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CN-121500335-B - Ionosphere anomaly monitoring threshold determining method of Beidou satellite-based enhancement system

CN121500335BCN 121500335 BCN121500335 BCN 121500335BCN-121500335-B

Abstract

The invention discloses an ionosphere anomaly monitoring threshold value determining method of a Beidou satellite-based enhancement system, which comprises the steps of obtaining a vertical delay value of an ionosphere puncture point and position information of the vertical delay value; the method comprises the steps of generating an ionosphere data set, obtaining K ionosphere puncture point delay values in a fitting domain around a point to be fitted in the ionosphere data set, calculating at least one monitoring statistic, and determining a monitoring statistic threshold according to a MaxEnt threshold algorithm and the monitoring statistic. According to the ionosphere environment characteristics of the service area of the Beidou satellite-based enhancement system, the ionosphere state is monitored through the ionosphere anomaly monitoring statistics, and the ionosphere anomaly monitoring threshold value is re-analyzed and calculated, so that the service integrity of the Beidou satellite-based enhancement system under the ionosphere anomaly condition can be ensured, and meanwhile, a higher satellite-based enhancement system user service level can be provided under the calm ionosphere condition.

Inventors

  • BAO JUNJIE

Assignees

  • 天津商业大学

Dates

Publication Date
20260508
Application Date
20260114

Claims (10)

  1. 1. The ionosphere anomaly monitoring threshold determination method of the Beidou satellite-based enhancement system is characterized by comprising the following steps of: Obtaining observation data in a target area, preprocessing and resolving the observation data, and obtaining the vertical delay value of the ionosphere puncture point The observation data comprises GNSS original observation data, navigation message data and precise ephemeris data; Vertical delay value of the ionized layer puncture point Storing the position information of the ionosphere data set according to a preset storage path and generating the ionosphere data set; Acquiring K ionosphere puncture point delay values in a fitting domain around a point to be fitted in the ionosphere data set, and calculating at least one monitoring statistic according to the K ionosphere puncture point delay values in the fitting domain around the point to be fitted; and determining a monitoring statistic threshold according to the MaxEnt threshold algorithm and the monitoring statistic.
  2. 2. The ionospheric anomaly monitoring threshold determination method of the beidou satellite-based enhanced system of claim 1, wherein the determining a monitoring statistic threshold according to a MaxEnt threshold algorithm and the monitoring statistic includes: constructing a data set according to the monitoring statistics, and acquiring a discrete probability distribution vector P of the data set; Dividing the data set into two parts of normal monitoring statistics N and abnormal monitoring statistics A according to a pending threshold T * ; Respectively calculating entropy values corresponding to the normal monitoring statistic N and the abnormal monitoring statistic A; Calculating the total entropy value of the normal monitoring statistic N and the abnormal monitoring statistic A according to the Shannon entropy definition ; According to the total entropy value And taking the maximum T * as an optimal threshold, recording the optimal threshold as a final monitoring threshold T, and respectively calculating the final monitoring threshold corresponding to the monitoring statistic according to shannon entropy definition in response to the fact that the number of the monitoring statistic is not one.
  3. 3. The ionospheric anomaly monitoring threshold determination method of the beidou satellite-based enhancement system of claim 2, wherein the expression of the discrete probability distribution vector P is: ; Wherein: Probability of occurrence for the ith magnitude monitoring statistic, L limit as the lower boundary of the monitoring statistic, U limit as the upper boundary of the monitoring statistic, The interval is divided for the interval between the lower boundary and the upper boundary.
  4. 4. The ionospheric anomaly monitoring threshold determination method of the beidou satellite-based enhancement system according to claim 3, wherein the data set is divided into two parts of normal monitoring statistic N and anomaly monitoring statistic a according to a pending threshold T * , and the expression of the normal monitoring statistic N is: ; Wherein: Cumulative probability for normal monitoring statistic N calculated based on pending threshold T * ; The calculation formula of (2) is as follows: 。
  5. 5. The ionospheric anomaly monitoring threshold determination method of the beidou satellite-based enhanced system of claim 4, wherein the anomaly monitoring statistic a has an expression: ; Wherein: cumulative probability for anomaly monitoring statistic a calculated based on pending threshold T * ; The calculation formula of (2) is as follows: 。
  6. 6. the method for determining an ionospheric anomaly monitoring threshold of a beidou satellite-based enhancement system according to claim 4, wherein the data set is divided according to a pending threshold T * , and a value range of the pending threshold T * is as follows: 。
  7. 7. the method for determining an ionospheric anomaly monitoring threshold of a beidou satellite-based enhancement system according to claim 6, wherein the calculating entropy values corresponding to the normal monitoring statistic N and the anomaly monitoring statistic a respectively includes: Entropy of the normal monitoring statistic N The calculation formula of (2) is as follows: ; Entropy of the anomaly monitoring statistic A The calculation formula of (2) is as follows: 。
  8. 8. The ionospheric anomaly monitoring threshold determination method of the Beidou satellite-based augmentation system of claim 7, wherein the total entropy value The calculation formula of (2) is as follows: ; Wherein: for normally monitoring the entropy of the statistic N, The entropy of statistic a is monitored for anomalies.
  9. 9. The ionospheric anomaly monitoring threshold determination method of the Beidou satellite-based augmentation system of claim 2, wherein said determining is based on said total entropy Taking the maximum T * as an optimal threshold, marking the optimal threshold as T, and adopting a calculation formula as follows: 。
  10. 10. The method of claim 1, wherein the preprocessing and resolving the observation data includes sequentially performing cycle slip detection, carrier smoothing pseudo-range, satellite and receiver DCB value estimation and correction on the GNSS raw observation data, and resolving ionospheric delay parameters based on the preprocessed data and navigation messages to obtain an ionospheric puncture point vertical delay value of the target region And its location information.

Description

Ionosphere anomaly monitoring threshold determining method of Beidou satellite-based enhancement system Technical Field The application relates to the field of Beidou satellite navigation, in particular to an ionosphere anomaly monitoring threshold determination method of a Beidou satellite-based enhancement system. Background Aiming at the life safety fields of civil aviation navigation and the like, the star-based enhancement system can meet the system service performance requirements of the navigation flight phase to the vertical guiding precise approach phase in four aspects of precision, integrity, service continuity and availability. As one of the important broadcasting parameters in the single-frequency enhancement service of the star-based enhancement system, whether the ionosphere delay correction and the integrity parameters thereof are accurate or not will seriously affect the service performance of the system. The ionosphere has good space-time correlation in a normal state, but in an abnormal state, the space-time correlation is reduced, and the integrity risk event of the enhancement system is easy to occur. In addition, the latitude of the service area of the Beidou satellite-based enhancement system comprises a middle latitude and a low latitude, and the ionosphere active states of the areas are different. However, in the prior art, the problem of inconsistent regional applicability of key parameters in the ionosphere delay correction and integrity parameter generation technology, especially unreasonable ionosphere anomaly monitoring threshold value setting, causes great reduction of service availability of the Beidou satellite-based enhanced system, and affects the overall service performance of the system. Therefore, the prior art has defects, and the function needs to be improved. Disclosure of Invention In view of the above problems, the present invention aims to provide a method for determining an ionospheric anomaly monitoring threshold of a beidou satellite-based enhanced system, which is used for solving the problem of poor availability of system services caused by the fact that the ionospheric anomaly monitoring threshold in the prior art cannot effectively monitor the active state of an ionospheric in a service area of the beidou satellite-based enhanced system. The invention provides an ionosphere anomaly monitoring threshold determining method of a Beidou satellite-based enhancement system, which comprises the following steps: Obtaining observation data in a target area, preprocessing and resolving the observation data, and obtaining the vertical delay value of the ionosphere puncture point The observation data comprises GNSS original observation data, navigation message data and precise ephemeris data; Vertical delay value of the ionized layer puncture point Storing the position information of the ionosphere data set according to a preset storage path and generating the ionosphere data set; Acquiring K ionosphere puncture point delay values in a fitting domain around a point to be fitted in the ionosphere data set, and calculating at least one monitoring statistic according to the K ionosphere puncture point delay values in the fitting domain around the point to be fitted; and determining a monitoring statistic threshold according to the MaxEnt threshold algorithm and the monitoring statistic. As a preferable technical scheme of the ionosphere anomaly monitoring threshold determination method of the Beidou satellite-based enhancement system, the determining a monitoring statistic threshold according to a MaxEnt threshold algorithm and the monitoring statistic comprises the following steps: constructing a data set according to the monitoring statistics, and acquiring a discrete probability distribution vector P of the data set; Dividing the data set into two parts of normal monitoring statistics N and abnormal monitoring statistics A according to a pending threshold T *; Respectively calculating entropy values corresponding to the normal monitoring statistic N and the abnormal monitoring statistic A; Calculating the total entropy value of the normal monitoring statistic N and the abnormal monitoring statistic A according to the Shannon entropy definition ; According to the total entropy valueAnd taking the maximum T * as an optimal threshold, recording the optimal threshold as a final monitoring threshold T, and respectively calculating the final monitoring threshold corresponding to the monitoring statistic according to shannon entropy definition in response to the fact that the number of the monitoring statistic is not one. As a preferable technical scheme of the ionosphere anomaly monitoring threshold determination method of the Beidou satellite-based enhancement system, the expression of the discrete probability distribution vector P is as follows: ; Wherein: Probability of occurrence for the ith magnitude monitoring statistic, L limit as the lower boundary of the monitoring