Systems Engineering and Electronics ›› 2020, Vol. 42 ›› Issue (10): 2294-2302.doi: 10.3969/j.issn.1001-506X.2020.10.18

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Integrity risk allocation of GBAS protection level using Bayesian decision

Yude NI1,2(), Xizhi LIU1(), Chujia CHEN1()   

  1. 1. College of Electronics Information and Automation, Civil Aviation University of China, Tianjin 300300, China
    2. Key Laboratory of Airworthiness Certification of Civil Aviation Aircraft, Civil Aviation Administration of China, Tianjin 300300, China
  • Received:2019-09-06 Online:2020-10-01 Published:2020-09-19

Abstract:

The integrity risk is one of the important indexes to describe the integrity of navigation systems. The missed multiplication factor and the protection levels of groud-based augmentation system (GBAS) can be calculated according to the protection level integrity risk assigned to the H0 and H1 hypotheses based on the number of the reference sites of categroty Ⅰ GBAS, mentioned in the standard DO-245A of the American Radio Technical Commission for Aeronautics (RTCA). This method fails to allocate the integrity risk probability based on the fault conditions of the reference sites, resulting in the protection levels not accurately reflecting the positioning errors of the GBAS. In this paper, the probability of the integrity risk is reallocated for the H0 and H1 hypotheses based on the minimum total error rate criterion utilizing the Bayesian decision. The integrity risk probability allocation is simulated and analysed for the conditions of different number of the reference sites and different error distributions, and the missed multiplication factor and vertical protection level are calculated, the results show that the values of the protection levels are reduced based on the integrity allocation algorithm of the Bayesian decision when the number of reference sites is greater than 2 and the vertical position errors obey the zero-mean or non-zero mean Gaussian distribution. Theoretical analysis and simulation experiments show that the error rate of integrity risk allocation is reduced by reallocating the probability of integrity risk under the H0 and H1 hypotheses based on the minimum total error rate criterion, and the actual positioning errors are more tightly enveloped by the protection levels.

Key words: integrity risk, groud-based augmentation system(GBAS), H0 hypothesis, H1 hypothesis, Bayesian decision

CLC Number: 

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