Research On The Method Of Tracking Demodulation Performance Enhancement Of Ground Telemetry Equipment

Telemetry equipment which is an important part of the range tracking telemetry command and communication system is mainly responsible for the reception,demodulation and transmission of telemetry signals,which provide wireless communication channel for the test task,and it is an important part of the range tracking telemetry command and communication system.The data provided by telemetry equipment is the judgment source of several key parameters in the test task,and the data of low error rate and low number of frames are the basic guarantee for the accuracy of the interpretation.Capturing and tracking the target in time,accurately and steadily is the key and precondition for obtaining the correct telemetry data.When executing the test task,there are many problems,such as the difficulty of tracking between speediness and stability of servo system,the low synchronization efficiency and low synchronization performance caused by the change of the target flying posture,which often lead to more frames dropping at the key nodes of the target flight.Aiming at the problem of loosing telemetry data easily in the critical moment such as taking-off,stage-separation,fairing-separation and spin-up,the project researches the technology about servo tracking,signal processing and telemetry demodulation,which improves the ability to achieve telemetry data and enhances the tested performance of equipment.Firstly,the servo loop bandwidth model is constructed by using system identification method.Judgment criterion on loop bandwidth is determined through quantitative calculation.Based on the analysis of AGC closed-loop characteristics,the mathematical relationship between the data loss frame rate,target distance variation and angle error coupling and AGC time constant is established.A new bandwidth self-adapting method is developed,and tracking precision of servo is improved.The criterion in the setting of AGC time constant is established.The optimization method of AGC time constant is achieved in different task.Next,the logic judgment strategy between carrier synchronization and code synchronization is improved via analyzing lock thres hold of carrier synchronization and code synchronization.The ability to acquire telemetry data is significantly advanced in the large dynamic.Afterwards,the setting standard of optimal parameters on frame synchronization is constructed through analyzing the frame synchronization mechanism based on three state transition.The optimal selection of frame synchronization parameters is proposed by using theoretical calculation and traversal test.The optimal parameter combination is achieved in different length of frame synchronization code.Finally,the tracking precision of servo obviously improves,receiving and processing of signal is more stable,and the data frames loss significantly reduces when research results were applied into the space missions and weapons tasks.The research work has effectively improved the ability of telemetery equipment to obtain the telemetry data of the key flight nodes of the aircraft,and effectively enhanced the comprehensive performance of telemetry equipment.