GPS L1频点授权信号质量评估

GNSS信号的空间信号(SIS)质量直接影响用户的定位、测试和授时(Positioning, Velocity and Timing, PVT)服务精度，但由于授权信号保密等原因，授权信号的伪码序列未知，卫星导航系统授权信号质量评估存在一定的困难性。该文主要分析GPS BIIF-5卫星L1频点的相干自适应副载波调制(CASM)信号，利用匹配滤波理论恢复出采集数据中的P(Y)码和M码两个授权信号分量的伪码符号，采用极大似然估计结合信号分布特点准确求解出各信号分量之间的功率分配。重点分析P(Y)码和M码信号相关性能，包含相关曲线、相关损失和S曲线过零点偏差(S-Curve bias)，定量地评估了授权信号的空间信号质量。提出完整的基于GPS L1频点授权信号质量评估方法，研究成果可作为其他卫星导航系统授权信号质量评估的参考。

Authorized Signals Quality Assessment on GPS L1

The quality of Signal-In-Space (SIS) for Global Navigation Satellite System (GNSS) is directly linked to users Positioning, Velocity and Timing (PVT) service. Limited to the insensitivity of authorized signals, the pseudo codes can not be obtained, so it is difficult to assess the authorized signal quality. This paper mainly focus on analyzing the Coherent Adaptive Subcarrier Modulation (CASM) signal on L1 frequency points for GPS BIIF-5 satellite and the code sequences of P(Y) and M signal are resumed by using matched filtering technology. The power distribution of each signal component can be solved through the maximum likelihood estimation theory combined with the signal characteristics. This paper laies special stress on quantitatively analyzing the correlation performance on P(Y) and M signals, including correlation curve, correlation loss and S-curve biases. Based on this complete authorized signals quality assessment method for GPS L1, the research productions can be reference to other satellite navigation systems authorized signals.