Research On Multi-Channel Telemetry Noise Data Lossless Compress Technology

The telemetry system of the wireless transmission channel has been difficult to meet thedevelopment of the telemetry system. Due to technical and budget constraints, bothdevelopment higher bandwidth telemetry communications equipment and increase theexisting bandwidth telemetry transmission chain are not appropriate solutions. While lookingfor a breakthrough from the source code, using data compression technology, just add datacompression unit inside an aircraft, without changing any other part of the telemetry system,can improve the channel utilization to a certain extent, reduce the pressure on datatransmission, relatively, such a measure is the most economical, most efficient most flexible,and risk minimization.Contrast of several commonly used lossless compression algorithm for telemetry noisedata in two aspects: time and space performance of lossless compression algorithm, eachalgorithm in the compression space performance needs to be improved. Discussion theprinciple of predictive coding how to improved the removing rate of compression, usingfirst-order difference prediction coding to improve the compression algorithm, analysis andcontrast the time and space performance of various improved algorithms, Selected thearithmetic coding by first order differential prediction——D_ARC algorithm，although in thecapability of space is not the best, but the better time performance, more suitable formulti-channel data compression. Research and improve the channel bit error diffusion causedby the introduction of the compression algorithm.For the reliability requirements of Aerospace telemetry system, and the large amount ofdata characteristics of multi-channel data compression, combined with the technical indicators,from the point of data acquisition, data communication interface and data buffer design a highperformance, high reliability, low development costs of the hardware realization scheme. Discussed the key issues encountered in the unit design process in the multi-channeltelemetry data compression: isolation data compression unit and telemetry system withOptocoupler to prevent affect the telemetry system for single fault, preset differential value tothe4channel quantitative data buffer ensure4channel noise compression uniform and stable,improve the efficiency of the algorithm and the reliability of data compression unit. Usingasynchronous serial communication way to transmission the compression data betweenasynchronous clocks in high-speed.Using stand-alone test device verify the functionality and reliability of data compressionunit. The experimental results show that all the technical parameters of multi-channeltelemetry data compression unit have reached the predetermined indicators.