Algorithm And Implementation Of GPS Data Compression Based On Huffman Coding

The vehicle-carried GPS (Global Positioning System) system is generally composed of the GPS satellite signal receiver, the Micro Controller Unit (MCU), the wireless communication module, the memory and the display device. Small capacity Flash Memory is usually chosen as storage device of the vehicle-carried GPS system in consideration of cost as well as volume. However, in order to provide the travel tracks replay for the control center, the vehicle-carried GPS system must save massive positioning data. These data also must be transmitted to the control center through the GSM/GPRS network. The transmission requires high expenses and is limited by the band width of network. As a consequence, the performance of the vehicle-carried GPS system is heavily affected.According to the characteristics of GPS data, this article suggests to use Huffman coding to compress preprocessed GPS data. The actually measured compressing ratio of this algorithm is not less than 78%. With less programming time but more compressing ratio, this algorithm is easier to be implemented compared to prevailing data processing method in use. And the algorithm makes important sense in practice to solve the problem of storing a large number of data within limited system memory in vehicle-carried GPS, and to break the bottleneck of data transmission.Finally, this article proposes a design scheme of embedded file system. Being easy and feasible, this scheme is suitable for the vehicle-carried GPS system. And this scheme makes preparation for the operation of data file, the management of memory as well as transplant of the compression algorithm mentioned in this article. The further development of vehicle-carried GPS system can be based on this scheme.