CN117826208A - GNSS differential positioning method, system and equipment for reference station measurement data - Google Patents

Abstract

The invention relates to a GNSS differential positioning method, a system and equipment for reference station measurement data, wherein the method comprises the following steps: setting a reference station receiver for GNSS differential positioning at a preset coordinate position point, receiving an original pseudo-range observation value sent by a GNSS satellite, and carrying out error correction on the original pseudo-range observation value to obtain a first corrected pseudo-range observation value; positioning and resolving are carried out based on the first corrected pseudo-range observation value, and receiver resolving coordinates and receiver clock errors of a reference station receiver are obtained; acquiring a coordinate error of a receiver resolving coordinate based on a preset coordinate position point and the receiver resolving coordinate, and acquiring a correction of a first corrected pseudo-range observation value based on the receiver resolving coordinate, the coordinate error and a receiver clock error; and correcting the first corrected pseudo-range observation value based on the correction to obtain a second corrected pseudo-range observation value, and broadcasting the second corrected pseudo-range observation value to the mobile station user by the reference station receiver for positioning.

Description

GNSS differential positioning method, system and equipment for reference station measurement data

Technical Field

The present invention relates to the field of satellite positioning, and in particular, to a method, a system, and an apparatus for GNSS differential positioning of reference station measurement data.

Background

The sources of errors in global navigation satellite systems (Global Navigation Satellite System, GNSS) such as GPS, beidou, galileo, GLONASS are highly correlated in space and time. It is based on this feature that GNSS differential positioning techniques and systems improve overall system performance. For example, in a simple local GNSS differential positioning system with only one reference station, the errors in the pseudorange and carrier phase measurements of the reference station receiver to the satellites in view may be considered very similar to the errors of nearby users. Since the coordinate locations of the reference stations are known a priori with accuracy, the self pseudorange and carrier phase measurements along with the self-accurate known coordinate location information may be broadcast to users over the communication link. The user receives the coordinate position and satellite measurement information from the reference station receiver, and can construct a differential observation value, eliminate most of common errors between the user and the reference station receiver (for example, satellite orbit, satellite clock error and atmospheric delay errors can be eliminated for single-difference combination, and receiver clock error can be further eliminated for double-difference combination), so that high-precision positioning is realized. In addition to directly broadcasting the original observed information, the reference station may also calculate an observed value correction by itself known coordinate locations and broadcast it to the subscriber rover. These two different treatments are in principle equivalent.

It follows that for GNSS differential positioning systems, the quality of the raw measurements of the reference station receiver is critical to the overall differential positioning accuracy and performance. As described above, the conventional GNSS differential positioning system generally transmits the raw measurement values of the reference station receiver directly to the user mobile station, and does not perform the positioning calculation process, and does not consider correction of the measurement values of the reference station receiver, such as the raw pseudoranges and carriers. In practice, however, the original measurements of the reference station receiver have other measurement errors in addition to the common error component with the measurements of the subscriber rover receiver. The errors are not part of the common errors and cannot be eliminated through difference, so that the errors are amplified in the single-difference and double-difference combination process, and the positioning performance of the mobile station of the user is further affected.

Disclosure of Invention

The invention aims to provide a GNSS differential positioning method, a GNSS differential positioning system and GNSS differential positioning equipment for reference station measurement data.

In order to achieve the above object, the present invention provides a GNSS differential positioning method for reference station measurement data, including:

s1, setting a reference station receiver for GNSS differential positioning at a preset coordinate position point, receiving an original pseudo-range observation value sent by a GNSS satellite, and performing error correction on the original pseudo-range observation value to obtain a first corrected pseudo-range observation value rho _j Wherein the subscript j represents the jth GNSS satellite;

s2, based on the first corrected pseudo-range observation value rho _j Positioning calculation is carried out, and receiver calculation coordinates and receiver clock differences of the reference station receiver are obtained;

s3, based on the sum of the preset coordinate position pointsThe receiver resolving coordinates obtain a coordinate error of the receiver resolving coordinates, and obtain the first corrected pseudo-range observation ρ based on the receiver resolving coordinates, the coordinate error, and the receiver clock error _j Correction of δρ _j ；

S4, based on the correction quantity delta rho _j For the first modified pseudorange observations ρ _j Performing correction to obtain second corrected pseudo-range observationAnd said reference station receiver adding said second modified pseudorange observation +.>And broadcasting to the mobile station users for positioning.

According to one aspect of the present invention, in step S3, in the step of obtaining a coordinate error of the receiver resolved coordinates based on the preset coordinate position point and the receiver resolved coordinates, the coordinate error is expressed as:

wherein δx _u 、δy _u 、δz _u Representing the coordinate error value, x ₀ 、y ₀ 、z ₀ Coordinate value, x representing a preset coordinate position point _u 、y _u 、z _u Coordinate values representing the receiver resolved coordinates.

According to one aspect of the invention, in step S3, the first corrected pseudorange observation ρ is obtained based on the receiver resolved coordinates, the coordinate error, and the receiver clock error _j Correction of δρ _j In the step (a), the correction δρ _j Expressed as:

wherein x is _j 、y _j 、z _j Representing three-dimensional position coordinate values of a jth GNSS satellite, which is obtained based on broadcast satellite ephemeris calculation, c represents vacuum light velocity, t _u Representing receiver clock error, r _j Representing the geometric distance between the jth GNSS satellite and the reference station receiver, expressed as:

according to one aspect of the present invention, in step S1, error correction is performed on the raw pseudorange observations to obtain a first corrected pseudorange observation ρ _j In the step (a), the error correction is at least one of ionosphere delay correction, troposphere correction, earth rotation correction, relativistic effect correction and earth rotation correction.

According to one aspect of the invention, in step S2, based on the first corrected pseudorange observations ρ _j In the step of performing positioning calculation to obtain the receiver calculation coordinates and receiver clock error of the reference station receiver, the first corrected pseudo-range observed value ρ is obtained by using a least square method, a weighted least square method or a kalman filter method _j And (5) performing positioning calculation.

According to one aspect of the invention, in step S4, δρ is based on the correction _j For the first modified pseudorange observations ρ _j Performing correction to obtain second corrected pseudo-range observationIn the step (a), said second modified pseudorange observation +.>Expressed as:

to achieve the above object, the present invention provides a system for the foregoing GNSS differential positioning method, including:

the data correction module is used for collecting an original pseudo-range observation value received by the reference station receiver and carrying out error correction on the original pseudo-range observation value to obtain a first corrected pseudo-range observation value rho _j Wherein the subscript j represents the jth GNSS satellite;

a data calculation module based on the first corrected pseudo-range observation value ρ _j Positioning calculation is carried out, and receiver calculation coordinates and receiver clock differences of the reference station receiver are obtained;

a correction calculation module, configured to obtain a coordinate error of the receiver resolved coordinates based on the preset coordinate position point and the receiver resolved coordinates, and obtain the first corrected pseudo-range observation value ρ based on the receiver resolved coordinates, the coordinate error, and the receiver clock error _j Correction of δρ _j ；

Positioning result output module based on the correction δρ _j For the first modified pseudorange observations ρ _j Performing correction to obtain second corrected pseudo-range observationAnd, the second corrected pseudo-range observation value +.>Transmitting to said reference station receiver and based on said reference station receiver, said second corrected pseudorange observations +.>And broadcasting to the mobile station users for positioning.

To achieve the above object, the present invention provides an apparatus for applying the foregoing GNSS differential positioning method, including at least one processor, at least one memory and a data bus;

the processor and the memory complete communication with each other through the data bus;

the memory stores program instructions executable by the processor, the processor invoking the program instructions to perform the GNSS differential positioning method.

To achieve the above object, the present invention provides a computer readable memory for the GNSS differential positioning method, which stores a computer program for implementing the GNSS differential positioning method when executed by a processor.

According to the scheme of the invention, the invention can fully utilize the characteristic that the position coordinates of the reference station receiver are known accurately a priori, calculate and estimate the error of the original measured value of the reference station receiver, and correct the original observed value of the reference station receiver accordingly, thereby further improving the observation quality of the original data of the reference station receiver and improving the overall positioning performance of the GNSS differential positioning system.

According to the scheme of the invention, the projection correction of the positioning error of the reference station receiver in the satellite observation direction is calculated by expanding the first partial derivative of the pseudo-range observation equation, so that the correction of the pseudo-range observation quantity of the reference station receiver is realized, and the precision and the performance of the whole GNSS differential positioning system are improved.

According to the scheme of the invention, the position error of the reference station receiver is obtained by fully utilizing the characteristic that the position coordinate of the reference station receiver is known accurately a priori, and the projection correction of the reference station receiver in the satellite observation direction is obtained by calculation, so that the correction of the satellite pseudo-range observation quantity of the reference station receiver can be realized under the condition of not depending on external equipment or facilities, the observation quality of the original data of the reference station receiver is improved, and the integral positioning performance of the GNSS differential positioning system is improved.

Drawings

FIG. 1 is a block diagram schematically illustrating steps of a GNSS differential positioning method according to the present invention.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.

In describing embodiments of the present invention, the terms "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer" and the like are used in terms of orientation or positional relationship based on that shown in the drawings, which are merely for convenience of description and to simplify the description, rather than to indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and thus the above terms should not be construed as limiting the present invention.

The present invention will be described in detail below with reference to the drawings and the specific embodiments, which are not described in detail herein, but the embodiments of the present invention are not limited to the following embodiments.

As shown in fig. 1, according to an embodiment of the present invention, a GNSS differential positioning method of reference station measurement data of the present invention includes:

s1, setting a reference station receiver for GNSS differential positioning at a preset coordinate position point, receiving an original pseudo-range observation value sent by a GNSS satellite, and performing error correction on the original pseudo-range observation value to obtain a first corrected pseudo-range observation value rho _j Wherein the subscript j represents the jth GNSS satellite;

s2, based on first corrected pseudo-range observation value rho _j Positioning calculation is carried out, and receiver calculation coordinates and receiver clock errors of a reference station receiver are obtained;

s3, acquiring a coordinate error of a receiver resolving coordinate based on a preset coordinate position point and the receiver resolving coordinate, and acquiring a first corrected pseudo-range observation value rho based on the receiver resolving coordinate, the coordinate error and the receiver clock error _j Correction of δρ _j ；

S4, based on correction quantity delta rho _j For a first modified pseudorange observation ρ _j Performing correction to obtain a second corrected pseudo-rangeObservations ofAnd the reference station receiver correcting the second corrected pseudo-range observation value +.>And broadcasting to the mobile station users for positioning.

According to one embodiment of the present invention, in step S1, an error correction is performed on an original pseudo-range observation to obtain a first corrected pseudo-range observation ρ _j In the step (a), the error correction is at least one of ionosphere delay correction, troposphere correction, earth rotation correction, relativistic effect correction, and earth rotation correction. In particular, among various error sources, the ionosphere is one of the most troublesome error sources affecting the service performance of the global navigation satellite system. The united states GPS, the european union Galileo and the chinese Beidou (BDS) broadcast ionospheric model parameters in their broadcast ephemeris. The united states GPS system and the european union Galileo system provide global ionospheric modification services using 8-parameter Klobuchar model (GPSklob) and NeQuick model, respectively. The beidou No. two system provides ionospheric modification services covering the asia-pacific region using a modified 8-parameter Klobuchar model (BDSklob). The Beidou No. three global navigation satellite system (hereinafter referred to as a Beidou No. three system) adopts a Beidou global broadcast ionospheric delay correction model (BeiDou Global Broadcast Ionospheric Delay Correction Model, BDGIM) developed by autonomous design. The Beidou No. three system broadcasts 9 BDGIM model parameters in real time, and provides real-time ionosphere correction service for global users. Thus, ionospheric delay corrections may be implemented based on the broadcasted model parameters.

The troposphere is located at the bottom of the atmosphere and its top is about 40km from the ground, where various atmospheric phenomena occur mainly. Oxygen and nitrogen are the main causes of propagation delay of GPS signals. The troposphere concentrates 99% of the mass of the atmosphere, the lower part of the atmosphere, which is non-dispersive for frequencies up to 15 GHz. In such a medium, both the phase velocity and group velocity associated with the GPS carrier and signal information (PRN code and navigation data) on L1 and L2 are equally delayed relative to free space propagation. This retardation varies with the tropospheric refractive index, which is dependent on local temperature, pressure and relative humidity. If not compensated, the equivalent distance of such delays can vary from around 2.4m for satellites at zenith and at sea level to around 25m for satellites at about 5 elevation. In this embodiment, the tropospheric delay error is usually corrected by using a dry and wet component model.

The effect of relativistic effects on satellite positioning is manifested both in the pseudorange and carrier phase measurements, whenever a signal source (in this case a GNSS satellite) or a signal receiver (GNSS receiver) is moved relative to a selected isotropic speed of light coordinate system (in a GNSS system, the isotropic speed of light coordinate is the earth's inertia (ECI) coordinate system), a relativistic correction of the ambiguous relativistic (SR) is required. Relativistic corrections with Generalized Relativistic (GR) are required whenever the signal source and the signal receiver are at different gravitational potentials. Satellite clocks are affected by both the knight-errant and generalized relatives. To compensate for both effects, the satellite clock frequency is tuned to 10.22999999543MHz prior to transmission. The frequency observed by the user at sea level will be 10.23MHz, so the user does not have to correct for this effect. But the user needs to correct for another relativistic periodic effect due to slight eccentricities in the satellite orbit. Exactly half of the periodic effect is caused by periodic variations in the velocity of the satellite relative to the ECI coordinate system, while the other half is caused by periodic variations in the gravitational potential of the satellite.

When the satellite is near the ground, the satellite speed is faster and the gravitational potential is lower-both of which slow down the satellite clock operation; when the satellite is at a remote location, the satellite speed is slow and the gravitational potential is high-both of which may cause the satellite clock to run faster. The literature shows that this relativistic effect can reach a maximum of 70ns (distance of 21 m). The relativistic effect correction of the satellite clock allows the user to estimate the time of transmission more accurately.

In addition, since the earth is spinning during the time of signal transmission, a relativistic error, known as the Sagnac effect, is introduced in calculating the satellite position in the ECEF coordinate system. During the propagation time of satellite signal transmission, the clock on the earth's surface will rotate in a limited manner relative to the stationary geocentric coordinate system. Obviously, if the rotation that the user makes is off the satellite, the propagation time will increase and vice versa. If no correction is made, the Sagnac effect can cause a position error of around 30m and is therefore not negligible. Correction of the Sagnac effect is also commonly referred to as earth rotation correction.

According to one embodiment of the invention, in step S2, based on the first corrected pseudorange observations ρ _j In the step of obtaining the receiver resolving coordinates and receiver clock error of the reference station receiver, the first corrected pseudo-range observation value ρ is obtained by adopting a least square method, a weighted least square method or a Kalman filtering method _j And (5) performing positioning calculation. In the present embodiment, a least squares algorithm (Least Square Method) is taken as an example, to determine the receiver solution coordinates (x _u ，y _u ，z _u )(i.e. for mobile station) Household coordinatesClock difference t with receiver _u Pseudo-range measurement needs to be carried out on at least 4 satellites to obtain an equation set:

ρ _j ＝||s _j -u||+ct _u (1)

wherein s is _j Representation ofGNSS satellite position three-dimensional coordinatesU representsThree-dimensional coordinates of mobile station user locationWhere j ranges from 1 to 4, representing different GNSS satellites, the above equation set is extended by x _u 、y _u 、z _u And t _u Simultaneous equations of the unknowns are expressed as:

wherein x is _j 、y _j 、z _j And the three-dimensional position coordinate value of the jth GNSS satellite is represented.

If the position of the receiver is approximately known, the receiver can be solved for the coordinates (i.e., true position) (x _u ，y _u ，z _u ) And approximate positionDisplacement for deviation (Deltax _u ,Δy _u ,Δz _u ) To mark. The satellite observation equation is expanded at the approximate position according to the Taylor series, so that the position offset delta x can be obtained _u ,Δy _u ,Δz _u ) Expressed as a linear function of known coordinates and pseudorange measurements:

using approximate positionsAnd time offset estimate +.>An approximate pseudo-range can be calculated>

As previously described, is considered unknownMobile station user coordinatesAnd the receiver clock bias is composed of an approximation component and an increment component, namely:

therefore, there are:

the above may be around the approximation point and associated predicted value of the receiver clock biasExpansion into Taylor series:

to eliminate nonlinear terms, the term following the first partial derivative is omitted from the above expansion. Each partial derivative is calculated as:

in the method, in the process of the invention,

substitution of formula (4) and formula (8) into formula (7) yields:

thus, the linearization of the relative unknowns Δxu, Δyu, Δzu, and Δtu of equation (3) is completed. Rearranging the above formula such that the known amount is on the left and the unknown amount is on the right, yields:

for convenience, the following new variables are introduced to simplify formula (11):

wherein a is _xj ,a _yj And a _zj Each item is represented byApproximate location of a rover userA unit vector pointing to the directional cosine of the j-th satellite. Definition of unit vector for the j-th satelliteThe method comprises the following steps:

a _j ＝(a _xj ,a _yj ,a _zj ) (13)

thus, equation (11) can be simply written as:

Δρ _j ＝a _xj Δx _u +a _yj Δy _u +a _zj Δz _u -cΔt _u (14)

further, the aforementioned 4 unknowns Δx are calculated _u ,Δy _u ,Δz _u And Deltat _u More than 4 satellites are used for distance measurement so as to solve the unknown number. And is defined in the form of the following matrix:

finally, the method comprises the following steps:

Δρ＝HΔx (18)

the least squares solution is:

Δx＝H ^-1 Δρ (19)

in the present embodiment, the formula (19) is iteratively solved until the update amount converges (no longer changes), thereby obtainingMobile station user coordinates(x _u ，y _u ，z _u )。

According to an embodiment of the present invention, in step S3, in the step of obtaining the coordinate error of the receiver resolved coordinates based on the preset coordinate position point and the receiver resolved coordinates, the coordinate error is expressed as:

wherein δx _u 、δy _u 、δz _u Representing the coordinate error value, x ₀ 、y ₀ 、z ₀ Coordinate value, x representing a preset coordinate position point _u 、y _u 、z _u Coordinate values representing the receiver resolved coordinates.

According to one embodiment of the invention, in step S3, a first corrected pseudorange observation ρ is obtained based on the receiver resolved coordinates, the coordinate error and the receiver clock difference _j Correction of δρ _j In the step (a), correction δρ _j Expressed as:

wherein x is _j 、y _j 、z _j Representing three-dimensional position coordinate values of a jth GNSS satellite, which is obtained based on broadcast satellite ephemeris calculation, c represents vacuum light velocity, t _u Representing receiver clock error, r _j Representing the geometric distance between the jth GNSS satellite and the reference station receiver, expressed as:

_u by the correction of the above arrangement, the coordinate correction δx is utilized by the way of first partial derivative expansion,δ _u y、δ _{u j} And z, the pseudo-range correction δρ can be solved quickly, and the calculation efficiency is effectively ensured.

According to one embodiment of the invention, in step S4, the correction δρ is based on _j For a first modified pseudorange observation ρ _j Performing correction to obtain second corrected pseudo-range observationIn step (a), second modified pseudo-range observations +.>Expressed as:

according to an embodiment of the present invention, a system for the foregoing GNSS differential positioning method is provided, including:

the data correction module is used for collecting an original pseudo-range observation value received by the reference station receiver, and performing error correction on the original pseudo-range observation value to obtain a first corrected pseudo-range observation value rho _j Wherein the subscript j represents the jth GNSS satellite;

the data resolving module is based on the first corrected pseudo-range observation value rho _j Positioning calculation is carried out, and receiver calculation coordinates and receiver clock errors of a reference station receiver are obtained;

the correction calculation module is used for acquiring coordinate errors of the receiver resolving coordinates based on the preset coordinate position points and the receiver resolving coordinates, and acquiring a first corrected pseudo-range observation value rho based on the receiver resolving coordinates, the coordinate errors and the receiver clock error _j Correction of δρ _j ；

Positioning result output module based on correction delta rho _j For a first modified pseudorange observation ρ _j Performing correction to obtain second corrected pseudo-range observationAnd, second corrected pseudo-range observation +.>To the reference station receiver and based on the reference station receiver transmitting a second corrected pseudo-range observation +.>And broadcasting to the mobile station users for positioning.

According to an embodiment of the present invention, the present invention provides an apparatus for applying the foregoing GNSS differential positioning method, including at least one processor, at least one memory and a data bus; in this embodiment, the processor and the memory complete communication with each other through the data bus; the memory stores program instructions executable by the processor, and the processor invokes the program instructions to execute the GNSS differential positioning method.

In the present embodiment, the Memory may be, but is not limited to, a random access Memory (Random Access Memory, RAM), a Read Only Memory (ROM), a programmable Read Only Memory (Programmable Read-Only Memory, PROM), an erasable Read Only Memory (Erasable Programmable Read-Only Memory, EPROM), an electrically erasable Read Only Memory (Electric Erasable Programmable Read-Only Memory, EEPROM), or the like.

In this embodiment, the processor may be an integrated circuit chip having signal processing capabilities. The processor may be a general-purpose processor including a central processing unit (Central Processing Unit, CPU), a network processor (Network Processor, NP), etc.; but also digital signal processors (Digital Signal Processing, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), field programmable gate arrays (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

According to an embodiment of the present invention, there is provided a computer readable memory having stored thereon a computer program for implementing a GNSS differential positioning method when executed by a processor.

The foregoing is merely exemplary of embodiments of the invention and, as regards devices and arrangements not explicitly described in this disclosure, it should be understood that this can be done by general purpose devices and methods known in the art.

The above description is only one embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (9)

1. A GNSS differential positioning method of reference station measurement data, comprising:

s1, setting a reference station receiver for GNSS differential positioning at a preset coordinate position point, receiving an original pseudo-range observation value sent by a GNSS satellite, and performing error correction on the original pseudo-range observation value to obtain a first corrected pseudo-range observation value rho _j Wherein the subscript j represents the jth GNSS satellite;

s2, based on the first corrected pseudo-range observation value rho _j Positioning calculation is carried out, and receiver calculation coordinates and receiver clock differences of the reference station receiver are obtained;

s3, acquiring a coordinate error of the receiver resolving coordinate based on the preset coordinate position point and the receiver resolving coordinate, and acquiring the first corrected pseudo-range observation value rho based on the receiver resolving coordinate, the coordinate error and the receiver clock error _j Correction of δρ _j ；

S4, based on the correction quantity delta rho _j For the first modified pseudorange observations ρ _j Performing correction to obtain second corrected pseudo-range observationAnd said reference station receiver adding said second modified pseudorange observation +.>And broadcasting to the mobile station users for positioning.

2. The GNSS differential positioning method according to claim 1, wherein in the step S3 of obtaining the coordinate error of the receiver resolved coordinates based on the preset coordinate position point and the receiver resolved coordinates, the coordinate error is expressed as:

wherein δx _u 、δy _u 、δz _u Representing the coordinate error value, x ₀ 、y ₀ 、z ₀ Coordinate value, x representing a preset coordinate position point _u 、y _u 、z _u Coordinate values representing the receiver resolved coordinates.

3. The GNSS differential positioning method according to claim 2, characterized in that in step S3, the first corrected pseudo-range observation ρ is obtained based on the receiver resolved coordinates, the coordinate error and the receiver clock difference _j Correction of δρ _j In the step (a), the correction δρ _j Expressed as:

wherein x is _j 、y _j 、z _j Representing three-dimensional position coordinate values of a jth GNSS satellite, which is obtained based on broadcast satellite ephemeris calculation, c represents vacuum light velocity, t _u Representing receiver clock error, r _j Representing the geometric distance between the jth GNSS satellite and the reference station receiver, expressed as:

4. the GNSS differential positioning method according to claim 3, wherein in step S1, error correction is performed on the original pseudo-range observation value to obtain a first corrected pseudo-range observation value ρ _j In the step (a), the error correction is at least one of ionosphere delay correction, troposphere correction, earth rotation correction, relativistic effect correction and earth rotation correction.

5. The GNSS differential positioning method of claim 4, wherein in step S2, based on the first corrected pseudorange observations ρ _j In the step of performing positioning calculation to obtain the receiver calculation coordinates and receiver clock error of the reference station receiver, the first corrected pseudo-range observed value ρ is obtained by using a least square method, a weighted least square method or a kalman filter method _j And (5) performing positioning calculation.

6. The GNSS differential positioning method according to claim 5, characterized in that in step S4, based on the correction δρ _j For the first modified pseudorange observations ρ _j Performing correction to obtain second corrected pseudo-range observationIn the step (a), said second modified pseudorange observation +.>Expressed as:

7. a system for the GNSS differential positioning method of any of claims 1 to 6, comprising:

the data correction module is used for collecting an original pseudo-range observation value received by the reference station receiver and carrying out error correction on the original pseudo-range observation value to obtain a first corrected pseudo-range observation value rho _j Wherein the subscript j represents the jth GNSS satellite;

a data calculation module based on the first corrected pseudo-range observation value ρ _j Positioning calculation is carried out, and receiver calculation coordinates and receiver clock differences of the reference station receiver are obtained;

the correction calculation module is based on the preset coordinate position point and the jointReceiver-resolved coordinates obtain a coordinate error of the receiver-resolved coordinates, and obtain the first corrected pseudorange observation ρ based on the receiver-resolved coordinates, the coordinate error, and the receiver clock error _j Correction of δρ _j ；

Positioning result output module based on the correction δρ _j For the first modified pseudorange observations ρ _j Performing correction to obtain second corrected pseudo-range observationAnd, the second corrected pseudo-range observation value +.>Transmitting to said reference station receiver and based on said reference station receiver, said second corrected pseudorange observations +.>And broadcasting to the mobile station users for positioning.

8. An apparatus for applying the GNSS differential positioning method of any of claims 1 to 6, comprising at least one processor, at least one memory and a data bus;

the processor and the memory complete communication with each other through the data bus;

the memory stores program instructions executable by the processor, the processor invoking the program instructions to perform the GNSS differential positioning method.

9. A computer readable memory for use in a GNSS differential positioning method according to any of the claims 1 to 6, characterized in that a computer program is stored thereon, which computer program, when executed by a processor, implements the GNSS differential positioning method.