ADS-B radar system

• US 7,414,567 B2
• Filed: 12/22/2006
• Issued: 08/19/2008
• Est. Priority Date: 12/22/2006
• Status: Active Grant

• Current Assignee: Bluehalo Labs LLC
• Original Assignee: Intelligent Automation, Inc.
• Inventors: Zhang, Yan, Qiao, Jinglu
• Primary Examiner(s): Sotomayor; John B
• Application Number:
  US11/644,422
• Publication Number:
  US 20080150784A1
• Time in Patent Office: 606 Days
• Field of Search: 342/21, 342 29- 40, 342/42, 342/46, 342/51, 342/90, 342/133, 342/139, 342/140, 342/146, 342/192, 342/194, 342/195
• US Class Current: 342/29
• CPC Class Codes: G01S 13/781 Secondary Surveillance Radar [SSR] in general
• CPC Class Codes: G01S 13/86 Combinations of radar systems with non-radar systems, e.g. sonar, direction finder
• CPC Class Codes: G01S 13/933 of aircraft or spacecraft
• CPC Class Codes: G01S 7/006 using shared front-end circuitry, e.g. antennas G01S13/765, G01S13/825 take precedence

Abstract

A system and method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system, wherein the method includes the steps of providing a standard ADS-B transmitter and encoder, a phase modulator including a digital synthesizer, radio-frequency electronics, antennas, and a radar transceiver; synthesizing digital-based band signals from the ADS-B transmitter with additional random phase modulation using the digital synthesizer; using the antennas to both transmit and receive signals; and estimating angles-of-arrival for every target in a field-of-view. The method may include the steps of demodulating the signals received by the antennas, providing a digital signal processor, and performing matched filtering on received signals. The method may also include the step of estimating a target range of identified targets using the digital signal processor.

Claims

1. An airborne radar system to assist with collision avoidance, the radar system comprising:

a standard ADS-B transmitter and encoder;

a phase modulator including a digital synthesizer;

radio-frequency electronics containing an up and down conversion, amplification and filtering capabilities;

antennas; and

a radar transceiver that controls the phase modulation of an ADS-B waveform and implements real-time target detection and tracking.

2. The airborne radar system as set forth in claim 1, wherein said phase modulator adds a phase shift to a standard ADS-B signal with a baseband digital synthesizer.

3. The airborne radar system as set forth in claim 2, wherein said phase modulator up converts a baseband analog waveform containing both I and Q channels to 1090 MHz.

4. The airborne radar system as set forth in claim 2, wherein said phase shift is inserted bit by bit at a 180°

phase shift per bit change.

5. The airborne radar system as set forth in claim 1, including two antenna arrays.

6. The airborne radar system as set forth in claim 5, wherein one of said arrays is a top circular array antenna and said other array is a bottom circular array antenna.

7. The airborne radar system as set forth in claim 1, wherein said radio-frequency electronics include a switch that switches between a power amplifier and a low-noise amplifier.

8. The airborne radar system as set forth in claim 7, wherein said switch switches to said power amplifier when said radar transceiver is transmitting a signal through said antenna arrays and switches to said low-noise amplifier when the antenna arrays receive a signal.

9. The airborne radar system as set forth in claim 8, wherein said radio-frequency electronics include a demodulator to demodulate or down convert signals received by said antennas.

10. The airborne radar system as set forth in claim 9, wherein said radar transceiver includes a digital signal processor.

11. The airborne radar system as set forth in claim 10, wherein said digital signal processor performs matched filtering on a received signal to estimate target range.

12. The airborne radar system as set forth in claim 11, wherein said digital signal processor also includes a program to estimate an angle-of-arrival for each signal received over a field-of-view.

13. The airborne radar system as set forth in claim 12, wherein said angle-of-arrival estimate includes both azimuth and elevation information.

14. The airborne radar system as set forth in claim 13, further including digital filtering to enhance a signal-to-noise ratio.

15. The airborne radar system as set forth in claim 14, wherein target angles-of-arrival are indicated by peaks in a multiple signal classification spatial spectrum that is calculated along with scanning of a steering vector over the required field-of-view.

16. The airborne radar system as set forth in claim 15, wherein peaks are extracted from the multiple signal classification spatial spectrum, and the angles-of-arrival are based on the location of the peaks.

17. A method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system, the method comprising the steps of:

providing a standard ADS-B transmitter and encoder, a phase modulator including a digital synthesizer, radio-frequency electronics, antennas, and a radar transceiver,

synthesizing digital-based band signals from said ADS-B transmitter with additional random phase modulation using said digital synthesizer;

using said antennas to both transmit and receive signals; and

estimating angles-of-arrival for each target in a field-of-view.

18. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 17, including the step of demodulating the signals received by said antennas.

19. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 17, including the steps of providing a digital signal processor and performing matched filtering on received signals.

20. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 19, including the step of estimating a target range of identified targets using said digital signal processor.

21. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 17, wherein said radio-frequency electronics perform the steps of up and down conversion, amplification and filtering at 1090 MHz center frequency for each antenna.

22. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 17, wherein said antennas include a top 16-element circular array and a bottom 16-element circular array.

23. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 17, wherein said radar transceiver controls phase modulation of a waveform generated by said ADS-B transmitter.

24. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 23, wherein said radar transceiver provides real-time target detection tracking.

25. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 17, including the step of providing a standard ADS-B receiver to receive and decode standard ADS-B messages.

26. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 17, wherein said digital synthesizer adds a phase shift to an analog waveform containing both I and Q channels, the waveform being generated by the ADS-B transmitter.

27. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 26, wherein said digital synthesizer converts said analog waveform to 1090 MHz.

28. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 17, including the steps of providing a switch, a power amplifier, and a low-noise amplifier in said radio-frequency electronics;

switching to the power amplifier when at least one of said antennas is used to transmit a signal; and

switching to said low-noise amplifier when at least one of said antenna elements is used to receive a signal.

29. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 17, including the steps of providing an I/Q demodulator in said radio-frequency electronics and demodulating or down-converting a radio-frequency signal.

30. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 17, wherein the angles-of-arrival for each target include azimuth and elevation.

31. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 17, including the steps of calculating a multiple signal classification spatial spectrum and scanning a steering vector over the field-of-view.

32. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 30, including the steps of extracting peaks from the multiple signal classification spatial spectrum, and computing angles-of-arrival based upon the location of the peaks.

33. A method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system, the method comprising the steps of:

providing a standard ADS-B transmitter and encoder, a phase modulator, radio-frequency electronics including a digital signal processor, antennas, and a radar transceiver,

synthesizing digital-based band signals from said ADS-B transmitter with additional random phase modulation;

demodulating signals received by said antennas; and

estimating target range using said digital signal processor.

34. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 33, wherein said antennas both transmit and receive signals.

35. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 33, including the step of performing matched filtering on a received signal.

36. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 33, including the step of estimating angles-of-arrival for each target in the field-of-view.

37. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 36, wherein the angles-of-arrival include both azimuth and elevation.

38. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 33, including the step of calculating a multiple signal classification spatial spectrum of data sets derived from signals received from said antennas.

39. The method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system as set forth in claim 38, including the steps of extracting peaks from the multiple signal classification spatial spectrum and computing angles-of-arrival based on the location of the peaks.