JP7183485B2 - Positioning Augmentation Signal Distribution Device and Positioning Augmentation Signal Distribution Method - Google Patents

Description

The technology according to the present disclosure relates to a positioning augmentation signal distribution device.

A technique is known in which a ground station terminal corrects a positioning error of a GNSS (Global Navigation Satellite System) using positioning augmentation information. For example, in Japan, the Quasi-Zenith Satellite System (QZSS), nicknamed "MICHIBIKI", has been commercialized, providing a centimeter-level positioning augmentation service (hereinafter referred to as "CLAS"). there is

To achieve centimeter-level accuracy, CLAS uses information from "electronic reference points," continuous GNSS stations located at 1,300 locations nationwide. This electronic control point is managed by the Geospatial Information Authority of Japan and has a GNSS receiver that receives radio waves from GNSS satellites. Information on the radio waves received by the GNSS CORSs is collected by the control station as observation data of the GNSS CORSs. A positioning augmentation signal distribution device in the control station generates a positioning augmentation signal from the collected observation data of the electronic reference points, and distributes it using the L6 signal of the quasi-zenith satellite system. The ground is divided into a plurality of areas, and a virtual grid is set in which grid points are arranged at regular intervals.

Positioning errors in GNSS are caused by various factors, including the delay of positioning signals in the ionosphere. If the propagation of the positioning signal is delayed in the ionosphere, an error in measuring the pseudorange from the GNSS satellite to the ground station terminal occurs, degrading the positioning accuracy. The positioning augmentation information includes a correction value for the delay of the positioning signal in the ionosphere. This correction value is hereinafter referred to as an ionospheric correction value. The ionospheric correction value is calculated for each grid point using the results of pseudorange measurements obtained from a plurality of electronic reference points.

Said positioning augmentation signal contains corresponding ionospheric corrections for each of the grid points. However, since CLAS uses the L6 signal of the quasi-zenith satellite system, it is subject to a transmission capacity limitation of about 2 kbps (bits per second). This means that the information amount of the positioning augmentation information needs to be suppressed (for example, compressed) to a certain amount in order to distribute the positioning augmentation signal all over the service target range.

For example, Patent Literature 1 discloses a technique for suppressing the information amount of positioning augmentation information to a certain amount and distributing it to ground station terminals. There are two methods in the disclosed technology, one is to widen the grid spacing within the range of the service target, and the other is to approximate the ionospheric correction value with a function and distribute only the coefficients of the approximate function. The method.

WO2016/088654

However, if there is a local ionospheric disturbance or the like, the accuracy of the correction information for that area deteriorates. In order to improve it, it is desirable to use observation values of more GEONET stations in the relevant area and to make the ionospheric correction value spatially finer only in the relevant area. However, with CLAS, the amount of information cannot be easily increased due to the above-mentioned transmission capacity limitation.

An object of the disclosed technology is to solve the above problems, and to provide a positioning augmentation signal distribution device that prevents deterioration of correction information accuracy in areas with localized ionospheric disturbances without increasing the overall amount of information. With the goal.

A positioning augmentation signal distribution device according to the technology disclosed herein is a positioning augmentation signal distribution device that distributes a positioning augmentation signal that reinforces a satellite positioning service using observation data from a plurality of electronic control points. is provided with an input interface, a processing circuit, and an output interface, the input interface outputs the number of electronic reference points used for each input area to the processing circuit, and the processing circuit outputs for each area , selecting the input number of electronic reference points to be used, and repetitively moving the spatially dense portion of the selected electronic reference points so as to be spatially sparse within the area is replaced with an electronic reference point that has not been selected.

Since the positioning augmentation signal distribution device according to the technique of the present disclosure has the above configuration, it is possible to prevent deterioration of the accuracy of correction information in an area with local ionospheric disturbance without increasing the overall amount of information.

1 is a diagram showing an overview of a positioning system according to Embodiment 1; FIG. 1 is a block diagram showing a configuration of a positioning augmentation signal distribution device according to Embodiment 1; FIG. It is a figure which shows the grid for every area set on the ground. FIG. 3 is a functional block diagram showing functions of a correction value distribution device of CLAS; 4 is a flow chart showing a processing flow of the positioning augmentation signal distribution device according to Embodiment 1; 6A is a block diagram showing a hardware configuration that implements the functions of the positioning augmentation signal distribution apparatus according to Embodiment 1. FIG. 6B is a block diagram showing a hardware configuration for executing software that implements the functions of the augmented positioning signal distribution apparatus according to Embodiment 1. FIG. FIG. 4 is a diagram showing an example of arrangement of electronic reference points in a certain area; FIG. 3 is a diagram showing electronic reference points selected within an area according to a conventional method; FIG. 4 is a diagram showing electronic reference points selected within an area by the technique according to the first embodiment; FIG. 9 is a functional block diagram showing functions of a positioning augmentation signal distribution device according to Embodiment 2;

Embodiment 1.
FIG. 1 is a diagram showing an outline of a positioning system according to Embodiment 1, and shows CLAS using a quasi-zenith satellite 1. FIG. The positioning system shown in FIG. 1 includes, for example, a quasi-zenith satellite 1, a GNSS satellite 2, a ground station terminal 3, a main control station 4, an electronic reference point 5, and an uplink station 6.

The quasi-zenith satellite 1 is the first satellite that transmits positioning augmentation information a to the ground station terminal 3 . The positioning augmentation information a is information used for correcting the positioning information b, and includes correction values for various errors. For example, the correction values included in the positioning augmentation information a include the correction value of the propagation delay of the positioning information in the ionosphere, the correction value of the propagation delay of the positioning information in the troposphere, and the error (integrity information) of these correction values.

A GNSS satellite 2 is a second satellite that transmits positioning information b to a ground station terminal 3 . For example, the GNSS satellites 2 are GPS (Global Positioning Systems) satellites. The positioning information b is information used for positioning the ground station terminal 3 .

The ground station terminal 3 is a terminal that performs positioning using the positioning information b. Further, the ground station terminal 3 performs positioning by correcting the positioning information b using the positioning augmentation information a. The quasi-zenith satellite 1 transmits positioning supplementary information c to the ground station terminal 3 in addition to the positioning supplementary information a. The complementary positioning information c is information that complements the positioning using the positioning information b by the ground station terminal 3 .

The main control station 4 includes the positioning augmentation signal distribution device according to the first embodiment. The positioning augmentation signal distribution device generates positioning augmentation information a. The positioning augmentation information a generated by the positioning augmentation signal distribution device of the main control station 4 is output to the uplink station 6 . The uplink station 6 transmits positioning augmentation information a to the quasi-zenith satellite 1 . The quasi-zenith satellite 1 distributes the positioning augmentation information a received from the main control station 4 via the uplink station 6 to the ground station terminal 3 as an L6 signal.

The electronic reference points 5 are arranged at a plurality of locations on the ground, receive positioning information b (GNSS signals) from the GNSS satellites 2, and combine the known position information of the electronic reference points 5 with the received positioning information b. is used to estimate the amount of error contained in the positioning information b, and correction information for correcting the estimated amount of error is transmitted to the main control station 4 . For example, in Japan, the electronic reference points 5 are arranged at about 1300 locations at intervals of about 20 km.

In CLAS, a virtual grid is set at regular intervals on the ground. The grid points are virtual electronic reference points arranged at regular intervals, and a correction value for the transmission delay of the positioning information b in the ionosphere is calculated for each grid point. This correction value is hereinafter referred to as an ionospheric correction value. For example, in Japan, grid points are set at approximately 350 locations at intervals of approximately 60 km. The quasi-zenith satellite 1 delivers positioning augmentation information a including ionospheric correction values every 30 seconds.

The ionospheric correction value is the delay amount of the positioning information in the distance from the GNSS satellite 2 to each grid point, which occurred in the ionosphere. The ground station terminal 3 measures the pseudorange between the GNSS satellite and the ground station terminal 3 using the positioning information b, and calculates the measured pseudorange using the ionospheric correction value included in the positioning augmentation information a. By correcting, a highly accurate pseudorange can be obtained.

By calculating the ionospheric correction value for each grid point, that is, by discretely allocating the ionospheric correction value to each grid point, the positioning augmentation information a including the ionospheric correction value can be discretely obtained from continuous information in the entire space. Compressed into information. The transmission capacity of the positioning augmentation information a including the ionospheric correction value is defined to be approximately 2 kbps.

As described above, the ionospheric correction value is calculated for each grid point. The positioning information b can be accurately corrected by using the positioning augmentation information a including the ionospheric correction values corresponding to the calculated grid points. That is, the narrower the grid interval is, the more the ground station terminal 3 can receive the ionospheric correction value corresponding to the grid point set closer, so the positioning accuracy is improved.

However, the transmission capacity of the positioning augmentation information a is limited (about 2 kbps), and the grid interval cannot be narrowed. On the other hand, in order to reduce the amount of information to be transmitted in the positioning augmentation information a, when the grid interval is expanded from the initial 60 km interval to an integer multiple of the interval (for example, 120 km interval), the positioning Accuracy degrades from the centimeter class to the digitimeter class. In addition, by transmitting only the coefficient when the ionospheric correction value is approximated by a function, the amount of information to be transmitted is reduced by including it in the positioning augmentation information a. to degrade to the order of digitimeters.

In addition, since the ionospheric disturbance produces an uneven ionosphere, the delay of the positioning information b in the ionosphere strongly affected by the ionospheric disturbance is different from the delay of the positioning information b in the ionosphere weakly affected by the ionospheric disturbance. Become. This delay difference greatly degrades the accuracy of the ionospheric correction value, which is the pseudorange correction value.

Therefore, in the positioning system according to Embodiment 1, the positioning augmentation signal distribution device transmits the positioning augmentation information a from the quasi-zenith satellite 1 based on the statistical information of the index value of the degree of ionospheric disturbance occurrence for each area. The spacing between points is preset. As a result, the grid interval is set according to the degree of influence of the ionospheric disturbance in the past, so that the ground station terminal 3 can maintain the positioning accuracy even if the ionospheric disturbance occurs. Furthermore, the grid interval is not fixed to a predetermined value (for example, 60 km), and the grid interval can be widened in areas where the degree of influence of ionospheric disturbance is low, so that the information amount of the positioning augmentation information a can be reduced. is possible.

FIG. 2 is a block diagram showing the configuration of the positioning augmentation signal distribution device according to Embodiment 1, which is provided in the main control station 4 shown in FIG. The positioning augmentation signal distribution device shown in FIG. to generate positioning augmentation information a corresponding to each of the plurality of grid points.

The database 40 is a database that stores index values of the degree of occurrence of ionospheric disturbances for each area. For example, past history data of ionospheric correction values corresponding to each grid point for each area is stored. Note that the ionospheric correction value is monitored for each area for a long period of time and stored in the database 40 until the degree of occurrence of ionospheric disturbance for each area becomes identifiable.

Areas strongly affected by ionospheric disturbances have large spatial variations in the ionospheric correction values for each grid point, while areas less affected by ionospheric disturbances have spatial variations in ionospheric correction values for each grid point. is small. That is, the ionospheric correction value can be an index value of the degree of occurrence of ionospheric disturbance.

Note that the database 40 may be provided in a device provided separately from the positioning augmentation signal distribution device according to the first embodiment. In this case, the positioning reinforcement signal distribution device according to Embodiment 1 is connected to the above device wirelessly or by wire, and reads data stored in the database 40 . Thus, the positioning augmentation signal distribution apparatus according to Embodiment 1 does not have to include the database 40 .

The grid setting unit 41 is a setting unit that sets intervals between grid points for transmitting the positioning augmentation information a from the quasi-zenith satellite 1 based on the statistical information of the index value of the degree of ionospheric disturbance occurrence for each area. For example, the grid setting unit 41 sets the grid point interval for transmitting the positioning augmentation information a based on the statistical information of the past history data of the ionospheric correction value for each area read from the database 40 .

FIG. 3 is a diagram showing grids for each area set on the ground. For example, Japan is divided into areas (1) to (12), and a grid is set for each area. The interval between grid points is statically set by the grid setting unit 41 . “Static” means that grid point intervals are set in advance based on the statistical information of the index value of the degree of ionospheric disturbance occurrence for each area.

The grid setting unit 41 sets grid intervals so that the total number of grid points corresponding to each piece of positioning augmentation information a distributed from the quasi-zenith satellite 1 is equal to or less than a specified value. The specified value is the total number of grid points that satisfy the transmission capacity limit of the positioning augmentation information a. The prescribed value is, for example, a value of about 250.

The calculation unit 42 calculates positioning correction information corresponding to grid points at intervals set by the grid setting unit 41 based on observation data observed by each of the plurality of electronic reference points 5 . The calculator 42 in Embodiment 1 calculates an ionospheric correction value, which is positioning correction information. The transmission unit 43 performs processing for transmitting the positioning augmentation information a including the ionospheric correction value calculated by the calculation unit 42 to the quasi-zenith satellite 1 . For example, the transmitter 43 transmits the positioning augmentation information a to the quasi-zenith satellite 1 via the uplink station 6 . The quasi-zenith satellite 1 distributes the positioning augmentation information a received from the main control station 4 to the ground station terminal 3 .

FIG. 4 is a functional block diagram showing functions of the CLAS correction value distribution device. FIG. 4A is a functional block diagram showing the functions of the correction value distribution device when electronic reference points to be used are determined in advance for each area. FIG. 4B is a functional block diagram showing functions of a CLAS correction value delivery device that dynamically selects electronic reference points. In this method of dynamically selecting GNSS CORSs, a table of GNSS GNSS CORSs with different densities is prepared in advance for each area. By switching the table for each area, the reference point density can be switched.

The relationship between the number of grids and the number of electronic reference points to be used is considered as follows. Even if the grid point intervals are determined for each area based on the statistical information of the index value of the degree of occurrence of ionospheric disturbances, if the number of electronic control points used for calculating the positioning augmentation information a is insufficient, each grid point The information obtained about is not meaningful. Conversely, it is conceivable that the number of GNSS CORSs used should be increased regardless of the number of grids. is disappearing. Considering the time consumed for calculation and calculation efficiency, it is desirable to change the number of electronic control points to be used according to the number of grids.

If the number of available electronic reference points is abundant and there are many options, the electronic reference points can be selected in a substantially grid pattern. Observation data of GNSS CORSs can be used directly without gridding.

The method for selecting the electronic reference point to be used is considered as follows. If the electronic reference points used in the area are spatially uneven, the positioning accuracy is degraded in the uneven areas. This is because the correction accuracy deteriorates when the point where the positioning is actually performed is far from the point where the correction information is generated. Therefore, in order to obtain a uniform correction effect, it is desirable that the particles are distributed as evenly as possible.

When selecting the GNSS CORSs to be used, the following points should also be noted. The ground station terminal 3 performs positioning using the positioning information b, and it is desired that the positioning point of the ground station terminal 3 is always surrounded by any of the selected electronic control points. In other words, it is desirable to select the electronic reference points along the coast to some extent as the electronic reference points to be used. This is because in CLAS, when performing positioning, correction information for four points around the positioning point of the ground station terminal 3 is interpolated to generate a correction value at the positioning point. Therefore, it is desirable to be surrounded by four points. If it is not surrounded by 4 points, it will be extrapolated. Since extrapolation has lower accuracy than interpolation, positioning accuracy also deteriorates. Although positioning points have been described, the same can be said for grid points.

The technology according to the first embodiment divides the ground into a plurality of areas and defines them. Here, the significance of defining the area is considered as follows. In the disclosed technique, since the number of grids for each area is determined according to the statistical degree of occurrence of ionospheric disturbances on the ground, the boundary of the area can be defined according to the spatial distribution shape of the degree of occurrence. can be considered. By doing so, compatibility with this technology, which changes the number of grids for each area, is improved. However, the area definition method is not limited to this. Areas may be defined according to the customarily often used "eight regional divisions" of Hokkaido, Tohoku, Kanto, Chubu, Kinki, Chugoku, Shikoku, and Kyushu-Okinawa. In addition, since the GNSS positioning information service is used for navigation of moving bodies such as vehicles, it may follow the area used in the navigation industry. FIG. 3 is an example showing how boundaries define areas on the ground. Also, FIG. 7 shows the electronic reference points in the area when the Tohoku region is used as the area unit.

In the technology according to Embodiment 1, the positioning augmentation signal distribution device spatially distributes the reference point number list for each area shown in FIGS. 4A and 4B in accordance with the number of electronic reference points used. Select automatically so as not to cause uneven density. A description of its operation follows.

FIG. 5 shows a processing flow of the augmented positioning signal distribution device according to the first embodiment. The operations described below are performed for all defined areas. For the sake of simplicity, it is assumed that the areas are numbered and work is carried out in order from the first area. Suppose the first area uses M electronic reference points. The number M of electronic reference points to be used in the first area is input via an input interface, which will be described later. First, the calculation unit 42 of the positioning augmentation signal distribution device, which will be described later, randomly selects M electronic reference points from the N electronic reference points arranged in the first area (ST1), and creates a candidate list. create.

The calculation unit 42 of the positioning augmentation signal distribution device calculates the distance to the closest electronic reference point for each of the M electronic reference points (ST2). This distance information is referred to herein as the "closest point distance". The calculation unit 42 of the positioning augmentation signal distribution device identifies the set of electronic reference points with the shortest distance to the closest point, and eliminates one of the identified sets of electronic reference points from the list of candidates ( ST3). At this point, the number of electronic reference points on the candidate list is M-1. A short closest point distance means that the distance between the electronic reference points is short, and that the points are spatially dense.

The calculation unit 42 of the positioning augmentation signal distribution device calculates the following for all NM electronic reference points that have not been selected from the first area. The calculation unit 42 adds one of the NM electronic reference points that have not been selected to the candidate list (ST4), and calculates the nearest point for each of the M electronic reference points in the updated candidate list. Calculate the distance (ST5) and record the minimum value (ST6). That is, the calculator 42 calculates the distance information and records the shortest value. The calculation unit 42 performs this process for all NM electronic reference points (ST7, ST4-ST6). As a result, the electronic control point with the maximum minimum value of the closest point distance is added as a new point (ST8). Selecting the electronic reference point that maximizes the minimum value of the nearest point distance means selecting the electronic reference point so as to be spatially coarse.

The calculation unit 42 of the positioning reinforcement signal distribution device performs the above selection flow until convergence (ST9, ST2-ST8). Here, convergence may be, for example, a state in which the electronic reference points are not interchanged. Alternatively, the minimum value of the closest point distance may be larger than a predetermined value. This is the convergence condition. After completing the correction of the candidate list for the first area, the second area, the third area, and so on are performed in order. Since the technique of the present disclosure designates the electronic reference points to be used for each area, it is possible to prevent the total number of electronic reference points from exceeding the above-described transmission capacity limit. Also, the electronic reference points can be selected so that there is no spatial bias in density within the area.

The problem to be addressed by the technology disclosed herein can be represented by the following formula. Let x _i (i=1, . . . , M) be the coordinates of each electronic reference point. Then, the closest point distance d _i,min calculated for each electronic reference point can be expressed by Equation 1 below. Also, the minimum value of the closest point distance can be expressed by Equation 2 below. Also, the problem of finding M electronic control points that maximize the minimum value of the closest point distance can be expressed by Equation 3.

The technology disclosed herein indicates that the calculation unit 42 of the positioning augmentation signal distribution device performs iterative calculations to substantially solve the so-called max min min problem shown in Equations 1 to 3 above.

A hardware configuration that implements the functions of the positioning augmentation signal distribution apparatus according to Embodiment 1 will be described below. The functions of the grid setting unit 41, the calculation unit 42, and the transmission unit 43 in the positioning augmentation signal distribution device according to Embodiment 1 are realized by a processing circuit. That is, the positioning augmentation signal distribution apparatus according to Embodiment 1 includes the functions of the positioning augmentation signal shown in FIG. 4 and a processing circuit for executing the processing shown in FIG. The processing circuit may be dedicated hardware, or may be a CPU (Central Processing Unit) that executes a program stored in memory.

6A is a block diagram showing a hardware configuration that implements the functions of the positioning augmentation signal distribution apparatus according to Embodiment 1. FIG. 6B is a block diagram showing a hardware configuration for executing software that implements the functions of the augmented positioning signal distribution apparatus according to Embodiment 1. FIG. 6A and 6B, the input interface 100 outputs the number of electronic reference points to be used for each input area to the processing circuit. The processing circuit 102 selects the input number of electronic reference points to be used for each area, and iteratively selects the spatially dense portion of the selected electronic reference points. Replace the non-selected electronic reference points in the area so as to be coarser. In addition, the input interface 100 is an interface that relays information that the grid setting unit 41 inputs from the database 40 and relays information that the calculation unit 42 inputs from the electronic reference point 5 . The output interface 101 is an interface that relays information output from the transmission unit 43 to the uplink station 6 .

If the processing circuit is the dedicated hardware shown in FIG. 6A, the processing circuit 102 may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA. (Field-Programmable Gate Array), or a combination thereof. Note that the functions of the grid setting unit 41, the calculation unit 42, and the transmission unit 43 may be realized by separate processing circuits. Also, these functions may be collectively realized by one processing circuit.

When the processing circuit is the processor 103 shown in FIG. 6B, the functions of the grid setting unit 41, the calculation unit 42, and the transmission unit 43 are realized by software, firmware, or a combination of software and firmware. Software or firmware is written as a program and stored in memory 104 . The processor 103 implements the functions of the grid setting unit 41 , the calculation unit 42 and the transmission unit 43 by reading and executing programs stored in the memory 104 . That is, the positioning augmentation signal distribution apparatus according to Embodiment 1 stores a program that, when executed by processor 103, results in the functions of the positioning augmentation signal shown in FIG. 4 and the processing shown in FIG. A memory 104 is provided for These programs cause the computer to execute the procedures or methods of the grid setting unit 41 , the calculation unit 42 and the transmission unit 43 . The memory 104 may be a computer-readable storage medium storing a program for causing the computer to function as the grid setting unit 41 , the calculation unit 42 and the transmission unit 43 .

The memory 104 includes, for example, non-volatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically-EPROM), Magnetic discs, flexible discs, optical discs, compact discs, mini discs, DVDs, and the like are applicable.

The functions of the grid setting unit 41, the calculation unit 42, and the transmission unit 43 may be partly realized by dedicated hardware and partly by software or firmware.
For example, the function of the transmission unit 43 is realized by a processing circuit as dedicated hardware, and the processor 103 reads out and executes programs stored in the memory 104 for the grid setting unit 41 and the calculation unit 42. can implement the function. As such, the processing circuitry may implement each of the above functions through hardware, software, firmware, or a combination thereof.

FIG. 7 shows the arrangement of all 134 electronic reference points arranged in the Tohoku area as an example of electronic reference points arranged in areas.

FIG. 8 shows the result of randomly selecting electronic reference points by designating the number of use as 24 among the 134 electronic reference points in FIG. FIG. 9 is a diagram showing the arrangement of 24 electronic reference points in the candidate list obtained by the technique according to the first embodiment. FIG. 9 shows that the arrangement of the GNSS CORSs selected by the disclosed technology has no spatial imbalance, and that the GNSS CORSs along the coast are uniformly selected.

As described above, the positioning augmentation signal distribution apparatus according to Embodiment 1 can specify the number of electronic reference points to be used for each area, automatically eliminates spatial unevenness in areas, and The number of GNSS CORSs used can be selected so that GNSS CORSs along the coast are uniformly selected. As a result, the technology disclosed herein can provide a positioning augmentation signal distribution device that prevents deterioration of correction information accuracy in areas where there is local ionospheric disturbance without increasing the overall amount of information.

Embodiment 2.
Embodiment 1 shows a case where the technology of the present disclosure is implemented by a processing circuit. Embodiment 2 shows a case of realizing it as an apparatus. FIG. 10 is a functional block diagram showing functions of the augmented positioning signal distribution apparatus according to the second embodiment.

The positioning augmentation signal distribution device according to the second embodiment includes a selection unit that randomly selects M electronic reference points, a calculation unit that calculates the closest point distance of each point, and selects/deletes the point with the shortest point distance. a selection/addition unit that selects and adds one from unselected points; a recalculation unit that recalculates the nearest point distance of each point; a record that records the minimum value of the nearest point distance of each point a determination unit that determines whether or not processing has been completed for all unselected points; a selection unit that selects as a new point a point that takes the maximum value from among the minimum values of the nearest point distances of each point; A determination unit that determines whether the minimum point distance is longer than the previous time.

The operation of the positioning augmentation signal distribution apparatus according to Embodiment 2 will be described below. In addition, the part which overlaps with Embodiment 1 is abbreviate|omitted. For the sake of simplicity, it is assumed that the areas are numbered and work is carried out in order from the first area. Suppose the first area uses M electronic reference points.

A selection unit that randomly selects M electronic reference points randomly selects M electronic reference points from the corresponding area and creates a list of candidates.

A calculation unit that calculates the closest point distance of each point calculates the "closest point distance", which is the distance to the closest electronic reference point, for each of the M electronic reference points.

A selection/deletion unit that selects/deletes a point with the shortest distance to the nearest point identifies a set of electronic reference points with the shortest distance to the nearest point, and selects one electronic reference point from the set of identified electronic reference points. Exclude from the candidate list. At this point, the number of electronic reference points on the candidate list is M-1. A short closest point distance means that the distance between the electronic reference points is short, and that the points are spatially dense.

The recalculator, which recalculates the nearest point distance of each point, calculates the following for all NM electronic reference points that have not been selected from the first area. The recalculator adds 1 of the NM unselected electronic reference points to the candidate list, and calculates the nearest point distance for each of the M electronic reference points in the updated candidate list. do.

A recording unit for recording the minimum value of the nearest point distance of each point records the minimum value of the calculated nearest point distance.

The determination unit that determines whether or not processing has been completed for all unselected points includes the processing of the calculation unit that recalculates the nearest point distance of each point described above, and the record that records the minimum value of the nearest point distance of each point. It is determined whether the processing of part has been performed at all NM electronic reference points. The above processing is performed at all NM electronic reference points.

The selection unit, which selects the point having the maximum value among the minimum values of the closest point distances of each point as a new point, adds the electronic reference point having the maximum value as a new point to the list of candidates. Selecting the electronic reference point that maximizes the minimum value of the nearest point distance means selecting the electronic reference point so as to be spatially coarse.

The determination unit that determines whether the minimum value of the nearest point distance of each point is longer than the previous time determines whether the flow of selection has converged by making this determination. The above conditions are determined in advance as convergence conditions. The technology according to the present disclosure iteratively deletes and adds the electronic reference point from the electronic reference point candidates to be used for each area until the convergence condition is satisfied. After completing the correction of the candidate list for the first area, the second area, the third area, and so on are performed in order. Since the technique of the present disclosure designates the electronic reference points to be used for each area, it is possible to prevent the total number of electronic reference points from exceeding the above-described transmission capacity limit. Also, the electronic reference points can be selected so that there is no spatial bias in density within the area.

As described above, the positioning augmentation signal distribution apparatus according to Embodiment 2 can specify the number of electronic reference points to be used for each area, automatically eliminates the spatial unevenness of density in the area, and The number of GNSS CORSs used can be selected so that GNSS CORSs along the coast are uniformly selected. As a result, the technology disclosed herein can provide a positioning augmentation signal distribution device that prevents deterioration of correction information accuracy in areas where there is local ionospheric disturbance without increasing the overall amount of information.

1 quasi-zenith satellite, 2 GNSS satellite, 3 ground station terminal, 4 main control station, 5 electronic reference point, 6 uplink station, 40 database, 41 grid setting unit, 42 calculation unit, 43 transmission unit, 100 input interface, 101 output interface, 102 processing circuit, 103 processor, 104 memory.

Claims (4)

A positioning augmentation signal distribution device that distributes a positioning augmentation signal that augments a satellite positioning service using observation data from a plurality of electronic reference points,
A positioning augmentation signal distribution device includes an input interface, a processing circuit, and an output interface,
The input interface outputs the number of electronic reference points used for each input area to the processing circuit,
The processing circuit selects the input number of electronic reference points to be used for each area, and iteratively spatially selects the spatially dense portions of the selected electronic reference points. A positioning augmentation signal distribution device characterized by replacing unselected electronic reference points in an area so as to be coarse. A positioning augmentation signal distribution device that distributes a positioning augmentation signal that augments a satellite positioning service using observation data from a plurality of electronic reference points,
A positioning augmentation signal distribution device includes an input interface, a processing circuit, and an output interface,
The input interface outputs M, which is the number of electronic reference points used for each input area, to the processing circuit;
The processing circuit is
(a) randomly selecting M electronic reference points from the N electronic reference points arranged in the k-th area with k=1, 2, . . . and creating a candidate list ;
(b) for each of the M electronic reference points according to step (a) , calculating a nearest point distance, which is the distance to the closest electronic reference point;
(c) identifying a set of electronic reference points with the shortest distance among the closest point distances related to step (b) , and selecting one of the identified electronic reference point sets from the candidate list related to step (a); removing from
(d) adding one of the NM unselected electronic reference points from the k-th area to the candidate list according to step (c);
(e) calculating the nearest point distance, which is the distance to the nearest electronic reference point, for each of the M electronic reference points in the candidate list according to step (d);
(f) recording the shortest value of the distance according to step (e);
(g) performing steps (d) through (f) for all NM electronic reference points;
(h) adding the electronic reference point with the maximum value recorded in step (f) as a new point;
(i) performing steps (b) through (h) until a convergence condition is met;
run the
Positioning Augmentation Signal Distribution Device. A positioning augmentation signal distribution method for a positioning augmentation signal distribution device that distributes a positioning augmentation signal that augments a satellite positioning service using observation data from a plurality of electronic control points,
A positioning augmentation signal distribution device includes an input interface, a processing circuit, and an output interface,
The input interface outputs the number of electronic reference points used for each input area to the processing circuit,
The processing circuit selects the input number of electronic reference points to be used for each area, and iteratively spatially selects the spatially dense portions of the selected electronic reference points. A positioning augmentation signal distribution method characterized by replacing non-selected electronic reference points in an area so as to be coarse. A positioning augmentation signal distribution method for a positioning augmentation signal distribution device that distributes a positioning augmentation signal that augments a satellite positioning service using observation data from a plurality of electronic control points,
A positioning augmentation signal distribution device includes an input interface, a processing circuit, and an output interface,
The input interface outputs M, which is the number of electronic reference points used for each input area, to the processing circuit;
The processing circuit is
(a) randomly selecting M electronic reference points from the N electronic reference points arranged in the k-th area with k=1, 2, . . . and creating a candidate list;
(b) for each of the M electronic reference points according to step (a), calculating a nearest point distance, which is the distance to the closest electronic reference point;
(c) identifying a set of electronic reference points with the shortest distance among the closest point distances related to step (b), and selecting one of the identified electronic reference point sets from the candidate list related to step (a); removing from
(d) adding one of the NM unselected electronic reference points from the k-th area to the candidate list according to step (c);
(e) calculating the nearest point distance, which is the distance to the nearest electronic reference point, for each of the M electronic reference points in the candidate list according to step (d);
(f) recording the shortest value of the distance according to step (e);
(g) performing steps (d) through (f) for all NM electronic reference points;
(h) adding the electronic reference point with the maximum value recorded in step (f) as a new point;
(i) performing steps (b) through (h) until a convergence condition is met;
run the
A positioning augmentation signal delivery method.

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