Detection of targets by a pulse series

Abstract

Generally, a series of echo signals is the basis for target detection. An arbitrary length of this series is applicable by using the beam agility, which enables adaptation of the transmit energy to target strength and of the required Doppler resolution. The step scan operation of a phased array provides an important difference when compared with mechanical scanning radars with respect to the detection procedure and clutter suppression. Clutter suppression may be divided between strong fixed clutter and varying Doppler-shifted clutter, the first of which may be suppressed by a simple recursive filter. Using post processing the latter can be arranged advantageously, in an adaptive manner, after the filter bank. Sea clutter suppression can be improved by a special multiplex operation of the beam, resulting in elongated dwell times in each beam position. For a longer series of pulses, a possible Doppler shift during the dwell time has to be considered. The usual filter bank shows a degraded detection performance because the target energy is distributed into several filters. An autocorrelation estimation test will give a more robust performance in this case. The detection performance is evaluated and compared on the basis of simulation studies.