. Mounting vehicle detectors above the road is expensiveand complicated, and only a realistic alternative when e.g. sophisticated optical detection is used. This systemthe detectors are therefore preferably placed under the track.
    An alternative to placing the detectors is to place them on top of or inside the surface of the road surface pavement. But one suchposition is very prone to wear and damage. Unless the wheel tracks are limited to being located next to itdetector positions, there is always a risk that the vehicles will drive right over the detectors, which causes considerablemechanical stresses such as wear. In climates where snow can occur, the road surface is often scraped off, which further increasesthe risk of damaging the detectors.
    If the detectors are covered by some kind of protective coating, other disadvantages remain. The road surface is normally quitelarge, and the protective coating must be quite thick to withstand such normal wear. Also refoldedroadways sometimes due to wear and tear. In connection with this, the top part of the remainder is usually removedsurface coating of the road surface to level the surface of the road surface and to obtain a surface which is suitable for repainting. If it existsvehicle detectors present in the surface coating, both the detectors and the road machines can be damaged.
    This problem is solved by digging the detectors deep enough to avoid interaction with the road machines.
    Such a situation is shown in Fig. 1 A. A vehicle detector 10 is located underground under a surface coating 60 or4deeply buried in the pavement 60. The detector 10 is so close to the surface that it can still detect when avehicles pass over the pavement 60.
    Communication between the vehicle detector 10 and an external control system can be arranged in different ways, e.g. through cables orthrough radio communication. In most cases, radio communication is the most attractive solution for providing oneflexible system. In prior art systems of this type, the vehicle detector 10 is provided with an internal antenna or an antennaprovided on the outer surface of the vehicle detector 10. The vehicle detector 10 communicates 3 via the antenna with aaccess point 51 provided fairly close to the roadway. To reduce the power requirement for the radio broadcast and toprovide as short a transmission distance 6 through the ground as possible, the distance to the access point 51 is usuallylimited. Maximum distances of 30 meters have been mentioned. Since the access points 51 must be close to the vehicle detectors 10,they can usually only serve one or a few of them located within a limited geographical area, usually less thanone hundred meters or a few hundred meters from the access point, which makes the systems expensive. In addition, the access points require 51usually electrical installations at the roadside.
    An alternative would be to communicate 2 with a more remote access point, e.g. a base station 50. But then increases as wellthe transmission distance 5 in the ground as the total distance, which requires a higher transmission power. Often this is not compatiblewith battery-powered vehicle detectors 10.
    Greater flexibility and suitability for recurring use of a vehicle detector is provided by enabling aradio connection over longer distances for a vehicle detector placed in a suitable detection position bylow power solutions. The limitation of the power requirements can be achieved in different ways. It is understood from this invention thatthe power requirement of the radio connection plays an important role in the total power requirement. A way to cut down on power requirementsthe radio connection is to provide a radio connection that requires low output power. You can do this byprovide an antenna with good radio conditions to a base station or other access point in itcommunication system with which the vehicle detector is to communicate. Another way is to set up an operating schedule thatcuts down the periods when the radio connection, and thus the transmitter and receiver, are active. Ideally, you should combine boththe alternatives.
    Fig. 1B shows a vehicle detector 10 according to this invention in such a situation. The vehicle detector 10 encloses most of themits components inside an enclosure 49. However, an antenna 12 is provided at a distance from the enclosure 49, connected tothe distance via a cable 11. The distance is long enough to enable the antenna 12 to be placed in the roadwaysurface coating 60, normally close below the surface of the road surface coating 60. The distance between the surface of the road surface coating60 and the antenna 12 is shorter than the distance between the antenna 12 and the enclosure 49, preferably considerably shorter. With otherswords, a ratio between the distance between the surface of the pavement 60 and the antenna 12 and the distance between the antenna12 and the enclosure 49 is less than 1, preferably less than 1/3 and most preferably less than 1/10. Via antenna 12, canthe vehicle detector 10 communicates 1 with a rather remote base station 50, and since the transmission path throughthe earth is short, the required transmission power is relatively insignificant. In addition, the antenna 12 and the cable 11 can be manufacturedas mechanically fragile structures, which do not cause much damage to e.g. machinery for road works, when mechanically encounteredsuch.5Fig. 2 shows a system of vehicle detectors 10. A plurality of vehicle detectors 10 communicate 1 with a base station 50 (ora number of base stations). The base station 52 is part of a cellular communication system 59 and is connected to a core network 52.
    The core network 52 is further connected to other stationary or mobile communication systems or networks, e.g. through the use ofvarious Internet connections 58. A trace monitoring node 70 is connected to the core network 52, possibly through aInternet connection. Thereby, each vehicle detector 10 can be connected to the traffic monitoring node 70.
    The use of base stations in a cellular communication network for communication directly with vehicle detectors has severalbenefits. The vehicle detectors are easy to install. In one embodiment, only the vehicle detectors are placed underground,for example by drilling a hole in the pavement surface, putting the vehicle detector in place and then repairing the hole, whilethe antenna is retained in the pavement surface. Because the vehicle detector is battery powered and no moreaccess point is needed near the vehicle detector, you do not need to install any power supply. In addition, there are nonevisible parts that could be damaged. If the vehicle detector must be inactive for a certain period, thenyou do not need to remove it or protect it from wear and tear. Because all communication takes place via the cellularthe communication network also does not need to configure any hardware. The configuration that may be necessary formonitoring purposes can be arranged directly in the tra n queue monitoring node.In applications that targeted e.g. against pure tra fi vomiting, is a common scenario that the vehicle detectors are asked to be insertedoperation for a certain period and then may be dormant for a longer period before the next measurement period. In such cases it isadvantageous to find ways to reduce the active time of the radio connection as well. During inactive periods, the vehicle detectors can be giveninstructions to turn off all functionalities except those needed for restarting. Functionalities that do notneed to be in operation is e.g. communication functionalities, and the vehicle detectors can be completely disconnected from the cellularthe communications network. When the vehicle detectors are to become active again, the cellular communication network offersdirect access channels, which the vehicle detectors can use to re-establish contact. In this way canfunctionalities in the cellular communication network, which were originally intended for mobility purposes here insteadis used to allow a simple routine for connection and disconnection. Today, they have commercial cellularcommunication networks a fairly good geographical coverage, which means that vehicle detectors can be placed almost anywherepreferably without having to worry about radio conditions.Even in pine where vehicle detectors are actually moved to new positions, the cellular communication network's roaming functionstake care of any reconfiguration of the actual radio contacts. This makes the event exceptionally flexible.
    Fig. 3 illustrates a flow chart of steps in an embodiment of a method according to this invention. The method ofprovision of traffic information starts in step 200. In step 210, disturbances caused by a vehicle are felt by. The signalsfor the disturbances are digitized in step 212 to a digital representation. The digital representation is saved in step 214. The stepssensing 210, digitizing 212 and storage 214 are performed in a device located underground. In step 216 is transmittedthe signals to a traffic monitoring node using radio signals. The transmission step in turn includes the step ofprovide the signals to be transmitted over a distance to an antenna located within the pavement surface. The processends in step 219.6In applications where vehicle detectors are used from time to time, e.g. for tratics billing purposes, the battery life can be extendedif parts of the vehicle detector are switched off during periods of inactivity. According to the preferred embodiments, at leastthe communication functionalities to be completely switched off during periods of inactivity. This further cuts down on power requirementscomparison with solutions where the communication functionalities are only set to a standby mode. In embodiments therecommunication is completely turned off, the vehicle detector must be held responsible for at least the initiation of the reactivation ofthe communication. Because the vehicle detector is not constantly connected to the communication network during the inactivity periodsexternal instructions regarding reactivation cannot be received.
    An embodiment of how such an approach to communication can be built up is shown in Fig. 4. The process begins in steps220. In step 221, a vehicle detector is initiated. A battery, preferably newly charged, is installed and all internal processes are started. in step 222the parts of the vehicle detector responsible for the communication are activated, i.e. the transmitter and receiver, to connectto the cellular communication system. It is conveniently initiated by searching for a direct access channel in the cellularcommunication system, so as to establish a first contact according to a standard for the cellularIn step 223, an initiation message is sent via the cellular communication system to onetra fi queue monitoring node with a message that the vehicle detector with a certain identity number is in operation. Here can also furtherapproximate position information, available sensor hardware. etc. are also reported. The initiation message canprovided as a data packet, e.g. by utilizing GPRS functionalities. The tratic monitoring node usesreceived information for the configuration of the vehicle detector into the monitoring system and responds with aconfirmation message, This confirmation message is received in step 224. The vehicle detector is now ready for operation. Step 221to 224 can be performed before or after the actual placement of the vehicle detector underground.
    When the vehicle detector is placed in its intended position below the road surface and is ready for operation, an order request is sent tothe tra fi queue monitoring node in step 225. In step 226, the tra fi queue monitoring node responds with instructions regarding the intendedfuture operation of the vehicle detector. These instructions, which the vehicle detector receives, may include measurement orders,like for example. indicates a measurement period and types of measurements, or may include a simple order to remain inactive until one in advancefixed time. In an alternative embodiment, such instructions may also be included already in the message providedconfirms the initialization. In step 227, a check is made as to whether the instructions received include an order of immediate inactivity.
    If no such inactivity order is received, the process continues with step 231.
    If the vehicle detector has received an inactivity order up to a predetermined time, the process continues withstep 228, in which most of the processes in the vehicle detector are deactivated and corresponding components are preferably switched on.away from the power supply. Activities for performing the detection of interference, the digitization of signals, the storage ofin other words, the digital representation, transmission of signals and reception of signals are switched off during apre-determined period of inactivity. Preferably, only functionalities are kept for initiating the futurethe reactivation process and the system clock are supplied with power and active. This inactivity condition of the vehicle detectorcontinues for as long as the inactivity order has indicated, i.e. at a predetermined time. This removes the need for oneextreme interaction. The power consumption during this phase can thus be very low. The activity period can have different lengths,depending on the current application, anywhere between a few minutes and several years. During this period, no external device cancommunicate with the vehicle detector.7When the predetermined time is reached, reactivation is initiated in step 229. In this embodiment, reactivationfirst only the transmitter and receiver units, while the parts only involved in the measurement and reporting ofsuch may remain inactive. In step 230, the components of the vehicle detector connect to the communication, i.e. transmitters andreceiver, to the cellular communication system. This is done in the same way as the initial process, preferablyinitiated by searching for a direct access channel for the cellular communication system to establish a first contact.
    The vehicle detector is now ready to receive new instructions and the process returns to step 225. Thus, a transmission ofa request for additional instructions when the inactivity period ends.
    If in step 227 it is determined that no immediate deactivation is to be performed, but instead some kind of measurement is to be made,so the process continues with step 231, in which the components for measurements and processing thereof, e.g. sensor, digitizer,memory device etc. is powered and activated. In response to received measurement instructions, performing noise detection,digitization of signals and storage of the digital representation take place. In a special embodiment comesthe vehicle detector to disconnect from the cellular communication system during such measurement periods, in order to savebattery power, and even the transmitter and receiver may be turned off. In other embodiments, the connection to itcellular communication system is maintained. In step 232, measurements are performed, and in step 233, the measurement results are reported totra fi queue monitoring node. If the vehicle detector was disconnected from the cellular communication system belowmeasurement period, the vehicle detector must activate the transmitter and receiver and re-establish the connection with the cellularthe communication system before reporting can take place. Both the type of measurements and the format and time division ofthe reports were preferably already in the measurement order. If the measurement time is so long that the memory device becomes full, additional shouldreporting opportunities are preferably prepared. In step 234, a check is made as to whether the measurements should continue or not. About fl er measurementsyear ordered, the process returns to step 232 and the transmitter and receiver can be disconnected and turned off again.
    In a special embodiment, if the measuring activity is insignificant, which e.g. may be the case at night, so canthe measurement components are put into a rest position when not in use. This cuts down on power demand, but theythe components for measurement can very quickly be obtained in an active state again. By having an additionalwarning sensor, e.g. a vibration sensor, which consumes very little energy, such a sensor can initiate a process toget the measurement components back up again from idle mode as a vehicle approaches.
    If it was determined in step 234 that no further measurements have been ordered in the last received information, then continuethe process instead to step 235, where the components relating to the measurement and processing thereof are deactivated and de-energized.
    The process proceeds to step 236, where a check is made as to whether the most recently received information included any order forinactivity in connection with the measurements being completed or not. About such an inactivity order that also contains a taskconcerning a predetermined end time, the process proceeds to step 228 for another period of inactivity. If noneInactivity orders have been received, the process returns instead to step 225 to request further instructions.
    The fact that the vehicle detector itself is responsible for the reactivation enables a deactivated condition for the vehicle detector withextremely low power consumption. The disadvantage is that in this deactivated state it cannot be interrupted from the outside. But because itdeactivated condition is so effective, you can instead allow the vehicle detector to be activated quite often toinvestigate whether any measurements should be performed, t.o.m. if most requests are answered with a new oneinactivity order.
    The fl fate diagram described above is just one example of how an operating principle for a vehicle detector canimplemented. As those skilled in the art will appreciate, there are virtually unlimited other possible variations.
    The message type may be different. One can e.g. determine in advance that the received ordem contains only one5 orders, either a measurement order or an inactivity order. Process fl fate can then to some extent be simplified but can beslower and may require more signaling. How the measurements are to be performed and reported can also be t.ex. initiated e.g. inin connection with the initialization, so that only the time of the measurements is determined in the received information. Another possibilitywould be to define more than one measurement session with an inactive period in between, which further reducesthe need for communication for inquiries and orders. In an extreme case, instructions regarding all future operations would be issuedAt the initialization, so that no communication other than reporting of the measurement results would be needed. Such initial instructioncould also be performed via the cellular communication system or by e.g. provide a memory device inthe vehicle detector with such information before the vehicle detector is put in place.In alternative embodiments, which are not currently considered preferred, the vehicle detector could also be configured to15 can be activated from the outside. One possibility is not to allow the vehicle detector to be completely disconnected from the cellularthe communication system during inactive periods, and thus could still be reached by e.g. different types ofsearch signals. However, most such solutions involve greater power consumption, which reduces battery life.
    A traffic monitoring system according to an embodiment of this invention is shown as a block diagram in Fig. 5.The vehicle detector 10 has, as mentioned above, an enclosure 49, within which most of the functionalities are included.the enclosure 49 provides protection against mechanical damage and moisture to the components inside the enclosure 49. The antenna 12is located at a distance from the enclosure 49 and is connected with a cable 11, to enable placement of the antenna12 inside a pavement surface.In this embodiment, the core of the vehicle detector 10 is a microprocessor 20. The microprocessor 20 is connected to twovehicle sensors 14, in this embodiment magnetometers 13, via their respective amplifiers 16. The magnetometers 13 in this embodimentembodiment are 2-axis magnetometers, but other types of magnetometers or arrangements of magnetometers can alsobe used, depending on the type of information desired. The vehicle sensors 14 years arranged for detection ofdisturbances caused by vehicles, e.g. disturbances in the earth's magnetic field. In other embodiments, the vehicle sensors mayBe of another type, e.g. vibration sensors, sound sensors or RFlD readers. This embodiment comprisesvehicle detector 10 two vehicle sensors 14. However, other embodiments may have different numbers of vehicle sensors 14, depending onfor example on the current application. However, at least one vehicle sensor 14 is required. The additional vehicle sensor 14could be used either as spare equipment or for measuring other aspects of the indications provided by the vehicleinduces. If the sensors 14 are located at different places in the direction of the intended vehicle movement, it will be easier to register35 speed information. The different vehicle sensors 14 may be of the same type or different types. A magnetometer 13 canfor example combined with an RFID reader.
    The measurement signal is provided from the vehicle sensors 14 to the processor 20, which includes a digitizer. The digitizer isarranged to encode the signal from the vehicle sensor to a digital representation. The digital representation of the signal40 is then stored in a memory unit 18, connected to the digitizer. The microprocessor 20 is also connected to a9system clock 22 and an alarm sensor 25. These components are the main responsible components for maintaining a reliablesystem time and for the recall of vehicle sensors from idle mode. The microprocessor 20 is also connected to a radio unit40, which includes a transmitter and a receiver. The radio unit 40 is preferably adapted for communication withuse of GSM and / or GPRS standard. The radio unit is also connected to the antenna for 40 years. Microprocessor 205 further comprises a control unit which is arranged to control the operation of the vehicle sensors, the digitizer, the memory unitand the transmitter. The microprocessor 20 is also connected to a temperature sensor 26. Thereby, the microprocessor 20 cancompensate the measurements for variations in temperature.
    A power source 30, usually a battery, supplies power to all components of the vehicle detector 10. A voltage adapter 2810 ensures that the various components of the vehicle detector 10 are supplied with well-controlled voltage. A number of controllable switches29 are located in the power lines of the temperature sensor 26, the vehicle sensors 14, the memory unit 18, the alarm sensor 25 andthe radio unit 40. These controllable switches 29 are individually controlled by the control unit in the microprocessor 20, so that componentsdisconnected during periods of inactivity. Then only parts of the microprocessor 20 itself, the system clock 22 and are supplied with poweralarm sensor 25.
    The vehicle detector 10 communicates with a base station 50, e.g. a GSM base station, and in this form also viaThe intercom 58, with a tracker monitoring node 70. This tracker monitoring node 70 comprises in this embodiment a server 72for data collection, which is responsible for communication with the vehicle detectors. The data collection server 72 typically deliversmeasurement instructions and receives measurement reports. The data collection server 72 is connected to a data storage unit 74, in which20 reported measurements are stored. A classifier 75 is connected to the data storage unit 74 and processes its data, sothat you get information about e.g. number of vehicles passed or if more sophisticated analysis methods are used, e.g. vehicle typesm.m. The results of these analyzes are displayed on a presentation monitor 78 or can be exported to other computer systems at onedata exporter 76. In alternative embodiments, the data collection server 72 may be configured differently. The server fordata collection could e.g. configured as a distributed system by a number of communicating servers, where e.g. a server25 is responsible for the actual data collection and another server is responsible for classification and other data evaluation.
    Communication between such servers can also be maintained via the Internet or other types of publiccommunication system. In other embodiments of traffic monitoring nodes 70, certain components may be omitted, e.g.monitor and / or data exporter 76.Fig. 6 shows an embodiment of a microprocessor 20 according to Fig. 5. The microprocessor 20 comprises a digitizer 15connected to the various vehicle sensors 14. There is an internal memory unit 24 for storing small amounts of data, whilelarger amounts of data are provided to the memory unit 18 (Fig. 5). There is a control unit 26 for switching offthe vehicle sensors, the digitizer, the memory unit, the alarm sensor and the radio unit (transmitter and receiver) during apredetermined period of inactivity and for activating the radio device (transmitter and receiver) to send a requestFor further instructions when the inactivity period ends. The control unit 26 is also arranged to supply powervehicle sensor, digitizer, memory unit and alarm sensor if measurement instructions are received. The control unit 26 in thisembodiment is also responsible for controlling the transmission of digital representations from the memory device totra fi queue monitoring node. As will be mentioned in more detail below, the digital representation consistspreferably by digital representations of the entire signal source of the signals obtained from the vehicle sensors.The microprocessor 20 also includes a reactivation unit 23, which is responsible for initiating the reactivation of10the vehicle detector or parts thereof when the inactivity period ends. The reactivation unit 23 is therefore connected tosystem clock to have access to a reliable time. Preferably, the reactivation unit 23 is at least partially separatedfrom other functionalities in the microprocessor 20, so that the parts responsible for functionalities not used forthe reactivation unit can be disconnected or at least put into a low power state during the inactivity periods. in othersembodiments, where the inactive microprocessor 20 has a low total power consumption, the entire microprocessor 20 can be keptremain in operation even during periods of inactivity.
    The various components shown in Fig. 6 are normally integrated in a physical unit, the blocks rather indicating differencesin functionality.
    Fig. 7 is a block diagram of an embodiment of a radio unit 40 according to Fig. 5. The radio unit 40 comprises a transmitter 42and a receiver 44, both of which use the same antenna. In this embodiment, the operation of these parts is controlled by the control unitin the microprocessor.
    When a vehicle detector according to this invention is to be placed in a measuring position, this is usually done after the road surfacecoating is complete. A typical procedure is to drill a hole in the coating, and if necessary a piece belowthe coating. The diameter of the hole should preferably be just large enough to allow the enclosure to pass. The depth of the holedetermines the position of the enclosure under the coating and can be carefully adjusted so that you get a good compromisebetween measurement sensitivity and protection against damage. The preferred hole depth is currently assumed to be in the range of 200-300 mm. The holethen refilled with material, preferably the same kind of material that occurs laterally. In other words, in the area belowthe surface coating is filled with a material of the same or similar type as the road surface. within the coating is filledthe hole with a material that is as close as possible to the surface coating. Preferably, the hole is filled with a material that has similarmechanical properties such as the pavement of a road surface. The antenna is provided at the intended position within thisfilling material. Fig. 8a shows an embodiment of a vehicle detector 10. An enclosure 49, preferably in cylindrical shape, contains themost components as described above. An antenna 12, in this embodiment a loop antenna strikes connected with acable 11. The antenna should preferably be designed as a half-wave antenna. the enclosure 49 is placed in the bottom of the drilled hole andthe antenna 12 is kept within the coating when the hole is filled.
    The vehicle detector unit can also be used as an aid in positioning. Such an embodiment is shown in Figs. 8B.
    Even before placement, the antenna 12 can be placed in a volume 39 filled with a material which has mechanical propertiessimilar to a pavement surface in which the antenna 12 is intended to be placed. Examples of possible materials are asphalt, bitumenor epoxy compound. The volume 12 is mechanically attached to the enclosure 49. A hole is drilled to a depth corresponding to the entire unit.height in Fig. 8B. The whole unit is placed in the bottom of the hole, which ensures that the upper part of the vehicle detector 10 does notprotrudes above the surface of the road surface. The cylindrical gap between the vehicle detector and the wall of the hole is filled,for example with materials used to repair minor damage to the road. This volume to be replenished is usually a lotless than the volume of the hole, and more expensive materials can typically be used. The volume 39 thus forms part of the road surfacecoating when the gap is sealed.11In an alternative embodiment, an additional volume of material may be added between the volume 39 and the encapsulation 49. Thisadditional volume could be filled with a material that has vibration damping properties to reduce vibrationsinduced in the coating directly down to the enclosure 49.
    The antenna can be of different types. A loop antenna 31 is used in the embodiments of Figs. 8A and 8B. Fig. 80 instead shows oneembodiment with a vehicle detector 10 having an antenna 12 provided as a winding antenna on a flexiblesubstrate 32 of plastic. Since the technical effect of this acquisition is typically not determined by the tactical choice of antenna canthe device can also be used with other antenna types.
    As mentioned above, the antenna of the vehicle detector is provided inside the pavement of the road surface. But the coating ishowever, not entirely permanent. It is typically prone to wear and erosion. If the detector is located in a place therevehicle wheels pass, the pavement surface will wear down step by step, so that the antenna may eventually appear atthe road surface itself. This process can be strengthened e.g. by using road scrapers to get rid of ice and snow in winter.
    The antenna may therefore be damaged and may eventually cease to function properly. Fig. 8D includes an embodiment of avehicle detector 10 a plurality of antennas 12, in this particular embodiment exemplified by signal antennas 31. Said numberantennas 12 are all provided outside the enclosure 49. The distance of each antenna from the enclosure 49 is adapted toenable placement of said number of antennas 12 at different depths in the pavement of the road surface. To make it easierthe positioning of the antennas, they could possibly be provided in a precast volume analogous to Fig. 8B. With suchstructure, when the wear of the pavement surface has reached the level of the top antenna, this antenna can be destroyed.
    However, it is then possible to switch to the next antenna and continue operation.
    In order to have a relatively well-defined interruption of function for the antenna, the cable to each antenna can be provided with acutting arc 33 which has its top above the level of the main antenna. This means that the cutting arc 33 is worn away before itthe actual antenna is affected. As a result, the antenna can reliably continue in operation until the cutting arc 33 is removed.
    When you have a number of antennas, the vehicle detector should preferably be able to choose on its own which of the antennas tobe used. Therefore, it is preferable if the vehicle detector is arranged to determine which is the antenna which has thebest radio conditions relative to the base station. Normally, this is the highest located, operational antenna in the number of antennaswhich have possible connections to be used for the transmission. The transmission from the vehicle detector should then be controlled tomake use of the antenna that has the best radio conditions. In the vehicle detector this is preferably done by the control unit, whichthus arranged to determine an antenna in said plurality of antennas having the best radio conditions with respect tothe base station and for controlling this antenna for transmissions.
    The above embodiment is also suitable for roads that are re-paved. When the top part of it stillexisting pavement of the roadway is cut off to level the surface of the roadway and provide a surface suitable forreload, one or more antennas may be destroyed. However, a working antenna can still be found in itremaining layers. The fragile construction of the antenna also ensures that the road machine is not damaged. When a newsurface coating is applied, the working antenna can be used for continued communication. There is a slight downside to thisantenna will be buried under the newly provided topcoat, so that the sanding effect can12need to be increased slightly. But the situation is still better than for an antenna that has been located inside the vehicle detector nsencapsulation.
    The power consumption of the vehicle detector is one of the limiting factors when designing the unit. With the latestdevelopments in battery technology, and in applications where only intermittent measurements are to be performed, have a lifespan of 10 yearsfully achievable. But the more often it is used and the more data that needs to be transmitted, the shorter the battery life.In Fig. 8E, an embodiment of a vehicle detector includes a charging arrangement. A positive leader 35 and onenegative conductor 36 is provided from the enclosure 49 to the intended upper portion of the pavement surface. The end ofthe positive conductor 35 constitutes a positive connection point 37 at the upper part of the pavement surface and the end ofthe negative conductor 36 forms a negative connection point 38 at the upper part of the pavement surface. The positivethe conductor 35 and the negative conductor 36 should preferably lie in a volume 34 with an erodible material with mechanicalproperties similar to the surface of the road surface. This volume could conveniently be integrated into a volume comprisingthe antennas if such a volume exists. When the surface coating wears down, the volume 34 and the conductors 35, 36 wear downcorrespondingly, so that they always provide a positive connection point 37 and a negative connection point at the toppart of the road surface.
    If the vehicle detector's batteries need to be charged, a power source can be connected to the positive connection point 37 andthe negative connection point 38. If e.g. a solar cell is used as a power source, the connection can t.o.m. be permanent.
    The control unit in the enclosure 49 can then detect if there is a voltage between the conductors and start arecharge process. In some embodiments, it could be made dependent on the condition of the vehicle detector. l anotherembodiment, on the other hand, the charge control could be completely separated from the other functions of the unit.In a further embodiment, a temperature sensor could be included near the position of the antenna, or at least in contactwith the pavement surface. The temperature sensor would e.g. be able to build in the same volume 34 as the charging conductorsand / or in the same volume as the embedded antennas. The temperature sensor can then be connected to the vehicle detectortemperature sensor, to provide an even more reliable temperature for the road surface.
    In traffic counting applications, there are often requests for the possibility of distinguishing between different vehicle types. l preliminaryexperiments with magnetometer-based sensors, it has been found that the magnetic rays measured as a function oftime includes a wealth of detailed information. In most systems according to known technology with magnetometer-based measurementsthe amount of data is greatly compressed to reduce the amount of data to be transmitted. By making onecompression, however, a lot of information is lost. To be able to detect as many details as possibleconcerning the magnetic signature of the vehicles passing the detector, the vehicle detector is preferably placed directly belowvehicle track. On a typical scale, the sensors should therefore be placed between the intended grooves for each wheel.
    The depth of the sensor is also important. According to this invention, the sensor should be placed under the surface of the road, especially withaccount of wear and damage. However, if the vehicle detector is laid too deep, the road material will attenuate itmeasured magnetic probes. Therefore, it is currently considered preferred to place the vehicle detector at a maximum depth of 20 ombelow the road surface. For the same reasons, it is advantageous to have the actual sensor components located in the upper part ofthe encapsulation, while e.g. batteries and control unit can be placed at the bottom of the enclosure.13By placing the sensors according to the above-mentioned principles, measurements of very accurate magnetic probes are possible.not only the number of vehicles driving past the detector, and perhaps the associated vehicle length, but also informationconcerning the number of wheel axles, the "magnetic mass" of the vehicle, which is normally related to the weight of the vehicle, thespeed, vehicle length and direction of travel are detectable.In a preferred embodiment of this invention, therefore, detailed data from the vehicle sensors is stored in adata storage device in the vehicle detector as digital representations of whole signal forms for signals of the sensedthe disturbances. When the measurements have been completed, these digital representations of the entire signal forms are sent totra fi queue monitoring node. The traceability monitoring node collects a database with original signal forms from the individualssensorema. An advanced analysis of the signal forms can thereby be provided, since large processing capacity canobtained without having to think about a limited battery capacity. Raw data can also be exported from the external databaseanalysis. It is likely that the effect needed to transmit the larger amount of data in some men will beis offset by the improved possibilities for more energy-efficient handling of the signals themselves. Access to the wholesignalforrner also opens up completely new applications for automated traffic monitoring.
    Routines for pattern recognition are currently developing very rapidly, partly as a result of the increasing processing capacitywhich is now available at a relatively low cost. By also utilizing approaches with neural networks can self-learningsystems are built and thereby improve e.g. classification in vehicle classes etc. Even today, it is considered possible to divorcebetween a passenger car, a passenger car with a trailer, a 2-axle truck, a Z-axle truck with a trailer, a 3-axle truck and a 3-axle truck with a trailer. In addition, it is considered possible to determine vehicle speeds with precision even todaybetter than 2.5 km / h.
    The embodiments described above are to be seen as a few illustrative examples of the present invention.
    Those skilled in the art will appreciate that various modifications, combinations, and modifications may be made in the embodiments without departing from the spirit of the invention.the scope of this invention. In particular, partial solutions in the various embodiments can be combined in other arrangements therethis is technically possible. However, the scope of the invention is set forth in the appended claims.
    权利要求:
    Claims (15)
    [1]
    A vehicle detector (10), comprising: a vehicle sensor (14) arranged to detect disturbances caused by a vehicle; A digitizer (22) connected to the vehicle sensor (14) and arranged to encode a signal from the vehicle sensor (14) to a digital representation; a memory unit (18, 24) connected to the digitizer (22) and arranged to store the digital representation; an antenna (12); a transmitter (42) connected to the memory unit (18, 24) and the antenna (12); A control unit (26) arranged to control the operation of the vehicle sensor (14), the digitizer (22), the memory unit (18, 24) and the transmitter (42); and an enclosure (49) enclosing the vehicle sensor (14), the digitizer (22), the memory unit (18, 24), the transmitter (42) and the control unit (26); which enclosure (49) provides protection against mechanical damage and moisture for the vehicle sensor (14), the digitizer (22), the memory unit (18, 24), the transmitter (42) and the control unit (26), which enables the enclosure (49) to be placed under the ground; characterized in that the antenna (12) is provided outside the enclosure (49) and at a distance from the enclosure (49) to enable placement of the antenna (12) within a pavement (60) of a roadway.
    [2]
    Vehicle detector according to Claim 1, characterized by a receiver (44) which, together with the transmitter (42), is arranged for communication with a cellular communication system (59).
    [3]
    The vehicle detector according to claim 2, characterized in that the cellular communication system (59) provides a direct access channel.
    [4]
    Vehicle detector according to Claim 2 or 3, characterized in that the control unit (26) is arranged for controlling communication with a traffic monitoring node (70) via the cellular communication system (59). 30
    [5]
    The vehicle detector according to any one of claims 2 to 4, characterized by a battery (30) which supplies power to the vehicle sensor (14), the transmitter (42) and the receiver (44), and in that the control unit (26) is arranged to switch off at least one of the vehicle sensor (14), the transmitter (42) and the receiver (44) during a predetermined period of inactivity and to activate the transmitter (42) and the receiver (44) and to transmit a request for further instructions when the inactivity period ends.
    [6]
    Vehicle detector according to Claim 5, characterized in that the control unit (26) is arranged to supply power to the vehicle sensor (14) if measurement instructions are received. 15
    [7]
    Vehicle detector according to any one of claims 2 to 6, characterized in that it comprises a plurality of antennas (12) provided outside the enclosure (49) and at a distance from the enclosure (49) to enable placement of said number of antennas (12) on different depth within a pavement surface (60).
    [8]
    Vehicle detector according to claim 7, characterized in that the control unit (26) is arranged to determine an antenna of said plurality of antennas (12) having the best radio conditions relative to a base station of the cellular communication system and to control the transmitter (42) to utilize the top-of-the-line working antenna for transmissions.
    [9]
    Vehicle detector according to one of Claims 1 to 8, characterized in that at least one antenna (12) is provided inside a volume (39) filled with a material with mechanical properties similar to those in the pavement of the roadway where the antenna (12) is to be placed, which volume (39) is mechanically attached to the enclosure (49).
    [10]
    A method of providing traffic information, comprising the steps of: sensing (210) disturbances caused by a vehicle; digitizing (212) signals for the interference to a digital representation; storing (214) the digital representation; and transmitting (216, 233) the signals to a tratics monitoring node (70) using radio signals (1), characterized in that the steps of sensing (210), digitizing (212) and storage (214) are performed in a device located below the ground; which transmitting step (216, 233) comprises the step of providing the signals to be transmitted over a distance to an antenna (12) located in a road surface coating (60).
    [11]
    Method according to claim 10, characterized by the further step of receiving (226) the signals from the tracking monitoring node (70), which transmission steps (216) and reception steps (226) are performed according to standards for a cellular communication system.
    [12]
    Method according to claim 10 or 11, characterized by the further steps: making it impossible (228) to perform the steps of sensing interference, transmitting signals and receiving signals during a predetermined period of inactivity; and performing the steps of transmitting signals (233) and transmitting (225) a request for additional instructions when the inactivity period ends.
    [13]
    The method of claim 12, characterized by the step of initiating the step of transmitting (225) a request for additional instructions by transmitting on a direct access channel in the cellular communication system.
    [14]
    Method according to claim 12 or 13, characterized by the step of enabling the steps sensing (232) of disturbances in response to received measurement instructions. 16
    [15]
    A method according to any one of claims 10 to 14, characterized in that the step of transmitting signals (233) comprises transmitting retrieved said digital representations to the traffic monitoring node (70), which digital representations are digital representations of complete signal forms for signals for the sensed disturbances.
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    同族专利:
    公开号 | 公开日
    SE534180C2|2011-05-24|
    EP2435997B1|2015-01-21|
    CN102369561A|2012-03-07|
    WO2010138057A1|2010-12-02|
    EP2435997B9|2015-06-10|
    US8773287B2|2014-07-08|
    CN102369561B|2014-03-26|
    EP2435997A1|2012-04-04|
    EP2435997A4|2012-12-19|
    US20110121995A1|2011-05-26|
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    SE0950385A|SE534180C2|2009-05-28|2009-05-28|Equipment and method of traffic monitoring|SE0950385A| SE534180C2|2009-05-28|2009-05-28|Equipment and method of traffic monitoring|
    PCT/SE2010/050345| WO2010138057A1|2009-05-28|2010-03-29|Device and method for traffic surveillance|
    CN201080014199.3A| CN102369561B|2009-05-28|2010-03-29|Device and method for traffic surveillance|
    US13/055,789| US8773287B2|2009-05-28|2010-03-29|Device and method for traffic surveillance|
    EP10780878.4A| EP2435997B9|2009-05-28|2010-03-29|Device and method for traffic surveillance|
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