AM-AM变换对卫星跟踪和数据中继DOA估计的影响

摘要： 在跟踪和数据中继卫星系统反向链路中，多路频分复用信号通过高功率放大器时存在严重的交调干扰，导致输出的各路阵元信号严重失真. 针对这一问题，该文通过幂级数模型分析高功率放大器调幅-调幅(AM-AM)变换对通道间幅度一致性的影响机理，建立幅度不一致性对波达方向(direction of arrival, DOA) 估计影响的数学模型，并进行计算机仿真. 理论分析和仿真结果表明：高功率放大器的AM-AM变换不会引起估计角度的偏移，但会导致空间角度范围内的谱峰值降低，同时使3 dB 谱宽变宽. 此外，AM-AM变换还会导致DOA估计性能恶化.

Effects of AM-AM Conversion on DOA Estimation in Tracking and Data Relay Satellite System

In the reverse link of tracking and data relay satellite system (TDRSS), AM-AM conversion in the high-power amplifier for frequency-division multiplexing (FDM) signals causes severe inter-modulation interference to the signals in different channels. The interference results in distortion of the channel signals. The present work uses power series to analyze the influence of AM-AM conversion on the amplifier’s magnitude consistency among the channels, and establish a mathematical model of the influence of magnitude inconsistency on DOA estimation. Theoretical analysis and simulation results show that AM-AM conversion in high-power amplifier does not affect the offset of the estimated angle, but reduces the spectral peak within the spatial angle and increases the 3 dB bandwidth. AM-AM conversion also deteriorates the DOA estimation performance.