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CN-121995402-A - GPS/GLONASS inter-frequency clock bias modeling and forecasting method and device

CN121995402ACN 121995402 ACN121995402 ACN 121995402ACN-121995402-A

Abstract

The invention discloses a GPS/GLONASS frequency clock bias modeling and forecasting method and device, the method comprises the steps of obtaining positioning data received by a receiver from a satellite, constructing a geometrical ionosphere-free phase combination observation value according to the positioning data, removing ambiguity constants of the geometrical ionosphere-free phase combination, which absorb invariants when phase hardware delays are absorbed, by adopting an inter-epoch difference method to obtain a single station ionosphere-free combination IFCB, integrating multi-station observation data, calculating final IFCB bias in a multi-station weighted average mode, carrying out harmonic analysis according to the IFCB data, obtaining an accurate period of IFCB sequences by adopting fast Fourier transformation, providing a IFCB model based on a third-order polynomial and 7-period harmonic function, carrying out experimental forecasting according to a IFCB time sequence model, extracting periodic characteristics of IFCB bias, and calculating an optimal forecasting period. The method can correct the GPS/GLONASS system observation data in real time, and further execute accurate correction on the positioning result so as to improve the positioning accuracy.

Inventors

  • ZHANG FAN
  • YAN WENJIE
  • SHEN JIALEI

Assignees

  • 中国人民解放军陆军工程大学

Dates

Publication Date
20260508
Application Date
20241101

Claims (10)

  1. 1. A method for modeling and forecasting clock bias between GPS/GLONASS frequencies, comprising: Acquiring positioning data of satellites through a receiver, wherein the positioning data comprise three-frequency carriers and pseudo-range observation values of the satellites of the GPS/GLONASS system; Constructing phase hardware delay of a satellite end and a receiver end according to the positioning data, and dividing the phase hardware delay into two parts, namely time-varying and time-invariant; Constructing a geometry-free ionosphere-free GFIF combination from the known data, determining a geometry-free ionosphere-free GFIF combination and a variance, wherein the geometry-free ionosphere-free GFIF combination comprises an ionosphere-free combination IFCB and an ambiguity constant that is invariant when phase hardware delays are absorbed; removing invariant ambiguity constants in the geometric ionosphere-free GFIF combination, which absorb phase hardware delay, by adopting an epoch-to-epoch difference method to obtain a single station ionosphere-free combination IFCB and variance; Estimating a satellite ionosphere-free layer IFCB by adopting a multi-station weighted average mode according to multi-station observation data, obtaining a satellite ionosphere-free combination IFCB by adopting an accumulation mode, and converting the ionosphere-free combination IFCB into a non-difference non-combination IFCB correction by adopting a correction relation; According to IFCB deviation data, adopting fast Fourier transformation to make harmonic analysis to obtain accurate period of IFCB sequence, providing IFCB deviation model based on third-order polynomial and 7-period harmonic function, according to IFCB time sequence model making experiment forecast, extracting and comparing IFCB deviation periodic characteristics and calculating optimum forecast period.
  2. 2. The method for modeling and forecasting clock bias between GPS/GLONASS frequencies of claim 1, wherein said obtaining positioning data of satellites by a receiver comprises: ; Wherein, the And Respectively representing three-frequency carrier and pseudo-range observation values, and superscript And Respectively representing satellite PRN number and GNSS system, subscript And Representing the receiver and frequency, i=1, 2, Representing the distance between the measurement site and the satellite, And For receiver clock correction and satellite clock correction, In order to achieve the light velocity, the light beam is, And Respectively zenith tropospheric wet delay and its projection function, Representing the factor of the ionospheric coefficients, For the frequency of the system, As an ionospheric parameter at a first frequency, And Respectively the wavelength and the integer ambiguity, And Representing receiver side and satellite side phase hardware delays, And Pseudo-range hardware delays at the receiver end and the satellite end respectively; for the GLONASS system, when i=1 or 2, When i=3, and when i=3, 。
  3. 3. The method for modeling and forecasting clock bias between GPS/GLONASS frequencies as defined in claim 2, wherein constructing satellite-side and receiver-side phase hardware delays based on said positioning data, dividing said phase hardware delays into two parts, time-varying and time-invariant, comprises: ; Wherein, the And The phase hardware delays at the satellite end and the receiver end respectively, And Time-varying parts of the phase hardware delays at the satellite side and the receiver side respectively, And The time-invariant parts of the phase hardware delay of the satellite end and the receiver end are respectively.
  4. 4. A method for modeling and forecasting clock bias between GPS/GLONASS frequencies as claimed in claim 3, wherein said constructing a geometry-free ionosphere-free GFIF combination from known data determines a geometry-free ionosphere-free GFIF combination and variance as follows: ; ; , , ; Wherein, the Representing a no geometry no ionosphere GFIF combination, Representing the geometric free ionosphere GFIF combined variance, For satellite clock differences calculated from the L1/L2 ionosphere-free combination, For satellite clock differences calculated from the L1/L3 ionosphere-free combination, Indicating that the ionosphere-free combination IFCB, To absorb the invariant ambiguity constant for phase hardware delay, 、 And Respectively representing the integer ambiguities of three frequencies, 、 The frequency is represented by a frequency value, For a third frequency bin receiver phase hardware delay, , And All were set to 0.02 weeks.
  5. 5. The method for modeling and forecasting GPS/GLONASS inter-frequency clock bias as claimed in claim 4, wherein said using inter-epoch difference method removes ambiguity constants of the non-geometric non-ionosphere GFIF combinations that absorb phase hardware delay invariant to obtain single station non-ionosphere combinations IFCB and variances as follows: ; Wherein, the The ionosphere-free combination IFCB based on the epoch-to-epoch differential representation, And Respectively represent Calendar element The combined observables of the non-geometry and non-ionosphere composed of epoch L1, L2 and L3 frequencies, Is that Is a function of the variance of (a), Representing the number of epochs; And setting a triple standard deviation detection threshold in the execution process of the inter-epoch difference method.
  6. 6. The method for modeling and forecasting GPS/GLONASS inter-frequency clock bias as defined in claim 5, wherein estimating satellite ionosphere-free layers IFCB based on multi-station observations using multi-station weighted averaging, obtaining satellite ionosphere-free combinations IFCB by accumulation, and converting ionosphere-free combinations IFCB to non-differential non-combination IFCB corrections by correction relationships, comprises: the satellite ionosphere IFCB is estimated by multi-station weighted averaging as follows: ; Wherein, the Indicating that the satellites are free of an ionosphere IFCB, Representing the satellite altitude-related weights, Then the satellite altitude angle is the one that is the satellite altitude angle, Representing the number of measuring stations; obtaining epoch by accumulating Time satellite Ionosphere-free combination IFCB of (a) is as follows: ; Wherein, the Representing calendar elements Time satellite Is provided with an ionosphere-free combination IFCB, Representing reference time epochs Time satellite Is free of ionosphere combinations IFCB; The conversion of ionosphere-free combination IFCB to non-differential non-combination IFCB correction is as follows: ; Wherein, the Representing the non-difference non-combination IFCB correction.
  7. 7. The method for modeling and forecasting clock bias between GPS/GLONASS frequencies as claimed in claim 6, wherein, Setting up to discard the satellite observation arc section when the satellite observation arc section is smaller than 10 min; setting a satellite cut-off height angle to be 10; if the ionosphere-free combinations IFCB of the same satellite at different stations have the same altitude angle, the same weight is given.
  8. 8. The method for modeling and forecasting clock bias between GPS/GLONASS frequencies as defined in claim 7, wherein harmonic analysis is performed by fast Fourier transform according to IFCB bias data to obtain the precise period of IFCB sequence, and IFCB bias model based on third-order polynomials and 7-period harmonic function is proposed as follows: ; in the formula, Representation of The IFCB deviations of the epoch, The term of the constant is represented by a term, 、 And First order, second order and third order term coefficients respectively, In order for the amplitude to be the same, In order to be able to carry out a cycle, The phase is represented by a phase value, Representing the order of the harmonic function; and carrying out experimental forecasting according to the IFCB deviation model, extracting and comparing the periodic characteristics of IFCB deviation, and calculating the optimal forecasting period.
  9. 9. A GPS/GLONASS inter-frequency clock bias modeling and forecasting device, for implementing the GPS/GLONASS inter-frequency clock bias modeling and forecasting method according to any one of claims 1 to 8, the device comprising: the acquisition module is used for acquiring positioning data of satellites through the receiver, wherein the positioning data comprise three-frequency carriers and pseudo-range observation values of the GPS/GLONASS system satellites; The first determining module is used for constructing phase hardware delay of a satellite end and a receiver end according to the positioning data and dividing the phase hardware delay into two parts, namely time-varying and time-invariant; A second determining module, configured to construct a geometry-free ionosphere-free GFIF combination from the known data, and determine a geometry-free ionosphere-free GFIF combination and a variance, wherein the geometry-free ionosphere-free GFIF combination includes an ionosphere-free combination IFCB and an ambiguity constant that is invariant when phase hardware delays are absorbed; The third determining module is configured to remove an ambiguity constant that is in the combination without geometry and ionosphere GFIF and that is invariant when the phase hardware delay is absorbed by using an epoch-to-epoch difference method, so as to obtain a combination IFCB without ionosphere for a single station and a variance; A fourth determining module, configured to estimate a satellite ionosphere-free layer IFCB according to the multi-station observation data by using a multi-station weighted average method, obtain a satellite ionosphere-free combination IFCB by using an accumulation method, and convert the ionosphere-free combination IFCB into a non-differential non-combination IFCB correction by using a correction relation; And a fifth determining module, configured to perform harmonic analysis by using fast fourier transform according to IFCB deviation data, obtain an accurate period of IFCB sequence, propose a IFCB deviation model based on a third-order polynomial and a 7-period harmonic function, perform experimental prediction according to IFCB time sequence model, extract and compare periodic features of IFCB deviation, and calculate an optimal prediction period.
  10. 10. A computer readable storage medium storing one or more programs, wherein the one or more programs comprise instructions, which when executed by a computing device, cause the computing device to perform any of the methods of claims 1-8.

Description

GPS/GLONASS inter-frequency clock bias modeling and forecasting method and device Technical Field The invention relates to the technical field of satellite positioning, in particular to a GPS/GLONASS inter-frequency clock bias modeling and forecasting method and device. Background Real-time three-frequency precise single point positioning (Precise point positioning, PPP) or PPP-RTK (Precise Point Positioning-Real-TIME KINEMATIC) requires Real-time estimation of precise satellite orbit and clock bias products and Inter-frequency clock bias (Inter-frequency clock bias, IFCB) corrections, resulting in a substantial increase in workload and affecting Real-time data stream transmission efficiency. If a high-precision IFCB forecast model can be established to realize high-precision modeling forecast of IFCB deviation, the real-time PPP calculation efficiency can be effectively improved, and the data preparation workload is reduced. Currently, global satellite navigation system (Global navigation SATELLITE SYSTEM, GNSS) satellite precision clock correction products published by the International GNSS service organization (International GNSS SERVICE, IGS) are calculated based on ionospheric-free combinations of specific frequencies, for example, the Global Positioning System (GPS) uses an L12 frequency ionospheric-free combination, and if the satellite clock correction product is used to correct satellite clock correction of a third frequency, the problem of clock deviation between frequencies is caused. Because IFCB exists, the IGS satellite clock-difference product cannot be directly applied to the multi-frequency PPP, and the IFCB processing is a key problem which needs to be solved in the multi-frequency PPP. However, a high-precision IFCB deviation model of the GLONASS system has not been established at present, and the IFCB modeling method for the GPS system satellite has defects, and the modeling precision needs to be further improved. Disclosure of Invention The invention aims to provide a GPS/GLONASS inter-frequency clock bias modeling and forecasting method and device, which are used for solving the problems of insufficient modeling precision and low positioning precision of GPS and GLONASS system satellites IFCB bias. The technical scheme adopted for solving the technical problems is as follows: In a first aspect, the present invention provides a method for modeling and forecasting clock bias between GPS/GLONASS frequencies, including: Acquiring positioning data of satellites through a receiver, wherein the positioning data comprise three-frequency carriers and pseudo-range observation values of the satellites of the GPS/GLONASS system; Constructing phase hardware delay of a satellite end and a receiver end according to the positioning data, and dividing the phase hardware delay into two parts, namely time-varying and time-invariant; Constructing a geometry-free ionosphere-free GFIF combination from the known data, determining a geometry-free ionosphere-free GFIF combination and a variance, wherein the geometry-free ionosphere-free GFIF combination comprises an ionosphere-free combination IFCB and an ambiguity constant that is invariant when phase hardware delays are absorbed; removing invariant ambiguity constants in the geometric ionosphere-free GFIF combination, which absorb phase hardware delay, by adopting an epoch-to-epoch difference method to obtain a single station ionosphere-free combination IFCB and variance; Estimating a satellite ionosphere-free layer IFCB by adopting a multi-station weighted average mode according to multi-station observation data, obtaining a satellite ionosphere-free combination IFCB by adopting an accumulation mode, and converting the ionosphere-free combination IFCB into a non-difference non-combination IFCB correction by adopting a correction relation; According to IFCB deviation data, adopting fast Fourier transformation to make harmonic analysis to obtain accurate period of IFCB sequence, providing IFCB deviation model based on third-order polynomial and 7-period harmonic function, according to IFCB time sequence model making experiment forecast, extracting and comparing IFCB deviation periodic characteristics and calculating optimum forecast period. Preferably, the acquiring, by the receiver, positioning data of the satellite includes: ; Wherein, the AndRespectively representing three-frequency carrier and pseudo-range observation values, and superscriptAndRespectively representing satellite PRN number and GNSS system, subscriptAndRepresenting the receiver and frequency, i=1, 2,Representing the distance between the measurement site and the satellite,AndFor receiver clock correction and satellite clock correction,In order to achieve the light velocity, the light beam is,AndRespectively zenith tropospheric wet delay and its projection function,Representing the factor of the ionospheric coefficients,For the frequency of the system,As an ionospheric parameter at a first