CN-122017913-A - Full-system PPP-RTK positioning method considering ambiguity-like code deviation

CN122017913ACN 122017913 ACN122017913 ACN 122017913ACN-122017913-A

Abstract

A full-system PPP-RTK positioning method considering ambiguity-like code deviation comprises the following steps of firstly establishing a multi-constellation multi-frequency point GNSS code observation and carrier phase observation model, then uniformly introducing ambiguity-like code deviation ALCB parameters into the code observation model to obtain a GNSS original observation equation containing ambiguity-like code deviation ALCB, carrying out targeted processing on eight classes of rank deficiency of the GNSS original observation equation of ambiguity-like code deviation ALCB, judging whether single-station difference ALCB between a user and a reference station is obvious or not according to a full-rank PPP-RTK network model and a traditional PPP-RTK network model to obtain two classes of user end models, transmitting double-difference ambiguity parameters in a filtering calculation flow of the two classes of user end models to obtain two classes of user end models with fixed ambiguity, correspondingly selecting the two classes of user end models with fixed ambiguity according to network scene requirements of actual GNSS observation, and then carrying out PPP-RTK real-time positioning calculation to obtain a positioning result. The invention considers ALCB influence and improves the positioning precision.

Inventors

ZHANG BAOCHENG
Che Dehe
HOU PENGYU
CHAI YANJU

Assignees

中国科学院精密测量科学与技术创新研究院

Dates

Publication Date: 20260512
Application Date: 20260413

Claims (10)

1. The full-system PPP-RTK positioning method considering the ambiguity-like code deviation is characterized by comprising the following steps of: Firstly, establishing a multi-constellation multi-frequency point GNSS code observation and carrier phase observation model based on a CDMA and FDMA system, and then uniformly introducing ambiguity-like code bias ALCB parameters into the code observation model so as to obtain a GNSS original observation equation containing the ambiguity-like code bias ALCB; The second step, the eight kinds of rank deficiency of the GNSS original observation equation containing the ambiguity-like code bias ALCB is processed, wherein the rank deficiency between satellite code bias and ALCB is eliminated by taking ALCB of the first receiver as a reference reforming parameter, the first epoch receiver clock bias is selected as a reference, the receiver phase bias is transmitted in the filtering process to maintain the reference, and the rank deficiency between the receiver clock bias, ALCB and the receiver phase bias is eliminated to obtain a full rank PPP-RTK network model taking ALCB into consideration; thirdly, positioning a user receiver by adopting a PPP-RTK server model considering ALCB and a satellite product provided by a traditional PPP-RTK server model, and judging whether a single difference ALCB between a user and a reference station is obvious or not before positioning; If the inter-station single difference ALCB is obvious, adopting a PPP-RTK user end model considering ALCB for positioning; If the inter-station single difference ALCB is not obvious, a traditional PPP-RTK user terminal model is adopted for positioning; The fourth step, respectively carrying out filtering and resolving on the two types of user terminal models, then spreading double-difference ambiguity parameters in the filtering and resolving process, introducing an integer estimatable theory in the ambiguity resolving stage, and converting the non-integer estimatable ambiguity into an integer estimatable form, thereby obtaining two types of user terminal models with fixed ambiguities; And fifthly, correspondingly selecting two types of user end models with fixed ambiguity according to network scene requirements of actual GNSS observation, and then inputting multi-system GNSS pseudo-range and carrier phase observation data to perform PPP-RTK real-time positioning calculation to obtain a high-precision positioning result.
2. The method for global system PPP-RTK positioning taking account of ambiguity-like code bias according to claim 1, wherein in said first step, the GNSS original observation equation of ambiguity-like code bias ALCB is specifically: ; Wherein, the Representing a desired operator; 、 respectively representing the receiver Tracked satellite At the frequency of The code and phase observations of the code and phase, Representing geometric distance, zenith troposphere delay By mapping functions Mapping to receiver And satellite Oblique distance between video lines, receiver clock error Clock error of satellite First order bias ionosphere delay Coefficient of dispersion , Representing the signal frequency; And Respectively a ambiguity-like code bias and a satellite code bias, And Representing receiver phase bias and satellite phase bias, respectively; in order to provide a phase ambiguity, For the corresponding wavelength(s), Inter-station single difference ionosphere constraints.
3. The method for positioning a global system PPP-RTK in consideration of ambiguity-like code bias according to claim 1, wherein in said second step, using ALCB of the first receiver as a reference reforming parameter, the rank deficiency between the satellite code bias and ALCB is eliminated, specifically: introducing a first virtual observation equation comprising these two types of parameters: ; Assume two sites , Two satellites were observed simultaneously , Each satellite transmits two frequencies , The virtual observation equation is expressed in the form of the following matrix: ; Wherein, the And Representing observed values and unknown parameters, respectively, column vectors The elements are arranged in sequence as follows: ; Column vector The following items are arranged in sequence: ; representing the kronecker product of the two, For a 4x4 identity matrix, due to the rank deficiency of the design matrix of the above equation, the ambiguity-like code bias of the first receiver is selected as a reference, and other parameters are reformed to obtain the following matrix equation: ; Wherein, the Is an estimated parameter vector after reforming, wherein the elements are arranged in order as follows: ; 。
4. The method for positioning a global system PPP-RTK in consideration of ambiguity-like code bias according to claim 3, wherein in said second step, a first epoch receiver clock difference is selected as a reference and a receiver phase bias maintenance reference is transferred in filtering to eliminate rank deficiency between receiver clock differences, ALCB and receiver phase bias, specifically: introducing a second virtual observation equation containing parameters to be analyzed: ; then a second virtual observation equation is developed using a matrix form: ; observation vector The elements in (a) are arranged in order as follows: ; Parameter vector The elements of (a) are arranged as follows: 。
5. the method for positioning the PPP-RTK of the whole system taking account of ambiguity-like code bias as set forth in claim 4, wherein said second virtual observation equation is of a full rank form as follows: ; reformed parameter vector The elements in (a) are arranged in order as follows: ; 。
6. The method for positioning the full system PPP-RTK taking account of ambiguity-like code bias as in claim 5, wherein said obtaining a ALCB full-rank PPP-RTK network model is specifically: ; ; Wherein, the Representing epoch indicators, for CDMA systems, since the wavelengths of different satellites are the same, the wavelength estimatable form is expressed as ; Ambiguity-estimatable form For GLONASS, the wavelength is expressed Wherein Representing fundamental frequency, the ambiguity is represented in an estimated form as Wherein , The explicit formulas for representing the frequency numbers, providing ionosphere independent combinations IF and geometry independent combinations are as follows: 。
7. The method for positioning a global system PPP-RTK with respect to ambiguity-like code bias according to claim 1, wherein in said third step, if the inter-station single difference ALCB is significant, a PPP-RTK client model with respect to ALCB is used for positioning, specifically: ; Wherein, the Representing a slave satellite To user receiver Is used for the vector of the unit of (a), Indicating the error in the positioning of the user, Is the ionospheric delay at the user's location interpolated from the network derived products.
8. The method for positioning the PPP-RTK in the whole system taking account of ambiguity-like code bias as in claim 7, wherein if the inter-station single difference ALCB is not significant, a traditional PPP-RTK client model is adopted for positioning, and the method is specifically as follows: 。
9. The method for positioning the whole system PPP-RTK taking account of ambiguity-like code bias is characterized by comprising the steps of performing filtering and resolving on the two types of client models, propagating double-difference ambiguity parameters in the filtering and resolving process, introducing an integer estimatable theory in the ambiguity resolving stage, converting non-integer estimatable ambiguity into an integer estimatable form, and obtaining two types of fixed-ambiguity client models, wherein the filtering process propagates double-difference ambiguity parameters, introducing the integer estimatable theory in the ambiguity resolving stage, converting the non-integer estimatable ambiguity into an integer estimatable form, and achieving reliable fixing of GLONASS ambiguities, and assuming that m GLONASS satellites exist, each satellite transmits the ambiguity of FDMA signals in the full-rank FDMA model can be expressed as a matrix form: ; the detailed expression is as follows: 。
10. A method for positioning PPP-RTK of whole system in consideration of ambiguity-like code bias, according to claim 9, wherein said realizing integer fixing of ambiguity, performing equivalent transformation on said ambiguity matrix based on integer estimatable theory, mapping original non-integer estimatable ambiguity parameters into a set of integer estimatable ambiguity parameters, specifically, by introducing a lower triangular transformation matrix, mapping the original ambiguity matrix Replaced by equivalent lower triangular matrix Thereby obtaining a matrix equation usable for integer ambiguity resolution The elements of the matrix are constructed as follows: ; 。

Description

Full-system PPP-RTK positioning method considering ambiguity-like code deviation Technical Field The invention relates to an improvement of a positioning technology considering ambiguity-like code deviation, belongs to the field of positioning, and particularly relates to a full-system PPP-RTK positioning method considering ambiguity-like code deviation. Background Since IFCB and SDB are terms related to the receiver, satellite and frequency simultaneously, and are similar in form to ambiguity of a phase observation equation, the two are collectively referred to as ALCB, and the existing PPP-RTK algorithm divides code bias into two parts, namely satellite code bias (SATELLITE CODE BIAS, SCB) related to the satellite only and receiver code bias (Receiver Code Bias, RCB) related to the receiver only, whereas the existing PPP-RTK algorithm does not consider ambiguity-like pseudo-range bias (including signal distortion bias in CDMA system and inter-frequency bias in FDMA system), resulting in uncompensated systematic bias in pseudo-range observation, causing difficulty in multi-system ambiguity fixing, confusion in parameter estimation and degradation in heterogeneous network resolving accuracy, and cannot realize high-precision real-time positioning of the full-system GNSS. The patent application with the application number of CN202110211637.5 and the application date of 2022 and 8-30 discloses a PPP-RTK positioning method and device taking into account the residual atmospheric errors, wherein the PPP-RTK positioning method taking into account the residual atmospheric errors comprises the steps of obtaining a plurality of groups of satellite data received by a plurality of base stations which are uniformly distributed, wherein each base station correspondingly receives one group of satellite data, carrying out non-differential non-combined PPP resolving on each group of satellite data in the plurality of groups of satellite data, estimating to obtain a plurality of residual atmospheric errors, fitting the plurality of residual atmospheric errors by using a fitting function to obtain residual atmospheric error correction, correcting the residual atmospheric errors of satellite positioning data by using the residual atmospheric error correction, and carrying out PPP-RTK positioning according to the corrected residual atmospheric errors and the received satellite positioning data to obtain the positioning result of a target object, wherein the scheme can eliminate the influence of the residual atmospheric errors on the actual positioning precision and the convergence time, so that the positioning performance is improved, but the positioning precision is influenced by neglecting ALCB. The disclosure of this background section is only intended to increase the understanding of the general background of the present patent application and should not be taken as an admission or any form of suggestion that this information forms the prior art already known to a person of ordinary skill in the art. Disclosure of Invention The invention aims to solve the problem that the influence of ALCB is ignored and the positioning accuracy is influenced in the prior art, and provides a full-system PPP-RTK positioning method considering ALCB influence and considering ambiguity-like code deviation, which improves the positioning accuracy. In order to achieve the above purpose, the technical solution of the invention is that a full system PPP-RTK positioning method considering ambiguity-like code deviation comprises the following steps: Firstly, establishing a multi-constellation multi-frequency point GNSS code observation and carrier phase observation model based on a CDMA and FDMA system, and then uniformly introducing ambiguity-like code bias ALCB parameters into the code observation model so as to obtain a GNSS original observation equation containing the ambiguity-like code bias ALCB; The second step, the eight kinds of rank deficiency of the GNSS original observation equation containing the ambiguity-like code bias ALCB is processed, wherein the rank deficiency between satellite code bias and ALCB is eliminated by taking ALCB of the first receiver as a reference reforming parameter, the first epoch receiver clock bias is selected as a reference, the receiver phase bias is transmitted in the filtering process to maintain the reference, and the rank deficiency between the receiver clock bias, ALCB and the receiver phase bias is eliminated to obtain a full rank PPP-RTK network model taking ALCB into consideration; thirdly, positioning a user receiver by adopting a PPP-RTK server model considering ALCB and a satellite product provided by a traditional PPP-RTK server model, and judging whether a single difference ALCB between a user and a reference station is obvious or not before positioning; If the inter-station single difference ALCB is obvious, adopting a PPP-RTK user end model considering ALCB for positioning; If the inter-station