| 摘要 |
For the imaging of terrains with varied ground reflectivity, azimuth spectra continuously following each other in time are formed over a set period of time in a method for extracting motion errors of a platform carrying a coherent imaging radar system from raw radar data. By determining the position of the maximum of the correlation between two azimuth spectra formed immediately following each other in time, the frequency shift of the ground reflectivity part is obtained. Then a separation of a velocity Vv(t) in the forward direction from an acceleration Vb(t) in the direction of LOS of the antenna is performed by filtering and the acceleration Vb(t) obtained is subjected to normalization after two-fold integration, by means of which the displacement in LOS, i.e. the motion errors in the line of sight direction of the antenna, is obtained. In contrast to GPS systems, all information is taken from the raw radar data and no ground station is required, so that the present method can be used much more flexibly and is more self-sufficient. Furthermore, in comparison with the autofocus method, the present method has a much greater band width and can be performed in real time, which cannot be realized with the autofocus method.
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