Bi-static radar system

• US 10,641,881 B2
• Filed: 07/07/2016
• Issued: 05/05/2020
• Est. Priority Date: 08/28/2015
• Status: Active Grant

• Current Assignee: Aptiv Technologies AG
• Original Assignee: Aptiv Technologies Limited (BorgWarner Incorporated)
• Inventors: Searcy, James F., Rossiter, Ryan K., Alland, Stephen W.
• Primary Examiner(s): Brainard, Timothy A
• Application Number:
  US15/204,056
• Publication Number:
  US 20180024233A1
• Time in Patent Office: 1,398 Days
• Field of Search: 342125
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 7/006 using shared front-end circuitry, e.g. antennas G01S13/765, G01S13/825 take precedence
• CPC Class Codes: G01S 7/032 Constructional details for solid-state radar subsystems
• CPC Class Codes: G01S 7/4008 of transmitters

Abstract

A bi-static radar system configured for coherent detection of a radar-signal includes a plurality of radar-transceivers, a controller, and a communications device. The plurality of radar-transceivers is characterized as physically spaced apart with respect to each other. The controller is in communication with the each of the radar-transceivers and is configured to coherently operate each of the radar-transceivers. The communications device communicates both a reference-clock signal and a frame-sync signal from the controller to each of the plurality of radar-transceivers whereby the plurality of radar-transceivers operate coherently. Alternatively, the system may include a reference-signal generator, a transmitter, and a plurality of receivers. The reference-signal generator generates a reference-signal characterized by a reference-frequency proportional to a fraction of a radar-frequency of a radar-signal transmitted. The transmitter generates the radar-signal at the radar-frequency based on the reference-signal. The plurality of receivers operates coherently to detect the radar-signal based on the reference-signal.

Claims

1. A bi-static radar system configured for coherent detection of a radar-signal, said system comprising:

a reference clock generator operable to generate a common reference clock signal at a reference-frequency;

a plurality of receiver modules; and

at least one fractional-N PLL associated with each of the plurality of receiver modules;

wherein

each fractional-N PLL is configured to generate a local clock signal independently for the respective receiver module based on the common reference clock signal, such that the bi-static radar system is operable to coherently detect a radar signal.

2. The system in accordance with claim 1, wherein the plurality of receiver modules includes a first receiver module and a second receiver module spaced apart from the first receiver.

3. The system in accordance with claim 2, wherein the first receiver module is spaced apart from the second receiver module by more than five-hundred-millimeters (500 mm).

4. The system in accordance with claim 1, wherein each fractional-N phase-lock-loop generates a local-oscillator signal at the radar-frequency based on the common reference clock signal.

5. The system in accordance with claim 4, wherein the local-oscillator signal used to coherently detect the radar-signal by the plurality of receivers.

6. The system in accordance with claim 1, wherein the system comprises:

a plurality of transmitters, each one of the plurality of transmitters is associated with one of the plurality of receiver modules to form a plurality of radar-transceivers.

7. The system in accordance with claim 6, wherein each of the plurality of radar-transceivers includes a fractional-N phase-lock-loop.

8. The system in accordance with claim 7, wherein each fractional-N phase-lock-loop generates the radar-signal at the radar-frequency based on the common reference clock signal.

9. The system in accordance with claim 7, wherein each fractional-N phase-lock-loop generates a local-oscillator signal at the radar-frequency based on the common reference clock signal.

10. The system in accordance with claim 9, wherein the local-oscillator signal is used to coherently detect the radar-signal.

11. The system in accordance with claim 7, wherein each fractional-N phase-lock-loop:

generates the radar-signal at the radar-frequency based on the common reference clock signal; and

generates a local oscillator-signal at the radar-frequency based on the common reference clock signal, said local-oscillator signal used to coherently detect the radar-signal.

12. The system in accordance with claim 6, wherein the system comprises a plurality of serializer/deserializer chipset pairs used to communicate the common reference clock signal to each of the plurality of radar-transceivers.

13. The system in accordance with claim 6, wherein the common reference clock signal is output by one of the of the plurality of radar-transceivers and communicated to the remainder of the plurality of radar-transceivers.

14. The system in accordance with claim 1, further comprising:

a frame sync signal distributed to each fractional-N PLL.

15. The system in accordance with claim 14, wherein each fractional-N PLL uses the frame sync signal to trigger at least one modulation sequence.

16. The system of claim 1, wherein each of the plurality of receiver modules is a transceiver module that includes a transmitter.

17. The system of claim 16, wherein each fractional-N PLL is configured to generate a clock signal independently for the transmitter of the respective transceiver module.

18. A method, comprising:

generating, using a reference clock generator, a common reference clock signal at a reference-frequency; and

coherently detecting, using a plurality of receiver modules each associated with at least one fractional-N PLL, a radar-signal based on the common reference clock signal;

wherein

each fractional-N PLL is configured to generate a local clock signal independently for the respective receiver module based on the common reference clock signal, such that the bi-static radar system is operable to coherently detect a radar signal.