Anti-saturation block adaptive quantization algorithm for the whole set of saturation degree’s SAR raw data compression

Inhalt:
In order to improve the performance of Block Adaptive Quantization (BAQ) when the output of Analog to Digital Convertor (ADC) is saturated, this paper proposes an anti-saturation block adaptive quantization algorithm. Firstly, the concept of the Standard Deviation of the Output Signal (SDOS) of ADC is proposed. Then, different from traditional normalization processing, SDOS is utilized and the mapping between SDOS and the average signal magnitude is deduced. Secondly, the saturation term to Lloyd-Max quantizer is introduced and the optimal nonuniform scalar quantizer for saturated SAR raw data quantization is proposed. After that, the implementation scheme of the new algorithm by FPGA is detailedly analyzed. Lastly, the relationships among the saturation degree of the signal, peak-to-peak value of ADC, standard deviation of the input and output signal of ADC and the average signal magnitude are deduced. Based on those relationships, power compensation decoder is designed for encoding. Numerical experiments’ results based on ERS-1 and simulated data show that the performance of the new algorithm is better than that of BAQ.