CN-121978723-A - GNSS precise positioning precision prediction method based on PDOP error model

Abstract

The invention provides a GNSS precise positioning precision prediction method based on a PDOP error model, and belongs to the technical field of satellite navigation positioning. The method comprises the steps of selecting a plurality of ground monitoring stations on a service side, aiming at observation data of single epochs of each monitoring station, selecting different satellite combinations to implement precise positioning operation, recording PDOP values and coordinate result deviations of satellite combination positioning of each monitoring station selected each time under the single epochs, fitting all PDOP values of the single epochs and the corresponding coordinate result deviations into a polynomial function, taking coefficients of the polynomial function as precision prediction parameters sent to a user, calculating the PDOP values when the user implements precise positioning, calculating positioning reference values according to the precision prediction parameters, and evaluating the precision level of positioning results according to the reference values. The cloud service management method and the cloud service management system avoid the communication burden of continuously depending on the cloud service, do not need to increase the hardware computing power of the terminal, and are particularly suitable for the severe requirements of mobile terminals such as unmanned aerial vehicles on low power consumption and high real-time performance.

Inventors

• CHEN YONGCHANG
• YING JUNJUN
• ZHANG ZITENG
• WU ZIQIAN
• LIU YAXUAN
• WEI BAOGUO
• ZHANG JINGKUI
• WEI GUO
• WU KAI

Assignees

• 中国电子科技集团公司第五十四研究所
• 内蒙古自治区军民融合发展研究中心

Dates

Publication Date

20260505

Application Date

20260326

Claims (5)

1. 1. The GNSS precise positioning precision prediction method based on the PDOP error model is characterized by comprising the following steps of: Step 1, selecting a plurality of ground monitoring stations on a service side, and selecting different satellite combinations to implement precise positioning operation aiming at observation data of single epoch of each monitoring station; Step 2, recording PDOP values and coordinate result deviations of satellite combined positioning selected by each monitoring station under a single epoch; step 3, fitting all PDOP values of the single epoch and corresponding coordinate result deviations thereof into a polynomial function, and taking coefficients of the polynomial function as precision prediction parameters sent to a user; and 4, calculating a PDOP value when the user performs precision positioning, then calculating a positioning reference value according to the precision prediction parameter, and evaluating the precision level of the positioning result according to the reference value.
2. 2. The method for predicting the precision of GNSS precision positioning based on a PDOP error model according to claim 1, wherein the specific manner of step 1 is as follows: step 101, selecting a plurality of GNSS ground monitoring stations, implementing real-time positioning by combining precise satellite orbit and satellite clock difference information in a ionosphere PPP mode, and constructing a single epoch double-frequency original observation equation: Wherein, superscript Indicating satellite number, subscript Indicating the receiver number, subscript The number of the frequency band is indicated, For the pseudorange observations, As an observation of the phase of the carrier, For receivers To satellite Is used for the geometric distance of (a), Is a known satellite Is used for the purpose of determining the coordinates of (a), For unknown receivers Is used for the purpose of determining the coordinates of (a), In order to provide a tropospheric dry delay, As a tropospheric wet-retardation projection function, For the retardation of the zenith moisture of the troposphere, For receivers Is used for the time-lapse of (1), Is a satellite Is used for the time-lapse of (1), Is a satellite Ionospheric delay at frequency 1, For the ratio between other frequencies and the ionospheric delay at frequency 1, For the corresponding frequency Lambda 1 is the wavelength of the 1 st frequency, For receivers And satellite Frequency of the middle Corresponding ambiguity, except And The units of the other parameters are meters except the dimensionless ones; step 102, constructing a ionosphere combined observation equation: wherein the subscript Representing an ionosphere combiner operator, where , , F 1 is the frequency of the first frequency band, f 2 is the frequency of the second frequency band, and subscripts 1 and 2 respectively represent the first frequency band and the second frequency band; Step 103, for the receiver Number of satellites observed in a epoch The satellite numbers listed are 4,5, respectively, All satellite combinations in the time, the total number of the satellite combinations is A group; Step 104, for the receiver The observation data of the single epoch of the ith satellite group combination is substituted into the ionosphere combination observation equation by satellite orbit, satellite clock error product, troposphere dry delay and troposphere wet delay projection function, and the equation is solved to obtain parameters 、 、 、 And extracting PDOP value from normal equation ,i=1,2,..., 。
3. 3. The method for predicting the precision of GNSS precision positioning based on a PDOP error model according to claim 2, wherein the specific manner of step 2 is as follows: step 201, based on all the resolved receiver coordinates in step 104 True value of coordinates Calculating the deviation of the coordinate result ,i=1,2,..., ; Step 202, deviating the coordinate result According to the conversion method from rectangular coordinate system to station-core coordinate system, converting the coordinate deviation of lower east, north and elevation direction of station-core coordinate system 。
4. 4. The method for predicting the precision of GNSS precision positioning based on a PDOP error model according to claim 3, wherein the specific manner of step 3 is as follows: step 301, absolute value of coordinate deviation based on single epoch And Polynomial functions of east, north and elevation direction deviations and PDOP values are fitted separately: Wherein, the 、 、 Coefficients for three polynomial functions, j=0, 1,2,..m, The highest power of the fitting polynomial; Step 302, resolving the latest epoch in step 301 、 、 、 And sending the predicted parameters to a user as precision prediction parameters.
5. 5. The method for predicting the precision of GNSS precision positioning based on a PDOP error model according to claim 4, wherein the specific manner of step 4 is as follows: Step 401, the user adopts the same positioning technology as the service side to perform positioning, and obtains a positioning result after solving an algorithm equation according to a corresponding positioning process calculation method And PDOP value , Is represented by the latitude, longitude and elevation in the geodetic coordinate system, subscript The method comprises the steps of marking for a user; step 402, predicting parameters based on the received accuracy 、 、 、 Is combined with Substituting into polynomial to obtain reference value of positioning 、 And : Step 403, according to the reference value 、 And The accuracy level of the positioning result is evaluated.

Description

GNSS precise positioning precision prediction method based on PDOP error model Technical Field The invention relates to the technical field of satellite navigation positioning, in particular to a GNSS precise positioning precision prediction method based on a PDOP error model. Background The positioning accuracy of the Global Navigation Satellite System (GNSS) is significantly affected by the space geometrical distribution of satellites, and a position accuracy factor (PDOP) is a core index for evaluating the positioning reliability of the GNSS and directly reflects the amplifying effect of the space geometrical configuration of the satellites on positioning errors. In the current automatic driving, accurate agriculture and other scenes, when the PDOP value exceeds a threshold value, the system needs to be early-warned in time to avoid decision errors, and the key effect of the system on high-reliability application is highlighted. However, in the traditional positioning service, a user can roughly judge the reliability only through a PDOP threshold value, and the technical defects that the nonlinear relation between the PDOP and the real error is not modeled, so that the PDOP can only reflect geometric precision attenuation and cannot predict specific error magnitude, the coordinate true value deviation of a monitoring station in a foundation enhancement system (such as a CORS network) and the space-time correlation characteristic of the PDOP are not deeply mined, so that data value is wasted, and a main stream GNSS receiver can output the PDOP in real time but the user cannot convert the PDOP into quantifiable precision expectation. Along with the completion of Beidou No. three global networking and the development of the emerging scientific and technological field, the requirements of intelligent user terminals such as automatic driving, low-altitude unmanned aerial vehicles and the like on real-time position accuracy are increasingly urgent. How to provide reliable positioning precision information for users by utilizing the ground reference station or monitoring station resources is a problem to be solved currently and urgently, and is a bottleneck for promoting the development of GNSS high-precision position services to deeper and wider fields. Disclosure of Invention Aiming at the problem that PDOP only can qualitatively evaluate geometric accuracy but cannot quantitatively predict actual errors in GNSS positioning, the invention provides a GNSS precise positioning accuracy prediction method based on a PDOP error model. According to the method, an error transfer model is built based on PDOP values and positioning results of multiple monitoring stations in the positioning process and known coordinate true values of the monitoring stations, a mapping relation between PDOP and positioning deviation is inverted by utilizing a coordinate deviation data set, a polynomial fitting is adopted to generate a lightweight coefficient, and a user can calculate expected positioning accuracy only by using the local PDOP values. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: a GNSS precise positioning precision prediction method based on a PDOP error model comprises the following steps: Step 1, selecting a plurality of ground monitoring stations on a service side, and selecting different satellite combinations to implement precise positioning operation aiming at observation data of single epoch of each monitoring station; Step 2, recording PDOP values and coordinate result deviations of satellite combined positioning selected by each monitoring station under a single epoch; step 3, fitting all PDOP values of the single epoch and corresponding coordinate result deviations thereof into a polynomial function, and taking coefficients of the polynomial function as precision prediction parameters sent to a user; and 4, calculating a PDOP value when the user performs precision positioning, then calculating a positioning reference value according to the precision prediction parameter, and evaluating the precision level of the positioning result according to the reference value. Further, the specific mode of the step 1 is as follows: step 101, selecting a plurality of GNSS ground monitoring stations, implementing real-time positioning by combining precise satellite orbit and satellite clock difference information in a ionosphere PPP mode, and constructing a single epoch double-frequency original observation equation: Wherein, superscript Indicating satellite number, subscriptIndicating the receiver number, subscriptThe number of the frequency band is indicated,For the pseudorange observations,As an observation of the phase of the carrier,For receiversTo satelliteIs used for the geometric distance of (a),Is a known satelliteIs used for the purpose of determining the coordinates of (a),For unknown receiversIs used for the purpose of determining the coordinates of (a),In order