Exploiting multipath from airborne platforms for direction of arrival estimation

In the direction-of-arrival estimation, the scattering of the incident signal from airborne platforms is often neglected or considered as a source of clutter. However, these additional signal paths, mostly due to the diffraction from the platform wedges, contain useful information about the incoming waves. Recent research showed that the waves reflected from the known objects surrounding the target improve the accuracy of the target estimation or image. We show that similar improvement is obtained if the array interaction with the hosting platform is taken into the account. We incorporate the multipath into the signal processing algorithms, and study the improvement by computing the Cramer-Rao bound. We show that the exploitation of the multipath from the sensor platforms improves the estimation accuracy significantly. Moreover, the capacity to resolve multiple incident signals is enhanced.