PERFORMANCE ANALYSIS OF DERIVATIVE CONSTRAINT ADAPTIVE ARRAYS WITH POINTING ERRORS

The performance of adaptive arrays with arbitrary order derivative constraints to avoid the signal nulling caused by the error in the steering angle is investigated. The generalized sidelobe canceller (GSC) is used to evaluate the bearing responses of adaptive arrays with pointing errors. Under the assumption of equispaced linear arrays, we utilize the Legendre polynomial to derive a closed-form formula for the sidelobe leakage factor, the ratio in which the signal leaks into the GSC sidelobe cancelling branch. Moreover, we derive the effective beamwidth, the maximum range of pointing inaccuracy allowable to keep the signal loss in array output less than a given value, for the GSC with the delay-and-sum quiescent beamformer. Such kind of adaptive arrays can achieve the maximum output signal-to-noise ratio when the presteering is perfect, and its performance is independent of the location of the phase origin. Numerical results are presented to confirm the analysis.