Systems and methods for determining a position of a transmitter of a bistatic radar system

Patent metadata

Field	Value
Publication number	US-9709662-B2
Application number	US-201414461579-A
Country	US
Kind code	B2
Filing date	Aug 18, 2014
Priority date	Aug 18, 2014
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A bistatic radar system may include a transmitter, a target at a first known position, a receiver at a second known position, and a transmitter position determination unit. The receiver is configured to receive one or more reflected radar signals transmitted from the transmitter and reflected off the target. The receiver is configured to receive one or more direct radar signals transmitted from the transmitter. The transmitter position determination unit is configured to determine a position of the transmitter based on a determination of a distance between the first and second known positions and a determination of a first angular difference between the reflected radar signal(s) and the direct radar signal(s) that are received by the receiver.

First claim

What is claimed is:

1. A bistatic radar system comprising:
a transmitter;
a target at a first known position;
a receiver at a second known position, wherein the receiver is configured to receive one or more reflected radar signals transmitted from the transmitter and reflected off the target, and wherein the receiver is configured to receive one or more direct radar signals transmitted from the transmitter; and
a transmitter position determination unit configured to determine a position of the transmitter based on a determination of a distance between the first and second known positions and a determination of a first angular difference between the one or more reflected radar signals and the one or more direct radar signals that are received by the receiver.

2. The bistatic radar system of claim 1 , wherein the transmitter refrains from communicating the position of the transmitter.

3. The bistatic radar system of claim 1 , wherein the receiver includes the transmitter position determination unit.

4. The bistatic radar system of claim 1 , wherein the transmitter position determination unit is configured to determine a bistatic range difference by measuring a time difference between a first time (T 1 ) when the one or more reflected radar signals or the one or more direct radar signals are received by the receiver and a second time (T 2 ) when the other of the one or more reflected radar signals or the one or more direct radar signals are received by the receiver.

5. The bistatic radar system of claim 4 , wherein the transmitter position determination unit is configured to convert the time difference to the bistatic range difference by multiplying the time difference by the speed of light.

6. The bistatic radar system of claim 4 , wherein the transmitter is separated from the target by a first linear distance (S 1 ), the transmitter is separated from the receiver by a second linear distance (S 2 ), and the receiver is separated from the transmitter by a third linear distance (S 3 ), wherein the transmitter position determination unit is configured to relate the first, second, and third distances to the first and second times as S 1 +S 2 −S 3 =C*(T 1 −T 2 ), wherein C is the speed of light.

7. The bistatic radar system of claim 6 , wherein the transmitter position determination unit is configured to determine K=S 1 −S 3 , such that K=C*(T 1 −T 2 )−S 2 .

8. The bistatic radar system of claim 7 , wherein the transmitter position determination unit is configured to determine the third distance as S 3 =(S 2 2 −K 2 )/(2S 2 cos θ 1 +2K).

9. The bistatic radar system of claim 1 , wherein the transmitter position determination unit is configured to determine a second angular difference between a main beam transmitted from the transmitter towards the target and a sidelobe transmitted from the transmitter toward the receiver, and wherein the transmitter position determination unit uses the second angular difference to determine an accuracy of the determined position of the transmitter.

10. The bistatic radar system of claim 1 , wherein the transmitter position determination unit is configured to determine one or both of a first elevation of the transmitter relative to the receiver or a second elevation of the target relative to the receiver.

11. The bistatic radar system of claim 1 , wherein each of the transmitter, the target, and the target are moving or fixed in position.

12. A bistatic radar method comprising:
providing target position data indicative of a first position of a target to a transmitter position determination unit;
providing receiver position data indicative of a second position of a receiver to the transmitter position determination unit;
receiving, with the receiver, one or more reflected radar signals transmitted from a transmitter and reflected off the target;
receiving, with the receiver, one or more direct radar signals transmitted from the transmitter; and
determining a third position of the transmitter, with the transmitter position determination unit, based on a distance between the first and second positions and a first angular difference between the one or more reflected radar signals and the one or more direct radar signals.

13. The bistatic radar method of claim 12 , further comprising refraining from communicating the third position data from the transmitter.

14. The bistatic radar method of claim 12 , wherein the determining a third position comprises determining a bistatic range difference by measuring a time difference between a first time (T 1 ) when the one or more reflected radar signals or the one or more direct radar signals are received by the receiver and a second time (T 2 ) when the other of the one or more reflected radar signals or the one or more direct radar signals are received by the receiver.

15. The bistatic radar method of claim 14 , wherein the determining a third position further comprises converting the time difference to the bistatic range difference by multiplying the time difference by the speed of light.

16. The bistatic radar method of claim 14 , wherein the transmitter is separated from the target by a first linear distance (S 1 ), the transmitter is separated from the receiver by a second linear distance (S 2 ), and the receiver is separated from the transmitter by a third linear distance (S 3 ), wherein the determining a third position further comprises relating the first, second, and third distances to the first and second times as S 1 +S 2 −S 3 =C*(T 1 −T 2 ), wherein C is the speed of light.

17. The bistatic radar method of claim 16 , wherein the determining a third position further comprises:
determining K=S 1 −S 3 , such that K=C*(T 1 −T 2 )−S 2 ; and
determining S 3 =(S 2 2 −K 2 )/(2S 2 cos θ 1 +2K).

18. The bistatic radar method of claim 12 , further comprising:
determining a second angular difference between a main beam transmitted from the transmitter towards the target and a sidelobe transmitted from the transmitter toward the receiver,
using the second angular difference to determine an accuracy of the determined position of the transmitter.

19. The bistatic radar method of claim 12 , further comprising determining one or both of a first elevation of the transmitter relative to the receiver or a second elevation of the target relative to the receiver.

20. A bistatic radar system comprising:
a transmitter position determination unit configured to determine a position of a transmitter based on a determination of a distance between first and second known positions of a target and a receiver, respectively, and a determination of a first angular difference between (a) one or more reflected radar signals reflected off the reflector and received by the receiver and (b) one or more direct radar signals directly received by the receiver.

21. The bistatic radar system of claim 20 , wherein the transmitter position determination unit is configured to determine a bistatic range difference by measuring a time difference between a first time (T 1 ) when the one or more reflected radar signals or the one or more direct radar signals are received by the receiver and a second time (T 2 ) when the other of the one or more reflected radar signals or the one or more direct radar signals are received by the receiver,
wherein the transmitter is separated from the target by a first linear distance (S 1 ), the transmitter is separated from the receiver by a second linear distance (S 2 ), and the receiver is separated from the transmitter by a th

Assignees

• Boeing Co

Inventors

• Baker James Bryan
• Ray Gary Alan

Classifications

• G01S13/003 Primary

  Bistatic radar systems; Multistatic radar systems · CPC title

• G01S5/0273 Primary

  using multipath or indirect path propagation signals in position determination · CPC title

• G01S3/02

  using radio waves · CPC title

• G01S5/06

  Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements (G01S5/12 takes precedence) · CPC title

• G01S5/02 Primary

  using radio waves (using satellite radio beacon systems for determining position G01S19/00) · CPC title