1. A method for monitoring real-time correction service integrity of a wide area difference enhancement system is characterized by comprising the following steps:

step 1: the data processing server generates wide-area differential real-time correction service by using the received observation data from the ground observation station, and simultaneously constructs test statistic through a carrier phase residual error mathematical computation model;

step 2: according to the statistical distribution of the errors, the data processing server calculates the integrity threshold of the integrity system to obtain a check threshold;

and step 3: comparing the test statistic obtained in the step 1 with the test threshold obtained in the step 2, filtering the wide area correction service corresponding to the test statistic exceeding the threshold value, and generating an unavailable warning sign to remind a user receiver of stopping using the affected data, so as to realize the integrity monitoring before broadcasting of the real-time correction service;

and 4, step 4: sending the integrity monitoring result before broadcasting to a communication satellite by using a satellite communication link and broadcasting to a ground observation station;

and 5: the ground observation station circularly monitors the influence of the correction service of each satellite on the precision single-point positioning precision by using a precision single-point positioning observation model according to the observation information, the real-time correction service and the integrity monitoring result before broadcasting, and when the positioning result exceeding the limit is detected, the corresponding real-time correction service is identified as an abnormal state, the integrity monitoring information after broadcasting is generated, and the integrity monitoring result is sent to the data processing server;

step 6: and the data processing server counts the integrity monitoring results before and after broadcasting to generate integrity monitoring information, sends the integrity monitoring information to a communication satellite through a satellite communication link, and finally broadcasts the integrity monitoring information to the real-time users.

2. The method of claim 1, wherein the method comprises the steps of: step 1 the test statistic includes the orbit clock residual res_Orb+ClkTropospheric residual res_RegTropoIonospheric residual res_RegIonoAnd satisfies the following conditions:

wherein: phi_IFCombining phase observations for ionospheric-free layers, phi_GFFor the purposes of a geometrically independent phase observation,for the model-corrected satellite position, X_rIn order for the user to be at the receiver location,is the geometric distance from the satellite to the receiver, c is the speed of light, Δ t_rIn order for the receiver to be out of clock,for the model-corrected satellite clock error, T_estFor tropospheric delay estimates, T_modFor model-corrected tropospheric delay, I_modFor model-corrected ionospheric delay, n_IFInteger ambiguity, n, for ionospheric combinations_GFInteger ambiguity as a geometrically independent combination, b_r,GFFor the purpose of geometrically independent receiver offsets,the geometry-independent satellite bias after model correction.

3. The wide-area differential augmentation system real-time correction service integrity monitoring method as claimed in claim 1 or 2, wherein: step 2, according to the statistical distribution of the errors, the data processing server calculates the integrity threshold of the integrity system, and the obtained inspection threshold specifically comprises the following steps:

0.5m+T_dquality indicators for track and clock corrections; 0.5m + T_dA quality index for tropospheric correction; 1.0m + T_dQuality index for ionospheric corrections, wherein T_dCalculating according to the distribution characteristics and the confidence coefficient of the historical data;

probability of dangerous misleading information assigned by user given detection processSatisfies the following conditions:

where σ and b are by statistics res_Orb+Clk、res_RegTropoAnd res_RegIonoThe standard deviation and the mean value obtained by distribution fitting can obtain the corresponding detection threshold T_d。

4. The wide-area differential augmentation system real-time correction service integrity monitoring method as claimed in claim 1 or 2, wherein: the precise single-point positioning observation model in the step 5 specifically comprises the following steps:

P＝ρ+c(dt_r-dt^s)+I+T+d_orb+d_tid+d_rel+ε_P

in the formulaP respectively represents a carrier phase and a code measurement pseudo range observed value; ρ represents the geometric distance between the user and the satellite; c represents the speed of light in vacuum; dt_rRepresenting the receiver clock error; dt^sRepresenting the satellite clock error; i represents an ionospheric error; t represents tropospheric error; d_orbRepresenting an ephemeris error; d_tidIndicating a tidal error; d_relRepresenting relativistic effect errors; n represents the integer ambiguity; d_antRepresenting an antenna phase error; d_phwIndicating a phase winding error;representing a carrier phase observation; epsilon_pRepresenting code-measurement pseudorange observation noise.

Background

The precision and reliability of the positioning result of the satellite navigation system are the most important performance indexes in the field of navigation positioning research. The precise single-point positioning technology based on the wide-area difference real-time correction service becomes one of effective methods for marine navigation positioning of ships by the characteristics of single antenna, low cost and the like, and can provide a high-precision positioning result meeting the requirement of ship navigation. With the expansion of the application of the precise single-point positioning technology, in the application related to life safety, the reliability of the navigation positioning result gradually becomes a performance index which is the first guarantee. The method has important engineering significance for expanding the application of satellite navigation positioning in the fields of ocean exploration, development, search and rescue and the like, establishing a wide-area differential real-time correction service integrity monitoring system and ensuring high precision and reliability of user positioning results.

Although a plurality of research institutions and companies provide wide-area differential correction service at present, the broadcasted information does not contain integrity monitoring information, and the application of the service in the life safety related field is limited. The reliability of high precision positioning is affected by multiple types of integrity risk sources. In order to ensure the reliability of high-precision positioning, it is necessary to closely monitor various types of risk sources affecting high-precision positioning. How to generate the integrity information of the wide-area differential real-time correction service by using the integrity monitoring technology is a key point for truly realizing the integrity monitoring of the wide-area differential real-time correction service. In summary, to meet the requirements of high-reliability and high-precision navigation positioning performance, the wide-area differential real-time correction service must receive strict integrity check, and can warn the user in a few seconds through a certain way under the condition that an additional system is uncertain whether the additional system is safely available or not. Therefore, the wide-area differential real-time correction service integrity monitoring system is designed, and has great significance for rapidly broadcasting potential system faults to users.

Disclosure of Invention

In view of the foregoing prior art, the technical problem to be solved by the present invention is to provide a method for monitoring the integrity of service of a wide area differential enhancement system in real time correction, which provides fast and highly reliable integrity monitoring information.

In order to solve the technical problem, the method for monitoring the real-time correction service integrity of the wide area difference enhancement system comprises the following steps:

step 1: the data processing server generates wide-area differential real-time correction service by using the received observation data from the ground observation station, and simultaneously constructs test statistic through a carrier phase residual error mathematical computation model;

step 2: according to the statistical distribution of the errors, the data processing server calculates the integrity threshold of the integrity system to obtain a check threshold;

and step 3: comparing the test statistic obtained in the step 1 with the test threshold obtained in the step 2, filtering the wide area correction service corresponding to the test statistic exceeding the threshold value, and generating an unavailable warning sign to remind a user receiver of stopping using the affected data, so as to realize the integrity monitoring before broadcasting of the real-time correction service;

and 4, step 4: sending the integrity monitoring result before broadcasting to a communication satellite by using a satellite communication link and broadcasting to a ground observation station;

and 5: the ground observation station circularly monitors the influence of the correction service of each satellite on the precision single-point positioning precision by using a precision single-point positioning observation model according to the observation information, the real-time correction service and the integrity monitoring result before broadcasting, and when the positioning result exceeding the limit is detected, the corresponding real-time correction service is identified as an abnormal state, the integrity monitoring information after broadcasting is generated, and the integrity monitoring result is sent to the data processing server;

step 6: and the data processing server counts the integrity monitoring results before and after broadcasting to generate integrity monitoring information, sends the integrity monitoring information to a communication satellite through a satellite communication link, and finally broadcasts the integrity monitoring information to the real-time users.

The invention also includes:

1. the test statistics in step 1 include the track clock residual res_Orb+ClkTropospheric residual res_RegTropoIonospheric residual res_RegIonoAnd satisfies the following conditions:

wherein: phi_IFCombining phase observations for ionospheric-free layers, phi_GFFor the purposes of a geometrically independent phase observation,for the model-corrected satellite position, X_rIn order for the user to be at the receiver location,is the geometric distance from the satellite to the receiver, c is the speed of light, Δ t_rIn order for the receiver to be out of clock,for the model-corrected satellite clock error, T_estFor tropospheric delay estimates, T_modFor model-corrected tropospheric delay, I_modFor model-corrected ionospheric delay, n_IFInteger ambiguity, n, for ionospheric combinations_GFInteger ambiguity as a geometrically independent combination, b_r,GFFor the purpose of geometrically independent receiver offsets,the geometry-independent satellite bias after model correction.

2. In step 2, according to the statistical distribution of the errors, the data processing server calculates the integrity threshold of the integrity system, and the obtained inspection threshold specifically comprises:

0.5m+T_dquality indicators for track and clock corrections; 0.5m + T_dA quality index for tropospheric correction; 1.0m + T_dQuality index for ionospheric corrections, wherein T_dCalculating according to the distribution characteristics and the confidence coefficient of the historical data;

probability of dangerous misleading information assigned by user given detection processSatisfies the following conditions:

where σ and b are by statistics res_Orb+Clk、res_RegTropoAnd res_RegIonoThe standard deviation and the mean value obtained by distribution fitting can obtain the corresponding detection threshold T_d。

3. The precise single-point positioning observation model in the step 5 specifically comprises the following steps:

P＝ρ+c(dt_r-dt^s)+I+T+d_orb+d_tid+d_rel+ε_P

in the formulaP respectively represents a carrier phase and a code measurement pseudo range observed value; ρ represents the geometric distance between the user and the satellite; c represents the speed of light in vacuum; dt_rRepresenting the receiver clock error; dt^sRepresenting the satellite clock error; i represents an ionospheric error; t represents tropospheric error; d_orbRepresenting an ephemeris error; d_tidIndicating a tidal error; d_relRepresenting relativistic effect errors; n represents the integer ambiguity; d_antRepresenting an antenna phase error; d_phwIndicating a phase winding error;representing a carrier phase observation; epsilon_pRepresenting code-measurement pseudorange observation noise.

The invention has the beneficial effects that: the invention utilizes carrier phase observation of a plurality of ground observation stations to form test statistic for testing the precision of satellite real-time correction service, acquires a test threshold by combining statistical distribution characteristics of satellite end errors, and performs double tests on real-time correction service which is not broadcasted and real-time correction service which is broadcasted through comparison between the test statistic and the test threshold based on an integrity monitoring theory and a precise single-point positioning method, thereby generating high-reliable integrity monitoring information and timely broadcasting the information to a user end to assist the user to realize high-precision and high-reliability navigation positioning. The invention integrates the technologies of wide-area differential real-time correction service generation, satellite communication, computer big data processing and the like, and performs double inspection on the real-time correction service which is not broadcasted and the real-time correction service which is broadcasted based on a carrier phase residual error calculation model and a precise single-point positioning method, thereby generating high-reliable integrity monitoring information and timely broadcasting the integrity monitoring information to a user terminal, and fully ensuring the high precision and the high reliability of user navigation positioning in the fields related to life safety. According to the method, a carrier phase residual error calculation model and a precise single-point positioning method are fully utilized, a ground observation station is combined, double inspection is carried out on undelivered real-time correction service and broadcasted real-time correction service, comprehensive integrity monitoring information is generated, the integrity monitoring information is finally broadcasted to a user, and the user is assisted to realize high-precision and high-reliability navigation positioning. The system also provides strong signal tracking functions of multi-path inhibition and anti-interference enhancement by deploying the most advanced geodetic antenna and the receiver, and forms redundant network connection of monitoring stations to ensure the stability and reliability of monitoring results. The invention monitors the integrity before and after broadcasting and generates high-reliability integrity detection information based on the reception of the observation data of the ground observation station.

Drawings

Fig. 1 is a schematic diagram of an embodiment of a wide-area differential real-time correction service integrity monitoring system using the present invention.

Detailed Description

The invention is further described with reference to the drawings and the detailed description.

The invention comprises the following steps: step 1, a data processing server generates wide-area differential real-time correction service by using the received observation data from a ground observation station, and simultaneously constructs test statistic through a carrier phase residual error mathematical computation model. And 2, calculating the integrity threshold of the integrity system by the data processing server according to the statistical distribution of the errors to obtain a detection threshold. And 3, comparing the test statistic with a test threshold, filtering the wide area correction service corresponding to the threshold value, and generating a corresponding warning sign to remind a user receiver of stopping using the affected satellite, so that the integrity monitoring before broadcasting of the real-time correction service is realized. And 4, sending the integrity monitoring result before broadcasting to a communication satellite by using a satellite communication link and broadcasting the integrity monitoring result to the ground observation station. And 5, integrating the observation information, real-time correction service and the integrity monitoring result before broadcasting by the ground observation station, realizing the integrity monitoring after broadcasting by using a precision single-point positioning precision trend analysis method, and sending the integrity monitoring result to the data processing server. And 6, counting the integrity monitoring results before and after broadcasting by the data processing server to generate integrity monitoring information, transmitting the integrity monitoring information to a communication satellite through a satellite communication link, and finally broadcasting the integrity monitoring information to a real-time user. And (3) a test statistic calculation model selected for the integrity monitoring of the orbit clock, the troposphere and the ionosphere constructed in the step 1 is used for refining a test statistic calculation mode. The empirical test threshold and the quality index calculation mode thereof defined in the step 2 improve the accuracy of the test threshold calculation. And 5, monitoring the integrity after broadcasting by adopting a precision single-point positioning precision trend analysis method. And 3, step 6 and step 6 comprehensively utilize dual integrity monitoring before and after broadcasting to generate comprehensive integrity monitoring information in time, so that high precision and high reliability of a user positioning result are fully guaranteed.

With reference to fig. 1, the method specifically includes the following steps:

step 1, constructing test statistic of integrity monitoring before broadcasting

The different types of residual errors for monitoring the integrity of the observation data of the invention comprise the track clock residual error res_Orb+ClkTropospheric residual res_RegTropoIonospheric residual res_RegIonoThese residuals are used as test statistics for pre-broadcast integrity monitoring. They all haveThe corresponding mathematical calculation model is shown in formulas (1), (2) and (3):

wherein: phi_IFCombining phase observations for ionospheric-free layers, phi_GFFor the purposes of a geometrically independent phase observation,for the model-corrected satellite position, X_rIn order for the user to be at the receiver location,is the geometric distance from the satellite to the receiver, c is the speed of light, Δ t_rIn order for the receiver to be out of clock,for the model-corrected satellite clock error, T_estFor tropospheric delay estimates, T_modFor model-corrected tropospheric delay, I_modFor model-corrected ionospheric delay, n_IFInteger ambiguity, n, for ionospheric combinations_GFInteger ambiguity as a geometrically independent combination, b_r,GFFor the purpose of geometrically independent receiver offsets,the geometry-independent satellite bias after model correction.

a. Orbit clock residual res_Orb+ClkIs an ionosphere-free linear combination phi observed through the phase of the original carrier_IFGeometric distance, andsatellite clock error correctionIonosphere-free combined carrier phase ambiguity n_IFTroposphere zenith delay T_estThe sum of the differences therebetween. Receiver coordinate component X_rIt can be derived from the a priori coordinates or estimated as part of the ambiguity fixing. Since the resulting residual error still contains unknown inter-system receiver offsets associated with the navigation system, the res associated with the navigation system must finally be removed_Orb+ClkAverage value.

b. Tropospheric residual res_RegTropoIs only distinguished from the former by the tropospheric tilt delay T given by the tropospheric model in the real-time modified service data stream_modInstead of tropospheric day-wise estimated delays mapped to the line of sight. The tropospheric residuals used for integrity monitoring include the combined error of all geometric corrections, such as orbit, clock and tropospheric corrections.

c. Ionospheric residual res_RegIonoIs determined by the ionospheric tilt delay I given by the ionospheric model_modCorrecting in real time ionospheric satellite bias transmitted by service data streamingThe original carrier-phase observations are generated by a geometrically independent linear combination and ambiguity. Similar to the generation of the orbit clock residual, the receiver bias b_γ,GFIs removed by ionospheric residual mean.

Step 2, calculating the check threshold of integrity monitoring before broadcasting

Based on the statistical distribution characteristics of carrier phase residual errors, the following monitoring thresholds are defined for integrity monitoring before broadcasting:

0.5m+T_dquality indicators for track and clock corrections; 0.5m + T_dA quality index for tropospheric correction; 1.0m + T_dQuality indicators for ionospheric corrections. Wherein, T_dThe method can be obtained by calculation according to the distribution characteristics and the confidence coefficient of historical data.

For a given risk misleading information probability, the calculation of the check threshold is as shown in equation (4):

in the formula (I), the compound is shown in the specification,given the probability of dangerous misleading information assigned to the detection process for the user, σ and b are calculated by counting res_Orb+Clk、res_RegTropoAnd res_RegIonoThe standard deviation and the mean value obtained by distribution fitting can obtain the corresponding detection threshold T_d。

Step 3, integrity monitoring before broadcasting

And (3) comparing the test statistic obtained in the step (1) with the test threshold obtained in the step (2), filtering the real-time correction service corresponding to the test statistic exceeding the threshold value, and generating an unavailable warning sign for reminding a user to stop using the affected data so as to complete the integrity monitoring before broadcasting of the real-time correction service.

Step 4, broadcasting integrity monitoring information before broadcasting

And packaging the integrity monitoring result before broadcasting into a data stream according to a standard protocol, then sending the integrity monitoring result before broadcasting to a communication satellite by using a satellite communication link, and broadcasting to a ground observation station through the communication satellite.

Step 5, post-broadcast integrity monitoring

The ground observation station combines the observation information, the real-time correction service and the monitoring result before broadcasting, based on the precise single-point positioning technology, circularly monitors the influence of the correction service of each satellite on the precise single-point positioning precision, when the positioning result exceeding the limit is detected, marks the corresponding real-time correction service as an abnormal state, generates the integrity monitoring information after broadcasting, and finally sends the result to the data processing server to complete the integrity monitoring after broadcasting.

The precise single-point positioning observation model is shown in formulas (5) and (6):

P＝ρ+c(dt_r-dt^s)+I+T+d_orb+d_tid+d_rel+ε_P (6)

in the formulaP respectively represents a carrier phase and a code measurement pseudo range observed value; ρ represents the geometric distance between the user and the satellite; c represents the speed of light in vacuum; dt_rRepresenting the receiver clock error; dt^sRepresenting the satellite clock error; i represents an ionospheric error; t represents tropospheric error; d_orbRepresenting an ephemeris error; d_tidIndicating a tidal error; d_relRepresenting relativistic effect errors; n represents the integer ambiguity; d_antRepresenting an antenna phase error; d_phwIndicating a phase winding error;representing a carrier phase observation; epsilon_pRepresenting code-measurement pseudorange observation noise.

Step 6, generating integrity monitoring information and broadcasting the integrity monitoring information to the real-time users

The data processing server processes the integrity monitoring results before and after broadcasting to generate comprehensive integrity monitoring information, then sends the integrity monitoring results to a communication satellite through a satellite communication link, and finally broadcasts the integrity monitoring results to a real-time user.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.