Method of reducing angle noise in a radar

Abstract

A method of reducing angle noise in return signals to a monopulse radar having a radome is shown to consist of the steps of: (a) transmitting a pair of signals at frequencies equally spaced above and below the tuning frequency of the radome; (b) digitally processing the return signals to form the complex monopulse ratios of the return signals corresponding to each one of the transmitted signals; (c) determining, by comparing the magnitudes of each monopulse sum and monopulse difference signals with the level of respective predetermined sum and difference reference signals, whether or not angle noise is exhibited and whether or not the signs of the imaginary parts of the monopulse difference signals differ; (d) comparing, to a threshold level, the amplitudes of the monopulse difference signals of those return signals which exhibit angle noise to select return signals exceeding such threshold level and whose signs differ; and, (e) averaging the real parts of the complex monopulse ratios of the return signals which exceed the threshold level finally to produce tracking signals in the presence of angle noise.