Systems and methods for discriminating signals in a multi-band detector

• US 7,450,051 B1
• Filed: 11/18/2005
• Issued: 11/11/2008
• Est. Priority Date: 11/18/2005
• Status: Active Grant

• Current Assignee: Valentine Research, Inc.
• Original Assignee: Valentine Research, Inc.
• Inventors: Valentine, Michael D., Carrelli, Gary E.
• Primary Examiner(s): Tarcza; Thomas H.
• Assistant Examiner(s): LIU, HARRY K
• Application Number:
  US11/283,095
• Time in Patent Office: 1,089 Days
• Field of Search: 342/2, 342/20, 342/115, 342/159, 342/193, 725/15
• US Class Current: 342/2
• CPC Class Codes: G01S 7/022 Road traffic radar detectors
• CPC Class Codes: H03D 7/1408 with diodes

Abstract

A radar detector is operated to suppress nuisance radar alerts by identifying a first signal in radar band of interest, e.g., having a frequency that is a harmonic of a first nuisance local oscillator frequency leaked from a nearby radar detector and identifying a second signal having a frequency that is a harmonic of a second nuisance local oscillator frequency leaked from the radar detector where the first and second local oscillators are companion signals. A detector is also provided that suppresses nuisance radar alerts by detecting a first signal in a radar band, providing a first alert designating the detection of the first signal, determining that the first signal is a nuisance signal, providing a second alert designating that the first signal is a false alarm, and turning off the second alert after a predetermined period.

Claims

1. A method of operating a radar detector to suppress nuisance radar alerts due to signals received in a radar band which are not radar signals of interest, said method comprising:

scanning at least a radar band of interest;

detecting a first signal in said radar band of interest;

deciding whether said first signal is a nuisance signal that should be suppressed by determining if a second signal is detected that is a companion of said first signal, said first and second signals being companion signals if a pattern associates said first signal as being derived from a first nuisance local oscillator frequency leaked from another radar detector while said other radar detector is sweeping a first frequency range and said pattern associates said second signal as being derived from a second nuisance local oscillator frequency leaked from said other radar detector while said other radar detector is sweeping a second frequency range different from said first frequency range, wherein said frequency of said second signal is different from and not harmonically related to said frequency of said first signal; and

suppressing an alert for said first signal if said first signal is determined to be a nuisance signal.

2. The method according to claim 1, wherein said first and second signals are judged to be companion signals if said pattern comprises detecting said first and second signals as being alternatively switched on and off.

3. The method according to claim 1, wherein said first signal is detected in the Ka band and said second signal is detected outside of said Ka band.

4. The method according to claim 1, wherein:

said first signal is in the range of 33.4 to 34 gigahertz; and

said second signal is outside of said Ka band in the range of 32 to 33 gigahertz.

5. The method according to claim 1, wherein said first and second signals are not both always simultaneously on.

6. The method according to claim 1, wherein said first and second signals are detected such that said first signal is suppressed before said alert is issued.

7. The method according to claim 1, wherein said first signal is detected before said second signal is detected such that said alarm is initially issued, said method further comprising:

after detecting said second signal, identifying said alarm issued for said first signal as being a false signal if said first signal is determined to be a nuisance signal;

removing said alarm issued for said first signal; and

after a predetermined period of time, ceasing to identify said alarm for said first signal as being false.

8. A radar detector comprising:

a first processing stage having an antenna for receiving electromagnetic signals and a first mixer for mixing said electromagnetic signals received by said antenna with a first local oscillator signal to generate a first intermediate frequency signal;

a second processing stage coupled to said first processing stage, said second processing stage having a second mixer for mixing said first intermediate frequency signal with a second local oscillator signal to generate a second intermediate frequency signal within a second intermediate frequency range;

detector circuitry coupled to said second processing stage for detecting received electromagnetic signals within at least the X, K and Ka radar bands that have been shifted in frequency to said second intermediate frequency range; and

signal conditioning and control circuitry for controlling said first and second processing stages and for discriminating false alarm signals, wherein said signal conditioning and control circuitry;

detects for a first signal in a radar band of interest;

decides whether said first signal is a nuisance signal that should be suppressed by determining if a second signal is detected that is a companion of said first signal, said first and second signals being companion signals if a pattern associates said first signal as being derived from a first nuisance local oscillator frequency leaked from another radar detector while said other radar detector is sweeping a first frequency range and said pattern associates said second signal as being derived from a second nuisance local oscillator frequency leaked from said other radar detector while said other radar detector is sweeping a second frequency range different from said first frequency range, wherein said frequency of said second signal is different from and not harmonically related to said frequency of said first signal; and

suppresses an alert for said first signal if said first signal is determined to be a nuisance signal.

9. The detector according to claim 8 wherein:

said first local oscillator signal comprises a swept signal from a voltage controlled oscillator that is controlled by said signal conditioning and control circuitry,

said first signal is detected in said Ka band by sweeping at least a portion of said Ka band; and

said second signal is detected by sweeping below said Ka band.

10. The detector according to claim 9, wherein:

said first signal is in the range of 33.4 to 34 gigahertz; and

said second signal is outside of said Ka band in the range of 32 to 33 gigahertz.

11. The detector according to claim 8, wherein said first and second signals are judged by said signal conditioning and control circuitry to be companion signals if said signal conditioning and control circuitry determines that said first and second signals are switched on and off in a pattern such that said first and second signals are not both always simultaneously on.

12. The detector according to claim 8, further comprising:

an alarm coupled to said signal conditioning and control circuitry wherein said alarm is turned on by said signal conditioning and control circuitry if said first signal is detected without also detecting said second signal.

13. The detector according to claim 12, wherein:

said alarm comprises an audible alarm and a visual alarm.

14. The detector according to claim 8, further comprising:

an alarm coupled to said signal conditioning and control circuitry wherein said alarm is not turned on by said signal conditioning and control circuitry if both said first and second signals are detected and said first signal is determined to be a nuisance signal.

15. The detector according to claim 8, further comprising a display coupled to said signal conditioning and control circuitry, wherein:

said display provides a first alert to designate that a signal is detected in a radar band of interest; and

said display provides a second alert to designate that a previously detected signal is a false alarm.

16. A computer readable medium having stored thereon, software code for discriminating between electromagnetic signals received by a radar detector comprising:

code configured to identify a first signal of interest in a predetermined radar band;

code configured to identify whether a second signal is detected

code configured to decide whether said first signal is a nuisance signal that should be suppressed by determining if a second signal is detected that is a companion of said first signal, said first and second signals being companion signals if a pattern associates said first signal as being derived from a first nuisance local oscillator frequency leaked from another radar detector while said other radar detector is sweeping a first frequency range and said pattern associates said second signal as being derived from a second nuisance local oscillator frequency leaked from said other radar detector while said other radar detector is sweeping a second frequency range different from said first frequency range, wherein said frequency of said second signal is different from and not harmonically related to said frequency of said first signal; and

code configured to suppress an alert for the detection of said first signal if said first signal is determined to be a nuisance signal.

17. The computer readable medium according to claim 16, further comprising software code thereon programmed to activate an alarm corresponding to said first signal if said first signal is detected and said second signal is not detected.

18. The computer readable medium according to claim 17, further comprising software code thereon programmed to track said first signal after said first signal has been detected by:

identifying whether said second signal becomes detected;

maintaining said alarm corresponding to said first signal if said second signal is not detected; and

activating a false alarm and turning off said alarm corresponding to said first signal if said second signal is subsequently detected and if said first signal is determined to be a nuisance signal.

19. The computer readable medium according to claim 16, further comprising software code thereon programmed to track said first signal as a suppressed signal if both said first and second signals are detected and said first signal is determined to be a nuisance signal.

20. The computer readable medium according to claim 16, further comprising software code programmed to cause said detector to sweep at least said X, K and Ka bands before determining whether said first and second signals were located.

21. The computer readable medium according to claim 16, further comprising software code programmed to track detected signals over multiple sweeps and to identify said first signal as suppressed if said first and second signals are detected, regardless of the order in which said first and second signals are detected if said first signal is determined to be a nuisance signal.

22. The computer readable medium according to claim 16, further comprising software code programmed to cause:

a first alert if said first signal is detected and said second signal is not detected; and

a second alert for a predetermined time if said second signal is detected subsequent to activating said first alert to indicate the detection of a false alarm, whereby after said predetermined period, both said first and second alerts are turned off.