Vehicular Traffic Surveillance Doppler Radar System

• US 20110095938A1
• Filed: 01/04/2011
• Published: 04/28/2011
• 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.
• Granted Patent: US 8,138,966 B2
• Time in Patent Office: Days
• 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 comprising:

an antenna circuit portion configured to receive reflected modulated FM signals from a target;

a ranging circuit portion configured to perform a quadrature demodulation on the reflected modulated FM signals; and

the ranging circuit portion configured to determine, for the target, a range measurement based upon phase angle measurements derived therefrom.

2. The vehicular traffic surveillance Doppler radar as recited in claim 1, wherein the ranging circuit portion comprises direction-sensing capabilities to determine a heading of the target with respect to the Doppler radar system.

3. A vehicular traffic surveillance Doppler radar for use in a multiple vehicle environment including a plurality of target vehicles, the vehicle traffic surveillance Doppler radar comprising:

a direction-sensing Doppler radar associated with a source vehicle;

the Doppler radar configured to perform a quadrature demodulation on reflected modulated FM signals received from at least a portion of a plurality of target vehicles;

the Doppler radar configured to determine a range measurement for the at least a portion of the plurality of target vehicles based upon phase angle measurements derived therefrom.

4. The system as recited in claim 3, wherein the source vehicle comprises a law enforcement vehicle.

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

6. The system as recited in claim 3, 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 thereform as reflected modulated FM signals.

7. The system as recited in claim 6, 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.

8. The system as recited in claim 6, 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.

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

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

receiving second reflected modulated FM signals at the Doppler radar from a 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.

10. The method as recited in claim 9, 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.

11. The method as recited in claim 9, further comprising determining which of the first and second targets is closer based on the respective ranges of the first and second targets.

12. The method as recited in claim 9, 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.

13. The method as recited in claim 9, 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.