Establishment method of threshold model for integrity risk monitoring of Beidou ground-based augmentation system

Abstract

The present invention provides a method for establishing a threshold model for the integrity risk monitoring of the Beidou ground-based augmentation system, including the following steps: a) identifying the satellite number, and inputting all the monitoring statistics data of a satellite period; b) converting all the monitoring statistics data entered by The initial isometric measurement is uniformly converted into a proportional measurement; c) Calculate the correlation coefficient between the monitoring statistics and determine the degrees of freedom and weight coefficients required for hypothesis testing; d) Calculate the observed value of the chi-square test statistic; e) Judging whether the observed value of the chi-square test statistic is in the rejection domain; f) Calculating the risk rate; g) Calculating the reliability value; h) Using the inverse transformation of the unified measurement to obtain the threshold model. The invention obtains an effective integrity risk monitoring threshold model for the Beidou ground-based augmentation system from the collected monitoring data, which can effectively reduce the probability of missing alarms and false alarms in the process of integrity monitoring.

Description

technical field [0001] The invention relates to the technical field of satellite navigation, in particular to a method for establishing a threshold model for integrity risk monitoring of a Beidou ground-based augmentation system. Background technique [0002] GBAS (ground-based augmentation systems) is an enhancement technology that uses differential technology to improve the positioning accuracy of satellite navigation systems within a local area (generally within 150km). The basic principle is to calculate the pseudorange correction number through the ground reference station with known and determined position, and then broadcast the correction number to the user, so that the airborne user can correct the received satellite positioning signal, thereby improving the positioning accuracy. Through the pseudo-range local difference, the accuracy of 1-5m can be obtained. If the carrier phase local difference technique is used, even centimeter-level results can be obtained. Th...

AI Technical Summary

Problems solved by technology

However, with the continuous development and improvement of GBAS approach service types, in order to cover all possible risks as much as possible, more and more monitoring statistics have appeared, and the forms of monitoring quantities have become more and more complex

If these statistics are processed separately according to the existing method and the threshold model is established without considering the correlation between these statistics, two possible problems may occur. One is missing alarms, that is, when establishing a single monitoring statistic The threshold model does not consider other statistics at the same time, resulting in insufficient information used, making the established threshold model too large, missing the integrity risk that needs to be considered, resulting in the occurrence of integrity risk; the second is false alarms, that is, two Surveillance statistics may be correlated, and double counting in the calculation of integrity risk may cause the calculated integrity risk to be too large to reflect the actual situation

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