DIRECTION FINDING - A SIGNAL SUBSPACE APPROACH

The classical direction finding problem is concerned with the task of detecting and estimating the directions from which multiple energy wavefronts impinge on an array of sensors. It is desired to use the wavefront induced sensor signals to estimate the directions of wavefront travel as well as other wavefront related characteristics. This problem is formulated in the signal subspace that in turn leads to a number of benefits chief among which is the ability to resolve closely spaced coherent sources. In order to realize this potential, however, a parametric optimization problem need be solved. An effective nonlinear programming algorithm is developed for this purpose along with a parameter initialization procedure. Numerical examples are presented to demonstrate the superrsolution capability of the signal subspace algorithm.