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CN-120742364-B - Global ionosphere TEC inversion method based on Galileo HAS service

CN120742364BCN 120742364 BCN120742364 BCN 120742364BCN-120742364-B

Abstract

The invention relates to a global ionosphere TEC inversion method based on Galileo HAS service, which comprises the steps of obtaining correction information through HAS service, preprocessing observation data of a reference station according to the correction information, obtaining a preprocessed carrier phase observation value, calculating carrier phase ambiguity and a purified carrier phase observation value according to the preprocessed carrier phase observation value, calculating total electron content STEC of an inclined path according to the carrier phase ambiguity and the purified carrier phase observation value, constructing a double-layer ionosphere network model according to geographic coordinates and STEC of ionosphere puncture points, inverting the vertical total electron content of an ionosphere by utilizing Kalman filtering, and obtaining and compressing the vertical total electron content of the ionosphere. The invention breaks through the network dependence of the traditional foundation enhancement, and can still provide continuous and reliable ionosphere delay correction under the scenes of ocean, desert and the like.

Inventors

  • TANG JUN
  • SUN YUE
  • Teng Hanyang
  • DING MINGFEI
  • WANG JINTAO

Assignees

  • 昆明理工大学

Dates

Publication Date
20260508
Application Date
20250716

Claims (6)

  1. 1. A global ionosphere TEC inversion method based on Galileo HAS services, comprising: acquiring correction information through HAS service, preprocessing observation data of a reference station according to the correction information, and acquiring a preprocessed carrier phase observation value, wherein the method comprises the following steps: calculating a track correction and a clock correction at the current moment according to the correction information; calculating real-time precision clock correction according to the clock correction; preprocessing the observed data of the reference station according to the track correction and the real-time precision clock difference: ; Wherein, the As a pre-processed carrier phase observation, As an observation of the phase of the carrier, As a function of the carrier frequency, For real-time precision clock correction after HAS correction, In order to achieve the light velocity, the light beam is, For the track correction under ECEF, Unit vectors for satellite to receiver; Calculating carrier phase ambiguity and a cleaned carrier phase observation from the preprocessed carrier phase observation, comprising: calculating a double-difference observed value and an ionosphere free combination observed value according to the preprocessed carrier phase observed value; Respectively acquiring fixed wide-lane ambiguity and floating ambiguity by using the double-difference observed value and the ionosphere free combination observed value; calculating geometric free ambiguity according to the fixed wide-lane ambiguity and the floating ambiguity, and resolving to obtain carrier phase ambiguity and a purified carrier phase observation value; Calculating the double difference observations includes: ; Wherein, the Is the value of the observation of the double difference, For the wide lane ambiguity of the lane, 、 Representing two frequency band carrier phase observations that have been corrected by the track and clock correction of the HAS; 、 Respectively, stands for inter-station and inter-satellite differences, A, B stands for two different receivers or satellites, 、 Carrier frequencies of two different frequency bands of the Galileo satellite navigation system are respectively; Calculating the total electronic content STEC of an ionized layer of the inclined path according to the carrier phase ambiguity and the purified carrier phase observed value; Constructing a double-layer ionosphere network model according to the geographic coordinates of the ionosphere puncture points and the total electronic content STEC of the inclined path ionosphere; And inverting the vertical total electron content of the ionized layer by utilizing Kalman filtering according to the double-layer ionized layer network model, obtaining the vertical total electron content of the ionized layer and compressing the vertical total electron content of the ionized layer.
  2. 2. The global ionosphere TEC inversion method based on Galileo HAS service according to claim 1, wherein constructing a dual-layer ionosphere network model comprises: Processing the total electron content STEC of the ionized layer of the inclined path, calculating the spatial gradient of the STEC of the region, layering the ionized layer according to the spatial gradient of the STEC of the region, and dividing the network resolution; Establishing a linear relation between STEC and the vertical total electron content of the grid point where the corresponding ionosphere puncture point is located according to the geographic coordinates of the ionosphere puncture point and STEC; And filling the vertical total electron content to the corresponding grid points as an initial value according to the linear relation, and constructing the double-layer ionosphere network model.
  3. 3. The global ionosphere TEC inversion method based on Galileo HAS service according to claim 2, wherein calculating regional STEC spatial gradients comprises: ; Wherein, the For the spatial gradient of the region STEC, In order to correct the magnetic weft thread, When it is local.
  4. 4. The global ionosphere TEC inversion method based on Galileo HAS services according to claim 1, wherein inverting the ionosphere vertical total electron content according to kalman filtering comprises: s1, constructing an initialization state vector according to VTEC in the double-layer ionosphere network model; s2, carrying out time updating, and predicting a priori state vector and a priori covariance matrix at the current moment; S3, constructing an observation equation according to the prior state vector and the prior covariance matrix at the current moment and combining the STEC observation value, and calculating Kalman gain; s4, updating the state estimation and the posterior covariance matrix according to the Kalman gain, outputting an inverted real-time VTEC value, and adding one time to return to S2.
  5. 5. The global ionosphere TEC inversion method based on Galileo HAS service according to claim 1, wherein before obtaining the ionosphere vertical total electron content for compression, extracting the VTEC error standard deviation of each grid point from the covariance matrix of the kalman filter, and performing error evaluation on the inversion result.
  6. 6. The global ionosphere TEC inversion method based on Galileo HAS services according to claim 1, wherein obtaining ionosphere vertical total electron content for compression comprises: Wherein, the For the total message length to be the same, For the length of the compressed underlying grid data, For the top-level mesh data length, For GIVEI data lengths, B is the number of bytes that can be accommodated per page of text.

Description

Global ionosphere TEC inversion method based on Galileo HAS service Technical Field The invention relates to the technical field of satellite navigation enhancement, in particular to a global ionosphere TEC inversion method based on Galileo HAS service. Background Ionospheric delay is one of the main sources of error for high-precision applications of global satellite navigation systems (Global Navigation SATELLITE SYSTEM, GNSS), whose time-space variation characteristics make real-time accurate corrections a technical difficulty. Traditional ionosphere total electron content (Total Electronic Content, TEC) inversion methods are highly dependent on Ground-based augmentation system (group-Based Augmentation Systems, GBAS) or post-internet acquired precise ephemeris data, but in non-network coverage areas such as polar regions, oceans and the like or in emergency scenes such as communication interruption caused by disasters and the like, the prior art is difficult to meet the requirements of real-time, global and robustness. In recent years, the push of the Galileo system high-precision service (High Accuracy Service, HAS) provides a new idea for global real-time ionosphere monitoring. HAS directly broadcasts the precise orbit and clock correction of GPS/Galileo satellite through E6-B signal, and can get rid of the dependence on ground communication network theoretically. At present, research focuses on performance verification of HAS in the field of precise positioning, and the existing ionosphere modeling method faces two major technical bottlenecks, namely, firstly, the error of a regional ionosphere model is obviously increased in the period of low latitude or magnetic storm, the predicted deviation of TEC in an equatorial region can reach more than 20TECU (Total Electron Content Unit,1 TECU=10 16electrons/m2), and secondly, the global ionosphere grid HAS wide coverage range but HAS the problems of insufficient space-time resolution and poor timeliness. Although the international GNSS service provides high frequency TEC data through real-time services, it still relies on internet transmission to be unable to service a communication limited scenario. The HAS service core technical architecture relies on a high-stability space section and a high-precision ground section of the Galileo system. The space section adopts (Medium Earth Orbit, MEO) satellites with E6 frequency band broadcasting capability to construct a global enhanced signal broadcasting platform, the ground section forms a closed-loop system by a multi-frequency multi-mode monitoring station, a high-precision atomic clock and a data processing center, high-precision corrections such as satellite precision orbit and clock correction are generated in real time by utilizing multi-frequency observation data in combination with a Kalman filtering algorithm, and the reliable transmission is ensured by low-delay broadcasting of an E6-B channel and assistance of a data guarantee mechanism. Galileo HAS HAS wide application prospect in the fields of unmanned aerial vehicle navigation, surveying and mapping geography, disaster monitoring and the like by virtue of high-precision track and clock correction capability. The current ionosphere delay correction method mainly depends on a foundation enhanced network or post-hoc ephemeris, and is difficult to cover non-network areas such as oceans, deserts and the like. In addition, the space-time resolution of the global ionosphere model is insufficient, the dynamic change of the ionosphere cannot be adapted in real time, and particularly under complex disturbance such as magnetic storm or equatorial abnormality, the error is obviously increased, so that the high-precision positioning stability is reduced. The existing Galileo HAS service provides precise correction of a star base, but lacks real-time self-adaptive modeling capability for ionosphere disturbance, so that the application of the Galileo HAS service in dynamic scenes such as unmanned aerial vehicle navigation and automatic driving is limited. Disclosure of Invention The invention aims to provide a global ionosphere TEC inversion method based on Galileo HAS service, which breaks through the traditional foundation-enhanced network dependence, can still provide continuous and reliable ionosphere delay correction in the scenes of ocean, desert and the like, and provides technical support for high-precision applications such as unmanned aerial vehicle navigation, automatic driving and the like. In order to achieve the above object, the present invention provides the following solutions: a global ionosphere TEC inversion method based on Galileo HAS services, comprising: acquiring correction information through HAS service, preprocessing the observation data of a reference station according to the correction information, and acquiring a preprocessed carrier phase observation value; Calculating carrier phase ambiguity and a purified carrier phase observatio