Doppler centroid frequency is an essential parameter in the imaging processing of the Scanning mode Synthetic Aperture Radar (ScanSAR). Inaccurate Doppler centroid frequency will result in ghost images in imaging resu...Doppler centroid frequency is an essential parameter in the imaging processing of the Scanning mode Synthetic Aperture Radar (ScanSAR). Inaccurate Doppler centroid frequency will result in ghost images in imaging result. In this letter, the principle and algorithms of Doppler centroid frequency estimation are introduced. Then the echo data of ScanSAR system is analyzed. Based on the algorithms of energy balancing and correlation Doppler estimator in the estimation of Doppler centroid frequency in strip mode SAR, an improved method for Doppler centroid frequency estimation in ScanSAR is proposed. The method has improved the accuracy of Doppler centroid frequency estimation in ScanSAR by zero padding between burst data. Finally, the proposed method is validated with the processing of ENVIronment SATellite Advanced Synthetic Aperture Radar (ENVISAT ASAR) wide swath raw data.展开更多
The linear relationship between Doppler centroid and range walking in spaceborne SAR data is analyzed, and a new method to estimate Doppler centroid is proposed, which is so called amplitude correlation method. Compar...The linear relationship between Doppler centroid and range walking in spaceborne SAR data is analyzed, and a new method to estimate Doppler centroid is proposed, which is so called amplitude correlation method. Compared with clutter-lock method which is widely used now, the new method has much less computation burden and is able to give higher estimation accuracy for a quasi-homogeneous scene or a non-homogeneous scene. This is clearly verified by the experimental results of estimating Doppler centroid for SEASAT-A raw data.展开更多
文摘Doppler centroid frequency is an essential parameter in the imaging processing of the Scanning mode Synthetic Aperture Radar (ScanSAR). Inaccurate Doppler centroid frequency will result in ghost images in imaging result. In this letter, the principle and algorithms of Doppler centroid frequency estimation are introduced. Then the echo data of ScanSAR system is analyzed. Based on the algorithms of energy balancing and correlation Doppler estimator in the estimation of Doppler centroid frequency in strip mode SAR, an improved method for Doppler centroid frequency estimation in ScanSAR is proposed. The method has improved the accuracy of Doppler centroid frequency estimation in ScanSAR by zero padding between burst data. Finally, the proposed method is validated with the processing of ENVIronment SATellite Advanced Synthetic Aperture Radar (ENVISAT ASAR) wide swath raw data.
文摘The linear relationship between Doppler centroid and range walking in spaceborne SAR data is analyzed, and a new method to estimate Doppler centroid is proposed, which is so called amplitude correlation method. Compared with clutter-lock method which is widely used now, the new method has much less computation burden and is able to give higher estimation accuracy for a quasi-homogeneous scene or a non-homogeneous scene. This is clearly verified by the experimental results of estimating Doppler centroid for SEASAT-A raw data.
