Vehicular traffic surveillance doppler radar system

• US 7,864,102 B2
• Filed: 06/04/2007
• Issued: 01/04/2011
• Est. Priority Date: 02/16/2005
• Status: Active Grant

• Current Assignee: Applied Concepts Incorporated (Emerson Electric Company)
• Original Assignee: Applied Concepts Incorporated (Emerson Electric Company)
• Inventors: Aker, John L.
• Primary Examiner(s): PIHULIC, DANIEL T
• Application Number:
  US11/757,872
• Publication Number:
  US 20100013699A1
• Time in Patent Office: 1,310 Days
• Field of Search: 342/107, 342/114, 342/196, 342/104, 342/115
• US Class Current: 342/107
• CPC Class Codes: G01S 13/583 using transmission of continuous unmodulated waves, amplitude-, frequency-, or phase-modulated waves and based upon the Doppler effect resulting from movement of targets
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/92 for velocity measurement

Abstract

A vehicular traffic surveillance Doppler radar system and method for use of the same are disclosed. In one embodiment, the system comprises a modulation circuit portion for generating modulated FM signals. An antenna circuit portion transmits the modulated FM signals to a target and receives the reflected modulated FM signals therefrom. A ranging circuit portion performs a quadrature demodulation on the reflected modulated FM signals and determines a range measurement based upon phase angle measurements derived therefrom.

Claims

1. A vehicular traffic surveillance Doppler radar system, the system comprising:

a source vehicle;

a multiple vehicle environment comprising a plurality of target vehicles, each of the plurality of target vehicles having a range; and

a direction-sensing Doppler radar associated with the source vehicle, the Doppler radar for performing a quadrature demodulation on reflected modulated FM signals received from at least a portion of the plurality of target vehicles and determining a range measurement for the at least a portion of the plurality of target vehicles based upon phase angle measurements derived therefrom.

2. The system as recited in claim 1, wherein the source vehicle comprises a law enforcement vehicle.

3. The system as recited in claim 1, wherein the direction-sensing Doppler radar is operable to determine which of the plurality of target vehicles are approaching and which are receding with respect to the source vehicle.

4. The system as recited in claim 1, wherein the source vehicle generates modulated FM signals which are transmitted to the at least a portion of the plurality of the target vehicles and reflected therefrom as reflected modulated FM signals.

5. The system as recited in claim 4, wherein each of the ranges of the at least a portion of the plurality of target vehicles is determined based upon phase angle measurements associated with the reflected modulated FM signals.

6. The system as recited in claim 4, wherein a speed of each of the at least a portion of the plurality of target vehicles is determined based upon frequency signal differentials associated with the modulated FM signals and reflected modulated FM signals.

7. A vehicular traffic surveillance Doppler radar system, the system comprising:

a source vehicle;

a multiple vehicle environment comprising a plurality of target vehicles, each of the plurality of target vehicles having a range with respect to the source vehicle, speed, and radar cross-section; and

a direction-sensing Doppler radar associated with the source vehicle, the Doppler radar for performing Fourier transforms on reflected modulated FM signals received at the source vehicle and determining respective ranges and speeds of each of the plurality of target vehicles independently of the respective radar cross-sections of the plurality of vehicles.

8. The system as recited in claim 7, wherein the source vehicle comprises a law enforcement vehicle.

9. The system as recited in claim 7, wherein the direction-sensing Doppler radar is operable to determine which of the plurality of target vehicles are approaching and which are receding with respect to the source vehicle.

10. The system as recited in claim 7, wherein the source vehicle generates modulated FM signals which are transmitted to the plurality of target vehicles and reflected therefrom as reflected modulated FM signals.

11. A method for operating a vehicular traffic surveillance Doppler radar, the method comprising:

transmitting modulated FM signals from a Doppler radar to first and second targets;

receiving first reflected modulated FM signals at the Doppler radar from the first target;

receiving second reflected modulated FM signals at the Doppler radar from the second target;

transforming the received first and second reflected modulated FM signals to target spectrum;

analyzing frequency signal differentials associated with the target spectrum to determine respective speeds of the first and second targets; and

analyzing phase angle signal differentials associated with the target spectrum to determine respective ranges of the first and second targets.

12. The method as recited in claim 11, further comprising determining which of the first and second targets has a faster speed based on the respective speeds of the first and second targets.

13. The method as recited in claim 11, further comprising determining which of the first and second targets is closer based on the respective ranges of the first and second targets.

14. The method as recited in claim 11, further comprising determining the respective ranges of the first and second target vehicles independently of respective radar cross-sections of the first and second target vehicles.

15. The method as recited in claim 11, further comprising avoiding look-past error by calculating the respective ranges of the first and second target vehicles based upon the phase angle signal differentials.

16. A system for operating a vehicular traffic surveillance Doppler radar, the system comprising:

means for transmitting modulated FM signals from a Doppler radar to first and second targets;

means for receiving first reflected modulated FM signals at the Doppler radar from the first target;

means for receiving second reflected modulated FM signals at the Doppler radar from the second target;

means for transforming the received first and second reflected modulated FM signals to target spectrum;

means for analyzing frequency signal differentials associated with the target spectrum to determine respective speeds of the first and second targets; and

means for analyzing phase angle signal differentials associated with the target spectrum to determine respective ranges of the first and second targets.

17. The system as recited in claim 16, further comprising means for determining which of the first and second targets has a faster speed based on the respective speeds of the first and second targets.

18. The system as recited in claim 16, further comprising means for determining which of the first and second targets is closer based on the respective ranges of the first and second targets.

19. The system as recited in claim 16, further comprising means for determining the respective ranges of the first and second target vehicles independently of respective radar cross-sections of the first and second target vehicles.

20. The system as recited in claim 16, further comprising means for avoiding look-past error by calculating the respective ranges of the first and second target vehicles based upon the phase angle signal differentials.