AN EARTH-BASED RADAR HIGH RESOLUTION IMAGING TECHNOLOGY OF THE MOON BASED ON SUB-APERTURE DELAY DOPPLER ALGORITHM

The delay Doppler algorithm is the earliest developed and the most used frequency-domain imaging algorithm for the moon, which is suitable for low resolution imaging. Howeaver, this algorithm usually assumes that the Doppler phase induced by the rotation of the target is only first order. This assumption is not suitable for high resolution imaging with long-term observation. In this paper, an earth-based radar high resolution imaging technology based on sub-aperture delay Doppler algorithm is proposed. This paper first analyses the basic constraints of the sub-aperture division, which avoid the ARU and ADU effects in each sub-aperture and ensure that the Doppler phase is linear. Then, the sub-aperture delay Doppler imaging is performed to obtain the sub-aperture images. Then, multiple sub-aperture delay Doppler images can be projected into the geographic coordinate system based on the RD positioning model. Finally, multiple sub-aperture images can be coherently fused to obtain a full-aperture image. Computer simulation results and experimental results based on a distributed coherent radar prototype system validate the proposed algorithm.