An adaptive nulling algorithm based on signal subspace concepts

A novel eigenvector-based adaptive nulling algorithm, intended for anti-jam uplink satellite communications applications, is presented. The algorithm exploits a priori knowledge of high-power user terminal locations, together with the signal covariance matrix, to determine a basis set for the estimated jammer space. The computed signal weight vector is orthogonal to the estimated jammer space and maximally coupled to the user space. The nulling system is configured to suppress jammers exceeding a preset power threshold. Low-power, ineffective jammers cannot saturate the nuller. Theater coverage for low-power, low-data-rate users operating below threshold is facilitated through synthetic auxilliary user signals which are added to the signal covariance matrix. Simulation results are presented involving a 19-beam multiple beam antenna