Multi-symbol Detection Algorithm And Receiver Implementation In Telemetry

In the development of modern national defense,telemetry system plays an important role in the development and test of important military weapons,such as missiles,artillery shells,rockets,etc.among various telemetry systems with different signal modulation modes,PCM/FM(Pulse Code Modulation/Frequency Modulation)telemetry system is most widely used.At present,due to the continuous growth of telemetry distance and telemetry rate,the R&D personnel need to improve the receiving performance of the receiver according to the coming actual needs.In addition,in the actual range test,the receiver is very cumbersome,which brings many difficulties to the field test,so in order to meet the needs of users,the receiver needs a higher degree of integration.To sum up,in the research and improvement of telemetry receiver,we should not only study how to improve the receiving performance of the receiver,but also study how to reduce the volume and weight of the receiver.The thesis relies on actual engineering projects and aims to design and implement portable telemetry receivers capable of carrying multi-symbol detection functions.The research work has the following aspects:1.The multi-symbol detection algorithm which can improve the receiving performance of telemetry receiver is studied.Firstly,the decision criteria and the principle of multi-symbol detection are deduced and summarized,and then the algorithm complexity of multi-symbol detection is analyzed and calculated.The next point is to use MATLAB software to carry out Monte Carlo simulation for the multi-symbol detection algorithm of three symbol intervals,including 3 symbols,5 symbols and 7 symbols,so that the advantages and disadvantages of three different detection symbols can be comprehensively compared by combining the performance gains of simulation results and the analysis results of algorithm complexity.Finally,according to the results of the comprehensive comparison,the detection interval suitable for hardware implementation is selected,that is,the detection interval of 5 symbols.2.A portable zero-IF receiver is designed and implemented.Firstly,the function analysis and schematic drawing of RF unit,baseband unit and battery management unit are carried out,then the PCB(printed circuit board)is drawn,and finally the telemetry control management unit of the receiver is described.The core functional module of the zero-IF receiver is the agile transceiver board of AD9361 and it is a miniaturized functional module combined with FPGA(Field Programmable Gate Array)chip.It is responsible for completing the A/D conversion,mixing,modulation and demodulation of radio frequency signals and other functions.3.After the research of multi symbol detection and the design and implementation of receiver,the receiver is tested for receiving frequency,sensitivity and code rate.The emphasis is on the sensitivity test,and the gain of the receiver before and after the multi symbol detection and demodulation is compared.The results show that the 5-symbols multi-symbol detection can improve the gain of 2-3dB compared with the traditional frequency discrimination and demodulation.In conclusion,this thesis studies the multi-symbol detection algorithm,which lays a theoretical foundation for improving the demodulation performance of telemetry receiver.Through the research and design of the zero-IF receiver,it not only provides a carrier for the engineering realization of the multi symbol detection algorithm,but also provides an important idea for the miniaturization of the telemetry receiver,and accumulates important experience for its highly integrated development direction.Finally,the performance test of the receiver verifies the performance improvement of multi-symbol detection,and proves that the function and performance index of the zero-IF receiver can meet the requirements of general telemetry tasks.