EP0155108A2 - Système de détection - Google Patents

Système de détection Download PDF

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Publication number
EP0155108A2
EP0155108A2 EP85301267A EP85301267A EP0155108A2 EP 0155108 A2 EP0155108 A2 EP 0155108A2 EP 85301267 A EP85301267 A EP 85301267A EP 85301267 A EP85301267 A EP 85301267A EP 0155108 A2 EP0155108 A2 EP 0155108A2
Authority
EP
European Patent Office
Prior art keywords
detector
roadway
detection
signal
coil
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP85301267A
Other languages
German (de)
English (en)
Other versions
EP0155108A3 (fr
Inventor
Andrew George William Taylor
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TROLL DETECTOR SYSTEMS LIMITED
Original Assignee
TROLL DETECTOR SYSTEMS Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by TROLL DETECTOR SYSTEMS Ltd filed Critical TROLL DETECTOR SYSTEMS Ltd
Publication of EP0155108A2 publication Critical patent/EP0155108A2/fr
Publication of EP0155108A3 publication Critical patent/EP0155108A3/fr
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/01—Detecting movement of traffic to be counted or controlled
    • G08G1/015—Detecting movement of traffic to be counted or controlled with provision for distinguishing between two or more types of vehicles, e.g. between motor-cars and cycles
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/01—Detecting movement of traffic to be counted or controlled
    • G08G1/042—Detecting movement of traffic to be counted or controlled using inductive or magnetic detectors
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/07—Controlling traffic signals
    • G08G1/08—Controlling traffic signals according to detected number or speed of vehicles

Definitions

  • This invention relates to a detection system, and particularly but not exclusively to a detection system for use in monitoring traffic flow along a roadway.
  • Vehicle detection systems which utilise induction loops buried in a roadway and arranged to be responsive to passage of a vehicle over the loop to signal such passage to a control station over a hardwired receiver link.
  • US-A-4302746 there is disclosed a system in which a two-axis magnetometer is used for vehicle detection in place of an induction loop.
  • the magnetometer is incorporated in a self-powered detection unit which is implanted in a hole in the centre of a roadway, the unit detecting the presence of a vehicle by measuring its magnetic field, and then transmitting vehicle presence information to a roadside control unit by way of a radio frequency telemetry link.
  • a detection system comprising a self powered detector having a transmission coil which is, in use, fed with a signal at a predetermined resonant frequency thereby to provide a detection field and a detection coil tuned to said resonant frequency and responsive to entry and exit of an object into and from said detection field; coding means operative to encode the response of the detection coil; a transmitter operative to transmit a signal including the output of said coding means; and a receiver responsive to receipt of a signal from the transmitter to receive information represented by the coded response of the detection coil.
  • the system comprises a detector 1 buried in a hole 9 in the centre of one carriageway 2 of a roadway 3, and a receiver 4 mounted by the side of the roadway 3, possibly at a location remote (eg up to about 9.5 Km) from the detector 1 eg mounted to a traffic light.
  • the detector 1 serves to detect the passage of vehicles over the detector, and to transmit certain information about a detected vehicle, for example its speed, length, number of axles, direction of travel, to an antenna 7 of the receiver 4 by way of a radio frequency telemetry link indicated at 5.
  • the receiver 4 analyses the received information, and in response thereto functions to influence the traffic flow along the roadway 3 or elsewhere, for example by controlling the traffic lights 4 and/or other warning signs.
  • the detector can be mains powered, this requires cables to be laid in the roadway. This may be convenient in some situations, where the detectors are being installed before the roadway is built or in a car park where the width of the road is very restricted, but generally we prefer to provide the detector 1 as a self-powered unit which contains a battery 8 which can be recharged when required by a high energy pulsed signal transmitted from the receiver 4 to the detector 1, as will be described later.
  • the detector 1 is in the form of a hermetically sealed unit comprising a cylindrical plastics material housing containing the circuitry and batteries, preferably potted in a plastics material potting compound.
  • a switch is provided by which the detector 1 can be activated when installed for use, this switch being in the form of a pair of coils adjacent an opening in the housing, and a magnet which is inserted into the opening to provide coupling between the coils thereby to activate the detector 1.
  • the detector is buried at a depth of about one inch (2.5cm) in a hole in a roadway, with its axis vertical, and covered with a sealing material of suitable strength and consistency, this after the detector 1 has been activated.
  • the detector 1 is buried in the hole 9, the hole 9 being closed either by the surface dressing on the roadway or by an optional removable cover 50.
  • the detector 1 is mounted in a plastics container 51 having a closed upper end and the open lower end closed by a removable cover 52.
  • the battery 8 is mounted at the lower end of the container 51 and above that there is mounted electronic parts of the detector 1.
  • the electronic parts are mounted on a printed circuit board 53 mounted inside a tubular frame 54, the tubular frame 54 also incorporating adjacent its upper and lower ends plastics rings 56.
  • the two upper plastics rings 56 each mount a copper coil, the upper copper coil comprising a transmission coil 10 and the lower copper coil a transmission coil 11.
  • the lower plastics rings 56 mount a copper transmission coil 10.
  • the two transmission coils 10 provide between them a field 6 and the receiver coil 11 receives a signal which varies depending upon the disturbances in that field 6, the disturbances being caused by motor vehicles.
  • the upper space in the container 51 mounts a wire aerial (antenna) 22. '
  • the transmission coils 10 are fed from a crystal controlled oscillator 12 at its resonant frequency of 150 kHz, the detection coil 11 being tuned to the same frequency.
  • the transmission coils 10 radiate a three-dimesnional field 6 (of typical dimensions height 60-240cm; width 300-450cm; length along the road approximately 300cm) above the roadway, which field 6 is detected by the detector coil 11.
  • a vehicle enters the field 6 the inductive and capacitive coupling between the transmission coils 10 and the detection coil 11 is changed, the output voltage from the detection coil 11 being decreased.
  • the output signal from the detection coil 11 is fed to a voltage amplifier 13, the output of which is fed by way of a rectifier 14 to a voltage comparator 15 responsive to dynamic voltage changes in its input relative to a negative reference voltage.
  • the voltage amplifier 13 also controls a bistable device 16 which on entry of a vehicle into the field of the transmission coil 10 is switched to a state in which it effects energisation of the remaining circuitry of the detector 1 and which when the vehicle leaves the field is switched back to its original state such that the detector 1 is returned to its normal rest condition ready for detection of a further vehicle.
  • the output of the comparator 15 is fed to a central process 17 which serves to determine therefrom the speed of the detected vehicle, this being proportional to the rate of change in the output from the detection 11 as the vehicle enters the field of the transmission coils 10, and the length of the detected vehicle, this being determined from the time between the vehicle entering and leaving the field of the transmission coils 10 as detected by the detection coil 11, and the speed of the detected vehicle.
  • This information is then fed by the processing device 17 in binary coded form, to a memory 18 where it is held for subsequent transmission by the detector unit 1.
  • the signal detected by the coil 11 may be transmitted and the processing carried out at the receiver 4. It would be simplest to digitise the signal from the detection coil 11 and pass this digitised signal to the receiver 4.
  • An advantage of the use of a detector which provides a limited detection field 6 is that the signal produced by the detection coil contains information which allows one in some circumstancers to deduce the type of vehicle detected.
  • these axle structures result in peaks in the output signal from the detection coil 11.
  • Figures 5 to 8 show signals produced in the course of experiments by various vehicles.
  • the signals are in fact the output of the detection coil 11.
  • Figure 5 there is shown the signal output for the passage of a motor car (a Ford Granada Estate) travelling at a first low speed.
  • Figure 6 shows the signal output for the same motor vehicle travelling at a faster speed (in Figures 5 to 8 the right hand side of the signal is provided by the leading edge of the vehicle).
  • Figure 7 shows the same motor car towing a trailer and it can be seen that the waveform is similar to that shown in Figures 5 and 6 with the addition of a further peak to the left, the further peak being created by the trailer. From this it will be understood that it is easy to distinguish between vehicles which have and do not have trailers.
  • the detector 1 On installation of the detector 1 in a roadway, it is given an identity by means of a unique identification number entered into the memory 18, for example by means of a keyboard temporarily coupled to the detector 1 prior to the unit being buried in the roadway.
  • This unique identification number is retained in the memory, and is A read therefrom with each batch of information read therefrom for transmission, whereby a receiver of the information will be able to determine the source of the information, this enabling a single receiver to monitor a plurality of detectors 1 at different locations.
  • the information relevant to the vehicle is read from the memory 18 by an encoder device 19 in which it is used to modulate a radio frequency carrier which is then passed by way of a pre-amplifier 20 to a transmitter 21 for transmission from the aerial 22 incorporated in the detection unit 1, all this under the control of a clock signal from a clock signal generator 23 connected to the encoder device 19.
  • the memory After transmission of the information from the memory 18, the memory is cleared, apart from the detector identification number, ready for receipt of information relating to a further detected vehicle.
  • the detector 1 includes only a single crystal controlled oscillator, the various signals required, namely the signal for the transmission coil 10, the clock signal, and the signal for modulation and transmission being derived by division from the single oscillator.
  • the detector 1 can have associated therewith a known temperature sensor device 100 operative to measure the temperature at the surface of the roadway, this information being supplied to the encoder device 19 for transmission with vehicle detection information or simply with the detection unit identification number.
  • the sensor device 100 can also include humidity measuring means, this information being transmitted together with the temperature information whereby the possibility of ice on the roadway can be determined by the remote receiver.
  • the humidity measuring means is simply a pair of electrodes of different metals capable of giving a voltage output in the presence of moisture at the surface and thus indicate the possibility of ice if the measured temperature is sufficiently low.
  • the detector 1 is powered by a battery 8 which, once the detector is activated and buried, serves for continual energisation of the transmission circuit for the transmission coil 10 and the reception circuit for the detection coil 11, and on detection of a vehicle serves for energisation of the remaining components of the detector by way of an electronic switch device 23 under the control of the bistable device 16.
  • the detector 1 can also include means to sense the voltage of the battery 8, and to respond to the sensed voltage falling below a predetermined level by causing transmission by the unit of a signal indicating this fact.
  • the remote receiver can > respond to such an indication either by giving a warning that the detector identified requires replacement, or by transmitting a battery recharging signal, comprising bursts of high energy pulses, which is received by the detector 1 by way of an aerial, which can be the transmission aerial 22, and rectified by a rectifier device 24 before being used to recharge the battery 8.
  • the detector 1 is installed in a roadway to detect vehicles passing in a predetermined correct direction along the roadway. The detector 1 will however react to vehicles travelling in the wrong direction, the detection coil 11 giving an output signal of reversed configuration under such circumstances. This additional indication can be transmitted to the remote receiver to give a warning of the incorrect direction vehicle.
  • the remote receiver at which the signal from the detector 1 and the signals from a plurality of similar detectors are received contains a plurality of channels all fed from a single antenna, the channels being of the phase-locked-loop type in order to obtain good performance on a norrow frequency band.
  • Each received signal is demodulated, decoded and stored in a memory for subsequent supply to a processing unit.
  • each received signal contains information identifying the detector transmitting the signal, and thus the processing unit can build up a picture of traffic flow at a plurality of different locations in a roadway network, and in dependence thereon operate to control the traffic as required, for example by controlling traffic lights and other traffic control devices.
  • the detector has been described primarily with respect to transmission of information using radio frequencies where the detector is installed before the roadway is built or where the roadway is very narrow, for example in a car park, it may be economically viable and sensible not only to power the detector by means of a cable laid under the roadway but also to pass the information from the detector to the receiver by means of a cable rather than by a radio frequency link.
  • a single receiver 4 can be associated with a plurality of detectors 1, the information transmitted by a detector 1 including identification information enabling the receiver 4 to identify any transmitting detector 1.
  • the information transmitted by the detector 1 can include, in addition to vehicle information; information in relation to the state of the batteries powering the detector, and information about the roadway conditions, for example the temperature and humidity conditions on the roadway surface.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Traffic Control Systems (AREA)
  • Geophysics And Detection Of Objects (AREA)
EP85301267A 1984-02-24 1985-02-25 Système de détection Withdrawn EP0155108A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8404838 1984-02-24
GB848404838A GB8404838D0 (en) 1984-02-24 1984-02-24 Detection system

Publications (2)

Publication Number Publication Date
EP0155108A2 true EP0155108A2 (fr) 1985-09-18
EP0155108A3 EP0155108A3 (fr) 1987-12-02

Family

ID=10557111

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85301267A Withdrawn EP0155108A3 (fr) 1984-02-24 1985-02-25 Système de détection

Country Status (2)

Country Link
EP (1) EP0155108A3 (fr)
GB (1) GB8404838D0 (fr)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2670018A1 (fr) * 1990-11-29 1992-06-05 Chevalier Jean Pierre Dispositif radio de signalisation d'un danger ponctuel sur le reseau routier.
ES2038892A2 (es) * 1991-05-22 1993-08-01 Garrido Sauro Emilio Sistema avisador fonico y visual para vehiculos automoviles sobre circunstancias del trafico.
EP0618557A1 (fr) * 1993-03-31 1994-10-05 PREH-WERKE GmbH & Co. KG Dispositif de transmission d'informations pour la circulation routière
EP0867849A2 (fr) * 1997-03-28 1998-09-30 Matsushita Electric Industrial Co., Ltd. Système de support pour unité mobile pour détecter le son mouvement par un capteur magnétique
FR2913518A1 (fr) * 2007-03-06 2008-09-12 R2M Technologies Sarl Capteur de presence pour emplacement de parking, reseau de capteurs et procede de gestion dudit reseau.
WO2012155347A1 (fr) * 2011-05-18 2012-11-22 Siemens Aktiengesellschaft Système de détection de métal et détecteur de métal
EP4414962A1 (fr) * 2023-02-08 2024-08-14 Uniwersytet Zielonogórski Procédé et système de commande de trafic au niveau d'intersections routières

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2532231A (en) * 1949-05-21 1950-11-28 Streeter Amet Co Traffic detector
US3346842A (en) * 1965-04-20 1967-10-10 Lab For Electronics Inc Vehicle detectors
US3400365A (en) * 1964-12-30 1968-09-03 Ibm Magnetic vehicle detector with feedback adjustment for ambient conditions
US3839700A (en) * 1973-02-13 1974-10-01 Sperry Rand Corp Traffic sensor
DE2505287A1 (de) * 1974-02-08 1975-08-14 Thomson Csf Auf eine aenderung eines magnetfeldes ansprechende anordnung
US4056815A (en) * 1976-02-03 1977-11-01 Westinghouse Electric Corporation Battery operated transmitter circuit
US4276539A (en) * 1978-06-22 1981-06-30 U.S. Philips Corporation Vehicle detection systems
DE3202626A1 (de) * 1982-01-25 1983-08-04 Elmeg Elektro-Mechanik Gmbh, 3150 Peine Vorrichtung zur erfassung von fahrzeugverkehr
EP0096252A2 (fr) * 1982-06-03 1983-12-21 Flintab AB Système de localisation de véhicules

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2532231A (en) * 1949-05-21 1950-11-28 Streeter Amet Co Traffic detector
US3400365A (en) * 1964-12-30 1968-09-03 Ibm Magnetic vehicle detector with feedback adjustment for ambient conditions
US3346842A (en) * 1965-04-20 1967-10-10 Lab For Electronics Inc Vehicle detectors
US3839700A (en) * 1973-02-13 1974-10-01 Sperry Rand Corp Traffic sensor
DE2505287A1 (de) * 1974-02-08 1975-08-14 Thomson Csf Auf eine aenderung eines magnetfeldes ansprechende anordnung
US4056815A (en) * 1976-02-03 1977-11-01 Westinghouse Electric Corporation Battery operated transmitter circuit
US4276539A (en) * 1978-06-22 1981-06-30 U.S. Philips Corporation Vehicle detection systems
DE3202626A1 (de) * 1982-01-25 1983-08-04 Elmeg Elektro-Mechanik Gmbh, 3150 Peine Vorrichtung zur erfassung von fahrzeugverkehr
EP0096252A2 (fr) * 1982-06-03 1983-12-21 Flintab AB Système de localisation de véhicules

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2670018A1 (fr) * 1990-11-29 1992-06-05 Chevalier Jean Pierre Dispositif radio de signalisation d'un danger ponctuel sur le reseau routier.
ES2038892A2 (es) * 1991-05-22 1993-08-01 Garrido Sauro Emilio Sistema avisador fonico y visual para vehiculos automoviles sobre circunstancias del trafico.
ES2083308A1 (es) * 1991-05-22 1996-04-01 Sauro Emilio Garrido Un sistema avisador fonico y visual para vehiculo s automoviles sobre las circunstancias del trafic o
EP0618557A1 (fr) * 1993-03-31 1994-10-05 PREH-WERKE GmbH & Co. KG Dispositif de transmission d'informations pour la circulation routière
EP0867849A2 (fr) * 1997-03-28 1998-09-30 Matsushita Electric Industrial Co., Ltd. Système de support pour unité mobile pour détecter le son mouvement par un capteur magnétique
EP0867849A3 (fr) * 1997-03-28 2000-08-09 Matsushita Electric Industrial Co., Ltd. Système de support pour unité mobile pour détecter le son mouvement par un capteur magnétique
FR2913518A1 (fr) * 2007-03-06 2008-09-12 R2M Technologies Sarl Capteur de presence pour emplacement de parking, reseau de capteurs et procede de gestion dudit reseau.
WO2012155347A1 (fr) * 2011-05-18 2012-11-22 Siemens Aktiengesellschaft Système de détection de métal et détecteur de métal
EP4414962A1 (fr) * 2023-02-08 2024-08-14 Uniwersytet Zielonogórski Procédé et système de commande de trafic au niveau d'intersections routières

Also Published As

Publication number Publication date
EP0155108A3 (fr) 1987-12-02
GB8404838D0 (en) 1984-03-28

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Inventor name: TAYLOR, ANDREW GEORGE WILLIAM