Proximity measuring apparatus

• US 6,614,387 B1
• Filed: 02/21/2001
• Issued: 09/02/2003
• Est. Priority Date: 09/29/1998
• Status: Expired due to Fees

• Current Assignee: Qinetiq Limited (QinetiQ Group PLC)
• Original Assignee: Qinetiq Limited (QinetiQ Group PLC)
• Inventors: Deadman, Harry A
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US09/763,326
• Time in Patent Office: 923 Days
• Field of Search: 342/70, 342/71, 342/72, 342/42, 342/44, 342/46, 342/47, 342/51, 342/118, 342/125, 342/131, 342/132, 342/134, 342/135, 342/145, 342/189, 342/195, 340/435, 340/436, 340/903, 701/301
• US Class Current: 342/70
• CPC Class Codes: G01S 13/325 using transmission of coded signals, e.g. P.S.K. signals
• CPC Class Codes: G01S 13/825 with exchange of information between interrogator and responder
• CPC Class Codes: G08G 1/163 involving continuous checking
• CPC Class Codes: H04J 13/0029 Gold
• CPC Class Codes: H04J 13/107 by concatenation

Abstract

A proximity measuring apparatus (70) comprises an interrogator (80) for generating an interrogation signal encoded with a reference signature code comprising concatenated codes and emitting it as interrogating radiation. It also incorporates a transponder (90) for receiving the interrogating radiation, demodulating it to extract its signature code and then remodulating it after a delay period to provide a signal for reemission as return radiation therefrom. The interrogator (80) receives return radiation at its antenna (260) and demodulates it to extract its signature code and then correlates the code with the reference code to determine mutual correlation thereof. The interrogator (80) incorporates a computer (290) for controlling a scan direction of the antenna (260) and for measuring time delay between emission of the interrogating radiation therefrom and receipt of corresponding return radiation. The computer (290) computes distance and relative bearing of a transponder (90) providing the return radiation from the scan direction and the time delay. The apparatus (70) may be used for improving road vehicle safety.

Claims

1. A proximity measuring apparatus incorporating:

(a) transponding means for receiving interrogating radiation and emitting return radiation in response thereto;

(b) interrogating means for generating and emitting the interrogating radiation and for receiving the return radiation for determining proximity of the interrogating means relative to the transponding means;

(c) the interrogating means is adapted to encode the interrogating radiation with a signature code comprising a plurality of concatenated data sequences; and

(d) the transponding means is adapted to receive the interrogating radiation, and to encode the return radiation with the signature code, thereby enabling the interrogating means to associate the interrogating radiation with the return radiation.

2. An apparatus according to claim 1 wherein the concatenated data sequences incorporate concatenated pseudo-random data sequences.

3. An apparatus according to claim 1 wherein the concatenated data sequences incorporate concatenated Gold code data sequences.

4. An apparatus according to claim 1, wherein the interrogating means incorporates correlating means for correlating the signature code encoded into the interrogating radiation with a signature code encoded into return radiation received thereat, thereby enabling it to associate the interrogating radiation with its corresponding return radiation.

5. An apparatus according to claim 1, wherein the transponding means is adapted to emit the return radiation at a frequency which is substantially different to that of the interrogating radiation received thereat, thereby enabling the interrogating means to discriminate between passive reflections of the interrogating radiation and the return radiation.

6. An apparatus according to claim 1, wherein:

(i) the transponding means (9) is arranged to emit the return signal as the return radiation after a time delay period from receipt of the interrogating radiation, said time delay period being greater than a time required for the interrogating radiation to propagate from the interrogating means to be passively reflected and re-received at more than a preset threshold intensity thereat; and

(ii) the interrogating means is adapted to discriminate between reception of delayed and un-delayed return radiation.

8. An apparatus according to claim 1, wherein the interrogating means incorporates computing means for determining a distance of the transponding means relative thereto, said computing means adapted to record an interval of time between emission of the interrogating radiation from said interrogating means and receipt of corresponding return radiation thereat, said computing means adapted to calculate said distance using said interval of time.

9. An apparatus according to claim 8, wherein the apparatus incorporates warning means in communication with the computing means, said computing means adapted to monitor position of the transponding means relative thereto, and to activate said warning means to provide a warning alarm when there is a risk of collision of said transponding means with said interrogating means.

10. An apparatus according to claim 8, wherein the computing means is adapted to monitor position of the transponding means relative to the interrogating means and activate braking means to modify a trajectory of said interrogating means for collision avoidance when there is a risk of collision of said transponding means with said interrogating means.

11. An apparatus according to claim 1, wherein the interrogating means is adapted to vary its time interval duration between successive emissions of interrogating radiation therefrom.

12. An apparatus according to claim 11, wherein the interrogating means is arranged to vary the time intervals in multiples of a time step, said multiples altering pseudo-randomly.

13. An apparatus according to claim 1, wherein the transponding means incorporates sensing means for sensing at least one of acceleration, speed and orientation of said transponding means, for providing data thereto, and the transponding means is adapted to encode said data onto the return radiation (Rout).

14. A vehicle incorporating the apparatus according to claim 1, wherein said vehicle incorporates said interrogating means in a frontal region thereof and said transponding means in a rear region thereof.

15. An elongate vehicle incorporating the apparatus according to claim 1, wherein said vehicle incorporates said interrogating means in a frontal region thereof and said transponding means in a rear region and side regions thereof, said side regions spatially situated substantially between said frontal region and said rear region.

7. A proximity measuring apparatus incorporating:

(a) transponding means for receiving interrogating radiation and emitting return radiation in response thereto;

(b) interrogating means for generating and emitting the interrogating radiation and for receiving the return radiation for determining proximity of the interrogating means relative to the transponding means;

(c) the interrogating means is adapted to encode the interrogating radiation with a signature code comprising a plurality of concatenated data sequences;

(d) the transponding means is adapted to receive the interrogating radiation, and to encode the return radiation with the signature code,

thereby enabling the interrogating means to associate the interrogating radiation with the return radiation, wherein the interrogating means incorporates;

(i) an antenna for emitting the interrogating radiation and receiving the return radiation, said antenna having a directional gain response comprising a direction of enhanced gain relative thereto;

(ii) scanning means for angularly scanning said antennae; and

(iii) computing means for controlling the scanning means and determining direction of the transponding means relative to the interrogating means from scan direction of said antenna in which the return radiation is received.

16. A method of measuring proximity in a proximity measuring apparatus, the apparatus including an interrogator and a transponder, the method comprising the steps of:

(a) generating and emitting interrogating radiation from the interrogator, said radiation incorporating a signature code comprising a plurality of concatenated data sequences;

(b) receiving the interrogating radiation at the transponder and generating a receive signal in response thereto;

(c) storing the receive signal;

(d) generating a return signal in response to the receive signal, said return signal encoded with the signature code;

(e) emitting the return signal after a time delay period from receipt of the interrogating radiation;

(f) receiving the return radiation at the interrogator;

(g) correlating the signature code encoded into the interrogating radiation with the signature code encoded into the return radiation for associating the return radiation with the interrogating radiation; and

(h) calculating at the interrogator proximity of the transponder relative thereto from propagation direction of the return radiation relative to the interrogator and time interval between emission of the interrogating radiation and receipt of the return radiation.

17. A method according to claim 16, wherein the concatenated data sequences incorporate concatenated pseudo-random data sequences.

18. A method according to claim 16, wherein the concatenated data sequences incorporate concatenated Gold code data sequences.