Matched filter for frequency-modulated continuous-wave radar systems

Abstract

A method of signal processing the output of a linearly frequency-modulated continuous-wave (f.m.c.w.) radar is described. The system performs a spectrum analysis, and it is based on a matched-filtering technique, similar to pulse compression, using a dispersive delay line and an extra associated frequency-swept oscillator. The main advantages over existing f.m.c.w. radar signal-processing techniques are (a) negligible loss in signal/noise ratio (b) the ability to trade output-signal bandwidth with maximum range (c) the fact that the detected signal output consists of serial time pulses, with the amplitudes and time delays representing the signal strength and range of each target, respectively. Time sidelobes are inherent in any f.m.c.w. radar and also in the signal processing proposed; a method is discussed for their reduction, and the effects of nonlinearities on the system performance are considered. The system is most suitable for use in high-resolution very short-range radar, such as that used for observing harbour docking and airfield surface movement.