干扰源双星定位中的邻星同频干扰解调对消方法

Adjacent Satellite Co-channel Interference Cancellation Based on Demodulation in Dual-satellite Location System

干扰源双星定位系统中邻星存在同频干扰,导致目标信号信噪比过低,利用互模糊函数估计时差、频差时,检测不到相关峰,无法完成参数提取,为此,提出了一种基于解调对消的干扰抑制方法,通过信号参数估计、调制识别、解调重构、时间同步、相位幅度补偿和相减抵消等步骤,削弱干扰信号的功率,提高目标信号的信噪比,使得同样的处理增益下相关峰值明显高于噪底。仿真结果表明该方法能够逼近理论下界,实现干扰条件下的定位参数提取,有效拓展了双星定位系统的适用性。

Aiming to the problem that the SNR of target signal is too low to estimate the TDOA （Time Difference of Arrival） and FDOA （Frequency Difference of Arrival） for location when there is a co-channel interference on the adjacent satellite in dual-satellites location system, an interference cancellation method is proposed, which weakens the power of the interference through the steps such as parameter estimation, modulation recognition, demodulation and reconstruction, timing and compensation of phase and amplitude, without any beforehand information, to improve the SNR of target signal to make the correlation peak of CAF （Cross Ambiguity Function） be detected. The simulation results show it can approach the theoretical lower bound and realize the estimation of location parameters, so as to expand the applicability of the dual - satellites location system.