فهرست مطالب سید محمد ذبیحی مداح

In this paper, the received signal equation of moving target with constant acceleration in a special case of BSAR, named one-stationary,in slant range plane is derived. In one-stationary geometry, usually range curvature and Doppler ambiguity is very large due to wide beam-width and assumption of accelerating movement of target. Hence, transforms such as Radon and Keystone have little accuracy for both estimating Doppler centroid and removing range cell migration. In this paper two-step algorithm is proposed for exact estimation of Doppler centroid. That is a combination of radon transform and a search algorithm.Then, by extraction of a system of equations, an accurate estimation of target’s velocity and acceleration is obtained and finally, an image formation algorithm is presented. Compared to usual algorithms, the accuracy of the derived equations and the strength of the proposed algorithm in the the presence of noise and clutter is confirmed by simulations.

In this paper, by considering a squint angle for synthetic aperture radar in the strip-map mode, a method is proposed for estimating parameters of a fixed acceleration moving target. Non-zero Doppler centroid and range-azimuth coupling in the squint mode add complexity to estimation equations of moving target parameters and cause Doppler ambiguity. This, in turn, causes to lose the efficiency of using the keystone transform. Furthermore, Radon transform in the squint mode will not give accurate results in determining the unambiguous Doppler centroid. Hence, in this paper, by using a Geometry-based Doppler centroid estimator, an approach is proposed to improve the precision of Radon transform which is capable to correct linear range migration. Finally, by employing local polynomial Fourier transform, Doppler parameters of order two and three are obtained. By estimating Doppler bandwidth, the target synthetic aperture time is then obtained. The accuracy of our derived equations is examined and verified by simulation just using a single antenna.