Traffic radar with target duration tracking

• US 7,705,772 B1
• Filed: 01/19/2009
• Issued: 04/27/2010
• Est. Priority Date: 01/19/2009
• Status: Active Grant

• Current Assignee: Kustom Signals Incorporated (MPD Incorporated)
• Original Assignee: Kustom Signals Incorporated (MPD Incorporated)
• Inventors: Shelton, Maurice E.
• Primary Examiner(s): Sotomayor; John B
• Application Number:
  US12/356,000
• Time in Patent Office: 463 Days
• Field of Search: 342/104, 342/108, 342/111, 342114-116, 342/176, 342/179, 342/189, 342/192, 342/196
• US Class Current: 342/104
• 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 7/354 Extracting wanted echo-signals Doppler systems G01S13/50
• CPC Class Codes: G01S 7/356 involving particularities of FFT processing

Abstract

A traffic radar utilizes digital signal processing (DSP) to determine targets based on signal strength histories. From these histories, a target vehicle having the strongest Doppler return signal is identified and its speed is displayed, and a target vehicle having the highest frequency return signal is identified and its speed is displayed. The traffic radar may also display the relative strength of the strongest return signal and the relative strength of the highest frequency return signal, thereby showing a comparison of the strengths of the return signals from the target vehicles.

Claims

1. In a traffic radar, a method of tracking and validating a target from Doppler return information comprising:

(a) receiving Doppler return information containing at least one return signal derived from a moving target, and presenting said information as digital data,

(b) transforming said data into the frequency domain to provide a spectrum that includes frequency components corresponding to Doppler return signals contained in said information,

(c) storing said frequency components in memory,

(d) identifying a peak magnitude of each component that exceeds a predetermined threshold to thereby identify current target peaks,

(e) comparing said current target peaks with previously found target peaks and accumulating their magnitudes to provide a target history for each of said components,

(f) from said target histories, identifying a target which has the strongest Doppler return signal, and determining the speed thereof,

(g) from said target histories, identifying a target that has the highest frequency return signal, and determining the speed thereof, and

(h) displaying either or both of the determined speeds.

2. The method as claimed in claim 1, further comprising the step of displaying the relative strength of the strongest return signal, and displaying the relative strength of the highest frequency return signal, thereby showing a comparison of the strengths of the return signals from the target vehicles.

3. In a traffic radar, a method of tracking and validating a target from Doppler return information comprising:

(a) receiving Doppler return information containing at least one return signal derived from a moving target, and presenting said information as digital data,

(b) transforming said data into the frequency domain to provide a spectrum that includes frequency components corresponding to Doppler return signals contained in said information,

(c) storing said frequency components in memory,

(d) conducting a moving average comparison of said components in memory to identify a peak magnitude of each component that exceeds a predetermined threshold to thereby identify current target peaks,

(e) comparing said current target peaks with previously found target peaks and accumulating their magnitudes to provide a target history for each of said components,

(f) from said target histories, identifying a target which has the strongest Doppler return signal, and calculating the speed thereof,

(g) from said target histories, identifying a target that has the highest frequency return signal, and calculating the speed thereof, and

(h) displaying either or both of the determined speeds.

4. The method as claimed in claim 3, further comprising the step of displaying the relative strength of the strongest return signal, and displaying the relative strength of the highest frequency return signal, thereby showing a comparison of the strengths of the return signals from the target vehicles.

5. A method of processing Doppler return information in a traffic radar comprising the steps of:

(a) receiving Doppler return information containing at least one return signal derived from a target vehicle, and presenting said information as digital data,

(b) transforming said digital data into the frequency domain to provide an input spectrum that includes frequency components corresponding to Doppler return signals contained in said information,

(c) storing said frequency components in a memory,

(d) determining a peak magnitude of each component in memory that exceeds a predetermined threshold to thereby identify current target peaks,

(e) comparing said current target peaks with previously found target peaks and accumulating their magnitudes to provide a target history for each of said components,

(f) from said target histories, identifying a target which has the strongest Doppler return signal, and calculating the speed thereof,

(g) from said target histories, identifying a target that has the highest frequency return signal, and calculating the speed thereof,

(h) displaying either or both of the calculated speeds, and

(i) displaying information relating to the signal strength of either or both of the displayed speeds.

6. The method as claimed in claim 5, wherein said step (i) includes displaying the relative strength of the strongest return signal, and displaying the relative strength of the highest frequency return signal, thereby showing a comparison of the strengths of the return signals from the target vehicles.

7. The method as claimed in claim 5, wherein said step (d) includes comparing the magnitude of frequency bins within said input spectrum to a weighted moving average thereof, identifying magnitudes greater than said weighted moving average as target peak bins, and comparing the magnitude of each of said bins to said weighted moving average to determine a signal-to-noise ratio therefor.

8. In a traffic radar, apparatus for processing and displaying Doppler return information comprising:

(a) means for receiving Doppler return information containing at least one return signal derived from a moving target, and for presenting said information as digital data,

(b) means for transforming said data into the frequency domain to provide a spectrum that includes frequency components corresponding to Doppler return signals contained in said information,

(c) means for storing said frequency components in memory,

(d) means for determining current target peak signals based on moving average comparisons,

(e) means for accumulating and storing history arrays of respective signal-to-noise ratios of said target peak signals,

(f) means for providing a list of qualified targets based on said history arrays,

(g) means for calculating the speed of the qualified target which has the strongest Doppler return signal,

(h) means for calculating the speed of the qualified target which has the highest frequency Doppler return signal,

(i) a first display responsive to said strongest qualified target for displaying information relating to the signal strength of the strongest target, and

(j) a second display responsive to said highest frequency qualified target for displaying information relating to the signal strength of the fastest target.

9. Apparatus as claimed in claim 8, further comprising a first target signal traffic bar graph associated with said first display for indicating the relative signal strength of said strongest target, and a second target signal traffic bar graph associated with said second display for indicating the relative strength of said fastest target, whereby the operator can visually correlate vehicle speed and return signal strength.