CN104483689B - Determination method for BDS reference station three-frequency carrier phase whole cycle ambiguities - Google Patents

Abstract

The invention discloses a determination method for BDS reference station three-frequency carrier phase whole cycle ambiguities, and belongs to the field of satellite positioning systems and positioning measuring technologies. According to the method, by the utilization of the integer linear relation among the BDS three-frequency carrier phase whole cycle ambiguities, the whole cycle ambiguities of BDS reference station three-frequency carrier phase observation values are accurately determined; through the method, the BDS reference station network three-frequency carrier phase whole cycle ambiguities can be determined in a single-epoch mode, and the problem that the geometrical configuration of a BDS observation satellite changes slowly, so that the BDS reference station network carrier phase whole cycle ambiguities are difficult to rapidly determine in real time is solved. Meanwhile, without considering whether cycle slips exist in BDS reference station carrier phase observation data or not, detecting and process of cycle slips of the observation data are avoided, the whole cycle ambiguities are determined with the single double-difference satellite as the object without calculating a BDS reference station network carrier phase observation equation set, and the calculation amount for determining the BDS reference station network carrier phase whole cycle ambiguities is small.

Description

BDS reference station three-frequency carrier phase integer ambiguity determination method

Technical Field

The invention belongs to the technical field of satellite positioning systems and positioning measurement, and particularly relates to a method for determining integral cycle ambiguity of a three-frequency carrier phase of a BDS reference station.

Background

At present, a Beidou satellite navigation System (BDS) with independent intellectual property rights in China is called BDS for short, and formally provides navigation positioning service for Asia-Pacific regions; due to the influence of various observation errors, the precision of the standard positioning service provided by the BDS system is about 10m, and the standard positioning service of the BDS system can only meet the requirement of low-precision navigation positioning; the BDS reference station network is used for providing a BDS regional error correction model or correction number, so that error correction of BDS users in the coverage range of the reference station network can be realized, the observation error influence of the BDS users is eliminated or greatly weakened, and high-precision real-time dynamic positioning of the BDS users is realized; the premise for realizing error correction of the BDS users is that high-precision error correction numbers provided by the BDS reference station network are required, and the core problem is accurate fixation of the whole-cycle ambiguity of the BDS reference station network carrier phase observation data.

As the BDS system is just built, the high-precision real-time dynamic positioning service technology and means based on the BDS reference station network are not mature; at present, the relatively mature service means and technology are mainly a GPS user positioning method based on a GPS reference station network; the positioning principle and the signal structure of the BDS system in China are similar to those of the GPS, and the GPS is the most mature and stable satellite navigation positioning system at present; therefore, the BDS high-precision positioning method mostly refers to or adopts a high-precision positioning method of a GPS system, but the broadcast ephemeris satellite orbit precision of the BDS is inferior to the GPS system, and particularly, most of the in-orbit working satellites of the BDS system are GEO satellites and IGSO satellites, so that the problem of real-time and rapid resolving of the carrier phase whole-cycle ambiguity of the BDS reference station network cannot be well solved by adopting the processing method of the GPS carrier phase observation value whole-cycle ambiguity, and particularly, accurate determination of a single epoch of the carrier phase whole-cycle ambiguity of the BDS reference station cannot be realized.

The motion period of an IGSO satellite in a BDS system is about 24 hours, the GEO satellite is static relative to the earth, and the change of the geometric configuration of the BDS in-orbit working satellite observed by a reference station is small in a short time of real-time fast ambiguity resolution (namely real-time fast start of the reference station network) of the carrier phase whole-cycle ambiguity of the BDS reference station network; therefore, the geometric configuration of the observation satellite caused by the BDS satellite constellation (more GEO and IGSO satellites) is not good, which is not beneficial to determining the ambiguity of the whole cycle of the carrier phase of the BDS reference station; meanwhile, whether cycle slip exists in BDS carrier phase observation data or not needs to be considered; if single epoch solution of the BDS reference station network carrier phase observation value integer ambiguity can be realized, the problem of slow change of the BDS satellite geometric configuration does not influence the single epoch solution of the carrier phase integer ambiguity, and the problem of whether cycle slip exists in the BDS carrier phase observation data or not does not need to be considered.

The BDS system realizes the broadcasting of the three-frequency observation data in a full constellation, while the GPS system does not have the broadcasting function of the three-frequency observation data in the full constellation; the existing GPS reference station network carrier phase integer ambiguity resolution methods are based on GPS dual-frequency observation data, and the methods cannot realize resolution of BDS reference station three-frequency carrier phase integer ambiguity; if the BDS system three-frequency carrier phase observation data are fully utilized, the single epoch accurate resolving of the BDS reference station carrier phase whole-cycle ambiguity is realized, the advantages of the BDS relative to the GPS system are embodied, and the BDS system three-frequency carrier phase observation data have important significance; however, at present, a method for determining the integer ambiguity unit epoch of the BDS reference station three-frequency carrier phase observation data is lacked.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method for determining the integer ambiguity of the three-frequency carrier phase of the BDS reference station, which utilizes unique full-constellation three-frequency carrier phase observation data of the BDS to accurately determine the integer ambiguity of the carrier phase of the BDS reference station network, overcomes the problems that the geometric configuration of a BDS observation satellite is slow in change and is not beneficial to the real-time and rapid determination of the integer ambiguity of the carrier phase of the BDS reference station network, avoids the work of detecting and processing the cycle slip of the observation data, and reduces the work load when the integer ambiguity of the BDS reference station network is resolved.

A BDS reference station three-frequency carrier phase integer ambiguity determination method comprises the following steps:

step 1, broadcasting tri-band carrier phase observation data to a BDS reference station receiver by each BDS satellite, and performing double-difference combination processing on the tri-band carrier phase observation data received by the BDS reference station receiver to eliminate clock difference of the BDS satellite and clock difference of the BDS reference station receiver and weaken troposphere delay error, ionosphere delay error and satellite orbit error in the BDS reference station observation data;

step 2, multiplying the triple-frequency carrier phase observation data subjected to double-difference combination processing by a real number to obtain a double-difference carrier phase observation equation of which three frequency carrier phase observation values contain real number coefficients, and adding and integrating the double-difference carrier phase observation equations of the three frequencies to obtain an integrated double-difference carrier phase observation equation of the three frequencies after integration;

step 3, constructing a mutual integer linear relation between three-frequency carrier phase integer ambiguities of the BDS reference station according to an integrated double-difference carrier phase observation equation of the three integrated frequencies, and specifically comprising the following steps:

3-1, according to the integrated double-difference carrier phase observation equation of the three frequencies after integration and the double-difference ionosphere delay error residual relation borne by the B1, B2 and B3 double-difference carrier phase observation values, obtaining the integrated double-difference carrier phase observation equation of the three frequencies after the double-difference ionosphere delay error residual is eliminated with the aim of eliminating the double-difference ionosphere delay error residual, and constructing an integer linear relation among three-frequency carrier phase integer ambiguities of B1, B2 and B3;

3-2, constructing an integer linear relation between B1 and B2 double-frequency carrier phase integer ambiguity according to an integrated double-difference carrier phase observation equation of three frequencies after double-difference ionosphere delay error residual errors are eliminated and with the aim of eliminating a B3 frequency carrier phase observation value and integer ambiguity;

3-3, constructing a linear relation between B1 and B3 double-frequency carrier phase integer ambiguities with the aim of eliminating a B2 frequency carrier phase observation value and integer ambiguities according to an integrated double-difference carrier phase observation equation of three frequencies after double-difference ionosphere delay error residual errors are eliminated;

step 4, obtaining an initial value of B1 double-difference carrier phase integer ambiguity according to B1 frequency carrier phase observation data received by a BDS reference station receiver, and setting a value range and a sampling interval of the B1 double-difference carrier phase integer ambiguity so as to obtain a B1 double-difference carrier phase integer ambiguity alternative value;

step 5, substituting the B1 double-difference carrier phase integer ambiguity candidate value into the integer linear relation between the B1 and the B2 double-frequency carrier phase integer ambiguity obtained in the step 3-2 to obtain the B1 and B2 double-difference carrier phase integer ambiguity candidate values meeting the integer linear relation, namely obtaining the B1 and B2 double-difference carrier phase integer ambiguity candidate value combination;

step 6, substituting the B1 double-difference carrier phase integer ambiguity candidate value into the integer linear relation between the B1 and the B3 double-frequency carrier phase integer ambiguity obtained in the step 3-3 to obtain the B1 and B3 double-difference carrier phase integer ambiguity candidate values meeting the integer linear relation, namely obtaining the B1 and B3 double-difference carrier phase integer ambiguity candidate value combination;

step 7, substituting the B1 and B2 double difference carrier phase integer ambiguity alternative value combination and the B1 and B3 double difference carrier phase integer ambiguity alternative value combination into an integer linear relation among B1, B2 and B3 three-frequency carrier phase integer ambiguities to obtain B1, B2 and B3 double difference carrier phase integer ambiguities meeting the integer linear relation, namely the final B1, B2 and B3 double difference carrier phase integer ambiguities;

step 8, calculating triple-frequency double-difference ionospheric delay error residuals on the BDS reference station according to the obtained final B1, B2 and B3 double-difference carrier phase whole-cycle ambiguities, and if the triple-frequency double-difference ionospheric delay error residuals meet the mutual relation, performing data broadcasting by taking the final B1, B2 and B3 double-difference carrier phase whole-cycle ambiguities as fixed set values; and calculating a three-frequency double-difference ionospheric delay error residual on the BDS reference station according to the carrier phase observation data after the first epoch of the BDS reference station, if the difference of the double-difference ionospheric delay error residual of the adjacent epoch on the BDS reference station is larger than a set threshold, returning to the step 1, and otherwise, performing data broadcasting by taking the final B1, B2 and B3 three-frequency double-difference carrier phase integer ambiguity as a fixed set value.

The double-difference carrier phase observation equation of the three frequencies in the step 2 is as follows:

the B1 frequency double difference carrier phase observation equation multiplied by a real number is as follows:

$K_1\·{\mathrm{LMD}}_1\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{R1}^S=K_1\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_R^S-{\mathrm{LMD}}_1\·\▿\mathrm{\Δ}{N}_{R1}^S+\▿\mathrm{\Δ}{\mathrm{Orb}}_R^S-\▿\mathrm{\Δ}{\mathrm{Ion}}_{R1}^S+\▿\mathrm{\Δ}{\mathrm{Trop}}_R^S)---\left(1\right)$

wherein, K₁Representing a real number, LMD₁A wavelength representing the phase of the BDS carrier of the B1 frequency;representing double difference operators, the symbols representing double difference combining between carrier-phase observations of two reference stations and two BDS satellites,a B1 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;ambiguity representing the B1 frequency carrier phase of the reference station R receiving the BDS satellite S;representing the geometric range of the reference station R receiving the BDS satellite S;representing the double-differenced satellite orbit error residual,representing a double-difference tropospheric delay error residual;representing the B1 frequency carrier phase double-difference ionospheric delay error residual;

the B2 frequency double difference carrier phase observation equation multiplied by a real number is as follows:

$K_2\·{\mathrm{LMD}}_2\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{R2}^S=K_2\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_R^S-{\mathrm{LMD}}_2\·\▿\mathrm{\Δ}{N}_{R12}^S+\▿\mathrm{\Δ}{\mathrm{Orb}}_R^S-\▿\mathrm{\Δ}{\mathrm{Ion}}_{R2}^S+\▿\mathrm{\Δ}{\mathrm{Trop}}_R^S)---\left(2\right)$

wherein, K₂Representing a real number, LMD₂A wavelength representing the phase of the BDS carrier of the B2 frequency;a B2 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;ambiguity representing the B2 frequency carrier phase of the reference station R receiving the BDS satellite S;representing the B2 frequency carrier phase double-difference ionospheric delay error residual;

the B3 frequency double difference carrier phase observation equation multiplied by a real number is as follows:

$K_3\·{\mathrm{LMD}}_3\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{R3}^S=K_3\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_R^S-{\mathrm{LMD}}_3\·\▿\mathrm{\Δ}{N}_{R3}^S+\▿\mathrm{\Δ}{\mathrm{Orb}}_R^S-\▿\mathrm{\Δ}{\mathrm{Ion}}_{R3}^S+\▿\mathrm{\Δ}{\mathrm{Trop}}_R^S)---\left(3\right)$

wherein, K₃Representing a real number, LMD₃A wavelength representing the phase of the BDS carrier of the B3 frequency;a B3 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;ambiguity representing the B3 frequency carrier phase of the reference station R receiving the BDS satellite S;representing the B3 frequency carrier phase double-difference ionospheric delay error residual;

adding and integrating the double-difference carrier phase observation equations of the three frequencies to obtain the following formula:

wherein,

$l_{123}=(K_1+K_2+K_3)\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_R^S+\▿\mathrm{\Δ}{\mathrm{Orb}}_R^S+\▿\mathrm{\Δ}{\mathrm{Trop}}_R^S),$

$d_{123}=K_1\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{R1}^S+K_2\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{R2}^S+K_3\·\▿\mathrm{\Δ}{\mathrm{Trop}}_{R3}^S.$

constructing linear relations among B1, B2 and B3 three-frequency carrier phase integer ambiguity according to the step 3-1, which comprises the following steps:

3-1-1, substituting the double-difference ionospheric delay error residual errors into a double-difference carrier phase observation equation of three frequencies after addition and arrangement according to the relation among double-difference ionospheric delay error residual errors borne by the double-difference carrier phase observation values B1, B2 and B3;

the relation among double-difference ionospheric delay error residuals borne by the B1, B2 and B3 double-difference carrier phase observed values is as follows:

$\▿\mathrm{\Δ}{\mathrm{Ion}}_{R2}^S=\frac{f_1^2}{f_2^2}\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{R1}^S---\left(5\right)$

wherein,representing the B1 frequency carrier phase double-difference ionospheric delay error residual;representing the B2 frequency carrier phase double-difference ionospheric delay error residual; f. of₁B1 frequency, f, for BDS carrier phase₂B2 frequency, which is the BDS carrier phase;

$\▿\mathrm{\Δ}{\mathrm{Ion}}_{R3}^S=\frac{f_1^2}{f_3^2}\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{R1}^S---\left(6\right)$

wherein,representing the B1 frequency carrier phase double-difference ionospheric delay error residual;representing the B3 frequency carrier phase double-difference ionospheric delay error residual; f. of₁B1 frequency, f, for BDS carrier phase₃B3 frequency, which is the BDS carrier phase;

the double-difference ionospheric delay error residual of the double-difference carrier-phase observation value of B1 is used for representing the double-difference ionospheric delay error residual of the double-difference carrier-phase observation value of B2 and B3, and the double-difference ionospheric delay error residual is substituted into a double-difference carrier-phase observation equation of three frequencies after addition arrangement, so that the following formula is obtained:

$d_{123}=K_1\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{R1}^S+K_2\·\frac{f_1^2}{f_2^2}\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{R1}^S+K_3\·\frac{f_1^2}{f_3^2}\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{R1}^S---\left(7\right)$

wherein, K₁、K₂、K₃Representing real numbers, equation (7) being integratedThe double-difference ionosphere delay error residual in the integrated double-difference carrier phase observation equation of the three latter frequencies;

3-1-2, eliminating double-difference ionosphere delay error residual error, namely setting

3-1-3, arranging the double-difference carrier phase observation equation of the three frequencies after eliminating the double-difference ionosphere delay error residue, namely obtaining integer linear relations among the ambiguity of the B1, B2 and B3 three-frequency carrier phase whole-cycle;

the integer linear relation among B1, B2 and B3 three-frequency carrier phase integer ambiguity is as follows:

wherein,ambiguity representing the B1 frequency carrier phase of the reference station R receiving the BDS satellite S;ambiguity representing the B2 frequency carrier phase of the reference station R receiving the BDS satellite S;ambiguity representing the B3 frequency carrier phase of the reference station R receiving the BDS satellite S;c is the speed of light in vacuum;

a B1 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;a B2 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;a B3 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;

$l_{123}=(K_1+K_2+K_3)\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_R^S+\▿\mathrm{\Δ}{\mathrm{Orb}}_R^S+\▿\mathrm{\Δ}{\mathrm{Trop}}_R^S),$ representing the geometric range of the reference station R receiving the BDS satellite S;representing the double-differenced satellite orbit error residual,representing a double difference tropospheric delay error residual.

Constructing an integer linear relationship between B1 and B2 double-frequency carrier phase integer cycle ambiguities, which is specifically as follows, in the step 3-2:

step 3-2-1, eliminating observed values and integer ambiguity of B3 frequency carrier phase, and settingK₃Is equal to 0, i.e $K_1+K_2\·\frac{f_1^2}{f_2^2}+K_3\·\frac{f_1^2}{f_3^2}=0;$

Wherein f is₁B1 frequency, f, for BDS carrier phase₂B2 frequency, which is the BDS carrier phase; f. of₃B3 frequency, which is the BDS carrier phase; k₁、K₂、K₃Represents a real number;

step 3-2-2, according to the set value in the step 3-2-1, arranging a double-difference carrier phase observation equation of three frequencies to obtain integer linear relations between double-frequency carrier phase integer ambiguities of B1 and B2;

the integer linear relation between B1 and B2 double-frequency carrier phase integer ambiguity is as follows:

$\mathrm{\Δ}{N}_{R2}^S=-\frac{K_1\·f_2}{K_2\·f_1}\·\▿\mathrm{\Δ}{N}_{R1}^S-\frac{K_1\·f_2}{K_2\·f_1}\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{R1}^S-\▿\mathrm{\Δ}{\mathrm{\Φ}}_{R2}^S+\frac{(K_1+K_2)}{K_2\·{\mathrm{LMD}}_2}\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_R^S+\▿\mathrm{\Δ}{\mathrm{Orb}}_R^S+\▿\mathrm{\Δ}{\mathrm{Trop}}_R^S)---\left(9\right)$

wherein,ambiguity representing the B1 frequency carrier phase of the reference station R receiving the BDS satellite S;ambiguity representing the B2 frequency carrier phase of the reference station R receiving the BDS satellite S;c is the speed of light in vacuum;a B1 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;a B2 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;representing the geometric range of the reference station R receiving the BDS satellite S;representing the double-differenced satellite orbit error residual,representing a double difference tropospheric delay error residual.

Constructing an integer linear relationship between B1 and B3 double-frequency carrier phase integer cycle ambiguities in the step 3-3, which is specifically as follows:

step 3-3-1, eliminating observed values and integer ambiguity of B2 frequency carrier phase, and settingK₂Is equal to 0, i.e $K_1+K_2\·\frac{f_1^2}{f_2^2}+K_3\·\frac{f_1^2}{f_3^2}=0;$

Wherein f is₁B1 frequency, f, for BDS carrier phase₂B2 frequency, which is the BDS carrier phase; f. of₃B3 frequency, which is the BDS carrier phase; k₁、K₂、K₃Represents a real number;

3-3-2, arranging a double-difference carrier phase observation equation of three frequencies according to the set value in the step 3-3-1, and obtaining an integer linear relation between double-frequency carrier phase integer ambiguities of B1 and B3;

the integer linear relation between B1 and B3 double-frequency carrier phase integer ambiguity is as follows:

$\mathrm{\Δ}{N}_{R3}^S=-\frac{K_1\·f_3}{K_3\·f_1}\·\▿\mathrm{\Δ}{N}_{R1}^S-\frac{K_1\·f_3}{K_3\·f_1}\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{R1}^S-\▿\mathrm{\Δ}{\mathrm{\Φ}}_{R3}^S+\frac{(K_1+K_3)}{K_3\·{\mathrm{LMD}}_3}\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_R^S+\▿\mathrm{\Δ}{\mathrm{Orb}}_R^S+\▿\mathrm{\Δ}{\mathrm{Trop}}_R^S)---\left(10\right)$

wherein,ambiguity representing the B1 frequency carrier phase of the reference station R receiving the BDS satellite S;ambiguity representing the B3 frequency carrier phase of the reference station R receiving the BDS satellite S;c is the speed of light in vacuum;a B1 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;a B3 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;representing the geometric range of the reference station R receiving the BDS satellite S;representing the double-differenced satellite orbit error residual,representing a double difference tropospheric delay error residual.

The invention has the advantages that:

the invention provides a method for determining the integer ambiguity of a three-frequency carrier phase of a BDS reference station, which fully utilizes the special three-frequency carrier phase observation data of a BDS system and determines the integer ambiguity of a three-frequency carrier phase observation value of the BDS reference station by utilizing the integer linear relation among the integer ambiambiguities of the three-frequency carrier phase of the BDS, thereby realizing the accurate determination of the integer ambiguity of the network carrier phase of the BDS reference station; the method can determine the whole-cycle ambiguity of the three-frequency carrier phase of the BDS reference station by a single epoch, and can solve the problem that the BDS carrier phase whole-cycle ambiguity of the reference station network is not easily determined in real time and quickly due to slow change of the geometric configuration of the BDS observation satellite; meanwhile, the problem of cycle slip of the BDS reference station carrier phase observation data can be not considered, the work of detecting and processing the cycle slip of the observation data is avoided, and the workload of the BDS reference station network in the whole cycle ambiguity resolution is reduced; the BDS reference station network can be started in one epoch, and the reference station network provides error correction data of the BDS system at the fastest speed; the method uses a single double-difference satellite as an object to determine the integer ambiguity, does not need to solve a BDS reference station network carrier phase observation equation set, and enables the calculation amount of the BDS reference station network carrier phase integer ambiguity determination to be small.

Drawings

Fig. 1 is a flowchart of a method for determining an integer ambiguity of a tri-frequency carrier phase of a BDS reference station according to an embodiment of the present invention;

FIG. 2 is a schematic view of a reference station distribution according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a reference station A-B satellite C03-C07 double difference B1 frequency carrier phase ionospheric delay error residuals according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a reference station A-C satellite C03-C07 double difference B1 frequency carrier phase ionospheric delay error residuals according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a reference station B-C satellite C03-C07 double difference B1 frequency carrier phase ionospheric delay error residual error in accordance with an embodiment of the present invention;

FIG. 6 is a schematic diagram of a reference station A-B satellite C09-C07 double difference B1 frequency carrier phase ionospheric delay error residuals according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a reference station A-C satellite C09-C07 double difference B1 frequency carrier phase ionospheric delay error residuals according to an embodiment of the present invention;

FIG. 8 is a diagram of a reference station B-C satellite C09-C07 double difference B1 frequency carrier phase ionospheric delay error residual.

Detailed Description

An embodiment of the present invention will be further described with reference to the accompanying drawings.

A method for determining the integer ambiguity of the three-frequency carrier phase of a BDS reference station is disclosed, and a flow chart of the method is shown in figure 1, and comprises the following steps:

step 1, broadcasting tri-band carrier phase observation data to a BDS reference station receiver by each BDS satellite, and performing double-difference combination processing on the tri-band carrier phase observation data received by the BDS reference station receiver to eliminate clock difference of the BDS satellite and clock difference of the BDS reference station receiver and weaken troposphere delay error, ionosphere delay error and satellite orbit error in the BDS reference station observation data;

the BDS reference station receiver receives the observation data of the B1, B2 and B3 three-frequency carrier phases of the satellites; in the embodiment of the present invention, as shown in fig. 2, A, B, C indicates three reference stations; the three reference stations have latitude and longitude: a: latitude 31.28 °, longitude 114.62 °; b: latitude 30.82 °, longitude 114.80 °; c: latitude 30.58 °, longitude 114.00 °; the BDS reference station is erected in a wide visual field, and the quality of the receiver is good, so that the multipath effect and the observation noise of the observation data of the network carrier phase of the BDS reference station are small and negligible, and the original observation equation of the B1, B2 and B3 three-frequency carrier phase received by the BDS reference station receiver is as follows:

${\mathrm{LMD}}_1\·{\mathrm{\Φ}}_{R1}^S={\mathrm{\ρ}}_R^S+c\·(t_R-t^S)-{\mathrm{LMD}}_1\·N_{R1}^S+{\mathrm{Orb}}_R^S-{\mathrm{Ion}}_{R1}^S+{\mathrm{Trop}}_R^S---\left(11\right)$

${\mathrm{LMD}}_2\·{\mathrm{\Φ}}_{R2}^S={\mathrm{\ρ}}_R^S+c\·(t_R-t^S)-{\mathrm{LMD}}_2\·N_{R2}^S+{\mathrm{Orb}}_R^S-{\mathrm{Ion}}_{R2}^S+{\mathrm{Trop}}_R^S---\left(12\right)$

${\mathrm{LMD}}_3\·{\mathrm{\Φ}}_{R3}^S={\mathrm{\ρ}}_R^S+c\·(t_R-t^S)-{\mathrm{LMD}}_3\·N_{R3}^S+{\mathrm{Orb}}_R^S-{\mathrm{Ion}}_{R3}^S+{\mathrm{Trop}}_R^S---\left(13\right)$

in the formula, LMD₁0.19203m, LMD₂0.24834m, LMD₃0.23633 m;the coordinates accurately known by the reference station and the satellite coordinates provided by the BDS broadcast ephemeris are calculated; t is clock error in seconds, t_RFor reference station receiver clock error, t^SIs the satellite clock error of the BDS satellite;which is indicative of the satellite orbital error,representing tropospheric delay error;representing the B1 frequency ionospheric delay error;representing the B2 frequency ionospheric delay error;representing the B3 frequency ionospheric delay error;

the observation equations represented by equations (11), (12), (13) are the most basic observation equations of the raw observation data provided by the BDS reference station receiver; the method comprises the steps of determining the integer ambiguity of the double-difference BDS carrier phase; for the receivers of the two BDS reference stations A, B to receive the observation data broadcasted by the BDS satellites p and q, the four original observation equations of the two BDS satellites of the reference station A, B (as shown in fig. 2) with the same frequency p and q carrier phases can be double-difference combined to eliminate the clock difference of the BDS satellites and the clock difference of the BDS receiver of the reference station, and to attenuate the tropospheric delay error, ionospheric delay error, and satellite orbit error in the observation values, the following equations are provided:

${\mathrm{LMD}}_1\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}1}^{\mathrm{pq}}=\▿\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}-{\mathrm{LMD}}_1\·\▿\mathrm{\Δ}{N}_{\mathrm{AB}1}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Orb}}_{\mathrm{AB}}^{\mathrm{pq}}-\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}1}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}}^{\mathrm{pq}}---\left(14\right)$

${\mathrm{LMD}}_2\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}2}^{\mathrm{pq}}=\▿\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}-{\mathrm{LMD}}_2\·\▿\mathrm{\Δ}{N}_{\mathrm{AB}2}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Orb}}_{\mathrm{AB}}^{\mathrm{pq}}-\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}2}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}}^{\mathrm{pq}}---\left(15\right)$

${\mathrm{LMD}}_3\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}3}^{\mathrm{pq}}=\▿\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}-{\mathrm{LMD}}_3\·\▿\mathrm{\Δ}{N}_{\mathrm{AB}3}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Orb}}_{\mathrm{AB}}^{\mathrm{pq}}-\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}3}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}}^{\mathrm{pq}}---\left(16\right)$

wherein,is a double difference operator indicating that the symbol has been double-difference combined between the carrier-phase observations of the two BDS satellites p, q and the two reference stations A, B. Subscript A, B indicates reference station numbers, i.e., reference station a, reference station B, superscripts p, q indicating satellite p, satellite q;b1 frequency double difference carrier-phase observations representing satellites p, q at reference station A, B,presentation GinsengB2 frequency double difference carrier phase observations of satellites p, q at the test station A, B,b3 frequency double difference carrier-phase observations representing satellites p, q at reference station A, B,representing the range of the double-differenced satellite of satellites p and q at reference station A, B to the receiver,b1 frequency double difference carrier-phase integer ambiguities representing satellites p, q at reference station A, B,b2 frequency double difference carrier-phase integer ambiguities representing satellites p, q at reference station A, B,b3 frequency double difference carrier-phase integer ambiguities representing satellites p, q at reference station A, B,representing the double-differenced satellite orbit error residuals for satellites p, q at reference station A, B,b1 frequency double difference ionospheric delay error residuals representing satellites p, q at the reference station A, B,b2 frequency double difference ionospheric delay error residuals representing satellites p, q at the reference station A, B,b3 frequency double difference ionospheric delay error residuals representing satellites p, q at the reference station A, B,representing the double difference tropospheric delay error residuals for satellites p, q at reference station A, B.

Step 2, multiplying the triple-frequency carrier phase observation data subjected to double-difference combination processing by a real number to obtain a double-difference carrier phase observation equation of which three frequency carrier phase observation values contain real number coefficients, and adding and integrating the double-difference carrier phase observation equations of the three frequencies to obtain an integrated double-difference carrier phase observation equation of the three frequencies after integration;

multiplying the observed values of the carrier phases of B1, B2 and B3 of the satellites p and q at the BDS reference station A, B by a real number respectively, the following equations (1), (2) and (3) can be obtained:

$K_1\·{\mathrm{LMD}}_1\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}1}^{\mathrm{pq}}=K_1\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}-{\mathrm{LMD}}_1\·\▿\mathrm{\Δ}{N}_{\mathrm{AB}1}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Orb}}_{\mathrm{AB}}^{\mathrm{pq}}-\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}1}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}}^{\mathrm{pq}})---\left(1\right)$

$K_2\·{\mathrm{LMD}}_2\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}2}^{\mathrm{pq}}=K_2\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}-{\mathrm{LMD}}_2\·\▿\mathrm{\Δ}{N}_{\mathrm{AB}2}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Orb}}_{\mathrm{AB}}^{\mathrm{pq}}-\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}2}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}}^{\mathrm{pq}})$

$\left(2\right)$

$K_3\·{\mathrm{LMD}}_3\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}3}^{\mathrm{pq}}=K_3\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}-{\mathrm{LMD}}_3\·\▿\mathrm{\Δ}{N}_{\mathrm{AB}3}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Orb}}_{\mathrm{AB}}^{\mathrm{pq}}-\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}3}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}}^{\mathrm{pq}})---\left(3\right)$

wherein, K₁、K₂、K₃The real number is a coefficient of observed values of B1, B2, and B3 double-difference carrier phases.

The three frequency double-difference carrier phase observation equations (1), (2) and (3) of the satellites p and q at the BDS reference station A, B are subjected to addition integration processing to obtain the following equations:

wherein,

$l_{123}=(K_1+K_2+K_3)\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Orb}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}}^{\mathrm{pq}}),$

$d_{123}=K_1\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}1}^{\mathrm{pq}}+K_2\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}2}^{\mathrm{pq}}+K_3\·\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}3}^{\mathrm{pq}}.$

step 3, according to the integrated double-difference carrier phase observation equation of the three frequencies after integration, the mutual integer linear relationship between the B1, B2 and B3 carrier phase integer ambiguities of the three frequencies p and q on the BDS reference station A, B specifically includes:

in the embodiment of the invention, according to the formula (4), the observed values of the carrier phases of the B1, B2 and B3 of the satellites p and q on the BDS reference station A, B after double-difference combination are mainly the residual d of the ionospheric delay error subjected to double differences₁₂₃Double difference tropospheric delay error residualSum double difference satellite orbit error residualThe influence of (c).

Step 3-1, according to the integrated double-difference carrier phase observation equation of the three frequencies after integration and the double-difference ionosphere delay error residual relation borne by the B1, B2 and B3 double-difference carrier phase observation values, with the aim of eliminating the double-difference ionosphere delay error residual, obtaining the integrated double-difference carrier phase observation equation of the three frequencies after eliminating the double-difference ionosphere delay error residual, and obtaining the integer linear relation among the B1, B2 and B3 three-frequency carrier phase integer ambiguities of the satellites p and q on the BDS reference station A, B;

3-1-1, substituting the double-difference ionospheric delay error residual errors into a double-difference carrier phase observation equation of three frequencies after addition and arrangement according to the relation among double-difference ionospheric delay error residual errors borne by the double-difference carrier phase observation values B1, B2 and B3;

for formula (4), the troposphere delay error can eliminate most of the influence through the troposphere model provided by the prior art, and the main error influence is a double-difference ionosphere delay error residual error;

the ionospheric delay error residual relations of the B1, B2 and B3 double-difference carrier phase observed values of the satellites p and q at the BDS reference station A, B are respectively as follows: $\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}2}^{\mathrm{pq}}=\frac{f_1^2}{f_2^2}\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}1}^{\mathrm{pq}},\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}3}^{\mathrm{pq}}=\frac{f_1^2}{f_3^2}\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}1}^{\mathrm{pq}}.$

thus, for d in equation (4)₁₂₃Comprises the following steps:

$d_{123}=(K_1+K_2\·\frac{f_1^2}{f_2^2}+K_3\·\frac{f_1^2}{f_3^2})\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}1}^{\mathrm{pq}}---\left(17\right)$

3-1-2, eliminating double-difference ionosphere delay error residual error, namely setting

In the embodiment of the present invention, K is set₁＝1、 $K_2=-\frac{1}{2}\·\frac{f_2^2}{f_1^2},K_3=-\frac{1}{2}\·\frac{f_3^2}{f_1^2},$

Then: $K_1+K_2\·\frac{f_1^2}{f_2^2}+K_3\·\frac{f_1^2}{f_3^2}=1-\frac{1}{2}\·\frac{f_2^2}{f_1^2}\·\frac{f_1^2}{f_2^2}-\frac{1}{2}\·\frac{f_3^2}{f_1^2}\·\frac{f_1^2}{f_3^2}=0,$

comprises the following steps: $d_{123}=K_1\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}1}^{\mathrm{pq}}+K_2\·\frac{f_1^2}{f_2^2}\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}1}^{\mathrm{pq}}+K_3\·\frac{f_1^2}{f_3^2}\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}1}^{\mathrm{pq}}=0,$

namely: $d_{123}=K_1\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}1}^{\mathrm{pq}}+K_2\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}2}^{\mathrm{pq}}+K_3\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}3}^{\mathrm{pq}}=0;$

according to K above₁、K₂、K₃Setting value, the double-difference ionospheric delay error residual d in the formula (4) can be eliminated₁₂₃The influence of (c) can be obtained from equation (4):

wherein,

$l_{123}=(K_1+K_2+K_3)\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Orb}}_{\mathrm{AB}}^{\mathrm{pq}})$

3-1-3, arranging the double-difference carrier phase observation equation of the three frequencies after eliminating the double-difference ionosphere delay error residue, namely obtaining integer linear relations among the ambiguity of the B1, B2 and B3 three-frequency carrier phase whole-cycle;

further elaboration from equation (18) yields equations (19), (20):

wherein the wavelength ${\mathrm{LMD}}_1=\frac{c}{f_1},{\mathrm{LMD}}_2=\frac{c}{f_2},{\mathrm{LMD}}_3=\frac{c}{f_3},$ From this, equation (21) can be derived:

equation (21) is the integer linear relationship between B1, B2, and B3 three-frequency carrier-phase integer ambiguities.

Step 3-2, constructing an integer linear relationship between B1 and B2 double-frequency carrier phase integer ambiguities of satellites p and q on a BDS reference station A, B according to an integrated double-difference carrier phase observation equation of three frequencies after double-difference ionosphere delay error residual is eliminated and with the aim of eliminating a B3 frequency carrier phase observation value and an integer ambiguity, and specifically comprising the following steps:

step 3-2-1, eliminating observed values and integer ambiguity of B3 frequency carrier phase, and settingK₃Is equal to 0, i.e $K_1+K_2\·\frac{f_1^2}{f_2^2}+K_3\·\frac{f_1^2}{f_3^2}=0;$

In the embodiment of the invention, K is set according to the formula (18)₁＝1、K₃For formula (17), then, there is 0 $1-\frac{f_2^2}{f_1^2}\·\frac{f_1^2}{f_2^2}+0\·\frac{f_1^2}{f_3^2}=0,$ Namely, it is $K_1+K_2\·\frac{f_1^2}{f_2^2}+K_3\·\frac{f_1^2}{f_3^2}=0,$ If the formula (18) does not have the observed value of the carrier phase of B3 and the integer ambiguity, and only the observed values of the carrier phases of B1 and B2 and the integer ambiguity can obtain the integer linear relation of the integer ambiguity of the carrier phases of B1 and B2;

step 3-2-2, according to the set value in the step 3-2-1, arranging a double-difference carrier phase observation equation of three frequencies to obtain integer linear relations between double-frequency carrier phase integer ambiguities of B1 and B2;

for d in equation (4)₁₂₃Namely, the following steps are provided: $d_{123}=\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}1}^{\mathrm{pq}}-\frac{f_2^2}{f_1^2}\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}2}^{\mathrm{pq}}+0\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}3}^{\mathrm{pq}}=0.$

that is, for equation (4), the double-differenced ionospheric delay error residual d in the B1, B2 carrier-phase observations of the satellites p, q at the BDS reference station A, B can be eliminated₁₂₃The impact, then, is:

$\begin{array}{c}{\mathrm{LMD}}_1\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}1}^{\mathrm{pq}}-\frac{f_2^2}{f_1^2}\·{\mathrm{LMD}}_2\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}2}^{\mathrm{pq}}\\ =(1-\frac{f_2^2}{f_1^2})\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Orb}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}}^{\mathrm{pq}})-{\mathrm{LMD}}_1\·\▿\mathrm{\Δ}{N}_{\mathrm{AB}1}^{\mathrm{pq}}+\frac{f_2^2}{f_1^2}\·{\mathrm{LMD}}_2\·\▿\mathrm{\Δ}{N}_{\mathrm{AB}2}^{\mathrm{pq}}\end{array}---\left(22\right)$

further finishing to obtain:

$\begin{array}{c}\▿\mathrm{\Δ}{N}_{\mathrm{AB}2}^{\mathrm{pq}}=\frac{f_1^2\·{\mathrm{LMD}}_1}{f_2^2\·{\mathrm{LMD}}_2}\·\▿\mathrm{\Δ}{N}_{\mathrm{AB}1}^{\mathrm{pq}}+\frac{f_1^2\·{\mathrm{LMD}}_1}{f_2^2\·{\mathrm{LMD}}_2}\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}1}^{\mathrm{pq}}-\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}2}^{\mathrm{pq}}\\ -\frac{(f_1^2-f_2^2)}{f_2^2\·{\mathrm{LMD}}_2}\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Orb}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}}^{\mathrm{pq}})\end{array}---\left(23\right)$

wherein the wavelength ${\mathrm{LMD}}_1=\frac{c}{f_1},{\mathrm{LMD}}_2=\frac{c}{f_2};$

Then equation (23) has:

$\▿\mathrm{\Δ}{N}_{\mathrm{AB}2}^{\mathrm{pq}}=\frac{f_1}{f_2}\·\▿\mathrm{\Δ}{N}_{\mathrm{AB}1}^{\mathrm{pq}}+\frac{f_1}{f_2}\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}1}^{\mathrm{pq}}-\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}2}^{\mathrm{pq}}-\frac{(f_1^2-f_2^2)}{f_2^2\·{\mathrm{LMD}}_2}\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Orb}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}}^{\mathrm{pq}})---\left(24\right)$

equation (24) is an integer linear relationship between B1 frequency and B2 frequency carrier-phase integer ambiguities.

3-3, constructing an integer linear relationship between B1 and B3 double-frequency carrier phase integer ambiguities of the satellites p and q on the BDS reference station A, B according to an integrated double-difference carrier phase observation equation of the three frequencies after double-difference ionosphere delay error residual errors are eliminated and with the aim of eliminating a B2 frequency carrier phase observation value and an integer ambiguity, and specifically comprising the following steps:

step 3-3-1, eliminating observed values and integer ambiguity of B2 frequency carrier phase, and settingNamely, it is $K_1+K_2\·\frac{f_1^2}{f_2^2}+K_3\·\frac{f_1^2}{f_3^2}=0;$

In the embodiment of the present invention, K1 is set to 1,K2 is 0, and for formula (17), there is $1+0\·\frac{f_1^2}{f_2^2}-\frac{f_3^2}{f_1^2}\·\frac{f_1^2}{f_3^2}=0,$ Namely, it is $K_1+K_2\·\frac{f_1^2}{f_2^2}+K_3\·\frac{f_1^2}{f_3^2}=0.$ That is, in the formula (18), the B2 carrier phase observation value and the integer ambiguity are not present, and only the B1 and B3 carrier phase observation values and the integer ambiguity are present, so that the integer linear relationship of the B1 and B3 carrier phase integer ambiguity can be obtained.

3-3-2, arranging a double-difference carrier phase observation equation of three frequencies according to the set value in the step 3-3-1, and obtaining an integer linear relation between double-frequency carrier phase integer ambiguities of B1 and B3;

for d in equation (4)₁₂₃Namely, the following steps are provided: $d_{123}=\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}1}^{\mathrm{pq}}+0\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}2}^{\mathrm{pq}}-\frac{f_3^2}{f_1^2}\·\▿\mathrm{\Δ}{\mathrm{Ion}}_{\mathrm{AB}3}^{\mathrm{pq}}=0.$

that is, for equation (4), the double-differenced ionospheric delay error residual d in the B1, B3 carrier-phase observations of the satellites p, q at the BDS reference station A, B can be eliminated₁₂₃The impact, then, is:

$\begin{array}{c}{\mathrm{LMD}}_1\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}1}^{\mathrm{pq}}-\frac{f_3^2}{f_1^2}\·{\mathrm{LMD}}_3\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}3}^{\mathrm{pq}}\\ =(1-\frac{f_3^2}{f_1^2})\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Orb}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}}^{\mathrm{pq}})-{\mathrm{LMD}}_1\·\▿\mathrm{\Δ}{N}_{\mathrm{AB}1}^{\mathrm{pq}}+\frac{f_3^2}{f_1^2}\·{\mathrm{LMD}}_3\·\▿\mathrm{\Δ}{N}_{\mathrm{AB}3}^{\mathrm{pq}}\end{array}---\left(25\right)$

further finishing to obtain:

$\begin{array}{c}\▿\mathrm{\Δ}{N}_{\mathrm{AB}3}^{\mathrm{pq}}=\frac{f_1^2\·{\mathrm{LMD}}_1}{f_3^2\·{\mathrm{LMD}}_3}\·\▿\mathrm{\Δ}{N}_{\mathrm{AB}1}^{\mathrm{pq}}+\frac{f_1^2\·{\mathrm{LMD}}_1}{f_3^2\·{\mathrm{LMD}}_3}\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}1}^{\mathrm{pq}}-\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}3}^{\mathrm{pq}}\\ -\frac{(f_1^2-f_3^2)}{f_3^2\·{\mathrm{LMD}}_3}\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Orb}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}}^{\mathrm{pq}})\end{array}---\left(26\right)$

wherein the wavelength ${\mathrm{LMD}}_1=\frac{c}{f_1},{\mathrm{LMD}}_3=\frac{c}{f_3};$

Then equation (26) has:

$\▿\mathrm{\Δ}{N}_{\mathrm{AB}3}^{\mathrm{pq}}=\frac{f_1}{f_3}\·\▿\mathrm{\Δ}{N}_{\mathrm{AB}1}^{\mathrm{pq}}+\frac{f_1}{f_3}\·\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}1}^{\mathrm{pq}}-\▿\mathrm{\Δ}{\mathrm{\Φ}}_{\mathrm{AB}3}^{\mathrm{pq}}-\frac{(f_1^2-f_3^2)}{f_3^2\·{\mathrm{LMD}}_3}\·(\▿\mathrm{\Δ}{\mathrm{\ρ}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Orb}}_{\mathrm{AB}}^{\mathrm{pq}}+\▿\mathrm{\Δ}{\mathrm{Trop}}_{\mathrm{AB}}^{\mathrm{pq}})---\left(27\right)$

equation (27) is the integer linear relationship between the B1 frequency and the B3 frequency carrier-phase integer ambiguity.

Step 4, obtaining an initial value of B1 double-difference carrier phase integer ambiguity according to B1 frequency carrier phase observation data received by a BDS reference station receiver, and setting a value range and a sampling interval of the B1 double-difference carrier phase integer ambiguity so as to obtain a B1 double-difference carrier phase integer ambiguity alternative value;

in the embodiment of the invention, the alternative values of the B1 and B2 carrier phase integer ambiguity are selected through an integer linear relation formula (24) of the B1 and B2 carrier phase integer ambiguity of the satellites p and q on the BDS reference station A, B in the step 3-2; the B1, B3 carrier phase integer ambiguity alternative values are selected by the integer linear relationship equation (27) for the B1, B3 carrier phase integer ambiguities for the satellites p, q at the BDS reference station A, B in step 3-3.

In the embodiment of the invention, the B1 double-difference carrier phase integer ambiguity is calculated by the formula (14)At an initial value of (2) in obtainingAfter the initial value of (a), selecting an alternative value of B1 double-difference carrier phase integer ambiguity at a certain range around the initial value according to a one-week interval, wherein the selected range is based on the double-difference observation error residual error in the formula (14). Under normal observation conditions, underThe selected B1 double-difference carrier phase integer ambiguity value can meet the requirement within the range of about 40 weeks.

Step 5, substituting the B1 double-difference carrier phase integer ambiguity candidate value into an integer linear relation between B1 and B2 double-frequency carrier phase integer ambiambiguity to obtain B1 and B2 double-difference carrier phase integer ambiguity candidate values meeting the integer linear relation, namely obtaining a B1 and B2 double-difference carrier phase integer ambiguity candidate value combination;

in the embodiment of the invention, the method for selecting the linear relation satisfying the integral linear relation constraint of the formula (24) according to the formula (24)Integer ambiguity candidate value. The selected B1 and B2 double-difference carrier-phase integer ambiguity alternative values are constrained by the formula (24), and specifically include:

for in equation (24)Coefficient of (2)Whether f or not₁、f₂Is what is the numerical value of (a), real numberCan be described as a fractionNamely, the method comprises the following steps:

$\frac{A_1^{\′}}{A_2^{\′}}=\frac{f_1}{f_2}---\left(28\right)$

wherein A'₁、A′₂Are all integers.

In the embodiment of the present invention, since the phase frequencies of the B1 and B2 carriers of the BDS are respectively: 1561.098Mhz and 1207.14Mhz, therefore,namely A'₁＝763、A′₂＝590。

For equation (24), in the current epoch, the double-difference carrier-phase observations thereinGeometric distance of satellite to receiverResidual error of double-differenced satellite orbit error and tropospheric delay errorIs a constant term. Wavelength LMD of B2 carrier phase₂B1 carrier phase frequency f₁B2 carrier phase frequency f₂Which is itself a fixed constant. Therefore, the key factor in determining the variation of the B1 double difference carrier-phase integer ambiguity candidate and the B2 double difference carrier-phase integer ambiguity candidate isCoefficient of (2)The coefficients are related to the B1, B2 carrier phase frequencies of the BDS, independent of the satellite and reference stations. So any two pairs for any two BDS reference stationsA difference satellite having a fixed B1 double difference carrier-phase integer ambiguity coefficient in the integer linear relationship between the B1 double difference carrier-phase integer ambiguity and the B2 double difference carrier-phase integer ambiguity

The B1 frequency double difference carrier phase integer ambiguity alternative value and the B2 double difference carrier phase integer ambiguity alternative value satisfying the integer linear relation constraint of the formula (24) according to the fractionThe denominator and the integer value of the numerator of (a) change. Namely, the B1 double-difference carrier phase integer ambiguity alternative value is changed according to 590, and the B2 double-difference carrier phase integer ambiguity alternative value is changed according to 763; according to the change rule, selecting B1 and B2 double difference carrier phase integer ambiguity alternative values through a formula (24), wherein the integer ambiguity alternative values are changed at intervals; since the formula (24) also includes some error residuals and observation model residuals, the interval between the B1 and B2 double difference carrier phase integer ambiguity candidates is not exactly equal to 590 and 763, and generally satisfies the formula (24) that the fraction value and the fraction of the interval between the B1 and B2 double difference carrier phase integer ambiguity candidates areThe numerical values are relatively close; b1 and B2 double difference carrier phase integer ambiguity alternative values are changed at intervals, so that B1 and B2 carrier phase integer ambiguities are easy to determine; the larger the numerical interval of the alternative values of the B1 and B2 double-difference carrier phase integer ambiguity is, the more easily the correct and wrong alternative values of the carrier phase integer ambiguity can be distinguished, and the more favorable the determination of the carrier phase integer ambiguity is.

Step 6, substituting the B1 double-difference carrier phase integer ambiguity candidate value into an integer linear relation between B1 and B3 double-frequency carrier phase integer ambiambiguity to obtain B1 and B3 double-difference carrier phase integer ambiguity candidate values meeting the integer linear relation, namely obtaining a B1 and B3 double-difference carrier phase integer ambiguity candidate value combination;

using the B1 double difference carrier phase integer ambiguity calculated in step 4The initial value and the alternative value of (2) are selected according to the formula (27) to satisfy the integer linear relationshipInteger ambiguity candidate value. The selected B1 and B3 carrier phase integer ambiguity alternative values are constrained by the formula (27), and specifically include:

for in equation (27)Coefficient of (2)Whether f or not₁、f₃Is what is the numerical value of (a), real numberCan be described as a fractionNamely, the method comprises the following steps:

$\frac{A_1^{\′}}{A_3^{\′}}=\frac{f_1}{f_3}---\left(29\right)$

wherein A'₁、A′₃Are all integers.

Since the frequencies of the B1 and B3 carrier phases of the BDS are: 1561.098Mhz and 1268.52Mhz,namely A'₁＝763、A′₃＝620。

For equation (27), in the current epoch, the double-difference carrier-phase observations thereinGeometric distance of satellite to receiverResidual error of double-differenced satellite orbit error and tropospheric delay errorIs a constant term. Wavelength LMD of B3 carrier phase₃B1 carrier phase frequency f₁B3 carrier phase frequency f₃Which is itself a fixed constant. Therefore, the key factor in determining the variation of the B1 double difference carrier-phase integer ambiguity candidate and the B3 double difference carrier-phase integer ambiguity candidate isCoefficient of (2)The coefficients are related to the B1, B3 carrier phase frequencies of the BDS, independent of the satellite and reference stations. Therefore, for any two double-differenced satellites of any two BDS reference stations, the coefficient of the B1 double-differenced carrier-phase integer ambiguity in the integer linear relationship between the B1 double-differenced carrier-phase integer ambiguity and the B3 double-differenced carrier-phase integer ambiguity is fixed as

The B1 frequency double difference carrier phase integer ambiguity alternative value and the B3 double difference carrier phase integer ambiguity alternative value satisfying the integer linear relation constraint of formula (27) according to fractionThe denominator and the integer value of the numerator of (a) change. That is, the B1 double difference carrier phase integer ambiguity candidate changes according to 620, and the B3 double difference carrier phase integer ambiguity candidate changes according to 763. According to the change rule, B1 and B3 double difference carrier phase integer ambiguity alternative values are selected through formula (27), and the integer ambiguity alternative values are changed at intervals. Since the formula (27) also contains some error residuals and observation model residuals, the interval between the B1 and B3 double difference carrier phase integer ambiguity candidates is not strictly equal to 620 and 763, and the fractional values of the interval components between the B1 and B3 double difference carrier phase integer ambiguity candidates generally satisfy the formula (27)The values are closer. The B1 and B3 double difference carrier phase integer ambiguities are easily determined by the interval change of the B1 and B3 double difference carrier phase integer ambiguities alternative values. The larger the numerical interval of the alternative values of the B1 and B3 double-difference carrier phase integer ambiguity is, the more easily the correct and wrong alternative values of the carrier phase integer ambiguity can be distinguished, and the more favorable the determination of the carrier phase integer ambiguity is.

Step 7, substituting the B1 and B2 double difference carrier phase integer ambiguity alternative value combination and the B1 and B3 double difference carrier phase integer ambiguity alternative value combination into an integer linear relation among B1, B2 and B3 three-frequency carrier phase integer ambiguities to obtain B1, B2 and B3 double difference carrier phase integer ambiguities meeting the integer linear relation, namely the final B1, B2 and B3 double difference carrier phase integer ambiguities;

in the embodiment of the invention, the step 5 and the step 6 are based on the formulas (24), (27) and B1 double difference carrier phase integer ambiguityB2 double difference carrier phase integer ambiguity is selectedAnd B3 double difference carrier-phase integer ambiguityAn alternative value of (a). The selected alternative values of the B1, B2 and B3 double difference carrier phase integer ambiguity of the satellites p and q at the reference station A, B have respective value interval changes, and the existence of the value intervals increases the accuracy of the fixation of the three-frequency carrier phase integer ambiguity. The double difference carrier-phase integer ambiguities of the B1, B2, and B3 of the satellites p and q at the reference station A, B are then determined by the integer linear relationship of the tri-band carrier-phase integer ambiguities of the satellites p and q at the BDS reference station A, B.

In the embodiment of the invention, B1 double difference carrier phase integer ambiguityAccording to B2 double difference carrier phase integer ambiguity selected by equation (24)And B3 double difference carrier phase integer ambiguity according to equation (27)The alternative values of (a) are unified. Namely, the same B1 double-difference carrier phase integer ambiguity alternative value and the corresponding B2 and B3 double-difference carrier phase integer ambiguity alternative value form a three-frequency double-difference carrier phase integer ambiguity alternative combination.

For in equation (21)Coefficient of (2) Coefficient of (2)Whether f or not₁、f₂、f₃What is the value of (c) is,the numerical values of (A) can describe the number of componentsTo express that there are:

$\frac{B_1^{\′}}{B_3^{\′}}=\frac{2\·f_1}{f_3}---\left(30\right)$

$\frac{C_2^{\′}}{C_3^{\′}}=\frac{f_2}{f_3}---\left(31\right)$

and (3) obtaining a formula (32) by arranging the formula (21):

wherein, B'₁、B′₃、C′₂、C′₃Are integers. Since the frequencies of the B1, B2, and B3 carrier phases of the BDS are: 1561.098Mhz, 1207.14Mhz, 1268.52 Mhz. Therefore, the first and second electrodes are formed on the substrate,namely B'₁＝763、B′₃＝310、C′₂＝59、C′₃＝62。

For equation (32), in the current epoch, l therein₁₂₃、Frequency f of B1 carrier phase being a constant term₁B2 carrier phase frequency f₂B3 carrier phase frequency f₃、LMD₃Which is itself a fixed constant. Therefore, the key factor of the linear relation between the B1 and B2 double difference carrier-phase integer ambiguity and the B3 double difference carrier-phase integer ambiguity isCoefficient of (2)Andcoefficient of (2)The two coefficients are related to the B1, B2, B3 carrier phase frequencies of the BDS, and are independent of the satellite and reference stations. Therefore, for any two double-difference satellites of any two BDS reference stations, the coefficients of B1 and B2 double-difference carrier-phase integer ambiguity in the integer linear relation of B1, B2 and B3 triple-frequency double-difference carrier-phase integer ambiguity are fixed $\frac{B_1^{\′}}{B_3^{\′}}=\frac{763}{310},\frac{C_2^{\′}}{C_3^{\′}}=\frac{59}{62}.$

The B1, B2, B3 tri-band double difference carrier phase integer ambiguities of the satellites p, q at the reference station A, B must satisfy equation (32). That is, the wrong candidate values for B1, B2, and B3 double difference carrier phase integer ambiguities do not satisfy the requirement of equation (32), and the correct candidate values for B1, B2, and B3 double difference carrier phase integer ambiguities satisfy the linear relationship between the three frequency integer ambiguities of equation (32).

Alternative combinations of the B1, B2, and B3 double difference carrier-phase integer ambiguities are substituted into equation (32). Among the B1, B2, and B3 tri-band double difference carrier phase integer ambiguity alternative combinations satisfying the integer linear relationship of formula (24) and formula (27), only the correct ambiguity alternative combination satisfies the tri-band integer ambiguity linear relationship of formula (32). The correct B1, B2, B3 tri-band double difference carrier phase integer ambiguity can be determined.

Since the B1, B2 double difference carrier phase integer ambiguity candidate is selected by equation (24) and the B1, B3 double difference carrier phase integer ambiguity candidate is selected by equation (27), there are variations and intervals between these integer ambiguity candidates. Therefore, the integer linear relationship between the formula (24) and the formula (27) is satisfied numerically, and only one combined three-frequency integer ambiguity alternative value satisfies the linear relationship of the formula (32) within a certain range of the B1 double-difference carrier-phase integer ambiguity initial value.

Step 8, calculating triple-frequency double-difference ionospheric delay error residuals on the BDS reference station according to the obtained final B1, B2 and B3 double-difference carrier phase whole-cycle ambiguities, and if the triple-frequency double-difference ionospheric delay error residuals meet the mutual relation, performing data broadcasting by taking the final B1, B2 and B3 double-difference carrier phase whole-cycle ambiguities as fixed set values; and calculating a three-frequency double-difference ionospheric delay error residual on the BDS reference station according to the carrier phase observation data after the first epoch of the BDS reference station, if the difference of the double-difference ionospheric delay error residual of the adjacent epoch on the BDS reference station is larger than a set threshold, returning to the step 1, and otherwise, performing data broadcasting by taking the final B1, B2 and B3 three-frequency double-difference carrier phase integer ambiguity as a fixed set value.

In the embodiment of the invention, after B1, B2 and B3 carrier phase whole-cycle ambiguities of satellites p and q on a BDS reference station A, B are determined, ionospheric delay error residuals of double-difference satellites are calculated. Because the GEO satellite in the BDS system is unchanged relative to the earth position, the motion period of the IGSO satellite is long, and the signal propagation path of the GEO satellite of the BDS reference station network is basically unchanged, the double-difference ionosphere delay error residual of the GEO satellite and the IGSO satellite of the BDS system is relatively stable. The whole-cycle ambiguity determination result can be checked through the correlation of the ionospheric delay error residuals of all the BDS satellites on the same reference station, and the success rate of whole-cycle ambiguity single epoch determination of the BDS reference station network is guaranteed. And the double-difference ionosphere delay error residual between the epochs is utilized to carry out the test of the single-epoch integer ambiguity resolution result.

Fig. 3 to 5 are time sequences of B1 double-difference carrier phase ionospheric delay error residuals of satellites C03 to C07, which are obtained by calculating B1, B2, and B3 three-frequency carrier phase whole-cycle ambiguities after the B1, B2, and B3 three-frequency carrier phase whole-cycle ambiguities are correctly determined. Fig. 3 is a B1 double difference ionospheric delay error residual for reference station a and reference station B, fig. 4 is a B1 double difference ionospheric delay error residual for reference station a and reference station C, and fig. 5 is a B1 double difference ionospheric delay error residual for reference station B and reference station C. After the three-frequency carrier phase integer ambiguity is accurately determined, the correct B1 double-difference ionospheric delay error residuals can be obtained. The curve in the figure is the calculation result of the B1 double-difference ionospheric delay error residual after ambiguity determination, and it can be seen from the figure that the result change of the B1 double-difference ionospheric delay error residual between epochs is in centimeter level and accords with the correct change rule of the ionospheric delay error residual, that is, the whole-cycle ambiguity determination result is proved to be correct. And, the BDS reference station can realize the purpose of playing correct C03-C07 ionospheric error residual correction numbers of the satellite.

Fig. 6 to 8 are time sequences of B1 double-difference carrier phase ionospheric delay error residuals of satellites C09 to C07, which are obtained by calculating B1, B2, and B3 three-frequency carrier phase whole-cycle ambiguities after the B1, B2, and B3 three-frequency carrier phase whole-cycle ambiguities are correctly determined. Fig. 6 is a B1 double difference ionospheric delay error residual for reference station a and reference station B, fig. 7 is a B1 double difference ionospheric delay error residual for reference station a and reference station C, and fig. 8 is a B1 double difference ionospheric delay error residual for reference station B and reference station C. After the three-frequency carrier phase integer ambiguity is accurately determined, the correct B1 double-difference ionospheric delay error residuals can be obtained. The curve in the figure is the calculation result of the B1 double-difference ionospheric delay error residual after ambiguity determination, and it can be seen from the figure that the result change of the B1 double-difference ionospheric delay error residual between epochs is in centimeter level and accords with the correct change rule of the ionospheric delay error residual, that is, the whole-cycle ambiguity fixing result is proved to be correct. And, the BDS reference station can realize the purpose of playing correct ionospheric error residual correction numbers of the satellites C09-C07.

Claims (5)

1. A BDS reference station three-frequency carrier phase integer ambiguity determination method is characterized by comprising the following steps:

step 1, broadcasting tri-band carrier phase observation data to a BDS reference station receiver by each BDS satellite, and performing double-difference combination processing on the tri-band carrier phase observation data received by the BDS reference station receiver to eliminate clock difference of the BDS satellite and clock difference of the BDS reference station receiver and weaken troposphere delay error, ionosphere delay error and satellite orbit error in the BDS reference station observation data;

step 2, multiplying the triple-frequency carrier phase observation data subjected to double-difference combination processing by a real number to obtain a double-difference carrier phase observation equation of which three frequency carrier phase observation values contain real number coefficients, and adding and integrating the double-difference carrier phase observation equations of the three frequencies to obtain an integrated double-difference carrier phase observation equation of the three frequencies after integration;

step 3, constructing a mutual integer linear relation between three-frequency carrier phase integer ambiguities of the BDS reference station according to an integrated double-difference carrier phase observation equation of the three integrated frequencies, and specifically comprising the following steps:

3-1, according to the integrated double-difference carrier phase observation equation of the three frequencies after integration and the double-difference ionosphere delay error residual relation borne by the B1, B2 and B3 double-difference carrier phase observation values, obtaining the integrated double-difference carrier phase observation equation of the three frequencies after the double-difference ionosphere delay error residual is eliminated with the aim of eliminating the double-difference ionosphere delay error residual, and constructing an integer linear relation among three-frequency carrier phase integer ambiguities of B1, B2 and B3;

3-2, constructing an integer linear relation between B1 and B2 double-frequency carrier phase integer ambiguity according to an integrated double-difference carrier phase observation equation of three frequencies after double-difference ionosphere delay error residual errors are eliminated and with the aim of eliminating a B3 frequency carrier phase observation value and integer ambiguity;

3-3, constructing an integer linear relation between B1 and B3 double-frequency carrier phase integer ambiguity according to an integrated double-difference carrier phase observation equation of three frequencies after double-difference ionosphere delay error residual errors are eliminated and with the aim of eliminating a B2 frequency carrier phase observation value and integer ambiguity;

step 4, obtaining an initial value of B1 double-difference carrier phase integer ambiguity according to B1 frequency carrier phase observation data received by a BDS reference station receiver, and setting a value range and a sampling interval of the B1 double-difference carrier phase integer ambiguity so as to obtain a B1 double-difference carrier phase integer ambiguity alternative value;

step 5, substituting the B1 double-difference carrier phase integer ambiguity candidate value into the integer linear relation between the B1 and the B2 double-frequency carrier phase integer ambiguity obtained in the step 3-2 to obtain the B1 and B2 double-difference carrier phase integer ambiguity candidate values meeting the integer linear relation, namely obtaining the B1 and B2 double-difference carrier phase integer ambiguity candidate value combination;

step 6, substituting the B1 double-difference carrier phase integer ambiguity candidate value into the integer linear relation between the B1 and the B3 double-frequency carrier phase integer ambiguity obtained in the step 3-3 to obtain the B1 and B3 double-difference carrier phase integer ambiguity candidate values meeting the integer linear relation, namely obtaining the B1 and B3 double-difference carrier phase integer ambiguity candidate value combination;

step 7, substituting the B1 and B2 double difference carrier phase integer ambiguity alternative value combination and the B1 and B3 double difference carrier phase integer ambiguity alternative value combination into an integer linear relation among B1, B2 and B3 three-frequency carrier phase integer ambiguities to obtain B1, B2 and B3 double difference carrier phase integer ambiguities meeting the integer linear relation, namely the final B1, B2 and B3 double difference carrier phase integer ambiguities;

step 8, calculating triple-frequency double-difference ionospheric delay error residuals on the BDS reference station according to the obtained final B1, B2 and B3 double-difference carrier phase whole-cycle ambiguities, and if the triple-frequency double-difference ionospheric delay error residuals meet the mutual relation, performing data broadcasting by taking the final B1, B2 and B3 double-difference carrier phase whole-cycle ambiguities as fixed set values; and calculating a three-frequency double-difference ionospheric delay error residual on the BDS reference station according to the carrier phase observation data after the first epoch of the BDS reference station, if the difference of the double-difference ionospheric delay error residual of the adjacent epoch on the BDS reference station is larger than a set threshold, returning to the step 1, and otherwise, performing data broadcasting by taking the final B1, B2 and B3 three-frequency double-difference carrier phase integer ambiguity as a fixed set value.

2. The method for determining the ambiguity of the whole cycle of the three-frequency carrier phases of the BDS reference station as claimed in claim 1, wherein the equation of the observation of the double-difference carrier phases of the three frequencies in step 2 is as follows:

the B1 frequency double difference carrier phase observation equation multiplied by a real number is as follows:

$K_1\·{\mathrm{LMD}}_1\·\▿{\mathrm{\Δ\Φ}}_{R_1}^S=K_1\·(\▿{\mathrm{\Δ\ρ}}_R^S-{\mathrm{LMD}}_1\·\▿{\mathrm{\ΔN}}_{R_1}^S+\▿{\mathrm{\ΔOrb}}_R^S-\▿{\mathrm{\ΔIon}}_{R_1}^S+\▿{\mathrm{\ΔTrop}}_R^S)---\left(1\right)$

wherein, K₁Representing a real number, LMD₁A wavelength representing the phase of the BDS carrier of the B1 frequency;representing double difference operators, the symbols representing double difference combining between carrier-phase observations of two reference stations and two BDS satellites,a B1 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;ambiguity representing the B1 frequency carrier phase of the reference station R receiving the BDS satellite S;representing the geometric range of the reference station R receiving the BDS satellite S;representing the double-differenced satellite orbit error residual,representing a double-difference tropospheric delay error residual;representing the B1 frequency carrier phase double-difference ionospheric delay error residual;

the B2 frequency double difference carrier phase observation equation multiplied by a real number is as follows:

$K_2\·{\mathrm{LMD}}_2\·\▿{\mathrm{\Δ\Φ}}_{R_2}^S=K_2\·(\▿{\mathrm{\Δ\ρ}}_R^S-{\mathrm{LMD}}_2\·\▿{\mathrm{\ΔN}}_{R_2}^S+\▿{\mathrm{\ΔOrb}}_R^S-\▿{\mathrm{\ΔIon}}_{R_2}^S+\▿{\mathrm{\ΔTrop}}_R^S)---\left(2\right)$

wherein, K₂Representing a real number, LMD₂A wavelength representing the phase of the BDS carrier of the B2 frequency;a B2 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;ambiguity representing the B2 frequency carrier phase of the reference station R receiving the BDS satellite S;representing the B2 frequency carrier phase double-difference ionospheric delay error residual;

the B3 frequency double difference carrier phase observation equation multiplied by a real number is as follows:

$K_3\·{\mathrm{LMD}}_3\·\▿{\mathrm{\Δ\Φ}}_{R_3}^S=K_3\·(\▿{\mathrm{\Δ\ρ}}_R^S-{\mathrm{LMD}}_3\·\▿{\mathrm{\ΔN}}_{R_3}^S+\▿{\mathrm{\ΔOrb}}_R^S-\▿{\mathrm{\ΔIon}}_{R_3}^S+\▿{\mathrm{\ΔTrop}}_R^S)---\left(3\right)$

wherein, K₃Representing a real number, LMD₃A wavelength representing the phase of the BDS carrier of the B3 frequency;a B3 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;ambiguity representing the B3 frequency carrier phase of the reference station R receiving the BDS satellite S;representing a double difference in phase of the B3 frequency carrierAn off-layer delay error residual;

adding and integrating the double-difference carrier phase observation equations of the three frequencies to obtain the following formula:

wherein,

$l_{123}=(K_1+K_2+K_3)\·(\▿{\mathrm{\Δ\ρ}}_R^S+\▿{\mathrm{\ΔOrb}}_R^S+\▿{\mathrm{\ΔTrop}}_R^S),$

$d_{123}=K_1\·\▿{\mathrm{\ΔIon}}_{R_1}^S+K_2\·\▿{\mathrm{\ΔIon}}_{R_2}^S+K_3\·\▿{\mathrm{\ΔIon}}_{R_3}^S.$

3. the method for determining the triple-frequency carrier-phase integer ambiguity of the BDS reference station as claimed in claim 1, wherein the integer linear relationship among the triple-frequency carrier-phase integer ambiguities of B1, B2 and B3 is constructed in the step 3-1 as follows:

3-1-1, substituting the double-difference ionospheric delay error residual errors into a double-difference carrier phase observation equation of three frequencies after addition and arrangement according to the relation among double-difference ionospheric delay error residual errors borne by the double-difference carrier phase observation values B1, B2 and B3;

the relation among double-difference ionospheric delay error residuals borne by the B1, B2 and B3 double-difference carrier phase observed values is as follows:

$\▿{\mathrm{\ΔIon}}_{R_2}^S=\frac{f_1^2}{f_2^2}\·\▿{\mathrm{\ΔIon}}_{R_1}^S---\left(5\right)$

wherein,representing the B1 frequency carrier phase double-difference ionospheric delay error residual;representing the B2 frequency carrier phase double-difference ionospheric delay error residual; f. of₁B1 frequency, f, for BDS carrier phase₂B2 frequency, which is the BDS carrier phase;

$\▿{\mathrm{\ΔIon}}_{R_3}^S=\frac{f_1^2}{f_3^2}\·\▿{\mathrm{\ΔIon}}_{R_1}^S---\left(6\right)$

wherein,representing the B1 frequency carrier phase double-difference ionospheric delay error residual;representing the B3 frequency carrier phase double-difference ionospheric delay error residual; f. of₁B1 frequency, f, for BDS carrier phase₃B3 frequency, which is the BDS carrier phase;

the double-difference ionospheric delay error residual of the double-difference carrier-phase observation value of B1 is used for representing the double-difference ionospheric delay error residual of the double-difference carrier-phase observation value of B2 and B3, and the double-difference ionospheric delay error residual is substituted into a double-difference carrier-phase observation equation of three frequencies after addition arrangement, so that the following formula is obtained:

$d_{123}=K_1\·\▿{\mathrm{\ΔIon}}_{R_1}^S+K_2\·\frac{f_1^2}{f_2^2}\·\▿{\mathrm{\ΔIon}}_{R_1}^S+K_3\·\frac{f_1^2}{f_3^2}\·\▿{\mathrm{\ΔIon}}_{R_1}^S---\left(7\right)$

wherein, K₁、K₂、K₃Representing real number, and formula (7) is a double-difference ionospheric delay error residual in an integrated double-difference carrier phase observation equation of three frequencies after integration;

3-1-2, eliminating double-difference ionosphere delay error residual error, namely setting

3-1-3, arranging the double-difference carrier phase observation equation of the three frequencies after eliminating the double-difference ionosphere delay error residue, namely obtaining integer linear relations among the ambiguity of the B1, B2 and B3 three-frequency carrier phase whole-cycle;

the integer linear relation among B1, B2 and B3 three-frequency carrier phase integer ambiguity is as follows:

wherein,ambiguity representing the B1 frequency carrier phase of the reference station R receiving the BDS satellite S;ambiguity representing the B2 frequency carrier phase of the reference station R receiving the BDS satellite S;ambiguity representing the B3 frequency carrier phase of the reference station R receiving the BDS satellite S;c is the speed of light in vacuum;

a B1 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;a B2 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;a B3 frequency carrier phase observation indicating that the reference station R received the BDS satellite S; LMD₁A wavelength representing the phase of the BDS carrier of the B1 frequency; LMD₂A wavelength representing the phase of the BDS carrier of the B2 frequency;

representing the geometric range of the reference station R receiving the BDS satellite S;representing the double-differenced satellite orbit error residual,representing a double difference tropospheric delay error residual.

4. The method for determining the triple-frequency carrier-phase integer ambiguity of the BDS reference station as claimed in claim 1, wherein the integer linear relationship between the B1 and B2 double-frequency carrier-phase integer ambiguities is constructed in the step 3-2 as follows:

step 3-2-1, eliminating observed values and integer ambiguity of B3 frequency carrier phase, and settingK₃Is equal to 0, i.e

Wherein f is₁B1 frequency, f, for BDS carrier phase₂B2 frequency, which is the BDS carrier phase; f. of₃B3 frequency, which is the BDS carrier phase; k₁、K₂、K₃Represents a real number;

step 3-2-2, according to the set value in the step 3-2-1, arranging a double-difference carrier phase observation equation of three frequencies to obtain integer linear relations between double-frequency carrier phase integer ambiguities of B1 and B2;

the integer linear relation between B1 and B2 double-frequency carrier phase integer ambiguity is as follows:

${\mathrm{\ΔN}}_{R_2}^S=-\frac{K_1\·f_2}{K_2\·f_1}\·\▿{\mathrm{\ΔN}}_{R_1}^S-\frac{K_1\·f_2}{K_2\·f_1}\·\▿{\mathrm{\Δ\Φ}}_{R_1}^S-\▿{\mathrm{\Δ\Φ}}_{R_2}^S+\frac{(K_1+K_2)}{K_2\·{\mathrm{LMD}}_2}\·(\▿{\mathrm{\Δ\ρ}}_R^S+\▿{\mathrm{\ΔOrb}}_R^S+\▿{\mathrm{\ΔTrop}}_R^S)---\left(9\right)$

wherein,ambiguity representing the B1 frequency carrier phase of the reference station R receiving the BDS satellite S;ambiguity representing the B2 frequency carrier phase of the reference station R receiving the BDS satellite S;c is the speed of light in vacuum;a B1 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;a B2 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;representing the geometric range of the reference station R receiving the BDS satellite S;representing the double-differenced satellite orbit error residual,representing a double difference tropospheric delay error residual.

5. The method for determining the triple-frequency carrier-phase integer ambiguity of the BDS reference station as claimed in claim 1, wherein the integer linear relationship between the B1 and B3 double-frequency carrier-phase integer ambiguities is constructed in the steps 3-3 as follows:

step 3-3-1, eliminating observed values and integer ambiguity of B2 frequency carrier phase, and settingK₂Is equal to 0, i.e

Wherein f is₁B1 frequency, f, for BDS carrier phase₂B2 frequency, which is the BDS carrier phase; f. of₃B3 frequency, which is the BDS carrier phase; k₁、K₂、K₃Represents a real number;

3-3-2, arranging a double-difference carrier phase observation equation of three frequencies according to the set value in the step 3-3-1, and obtaining an integer linear relation between double-frequency carrier phase integer ambiguities of B1 and B3;

the integer linear relation between B1 and B3 double-frequency carrier phase integer ambiguity is as follows:

${\mathrm{\ΔN}}_{R_3}^S=-\frac{K_1\·f_3}{K_3\·f_1}\·\▿{\mathrm{\ΔN}}_{R_1}^S-\frac{K_1\·f_3}{K_3\·f_1}\·\▿{\mathrm{\Δ\Φ}}_{R_1}^S-\▿{\mathrm{\Δ\Φ}}_{R_3}^S+\frac{\left(K_1+K_3\right)}{K_3\·{\mathrm{LMD}}_3}\·\left(\▿{\mathrm{\Δ\ρ}}_R^S+\▿{\mathrm{\ΔTrop}}_R^S+\▿{\mathrm{\ΔOrb}}_R^S\right)---\left(10\right)$

wherein,ambiguity representing the B1 frequency carrier phase of the reference station R receiving the BDS satellite S;ambiguity representing the B3 frequency carrier phase of the reference station R receiving the BDS satellite S;c is the speed of light in vacuum;a B1 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;a B3 frequency carrier phase observation indicating that the reference station R received the BDS satellite S;presentation GinsengThe test station R receives the geometric distance of the BDS satellite S;representing the double-differenced satellite orbit error residual,representing a double difference tropospheric delay error residual.