GBAS Integrity Risk Allocation Using Key Satellite Segmentation
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Solution Overview
Problem
The existing GBAS integrity risk allocation method fails to accurately reflect real error values due to redundancy in calculated protection levels, leading to decreased system availability.
Innovation Solution
A GBAS integrity risk allocation system based on key satellites, which determines key satellites, pairs, and groups by comparing vertical protection levels with alarm limits, and allocates integrity risks using fault probabilities to reduce redundancy and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the existing GBAS integrity risk allocation method is used, then the protection level can be calculated, but the calculated protection level contains redundancy that does not accurately reflect real error values, leading to decreased system availability
Solution Approach 1:
The patent segments the satellite constellation into key satellites and non-key satellites based on their geometric relationships with the receiver. This segmentation allows differential integrity risk allocation: key satellites use H2 hypothesis with fault probability-based risk allocation, while non-key satellites use H0/H1 hypotheses with protection level-based risk allocation. This segmented approach eliminates the redundancy in the existing uniform method and accurately reflects the actual error contributions from different satellites, thereby improving measurement precision without compromising system availability.
2Loss of information
If the existing integrity risk allocation method is used, then the risk values can be allocated to subsystems, but the allocation does not accurately reflect real error values due to redundancy in protection level calculations
Solution Approach 1:
The patent applies local quality by differentiating the integrity risk allocation approach for different satellites based on their local geometric characteristics. Key satellites (those with significant geometric impact) receive H2 hypothesis allocation with fault probability, while non-key satellites receive H0/H1 hypothesis allocation with protection level methods. This localized differentiation ensures that the risk allocation accurately reflects the actual error contribution of each satellite group, eliminating information loss without requiring complete redesign of the entire allocation system.
Data Source
AI summary
A GBAS integrity risk allocation system based on key satellites is used to perform a GBAS integrity risk allocation method, including: reading data from an ephemeris at a certain time, and determining numbers of key satellites, key satellite pairs and key satellite groups at a certain time; under H2 hypothesis, allocating the integrity risks by using the fault probability of satellites in key satellite pairs or key satellite groups, where the integrity risks allocated by using the fault probability of satellites in key satellite pairs or key satellite groups include integrity risks caused by dual-receiver fault and integrity risks caused by ranging source fault; under H0 and H1 hypotheses, allocating the integrity risks by using the fault probability of non-key satellites; making an integrity allocation table according to the integrity risk allocation under the H0, H1 and H2 hypotheses.