| Distributed network of Doppler Weather Radar System is constituted by multiple radar sites. The detection area is coincident and communicating with each other to further improve the warning capabilities of disaster weather. However, several radars generate enormous amount of radar raw data which is not suitable for network transmission. Therefore, data compression algorithm in this network of distributed solid state weather radar system is studied for the purpose of reducing the data transfer rate. Research is carried out as follows:(1) Based on studying the weather radar raw data format, simulation and analysis experiments are carried out from time domain, frequency domain, correlation property and entropy property to the raw data for mining data features.(2) Combined with the characteristics of raw data, lossless compression algorithm based on context model is studied. The improved algorithm is proposed after comparing the result of compression experiments.(3) The idea of reducing noise using wavelet transform modulus maxima(WTMM) method for weather radar echo data is studied, combining with features of the original echo and the improved lossless compression algorithm, a mixed data compression system based on WTMM denoising is given and simulation results is shown.(4) Calculating compression ratio and SNR ratio from the point of base data (strength, speed, spectral width) to assess the distortion. Experimental results show that the proposed algorithm can compress raw data efficiently under the premise of a certain distortion. |
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