Multi-subaperture Trajectory Estimation for Stripmap UAV SAR

The estimation of two-dimensional motion parameters is the premise of high-precision synthetic aperture radar (SAR) error compensation. In strip mode, it is difficult to directly estimate all phase errors in one range block, so it isn't accurate to estimate the trajectory using the whole range block. In this paper, a two-dimensional displacement estimation process for multi-rotor multi-rotor unmanned aerial vehicle (UAV) SAR is proposed. It divides the whole aperture into several subapertures, then select several range blocks in each subaperture and calculates their phase error gradients, next restores the two-dimensional displacement one subaperture by one subaperture. Considering that the velocity error will cause envelope error, it uses multiple iterations to decrease the influence of velocity error. Finally, the feasibility is verified by simulation.