JP2007170900A - Satellite-positioning system, terminal, ionosphere correction data receiving/processing method, and its program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance positioning accuracy in a short period by efficiently transmitting/receiving ionosphere correction data between a satellite and the ground, even without receiving all the ionosphere correction data, in satellite positioning. <P>SOLUTION: The satellite delivers ionosphere correction data on grid points, in the order of circled numbers (by interval of six) in Fig. 4(a) where the number of grid points related to the ionosphere correction data (hereinafter, to be referred to as correction data) is a hundred, for example. That is, delivery is performed in the order of (A, 1), (H, 1), (E, 2), (B, 3), (I, 3) ... (G, 9), (D, 10), (A, 1) ... . In contrast to this, a terminal performs interpolation on the correction data on grid points in not-yet-received portions, when fifteen grid points have been received from the first received correction data (or simultaneously with the reception of correction data in the vicinity of the position of the terminal 3) and performs correction calculation on positioning data, assuming that the correction data have been received in a pseudo-manner, on the grid points on the surface as a whole. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a satellite positioning system that transmits and receives ionospheric correction data for correcting positioning by a satellite.

On June 30, 2004, the Ministry of Internal Affairs and Communications received a report from the Information and Communication Council regarding “development of technical conditions related to the function of notifying the location information of callers in emergency calls from mobile phones”. As a target schedule, the mobile phone of the third generation mobile phone to be newly provided after April 2007, as a general rule, to support the location information notification function by GPS (Global Positioning Systems) positioning method, In April 2011, the goal is to reach a penetration rate of 90%.
On the other hand, in the field of space development, the Ministry of Education, Culture, Sports, Science and Technology, Ministry of Economy, Trade and Industry, and Ministry of Land, Infrastructure, Transport and Tourism are proceeding with the technological development of a quasi-zenith satellite system with a positioning function. want to be.
Under such circumstances, demand for positioning services is not only steadily increasing, but it is expected that the service market with added value, such as higher accuracy of positioning, will increase dramatically.

  In Japan, there are two services that transmit error correction data of DGPS (Differential GPS) as a broadcast. One is a service that superimposes error correction data on a medium beacon radio wave operated by the Japan Coast Guard and broadcasts it. The other is a service provided to users by placing DGPS error correction data on FM audio multiplex broadcasting. In any service, data is distributed in accordance with the standard of RTCM (Radio Technical Commission for Maritime Services), and the service for distributing ionospheric correction data as data corresponding to the latitude and longitude grid points is not provided.

For positioning correction using geostationary satellites, the Wide Area Augmentation System (WAAS) using the INMARSAT (International Marine Satellite telecommunication Organization) of the United States and the Multi-functional Transport Satellite (MTSAT) ) Using satellite augmentation system (MSAS, MTSAT Satellite-based Augmentation System). For ionosphere correction data (delay amount expressed as a vertical delay distance), grid points are set approximately every 5 degrees in latitude and longitude (which differs slightly depending on latitude), and information on available grid points ( Mask information) and a delay amount corresponding to each grid point. The receiver can perform highly accurate positioning when it has received all necessary data. If the latest data has not been transmitted or received, interpolation is performed using other received latest data. An example relating to grid points is described in Patent Document 1.
JP 2004-198291 A

  However, for ionospheric correction data, the entire surface of the earth is divided into eight regions, and within each region, data for each grid point is distributed in order from the corner of the area, so the area around where you are located. There is a problem that it is necessary to wait for a predetermined time before receiving data. In positioning correction using a mobile phone, correction is performed assuming an ionosphere model using eight parameters transmitted from a GPS satellite, but there is a problem that accuracy is not good.

  Therefore, in view of the above problems, the present invention efficiently transmits and receives ionosphere correction data between the satellite and the ground in satellite positioning, and can achieve positioning accuracy in a short time without receiving all ionosphere correction data. It is an object to provide means for improving.

  The present invention that solves the above-described problems includes a first satellite that transmits positioning information for performing positioning, a second satellite that transmits correction information for correcting positioning information, and positioning from the first satellite. A satellite positioning system including a terminal that receives information and correction information from a second satellite and performs positioning, wherein the correction information includes ionospheric correction data for correcting a delay of radio waves in the ionosphere. The second satellite covers the area to which correction information is to be transmitted, and transmits ionospheric correction data corresponding to the points specified by the latitude and longitude for each point spaced by a predetermined interval. The ionosphere correction data for each point transmitted from the second satellite is sequentially received, and when the number of received ionosphere correction data exceeds a predetermined value, the ionosphere correction data of the unreceived point is received. The main feature is to perform positioning by correcting the positioning information received from the first satellite based on the received ionospheric correction data and the interpolated ionospheric correction data based on interpolation using ionospheric correction data at other points. To do. The present invention includes other satellite positioning systems, terminals, ionospheric correction data reception processing methods, and programs thereof.

  According to the present invention, in satellite positioning, high-precision positioning is possible without receiving all necessary data, and the positioning time can be shortened. Further, it is possible to effectively utilize resources (line capacity) on the delivery side without impairing the function and performance of the terminal that receives data.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

≪Overview of GPS satellite and quasi-zenith satellite≫
As shown in FIG. 1, a satellite positioning system 1 using GPS satellites and quasi-zenith satellites provides positioning information when a terminal 3 as a positioning device performs positioning using a GPS satellite (first satellite) 2a. Or the correction information is acquired from the quasi-zenith satellite (second satellite) 2b to improve the positioning accuracy. Examples of the terminal 3 include portable terminals such as notebook personal computers, PDAs (Personal Digital Assistants) and mobile phones, and mobile objects such as in-vehicle audio devices and navigation systems. Note that the quasi-zenith satellite 2b may transmit only correction information.

  The GPS satellite 2a in the United States has a circular orbit with an orbital inclination angle of 55 degrees and an orbital period of about 12 hours (the orbital period is 1/2 synchronized with the rotation period of the earth). In places where the latitude is 55 degrees or less, the elevation angle is up to 90 degrees. However, since the orbital period is about 12 hours, the length of time at which the elevation angle looks high is shorter than that of the quasi-zenith satellite 2b (detailed later). In general, the GPS satellite 2a uses a satellite or a group of satellites whose orbit altitude is 19,000 to 25,000 km (so-called MEO orbit) and broadcasts a positioning signal to a moving body, and a geostationary orbit. It is a satellite or a group of satellites that broadcast positioning signals for mobile objects. The GPS satellite 2a includes, for example, GPS / NAVSTAR (Global Positioning System / Navigation Satellite Timing and Ranging), GLONASS (Global Navigation Satellite System), Galileo (European proposed global navigation system), and a transport multipurpose satellite. In the case of a satellite or a group of satellites that orbit the altitude of 19,000 to 25,000 km orbiting and broadcasting a positioning signal for a mobile object, the satellite elevation angle in Japan is 90 because the MEO orbit is used. Although it is widely distributed below 50 degrees, the length of time that appears at a high elevation angle is shorter than that of the quasi-zenith satellite. In the case of a satellite or a group of satellites that use geostationary orbits to broadcast positioning signals for moving bodies, the elevation angle from Japan varies depending on the location, but is about 50 degrees at maximum (in the case of Tokyo) and does not vary with time.

  On the other hand, the quasi-zenith satellite 2b is a satellite that has an orbital period of about 24 hours (or the orbital period is synchronized with the rotation period of the earth) and appears to be suspended for a long time at a high elevation when viewed from Japan. (Orbit satellites, including figure 8 orbit satellites) The quasi-zenith satellite 2b includes, for example, HEO (Highly Elliptic Orbit), and constellation with three satellites (so that these satellites can be seen simultaneously no matter where the observer is on the earth) In this case, it is assumed that the operating satellites are always visible at almost an elevation angle of 70 degrees or more when viewed from the main islands of Japan and Okinawa. Considering the edge of Japan (the northernmost edge, etc.), the minimum elevation angle of the operating satellite is about 65 degrees. Further, the quasi-zenith satellite 2b may be a so-called 8-shaped orbit satellite. In this case, when a constellation is constituted by three satellites, the operating satellite is always at an elevation angle of 60 degrees or more when viewed from the mainland Japan and Okinawa. A visible orbit is assumed. Similarly, when considering the edge of Japan (the northernmost edge, etc.), the minimum elevation angle of the operating satellite is about 50 degrees. As the types of positioning signals, two types of signals, the same as the GPS signal and the DGPS signal, are assumed.

  Therefore, the quasi-zenith satellite 2b is visible in the vicinity of the service area where, for example, three (or four) artificial satellites are replaced when the main island of Japan and Okinawa are service areas. It means an artificial satellite group having a time, preferably an elevation angle of 70 degrees or more, and at least an elevation angle of about 50 degrees or more (45 degrees or more). As for the movement of the artificial satellite group, the first artificial satellite is visible above the service area, and when the first artificial satellite moves away from the service area, the second artificial satellite is near the service area. It becomes visible in the sky, and when the second satellite moves away from the service area, the third satellite becomes visible in the sky near the service area, and the third satellite moves away from the service area. The first satellite is visible again in the sky near the service area. The same is true even if it is composed of four artificial satellites.

  The GPS satellite 2a outputs a GPS signal (positioning data) composed of pseudo-noise code, orbit information, time correction information, and other information (parameters of ionosphere model, satellite health information, orbit information of other satellites, etc.). When the terminal 3 receives three GPS signals, it can measure the latitude and longitude of the mobile object (for example, assuming that the altitude is zero meters above sea level) Is necessary). If four or more GPS signals are received, three-dimensional positioning with sea level added can be performed.

  The quasi-zenith satellite 2b uses ionospheric correction data (hereinafter referred to as the ionospheric correction data for improving the positioning accuracy by removing the positioning data similar to the GPS signal and the error generated when the radio wave superimposed with the GPS signal passes through the ionosphere. Broadcasts correction data). By transmitting positioning data using such a satellite wave, the number of satellites that output GPS signals that can be captured is increased to expand the location and time where positioning is possible, and by sending correction data, Compared with the case where correction data is transmitted using terrestrial waves such as FM broadcasting, the cover area can be widened. In addition, correction data is easily received even in places where radio waves are difficult to reach, such as in valleys of high-rise buildings.

  As described above, when the positioning data and the correction data are transmitted using the quasi-zenith satellite 2b, it is necessary to sequentially switch the quasi-zenith satellite 2b so that the elevation angle viewed from the terminal 3 is always a certain angle or more. For this reason, by performing handover between the quasi-zenith satellites 2b, the quasi-zenith satellite 2b is always visible at a high elevation angle from the same position.

  The correction data is calculated using the electronic reference station 7 shown in FIG. The electronic reference station 7 includes an antenna, a receiver, and a communication device, receives a GPS signal emitted from the GPS satellite 2a, calculates the distance between the GPS satellite 2a and the antenna, and obtains the position of the electronic reference station 7. . A large number of such electronic reference stations 7 are provided in the country, and the positioning results of each electronic reference station 7 are collected in the correction data calculation unit 8 through the communication line 7a. The correction data calculation unit 8 obtains correction data for the entire country of Japan by, for example, multiply averaging errors between the actual position of the electronic reference station 7 and the positioning result. The correction data calculated in this way is uplinked from the uplink facility 9 to the quasi-zenith satellite 2b in a format such as RTCM, and is multiplexed and broadcast to the terminal 3.

≪Terminal configuration and overview≫
FIG. 2 is a diagram illustrating a configuration of the terminal. The terminal 3 includes a communication unit 31, a processing unit 32, a storage unit 33, a display unit 34, and an operation unit 35. The communication unit 31 has a function of receiving positioning data and correction data from the satellite 2 (GPS satellite 2a, quasi-zenith satellite 2b), and includes an antenna and a receiver. For example, in the case where the terminal 3 is a mobile phone, a communication unit (not shown) having a communication function inherent to the mobile phone, which is different from the communication unit 31 for the positioning function, is further provided ( The same applies to other terminals and devices). The processing unit 32 accumulates the positioning data and correction data received by the communication unit 31 in the storage unit 33, processes the data, and stores the result in the storage unit 33. Further, the data stored in the storage unit 33 is displayed on the display unit 34 in accordance with an instruction from the operation unit 35. The processing unit 32 is realized by a CPU (Central Processing Unit) executing a program stored in the storage unit 33 and loaded into a predetermined memory. The storage unit 33 stores and reads data according to instructions from the processing unit 32. The storage unit 33 is realized by a nonvolatile storage device such as a flash memory or a hard disk device. The display unit 34 has a function of displaying data in accordance with an instruction from the processing unit 32, and is realized by, for example, a liquid crystal display. The operation unit 35 has a function of providing the user with operation of the terminal 3 and a function of transmitting an instruction content by the operation to the processing unit 32, and is realized by an operation button, a keyboard, a mouse, or the like.

<< Configuration of transmission data >>
FIG. 3 is a diagram showing a configuration of data transmitted by the quasi-zenith satellite. The quasi-zenith satellite 2b transmits positioning data and correction data (ionosphere correction data) as shown in FIG. Here, a pseudo noise code (not shown) is transmitted at a chip rate of 1.023 Mcps, for example, corresponding to each data. The positioning data is transmitted at a bit rate of 50 bps, for example. There are two types of positioning data: visible satellites and non-visible satellites, and the positioning data of visible satellites are transmitted in a shorter cycle than the positioning data of non-visible satellites. This is because the transmission of the positioning data of the visible satellite is prioritized over the positioning data of the non-visible satellite in performing highly accurate positioning. On the other hand, the correction data is transmitted every 60 seconds using, for example, a bandwidth of 250 bps to 1 kbps. The correction data is normally considered to be transmitted once in order from Hokkaido like the correction data X. However, in the embodiment of the present invention, for example, the correction data Y makes a round from Hokkaido to Okinawa Prefecture. The coarse data is transmitted periodically. In practice, correction data other than ionospheric correction (orbit correction, clock correction, etc.) is also transmitted, but it is not shown here.

≪How to send and receive correction data≫
The correction data (ionosphere correction data) is data specific to the ionosphere that corresponds to the grid points of latitude and longitude and has regional differences and temporal changes. The amount of satellite radio wave delay in the ionosphere is expressed as the vertical delay distance and vertical direction. This is expressed in terms of the delay time of the electron and the electron column density in the vertical direction of the ionosphere. After the correction data is transmitted from the quasi-zenith satellite 2b and received by the terminal 3, the terminal 3 corrects the distance between each satellite 2 and the terminal 3 measured from other received data (positioning data). Used to do. Here, since the correction data changes depending on the region and time, in order to improve the positioning accuracy, it is required to use the latest correction data of the grid point as close as possible to the position specified by the positioning data.

  When the quasi-zenith satellite 2b transmits correction data corresponding to the grid points of latitude and longitude, the quasi-zenith satellite 2b does not transmit in the order in which the grid points are located, but transmits the entire surface (area) to be transmitted (for example, the whole of Japan). In order to cover in a short time, correction data of discrete grid points with predetermined intervals are transmitted. As a result, the entire surface can be covered sparsely with the first round of correction data, and the entire surface can be covered with the first round of correction data after the start of reception, regardless of when the reception starts. it can.

  When receiving the correction data, the terminal 3 first starts reception at an arbitrary timing, and performs position correction when the correction data for the first round is received. At this time, since all the correction data corresponding to the grid point has not been received, the correction data at the grid point of the unreceived portion is interpolated based on the received correction data and included in the surface to be transmitted. Simulates correction data for all grid points. As a result, it is possible to perform highly accurate positioning as compared with the case where independent positioning without using correction data is performed. At this point, it may not be possible to achieve the high accuracy that is finally obtained because the correction data for all grid points is not complete. The correction data becomes highly accurate, thereby improving the positioning accuracy. Even during the correction data for the first round is being received, interpolation may be performed using the correction data already received at that time.

≪Correction data distribution example 1≫
FIG. 4 is a diagram illustrating the order of grid points on a surface to which correction data is to be transmitted. For example, as shown in FIG. 4A, when there are 100 grid points related to correction data, grid point correction data is distributed in the order of the numbers described in the circles (every six). And That is, (A, 1), (H, 1), (E, 2), (B, 3), (I, 3)... (G, 9), (D, 10), (A, 1 ), ... in this order. At this time, the terminal 3 can cover the entire surface sparsely when receiving the first 15 data, regardless of which grid point correction data is received.

  At the terminal 3, when 15 correction data are received from the first received correction data (or at the same time as receiving correction data near the position of the terminal 3), the correction data of the grid points in the unreceived portion are interpolated, and a pseudo surface is obtained. The correction calculation is started on the assumption that the correction data of the entire grid point has been received. Subsequently, when the correction data of the grid point of the unreceived portion is received, the correction data is updated and the interpolation of the correction data of the grid point of the unreceived portion is performed every time, thereby improving the accuracy of the correction data.

≪Correction data distribution example 2≫
As shown in FIG. 4B, for example, when there are 81 grid points on the surface to which correction data is to be transmitted, correction data is distributed in the order of the numbers described in the circles in the figure. It shall be. That is, (A, 1), (C, 1), (E, 1), (I, 1), (B, 2)... (F, 9), (H, 9), (A, 1 ), ... in this order. At this time, the terminal 3 can cover the entire surface sparsely when receiving the first 41 data, regardless of which grid point correction data is received.

  In terminal 3, when 41 correction data are received from the first received correction data (or at the same time as the reception of correction data near the position of terminal 3), the correction data of the grid points in the unreceived portion are interpolated, and a pseudo surface is obtained. The correction calculation is started on the assumption that the correction data of the entire grid point has been received. Subsequently, when the correction data of the grid point of the unreceived portion is received, the correction data is updated and the interpolation of the correction data of the grid point of the unreceived portion is performed every time, thereby improving the accuracy of the correction data.

≪Procedure for receiving correction data≫
FIG. 5 is a flowchart showing a procedure of correction data reception processing by the terminal. Here, the terminal 3 may start receiving correction data from the quasi-zenith satellite 2b at any timing.

  First, the terminal 3 receives and accumulates correction data transmitted from the quasi-zenith satellite 2b (step S501). Specifically, the communication unit 31 of the terminal 3 receives the correction data transmitted from the quasi-zenith satellite 2 b and outputs it to the processing unit 32. Then, the processing unit 32 inputs correction data from the communication unit 31 and stores the correction data in the storage unit 33. Next, the processing unit 32 checks whether or not the number of the latest correction data stored in the storage unit 33 is greater than or equal to a predetermined value (step S502). Here, the predetermined value is, for example, the minimum number of correction data, and the number can be designated on the transmission side (quasi-zenith satellite 2b or correction data calculation unit 8). This is because, when the order of grid points to which correction data is distributed and the arrangement of the grid points are changed, the minimum necessary number of correction data is not known on the receiving side (terminal 3), and the sending side does not know the correction data. It means that it is notified by adding to. In addition, it is good also as a check whether it is larger than a predetermined value whether the check is more than a predetermined value. If the number of the latest correction data is not equal to or greater than the predetermined value (No in step S502), the process returns to step S501 to receive and store the next correction data. Then, the reception and storage of the correction data is continued until the latest correction data is provided for the minimum necessary number.

  If the number of the latest correction data is equal to or greater than the predetermined value (Yes in step S502), that is, if the minimum necessary number of correction data is received and accumulated, the processing unit 32 of the terminal 3 It is checked whether or not the latest correction data of all grid points on the surface to be received has been received (step S503). If the latest correction data for all grid points has not been received (No in step S503), it means that there is a grid point for which correction data has not been received, and the correction data that has not been received has already been received, Interpolation is performed based on the latest correction data of other grid points accumulated in the storage unit 33, and the interpolation is stored in the storage unit 33 (step S504). As a method of interpolating unreceived correction data, for example, an average value of received correction data at three to four grid points around a grid point to be interpolated is used.

  If the latest correction data of all grid points has been received (Yes in step S503), no interpolation is necessary, so step S504 is skipped and the process proceeds to step S505. Subsequently, the processing unit 32 performs a correction calculation of the positioning data based on the correction data (step S505). According to this, ionospheric correction can be performed using correction data without waiting for completion of reception of all correction data, and the accuracy of satellite positioning can be improved. Note that before receiving the minimum necessary number of correction data, interpolation may be performed for correction data of grid points in the unreceived portion. For example, when correction data near the current position of the terminal 3 is received, correction data of other grid points in the vicinity may be interpolated.

  In addition, when the high accuracy of satellite positioning is required, it is necessary to increase the accuracy of the correction data. Therefore, when the correction calculation is continued (Yes in step S506), the terminal 3 returns to step S501, continues to receive correction data, accumulates correction data at each grid point (step S501), and Interpolation is performed on the correction data at the received grid point (step S504). In step S <b> 501, the correction data interpolated because it has not been received last time is updated with the newly received correction data, and stored in the storage unit 33. According to this, it is possible to realize satellite positioning with higher accuracy than the positioning result obtained by first receiving the minimum necessary number of correction data. Furthermore, the most accurate satellite positioning can be realized by finally receiving the latest correction data of all grid points.

  Note that it is conceivable that the determination as to whether or not to continue the correction calculation in step S506 is made based on conditions set in advance in the storage unit 33 of the terminal 3 by the user. For example, when the user wants to confirm his / her position only once, when the positioning error is within a predetermined value or when all necessary correction data has been received, the correction calculation is not continued (No in step S506). It is conceivable to end the correction data reception process. In addition, when it is desired to perform positioning continuously by applying to the navigation system, it is conceivable to set so that it is determined that the correction calculation is always continued (Yes in step S506).

  According to the above, first, among the grid points covering the surface to which correction data is to be transmitted, the correction data of all grid points are not received, but a predetermined number of grid points covering the area sparsely. Since the correction data is received and the positioning data is corrected using the correction data, the positioning accuracy can be improved in a short time. Next, by further receiving correction data and increasing the number of grid points that have received correction data, it is possible to reduce the number of unreceived grid points to which correction data should be interpolated, thus improving the accuracy of the correction data, The positioning accuracy can be improved step by step. Further, by receiving correction data and receiving correction data of all grid points, the accuracy of the correction data is most improved and the highest positioning accuracy can be realized.

  Such an effect is, for example, when the terminal 3 is mounted on a vehicle and it has become impossible to measure the position because it entered the tunnel, but it may be somewhat rough when leaving the tunnel. This is useful when you want to know the location of Then, as time elapses, the positioning accuracy increases step by step.

  Although the embodiment of the present invention has been described above, the program executed by the processing unit 32 of the terminal 3 shown in FIG. 1 is recorded on a computer-readable recording medium, and the program recorded on the recording medium is stored in the computer system. It is assumed that the terminal 3 according to the embodiment of the present invention is realized by being read and executed. The program may be provided to the computer system via a network such as the Internet. Further, a semiconductor chip in which a program is written may be provided.

<< Other embodiments >>
An example of the preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment, and can be appropriately changed without departing from the spirit of the present invention. For example, in the above-described embodiment, the terminal 3 is described so that the most accurate positioning is possible when the correction data is received at all grid points for the correction data transmission target surface. The correction data may be received again from the first round. According to this, since the delay amount of the ionosphere changes with the passage of time, it is possible to maintain highly accurate positioning by repeating interpolation and positioning while the terminal 3 continuously receives the latest correction data. it can.

It is a figure which shows the structure of the satellite positioning system which concerns on embodiment of this invention. It is a figure which shows the structure of the terminal which concerns on embodiment of this invention. It is a figure which shows the structure of the data which a quasi-zenith satellite transmits. It is a figure which shows the order of the grid point which concerns on the ionosphere correction data which a quasi-zenith satellite transmits, (a) shows the example which transmits the ionosphere correction data of a grid point every six, (b) shows every other The example which transmits the ionospheric correction data of a grid point is shown. It is a flowchart which shows the procedure of the ionosphere correction data reception process by a terminal.

Explanation of symbols

1 Satellite positioning system 2 Satellite 2a GPS satellite (first satellite)
2b Quasi-zenith satellite (second satellite)
3 Terminal 32 Processing unit 33 Storage unit

Claims (10)

A first satellite for transmitting positioning information for positioning;
A second satellite for transmitting correction information for correcting the positioning information;
A terminal that receives positioning information from the first satellite and correction information from the second satellite and performs positioning;
A satellite positioning system comprising:
The correction information is
Includes ionospheric correction data for correcting radio wave delay in the ionosphere,
The second satellite is
Covering the area to be transmitted of the correction information, the ionospheric correction data corresponding to the points specified by latitude and longitude are transmitted for each point at a predetermined interval,
The terminal
Sequentially receiving ionospheric correction data for each point transmitted from the second satellite;
When the number of ionospheric correction data received is a predetermined value or more,
For ionosphere correction data of unreceived points, interpolation is performed using the ionosphere correction data of other received points,
A satellite positioning system, wherein positioning is performed by correcting positioning information received from the first satellite based on the received ionosphere correction data and the interpolated ionosphere correction data. The terminal
Further, the ionosphere correction data is sequentially received, and the interpolated ionosphere correction data is updated with the received ionosphere correction data.
When the number of newly received ionospheric correction data exceeds the specified value,
Interpolate the ionosphere correction data of unreceived points using ionosphere correction data of other received points,
The satellite positioning system according to claim 1, wherein positioning is performed by correcting the received positioning information on the basis of received ionosphere correction data and newly interpolated ionosphere correction data. The terminal
Further, the ionosphere correction data is sequentially received, and the interpolated ionosphere correction data is updated with the received ionosphere correction data.
When ionospheric correction data corresponding to all points covering the transmission target area is received,
The satellite positioning system according to claim 2, wherein positioning is performed by correcting the received positioning information based on the received ionospheric correction data. Positioning is performed by receiving the positioning information from a first satellite that transmits positioning information for positioning and receiving the correction information from a second satellite that transmits correction information for correcting the positioning information. A terminal,
The correction information is
Includes ionospheric correction data for correcting radio wave delay in the ionosphere,
The terminal
Receiving the positioning information from the first satellite as appropriate;
From the second satellite, the area to be transmitted of the correction information is covered, and the ionospheric correction data transmitted for each point specified by latitude and longitude are sequentially received,
When the number of ionospheric correction data received is a predetermined value or more,
For ionosphere correction data of unreceived points, interpolation is performed using the ionosphere correction data of other received points,
A terminal that performs positioning by correcting positioning information received from the first satellite based on the received ionosphere correction data and the interpolated ionosphere correction data. Further, the ionosphere correction data is sequentially received, and the interpolated ionosphere correction data is updated with the received ionosphere correction data.
When the number of newly received ionospheric correction data exceeds the specified value,
Interpolate the ionosphere correction data of unreceived points using ionosphere correction data of other received points,
The terminal according to claim 4, wherein positioning is performed by correcting the received positioning information based on the received ionosphere correction data and the newly interpolated ionosphere correction data. Further, the ionosphere correction data is sequentially received, and the interpolated ionosphere correction data is updated with the received ionosphere correction data.
When ionospheric correction data corresponding to all points covering the transmission target area is received,
The terminal according to claim 5, wherein positioning is performed by correcting the received positioning information based on the received ionospheric correction data. Positioning is performed by receiving the positioning information from a first satellite that transmits positioning information for positioning and receiving the correction information from a second satellite that transmits correction information for correcting the positioning information. In a terminal, a method for receiving and processing ionospheric correction data included in the correction information for correcting radio wave delay in the ionosphere,
The terminal
Appropriately receiving the positioning information from the first satellite;
Sequentially receiving the ionospheric correction data transmitted for each point specified by the latitude and longitude, covering an area from which the correction information is to be transmitted from the second satellite;
When the number of ionospheric correction data received is a predetermined value or more,
Interpolating the ionosphere correction data of unreceived points using the ionosphere correction data of the other received points;
Correcting the positioning information received from the first satellite based on the received ionosphere correction data and the interpolated ionosphere correction data, and positioning,
An ionospheric correction data reception processing method characterized by comprising: The terminal
Further, sequentially receiving the ionosphere correction data, and updating the interpolated ionosphere correction data with the received ionosphere correction data;
When the number of newly received ionospheric correction data exceeds the specified value,
Interpolating the ionosphere correction data of unreceived points using the ionosphere correction data of other received points;
Based on the received ionosphere correction data and the newly interpolated ionosphere correction data, correcting the received positioning information and positioning,
The ionospheric correction data reception processing method according to claim 7, further comprising: The terminal
Further, sequentially receiving the ionosphere correction data, and updating the interpolated ionosphere correction data with the received ionosphere correction data;
When ionospheric correction data corresponding to all points covering the transmission target area is received,
Based on the received ionospheric correction data, correcting the received positioning information and positioning,
The ionospheric correction data reception processing method according to claim 8, further comprising:   An ionosphere correction data reception processing program for causing a computer to execute the ionosphere correction data reception processing method according to any one of claims 7 to 9.

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