基于GNSS的地基增强系统信号质量监测阈值设计

Design of SQM Threshold for Ground-Based Augmentation System Based on GNSS

针对载噪比和码/载波分歧监测量在信号质量监测(SQM)过程中出现的非高斯性导致阈值模型过于保守的问题,提出一种基于稳定分布的SQM监测量参数阈值算法。首先给出2种监测量基于高斯分布的阈值模型,然后推导基于稳定分布的监测量阈值模型,最后通过实测数据对稳定分布的阈值算法进行评估与验证。结果表明,稳定分布可更加准确地描述载噪比和码/载波分歧监测量,使阈值更加紧致地包络监测量参数,从而解决传统阈值模型过于保守、精确低的问题,降低系统风险,提升GBAS系统的完好性。

Aiming at the problem that the threshold model is too conservative due to the non-Gaussian features of the CNR and CCD monitoring quantities in the signal quality monitoring(SQM)process,we propose a threshold algorithm for SQM based on stable distribution.Firstly,we give two threshold models based on Gaussian distribution,and then derive the threshold model of monitoring quantities based on stable distribution.Finally,we evaluate and verify the threshold algorithm based on stable distribution by the measured data.The results show that the stable distribution can more accurately describe the CNR and CCD monitoring quantities,making the threshold envelope the monitoring quantity parameters tighter,solving the problem of the practical threshold model being too conservative and insufficiently accurate,reducing the risk and improving the integrity of the GBAS system.