Monopulse Imaging Technology Based on Super-resolution in Doppler Domain

Monopulse angle measuring technology combined with scanning radar can effectively solve the problem of blind area in forward-looking radar imaging. However, it fails to work when multiple targets exist in the same beamwidth, resulting in the degradation of imaging quality. Aiming at this problem, monopulse imaging technology based on super-resolution in Doppler domain is proposed in this paper, which utilizes Doppler gradient differences caused by relative movement between targets and radar platform to separate targets in different azimuth. Conventional fast Fourier transform (FFT) method is adopted to convert the signal into the Doppler domain, but it suffers from low resolution and high sidelobes. Thus, an iterative adaptive estimation method based on minimum mean square error (MMSE) is proposed to suppress sidelobes in Doppler domain, achieving the preliminary separation. Then, monopulse angle measuring technology based on sum to difference ratio in Doppler domain is applied to complete the energy projection, achieving secondary separation. The simulation results verify the effectiveness of the proposed algorithm in improving azimuth resolution.