Air Force Research Laboratory
Target altitude estimation is an important problem in Over-The-Horizon Radar (OTHR) systems for target tracking and classification. Narrow signal bandwidth and rich propagation environment in OTHR render this problem difficult and challenging. In this paper, the authors develop a novel technique that allows accurate altitude estimation for a maneuvering target during its ascending or descending flight. The proposed technique considers a Multiple-Input Multiple-Output (MIMO) OTHR platform and utilizes the difference in the Doppler signatures generated in a micro-multipath propagation environment. The separability of the multi-component Doppler signatures in the time-frequency domain is used to individually estimate the elevation angles of these paths, which are otherwise infeasible to obtain, due to their small angular separation.