Study On Data Preprocessing For Satellite Radar Altimeter

Satellite radar altimeter plays an important role in marine research. Through the post processing for the data of altimeter, the anticipated ocean parameters can be obtained, such as range, significant wave height, backscatter coefficient, and etc.In this thesis, the flow of the data preprocessing for altimeter is analyzed, and in which the key component, ocean retracking, is studied in detail. To realize the correction of point target response and weight window, the Hayne's model for ocean retracking is modified, and the new retracking model can correct effectively both the distortion of the point target response and the influence coming from the weighting window. The new retracking model is utilized in the data preprocessing for SZ-4 altimeter, and the results show that this approach is more effective than the original Hayne's mode.There are three aspects in this thesis:(1) The flow of the on-ground data processing for altimeter is analyzed, and both the function and the implementation of the data preprocessing are studied.(2) Some key technologies concerning ocean retracking, such as waveform model, the method for parameter estimation, and simulation experiments, are investigated.(3) To correct the distortion of the point target response and the effect of weighting window utilized in the tracker on board, a new modified Hayne's model is brought forward, and in which these two factors are imported to the ocean retracking. The data of SZ-4 altimeter are processed by this method, and the results show that this method is effective for improving the accuracy of the estimates.