The invention discloses an SAL (synthetic aperture ladar) full-aperture imaging method based on MEA (
minimum entropy autofocus) and deramp. With the method adopted, the problem of large movement errorbrought to echoes by the vibration of a carrying aircraft is solved. The method includes the following steps that: echo data signals are collected; range-direction
pulse compression is performed on the received data;
azimuth-direction deramp operation is performed on the range-direction pulse compressed data, so that the
azimuth-direction focusing phase of the range-direction pulse compressed data can be compensated; a data block is divided into sub-apertures,
phase error estimation is performed on sub-aperture data; sub-aperture phase errors are spliced, so that a full-aperture
phase error is obtained;
azimuth-direction
phase error compensation is performed on the whole range-direction pulse compressed data; azimuth-direction derramp is carried out, the azimuth-direction
pulse compression of the whole data of an SAL is achieved, the full-aperture imaging of the SAL is completed, and a high-resolution image is obtained. According to the method, sub-aperture division is performed on the data through a full-aperture imaging method; sub-aperture error phases are extracted through the MEA, all the error phases are spliced; overall
phase compensation is performed on full-aperture data;and therefore, the
utilization rate of
original data is improved, estimated errors are more accurate, compensation is more effective, and the resolution of the imaging of the synthetic aperture laserradar is effectively improved. When the method is used for compensating high-order phase errors in the imaging of the synthetic aperture
laser radar, a higher
signal-to-
noise ratio can be obtained, and the
image resolution and
image quality of the SAL can be improved.