基于改进的包络模型的GBAS完好性评估方法

Verification of GBAS Integrity Based on Improved Tail Overbounding Method

针对地基增强系统(GBAS)保护级完好性评估过程中包络模型阈值不确定的问题,本文利用非参数假设检验方法对给定阈值下的尾部包络模型进行检验,并将计算得到的P值作为选择最优阈值的依据,阈值的置信区间通过自助法(Boot Strap)计算得到。仿真实验分析了阈值变化对完好性风险的影响以及不同检验方法的检验效果。与传统包络方法相比,基于非参数假设检验方法计算的包络模型参数能够更加准确地描述样本尾部分布特征,且计算出的完好性风险值更加稳健。

Focusing on the problem of threshold uncertainty in tail-overbounding model, non-par hypothesis test method was adopted to evaluate the fitness of threshold which was the key to obtain a reliable estimation of GBAS protection level integrity risk. The P value calculated from the test was used to choose the best threshold and bootstrap method was taken to compute its confidence interval. Simulation based on a standard error model discussed the influence of various thresholds on integrity risk and the performance of different test methods were compared. Results also show that： compared with traditional tail-overbounding method, the model with threshold chosen by hypothesis test gives a more accurate description on tail samples and the corresponding integrity risk value proves to be more stable when threshold varies in its confidence interval.