JP2004184380A - Correction information acquiring device and program for allowing computer to perform processing in correction information acquiring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a correction information acquiring device capable of acquiring correction information at a prescribed timing, while keeping constant the accuracy of GPS positioning, and reducing the communication cost. <P>SOLUTION: This correction information acquiring device for acquiring the correction information from a base station at a prescribed timing is constituted by having a constitution having a correction information management means for managing the correction information acquired from the base station, a calculation means for calculating an independent positioning value based on position information received from a satellite and calculating a corrected positioning value based on the correction information, a judgement means for judging whether the difference between the corrected positioning value and the independent positioning value exceeds a prescribed value or not, and an information acquiring means for acquiring the correction information from the base station based on the determination result by the determination means. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a correction information acquisition apparatus and method, and in particular, to a correction positioning method (DGPS (Differential Global Positioning System)) that uses correction information for GPS (Global Positioning System) positioning, to obtain the correction information from a base station. And a correction information acquisition device.
[0002]
Further, the present invention relates to a program for causing a computer to perform the processing in the correction information obtaining method.
[0003]
[Prior art]
2. Description of the Related Art Conventionally, there is a GPS system in which a mobile terminal having an application for performing GPS positioning such as car navigation acquires position information from GPS satellites and calculates GPS positioning based on the position information. In such a GPS system, an error occurs in the position information obtained from the GPS satellites. Therefore, the mobile terminal obtains correction information for correcting the error from the base station every predetermined interval or every time the GPS positioning is calculated. , Accurate GPS positioning is calculated. The correction information is determined by comparing the known position of the base station determined in advance by the base station with the positioning information calculated by the base station to determine an error. Based on the determination result, the DGPS correction information is determined. Is generated as
[0004]
When this DGPS correction information is transmitted to each mobile terminal, a method such as being transmitted on an FM broadcast or transmitted via a mobile phone is used. For example, when the same GPS correction information is used in all mobile terminals within a wide range, a method of transmitting the information over FM broadcasting is used, while DGPS correction information corresponding to the position of each mobile terminal is required. In this case, a method is used in which the GPS correction information is transmitted to each mobile terminal via a mobile phone.
[0005]
In addition, as a conventional technique, an error is determined by comparing a known position of a reference station in which a clear position is determined in advance with a single positioning result at the reference station, a correction value of the position is obtained, and the obtained correction value is calculated. A method of distributing to each terminal is described (for example, see Patent Document 1).
[0006]
Further, as a conventional technique, in order to reduce communication cost, in the corrected positioning method (DGPS), the next positioning error is transmitted only when the difference value from the previously transmitted positioning error exceeds a predetermined value. (For example, see Patent Document 2).
[0007]
[Patent Document 1]
JP-A-7-140223
[Patent Document 2]
JP, 2002-214324, A
[Problems to be solved by the invention]
However, even if the GPS correction information is the GPS correction information acquired in the past, there is often no problem in calculating the GPS positioning. For example, the mobile phone always calculates a predetermined interval or the GPS positioning while always connected. Since the GPS correction information is acquired from the base station every time, there is a problem that an unnecessary communication cost is required.
[0010]
In a conventional GPS system, there is a system in which a mobile terminal independently receives position information from a GPS satellite and calculates GPS positioning without acquiring correction information from a base station. In many cases, only the position information includes an error that cannot be corrected by the mobile terminal, and there has been a problem that it is not possible to calculate a highly accurate GPS positioning.
[0011]
Accordingly, an object of the present invention is to provide a computer with a correction information acquisition apparatus and a correction information acquisition method capable of acquiring correction information at a predetermined timing while keeping the accuracy of GPS positioning constant and reducing communication costs. Is to provide a program for
[0012]
[Means for Solving the Problems]
To solve the above problems, the present invention is a correction information acquisition device that acquires correction information from the base station at a predetermined timing, correction information management means that manages the correction information obtained from the base station, Calculating a single positioning value based on the position information received from the satellite, calculating means for calculating a corrected positioning value based on the correction information, a difference between the corrected positioning value and the single positioning value exceeds a predetermined value A determination unit for determining whether or not the base station is present, and an information acquisition unit for acquiring correction information from the base station based on a determination result by the determination unit.
[0013]
In such a correction information acquisition device, the correction information acquired from the base station is managed, the single positioning value is calculated based on the position information received from the satellite, and the correction positioning value is calculated based on the correction information. By determining whether the difference between the corrected positioning value and the single positioning value exceeds a predetermined value, and acquiring correction information from the base station based on the determination result, while keeping the accuracy of the GPS positioning constant, When it is determined that the correction information is old, the correction information is acquired, and the communication cost can be reduced.
[0014]
Further, in order to solve the above problems, the present invention can also be a method for acquiring correction information, a program for causing a computer to perform processing in the method, and a recording medium on which the program is recorded.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0016]
FIG. 1 is a configuration diagram of a GPS system in a correction information acquisition device according to an embodiment of the present invention. In FIG. 1, a GPS system 1 includes a mobile terminal 10 which is a correction information acquisition device for acquiring correction information, and a plurality of GPS satellites 20 (here, four GPS satellites 20) to which position information of the mobile terminal 10 is transmitted. 20a to 20d), and a DGPS base station that provides the mobile terminal 10 with correction information calculated based on the position information acquired from the GPS satellites 20 and the position information of each mobile terminal 10 determined in advance. 30.
[0017]
The components of the mobile terminal 10 shown in FIG. 1 are controlled by a CPU (central processing unit). The CPU performs a process according to the correction information acquisition method in the mobile terminal 10 according to a program stored in the memory unit. The mobile terminal 10 mainly includes an antenna 40 for receiving position information from the GPS satellite 20, an antenna 42 for communicating with the DGPS base station 30, and an installer for installing a program for executing correction information acquisition processing. 11, a display control processing unit 12 for controlling display and input / output of data relating to processing in the GPS system 1, a satellite communication control processing unit 13 for controlling reception of position information from a GPS satellite 20, and a DGPS base station 30. A correction information acquisition processing unit 14 for acquiring correction information from the GPS information processing unit; a positioning calculation processing unit 15 for calculating GPS positioning alone based on the position information received from the GPS satellite 20 and calculating DGPS positioning based on the correction information; , A comparison processing unit 16 that compares GPS independent positioning with DGPS positioning, and correction information acquired from the DGPS base station 30 Composed of the correction information DB17 to store.
[0018]
The display control processing unit 12 has a display unit such as a display, and controls display data to cause the display unit to display the data. The display control processing unit 12 controls an input unit such as a touch panel and input keys and an output unit such as a speaker that performs audio output, and controls input and output of data. The satellite communication control processing unit 13 has a communication unit for receiving position information from the GPS satellite 20 via the antenna 40. The installer 11 reads the program from the recording medium 50 on which the program for realizing the correction information acquisition method according to the embodiment of the present invention is recorded, and stores the read program in, for example, an auxiliary storage device. install.
Then, when a process in a selection input method described later is started, the CPU starts the process according to the program installed in the auxiliary storage device. The recording medium 50 may be a computer-readable medium such as a ROM as a medium for storing the program.
[0019]
The correction information acquisition processing unit 14 acquires correction information from the DGPS base station 30 via the antenna 42, and stores the acquired correction information in the correction information DB 17. The positioning calculation processing unit 15 calculates the GPS positioning alone based on the position information received from the GPS satellite 20, and calculates the DGPS positioning based on the correction information stored in the correction information DB 17. The comparison processing unit 16 compares the GPS positioning calculated by the positioning calculation processing unit 15 with the DGPS positioning, and determines whether or not the value is larger than a set value. The comparison processing unit 16 determines whether the error of the correction information used in the DGPS positioning is large based on the comparison result, that is, whether the acquired correction information is old and it is necessary to newly acquire the correction information. The correction information stored in the correction information DB 17 will be described in detail with reference to FIG.
[0020]
The DGPS base station 30 is a server computer, and each component is controlled by a CPU. The DGPS base station 30 mainly controls an antenna 41 for receiving position information from the GPS satellite 20, an antenna 43 for communicating with the mobile terminal 10, and a reception of position information from the GPS satellite 20. A satellite communication control processing unit 31, a correction information provision processing unit 32 for providing correction information based on a request from the mobile terminal 10, and a DGPS positioning calculation based on the position information and the correction information from the mobile terminal 10. A DGPS positioning calculation processing unit 33, a correction information calculation processing unit 34 that calculates correction information based on the position information received from the GPS satellite 20, a known position of the base station that has been determined in advance, and the like. It comprises a correction information DB 35 for storing information and a user information DB 36 for storing user information of the mobile terminal 10.
[0021]
The satellite communication control processing unit 31 controls reception of position information from the GPS satellite 20 via the antenna 41. The correction information provision processing unit 32 provides the correction information stored in the correction information DB 35 corresponding to the predetermined mobile terminal 10 via the antenna 43. The DGPS positioning calculation processing unit 33 calculates the DGPS positioning based on the position information received from the mobile terminal 10 and the correction information stored in the correction information DB 35. The correction information calculation processing unit 34 determines a position of the GPS satellite 20 at a predetermined time, a pseudo distance (ρ1 to ρ4) between the GPS satellite 20 and the mobile terminal 10 received from the mobile terminal 10, and a base determined in advance. Correction information that is a pseudo distance correction value is calculated based on the known position of the station, and the calculated DGPS correction information is stored in the correction information DB 35.
[0022]
The DGPS positioning calculation processing unit 33 calculates DGPS positioning of the mobile terminal 10 in response to a request from the mobile terminal 10, and the correction information providing processing unit 32 calculates the DGPS positioning calculated by the mobile terminal 10. May be provided.
[0023]
The mobile terminal 10 can be applied to any terminal having the GPS positioning function or communication function, such as a mobile phone or a portable computer. In addition, an existing terminal having a GPS positioning function or communication function can be used. Applicable even when externally attached.
[0024]
Note that the above communication function is applicable as long as each mobile terminal 10 can communicate with the DGPS base station 30 while moving. For example, communication means such as a mobile phone and a modem or a wireless LAN may be used. May be.
[0025]
Next, a correction information acquisition processing procedure in the mobile terminal 10 will be described. FIG. 2 is a flowchart for explaining the correction information acquisition process. In FIG. 2, first, in the processing of step S10, the correction information acquisition processing 14 of the mobile terminal 10 acquires the latest correction information from the DGPS base station 30. In the processing of step S11, the correction information acquisition processing 14 stores the acquired correction information in the correction information DB 17. In the process of step S12, the positioning calculation processing unit 15 calculates the GPS single positioning of the mobile terminal 10 based on the position information from the GPS satellite 20 received by the satellite communication control processing unit 13. In the process of step S13, the positioning calculation processing unit 15 calculates DGPS positioning based on the correction information stored in the correction information DB17.
[0026]
In the processing of step S14, the comparison processing unit 16 compares the GPS single positioning calculation result with the DGPS positioning calculation result. In the processing of step S15, the comparison processing unit 16 determines whether or not the comparison result between the GPS single positioning calculation result and the DGPS positioning calculation result is equal to or smaller than a set value. If the comparison result is equal to or smaller than the set value in the process of step S15, in the process of step S16, the comparison processing unit 16 determines that the correction information used in the DGPS positioning calculation is not old and determines the DGPS positioning calculation result. Result. In the processing of step S18, the display control processing unit 12 performs processing such as using the DGPS positioning calculation result in the application program and displaying the result on the display unit, and repeats the processing from step 12.
[0027]
If the comparison result is not equal to or smaller than the set value in the process of step S15, in the process of step S17, the comparison processing unit 16 determines that the correction information used in the DGPS positioning calculation is old, and determines the positioning result of the GPS single positioning. Result. In the processing of step S19, the display control processing unit 12 performs processing such as displaying the result on the display unit using the GPS-only positioning calculation result in the application program, and repeating the processing from step 10 to obtain the latest correction information. I do.
[0028]
Next, the comparison process shown in step S15 will be described. FIG. 3 is a diagram for explaining the comparison process. The comparison processing unit 16 determines whether or not the comparison result between the GPS-only positioning calculation result and the DGPS positioning calculation result is equal to or smaller than a set value by the method shown in FIG. In FIG. 3, whether the DGPS positioning position is within the circle of the single positioning error circle 60 generated with the set value as the diameter centering on the single positioning position X of the GPS single positioning calculated by the positioning calculation processing unit 15. Is determined. For example, when the calculation result of the DGPS positioning is the DGPS positioning position A, since it is within the circle of the single positioning error circle 60, it is determined that there is no error in the DGPS positioning calculation result. That is, it is determined that the correction information used in the DGPS positioning calculation is not old, and the correction information can be used for the subsequent DGPS positioning calculation. On the other hand, when the calculation result of the DGPS positioning is the DGPS positioning position B, since the single positioning error circle 60 is outside the circle, it is determined that the error of the DGPS positioning calculation result is large. That is, it is determined that the correction information used in the DGPS positioning calculation is old, and a process of acquiring the latest correction information is performed.
[0029]
The setting value indicating the diameter of the single positioning error circle 60 is a value set in advance in consideration of the communication function of the GPS system 1, and the user of the mobile terminal 10 can change the setting.
[0030]
Next, the correction information, the GPS single positioning calculation result, and the DGPS positioning calculation result will be described. FIG. 4 is a diagram illustrating a relationship between the pseudo distance correction value of the correction information and the correction value change amount. In FIG. 4, the vertical axis indicates the correction value, and the horizontal axis indicates the time, showing the relationship between the pseudo distance correction value and the correction value change amount. First, the pseudo distances ρ1 to ρ4 shown in FIG. 1 are converted into four GPS satellites 20 by the satellite communication control processing unit 31 of the GPS base station 30 and the satellite communication control processing unit 13 of the mobile terminal 10 at the time t when the GPS positioning is performed. (20a to 20d). The pseudorange ρ1 (t) is the distance between the GPS satellite 20a and the mobile terminal 10, the pseudorange ρ2 (t) is the distance between the GPS satellite 20b and the mobile terminal 10, and the pseudorange ρ3 (t). Is the distance between the GPS satellite 20c and the mobile terminal 10, and the pseudo distance ρ4 (t) is the distance between the GPS satellite 20d and the mobile terminal 10. On the basis of these pseudo distances ρ1 (t) to ρ4 (t), the latitude la, the longitude lo, and the altitude h, which are the results of the GPS independent positioning calculation, are calculated.
[0031]
Further, the pseudo distance correction value and the correction value change amount of the correction information acquired from the DGPS base station 30 by the correction information acquisition processing unit 14 are as follows, assuming that the time when the correction information is generated is t0. The pseudo distance correction value ρ1 ′ (t0) is calculated by the GPS satellite 20
a and the pseudo-range correction value ρ2 ′ (t0) between the GPS satellite 20
b and the pseudo-range correction value ρ3 ′ (t0) between the GPS satellite 20
c, the pseudo-range correction value ρ4 ′ (t0) is the GPS satellite 20
The value is a pseudo distance correction value between d and d. The correction value change amount Δρ1 ′ (t0) is the change amount of the pseudo distance correction value with the GPS satellite 20a, and the correction value change amount Δρ2 ′ (t0) is the change of the pseudo distance correction value with the GPS satellite 20b. The amount of change Δρ3 ′ (t0) is the amount of change of the pseudo distance correction value with the GPS satellite 20c, and the amount of change Δρ4 ′ (t0) is the pseudo distance correction value with the GPS satellite 20d. Is the amount of change.
[0032]
Based on the correction information, the correction values ρ1 ′ (t), ρ2 ′ (t), ρ3 ′ (t), and ρ4 ′ (t) of the GPS satellites 20a to 20d at the time t are as follows: 4) Calculated by equation. Correction value ρ1 ′ (t) = ρ1 ′ (t0) + Δρ1 ′ (t−t0) (1) for the GPS satellite 20a, correction value ρ2 ′ (t) = ρ2 ′ (t0) + Δρ2 ′ (t−) for the GPS satellite 20b t0) (2), correction value ρ3 ′ (t) = ρ3 ′ (t0) + Δρ3 ′ (t−t0) (3) for the GPS satellite 20c, correction value ρ4 ′ (t) = ρ4 ′ (t0) for the GPS satellite 20d ) + Δρ4 ′ (t−t0) (4).
[0033]
The pseudo distances ρ1c (t), ρ2c (t), ρ3c (t), and ρ4c (t) corrected by the positioning calculation processing unit 15 of the mobile terminal 10 are calculated by the following equations (5) to (8). . The pseudo distance ρ1c (t) to the GPS satellite 20a = ρ1 (t) + ρ1 ′ (t) (5), and the pseudo distance ρ2c (t) to the GPS satellite 20b = ρ2 (t) + ρ2 ′ (t) (6), pseudo distance ρ3c (t) = 3 (t) + ρ3 ′ (t) (7) with the GPS satellite 20c, pseudo distance ρ4c (t) = ρ4 (t) + ρ4 with the GPS satellite 20d '(T) (8). Note that the latitude lac, longitude loc, and altitude hc, which are the DGPS positioning calculation results based on the correction information, are calculated by the above equations (5) to (8).
[0034]
The error between the GPS-only positioning calculation result (latitude la, longitude lo, altitude h) and the DGPS positioning calculation result (latitude lac, longitude loc, altitude hc) occurs because the pseudo-range values on which the calculation is based are different. I do. This error increases as the time (t-t0) increases, that is, as the correction information gets older, as shown by the above equations (1) to (4) and the deviation x from the actual one in FIG. Therefore, when the error between the GPS single positioning calculation result and the DGPS positioning calculation result is equal to or more than a predetermined value, the correction information used for calculating the DGPS positioning becomes old, and it is necessary to acquire the latest correction information. You can judge.
[0035]
Next, the correction information stored in the correction information DB 17 of the mobile terminal 10 will be described. FIG. 5 is a diagram illustrating a table stored in the correction information DB. The table 170 illustrated in FIG. 5 stores the correction information acquired by the correction information acquisition processing unit 14. The table 170 stores the date and time when the correction information was generated, the GPS satellite number, the pseudo distance correction value for the GPS satellite, and the correction value change amount. For example, the table 170 includes a pseudo distance correction value “ρ1 ′” and a correction value change amount “Δρ1 ′” for the date “August 7, 2002 13:20:00” and the GPS satellite number “20a”. Is stored.
[0036]
Next, a table used in the comparison processing of the comparison processing unit 16 will be described. FIG. 6 is a diagram illustrating a table used for the comparison processing. The table 160 shown in FIG. 6 stores the GPS single positioning calculation result and the DGPS positioning calculation result calculated by the positioning calculation processing unit 15. The table 160 stores the latitude, longitude, and altitude of the GPS-only positioning calculation result and the latitude, longitude, and altitude of the DGPS positioning calculation result. For example, in the table 160, the latitude “35 ° 34′25.81 ″”, the longitude “135 ° 39′33.25 ″”, the altitude “25.1m” of the GPS-only positioning calculation result, and the DGPS positioning calculation result The latitude “35 ° 34′25.87 ″”, the longitude “135 ° 39′33.17 ″”, and the altitude “25.4m” are stored.
[0037]
Next, an example of a screen displayed on the mobile terminal 10 will be described. FIG. 7 is a diagram illustrating an example of a screen displayed on the mobile terminal. Screen 100 shown in FIG. 7 is a screen displayed on the display of mobile terminal 10 by display control processing unit 12. The screen 100 includes a selection area 101 for selecting valid / invalid of the DGPS positioning, a selection area 102 for selecting valid / invalid of the saving mode, and an input for inputting the accuracy which is a set value of the GPS positioning. The area 103 is displayed. For example, when performing DGPS positioning using the correction information, the validity of the selection area 101 is selected. Further, when the function of saving the communication fee in the mobile terminal 10 is selected, that is, when the above-described correction information acquisition processing is performed, the validity of the selection area 102 is selected. In addition, when setting a value serving as a criterion for determining a difference between the DGPS positioning calculation result and the GPS positioning calculation result in order to determine the acquisition of the latest correction information, the set value is input to the input area.
[0038]
In this manner, the mobile terminal 10 compares the GPS-only positioning calculation result with the DGPS positioning calculation result calculated based on the correction information, determines whether the comparison result is equal to or greater than a set value, and sets the comparison result to the set value. By obtaining the latest correction information from the GPS base station 30 when the value is equal to or more than the value, it is possible to obtain the correction information when the error exceeds the set value while maintaining the accuracy of the GPS positioning constant. Communication cost can be reduced.
(Supplementary Note 1) A correction information acquisition device that acquires correction information from a base station at a predetermined timing,
Correction information management means for managing the correction information obtained from the base station,
Calculating means for calculating a single positioning value based on the position information received from the satellite, and calculating a corrected positioning value based on the correction information;
Determining means for determining whether the difference between the corrected positioning value and the single positioning value exceeds a predetermined value,
An information acquisition unit for acquiring correction information from the base station based on a result of the determination by the determination unit.
(Supplementary Note 2) The information acquiring means acquires correction information from the base station when it is determined that the difference between the corrected positioning value and the single positioning value exceeds a predetermined value based on the determination result of the determining means. 3. The correction information acquiring apparatus according to claim 1, wherein
(Supplementary note 3) The correction information according to Supplementary note 1 or 2, wherein the correction information includes a correction value of a pseudo distance between the satellite and the correction information acquisition device, and a change amount of the correction value. Acquisition device.
(Supplementary Note 4) The correction information acquisition according to any one of Supplementary notes 1 to 3, wherein the calculating unit calculates a corrected positioning value based on the correction value of the pseudo distance and a change amount of the correction value. apparatus.
(Supplementary Note 5) Output control for selecting the single positioning value and performing output processing when it is determined that the difference between the corrected positioning value and the single positioning value exceeds a predetermined value based on the determination result by the determining means. Having means,
5. The correction information obtaining apparatus according to claim 1, wherein the information obtaining unit obtains correction information from the base station after the output processing is performed.
(Supplementary Note 6) The output control means selects and outputs the corrected positioning value when the difference between the corrected positioning value and the single positioning value is determined to be equal to or less than a predetermined value based on the determination result of the determining means. Do the processing,
6. The correction information acquisition apparatus according to claim 5, wherein the information acquisition unit suppresses acquisition of correction information from the base station after the output processing is performed.
(Supplementary note 7) The correction information acquiring device according to supplementary note 5 or 6, wherein the output control means displays a screen for setting the predetermined value.
(Supplementary Note 8) A correction information acquisition method for acquiring correction information from a base station at a predetermined timing,
A correction information management procedure for managing the correction information obtained from the base station,
A calculation procedure of calculating a single positioning value based on the position information received from the satellite, and calculating a corrected positioning value based on the correction information,
A determination procedure for determining whether the difference between the corrected positioning value and the single positioning value exceeds a predetermined value,
An information acquisition step of acquiring correction information from the base station based on a result of the determination.
(Supplementary Note 9) A program for causing a computer to perform processing in a correction information acquisition method of acquiring correction information from a base station at a predetermined timing,
A correction information management procedure for managing the correction information obtained from the base station,
A calculation procedure of calculating a single positioning value based on the position information received from the satellite, and calculating a corrected positioning value based on the correction information,
A determination procedure for determining whether the difference between the corrected positioning value and the single positioning value exceeds a predetermined value,
A program for obtaining correction information from the base station based on a result of the determination.
(Supplementary Note 10) A recording medium storing a program for causing a computer to perform a process in a correction information acquisition method of acquiring correction information from a base station at a predetermined timing,
A correction information management procedure for managing the correction information obtained from the base station,
A calculation procedure of calculating a single positioning value based on the position information received from the satellite, and calculating a corrected positioning value based on the correction information,
A determination procedure for determining whether the difference between the corrected positioning value and the single positioning value exceeds a predetermined value,
A recording medium storing a program, comprising: an information acquisition step of acquiring correction information from the base station based on a result of the determination.
[0039]
【The invention's effect】
As described above, according to the present invention, the correction information acquired from the base station is managed, the single positioning value is calculated based on the position information received from the satellite, and the correction positioning value is calculated based on the correction information. It is determined whether or not the difference between the corrected positioning value and the single positioning value exceeds a predetermined value, and correction information is obtained from the base station based on the determination result. The correction information is acquired at the timing of (1), and the communication cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a GPS system in a correction information acquisition device according to an embodiment of the present invention.
FIG. 2 is a flowchart for explaining correction information acquisition processing.
FIG. 3 is a diagram illustrating a comparison process.
FIG. 4 is a diagram illustrating a relationship between a pseudo distance correction value of correction information and a correction value change amount.
FIG. 5 is a diagram showing a table stored in a correction information DB.
FIG. 6 is a diagram showing a table used for comparison processing.
FIG. 7 is a diagram illustrating an example of a screen displayed on a mobile terminal.
[Explanation of symbols]
Reference Signs List 1 GPS system 10 Mobile terminal 11 Installer 12 Display control processing unit 13, 31 Satellite communication control processing unit 14 Correction information acquisition processing unit 15 Positioning calculation processing unit 16 Comparison processing unit 17, 35 Correction information DB
20, 20a to 20d GPS satellite 30 DGPS base station 32 Correction information providing processing unit 33 DGPS positioning calculation processing unit 34 Correction information calculation processing unit 36 User information DB
40 to 43 Antenna 50 Recording medium

Claims (5)

A correction information acquisition device that acquires correction information from a base station at a predetermined timing,
Correction information management means for managing the correction information obtained from the base station,
Calculating means for calculating a single positioning value based on the position information received from the satellite, and calculating a corrected positioning value based on the correction information;
Determining means for determining whether the difference between the corrected positioning value and the single positioning value exceeds a predetermined value,
An information acquisition unit for acquiring correction information from the base station based on a result of the determination by the determination unit. The information obtaining means obtains correction information from the base station when it is determined that a difference between the corrected positioning value and the single positioning value exceeds a predetermined value based on a determination result of the determining means. The correction information acquisition device according to claim 1, wherein When it is determined that the difference between the corrected positioning value and the single positioning value exceeds a predetermined value based on the result of the determination by the determining unit, an output control unit that selects the single positioning value and performs an output process. ,
3. The correction information acquiring apparatus according to claim 1, wherein the information acquiring unit acquires the correction information from the base station after the output processing is performed. The output control means, when it is determined that the difference between the corrected positioning value and the single positioning value is equal to or less than a predetermined value according to the determination result of the determining means, performs the output processing by selecting the corrected positioning value,
4. The correction information acquisition device according to claim 3, wherein the information acquisition unit suppresses acquisition of correction information from the base station after the output processing is performed. A program for causing a computer to perform processing in a correction information obtaining method of obtaining correction information from a base station at a predetermined timing, and a correction information management procedure for managing the correction information obtained from the base station,
A calculation procedure of calculating a single positioning value based on the position information received from the satellite, and calculating a corrected positioning value based on the correction information,
A determination procedure for determining whether the difference between the corrected positioning value and the single positioning value exceeds a predetermined value,
A program for obtaining correction information from the base station based on a result of the determination.

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