Weather Radar Raw Echo Data Compression Algorithm

Weather radar raw data is the primitive data of weather radar. It can be used to validate the veracity of the algorithm for radar product and reflect the information of aerosphere dynamic change, and it is also valuable for scientific research. But the amount of raw data of radar is so large with the use of weather radar frequently, that it is necessary to compress the raw data losslessly.Lossless compression methods are designed by the characteristic of weather radar raw data in the dissertation. Firstly, the overview and the signification of weather radar raw data compression without loss are summarized. Secondly, three principles of lossless compression methods are emphatically presented, including statistical modeling compression, dictionary-based compression and text-based compression. Thirdly, the property of the statistic and the correlation of real radar data are analyzed. Then, three kinds of lossless compression methods are designed according to the property of statistic and storage.The first kind of method is text-based compression algorithm, including bit mapping compression & Huffman, half-byte packing & Huffman, bit mapping compression & half-byte packing & Huffman.The second kind of method is binary system type data compression algorithm, including double Huffman, bit mapping compression & Huffman, double bit mapping compression & double Huffman based on zero threshold. Four kinds of integrated compression methods are derived from bit mapping & Huffman. They are bit mapping compression & Huffman, bit mapping compression & double Huffman, double bit mapping & Huffman, double bit mapping compression & double Huffman.The third kind of method is compression algorithm for switch data, including integrated compression algorithm based on the threshold of 28-1 and 216-1.Finally, these integrated compression methods are used to compress and decompress real raw data in C environment, and compared to traditional compression methods and popular compression software by compression factor, compression time and decompression time, the experimental result shows that the seven proposed methods are better than the traditional methods and the popular compression software, so the integrated compression methods are suitable to compress weather radar raw data losslessly.