Bearing estimation techniques for improved reception of spread spectrum signals

The novel use of bearing estimation techniques to determine the direction of arrival of direct sequence spread spectrum signals is described. Firstly, the basic ideas behind bearing estimation are discussed and it is shown how these may be best applied to a spread spectrum receiver array. Then, some simple algorithms are compared and it is shown that the multiple signal classification algorithm (MUSIC) provides good angular resolution for a fixed computational overhead. One major shortcoming of the MUSIC algorithm is that it fails in the presence of coherent spread spectrum multipath returns. Spatial smoothing algorithms are shown to be a solution to this problem and the behaviour of such techniques is discussed