Image inclination in differential synthetic aperture ladar

A phenomenon, referred to as differential synthetic aperture ladar (DSAL) image inclination, is reported. The phenomenon states that in a stably operating DSAL system, the high-resolution image generated by DSAL technique is possibly inclined in the range direction. The range-inclined DSAL image does not change its resolution but makes the DSAL image differ from the real target structure, resulting in a kind of geometric deformation. Theoretical analysis shows that this inclination phenomenon originates from the geometric setting of the two receiving subapertures in the DSAL hardware and is independent of the target distance. By properly setting the subapertures, this phenomenon could be minimized. Detailed DSAL experimental results verified the theoretical interpretation. Methods to correct the inclined DSAL image are suggested. (C) 2019 Society of Photo-Optical Instrumentation Engineers (SPIE)