Traffic radar with digital signal processing

摘要

A traffic radar processes Doppler return information by analysis of the received frequency spectrum in order to improve target identification and minimize interference and unwanted harmonics. Digital signal processing including transformation of the return information into the frequency domain is employed to provide multiple modes of operation including a stationary mode where either the strongest or the fastest Doppler return signal may be selectively recognized, and moving modes for monitoring traffic moving in both the opposite direction and the same direction as the patrol vehicle. In the moving modes either strongest or fastest signal processing may be elected, and operation when the patrol and target vehicles are moving in the same direction is provided irrespective of whether the patrol vehicle is moving faster or slower than the target vehicle. The speed of the patrol car is determined by recognizing a signature that exhibits an asymmetry due to the cosine effect. Interference and harmonics are detected and suppressed by recognizing unwanted harmonic patterns and eliminating signal magnitudes at the harmonic frequencies. The radar has multi-band capability and recognizes the frequency band of a selected antenna to automatically configure the radar for correct processing of Doppler return information.