The Design And Implementation Of Telemetry System Based On INS/GPS Data Fusion

Data fusion has been one of the core technologies in navigation field since 1970s.Based on INS/GPS integrated navigation,this paper studied the data fusion algorithm of INS/GPS system and designed to achieve the communication link and protocol of space telemetry system.The main tasks and achievements as follows:1.In order to improve the normalization and transmission efficiency of the data,the source packet and the format of transfer frame of the telemetry data in INS/GPS integrated navigation system were designed on the base of the subcontract telemetry spatial data link protocol of CCSDS data link layer.2.For the safety and efficient transmission of telemetry data,a telemetry communication link between Turbo code and CPM modulation mode was excogitated.The Turbo code has an excellent performance of error correction,power utilization of CPM modulation system and spectrum effectiveness with strong anti-interference ability are very high.The simulation results show that the Turbo-CPM telemetry system improves the channel gain of 2.5dB compared with the PCM-CPM telemetry system under the circumstance of the error bit rate of 1×10^-1.3.To solve the problem of divergence of conventional filter caused by the difficulty of estimate and measurement of noise statistical characteristics in data fusion,the sub-filter algorithm of the federated filter is improved.The statistical characteristics of observation information used by the improved algorithm which can simultaneously calculate the covariance of the system noise and the observed noise.The algorithm realize the on-line estimation of the statistical characteristics of the time-varying noise,which effectively suppresses the divergence of the filter.The simulation results show that the improved federated filter is more stable,also has better adaptability and higher positioning accuracy.4.The paper designed a complete telemetry system of INS/GPS system,which includes data encapsulation,transmission,fusion process,error solution and trajectory.The proposed federated filtering algorithm was used to telemetry and track measure of the air mobility platform.It verified the efficiency and had some of engineering application value.