GB1594231A - Transponder/interrogator systems - Google Patents

Transponder/interrogator systems Download PDF

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Publication number
GB1594231A
GB1594231A GB5997/77A GB599777A GB1594231A GB 1594231 A GB1594231 A GB 1594231A GB 5997/77 A GB5997/77 A GB 5997/77A GB 599777 A GB599777 A GB 599777A GB 1594231 A GB1594231 A GB 1594231A
Authority
GB
United Kingdom
Prior art keywords
transponder
interrogator
test
signal
transmitter
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.)
Expired
Application number
GB5997/77A
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.)
Plessey Co Ltd
Original Assignee
Plessey Co 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 Plessey Co Ltd filed Critical Plessey Co Ltd
Priority to GB5997/77A priority Critical patent/GB1594231A/en
Publication of GB1594231A publication Critical patent/GB1594231A/en
Expired legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/40—Means for monitoring or calibrating
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/74—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
    • G01S13/76—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems wherein pulse-type signals are transmitted
    • G01S13/767—Responders; Transponders
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/40—Means for monitoring or calibrating
    • G01S7/4052—Means for monitoring or calibrating by simulation of echoes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/40—Means for monitoring or calibrating
    • G01S7/4052—Means for monitoring or calibrating by simulation of echoes
    • G01S7/4082—Means for monitoring or calibrating by simulation of echoes using externally generated reference signals, e.g. via remote reflector or transponder
    • G01S7/4091—Means for monitoring or calibrating by simulation of echoes using externally generated reference signals, e.g. via remote reflector or transponder during normal radar operation
    • G—PHYSICS
    • G07—CHECKING-DEVICES
    • G07C—TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE
    • G07C9/00—Individual registration on entry or exit
    • G07C9/20—Individual registration on entry or exit involving the use of a pass
    • G07C9/28—Individual registration on entry or exit involving the use of a pass the pass enabling tracking or indicating presence

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  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Train Traffic Observation, Control, And Security (AREA)

Description

(54) IMPROVEMENTS IN OR RELATING TO TRANSPONDER/ INTERROGATOR SYSTEMS (71) We, THE PLESSEY COMPANY LIM ITED, a British Company, of 2/60, Vicarage Lane, Ilford, Essex, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following state ment:- This invention relates to transponder/interrogator systems.
Transponder/interrogator systems comprise a transmitter which forms a part of the transponder and a receiver which forms a part of the interrogator, the transponder transmitter being arranged to transmit data to the interrogator receiver, when the interrogator and the transponder are in the same vicinity.
In such systems failure of the receiver may go undetected especially when communication takes place at irregular intervals and when the system is unmanned and/or automated.
It is an object of the present invention to detect failure of the interrogator receiver.
According to the present invention the interrogator of a transponder-interrogator system comprises a receiver, including means for checking the validity of the received signal, a test transmitter arranged to transmit test signals at intervals to the receiver of the interrogator, inhibit means for inhibiting transmission from the test transmitter when the interrogator receives a signal indicating that the transponder is in the vicinity, an indicator for providing a warning signal, and delay means effective to permit operation of the indicator if valid signals are not received by the receiver for a period determined in the said delay means said period being longer than the said interval between test signal transmissions transmitted by the test transmitter.
Transponder/interrogator systems may be used in transport systems wherein the transponder is associated with a vehicle and the interrogator is stationary or alternatively wherein the interrogator is associated with a vehicle and the transponder is stationary.
The signal indicating that the transponder is in the same vicinity as the interrogator may be provided by switch means operated when a mobile part of the system carrying the transponser or the interrogator, as the case may be, is in a predetermined location.
Alternatively, the signal may be provided by the transponder transmitter.
The interrogator may include means for radiating energy which is received by the transponder and utilised to provide power for its transmitter.
The transmitter of the transponder may be arranged to transmit at a frequency which is a sub-multiple of the frequency at which energy is transmitted to the interrogator.
The interrogator may include an oscillator for providing a signal to provide power for the transponder and divider means responsive to the oscillator for providing at the said intervals trigger signals which are fed to the test transmitter to initiate the said test signals.
The inhibit means may comprise a gate responsive to a signal received by the receiver for inhibiting said trigger signals whereby the trest transmitter is not switched on when signals are being received from the transponder.
Further gating means may be provided responsive in the presence of a received carrier signal and said trigger signals for initiating a validity checking cycle utilising a signal received from the transponder when the test transmitter is inhibited.
Further inhibit means may be provided responsive to the means of checking the validity of the received signal for switching off the test transmitter if a signal of predetermined character is not detected after the test transmitter has been on for a predetermined time.
Thus if a garbled message is received, due to a transponder message being received shortly after the start of a test transmission, the test transmission is switched off.
The transponder interrogator system may be used in a rail transport system whenever the interrogator is carried by a vehicle and one or more transponders are situated along the rail track.
As exemplary embodiment of the invention will now be described with reference to the drawing accompanying the Provisional Specification which is a generally schematic block diagram of a transponder/interrogator system Referring now to the drawing a transponder/interrogator system comprises a transponder 1 and an interrogator as shown within the broken line 2. The interrogator has closely associated with it a test transponder 3. The interrogator comprises an oscillator 4 arranged to provide a signal which is radiated from an aerial 5 at a frequency of 147 kHz. The radiated signal is received by the transponder I and also by the test transponder 3 and utilised in each case, to provide power for a transmitter which is arranged to transmit signals at a frequency of 73.5 kHz which is half the frequency of the signal radiated from the aerial 5.
The transponder 1 in this embodiment is a trackside transponder positioned alongside a railway track and may be one ofa number of transponders which transmits only when a vehicle carrying the interrogator 2 is in the vicinity. The test transponder 3 on the other hand is mounted alongside the interrogator and provides test signals as will hereinafter be explained. Signals from the test transponder 3 or the track side transponder 1 are received by an aerial 6 of the interrogator which feeds a filter and demodulator 7. The demodulator receives a signal on line 8 from the oscillator 4 which is utilised as a frequency and phase reference. The output from the filter and demodulator 7 comprises on line 9 data signals transmitted at a frequency of 9.1kHz and synchronizing or strobe signals fed on line 10.Lines 9 and 10 are fed to error checking apparatus 11 which checks the validity the signals on line 9 and provides an output signal on line 12. When a valid input signal has been received an output is also provided on line 13.
It will be appreciated that the interrogator may receive signals infrequently at intervals which cannot be anticipated and therefore failure of the interrogator receiver may pass undetected unless some form of failure indicator is provided. In order to provide for regular checking of the interrogator receiver the test transponder 3 is fed via an AND gate 14 with pulses which occur every five seconds. These are derived in a divider 15 which is fed from the oscillator 4. In the presence of a received carrier signal a gate control signal is provided on line 16 which is fed via a phase reversal gate 17 to the AND gate 14.
When a carrier signal is not present on line 16 and a pulse is present on line 18 from the divider 15 the AND gate 14 will provide a signal on line 19 which switches on the test transponder 3 for a period of 20 m.secs.
Pulses from the divider 15 at five sec.
intervals are also fed via line 20 to a further AND gate 21 which is also fed with signals from line 16 when an incoming carrier signal is present. In the presence of an incoming carrier signal from the transponder 1 the test transponder 3 will not be switched on by a signal on line 19 but an output signal will obtain on line 22 from the AND gate 21 which is effective to initiate a test cycle in the error checking apparatus 11. Thus, when the interrogator is carried in a vehicle which stops over a transponder, the test transponder will be inhibited and an error checking cycle will be repeated every 5 seconds utilising signals from the track side transponder 1.
When a test cycle whether it be performed on the signal originating from the trackside transponder 1 or the test transponder 3 is successful an output signal will be fed on line 13 from the error checking apparatus 11 to a monostable circuit 23 and in the event that the monostable circuit does not receive an input for 12.5 seconds an output signal will be fed to a failure indicator 24 which provides a warning and indicates that the receiver has failed. By providing a 12.5 second delay which is two and a half times the interval between test transmissions, failure or apparent failure due to the arrival of the vehicle adjacent a trackside transponder or failure of recycled track side transponder messages due to the vehicle leaving the vicinity of the track side transponder will not cause a failure to be indicated.
In order to allow for the situation which obtains when incoming signals from the trackside transponder 1 are received as the test transponder 3 is switched on, further inhibit means are provided comprising gates (not shown) which are effective to switch off the test transponder if a valid input signal is not received within 6 milli seconds of the start of transmission from the test transponder 3. Thus if a garbled message is received due to the contemporaneous reception of signals from the test transponder and from the trackside transponder the test transponder will be switched off after 6 milli-seconds.
By utilising a system as just before described wherein the interrogator and test transponder are mounted on a vehicle which runs along a track and in which a number of transponders such as the transponder 1 are associated with the track, a particularly safe system may be afforded wherein failure of the receiver apparatus is quickly indicated.
In order also to indicate failure of a trackside transponder each transponder may have associated with it a magnet which operates a switch not shown carried by the vehicle borne interrogator. If closure of the switch is not followed by a transmission from the trackside transponder then a fault in the trackside transponder is indicated.
It is specially envisaged that a system similar to or corresponding to the interrogator/transponder system as just before described, may be used in an automatic control system.
Various modifications may be made to the arrangements shown without departing from the scope of the invention and for example it will be appreciated that although the interrogator described is carried in a vehicle the position of the interrogator and transponder may be reversed and the interrogator may be mounted trackside and the transponder carried on a vehicle or indeed any other moving object as for identification purposes. The interrogator may be mounted on a vehicle with an aerial beneath the vehicle. Alternative configurations allow for the transponder aerial to be mounted in the roof of the vehicle and the interrogator aerial to be suspended from an overhead gentry or tunnel roof. The test transmitter which is in effect, a transponder transmitting at lower power than track beacons, may be incorporated in the aerial assembly.The message structure used by the test transmitter may be the same as that from the track beacons and is subjected to the same validity and coding checks. Normally four full messages are required for a majority circuit to operate. If after approximateley six message lengths have elapsed no message has been decoded correctly the test transmitter is switched off and the test is regarded as a failure as just before described.
WHAT WE CLAIM IS: 1. A transponder/interrogator system wherein the interrogator comprises a receiver including means for checking the validity of the received signal, a test transmitter arranged to transmit test signals at intervals to the receiver of the interrogator, inhibit means for inhibiting transmission from the test transmitter when the interrogator receives a signal indicating that the transponder is in the vicinity, an indicator for providing a warning signal, and delay means effective to permit operation of the indicator if valid signals are not received by the receiver for a period determined by the said delay means, said period being longer than the said interval between test signals transmissions transmitted by the test transmitter.
2. A transponder/interrogator system as claimed in claim 1 wherein the transponder is operatively associated with a vehicle and the interrogator is stationary.
3. A transponder/interrogator system as claimed in claim 1 wherein the interrogator is operatively associated with a vehicle and the transponder is stationary.
4. A transponder/interrogator system as claimed in any preceeding claim wherein the signal indicating that the transponder is in the same vicinity as the interrogator is provided by switch means operated when a mobile part of the system carrying the transponder or the interrogator as the case may be is in a predetermined location.
5. A transponder/interrogator system as claimed in any of claims 1 to 3 wherein the signal indicating that the transponder is in the same vicinity as the interrogator is provided by the transponder transmitter.
6. A transponder/interrogator system as claimed in any preceeding claim wherein the interrogator includes means for radiating energy which is received by the transponder and utilised to provide power for it's transmitter.
7. A transponder/interrogator system as claimed in any preceeding claim wherein the transmitter of the transponder is arranged to transmit at a frequency which is a submultiple of the frequency at which energy is transmitted to the interrogator.
8. A transponder/interrogator system as claimed in any preceeding claim wherein the interrogator includes an oscillator for providing a signal to provide power for the transponder and divider means responsive to the oscillator for providing at the said intervals trigger signals which are fed to the test transmitter to initiate the said test signal transmission.
9. A transponder/interrogator system as claimed in claim 8 wherein the inhibit means comprises a gate responsive to a signal received by the receiver for inhibiting said trigger signals whereby the test transmitter is not switched on when signals are being received from the transponder.
10. A transponder/interrogator system as claimed in claim 8 or claim 9 wherein further gating means are provided responsive in the presence of a received carrier signal and said trigger signal for initiating a validity checking cycle utilising a signal received from the transponder when the test transmitter is inhibited.
11. A transponder/interrogator system as claimed in any preceding claim wherein further inhibit means are provided responsive to the means of checking the validity of the received signal for switching off the test transmitter if a signal of predetermined character is not detected after the test transmitter has been on for a predetermined time.
12. A transponder/interrogator system substantially as hereinbefore described with reference to the drawing accompanying the Provisional Specification.
13. A transponder/interrogator system as claimed in any preceeding claim wherein the interrogator is carried by a vehicle for use on a track or rail and one or more transponders are situated along the rail or track.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (13)

**WARNING** start of CLMS field may overlap end of DESC **. similar to or corresponding to the interrogator/transponder system as just before described, may be used in an automatic control system. Various modifications may be made to the arrangements shown without departing from the scope of the invention and for example it will be appreciated that although the interrogator described is carried in a vehicle the position of the interrogator and transponder may be reversed and the interrogator may be mounted trackside and the transponder carried on a vehicle or indeed any other moving object as for identification purposes. The interrogator may be mounted on a vehicle with an aerial beneath the vehicle. Alternative configurations allow for the transponder aerial to be mounted in the roof of the vehicle and the interrogator aerial to be suspended from an overhead gentry or tunnel roof. The test transmitter which is in effect, a transponder transmitting at lower power than track beacons, may be incorporated in the aerial assembly.The message structure used by the test transmitter may be the same as that from the track beacons and is subjected to the same validity and coding checks. Normally four full messages are required for a majority circuit to operate. If after approximateley six message lengths have elapsed no message has been decoded correctly the test transmitter is switched off and the test is regarded as a failure as just before described. WHAT WE CLAIM IS:
1. A transponder/interrogator system wherein the interrogator comprises a receiver including means for checking the validity of the received signal, a test transmitter arranged to transmit test signals at intervals to the receiver of the interrogator, inhibit means for inhibiting transmission from the test transmitter when the interrogator receives a signal indicating that the transponder is in the vicinity, an indicator for providing a warning signal, and delay means effective to permit operation of the indicator if valid signals are not received by the receiver for a period determined by the said delay means, said period being longer than the said interval between test signals transmissions transmitted by the test transmitter.
2. A transponder/interrogator system as claimed in claim 1 wherein the transponder is operatively associated with a vehicle and the interrogator is stationary.
3. A transponder/interrogator system as claimed in claim 1 wherein the interrogator is operatively associated with a vehicle and the transponder is stationary.
4. A transponder/interrogator system as claimed in any preceeding claim wherein the signal indicating that the transponder is in the same vicinity as the interrogator is provided by switch means operated when a mobile part of the system carrying the transponder or the interrogator as the case may be is in a predetermined location.
5. A transponder/interrogator system as claimed in any of claims 1 to 3 wherein the signal indicating that the transponder is in the same vicinity as the interrogator is provided by the transponder transmitter.
6. A transponder/interrogator system as claimed in any preceeding claim wherein the interrogator includes means for radiating energy which is received by the transponder and utilised to provide power for it's transmitter.
7. A transponder/interrogator system as claimed in any preceeding claim wherein the transmitter of the transponder is arranged to transmit at a frequency which is a submultiple of the frequency at which energy is transmitted to the interrogator.
8. A transponder/interrogator system as claimed in any preceeding claim wherein the interrogator includes an oscillator for providing a signal to provide power for the transponder and divider means responsive to the oscillator for providing at the said intervals trigger signals which are fed to the test transmitter to initiate the said test signal transmission.
9. A transponder/interrogator system as claimed in claim 8 wherein the inhibit means comprises a gate responsive to a signal received by the receiver for inhibiting said trigger signals whereby the test transmitter is not switched on when signals are being received from the transponder.
10. A transponder/interrogator system as claimed in claim 8 or claim 9 wherein further gating means are provided responsive in the presence of a received carrier signal and said trigger signal for initiating a validity checking cycle utilising a signal received from the transponder when the test transmitter is inhibited.
11. A transponder/interrogator system as claimed in any preceding claim wherein further inhibit means are provided responsive to the means of checking the validity of the received signal for switching off the test transmitter if a signal of predetermined character is not detected after the test transmitter has been on for a predetermined time.
12. A transponder/interrogator system substantially as hereinbefore described with reference to the drawing accompanying the Provisional Specification.
13. A transponder/interrogator system as claimed in any preceeding claim wherein the interrogator is carried by a vehicle for use on a track or rail and one or more transponders are situated along the rail or track.
GB5997/77A 1977-02-12 1977-02-12 Transponder/interrogator systems Expired GB1594231A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB5997/77A GB1594231A (en) 1977-02-12 1977-02-12 Transponder/interrogator systems

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB5997/77A GB1594231A (en) 1977-02-12 1977-02-12 Transponder/interrogator systems

Publications (1)

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GB1594231A true GB1594231A (en) 1981-07-30

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0223961A1 (en) * 1985-11-22 1987-06-03 AlliedSignal Inc. Interrogator and transponder test equipment
EP0389343A1 (en) * 1989-03-21 1990-09-26 Thomson-Csf Method for the remote monitoring of antenna elements in a secondary radar, and device for carrying out the process
EP0632289A2 (en) * 1993-06-30 1995-01-04 Mitsubishi Denki Kabushiki Kaisha Search and rescue radar transponder
EP0634728A2 (en) * 1993-07-01 1995-01-18 Edward Van Geel Non-contact reader

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0223961A1 (en) * 1985-11-22 1987-06-03 AlliedSignal Inc. Interrogator and transponder test equipment
EP0389343A1 (en) * 1989-03-21 1990-09-26 Thomson-Csf Method for the remote monitoring of antenna elements in a secondary radar, and device for carrying out the process
FR2644898A1 (en) * 1989-03-21 1990-09-28 Thomson Csf METHOD FOR REMOTE MONITORING OF RADIANT ELEMENTS OF ANTENNA OF A SECONDARY SURVEILLANCE RADAR AND DEVICE FOR ITS IMPLEMENTATION
EP0632289A2 (en) * 1993-06-30 1995-01-04 Mitsubishi Denki Kabushiki Kaisha Search and rescue radar transponder
EP0632289A3 (en) * 1993-06-30 1996-07-17 Mitsubishi Electric Corp Search and rescue radar transponder.
EP0634728A2 (en) * 1993-07-01 1995-01-18 Edward Van Geel Non-contact reader
EP0634728A3 (en) * 1993-07-01 1996-08-28 Geel Edward Van Non-contact reader.
US5587574A (en) * 1993-07-01 1996-12-24 Van Geel; Edward Non-contact reader

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Legal Events

Date Code Title Description
PS Patent sealed [section 19, patents act 1949]
732 Registration of transactions, instruments or events in the register (sect. 32/1977)
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19940110