Analysis And Solutions On The Effect Of Non-linearity In Reverse Link Of TDRSS

As a novel space-based tracking, telemetering and command system, Tracking and Data Relay Satellite System (TDRSS) represents a new direction in the TT&C Communication Technology, whose"space-based"design point resolve the problem of how to increase the coverage rate of the mediate/low orbit aircraft and decreasing the amount of ground telemetry stations. So TDRSS plays an important role in Satellite Communications System, and has wide application prospects.In order to reduce the difficulty of the design of relaying satellite, the Frequency Division Multiplexing technology is adopted to transmit the signal to the ground telemetry stations, in which the complicated process,such as DBF, is done, and this is just called sub-satellite DBF technology. High power amplifier is needed to transmit the signal to ground telemetry stations. Owing to the nonlinearity of HPA, the multi-channel FDM signal serious inter-modulate, which make the DBF performance to be deteriorated.In this paper, mathematics and computer simulation are used to analyze how nonlinear distortion in High-power amplifier affects the DBF performance, and an adaptive equalization method is presented to compensate the deterioration of DBF.The main research contents and contributions are as follows:1) The nonlinear distortion of high power amplifier in TDRSS is studied, as well as how AM-AM conversion and AM-PM conversion affect the magnitude consistency and phase consistency of 30 path FDM signal is analyzed.2) TDRSS reverse link based on sub-satellite is studied, as well as how AM-AM conversion and AM-PM conversion affect the performance of DBF is analyzed.3) The solution of nonlinear distortion and the possibility of compensating for nonlinear distortion by using adaptive equalizer are studied. Theoretical analysis and simulation results show that adaptive equalization is able to compensating for nonlinear distortion.