CN110072187B - Method and device for distributing and receiving differential data - Google Patents
Method and device for distributing and receiving differential data Download PDFInfo
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- CN110072187B CN110072187B CN201910327912.2A CN201910327912A CN110072187B CN 110072187 B CN110072187 B CN 110072187B CN 201910327912 A CN201910327912 A CN 201910327912A CN 110072187 B CN110072187 B CN 110072187B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1851—Systems using a satellite or space-based relay
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/18523—Satellite systems for providing broadcast service to terrestrial stations, i.e. broadcast satellite service
- H04B7/18526—Arrangements for data linking, networking or transporting, or for controlling an end to end session
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1853—Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
- H04B7/18545—Arrangements for managing station mobility, i.e. for station registration or localisation
- H04B7/18547—Arrangements for managing station mobility, i.e. for station registration or localisation for geolocalisation of a station
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B7/00—Radio transmission systems, i.e. using radiation field
- H04B7/14—Relay systems
- H04B7/15—Active relay systems
- H04B7/185—Space-based or airborne stations; Stations for satellite systems
- H04B7/1853—Satellite systems for providing telephony service to a mobile station, i.e. mobile satellite service
- H04B7/18569—Arrangements for system physical machines management, i.e. for construction operations control, administration, maintenance
- H04B7/18573—Arrangements for system physical machines management, i.e. for construction operations control, administration, maintenance for operations control, administration or maintenance
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/02—Services making use of location information
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
- H04W4/06—Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W64/00—Locating users or terminals or network equipment for network management purposes, e.g. mobility management
Abstract
The invention discloses a method and a device for distributing and receiving differential data, wherein the distributing method comprises the following steps: acquiring differential data of a local reference station; receiving differential data sent by other nearby broadcast transmitting stations; and forming combined differential data by the differential data of the local reference station and the differential data sent by other nearby broadcast transmitting stations, sending the combined differential data out, so that a user terminal can receive the combined differential data sent by the broadcast transmitting stations and positioning by using the combined differential data. The receiving method comprises the following steps: receiving differential data, and acquiring geographical position information of a user according to the differential data; the differential data is distributed by the distribution method of the differential data. The distribution device is used for realizing the distribution method, and the receiving device is used for realizing the receiving method. The problems that the cost of erecting a special communication line is high and the working mode of point-to-point between a user and a base station is high in the prior art are solved.
Description
Technical Field
The invention relates to the technical field of the structure and networking of a continuous operation reference station network of a global navigation satellite system, in particular to a method and a device for distributing and receiving differential data.
Background
A Continuous Operation Reference Stations (CORS) of a Global Navigation Satellite System mainly comprises a plurality of GNSS (Global Navigation Satellite System) reference stations and a communication network. The reference station is a ground fixed station with known precise coordinates, and is used for observing navigation satellite signals in real time to obtain various kinds of observation data, and then transmitting the observation data to a data center or a user through a communication network.
The CORS can provide a variety of services including: a spatial positioning service, a spatial coordinate referencing service, a source data service, a time service, a satellite orbit service, etc. The spatial location service is one of the main service contents of the CORS. The CORS can meet wide application requirements with various positioning accuracies, and provides dynamic, continuous and high-accuracy spatial position service. A system providing such services is generally called a GNSS Ground-Based Augmentation system (GBAS), which is one result of applying differential positioning technology.
The differential positioning technology is to calculate the distance correction number from the reference station to the satellite by using the known precise coordinates of the reference station and send the correction number in real time. When observing satellite signals, the user reference station corrects the positioning result by using the received correction number so as to improve the positioning precision. The basic principle is that common errors related to distance or space exist in satellite signal observation values between different reference stations, and through difference processing, the common errors in different observation values are eliminated or reduced, so that a positioning result with higher precision is obtained.
However, the effectiveness of the differential positioning technique is based on the assumption that the error of the user terminal and the reference station is strongly correlated, i.e., the error has spatial correlation and becomes worse as the distance (baseline distance) between the user terminal and the reference station increases, and the residual error terms of satellite orbit bias, ionospheric and tropospheric delay all increase rapidly. This results in that at a longer baseline distance (for example, more than 50 km), the positioning result after the difference processing still contains a large observation error, and even the solution cannot be fixed, thereby reducing the positioning accuracy.
To overcome this problem, the simplest way is to increase the number of reference stations to reduce the baseline distance, but this will make the cost of CORS construction increase dramatically and undesirable. Therefore, multiple reference station differential positioning techniques have emerged. The difference correction information is calculated by utilizing a plurality of reference stations in a certain area, and an area type network error model is used for replacing a linear attenuation single-point error model, so that a more reliable, more uniform and more high-precision positioning effect is realized. The multi-reference station differential positioning technology can be further subdivided into technical systems such as Virtual Reference Stations (VRS), area correction numbers (FKP) and main and auxiliary stations (MAC) according to different operation modes.
In summary, to improve the positioning accuracy, a GNSS ground-based augmentation system with multi-reference station differential positioning service is proposed based on the CORS data, and the system configuration is generally shown in fig. 1.
The CORS data communication network of the existing scheme usually adopts special line connection such as optical fiber or microwave. However, since the site selection of the base station depends on the satellite observation condition, the geological condition and the net shape optimization principle, and population distribution is not referred to, the infrastructure of the environment where many reference stations are located is very lagged behind, and the cost for erecting a communication private line is extremely high. On the other hand, such dedicated line connections have poor anti-damage effects and slow recovery speed after damage when natural disasters such as typhoons and earthquakes occur, and at this time, high-precision positioning service is needed to play a role in disaster relief.
In addition, when the data center provides high-precision location service for users, based on the aforementioned multi-reference-station differential positioning technology, the users need to provide their own approximate location first, and then use technical methods such as Virtual Reference Station (VRS) to generate a set of differential data for the users individually. This point-to-point operation is very challenging for the multi-user service capability of the data center. Large-scale investment of computer infrastructure is needed, and a huge data center is built, so that the requirement of simultaneous online use of a large number of users can be met.
Disclosure of Invention
The invention mainly aims to provide a method and a device for distributing differential data, and aims to solve the problems that in the prior art, the cost for erecting a special communication line is high, and a point-to-point working mode is adopted between a user and a base station.
To achieve the above object, a method for distributing differential data includes the steps of:
acquiring differential data of a local reference station;
receiving differential data sent by other nearby broadcast transmitting stations;
and forming combined differential data by the differential data of the local reference station and the differential data sent by other nearby broadcast transmitting stations, sending the combined differential data out, so that a user terminal can receive the combined differential data sent by the broadcast transmitting stations and positioning by using the combined differential data.
Optionally, the differential data includes: observation data of a reference station or differential data of a virtual reference station, wherein the reference station and the virtual reference station are in one-to-one correspondence.
Optionally, before sending out the combined differential data, the method further includes:
and performing denoising processing on the difference data.
Optionally, before sending out the combined differential data, the method further includes:
judging whether a local reference station has a fault;
and when the local reference station is judged to have a fault, obtaining differential data of the virtual reference station according to the coordinates of the local reference station and differential data sent by other nearby broadcast transmitting stations, and replacing the differential data of the virtual reference station with the differential data of the local reference station to form combined differential data.
Optionally, the step of sending the combined differential data includes:
transmitting the differential data of the local reference station through a low-code-rate modulation channel;
and transmitting the received differential data transmitted by other nearby broadcast transmitting stations through a high-code-rate modulation channel.
In order to achieve the above object, the present invention further provides a method for receiving differential data, comprising the steps of:
receiving differential data, and acquiring geographical position information of a user according to the differential data; the differential data is distributed using the method of any of claims 1-4.
Optionally, the step of receiving the differential data by the user and acquiring the geographic location information of the user according to the differential data by the user includes:
the user terminal obtains double difference data according to the received difference data;
carrying out differential solution on the double-difference data to obtain a baseline vector coordinate;
and acquiring the geographical position information of the user terminal by using the baseline vector coordinates.
To achieve the above object, the present invention also provides a distribution apparatus of difference data, comprising:
a plurality of reference stations for acquiring the differential data;
the broadcast transmitting stations are used for acquiring differential data of a local reference station, receiving differential data sent by other nearby broadcast transmitting stations, forming combined differential data by the differential data of the local reference station and the differential data sent by other nearby broadcast transmitting stations, and sending the combined differential data out so that a user terminal can receive the combined differential data sent by the broadcast transmitting stations and position by using the combined differential data;
the reference station is set up corresponding to the broadcast transmitting station.
Optionally, the reference station is established in an area around the corresponding broadcast transmitting station, which meets the set conditions.
To achieve the above object, the present invention also provides a receiving apparatus of differential data, comprising:
the user terminal is used for receiving the differential data and acquiring the geographical position information of the user according to the differential data; the differential data is distributed by the distribution method of the differential data.
According to the technical scheme provided by the invention, differential data are broadcasted through a broadcasting station, so that the erection of a special line is saved, and a point-to-point working mode is solved by receiving data of a broadcasting transmitting station by a user; meanwhile, the construction quantity of the reference stations is reduced, and the erection cost is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
FIG. 1 is a schematic diagram of a GNSS ground-based augmentation system for a multi-reference-station differential positioning service;
fig. 2 is a schematic flow chart of a differential data distribution method according to the present invention;
FIG. 3 is a schematic diagram of a broadcast station and a corresponding reference station according to the present invention;
FIG. 4 is a diagram illustrating information transfer between broadcast stations according to the present invention;
FIG. 5 is a flow chart illustrating steps prior to sending out combined differential data in accordance with the present invention;
FIG. 6 is a schematic view of a specific process for tracking the displacement change of a corresponding reference station by using differential data of a virtual reference station according to the present invention;
fig. 7 is a schematic flow chart of a differential data receiving method according to the present invention;
fig. 8 is a schematic structural diagram of a differential data distribution apparatus according to the present invention;
fig. 9 is a schematic structural diagram of a broadcast transmitting station according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that all directional indicators (such as up, down, left, right, front, and back) in the embodiments of the present invention are only used to explain the relative position relationship between the components, the motion situation, and the like in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, the descriptions related to "first", "second", etc. in the present invention are only for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "connected," "secured," and the like are to be construed broadly, and for example, "secured" may be a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In addition, the technical solutions in the embodiments of the present invention may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination of technical solutions should not be considered to exist, and is not within the protection scope of the present invention.
As shown in fig. 2, the present invention provides a method for distributing differential data, comprising the steps of:
s1, acquiring differential data of the local reference station;
s2, receiving the differential data sent by other nearby broadcast transmitting stations;
and S3, forming combined differential data by the differential data of the local reference station and the differential data sent by other nearby broadcast transmitting stations, and sending the combined differential data out, so that the user terminal can receive the combined differential data sent by the broadcast transmitting stations and position by using the combined differential data.
The broadcast transmitting station is a broadcast signal transmitting tower constructed by the radio and television department, and the invention only utilizes the broadcast transmitting station to distribute signals without additionally increasing construction cost; meanwhile, differential data are broadcasted through a broadcasting station, and the erection of a special line is omitted; in addition, the reference station is correspondingly set with the broadcast transmitting station, and a corresponding local reference station is arranged near each broadcast transmitting station, so that the construction quantity of the reference stations is reduced, and the erection cost is reduced.
In one embodiment, the step of sending the combined differential data includes:
transmitting the differential data of the local reference station through a low-code-rate modulation channel;
and transmitting the received differential data transmitted by other nearby broadcast transmitting stations through a high-code-rate modulation channel.
Utilizing a low-code-rate modulation channel of digital broadcasting to broadcast differential data generated by a local reference station of a broadcast transmitting station; meanwhile, a digital broadcast receiver is arranged on a broadcast transmitting station, and receives differential data of local reference stations broadcast by other broadcast transmitting stations and broadcasts the differential data together through a high-bit-rate modulation channel of digital broadcast; the user terminal receives the signal of any broadcast transmitting station, namely the differential data of a plurality of reference stations can be received at the same time, and the data center can be cancelled by automatically realizing the multi-reference-station differential positioning technology at the terminal side.
In the specific implementation process, a local reference station is required to be erected firstly, the basic work of CORS construction is to erect a GNSS reference station, and the method is to locally erect one GNSS reference station at each broadcast transmitting station. The GNSS reference station is a ground fixing device and has accurate three-dimensional coordinates measured in advance. Through a multi-mode multi-frequency GNSS reference station, navigation satellites such as a Beidou satellite and a GPS are continuously observed, and after visible satellites are locked and tracked, corresponding GNSS observation data such as satellite ephemeris parameters, pseudo-ranges and carrier phase observation quantities are acquired. These real-time observation data are transmitted to the digital broadcast transmitter, modulated and then broadcast by the broadcast transmitting antenna, as shown in fig. 3.
The GNSS observation data comprise a plurality of system errors such as satellite/reference station clock error, satellite ephemeris error, troposphere delay, ionosphere delay and the like, most of the system errors are strongly related to the satellites and the reference stations, and most of the system errors can be eliminated or weakened through observation value difference.
The following is a description of the GNSS base observations observation equation;
in the formula:
the superscript s represents a satellite identifier, and the subscript A represents a reference station identifier;
the subscript i denotes the GNSS signal frequency number, λiRepresenting the wavelength of the corresponding frequency point;
δtAis the reference station clock error, δ tsIs the satellite clock error;
In addition to broadcasting the observation data of the local reference station, the digital broadcast receiver needs to acquire the observation data of the local reference station broadcasted by other broadcast transmitters, and then forward the observation data of the local reference station through the local digital broadcast transmitter, as shown in fig. 4.
The reference station differential data broadcast by the broadcast transmitting station can be divided into two types: the first type is local reference station (or virtual station) data; the second type is to forward the received data of local reference station (or virtual station) of peripheral broadcast transmitting station. The two types of data need to be processed differently when being broadcast. This is because the straight-line distance between any two adjacent broadcast transmitting stations is likely to be greater than the normal coverage distance of any one of the broadcast transmitting station signals. The method of the invention requires that the data of the local reference station broadcasted by the broadcast transmitting station can be transmitted to other surrounding broadcast transmitting stations through the broadcast signal, and the distributed CORS networking structure can be realized. And the second type of data belongs to forwarding and does not need to be transmitted back again.
Therefore, the broadcast signal carrying the first type of data requires a longer transmission distance, while the broadcast signal carrying the second type of data requires a larger transmission bandwidth (because it is data of a plurality of stations).
According to the shannon formula:
where C represents transmission bandwidth, B is signal bandwidth, S is signal power, and N is noise power. It should be noted that the signal bandwidth is not changeable depending on the communication standard definition and frequency plan, and the noise power is a true reflection of the signal receiving environment. The transmission of signals at a longer distance means that the received signal power is lower, and the transmission bandwidth needs to be reduced in order to ensure the normal transmission of the signals.
The method adopts a hierarchical modulation mode and adopts different signal modulation parameters for the first type of data and the second type of data. The first type of data uses modulation parameters with low code rate, and specifically can include modes such as lower FEC code rate, low-order constellation mapping, spread spectrum modulation and the like; the second type of data uses modulation parameters with high code rate to ensure sufficient data bandwidth. These modulation parameters are multiplexed with the first type of data, the second type of data, and other necessary information and are broadcast at the same time for use by the receiving user in demodulating.
For this purpose, the broadcast data multiplexing structure designed by the present invention is shown in table 1.
TABLE 1
In one embodiment, before sending out the combined differential data, the method further includes: and performing denoising processing on the difference data.
The data obtained through denoising processing is more accurate, and guarantee is provided for obtaining accurate positioning.
The differential data includes: observation data of a reference station or differential data of a virtual reference station, wherein the reference station and the virtual reference station are in one-to-one correspondence.
The displacement condition inevitably takes place for the reference station because of receiving the influence of reasons such as earthquake, reservoir area water pressure, plate motion at long-term operation in-process, if the displacement deformation has taken place for the reference station at the during operation, then the deformation deviation of reference station can be sneaked into in the observed data and form noise influence, if do not add processing then can lead to the user to solve the result distortion. Therefore, the difference data of the virtual station is added in the operation process, and the adverse effect caused by the problem can be effectively avoided.
In one embodiment, as shown in fig. 5, before the sending out the combined differential data, the method further includes:
judging whether a local reference station has a fault;
and when the local reference station is judged to have a fault, obtaining differential data of the virtual reference station according to the coordinates of the local reference station and differential data sent by other nearby broadcast transmitting stations, and replacing the differential data of the virtual reference station with the differential data of the local reference station to form combined differential data.
By utilizing the virtual reference station and through differential settlement, the displacement change condition of the reference station can be effectively tracked, the accuracy in the differential data transmission process is ensured, and correct data are provided for accurate positioning.
The construction process of the virtual reference station is as follows:
1. based on the coordinates of the local reference station, the observation data of the peripheral reference stations are used for calculating the observation data of a virtual reference station, and if the local reference station cannot be used due to reasons such as power failure, data interruption, equipment failure and the like, the virtual reference station data is directly used for replacing the local reference station data to be broadcast;
2. under the condition that the local reference station normally works, the calculated virtual reference station data is used for carrying out differential calculation on the local reference station to obtain an accurate positioning result, so that the long-term displacement change of the local reference station is tracked, and the accurate coordinate of the local reference station is continuously corrected;
3. and repeating the steps, recording the coordinate change condition of each reference station, detecting whether the relative motion trend exists between the reference stations, and improving the stability and reliability of the whole CORS system.
The virtual reference station is a reference station which does not exist physically, and a virtual observation value needs to be constructed based on a spatial correlation error model on the basis of observation data of other reference stations. Firstly, assuming that a pseudo-range observation value and a carrier phase observation value of a virtual reference station both exist, an inter-station single-difference observation equation of the virtual reference station and other existing reference stations for a common-view satellite S is as follows:
the virtual reference station observations are:
because the virtual reference station does not really exist, in the actual construction process, the clock error, the whole-cycle ambiguity, the multipath effect and the observation noise of the reference station are considered to be consistent with those of the existing reference station, and the satellite ephemeris error is ignored, so that the virtual reference station observation value calculation model is as follows:
by using the calculated virtual reference station data and performing differential calculation on the real-time observation data of the local reference station, an accurate real-time positioning result can be obtained for correcting the accurate coordinate of the reference station. At this time, the virtual reference station is considered as a reference station (coordinates are known), and the local reference station is considered as a rover (coordinates are not known to be solved).
The differential solution uses carrier phase observation data obtained by synchronously observing reference stations at two ends of a base line, establishes an error equation through differential processing, and then performs solution by using the least square principle to finally obtain a base line three-dimensional coordinate vector. In the process, the influence of errors at two ends of the base line has certain correlation, such as satellite clock error, orbit error, ionospheric delay, atmospheric delay and the like, and the errors can be greatly weakened through differential processing to obtain a high-precision relative position.
The difference processing is to calculate the difference between the observed values, and can calculate the difference between different reference stations and different satellites, and can calculate the difference between different epochsAnd (5) solving the difference. The reference station at both ends of the baseline is marked as A1And A2And is marked as S for the satellitejAnd SkAt epoch t1And t2And synchronous observation is carried out in time, 8 independent carrier phase observed values can be obtained and are respectively marked as:
the combinations of differences are of three types: single difference, double difference, triple difference.
(1) Single difference. The calculation of a difference between different reference stations is the most common form of single difference, and in addition, a difference between satellites and epochs can be calculated, and an observed value equation after the difference is as follows:
where f denotes the GNSS signal frequency, λ denotes the corresponding wavelength,
indicating the distance, deltat, of the reference station to the satelliteAA reference station clock difference is indicated and,
indicating the ionospheric delay error of the reference station,
representing the tropospheric delay error of the reference station.
From the above formula, it can be seen that the first difference is obtained between the reference stations, which can effectively weaken errors such as orbit error, ionosphere delay, troposphere delay, etc., if the two reference stations are close to each other, the correlation of the space correlation errors is strong, and the errors can be obviously inhibited through the single difference, so as to improve the positioning accuracy.
(2) Double difference. The continuous difference based on the single difference is called double difference, and the common form is to continuously obtain a single difference between satellites, and the observation equation is as follows:
it can be seen that the effect of the reference station clock difference is effectively eliminated by the double difference.
(3) And (4) three differences. Double differences can continue to be differenced, called triple differences. The commonly used form of the triple difference is to find the triple difference among the reference station, the satellite and the epoch in turn, and the observation equation is as follows:
the triple difference further eliminates the influence of integer ambiguity parameters on the basis of double differences, but because multiple differences can reduce the number of observation equations and can also have adverse effect on the solution, a double difference model is generally adopted.
In order to complete the baseline difference solution, the difference observation equation needs to be linearized, and taking the double differences as an example, the observation equation model is linearized to form an equation set with the following form:
in the formula (I), the compound is shown in the specification,
representing the directional cosine, k1-kn is the satellite marker,
and (4) carrying out vector solution on the equation system according to a least square criterion for the baseline vector coordinate. Because the reference station coordinates are known quantities, error quantities such as ionospheric delay, tropospheric delay, reference station clock error and the like can be considered to be eliminated through differential processing, and the unknowns needing to be solved by the equation set are only the three-dimensional coordinates of the rover station and the integer ambiguity.
In one embodiment, after the step of replacing the differential data of the virtual reference station with the differential data of the local reference station to form combined differential data, the method further comprises:
and tracking the displacement change of the corresponding reference station by using the differential data of the virtual reference station.
And tracking the displacement change of the corresponding reference station through the differential data of the virtual reference station to obtain the accurate displacement of the reference station, and eliminating the adverse effect caused by the displacement change of the reference station.
The specific calculation process of the influence value of the displacement of the reference station on the calculation result is as follows:
the coordinate of the reference station deviates, and the influence on the calculation result has great correlation with the length of the base line. Calculating the maximum effect of the reference coordinate deviation on the baseline solution can be represented by:
δS＝0.6×10-4×D×δB
wherein D represents a base length, δBIndicating the deviation of the reference coordinate, deltaSThe impact value is represented. According to the formula, the influence of the coordinate error of the reference station on the baseline solution under the worst condition can be calculated. Assuming a baseline distance of 30 kilometers, the effect of the reference coordinate deviation on the solution results may introduce a 1.8 times error.
The reference station utilizes the difference used in the process of tracking the displacement change by the virtual reference station as the carrier phase double-difference. As shown in fig. 6, the process of tracking the displacement change of the corresponding reference station by using the differential data of the virtual reference station includes:
s31, the digital broadcast receiver acquires the differential data of the peripheral reference station;
s32, removing the virtual reference station data;
s33, calculating virtual station observation data based on the local reference station coordinates;
s34, judging whether the local reference station has a fault;
s35, if the fault occurs, broadcasting the data of the virtual reference station;
s36, if there is no fault, broadcasting the data of the local reference station;
s37, performing positioning calculation on the local reference station by using the virtual station data;
s38, counting the positioning result for a long time, and comparing the positioning result with the known coordinates of the reference station;
s39, judging whether the coordinate error exceeds a threshold value;
s310, if the value exceeds the threshold value, updating the known coordinate of the local reference station, and setting the updated known coordinate as the known accurate coordinate value of the local reference station;
and S311, analyzing the relative movement displacement of the reference station according to the coordinate change condition.
By utilizing the virtual reference station, the reference station can effectively track the displacement change condition of the reference station through differential settlement, and can effectively prevent the occurrence of adverse effects such as positioning result distortion and the like caused by displacement change of the reference station through long-term data tracking.
As shown in fig. 7, the present invention further provides a method for receiving differential data, including the steps of:
receiving differential data, and acquiring geographical position information of a user according to the differential data; the differential data is distributed by the distribution method of the differential data.
The user receives the data of the broadcast transmitting station, and the technical problems of large multi-user service capability challenge, large investment scale of computer infrastructure, huge construction of a data center and the like of the data center caused by a point-to-point working mode are solved.
In one embodiment, the step of receiving the differential data by the user and acquiring the geographical location information of the user according to the differential data includes:
the user terminal obtains double difference data according to the received difference data;
carrying out differential solution on the double-difference data to obtain a baseline vector coordinate;
and acquiring the geographical position information of the user terminal by using the baseline vector coordinates.
According to the difference of the difference correction target quantity, the position difference, the pseudo-range difference and the carrier phase difference can be divided. The calculation complexity and the precision of the calculation result are gradually improved, the carrier phase difference implementation method is very complicated, but the positioning precision is highest and can reach centimeter level. In order to meet the coordinate correction requirement of the reference station, the invention adopts a carrier phase difference method.
As shown in fig. 8, the present invention also provides a distribution apparatus of difference data, comprising:
a plurality of reference stations for acquiring the differential data;
the broadcast transmitting stations are used for acquiring differential data of a local reference station, receiving differential data sent by other nearby broadcast transmitting stations, forming combined differential data by the differential data of the local reference station and the differential data sent by other nearby broadcast transmitting stations, and sending the combined differential data out so that a user terminal can receive the combined differential data sent by the broadcast transmitting stations and position by using the combined differential data;
the reference station is set up corresponding to the broadcast transmitting station.
Differential data are broadcasted by a broadcasting station, so that the erection of a special line is saved, and a point-to-point working mode is realized by receiving data of a broadcasting transmitting station by a user; meanwhile, the construction quantity of the reference stations is reduced, and the erection cost is reduced.
In one embodiment, the reference station is established in an area around the corresponding broadcast transmitting station, which meets the set conditions. The setting conditions shown are: the distance between the reference station and the broadcast antenna of the broadcast transmitting station is more than or equal to 100 meters and less than or equal to 5 kilometers.
The reference station is set around the broadcast transmitting station, and only one reference station needs to be set, so that differential data sharing can be realized through signal propagation between the broadcast transmitting stations, thereby forming a GORS networking structure and greatly reducing the erection cost.
The present invention also provides a receiving apparatus of differential data, comprising:
the user terminal is used for receiving the differential data and acquiring the geographical position information of the user according to the differential data; the differential data is distributed by the distribution method of the differential data.
The user terminal receives the differential data sent by the broadcast transmitting station and carries out differential settlement so as to correct the positioning result of the user terminal, thereby improving the positioning precision.
The user terminal is a terminal device with a positioning function, such as a mobile phone, a computer, an iPad, a telephone watch, a navigation device and the like.
As shown in fig. 9, the broadcast transmitting station includes:
a virtual station data calculation and selection module 101, configured to calculate and select differential data of a virtual station; the virtual station data calculation and selection module connects local reference station 201, digital receiver 1202, digital receiver 2203 through to digital receiver n 204.
A low-bit-rate modulation module 102, configured to perform low-bit-rate modulation on virtual station data received by a broadcast transmitting station;
a high-bit-rate modulation module 103, configured to perform high-bit-rate modulation on observation data received by the broadcast transmitting station and sent by a plurality of other digital broadcast receivers;
and a multiplexing module 104, configured to transmit the data modulated by the high-rate modulation module and the low-rate modulation module to a digital broadcast transmitter 105, where the digital broadcast transmitter is responsible for transmitting the data.
The technical scheme of the invention is that a GNSS reference station is erected near each existing broadcast transmitting station; utilizing a low-code-rate modulation channel of digital broadcasting to broadcast differential data generated by a local reference station of a broadcast transmitting station; meanwhile, a digital broadcast receiver is arranged on a broadcast transmitting station, and receives differential data of local reference stations broadcast by other broadcast transmitting stations and broadcasts the differential data together through a high-bit-rate modulation channel of digital broadcast; the user terminal receives the signal of any broadcast transmitting station, namely the differential data of a plurality of reference stations can be received at the same time, and the data center can be cancelled by automatically realizing the multi-reference-station differential positioning technology at the terminal side; because the system is a broadcast receiving system, the system can theoretically support the simultaneous use of an unlimited number of user terminals; the existing broadcast transmitting station has strong survivability and high recovery speed, and obviously improves the reliability of CORS.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (9)
1. A method of distributing differential data, comprising the steps of:
acquiring differential data of a local reference station;
receiving differential data sent by other nearby broadcast transmitting stations;
forming combined differential data by the differential data of the local reference station and the differential data sent by other nearby broadcast transmitting stations, sending the combined differential data out so that a user terminal can receive the combined differential data sent by the broadcast transmitting stations and positioning by using the combined differential data;
wherein the step of sending out the combined differential data comprises:
transmitting the differential data of the local reference station through a low-code-rate modulation channel;
and transmitting the received differential data transmitted by other nearby broadcast transmitting stations through a high-code-rate modulation channel.
2. The method according to claim 1, wherein the differential data includes: observation data of a reference station or differential data of a virtual reference station, wherein the reference station and the virtual reference station are in one-to-one correspondence.
3. The method for distributing differential data according to claim 1, wherein before sending out the combined differential data, the method further comprises:
and performing denoising processing on the difference data.
4. The method for distributing differential data according to claim 1, wherein before sending out the combined differential data, the method further comprises:
judging whether a local reference station has a fault;
and when the local reference station is judged to have a fault, obtaining differential data of the virtual reference station according to the coordinates of the local reference station and differential data sent by other nearby broadcast transmitting stations, and replacing the differential data of the virtual reference station with the differential data of the local reference station to form combined differential data.
5. A method of receiving differential data, comprising the steps of:
receiving differential data, and acquiring geographical position information of a user according to the differential data; the differential data is distributed using the method of any of claims 1-4.
6. The method for receiving differential data according to claim 5, wherein the step of receiving differential data and obtaining the geographical location information of the user according to the differential data comprises the steps of:
the user terminal obtains double difference data according to the received difference data;
carrying out differential solution on the double-difference data to obtain a baseline vector coordinate;
and acquiring the geographical position information of the user terminal by using the baseline vector coordinates.
7. An apparatus for distributing differential data, comprising:
a plurality of reference stations for acquiring the differential data;
the broadcast transmitting stations are used for acquiring differential data of a local reference station, receiving differential data sent by other nearby broadcast transmitting stations, forming combined differential data by the differential data of the local reference station and the differential data sent by other nearby broadcast transmitting stations, and sending the combined differential data out so that a user terminal can receive the combined differential data sent by the broadcast transmitting stations and position by using the combined differential data;
the reference station is correspondingly set up with the broadcast transmitting station;
wherein the broadcast transmitting station includes:
the low code rate modulation module is used for carrying out low code rate modulation on the virtual station data received by the broadcast transmitting station;
the high-code-rate modulation module is used for carrying out high-code-rate modulation on observation data which are received by the broadcast transmitting station and sent by a plurality of other digital broadcast receivers;
and the multiplexing module is used for transmitting the data modulated by the high-code-rate modulation module and the low-code-rate modulation module to a digital broadcast transmitter, and the digital broadcast transmitter is responsible for transmitting the data.
8. The apparatus according to claim 7, wherein the reference station is established in an area around the corresponding broadcast transmitting station, which area meets a predetermined condition.
9. An apparatus for receiving differential data, comprising:
the user terminal is used for receiving the differential data and acquiring the geographical position information of the user according to the differential data; the differential data is distributed using the method of any of claims 1-4.
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| CN201910327912.2A CN110072187B (en) | 2019-04-19 | 2019-04-19 | Method and device for distributing and receiving differential data |
| PCT/CN2019/088372 WO2020211162A1 (en) | 2019-04-19 | 2019-05-24 | Distributing and receiving methods and apparatuses for differential data |
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| CN112929833B (en) * | 2019-12-06 | 2022-05-06 | 中移(上海)信息通信科技有限公司 | Data distribution system and method |
| CN111290005B (en) * | 2020-03-04 | 2021-03-05 | 高维时空(北京)网络有限公司 | Differential positioning method and device for carrier phase, electronic equipment and storage medium |
| CN111308503A (en) * | 2020-03-05 | 2020-06-19 | 上海华测导航技术股份有限公司 | Method and device for converting space domain differential information into observation domain differential information |
| PL3904911T3 (en) * | 2020-03-05 | 2024-02-19 | Shanghai Huace Navigation Technology Ltd. | Method and device for converting state space representation into observation space representation |
| CN111447550B (en) * | 2020-03-24 | 2021-09-28 | 广东星舆科技有限公司 | Method and device for monitoring differential quality and computer medium |
| JP7369737B2 (en) | 2021-05-28 | 2023-10-26 | Ａｌｅｓ株式会社 | Positioning system, server, reference station, information distribution method, program, positioning target device and mobile object |
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