In SAR digital data processing, using the rangeDoppler approach, the main computational load occurs in the range and azimuth compressions, for which one-dimensional circular convolutions in the Fourier domain are exploited. In this case, the raw-data compressions can be pipelined by means of two independent processors, one for the range and the other for the azimuth direction. From the algorithmical point of view, the inherent structure of the multidimensional DFT algorithms used for fast convolution suggests that their computation too could be distributed to nodes of a multiprocessor system. The paper shows as the outlined principles can be exploited to perform up to the real-time SRR data focusing, by means of flexible multiprocessor architectures based on advanced components with interconnection capabilities.

A modular digital SAR exploiting the range-doppler been developed .and tested both simulated SAR raw-data.processor, approach, has on real and

I s t i t u t o Elaborazionle Segnal i ed Immagini ~ IES I /CNR-Bar i (") Dipartimento di E l e t t r o t e c n i c a ed E I e t t r o n i c a -U n i v . d i B a r i (+) C a l i f o r n i a lnsti t u t e of Technoilogy. Pasadena-CaI i f o r n i a (USA)

In SAR digital data processing, using the range‐Doppler approach, the main computational load occurs in the range and azimuth compressions, for which one‐dimensional circular convolutions in the Fourier domain are used. In the paper it is shown how the intrinsic degrees of parallelism of the process can be efficiently exploited to design a flexible parallel/pipeline multiprocessor architecture, based on advanced components with interconnection capabilities and capable to perform up to the real‐time SAR data focusing. In the proposed architecture, an efficient line compression can be achieved by means of pipelined processors for the range and the azimuth compressions and many of these structures, each performing the compression of a line or its section, can be used to sustain the computational load and the data rate requirements. In the paper, we also show how the data communication between the range and the azimuth processors can be solved when a maximum of eight of these line compressors are used. The performance evaluation of the proposed architecture is made referring to real spaceborne SAR sensors.

No abstract