Heterodyned double sideband diplex radar

Abstract

A heterodyned double side band diplex radar system determines the range of targets as a function of the amplitude variation of reflected target Doppler signals. The present invention includes a real radar system that accurately determines the range of fading targets and the magnitude of the velocity of the targets. The present invention also includes a complex radar system that determines the relative velocity of targets in addition to the range of targets. In either embodiment, the transmitted signal may be modulated with a pseudo-random number (“PN”) sequence to attenuate or decorrelate signals reflected from targets beyond some maximum range. The modulation of the pseudo-random sequence may also attenuate or decorrelate signals reflected from targets closer than some minimum range. The present invention also includes a real radar system having BPSK modulation with PN coding. The selection of BPSK modulation enables or facilitates the implementation of a portion of the system in digital form. In particular, the generation of the IF signals needed to modulate and demodulate the transmitted and received signal may be implemented in a programmable logic device (“PLD”).