非正态分布假设下的完好性阈值计算与分析

Calculation and Analysis on Integrity Threshold Based on Non-Gaussian Distributing

引入"概率包络"概念,从分析复杂多路径误差的概率分布入手,推导了两种非高斯分布的多路径误差概率分布模型,改进了两种基于污染正态分布的完好性阈值计算方法,并分别在伪距域和定位域对非高斯误差分布模型进行高斯概率包络分析,计算相应的均方差膨胀因子,从理论上体现了完好性阈值计算方法的严密性和有效性。仿真计算结果表明,两种改进的完好性阈值计算结果都能够对污染正态分布误差模型实现高斯概率包络,但第一种改进方法计算结果相对比较保守,第二种改进方法计算结果更加优化。

The precondition of integrity calculating equation is usually based on the Gaussian distribution for pseudo range errors. When the assumed Gaussian distribution of range error is contaminated, the calculation results will not protect user position error anymore which will result in additional integrity risk. The integrity equation based on Non-Gaussian distri- bution was proposed and analyzed. The definition of probability overbounding and two mod- els of multipath errors were introduced. A Gaussian distribution was adopted to overbound the probability of the Non-Gaussian distribution , and the new inflation variance scale was calculated to substitute the variance scale based on Gaussian distribution. The integrity equa- tion was calculated using the new variance scale to gain a safer vertical protect level and hori- zontal protect level avoiding the additional probability of hazard mislead information and make the integrity equation to be more rigorous in theory. Through the simulation and anal- ysis it is shown that both of the improved integrity equations could Gaussian probability overbound the error which is contaminated, and the first improved equation is more conser- vative than the second one, and the second improved equation is more optimal and lead to a better availability and continuity.