Synthetic aperture radar (SAR) is an imaging technique, which provides high-resolution images. The high resolution in the range direction is achieved by using large bandwidth signals and that in the azimuth direction is achieved by synthesizing a large aperture antenna using platform motion. The unique data collection geometry of SAR system requires that huge amounts of raw data be processed before obtaining a viewable image. Therefore, performing some form of compression on SAR raw data provides an attractive option for SAR systems. Block Adaptive Quantizer (BAQ) has been a very attractive method for compression due to simplicity in its on-board implementation and less hardware complexity. Analog-to Digital Converter (ADC) is an integral part in this compression process. Since the SAR raw data has very wide dynamic range, the ADC gets saturated at higher average value of the input signal . The higher value saturates ADC causing loss of power. In the present paper we have suggested a technique to compensate this power loss and restoring the Gaussian nature of the SAR data.

1. P.S.Cooper,”ADC saturation effects and pointbtarget calibration,” Proceedings of CEOS SAR calibration Workshop, 28-30 september 1994, pp38-50.
2. P.J.Meadows and P.A.Wright,”ERS-1 SAR analogue to digital converter saturation,” in Proceedings of CEOS SAR Calibration Workshop,28-30 september 1994,pp24-37.
3. J.Nicoll,R.Gens and P.Denny,”Pre-processing compensation for saturation power loss in SAR data,” in Proceedings of IEEE International Geoscience and Remote Sensing Symposium,IGARSS 2002,vol.5.pp.2744-2746.
4. H. DonghuiH. ,Zhou. and H.Wen, “Correction method for saturated SAR data to improve radiometric accuracy,” in Proceedings of IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2005,pp.3344-3347.
5. J. Max, “Quantization for minimum distortion,” IEEE Transactions on Information Theory, vol. IT-6, pp.7-12, 1960
6. M.Shimada,M.,” Radiometric correction of saturated SAR data”,in IEEE Transactiuons on Geoscience and Remote sensing,vol.37,no.1,pp.467-478.1999.

Synthetic aperture radar (SAR) A/D converter saturated data restoration