WIDEBAND ACTIVE SIGNAL PROCESSOR PERFORMANCE IN THE PRESENCE OF MULTIPATH
JF DIX, D HASSALL · 2024
The wide bandsignal processor is recognised for its good range resolution, which is useful for extracting target detail and lowering the reverberation level.Such a processor can be realised simply by utilising a short pulse transmission and detecting the envelope or by using a cross correlator, where the range resolution is determined by the reciprocal of the bandwidth of the signal transmitted.The advantage ofthe cross correlator is that the pulse length of the signal transmitted can be chosen quite independently to achieve the required detection performance against a noise background.A further advantage, not so widely appreciated, is the ability to reduce echo fading, arising from multipath, by an equivalent diversity receiver action inherent in the correlator itself.Practical measurements on a calibrated point target have demonstrated this improved echo stability which confers an improved probability of target detection.What was also discovered was an enhancement in reverberation level over that achieved by a simple short pulse receiver with identical range resolution which, in turn, means improved false alarm statistics.To improve the understanding of the correlator in this extra role, computer modelling was undertaken to see how well results could be matched to practice.Modelling results have shown good agreement with practice, enabling a much better appreciation of the correlator operation in terms of signal parameters and relevant environmental properties.1 .