Patent ID: 8049657
Filing Date: 2011-11-01
Classification: G01S

Abstract:
1. A method for processing TOPS (Terrain Observation by Progressive Scan)-SAR(Synthetic Aperture Radar)—raw data into highly accurate image data, characterized by two-dimensional processing of the TOPS-SAR raw data through a chirp scaling method and a baseband azimuth scaling method using a processor to carry out the following successive steps: a) subdividing the TOPS-SAR raw data into azimuth subaperture data ( b) performing a short-term azimuth FFT ( c) multiplying the signal by a chirp scaling function H  wherein f  λ is a wavelength, ν is the speed on the ground, K d) performing a range FFT for obtaining the signal in the two-dimensional frequency range ( e) multiplying the signal by the phase function H  for performing the correction of the range variation, of the range compression and of the secondary range compression, f f) performing a range IFFT so as to include the signal into the range Doppler region ( g) multiplying the signal by a phase correction function H  wherein r h) multiplying the two-dimensional data which are taken over in the range Doppler region and after performing the main steps of range compression and range variation correction of a target, by a phase function H  and r is the range vector, K i) transforming the subaperture data through short azimuth IFFTs back into the azimuth and range time domain ( j) joining the azimuth subapertures ( k) multiplying the two-dimensional data by a derotation function H  wherein t is the time vector in the azimuth direction and t l) transforming the derotated data through long azimuth FFTs into the range Doppler region ( m) subsequently, multiplying the two-dimensional data through an azimuth compression function H  is the effective chirp rate after the scaling and derotation operations, W(f n) transforming the data through a long azimuth IFFT into the image data ( o) multiplying the two-dimensional image data through a phase function H  to achieve a phase maintenance (