Wideband angle-of-arrival disambiguation for sparse arrays

It is well understood that when array antennas are separated by more than a half-wavelength that angle ambiguities occur. However, by exploiting wideband signal characteristics in the frequency domain, the angle ambiguity may be mitigated. Specifically, we observe that wideband beamforming causes signals from various angle ambiguities to slope differently when viewed in a frequency vs. angle space. These slope differences allow one to discriminate between the various angle ambiguities. Furthermore, we show that derivative based updating (DBU) inherently tracks these slopes and provides a spectral response to accurately measure the received signal slopes. With this, we conclude that angle ambiguities may be overcome for widely spaced uniform linear antenna arrays with wideband signaling allowing one to accurately identify and discriminate all arrival cone-angles.