Design Of Miniaturized Missile Telemetry System Based On AD9364

Telemetry communication technology plays an indispensable role in my country’s aerospace and national defense construction.Due to the limitation of frequency bandwidth,power and modulation method,the code rate of domestic general telemetry systems is generally around 2～5Mbps,and a high code rate system of more than 10 Mbps is urgently needed to meet the current demand.In response to the demand for high code rate,this paper designs a software radio zero-IF telemetry system based on AD9364 by comparing the current telemetry system,with the PCM/QPSK telemetry system with high frequency band utilization and strong antiinterference ability as the core.The specific research contents of this paper are as follows: In the transmitting part,a square root raised cosine roll-off filter is designed,which further improves the transmission efficiency of the system and the ability to resist inter-symbol interference by filtering out the baseband high-frequency harmonic signals.In the receiving part,an improved polar Costas loop demodulation method is innovatively proposed.By adding a virtual Q path,the Cordic algorithm is used to solve the phase detection error caused by the amplitude change,and the phase detection error is effectively improved.Accuracy,reducing the difficulty of receiver design;Secondly,this paper applies the design of the loop filter in the GPS receiver to the telemetry receiving system,which subtly solves the problem of fast tracking and locking of the receiver in a high dynamic environment.After completing the verification of the above algorithm,configure the corresponding registers of AD9364 through the PS（Processing System）terminal on the ZYNQ platform to realize the dynamic configuration of parameters such as system sampling frequency,sending and receiving frequency points,and working bandwidth;Use PL（Programmable Logic）terminal to realize the programming of QPSK modulation and demodulation module,bit synchronization and frame synchronization module,baseband data interface and other modules.By integrating the shaping filtering technology,the frequency locking-phase locking technology and the PCM/QPSK modulation and demodulation technology,it is comprehensively applied to the design of the missile-borne telemetry system,which further improves the stability and reliability of the telemetry system.Finally,the hardware test platform of the entire missile-borne telemetry system is built,and the single-carrier test and the actual communication test of the missile-borne telemetry system are carried out.The test results show that when the transmitting frequency point is S band,the code rate of the telemetry system designed in this paper can reach 10 Mbps,the frame error rate of the system is 0.0061%,and the communication distance can reach 15 km,which verifies that the telemetry system meets the design requirements of high code rate and has high reliability.To a certain extent,it promotes the research on the telemetry modulation system,and has certain reference significance for the development of the high code rate missile-borne telemetry system in our country.