基于多参数稳定分布的GBAS垂直保护级计算

Calculation of GBAS vertical protection level based on multi-parameter stable distribution

针对全球导航卫星系统(global navigation satellite system,GNSS)的地基增强系统(ground based augmentation system,GBAS)的完好性评估过程中,使用误差包络理论计算保护级(protection level,PL)时,误差模型存在的“厚尾”“不对称”“非零均值”等问题,提出了基于稳定分布的误差包络理论。首先给出了高斯包络理论计算PL的模型;其次推导了两参数与四参数稳定分布误差包络算法;最后使用仿真数据和通过实验测得的数据,对多参数稳定包络模型的算法进行评估。结果表明多参数稳定包络法在相似的计算复杂度下,解决了高斯包络法建模时过于保守的问题,显著提高了保护级计算的精确性。

During the integrity assessment of the ground based augmentation system(GBAS)for the global navigation satellite system(GNSS),the error overbounding method is used to calculate the protection level(PL).To solve the problems of“thick tail”,“asymmetric”and“non-zero mean”appearing in the error model,a method based on stable distribution is proposed to overbound the GBAS error.Firstly,the traditional calculation methods and research status are introduced.Secondly,the algorithm of the overbounding error through multi-parameter stable distribution is derived.Finally,the simulation model data and measured data are applied to analyze the error model and calculate the PL by the use of the multi-parameter stable overbound model.The results show that the stable overbound model solves the problem of over-conservativeness in modeling with the Gaussian overbound method under similar computational complexity,and significantly improves the accuracy of PL calculation.