Robust Perturbation Algorithms for Adaptive Antenna Arrays

Algorithms for adjusting the weights of an adaptive array usually employ some form of gradient estimation. In cases where a coherent receiver is not possible, or is uneconomical, a single port receiver using weight perturbations can be used to obtain the gradient estimate. The perturbations of the weights about some nominal value introduces noise into the receiver which can prevent simultaneous signal reception and weight adaption. A perturbation sequence is introduced that permits simultaneous adaption and reception by use of weight perturbations that do not obstruct the look direction constraint. It is also shown that this sequence is generally shorter in length than previously described sequences, and offers scope for computational savings through reduction of the number of projection operations required.