An Adaptive Nulling System for a Narrow-Band Signal with a Look-Direction Constraint Utilizing the Conjugate Gradient Method

The problem consists of adaptively adjusting the weights of an antenna array to eliminate unwanted interference sources (jammers) with an arbitrary look-direction constraint. The technique uses the adaptive conjugate gradient method instead of the popularly used method of steepest descent to eliminate the jammer components, thus minimizing the error between the received signal and the actual one. This iterative method minimizes the L2 norm, or the mean square error, and is guaranteed to converge in a finite number of steps which is not available for the present techniques utilized to solve this problem. Improvement in rate of convergence is thus achieved at the expense of algorithmic complexity.