Research On Space-Time Coding Technology Of New Telemetry Launch System

Currently,the International Telemetry Organization’s IRIG106 standard proposes a modulation scheme that combines Alamouti coding with SOQPSK＿TG modulation.When applied to a dual-antenna telemetry transmission system,it effectively solves the "dual-antenna interference problem." Additionally,compared to traditional PCM/FM systems,the SOQPSK＿TG new system has a higher bandwidth utilization rate and meets the high-rate telemetry requirements of space telemetry.Based on current research background,this thesis focuses on implementing this telemetry transmission system on the ZYNQ platform equipped with the AD9361,which satisfies the requirements of small equipment size and low power consumption for telemetry transmission devices,while relying on software programmability to meet different communication standards and improve equipment versatility.Firstly,the technical index and overall scheme design of the telemetry transmission system are proposed,and a comparison of common baseband processing chips and RF transceivers is made,determining the core chips of this design.On this basis,the hardware circuit design of the telemetry transmission system is realized,including peripheral circuit designs such as power supply circuits,clock circuits,flash storage circuits,RF front-end circuits,as well as interface circuit designs for data exchange and control between chips,including LVDS data interface and SPI control interface designs.Secondly,the software design of the telemetry transmission system is implemented,including baseband and RF aspects.The baseband processing part completes the Verilog program writing for the space-time coding module,precoding module,phase calculation module,and waveform generator module,generating two I/Q format digital baseband signals.The RF processing part completes the AD9361 register configuration,SPI interface,and digital data interface driver program design and verifies the correctness of each module design through Modelsim simulation.Finally,a telemetry transmitter test platform is built,and the signal waveforms of each module are collected using an online logic analyzer Chipscope to verify the functionality of encoding and modulation.A vector signal analyzer is used to collect an Alamouti-SOQPSK＿TG coded modulation signal,observing that the RF center frequency is 2.2GHz,and the corresponding 99% energy bandwidth for a code rate of10 Mbps is 7.67 MHz,with only a 1.66% error compared to the theoretical value in the IRIG106 standard,verifying that the telemetry transmission system can send signals normally and meet the high-rate code rate requirements,providing a reference for engineering applications.