Direction Finding Using ESPRIT with Interpolated Arrays

The technique of interpolated arrays is applied to ESPRIT-type direction finding methods. The resulting method uses sensor arrays with an arbitrary configuration, thus eliminating the basic restrictive requirement of ESPRIT for two (or more) identical arrays. Our approach allows for resolving D narrowband signals if the number of sensors is, at least, D + 1, while the original ESPRIT method requires at least 2D sensors. Moreover, it is shown that while ESPRIT performs poorly for signals propagating in parallel that the application of interpolation, in this case, can significantly improve the original ESPRIT performance. Our approach relies on the full knowledge of the array manifold like most basic array processing techniques and in contrast with the original ESPRIT. Therefore, the advocated technique should not be considered as a competitor of ESPRIT but as an exploitation of the ESPRIT ideas for standard direction finding.