CN-122017888-A - Cascade satellite navigation anomaly detection and rejection system and method based on inter-frequency pseudo-range deviation distribution

CN122017888ACN 122017888 ACN122017888 ACN 122017888ACN-122017888-A

Abstract

The invention discloses a cascade satellite navigation anomaly detection and rejection system based on inter-frequency pseudo-range deviation distribution and a method thereof, wherein the cascade satellite navigation anomaly detection and rejection system comprises a positioning residual error detection module and an inter-frequency pseudo-range deviation distribution detection module, and the positioning residual error detection module comprises an anomaly detection module and an anomaly identification module; the inter-frequency pseudo-range deviation distribution detection module is used for judging the abnormality of each pseudo-range and outputting the abnormality detection result of each pseudo-range, the positioning residual error detection module is used for detecting the overall abnormality of the integrity of the satellite navigation system, the abnormality detection module carries out residual error chi-square detection according to the positioning residual error and judges whether the abnormality exists at the moment, and the abnormality identification module constructs an identification subset by means of the result of the inter-frequency pseudo-range deviation distribution detection module so as to realize fault identification and ensure the accuracy of fault identification.

Inventors

XU RUI
ZHANG WEIWEI
YUAN HANWEN
XIONG ZHI
JIA YI

Assignees

南京航空航天大学

Dates

Publication Date: 20260512
Application Date: 20260122

Claims (6)

1. The cascade satellite navigation anomaly detection and rejection system based on inter-frequency pseudo-range deviation distribution is characterized by comprising an inter-frequency pseudo-range deviation distribution detection module and a positioning residual detection module, wherein the positioning residual detection module comprises an anomaly detection module and an anomaly identification module; The inter-frequency pseudo-range deviation distribution detection module is used for judging the abnormality of each pseudo-range of each satellite in the satellite navigation system and outputting the abnormality detection result of each pseudo-range; The positioning residual detection module is used for overall anomaly detection for satellite navigation system integrity, The abnormality detection module carries out residual error chi-square detection according to the positioning residual error and judges whether abnormality exists at the moment; the abnormal recognition module builds a recognition subset by means of the result of the inter-frequency pseudo-range deviation distribution detection module, so that fault recognition is realized, and the accuracy of fault recognition is ensured.
2. The cascaded satellite navigation anomaly detection and rejection system based on inter-frequency pseudorange bias distribution of claim 1, wherein, The input of the inter-frequency pseudo-range deviation distribution detection module is a main frequency point pseudo-range observed quantity set and a sub-frequency point observed quantity set of each satellite in the current epoch, and the output of the inter-frequency pseudo-range deviation distribution detection module is divided into normal pseudo-range observed quantity subsets and abnormal pseudo-range observed quantity subsets; The inter-frequency pseudo-range deviation distribution detection module comprises an inter-frequency pseudo-range difference and distribution detection unit, wherein, The inter-frequency pseudo-range difference unit performs inter-frequency pseudo-range difference processing, namely performing difference processing on double-frequency pseudo-range observed quantity of each satellite in an inter-frequency pseudo-range difference link to obtain inter-frequency pseudo-range deviation of the epoch, wherein the deviation quantity reflects the change characteristics of double-frequency link errors and observed noise, and the detection quantity is subjected to a preset statistical distribution model; The distribution detection unit carries out a standard normal distribution detection algorithm on the detection quantity according to the statistical characteristics of the observation noise of each satellite, and judges whether the corresponding observation is abnormal or not, so that the input pseudo-range observation quantity is divided into a normal subset and an abnormal subset, and a reliable data basis is provided for subsequent abnormal rejection and navigation calculation; The abnormal recognition module is used for carrying out residual error detection on the whole observed quantity set, directly carrying out next positioning calculation if no abnormality is judged, entering the inter-frequency pseudo range deviation distribution detection module for carrying out preliminary classification if abnormality exists, taking a normal subset as a basic subset, circularly adding abnormal observed quantity for carrying out abnormal information detection, removing probability abnormal signals added in the detection once the detection is not passed, otherwise, taking probability abnormal information as normal information, and circularly working until all probability abnormal signals are detected.
3. The method for detecting and rejecting the abnormal satellite navigation based on the inter-frequency pseudo-range deviation distribution is characterized by comprising the following steps: S1, reading out a current epoch main frequency point observation information set from a satellite observation file Wherein, superscript Represent the first A satellite, subscript 1 indicates a main frequency point, Is the first Pseudo-range observed quantity of satellite under main frequency point ; S2, observing information set of main frequency point of current epoch Performing residual error detection, directly outputting all observed quantities to positioning calculation if the residual error detection is passed, and entering step S3 if the residual error detection is not passed; S3, reading the auxiliary frequency point observation information set in the current epoch from the satellite observation file Wherein, the subscript 2 represents a secondary frequency point, Is the first Pseudo-range observed quantity under satellite auxiliary frequency point and main frequency point observed information set of current epoch And a set of secondary frequency point observation information in the current epoch Performing inter-frequency pseudo-range difference on the observed quantity in the obtained , Is the first Pseudo-range observed quantity under main frequency point and auxiliary frequency point of satellite And Is a difference of (2); s4, pair Each inspection amount in the data is subjected to a standard normal distribution detection algorithm, and the corresponding pseudo-range observed quantity with a normal detection result is divided into a constellation corresponding normal observed quantity set Otherwise, the constellation corresponding abnormal observed quantity set is divided ; S5, judging whether the number of the constellation observables of the basic intact subset at the moment meets the requirement: , , Wherein: And Step S6 is executed if the requirement is met, if the requirement is not met, the abnormal information detection method based on the least square residual error is returned; S6, merging And Obtaining Merging And Obtaining Will (i) be The set is taken as a basic subset, and is matched with Performing residual detection, ensuring the integrity of the subset again, if the detection is passed, entering a step S7, otherwise, returning to an abnormal information detection method based on least square residual; S7, slave Selecting one pseudo-range observed quantity in sequence in a concentrated manner to carry out residual error detection, and if the pseudo-range observed quantity passes the detection, dividing the observed quantity into A set, eliminating the observed quantity if the set does not pass the detection; looping through steps S7 to The sets are subjected to residual error detection and output to the final And (5) integrating to position resolving and finishing identification.
4. The method for detecting and eliminating abnormal satellite navigation according to claim 3, wherein in step S3, the inter-frequency pseudo-range difference: for the same satellite Pseudo-range observed quantity under main frequency point and auxiliary frequency point And The difference is calculated as follows: (1) Wherein, the upper mark is Represent the first The satellite, subscript 1, represents the primary frequency point and subscript 2 represents the secondary frequency point.
5. The method for detecting and eliminating abnormal satellite navigation based on inter-frequency pseudo-range deviation distribution according to claim 4, wherein in step S4, a standard normal distribution detection algorithm: For the first Satellites, detection amount under the epoch Assuming no anomalies, compliance with expectations is Variance is Normal distribution of (2) The method comprises the following steps: (2) Constructing normalized statistics The following is shown: (3) Wherein, the , I is the number of stationary observation samples, i is the ith stationary observation sample, and at the false alarm rate is When the corresponding double-side detection threshold is : (4) Wherein, the Probability density function of standard normal distribution; The decision criteria for the algorithm are expressed as: (5)。
6. The method for detecting and eliminating abnormal satellite navigation based on inter-frequency pseudo-range deviation distribution according to claim 5, wherein in the step S5, the method for detecting abnormal information based on least square residual error comprises the following steps: abnormal information detection based on least square residual errors is generally carried out by adopting pseudo-range residual errors, and a pseudo-range observed quantity equation is as follows: (6) x is the three-dimensional position variation and the receiver clock error, y is the pseudo-range observed quantity of the current n visible satellites, namely pseudo-range observed values, H is an n multiplied by 4 coefficient matrix, and epsilon is pseudo-range observed noise; Based on least square method, obtaining least square solution of state quantity : (7) Wherein T is the transpose operation of the matrix; deviation vector of available observables : (8) Least squares residual vector w: ε(9) Constructing a residual square sum SSE: (10) the following probability equation is given for the false alarm rate: (11) Wherein, the For the probability of a certain random event occurring, For the pseudorange observation noise variance, Is of degree of freedom of Is a chi-square distribution density function of (c), Representing the number of currently visible stars; to set false alarm rate, according to the formula The values, for classical RAIM algorithms, will construct a uniform detection volume At this time threshold The method comprises the following steps: (12) when the detected quantity V is between the thresholds, the observed quantity is considered to be consistent at the moment, otherwise, the observed quantity is considered to be abnormal; and when the abnormality is detected, circularly eliminating the observed quantity until an observed quantity set lower than an observation threshold is found, wherein the set is a reliable observed quantity.

Description

Cascade satellite navigation anomaly detection and rejection system and method based on inter-frequency pseudo-range deviation distribution Technical Field The invention belongs to the technical field of satellite navigation system integrity detection, and particularly relates to a cascade satellite navigation anomaly detection and rejection system and a cascade satellite navigation anomaly detection and rejection method based on inter-frequency pseudo-range deviation distribution. Background The global satellite navigation system (Global Navigation SATELLITE SYSTEM, GNSS) has the advantage of providing absolute positioning services for global users all over the day, all around the clock. However, for satellite navigation subsystems, the satellite navigation signals are distorted somewhat from the time they are generated and propagated to the user for reception, due to satellite anomalies and environmental and receiver effects. The satellite navigation system can determine whether to enter a practical stage of navigation positioning only when certain performance requirements are met, and the performance requirements mainly comprise accuracy, integrity, continuity, availability and the like. Of these, integrity is the most critical performance requirement. For satellite navigation positioning systems, the level of integrity performance determines the safety and reliability of the navigation positioning service. In order to solve the problem, monitoring means are required to perform monitoring and rejection, so that users are free from catastrophic information misguidance caused by satellite signal abnormality or deformation. The integrity monitoring performance mainly detects and identifies satellite faults, and in the fault detection process of the satellite navigation system, the most important is monitoring at the user side. The monitoring of the user side, namely the autonomous integrity monitoring (RAIM) technology of the receiver, refers to that the receiver acquires various useful information through real-time signal processing by utilizing the received satellite signals, and performs consistency check by means of redundancy observance. When the positioning error exceeds a preset detection threshold, the technology can give an alarm to the user in time, so that the safety of navigation service is ensured. In an ideal state, the autonomous integrity monitoring of the receiver can realize detection, isolation and rejection of fault measurement sources in the navigation resolving process so as to ensure the effectiveness and reliability of positioning results. For the case of single observance quantity disturbance, the method generally has higher identification accuracy. However, in practical applications, anomalies may occur in multiple observables at a certain frequency point at the same time, so that the difficulty of accurately identifying anomalies increases significantly. It is noted that current receivers are generally capable of receiving signals at multiple frequencies, and that observations of the same satellite at different frequencies should be kept consistent under normal conditions. Based on the characteristics, a new anomaly identification method can be explored from the perspective of consistency of the pseudo-range observed quantity among the frequency points, so that the accuracy of anomaly identification is improved. Therefore, the invention provides a cascade satellite navigation anomaly detection and elimination system and a cascade satellite navigation anomaly detection and elimination method based on inter-frequency pseudo-range deviation distribution. The method mainly uses residual error detection, and fusion judgment is carried out on the observed quantity of the receiver by means of pseudo-range inter-frequency deviation consistency detection, so that the accuracy of satellite navigation anomaly detection is effectively improved, the reliability and integrity of the system are enhanced, and the method has important engineering application value. Disclosure of Invention The invention provides a cascade satellite navigation anomaly detection and elimination system and a cascade satellite navigation anomaly detection and elimination method based on inter-frequency pseudo-range deviation distribution, which are used for solving the problems in the prior art. In order to achieve the above purpose, the invention adopts the following technical scheme: The cascade satellite navigation anomaly detection and rejection system based on inter-frequency pseudo-range deviation distribution comprises an inter-frequency pseudo-range deviation distribution detection module and a positioning residual detection module, wherein the positioning residual detection module comprises an anomaly detection module and an anomaly identification module; The inter-frequency pseudo-range deviation distribution detection module is used for judging the abnormality of each pseudo-range of each satellite in the sa