FREQUENCY DOMAIN, PULSE COMPRESSION RADAR APPARATUS FOR ELIMINATING CLUTTER

摘要

A CW radar apparatus (continuous wave) to pulse compression, frequency domain comprises a frequency synthesizer providing CW signals at a radio frequency, FRF, and an intermediate frequency, fIF; a linear frequency modulation (LFM) producing a LFM ramp sawtooth wave having a variable ramp frequency, FLFM, and a mixer for combining the FLFM signal with the FRF signal so as to produce a CW radar signal having a frequency (FRF + FLFM). A transmitter transmits the CW radar signal (FRF + FLFM) and a receiver receives the delayed CW radar return signals reflected by the fixed echoes in an echo scope and reflected from a target at a target range. A second mixer is included to perform a decremental conversion timed target return signals and clutter in a processing intermediate frequency and a third mixer is provided for extracting the signal of the delayed signals FLFM target return echo and fixed intermediate frequency to obtain a frequency domain-time, analog signals of target and clutter rectangular wave. A timing gate and a frequency notch filter is connected to receive the target rectangular wave signals and clutter, the notch filter having at least one frequency notch for filtering the fixed echo signal square wave while allowing the target signal to rectangular wave when, as is usually the case, the frequency characteristics and fixed target echo signals are different. A sync detector provides phase components (I) and quadrature (Q) of the target signal and an A / D converter and sampler digitized and sampled signal components I and Q samples being processed in a compressor FFT digital pulses then in a Doppler processor FFT to obtain information doppler cells and scope.