Security system

• US 6,937,136 B2
• Filed: 09/18/2001
• Issued: 08/30/2005
• Est. Priority Date: 09/19/2000
• Status: Expired due to Term

• Current Assignee: Jaguar Land Rover Limited (TATA Motors Limited), Rover Group Limited (Techtronic 2000 Plc)
• Original Assignee: Land Rover (TATA Motors Limited)
• Inventors: Talbot, Kevin Trevor, Bottomley, Christopher Richard, Greenwood, Jeremy John
• Primary Examiner(s): Holloway, III, Edwin C.
• Application Number:
  US09/954,765
• Publication Number:
  US 20020033752A1
• Time in Patent Office: 1,442 Days
• Field of Search: 340/5.61, 340/5.62, 340/5.63, 340/5.64, 340/10.1, 307/10.5
• US Class Current: 340/5.61
• CPC Class Codes: B60R 25/246 characterised by the challenge triggering
• CPC Class Codes: G07C 2009/00396 starting with prompting the keyless data carrier
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 2209/65 using means for sensing the user's hand
• CPC Class Codes: G07C 9/00309 operated with bidirectional data transmission between data carrier and locks
• CPC Class Codes: H01Q 1/2225 used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/3233 particular used as part of a sensor or in a security system, e.g. for automotive radar, navigation systems
• CPC Class Codes: H01Q 1/3266 using the mirror of the vehicle
• CPC Class Codes: H01Q 1/3283 side-mounted antennas, e.g. bumper-mounted, door-mounted mounted on windscreens H01Q1/1271
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 21/29 Combinations of different interacting antenna units for giving a desired directional characteristic H01Q25/00 takes precedence
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H04L 2209/84 Vehicles
• CPC Class Codes: H04L 9/0875 based on channel impulse response [CIR]
• CPC Class Codes: H04L 9/3271 using challenge-response
• CPC Class Codes: H04W 12/06 Authentication
• CPC Class Codes: H04W 4/40 for vehicles, e.g. vehicle-to-pedestrians [V2P]

Abstract

A security system is disclosed which is suitable for use in a passive entry and passive starting arrangement for a vehicle 10. A set of transmitters in the form of coils A, B, C are spaced around the vehicle 10, one A, B in each door mirror 20R, 20L and one in a high level brake light 16 at the rear end.

Operation of a door handle initiates an access challenge from the vehicle 10 which is sent out successively on a plurality of the coils A, B, C. A portable transponder 26 carried by an authorised user is adapted to pick up the challenge signal and send back to a security controller 18 a response signal in which is included vector information relating to the relative positioning between the vehicle 10 and the transponder 26.

Claims

1. A security system for a protected object, the system comprising

a security controller and a plurality of signal transmitters associated with the protected object, and

a portable transponder, arranged in use to receive a challenge signal, from said transmitters and to transmit in response signal in response thereto,

wherein the challange signal comprises vector information relating to the direction of a magnetic field generated by each of said transmitters and wherein comparator means are provided for carrying out a comparison between said vector information and a vector map of an area associated with the protected object to determine the position of the transponder in relation to the protected object and wherein the security controller is arranged to perform a security function depending on the comparison.

2. The security system according to claim 1, wherein the vector information comprises the relative directions of at least a component of the signals from the respective transmitters.

3. The security system according to claim 1, wherein the vector information comprises the relative strengths of at least a component of the signals form the respective transmitters.

4. The security system according to claim 1, wherein the transponder is arranged to relay said vector information to the security controller and the security controller is arranged to determine from the vector information the position of the transponder in relation to the protected object.

5. The security system according to claim 1, wherein the transponder is arranged to determine from the vector information its position in relation to the protected object and to vary its response accordingly.

6. The security system according to claim 1, wherein the transmitters are arranged in groups, each group comprising at least two transmitters (A1, A2) located substantially together in different orientations.

7. The security system according to claim 1, wherein the challenge signal comprises a plurality of components from different transmitters and the relative strengths of the components within the signal is arranged to vary with time during transmission of the challenge signal.

8. The signal system according to claim 1, wherein the transponder comprises a plurality of sensors arranged to detect different components of the challenge signal.

9. The security system according to claim 8, wherein said components are substantially mutually orthogonal.

10. The security system according to claim 8, wherein the transponder further comprises a calibration transmitter arranged to transmit a signal at a known orientation relative to said sensors so as to enable calibration of the sensors.

11. The security system according to claim 1, wherein the object is a vehicle and the security function comprises allowing access to the vehicle.

12. The security system according to claim 11, further comprising a plurality of sensors each associated with respective closure of the vehicle, the security controller is arranged to issue the challenge signal is response to an attempt by a user to open one of the closures.

13. The system according to claim 1, wherein the object is a vehicle and the security function comprises enabling the vehicle to start.

14. A security system for a protected object, the security system comprising:

a plurality of signal transmitters and

a security controller

associated with the protected object,

the security controller directing the transmitters to transmit a plurality of corresponding challenge signals, and

a portable transponder, including

a plurality of orthogonally oriented and directionally sensitive sensors for receiving each of the challenge signals and detecting a corresponding plurality of vector components of each challenge signal,

the transponder operating in response to each challenge signal for

extracting the vector components of the challenge signal and

transmitting the vector components of each challenge signal to the security controller in a corresponding response signal,

the security controller being response to each response signal for

determining a corresponding vector between the transponder and the signal transmitter of the corresponding challenge signal, and

determining from the vectors the position of the transponder with respect to the signal transmitters.

15. The security system according to claim 14, wherein the vector components comprise the relative strengths of the challenge signals along a plurality of axes defined by the orthogonally oriented sensors.

16. The security system according to claim 14, wherein the transmitters are arranged in groups, each group comprising at least two transmitters (A1, A2) located substantially together in different orientations.

17. The security system according to claim 14, wherein the challenge signal comprises a plurality of components from different transmitters and the relative strengths of the components within the signal is arranged to vary with time during transmission of the challenge signal.

18. The security system according to claim 14, wherein the transponder further comprises a calibration transmitter arranged to transmit a signal at a known orientation relative to said sensors so as to enable calibration of the sensors.

19. The security system according to claim 14, wherein the object is a vehicle and the security function comprises allowing access to the vehicle.

20. The security system according to claim 14 further comprising a plurality of sensors each associated with respective closure of the vehicle, the security controller is arranged to issue the challenge signal is response to an attempt by a user to open one of the closures.

21. The system according to claim 14, wherein the object is a vehicle and the security function comprises enabling the vehicle to start.