Trigonometric high-resolution method to resolve two close targets

Three-subaperture methods for estimating the elevation angles of two targets within the 3 dB beamwidth for the main aperture of a linear array are discussed and applied to the case of a radar target in the presence of multipath over a smooth surface. Simulation results and comparison with the three-subaperture maximum-likelihood estimator by Cantrell et al. are presented. A four-subaperture technique to solve the in-phase and antiphase signal cases is suggested.