Theoretical and experimental investigation on signal processing in an adaptive spatial filter

The possibilities and limitations of the so-called side-lobe canceller were demonstrated. The mathematical description of the control loops leads to various circuits from which the bandpass correlator loop is suggested because of its low drift and relatively simple realization. The interference suppression, defined as the ratio of interference power in the main channel to the total interference output power, is evaluated as a function of signal bandwidth, array antenna dimensions and decorrelation of the signals caused by different transfer functions in the receiver front end. The influence of the short-term correlation on the error and the influence of the real components on interference suppression and control loop stability were assessed. Additional simulation results and some experimental work show that, in the case of radar, it is possible to achieve 20 db of interference suppression with careful design of the control loops.