Research On Lossless Data Compression Of Remote Monitoring System For Vehicle

With the development of the remote monitoring system of vehicles,the function of the vehicle remote monitoring of the system is also growing.Car GPS system the amount of the date is also will become larger. As the GPS system, increasing the amount of data, resulting in the GPRS transmission costs also increased. In order to reduce costs, improve GPS vehicle system data transmission efficiency and reduce vehicle remote monitoring data from the pressure side. This paper presents a GPS positioning system data structure for lossless compression.First, this paper introduced the basic concepts of information theory, also introduced the basic concepts of data compression, data lossless compression and lossy compression in the concept. In this article, the choices are lossless data compression, because the GPS data is different from the pictures, videos, pictures and video to lossy compression may be some visual loss, but the judge is not out of the general eye. Lossless data compression for GPS data, GPS data if the encoding and encoding time if the data is lost, the location of the final form data bias.After studying the GPS function of the various statements after. GPS option in the statement we selected RMC statement. RMC statement focused on the vehicle latitude and longitude, speed and direction. Under normal circumstances the system used in the car this statement is the most.RMC statement selected compression. According to RMC sentence structure, the research pre compressed. Compression pre processing RMC statement prefix, location status, latitude and longitude and other symbols. After pretreatment, after the basic compression, GPS data can remove the English character data, GPS data after the preprocessing only these ten numbers 0 to 9, further compression of the very important role.As the GPS data compressed only after pretreatment of these ten numbers 0 to 9. So that we can choose the compression data structure consistent with this approach. Having studied the principle of Huffman coding, the decision to select the Huffman coding to compress.Huffman coding theory in the study after the draw with Huffman coding steps. Mainly the frequency of the source data, calculations, to establish Hoffman binary tree, binary tree based Huffman encoding.Some data in the receiving GPS data, for compression testing. After pretreatment in the compressed GPS data compression ratio up to 50%, for Huffman coding of single words can reach 48% compression ratio. In the data pre-processing carried out after Huffman coding, GPS data compression ratio can reach 75%. It can be said that this compression method is very effective.After testing, also describes the composition of vehicle remote monitoring system. Vehicle remote monitoring system is divided into front and back, front is mainly used GIS (digital map) system to the remote monitoring of vehicle, location, tracking and other functions. Background is mainly used for data processing SQL software.GPS data and then introduces the test environment. This article is within the positioning using P800 chip SiRF Star III, SiRF Star III chip is a chip for the GPS positioning system. With GPS positioning function. Reuse GPSgate software, SiRF Star III GPS chip receives data to be compressed into the computer and test.Finally, summarize the content of this article summarizes the proposed GPS data compression method that the advantages and disadvantages. Also on the vehicle remote monitoring system, GPS systems, GPS prospect data compression method.