JP2008026137A - Communication base station, its control method, its control program, recording medium, and positioning apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication base station etc. capable of providing a code phase at the communication base station for positioning apparatuses which can communicate with the communication base station only in the case that the condition that the use of the code phase at the communication base station is appropriate is satisfied. <P>SOLUTION: The communication base station 40 comprises a propagation time evaluation means for determining whether the propagation time required for communication radio waves to propagate between the communication base station 40 and a positioning apparatus 20 lies within a prescribed allowable range of time or not; a phase code computation means for computing a code phase of each satellite signal; a difference computation means for computing the difference between the code phase computed by the communication base station 40 and a code phase on the positioning side; a difference evaluation means for determining whether the difference lies within a multipath influence range, a range in the case that the difference is under the influence of multipath; and a correction value transmission means for transmitting a code phase computed by the communication base station 40 to the positioning apparatus 20 in the case that the difference evaluation means has determined that the difference lies within the multipath influence range. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a communication base station that assists positioning, a control method thereof, a control program and recording medium thereof, and a positioning device.

Conventionally, a positioning system that measures the current position of a positioning device using a satellite positioning system (SPS), which is a satellite navigation system using an artificial satellite, has been put into practical use (see Japanese Patent Application Laid-Open No. 10-337772 and the like).
However, the positioning device may receive radio waves in a state where indirect waves (hereinafter referred to as multipaths) in which radio waves from satellites are reflected on buildings or the like interfere with the direct waves. The multipath is reflected on the building and the like, and the arrival to the positioning device is delayed. As a result of the multipath directly interfering with the wave, the correlation peak value shifts, and there is a problem that a large error occurs in the positioning calculation. In this specification, an environment in which multipath is likely to occur is called a multipath environment.
In this regard, for positioning devices integrated with mobile phones, the location of the communication base station is used when it is determined that the location of the communication base station is higher than the location calculated using satellite radio waves. The technique which performs is proposed (for example, patent document 1).
It is also conceivable to use the code phase of the C / A (Coarse and Acquisition) code calculated by the communication base station as the code phase of the positioning device.
JP 2006-109355 A

However, since the position of the communication base station is fixed, the position output by the technique of Patent Document 1 may be inconvenient when the positioning device integrated with the mobile phone is moving.
In addition, since the code phase of the C / A code calculated by the communication base station should be different from the true code phase at the position of the positioning device, only the reason that the positioning device can communicate with the communication base station, When the code phase in the communication base station is uniformly used as the code phase in the positioning device, there is a problem that the accuracy of the positioning position may be deteriorated.

  Therefore, the present invention provides the code phase in the communication base station only when the positioning device capable of communicating with the communication base station satisfies a condition that it is appropriate to use the code phase in the communication base station. It is an object of the present invention to provide a communication base station, a control method thereof, a control program and recording medium thereof, and a positioning device.

  According to the first aspect of the present invention, there is provided a communication base station that can communicate with a positioning device that uses satellite signals from a plurality of positioning satellites and is located at a fixed position. A propagation time calculating means for calculating a propagation time during which a communication radio wave propagates between, a propagation time evaluating means for determining whether or not the propagation time is within a predetermined time allowable range, and a satellite for receiving the satellite signal Signal receiving means, code phase calculating means for calculating the code phase of each satellite signal, positioning side code phase receiving means for receiving a positioning side code phase that is a code phase of each satellite signal calculated by the positioning device; A difference calculating means for calculating a difference between the code phase calculated by the communication base station and a positioning-side code phase, and the difference is affected by multipath. When the difference evaluation unit determines whether the difference is within the multipath influence range by the difference evaluation unit that determines whether or not the difference range is within the multipath influence range, the communication base station calculates It is achieved by a communication base station comprising correction value transmission means for transmitting the code phase to the positioning device.

According to the configuration of the first invention, the communication base station can determine whether or not the propagation time is within the time allowable range by the propagation time evaluation means. For this reason, the communication base station recognizes whether the positioning device is not only in the communication area (cell) of the communication base station but also in a position close to the communication base station. be able to.
And the said communication base station can calculate the difference of the said code phase and the positioning side code phase which the said communication base station calculated by the said difference calculation means. Here, even if the communication base station and the positioning device are close to each other, since the true position is usually different, the difference includes a difference due to a difference in the true position, There is a possibility that a difference due to an error other than multipath and a difference due to an error due to multipath are included.
And the said communication base station can judge whether the said difference is in a multipath influence range by the said difference evaluation means. That is, the communication base station not only has a difference between the code phase calculated by the communication base station and the positioning-side code phase, but also whether the difference is within the multipath influence range. Can be determined.
Since the communication base station has the correction value transmission means, the code phase calculated by the communication base station when the difference evaluation means determines that the difference is within the multipath influence range. Can be transmitted to the positioning device.
As described above, since the communication base station can recognize whether or not the positioning device is in a position close to the communication base station, the positioning device is in a position close to the communication base station. And the code phase calculated by the communication base station can be transmitted to the positioning device when it is determined that the difference is within the multipath influence range. If the positioning device satisfies the condition that it is in a position very close to the communication base station, the positioning side code phase is not affected by multipath, and the code phase calculated by the communication base station and Should be nearly identical. For this reason, it is appropriate for the positioning device to use the code phase calculated by the communication base station for positioning. In addition, instead of using the positioning side code phase calculated by the positioning device using a multipath signal, it is appropriate to use the code phase calculated by the adjacent communication base station for positioning. is there. That is, the positioning accuracy of the positioning device is highly likely to improve.
Accordingly, the code phase in the communication base station can be provided only to a positioning device that can communicate with the communication base station, when a condition that is appropriate to use the code phase in the communication base station is satisfied. .

  According to a second aspect of the present invention, in the configuration of the first aspect, the allowable time range is such that the positions of the communication base station and the positioning device are close enough to be regarded as substantially the same. A communication base station characterized by being defined as a time range.

  A third invention is characterized in that, in the configuration of the second invention, the multipath influence range is defined in consideration of a distance corresponding to the time allowable range and a calculation error of the positioning side code phase. Communication base station.

  According to the configuration of the third invention, the communication base station can reliably determine whether or not the positioning side code phase is affected by multipath.

  According to the fourth aspect, the object is to communicate with a positioning device that performs positioning using satellite signals from a plurality of positioning satellites, and a communication base station located at a fixed position can communicate with the positioning device. A propagation time calculating step for calculating a propagation time for communication radio waves to propagate between, a propagation time evaluating step for the communication base station to determine whether or not the propagation time is within a predetermined time allowable range, and the communication base A satellite signal receiving step in which the station receives the satellite signal, a code phase calculating step in which the communication base station calculates a code phase of each satellite signal, and each of the communication base station calculated by the positioning device A positioning-side code phase receiving step for receiving a positioning-side code phase that is a code phase of the satellite signal; and the communication base station, the code base calculated by the communication base station. A difference calculating step for calculating a difference between a positioning phase code phase and a positioning side code phase, and whether or not the communication base station is within a multipath influence range which is a difference range when the difference is affected by a multipath. A difference evaluation step to determine; and when the communication base station determines in the difference evaluation step that the difference is within the multipath influence range, the positioning device calculates the code phase calculated by the communication base station. And a correction value transmitting step for transmitting to the communication base station.

  According to the configuration of the fourth aspect of the invention, as in the configuration of the first aspect of the invention, the condition that it is reasonable to use the code phase in the communication base station is satisfied for the positioning device that can communicate with the communication base station. The code phase at the communication base station can be provided only when

  According to a fifth aspect of the present invention, there is provided a communication base station that is capable of communicating with a positioning device that uses a satellite signal from a plurality of positioning satellites and that is located at a fixed position. A propagation time calculating step for calculating a propagation time for communication radio waves to propagate between the devices, and a propagation time evaluating step for determining whether the communication base station is within a time allowable range defined in advance. The communication base station receives the satellite signal, a satellite signal reception step, the communication base station calculates a code phase of each satellite signal, the communication base station, the positioning device A positioning side code phase receiving step for receiving a positioning side code phase, which is a code phase of each of the satellite signals calculated, and the communication base station calculates the communication base station; A difference calculating step for calculating a difference between the code phase and the positioning side code phase; and whether the communication base station is within a multipath influence range which is a difference range when the difference is affected by a multipath. A difference evaluation step for determining whether or not the communication base station calculates the code phase calculated by the communication base station when the difference evaluation step determines that the difference is within the multipath affected range. And a correction value transmitting step for transmitting to the positioning device. This is achieved by a communication base station control program.

  According to the sixth aspect of the present invention, the communication base station that is capable of communicating with a positioning device that uses satellite signals from a plurality of positioning satellites and that is located at a fixed position is capable of communicating with the computer. A propagation time calculating step for calculating a propagation time for communication radio waves to propagate between the devices, and a propagation time evaluating step for determining whether the communication base station is within a time allowable range defined in advance. A satellite signal receiving step in which the communication base station receives the satellite signal; a code phase calculating step in which the communication base station calculates a code phase of each satellite signal; and the communication base station, the positioning device A positioning-side code phase receiving step for receiving a positioning-side code phase that is a code phase of each of the satellite signals calculated; and the communication base station calculates the communication base station A difference calculating step for calculating a difference between the code phase and the positioning-side code phase, and whether the communication base station is within a multipath influence range that is a difference range when the difference is affected by a multipath. A difference evaluation step for determining whether the communication base station calculates the code phase calculated by the communication base station when the communication base station determines in the difference evaluation step that the difference is within the multipath affected range. And a correction value transmission step of transmitting to the positioning device. This is achieved by a computer-readable recording medium recording a communication base station control program.

  According to a seventh aspect of the present invention, there is provided a positioning device capable of communicating with a communication base station located at a fixed position and positioning using satellite signals from a plurality of positioning satellites, wherein the communication base station Is determined that the propagation time of the communication radio wave propagating between the positioning device is within a predetermined time allowable range, and the communication base station calculates the communication base station by receiving the satellite signal. A difference between a code phase and a positioning-side code phase that is a code phase of each satellite signal calculated by the positioning device is calculated, and further, a multipath that is a difference range when the difference is affected by a multipath When it is within the influence range, the code phase calculated by the communication base station is received, and the code phase and the positioning side code phase calculated by the communication base station are And use is accomplished by the positioning apparatus and performs positioning.

  According to the configuration of the seventh invention, the positioning device receives the code phase in the communication base station and performs positioning only when the condition that it is appropriate to use the code phase in the communication base station is satisfied. Can be used.

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
The embodiments described below are preferred specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless otherwise stated, the present invention is not limited to these embodiments.

FIG. 1 is a schematic diagram showing a positioning system 10 according to an embodiment of the present invention.
As shown in FIG. 1, the positioning system 10 includes GPS (Global Positioning System) satellites 12a, 12b, 12c, 12d, 12e, and 12f. The GPS satellites 12a and the like can transmit radio waves S1, S2, S3, S4, S5 and S6, respectively. The GPS satellites 12a and the like are examples of positioning satellites.
The positioning satellite is not limited to a GPS satellite, and may be a satellite widely used in SPS. The SPS includes, for example, Galileo and a quasi-zenith satellite in addition to GPS.
Various codes (codes) are carried on the radio wave S1 and the like. One of them is a C / A code. This C / A code is a signal having a bit rate of 1.023 Mbps and a bit length of 1,023 bits (= 1 msec). The C / A code Sca is composed of 1,023 chips. The C / A code is an example of a satellite signal.

The positioning system 10 also includes a terminal 20A and a terminal 20B. Terminal 20A and terminal 20B are collectively referred to as terminal 20.
The terminal 20 is a mobile phone having a positioning function, and can measure the current position using a C / A code. The terminal 20 is an example of a positioning device.

  For example, the terminal 20 specifies a code phase (phase) of a C / A code from three or more different GPS satellites 12a and the like, calculates a pseudo distance between each GPS satellite 12a and the terminal 15 and the pseudo-range. The current position can be measured using the distance.

FIG. 2 is a conceptual diagram illustrating an example of a positioning method.
As shown in FIG. 2, for example, it can be considered that C / A codes are continuously arranged between the GPS satellite 12 a and the terminal 20. Since the distance between the GPS satellite 12a and the terminal 20 is not necessarily an integer multiple of the length of the C / A code (about 300 kilometers (km)), there is a code fractional part C / Aa. That is, between the GPS satellite 12a and the terminal 20, there are a part that is an integral multiple of the C / A code and a fractional part. The total length of the integral multiple of the C / A code and the fractional part is the pseudorange. The terminal 20 performs positioning using pseudoranges for three or more GPS satellites 12a and the like.
In this specification, the fractional part C / Aa of the C / A code is referred to as a code phase. For example, the code phase can be indicated by the number of the 1023 chip of the C / A code, or can be indicated in terms of distance.

  The position of the GPS satellite 12a in the orbit can be calculated using the ephemeris. The ephemeris is information indicating a precise orbit of each GPS satellite 12a or the like carried on the radio wave S1 or the like. For example, if the distance between the position of the GPS satellite 12a in the orbit and the initial position Q0 (not shown) is calculated, a portion that is an integral multiple of the C / A code can be specified. Since the length of the C / A code is about 300 kilometers (km), the position error of the initial position Q0 needs to be within 150 kilometers (km).

The terminal 20 performs correlation processing including coherent processing and incoherent processing.
In the coherent process, if the coherent time is 5 msec, the terminal 20 calculates a correlation value between the C / A code and the replica C / A code that are synchronously integrated in the time of 5 msec. As a result of the coherent processing, the code phase when the correlation is obtained and the correlation value are output.
In the incoherent process, the terminal 20 calculates a correlation integrated value (incoherent value) by integrating the correlation values of the coherent results.
The code phase having the maximum correlation integrated value is the code fraction C / Aa.

The positioning system 10 also has a base station 40. The base station 40 can communicate with the terminal 20. The base station 40 is a communication base station in a mobile phone system and is located at a fixed position. The coordinates of this fixed position are known. The fixed position where the base station 40 is located is an open sky environment where there are no obstacles in the vicinity. For this reason, the base station 40 can receive the radio wave S3 as the direct wave r1 from the GPS satellite 12c, for example. The base station 40 is an example of a communication base station.
The base station 40 can mediate communication between the terminal 20 and other terminals via the dedicated line 65.
The base station 40 has a GPS receiver 42 and can receive radio waves S1 and the like from GPS satellites 12a and the like.
Then, the base station 40 can calculate the code phase of the C / A code.

Here, when there is no obstacle in the vicinity like the position of the terminal 20A, for example, the radio wave S3 reaches the terminal 20A directly as the wave r2.
On the other hand, when there are obstacles such as the buildings 13A and 13B in the vicinity like the position of the terminal 20B, for example, the radio wave S3 is reflected on the building 13B and becomes an indirect wave (multipath) r3. The terminal 20B is reached.
In the case of the multipath r3, since the propagation path is longer than that of the direct wave, the terminal 20B calculates the code phase longer than that of the direct wave. As a result, the accuracy of the positioning position is degraded.

In contrast, the base station 40 has a code phase calculated by receiving the direct wave r1 and a time (RTT (Round Trip Time)) until the communication radio wave makes a round trip between the base station 40 and the terminal 20 as a predetermined requirement. Only when the condition is satisfied, the terminal 20B performs high-precision positioning by transmitting the code phase calculated by the base station 40 in order to correct the code phase calculated by the terminal 20B under the influence of the multipath. Assistance can be provided.
Since the propagation speed of the communication radio wave is known (the speed of light), the base station 40 can calculate the distance d between the base station 40 and the terminal 20B using the RTT.
The base station 40 transmits and receives communication radio waves using, for example, four antennas (not shown). The four antennas transmit communication radio waves in four different directions, for example, east, west, north, and south, respectively, and receive communication radio waves from the terminal 20. The base station 40 is configured to be able to recognize in which direction the communicating terminal 20 is receiving communication radio waves from the antenna of the base station 40.

(Main hardware configuration of terminal 20)
FIG. 3 is a schematic diagram showing the main hardware configuration of the terminal 20.
As shown in FIG. 3, the terminal 20 has a bus 22.

A CPU (Central Processing Unit) 24, a storage device 26, and the like are connected to the bus 22. The storage device 26 is, for example, a RAM (Random Access Memory) or a ROM (Read Only Memory).
In addition, an input device 28 for inputting various information, a power supply device 30, a communication device 32, and a GPS device 34 are connected to the bus 22. The terminal 20 can receive the radio wave S1 and the like by the GPS device 34.
In addition, a display device 36 for displaying various information is connected to the bus 22.

(Main hardware configuration of base station 40)
FIG. 4 is a schematic diagram showing the main hardware configuration of the base station 40.
As shown in FIG. 4, the base station 40 has a bus 42.

A CPU 44, a storage device 46, an external storage device 48, and the like are connected to the bus 42. The external storage device 48 is, for example, an HDD (Hard Disk Drive).
The bus 42 is connected to an input device 50 for inputting various information and the like, a power supply device 52, a communication device 54, a GPS device 56, a display device 58, and a clock 60.
Note that the base station 40 can recognize which of the four antennas the specific terminal 20 is using to transmit and receive communication radio waves.
The base station 40 can measure the RTT (see FIG. 1) using the clock 60.

(About main software configuration of terminal 20)
FIG. 5 is a schematic diagram showing a main software configuration of the terminal 20.
As illustrated in FIG. 5, the terminal 20 includes a terminal control unit 100 that controls each unit, a communication unit 102 that corresponds to the communication device 32 in FIG. 3, a GPS unit 104 that corresponds to the GPS device 34, and a display that corresponds to the display device 36. Part 106 and the like.
The terminal 20 also includes a first storage unit 110 that stores various programs and a second storage unit 150 that stores various information.

As illustrated in FIG. 5, the terminal 20 stores satellite orbit information 152 in the second storage unit 150. The satellite orbit information 152 includes an almanac 152a and an ephemeris 152b.
The almanac 152a is information indicating an approximate orbit of all the GPS satellites 12a and the like (see FIG. 1). The almanac 152a can be obtained by decoding from the signal G1 or the like of any GPS satellite 12a or the like.
The ephemeris 152b is information indicating a precise orbit of each GPS satellite 12a or the like (see FIG. 1). For example, in order to acquire the ephemeris 152b of the GPS satellite 12a, it is necessary to receive, decode, and acquire the signal G1 from the GPS satellite 12a.
The terminal 20 uses the satellite orbit information 152 for positioning.

As shown in FIG. 5, the terminal 20 stores a satellite signal reception program 112 in the first storage unit 110. The satellite signal reception program 112 is a program for the control unit 100 to receive the radio wave S1 and the like from the GPS satellite 12a and the like.
Specifically, the control unit 100 refers to the almanac 152a, determines the GPS satellite 12a that can be observed at the current time, and receives the radio wave S1 and the like from the observable GPS satellite 12a. At this time, for example, the position of the base station 40 is used as the reference self-position. The terminal 20 can acquire information indicating the position of the base station 40 from the communicating base station 40.

As illustrated in FIG. 5, the terminal 20 stores a code phase calculation program 114 in the first storage unit 110. The code phase calculation program 114 is a program for the terminal control unit 100 to calculate the code phase of the C / A code for each GPS satellite 12a and the like.
For example, the terminal control unit 100 calculates a code phase CPm1 for the GPS satellite 12a, a code phase CPm2 for the GPS satellite 12b, a code phase CPm3 for the GPS satellite 12c, and a code phase CPm4 for the GPS satellite 12d.
The terminal control unit 100 stores code phase information 154 indicating the code phase CPm1 and the like in the second storage unit 150. The code phase CPm1 and the like are collectively referred to as a terminal code phase CPm.

  As illustrated in FIG. 5, the terminal 20 stores a code phase transmission program 114 in the first storage unit 110. The code phase transmission program 114 is a program for the terminal control unit 100 to transmit the code phase information 154 to the base station 40.

As illustrated in FIG. 5, the terminal 20 stores a correction information reception program 118 in the first storage unit 110. The correction information reception program 118 is a program for the terminal control unit 100 to receive the base station code phase CPb from the base station 40.
The base station code phase CPb is information provided by the base station 40 when the radio wave S1 received by the terminal 20 is multipath.
The terminal control unit 100 stores correction information 156 indicating the base station code phase CPb in the second storage unit 150.

  As illustrated in FIG. 5, the terminal 20 stores a positioning program 120 in the first storage unit 110. The positioning program 120 is a program for the terminal control unit 100 to measure the current position using the code phase information 154 and the correction information 156.

FIG. 6 is an explanatory diagram of the positioning program 120.
As illustrated in FIG. 6, for example, when the terminal controller 100 receives the ki base station code phase CPb3 only for the GPS satellite 12c, the terminal controller 100 calculates the code phase CPm1 calculated by the terminal 20 for the GPS satellites 12a, 12b, and 12d. CPm2 and CPm4 are used. For the GPS satellite 12c, the base station code phase CPb3 is used instead of the code phase CPm3.
The terminal control unit 100 measures the current position using the code phases CPm1, CPm2, CPm4, and CPf, and calculates the positioning position P.
The terminal control unit 100 stores positioning position information 158 indicating the calculated positioning position P in the second storage unit 150.

  As illustrated in FIG. 5, the terminal 20 stores a positioning position output program 122 in the first storage unit 110. The positioning position output program 122 is a program for the terminal control unit 100 to display the positioning position P on the display device 36 (see FIG. 3).

(Main software configuration of base station 40)
FIG. 7 is a schematic diagram showing a main software configuration of the base station 40.
As illustrated in FIG. 7, the base station 40 includes a control unit 200 that controls each unit, a communication unit 202 that corresponds to the communication device 54 in FIG. 4, a GPS unit 204 that corresponds to the GPS device 56, and a display that corresponds to the display device 58. A time measuring unit 208 corresponding to the unit 206 and the clock 60.
The base station 40 also includes a first storage unit 210 that stores various programs and a second storage unit 250 that stores various types of information.

  As shown in FIG. 7, the base station 40 stores satellite orbit information 252 in the second storage unit 250. The satellite orbit information 252 includes an almanac 252a and an ephemeris 252b.

As illustrated in FIG. 7, the base station 40 stores an RTT calculation program 212 in the first storage unit 210. The RTT calculation program 212 is a program for the control unit 200 to calculate the propagation time RTT for determining the communication radio wave between the base station 40 and the terminal 20. The RTT calculation program 212 and the control unit 200 are examples of propagation time calculation means.
Specifically, the control unit 200 transmits a specific frame (referred to as a base station frame) to the terminal 20, and a frame (referred to as a terminal frame) transmitted from the terminal 20 corresponding to the base station frame. Receive. Then, the RTT is calculated by measuring the transmission time of a specific base station frame and the reception time of the terminal frame corresponding to the base station frame by the timer unit 208.
As described above, the control unit 200 is configured to calculate the round trip time (RTT) in which the communication radio wave travels between the base station 40 and the terminal 20.
The control unit 200 stores RTT information 254 indicating the calculated RTT in the second storage unit 250.

As illustrated in FIG. 7, the base station 40 stores an RTT evaluation program 214 in the first storage unit 210. The RTT evaluation program 214 is a program for the control unit 200 to determine whether or not the RTT is equal to or less than a predetermined time threshold value α. The time threshold value α is, for example, 0.7 microseconds (μs). The time range below the time threshold α is an example of a time allowable range. The RTT evaluation program 214 and the control unit 200 are examples of propagation time evaluation means.
The time threshold α is defined as a time during which the control unit 200 can consider that the terminal 20 is located in a communicable area (also referred to as a cell) of the base station 40 and is sufficiently close to the base station 40. Has been. In other words, the time range defined by the time threshold value α is defined as a time range when the positions of the base station 40 and the terminal 20 are close enough to be considered to be substantially the same.
If the RTT is 0.7 microseconds (μs), the time for the communication radio wave to reach the terminal 20 from the base station 40 is half that of 0.35 microseconds (μs). Since the communication radio wave propagates at the speed of light (about 2999792456 (m / ms)), the distance between the base station 40 and the terminal 20 is about 105 meters (m). This distance is calculated when the code phase calculated by the terminal 20 is compared with the code phase calculated by the terminal 20 and the code phase calculated by the terminal 20 is determined to be affected by multipath, as will be described later. In this case, the code phase calculated by the base station 40 is transmitted to the terminal 20, and the terminal 20 defines that the code phase calculated by the base station 40 should be used for positioning.

As shown in FIG. 7, the base station 40 stores a satellite signal reception program 216 in the first storage unit 210. The satellite signal reception program 216 is a program for the control unit 200 to receive the radio wave S1 and the like from the GPS satellite 12a and the like. The satellite signal reception program 216 and the control unit 200 are examples of satellite signal reception means.
The contents of the satellite signal reception program 216 are the same as the satellite signal reception program 112 (see FIG. 5) of the terminal 20 described above.

As illustrated in FIG. 7, the base station 40 stores a code phase calculation program 218 in the first storage unit 210. The code phase calculation program 218 is a program for the control unit 200 to calculate the code phase of the C / A code for each GPS satellite 12a and the like. The code phase calculation program 218 and the control unit 200 are an example of a code phase calculation unit.
For example, the control unit 200 calculates a code phase CPb1 for the GPS satellite 12a, a code phase CPb2 for the GPS satellite 12b, a code phase CPb3 for the GPS satellite 12c, and a code phase CPb4 for the GPS satellite 12d.
If the RTT is equal to or less than the predetermined time threshold value α, the distance between the base station 40 and the terminal 20 is extremely short. The code phase can be calculated by receiving the radio wave S1 or the like from the satellite 12a or the like.
Here, since the reception environment of the radio wave S1 and the like of the base station 40 is open sky and the reception state of the radio wave S1 and the like is good, the code phase CPb1 and the like are not affected by the multipath and are extremely accurate. Is expensive. The code phase CPb1 and the like are collectively referred to as a code phase CPb.
The control unit 200 stores code phase information 258 indicating the code phase CPb1 and the like in the second storage unit 250.

As illustrated in FIG. 7, the base station 40 stores a terminal code phase reception program 220 in the first storage unit 210. The terminal code phase reception program 220 is a program for the control unit 200 to receive terminal code phase information 154 (see FIG. 5) from the terminal 20. The terminal code phase reception program 220 and the control unit 200 are examples of positioning side code phase reception means.
The control unit 200 stores the received terminal code phase information 154 in the second storage unit 250 as terminal code phase information 258.

  As illustrated in FIG. 7, the base station 40 stores a code phase difference calculation program 222 in the first storage unit 210. The code phase difference calculation program 222 is a program for the control unit 200 to calculate the difference CPdif between the base station code phase CPb1 and the like and the terminal code phase CPm1 and the like. The difference CPdif is an example of a difference. The code phase difference calculation program 222 and the control unit 200 are an example of a difference calculation unit.

FIG. 8 is an explanatory diagram of the code phase difference calculation program 222.
FIG. 8 conceptually shows a comparison of code phases.
The control unit 200 calculates a difference CPdif for each GPS satellite 12a and the like. For example, the difference between the base station code phase CPb1 for the GPS satellite 12a and the terminal code phase CPm1 for the GPS satellite 12a is calculated. Then, as shown in FIG. 8, the difference CPdif is calculated in units of c1 chip (chip) and c2 chip. This chip is a basic unit constituting the C / A code.
The control unit 200 stores the code phase difference information 260 indicating the calculated difference CPdif in the second storage unit 250.

As illustrated in FIG. 7, the base station 40 stores a code phase difference evaluation program 224 in the first storage unit 210. The code phase difference evaluation program 224 is a program for the control unit 200 to determine whether or not the difference CPdif is greater than or equal to the threshold value β. The threshold value β is, for example, one chip. When the difference CPdif is greater than or equal to the threshold value β, it can be determined that the terminal-side code phase used for calculating the difference CPdif is affected by multipath. In other words, the threshold value β is defined as a difference range when the terminal code phase is affected by multipaths.
The threshold value β or more is an example of the difference range. The code phase difference evaluation program 224 and the control unit 200 are an example of a difference evaluation unit.
When the control unit 200 determines that the RTT is equal to or less than the time threshold value α by the above RTT evaluation program, the above-described satellite signal reception program 216, code phase calculation program 218, terminal code phase reception program 220, code phase difference The operation is based on the calculation program 222 and the code phase difference evaluation program 224.

  As illustrated in FIG. 7, the base station 40 stores a correction value transmission program 226 in the first storage unit 210. The correction value transmission program 226 is a program for transmitting the base station code phase CPb1 and the like for the corresponding GPS satellite 12a and the like to the terminal 20 when the control unit 200 determines that the difference CPdif is equal to or greater than the threshold value β. is there. The correction value transmission program 226 and the control unit 200 are examples of correction value transmission means.

The positioning system 10 is configured as described above.
As described above, the base station 40 can determine whether or not the RTT is equal to or less than the threshold value α. For this reason, the base station 40 can recognize not only that the terminal 20 is in the communication area (cell) of the base station 40 but also whether the terminal 20 is in a position close to the base station 40.
Then, the base station 40 can calculate the difference CPdif between the code phase CPb calculated by the base station 40 and the terminal code phase CPm. Here, even when the base station 40 and the terminal 20 are close to each other, since the true positions of the two are usually different, the difference CPdif includes the difference due to the difference of the true position, the multipath, and so on. The difference due to the error due to other than that and the difference due to the error due to multipath are included.
The base station 40 can transmit the code phase CPb calculated by the base station 40 to the terminal 20 when determining whether or not the difference CPdif is greater than or equal to the threshold value β.
As described above, since the base station 40 can recognize whether or not the terminal 20 is in a position close to the base station 40, the condition that the terminal 20 is in a position very close to the base station 40 is satisfied. When it is determined that the difference CPdif is equal to or greater than the threshold value β, the base station code phase CPb1 and the like can be transmitted to the terminal 20. If the condition that the terminal 20 is located very close to the base station 40 is satisfied, the terminal code phase CPm should be almost the same as the base station code phase CPb if the terminal code phase CPm is not affected by the multipath. For this reason, it is reasonable for the terminal 20 to use the base station code phase CPb for positioning. In addition, it is appropriate to use the base station code phase CPb calculated by the adjacent base station 40 for positioning instead of using the terminal code phase CPm calculated by the terminal 20 using a multipath signal. . That is, there is a high possibility that the positioning accuracy of the terminal 20 is improved.
As a result, the base station 40 provides the base station code phase CPb to the terminal 20 that can communicate with the base station 40 only when a condition that it is appropriate to use the base station code phase CPb is satisfied. be able to.

The above is the configuration of the positioning system 10 according to the present embodiment. Hereinafter, an example of the operation will be described mainly using FIG. 9.
FIG. 9 is a schematic flowchart showing an operation example of the positioning system 10.
First, the base station 40 calculates an RTT with the terminal 20 (step ST1 in FIG. 9). This step ST1 is an example of a propagation time calculation step.

Subsequently, the base station 40 determines whether or not the RTT is equal to or less than the time threshold value α (step ST2). This step ST2 is an example of a propagation time evaluation step.
When determining that the RTT is equal to or less than the time threshold value α, the base station 40 receives the radio wave S1 and the like (step ST3). This step ST3 is an example of a satellite signal receiving step.
Subsequently, the base station 40 calculates the code phase CPb (step ST4). This step ST4 is an example of a code phase calculation step.

Subsequently, the base station 40 receives the terminal code phase CPm from the terminal 20 (step ST5). This step ST5 is an example of a positioning side code phase reception step.
Subsequently, the base station 40 calculates the code phase difference CPdif (step ST6). This step ST6 is an example of a difference calculating step.

Subsequently, the base station 40 determines whether or not at least one code phase CPdif is greater than or equal to a threshold value β (step ST7). This step ST7 is an example of a difference evaluation step.
If the base station 40 determines that at least one code phase CPdif is greater than or equal to the threshold β, the base station 40 transmits to the terminal 20 the base station code phase CPb1 and the like for the corresponding GPS satellite 12a and the like (step ST8). This step ST8 is an example of a correction value transmission step.

Subsequently, the terminal corrects the terminal code phase CPm1 or the like of the GPS satellite 12a or the like corresponding to the base station code phase CPb1 or the like to the base station code phase CPb1 (step ST9).
Subsequently, the terminal 20 performs positioning (step ST130. In step ST10, the terminal 20 uses the base station code phase CPb for the GPS satellite that has received the base station code phase CPb, and receives the base station code phase CPb. For GPS satellites that have not been performed, positioning is performed using the terminal code phase CPm.
Subsequently, the terminal 20 outputs the positioning position P (step ST11).

Note that, when the base station 40 determines in step ST2 that the RTT is larger than the time threshold value α, the base station 40 notifies the terminal 20 that the base station code phase CPb is not transmitted.
Then, in step ST7 described above, the base station 40 notifies the terminal 20 that the base station code phase CPb is not transmitted even when there is no code phase difference CPdif equal to or greater than the threshold value β.

The base station 40 can provide the base station code phase CPb to the terminal 20 that can communicate with the base station 40 only when a condition that it is appropriate to use the base station code phase CPb is satisfied. .
The terminal 20 uses the base station code phase CPb for GPS satellites that have received the base station code phase CPb, and uses the terminal code phase CPm for GPS satellites that have not received the base station code phase CPb. , Positioning can be performed with high accuracy.

(About programs and computer-readable recording media)
In the computer, the propagation time calculation step, propagation time evaluation step, satellite signal reception step, code phase calculation step, positioning side code phase reception step, difference calculation step, difference evaluation step, and correction are performed. A communication base station control program for executing a value device step or the like can be provided.
Also, a computer-readable recording medium in which such a communication base station control program is recorded can be used.

  A program storage medium used for installing the communication base station control program and the like in a computer and making it executable by the computer is, for example, a floppy disk such as a floppy (registered trademark), a CD-ROM (Compact Disc Read). Semiconductors in which programs are stored temporarily or permanently, as well as package media such as Only Memory (CD), Compact Disc-Recordable (CD-R), Compact Disc-Rewriteable (CD-RW), DVD (Digital Versatile Disc), etc. It can be realized by a memory, a magnetic disk, a magneto-optical disk, or the like.

The present invention is not limited to the above-described embodiment.
Unlike the present embodiment, the control unit 200 of the base station 40 transmits the RTT information 254 (see FIG. 7) and the code phase information 256 to the terminal 20 so that the terminal 20 calculates the code phase difference CPdif. Also good.

It is the schematic which shows the positioning system of embodiment of this invention. It is a conceptual diagram which shows the positioning method. It is the schematic which shows the main hardware constitutions of a terminal. It is the schematic which shows the main hardware constitutions of a base station. It is the schematic which shows the main software structures of a terminal It is explanatory drawing of a positioning program. It is the schematic which shows the main software structures of a base station. It is explanatory drawing of a code phase difference calculation program. It is a schematic flowchart which shows the operation example of a positioning system.

Explanation of symbols

  12a, 12b, 12c, 12d, 12e, 12f ... GPS satellite, 20A, 20B ... terminal, 40 ... base station, 212 ... RTT calculation program, 214 ... RTT evaluation program, 216. ..Satellite signal reception program, 218... Code phase calculation program, 220... Terminal code phase reception program, 222... Code phase difference calculation program, 224. Correction value transmission program

Claims (7)

A communication base station that can communicate with a positioning device that uses satellite signals from a plurality of positioning satellites and is located at a fixed position,
A propagation time calculating means for calculating a propagation time for communication radio waves to propagate between the positioning devices;
A propagation time evaluation means for determining whether or not the propagation time is within a predetermined time tolerance range;
Satellite signal receiving means for receiving the satellite signal;
Code phase calculating means for calculating the code phase of each satellite signal;
Positioning side code phase receiving means for receiving a positioning side code phase that is a code phase of each satellite signal calculated by the positioning device;
A difference calculating means for calculating a difference between the code phase calculated by the communication base station and a positioning side code phase;
A difference evaluation means for determining whether or not the difference is within a multipath influence range, which is a difference range when affected by a multipath;
A correction value transmitting means for transmitting the code phase calculated by the communication base station to the positioning device when the difference evaluating means determines that the difference is within the multipath affected range;
A communication base station characterized by comprising:   The time allowable range is defined as a time range in a case where the communication base station and the positioning device are close enough to be considered to be substantially the same. The communication base station according to 1.   The communication base station according to claim 1 or 2, wherein the multipath influence range is defined in consideration of a distance corresponding to the time allowable range and a calculation error of the positioning side code phase. . A communication base station that is communicable with a positioning device that uses satellite signals from a plurality of positioning satellites and that is positioned at a fixed position calculates a propagation time during which a communication radio wave propagates between the positioning devices. A propagation time calculation step;
A propagation time evaluation step in which the communication base station determines whether or not the propagation time is within a predetermined time allowable range;
A satellite signal receiving step in which the communication base station receives the satellite signal;
A code phase calculating step in which the communication base station calculates a code phase of each of the satellite signals;
A positioning side code phase receiving step in which the communication base station receives a positioning side code phase that is a code phase of each satellite signal calculated by the positioning device;
A difference calculating step in which the communication base station calculates a difference between the code phase calculated by the communication base station and a positioning side code phase;
The communication base station, a difference evaluation step for determining whether the difference is within a multipath influence range that is a difference range when the difference is affected by a multipath; and
Correction value transmission step of transmitting the code phase calculated by the communication base station to the positioning device when the communication base station determines that the difference is within the multipath influence range in the difference evaluation step. When,
A method for controlling a communication base station, comprising: On the computer,
A communication base station that is communicable with a positioning device that uses satellite signals from a plurality of positioning satellites and that is positioned at a fixed position calculates a propagation time during which a communication radio wave propagates between the positioning devices. A propagation time calculation step;
A propagation time evaluation step in which the communication base station determines whether or not the propagation time is within a predetermined time allowable range;
A satellite signal receiving step in which the communication base station receives the satellite signal;
A code phase calculating step in which the communication base station calculates a code phase of each of the satellite signals;
A positioning side code phase receiving step in which the communication base station receives a positioning side code phase that is a code phase of each satellite signal calculated by the positioning device;
A difference calculating step in which the communication base station calculates a difference between the code phase calculated by the communication base station and a positioning side code phase;
The communication base station, a difference evaluation step for determining whether the difference is within a multipath influence range that is a difference range when the difference is affected by a multipath; and
Correction value transmission step of transmitting the code phase calculated by the communication base station to the positioning device when the communication base station determines that the difference is within the multipath influence range in the difference evaluation step. When,
A communication base station control program comprising: On the computer,
A communication base station that is communicable with a positioning device that uses satellite signals from a plurality of positioning satellites and that is positioned at a fixed position calculates a propagation time during which a communication radio wave propagates between the positioning devices. A propagation time calculation step;
A propagation time evaluation step in which the communication base station determines whether or not the propagation time is within a predetermined time allowable range;
A satellite signal receiving step in which the communication base station receives the satellite signal;
A code phase calculating step in which the communication base station calculates a code phase of each of the satellite signals;
A positioning side code phase receiving step in which the communication base station receives a positioning side code phase that is a code phase of each satellite signal calculated by the positioning device;
A difference calculating step in which the communication base station calculates a difference between the code phase calculated by the communication base station and a positioning side code phase;
The communication base station, a difference evaluation step for determining whether the difference is within a multipath influence range that is a difference range when the difference is affected by a multipath; and
Correction value transmission step of transmitting the code phase calculated by the communication base station to the positioning device when the communication base station determines that the difference is within the multipath influence range in the difference evaluation step. When,
A computer-readable recording medium recording a communication base station control program. A positioning device capable of communicating with a communication base station located at a fixed position and positioning using satellite signals from a plurality of positioning satellites,
It is determined by the communication base station that a propagation time for communication radio waves to propagate between the positioning devices is within a predetermined time tolerance, and the communication base station receives the satellite signal. The difference between the calculated code phase and the positioning-side code phase that is the code phase of each satellite signal calculated by the positioning device is calculated, and the difference range when the difference is affected by multipath When the code base calculated by the communication base station is received, the positioning is performed using the code phase and the positioning side code phase calculated by the communication base station. A positioning device characterized by that.

Images