A channel phase error compensation method for multi-channel synthetic aperture ladar

With the development of earth remote sensing technology, it is required to obtain high resolution and wide swath simultaneously. Synthetic Aperture Ladar(SAL) can achieve high-resolution images, but swath of images is limited. The multi-channel SAL combined with digital beamforming(DBF) technology provides a good solution to solve the problem. However, phase error between channels will degrade the quality of DBF. SAL is sensitive to phase error because of short wavelength of laser, which is at least three orders of magnitude shorter than that of synthetic aperture radar (SAR). Therefore, the conventional compensation methods can not satisfy the requirement of high compensation accuracy. In this paper, a compensation method based on antenna pattern and Doppler correlation coefficient is proposed, constructing a cost function. By minimizing the combined cost function, the phase error between channels is estimated with a good accuracy better than 1 degrees. And simulation results validate the effectiveness of the proposed method.