JP2003344522A - Positioning system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positioning system that is shortened in positioning time, improved in positioning probability or positioning accuracy, and reduced in communication charge. <P>SOLUTION: A first GPS receiver 10 which becomes a mobile station is provided with a communication section 14 which receives satellite information transmitted from a second GPS receiver 20 which becomes a base station, a satellite information storing section 13 which stores the received satellite information, and a position calculating section 12 which calculates the present position based on signals received from GPS satellites 31-33 by means of a GPS satellite signal receiving section 11 and the satellite information stored in the storing section 13. The receiver 10 is shortened in positioning time and improved in positioning probability or positioning accuracy by acquiring the satellite information by communicating with the base station. A communication start discriminating section 15 reduces the number of communicating times by discriminating the necessity of starting communication with the base station based on at least any one of the stored state of the satellite information, the catching states of the GPS satellites 31-33, and time information or the history information of positioned results. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a GPS (Global P
ositioning System).

[0002]

2. Description of the Related Art In recent years, a GPS receiver serving as a base station and a GPS receiver serving as a mobile station have been used.
There is provided a network-assisted GPS positioning system that transmits satellite information collected in advance by an S receiver to a GPS receiver on a mobile station side via a communication line.

By the way, in a GPS receiver, the reception timing is synchronized with the transmission timing of the pseudo noise code transmitted from the GPS satellite at the time of position measurement, so that the timing deviation can be determined, and the GPS satellite can be obtained based on this deviation amount. Time from GPS to GPS receiver, ie GPS satellite and G
We are seeking the distance to the PS receiver. In addition, the GPS receiver receives the navigation message transmitted from the GPS satellites to obtain the position of each satellite. By obtaining the distance from at least three GPS satellites and the position of the GPS satellites, the current position can be obtained. Can be positioned.

Here, the navigation message includes the source G
Ephemeris, which is the orbit information and correction information of PS satellites, and satellite information, called almanac, which is the orbit information of all GPS satellites, are included. If such satellite information is acquired in advance, position measurement can be performed. Since the approximate position of the GPS satellite is sometimes known, the time taken to synchronize with the pseudo noise code sent from the GPS satellite can be shortened, the positioning probability can be improved, and the current position can be measured in a short time.

However, the effective period of the ephemeris is about 2 hours, and the ephemeris is updated to the latest value after the effective period elapses. Therefore, the GPS receiver needs to acquire the latest ephemeris every about 2 hours. About 30
Since it takes seconds, there is a problem that the positioning time becomes very long when updating the ephemeris, and there is a problem that the positioning cannot be performed because the decoding cannot be performed.

Therefore, in the network-assisted GPS, the GPS receiver on the mobile station side communicates with the GPS receiver on the base station side to obtain satellite information such as ephemeris obtained on the base station side. Therefore, by using the satellite information obtained on the base station side, it is possible to eliminate the process of acquiring the ephemeris on the mobile station side, thereby shortening the positioning time and improving the positioning accuracy.

[0007]

However, in the position measurement system of the network assist type GPS system,
Communication is performed between the base station and the mobile station in order to receive the satellite information obtained on the base station side, and there is a problem that the communication fee is high.

The present invention has been made in view of the above problems. An object of the present invention is to shorten the positioning time, improve the positioning probability, improve the positioning accuracy, and reduce the communication charge. To provide a measurement system.

[0009]

In order to achieve the above object, according to the invention of claim 1, a first satellite signal receiving section for receiving a satellite signal transmitted from a GPS satellite, satellite information transmitted from the outside. A first communication unit that receives the satellite information, a first satellite information storage unit that stores the satellite information received by the first communication unit,
A first GPS receiver including a position calculation unit that calculates a current position based on the satellite signal received by the first satellite signal reception unit and the satellite information stored in the first satellite information storage unit;
A second satellite signal receiving section for receiving satellite signals transmitted from GPS satellites, a second satellite information storage section for storing satellite information obtained from satellite signals received by the second satellite signal receiving section,
And a second communication unit for communicating with the first communication unit and transmitting the satellite information stored in the second satellite information storage unit to the first communication unit. And the first GPS receiver based on at least one of information indicating a storage status of satellite information related to GPS satellites, information indicating a capture status, time information, or history information of positioning results. A communication start determination unit that determines whether to start communication between the first and second communication units, and only when the communication start determination unit determines to start communication, the first communication Section communicates with the second communication section, and the second GP
A position measurement system characterized by acquiring satellite information stored in a second satellite information storage unit from an S receiver.

According to a second aspect of the invention, in the first aspect of the invention, the number of effective ephemeris stored in the satellite information storage unit is used as the information representing the storage state of the satellite information, and the communication start determination unit is If the number of effective ephemeris is less than the reference value, the communication between the first and second communication units is started.

According to a third aspect of the present invention, in the first aspect of the invention, the number of effective ephemeris stored in the satellite information storage unit and the number of GPS satellites existing in the sky are used as the information representing the storage state of the satellite information. If the ratio of the number of effective ephemeris to the number of GPS satellites existing in the sky is lower than the reference value, the communication start determination unit starts the communication between the first and second communication units. It is characterized by

According to a fourth aspect of the present invention, in the first aspect of the invention, the number of effective ephemeris stored in the satellite information storage unit is G, which is information indicating the storage state of the satellite information.
A value weighted by the elevation angle of the PS satellite is used, and if the value of the number of valid ephemeris weighted by the elevation angle of the GPS satellite is smaller than the reference value, the communication start determination unit determines between the first and second communication units. The communication is started.

According to a fifth aspect of the present invention, in the first aspect of the invention, the DOP value of the GPS satellite in which the effective ephemeris is stored in the satellite information storage unit is used as the information indicating the storage state of the satellite information, and the communication is performed. The start determination unit is characterized by starting communication between the first and second communication units when the DOP value is larger than the reference value.

According to a sixth aspect of the invention, in the first aspect of the invention, the information indicating the acquisition status of the GPS satellites is GPS.
If the value obtained by weighting the number of captured satellites by the elevation angle is smaller than the reference value, the communication start determination unit uses the value obtained by weighting the number of captured satellites by the elevation angle. It is characterized in that communication between them is started.

According to a seventh aspect of the present invention, in the first aspect of the invention, the DOP value of the captured GPS satellite is used as the information indicating the capture state of the GPS satellite, and the communication start determining unit determines that the DOP value is greater than the reference value. If too large, first and second
The communication between the communication units is started.

According to the invention of claim 8, in the invention of claim 1, the elevation angle of the GPS satellite first captured at the start of positioning is used as the information representing the capture status of the GPS satellite, and the communication start determining unit first If the elevation angle of the captured GPS satellite is higher than the reference angle, communication between the first and second communication units is started.

According to a ninth aspect of the present invention, in the first aspect of the present invention, the time elapsed is used as the time information since the previous positioning, and the communication start determination unit determines whether the first and It is characterized in that communication between the second communication units is started.

According to a tenth aspect of the present invention, in the first aspect of the present invention, the remaining time of the effective time of the ephemeris is used as the time information, and the communication start determining unit determines whether the remaining time is shorter than the reference time. It is characterized in that communication between the second communication units is started.

According to the invention of claim 11, in the invention of claim 1, the remaining time of the effective time of the ephemeris is used as the time information, and the signal from the GPS satellite acquired is used as the information indicating the acquisition status of the GPS satellite. When the remaining time is shorter than the reference time and the C / N ratio is equal to or less than the reference value, the first communication start determination unit uses the C / N ratio and
And the communication between the second communication unit is started.

According to a twelfth aspect of the present invention, in the first aspect of the present invention, the previous positioning result is used as the history information of the positioning result, and the communication start determining unit determines whether the first positioning result is the first positioning result.
And the communication between the second communication unit is started.

In the thirteenth invention, the first to twelfth inventions are provided.
In any one of the inventions, the previous positioning result is used as the history information of the positioning result, and the communication start determining unit determines whether or not the communication is necessary so that the possibility of communication is high when the previous positioning has not been performed. It is characterized in that the judgment condition for judgment is changed.

In the fourteenth aspect of the present invention, the first to twelfth aspects are provided.
In any one of the inventions, the number of GPS satellites captured in the previous positioning is used as the history information of the positioning result, and the communication start determination unit has the number of GPS satellites captured in the previous positioning less than a predetermined number of satellites. In this case, the determination condition for determining the necessity of communication is changed so that the possibility of communication is increased.

According to the fifteenth aspect of the present invention, the first to twelfth aspects are provided.
In any one of the inventions, the error rate at the time of decoding the navigation message from the GPS satellite captured at the time of the previous positioning is used as the history information of the positioning result, and the communication start determination unit has the error rate higher than the reference value. When it is high, it is characterized in that the judgment condition for judging the necessity of communication is changed so as to increase the possibility of communication.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) FIG. 1 is a block diagram of this embodiment. In this embodiment, a first GPS receiver 10 serving as a mobile station and a second GPS receiver serving as a base station. The receiver 20 constitutes a position measurement system. In the following, a case where three GPS satellites 31 to 33 can be captured will be described as an example. However, since the same is true when the number of GPS satellites that can be captured is four or more, description thereof will be omitted.

The second GPS receiver 20 on the base station side is
GP that receives signals transmitted from PS satellites 31 to 33
S satellite signal receiver 21 (second satellite signal receiver) and G
A satellite information storage unit 2 that stores a navigation message obtained by down-converting the signal received by the PS satellite signal receiving unit 21 and further decoding it as satellite information.
2 (second satellite information storage unit) and the communication unit 2 that performs wireless communication by radio signal between the GPS receiver 10 on the mobile station side
3 (second communication unit). In the second GPS receiver 20, the GPS satellite signal receiving unit 21
The satellite information storage unit 22 receives navigation signals obtained by receiving signals from the satellites 31 to 33, down-converting the received signals, and further decoding them.
However, the satellite information may be updated periodically.

On the other hand, the first GPS receiver 10 on the mobile station side
Is a GPS satellite signal receiver 11 (first satellite signal receiver) that receives signals transmitted from GPS satellites 31 to 33.
And a second GPS receiver 20 on the side of the base station to perform wireless communication by radio signals, and to communicate with a communication unit 14 (first communication unit) that receives satellite information transmitted from the side of the base station. The satellite information storage unit 13 that stores the satellite information received by the unit 14
(First satellite information storage unit) and GPS satellite signal receiving unit 1
The position calculation unit 12 that calculates the current position based on the signal received by 1 and the satellite information stored in the satellite information storage unit 13.
And a satellite capture check unit 1 for confirming the capture state of the GPS satellite based on the signal received by the GPS satellite signal receiving unit 11.
6, a timekeeping unit 17 for obtaining the current time, a positioning history storage unit 18 for storing history information of positioning results, and a communication start determination unit 1 for determining whether or not to start communication by the communication unit 14.
5 and.

Here, in the communication start judging section 15, the information indicating the storage status of the satellite information of the GPS satellites 31 to 33 from the satellite information storage section 13 is sent from the satellite acquisition check section 16 to the GP.
It is possible to obtain and use the information indicating the capture state of the S satellite, the time information from the clock unit 17, and the history information of the positioning result from the positioning history storage unit 18, respectively, and use at least one of these information. Based on the determination, whether or not to start communication by the communication unit 14 is determined.

Then, the communication start judgment unit 15 is connected to the communication unit 1
If the communication unit 14 determines to start the communication according to No. 4, the communication unit 14 communicates with the communication unit 23 of the GPS receiver 20, and the satellite stored in the satellite information storage unit 22 from the GPS receiver 20. Information is transmitted and the received satellite information is stored in the satellite information storage unit 13. In this way, the communication start determining unit 15 determines whether or not the latest satellite information needs to be acquired from the above information, and the communication unit 14 performs communication only when the latest satellite information needs to be acquired. Since the communication is started, the number of communications between the communication unit 14 and the communication unit 23 can be reduced to reduce the communication charge, and when the latest satellite information is required, the second GPS on the base station side can be used.
Since the satellite information is acquired from the receiver 20, the positioning time can be shortened, the positioning probability can be improved, and the positioning accuracy can be improved.

In this embodiment, the communication unit 14 and the communication unit 2
Although wireless communication using radio signals is being performed with
The communication method between the communication unit 14 and the communication unit 23 is not limited to wireless communication using a radio signal, and wireless communication using an optical signal such as infrared light may be used, or wired communication may be used. Alternatively, a communication system in which the human body is part of the transmission path may be used.

(Embodiment 2) FIG. 2 shows Embodiment 2 of the present invention.
It will be described based on. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In the present embodiment, the communication start determination unit 15 determines whether to start communication based on the number of ephemeris stored in the satellite information storage unit 13.

FIG. 2 is a flow chart for explaining the judging operation by the communication start judging section 15.
Of the ephemeris stored in the satellite information storage unit 13 obtains the number of ephemeris that has not expired (referred to as the effective ephemeris number) (S1), and compares the effective ephemeris number with a predetermined reference value n. (S2), if the number of effective ephemeris is the reference value n or more, communication is not performed, and if it is less than the reference value n, communication is started (S2).
3).

Here, the reference value n of the number of effective ephemeris may be set to such a number that the positioning calculation can be performed by quickly capturing some of the n GPS satellites. If n or more valid ephemeris are stored in 13, it can be determined that the information that can be positioned is sufficiently held, and the communication fee can be reduced by refraining from communication with the base station. In the first embodiment, the case where three GPS satellites 31 are captured has been described as an example. However, the reference value n of effective ephemeris may be set to, for example, four or five or more. You may set it.

(Embodiment 3) FIG. 3 shows Embodiment 3 of the present invention.
It will be described based on. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In the present embodiment, the communication start determination unit 15 estimates the number of GPS satellites existing in the sky from the satellite information such as almanac stored in the satellite information storage unit 13 and stores the number in the satellite information storage unit 13. Whether or not to start communication is determined based on the number of existing ephemeris and the number of GPS satellites existing in the sky.

FIG. 3 is a flow chart for explaining the judging operation by the communication start judging section 15, and the communication start judging section 15 is shown.
Of the ephemeris stored in the satellite information storage unit 13 obtains the number of valid ephemeris (the number of valid ephemeris) that has not expired (S4).
The ratio of the number of effective ephemeris to the number of satellites is compared with a predetermined reference value r% (S5). If the ratio is r% or more, communication is not performed, and if it is less than r%, communication is started. (S6).

That is, when effective ephemeris is acquired for GPS satellites of r% or more among the GPS satellites existing in the sky, it can be determined that sufficient information for positioning is held, By refraining from communication with the base station, communication charges can be reduced. The reference value r% of the above ratio may be a fixed value such as 70%, 80% or 90%, or may be changed depending on the number of satellites existing in the sky.

(Embodiment 4) FIG. 4 shows Embodiment 4 of the present invention.
It will be described based on. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In this embodiment, the communication start determination unit 15 determines the elevation angle of the GPS satellite corresponding to the number of ephemeris of which the expiration date has not passed among the ephemeris of each GPS satellite stored in the satellite information storage unit 13. According to the weighted value, it is determined whether or not communication is started.

FIG. 4 is a flow chart for explaining the judging operation by the communication start judging section 15.
Resets the value of the variable SUM (S7), determines whether the ephemeris of the GPS satellites stored in the satellite information storage unit 13 is valid (S8), and if valid, the variable SU
The elevation angle of this GPS satellite is added to the value of M (S9). Then, it is determined whether or not the processing has been performed for all the GPS satellites for which the ephemeris is stored in the satellite information storage unit 13 (S10). If the processing has not been completed for all the GPS satellites, the processing returns to S8 and the above-mentioned operation is performed. The process is executed, and if the process is completed, the value of the variable SUM is compared with the predetermined reference value n (S11). If the value of the variable SUM is equal to or greater than the reference value n, communication is not performed, and if the value is less than the reference value n, communication is started (S12).

As described above, the number of effective ephemeris is weighted by the elevation angle of the GPS satellite, and if the weighted value is the reference value n or more, communication with the base station is refrained from. , Among the GPS satellites existing in the sky, if the effective ephemeris is held for the GPS satellite with a higher elevation angle, it can be determined that the information useful for position measurement is held. By refraining from communication, it is possible to reduce communication charges.

(Embodiment 5) FIG. 5 shows Embodiment 5 of the present invention.
It will be described based on. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In the present embodiment, the communication start judgment unit 15 obtains the DOP value (Dilution Of Precision) of the GPS satellites of the ephemeris that have not expired among the ephemeris stored in the satellite information storage unit 13. Based on this DOP value, it is determined whether to start communication.

FIG. 5 is a flow chart for explaining the judging operation by the communication start judging section 15.
Determines whether or not the ephemeris of the GPS satellite stored in the satellite information storage unit 13 is valid (S13), and if valid, marks the corresponding GPS satellite (S14). All GPs with Ephemeris remembered
It is determined whether the processing has been performed for the S satellite (S1
5) If the processing is not completed for all GPS satellites, the process returns to S13 to execute the above-described processing. If the processing is completed, the DO is started from the position of the marked GPS satellite.
The P value is calculated (S16). Then, the communication start determination unit 1
5 compares the DOP value with a predetermined reference value d (S1
7), if the DOP value is equal to or less than the reference value d, communication is not performed,
If it is larger than the reference value d, communication is started (S18).

As described above, GPS with effective ephemeris
If the DOP value obtained for the satellite is less than or equal to the reference value d, that is, if the GPS satellites are arranged well, it can be determined that the information useful for position measurement is held, and therefore communication with the base station is performed. By refraining from this, communication charges can be reduced.

(Embodiment 6) FIG. 6 shows Embodiment 6 of the present invention.
It will be described based on. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In this embodiment, the communication start judgment unit 15 uses the GPS satellite acquisition information detected by the satellite acquisition check unit 16, and determines whether or not to start communication based on the number of GPS satellites acquired. I'm making a decision.

FIG. 6 is a flow chart for explaining the judgment operation by the communication start judgment unit 15, after the satellite acquisition check unit 16 checks the acquisition status of GPS satellites (S
19), the communication start determination unit 15 causes the satellite capture check unit 1 to
The number of GPS satellites captured from the output of 6 is compared with the predetermined number n of satellites (S20). If the number of GPS satellites captured is equal to or larger than the predetermined number n of satellites, the number of GPS satellites between If communication is not performed and the number of satellites is less than the predetermined number n, communication is started (S21). That is, the captured G
If the number of PS satellites is greater than or equal to the predetermined number n of satellites, it is determined that the GPS satellites are in a good capture state and positioning is possible without acquiring satellite information from the base station, By refraining from communication, it is possible to reduce communication charges.

(Embodiment 7) FIG. 7 shows Embodiment 7 of the present invention.
It will be described based on. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In the present embodiment, the communication start determination unit 15 uses the GPS satellite capture information detected by the satellite capture check unit 16, and the C / N of the signals from the GPS satellites among the captured GPS satellites is used. G whose ratio is greater than or equal to a predetermined reference value c
Whether or not to start communication is determined based on the number of PS satellites.

FIG. 7 is a flow chart for explaining the judging operation by the communication start judging section 15.
First resets the value of the variable SUM (S22), determines from the output of the satellite capture check unit 16 whether a certain GPS satellite is captured (S23), and if that GPS satellite is captured, The height of the C / N ratio of the signal from the GPS satellite is compared with a predetermined reference value c (S24), and if the C / N ratio is the reference value c or more, 1 is added to the value of the variable SUM ( S25). Then, the communication start determination unit 15 determines whether the processing has been completed for all GPS satellites (S
26), if the process is not completed, return to S23 and repeat the above process. If the process is completed, the variable SU
The magnitude of the value of M and the predetermined reference value n are compared (S2
7). Here, the communication start determination unit 15 does not perform communication if the value of the variable SUM is equal to or greater than the predetermined reference value n, and the reference value n
If less than, communication is started (S2
8). That is, in the communication start determination unit 15, when n or more GPS satellites having a high C / N ratio are captured, the signal from the GPS satellites can be decoded without acquiring satellite information from the base station. By determining that the direct navigation message can be obtained and refraining from communication with the base station,
Communication charges have been reduced.

(Embodiment 8) FIG. 8 shows Embodiment 8 of the present invention.
It will be described based on. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In the present embodiment, the communication start judgment unit 15 uses the GPS satellite capture information detected by the satellite capture check unit 16, and determines the number of GPS satellites captured and the GPS.
By using the C / N ratio of the signal from the satellite and making a plurality of determinations (for example, twice in this embodiment),
It is determined whether or not to start communication.

FIG. 8 is a flow chart for explaining the judging operation by the communication start judging section 15.
First, the value of the variable SUM is reset (S29), it is determined from the output of the satellite capture check unit 16 whether a certain GPS satellite is captured (S30), and if the GPS satellite is captured, The C / N ratio of the signal from the GPS satellite is compared with the predetermined reference value c (S31), and if the C / N ratio is greater than or equal to the reference value c, 1 is added to the value of the variable SUM ( S32). Then, the communication start determination unit 15 determines whether the processing has been completed for all GPS satellites (S
33) If the process is not completed, the process returns to S30 and the above process is repeated. If the process is completed, the variable SU
The magnitude of the value of M is compared with the predetermined reference value n1 (S3).
4). Here, if the value of the variable SUM is less than the reference value n1, the communication start determination unit 15 starts communication (S35),
If it is the reference value n1 or more, the above determination is repeated again. That is, the communication start determination unit 15 resets the value of the variable SUM (S36), and determines from the output of the satellite capture check unit 16 whether or not a certain GPS satellite is captured (S3).
7) If the GPS satellite is captured, the C / N ratio of the signal from the GPS satellite is compared with the predetermined reference value c (S38), and the C / N ratio is equal to or greater than the reference value c. If there is, 1 is added to the value of the variable SUM (S39). Then, the communication start determination unit 15 determines whether or not the processing has been completed for all GPS satellites (S40). If the processing has not been completed, the processing returns to S37 and the above-described processing is repeated to complete the processing. If so, the magnitude of the value of the variable SUM and the predetermined reference value n2 are compared (S41). Here, if the value of the variable SUM is less than the reference value n2, the communication start determination unit 15 starts communication (S42), and if the value of the variable SUM is greater than or equal to the reference value n2, communication is not performed and the determination process ends.

As described above, in the present embodiment, the communication start determination unit 15 performs the determination process twice, and in the first determination, the C / N ratio of the signals among the GPS satellites captured is the reference value. When the number of GPS satellites of c or more is n1 or more, communication with the base station is refrained from. In addition, in the second determination, of the GPS satellites captured,
When the number of GPS satellites whose signal C / N ratio is the reference value c or more is n2 or more, communication with the base station is refrained from.

For example, the communication start judgment unit 15 makes the first judgment 1 second after the start of positioning, and makes the second judgment 3 seconds after that, so that the GPS that has been captured in the first judgment. Of the satellites, it is determined whether or not at least one GPS satellite with a C / N ratio of 17 or more has been captured (first acquisition).
It may be possible to determine whether or not three or more GPS satellites having an N ratio of 17 or more can be captured. If the GPS satellites can be captured under the above conditions at the time of starting positioning, the satellite information is acquired from the base station. Even if it is not acquired, it is determined that the direct navigation message can be acquired by decoding the signal from the GPS satellite, and the communication fee is reduced by refraining from communication with the base station. The number of times the communication start determination unit 15 performs the determination process and the timing of the determination process are not limited to those in the above embodiment, and can be appropriately changed according to the usage situation.

(Ninth Embodiment) FIG. 9 shows a ninth embodiment of the present invention.
It will be described based on. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In the present embodiment, the communication start determination unit 15 uses the GPS satellite acquisition information detected by the satellite acquisition check unit 16 to weight the number of captured GPS satellites with the elevation angle of each GPS satellite. Based on that, it is determined whether or not to start communication.

FIG. 9 is a flow chart for explaining the judging operation by the communication start judging section 15.
First resets the value of the variable SUM (S43), determines from the output of the satellite acquisition check unit 16 whether a certain GPS satellite is acquired (S44), and if that GPS satellite is acquired, The elevation angle is added to the value of the variable SUM (S45). Then, the communication start determination unit 15 determines that all G
It is determined whether or not the processing has been completed for the PS satellite (S4
6) If the process is not completed, the process returns to S44 and repeats the above process. If the process is completed, the variable SUM
Is compared with the predetermined reference value (S47). Here, the communication start determination unit 15 does not perform communication if the value of the variable SUM is equal to or greater than the predetermined reference value n, and starts communication if the value is less than the reference value n (S48). That is, when more GPS satellites with a high elevation angle are captured, it is possible to determine that an error is unlikely to occur when the navigation message is decoded and the capture situation is more advantageous, so refrain from communication with the base station. By doing so, communication charges can be reduced.

In this embodiment, the communication start judging section 15
Determines the necessity of communication based on the value obtained by weighting the number of captured GPS satellites according to the elevation angle.
The necessity of communication may be determined in consideration of the information on the C / N ratio of the signal from the S satellite. For example, the number of GPS satellites not only being captured but also having a C / N ratio of a signal from the GPS satellites equal to or greater than a predetermined reference value is obtained by weighting the number of elevation angles, and the communication requirement is calculated from this value. Whether or not communication may be performed may be determined based on a value obtained by weighting the number of captured GPS satellites with a value obtained by multiplying the elevation angle by the C / N ratio. ,
The determination process may be performed multiple times.

(Embodiment 10) Embodiment 10 of the present invention will be described with reference to FIG. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In the present embodiment, the communication start judging unit 15 uses the acquisition information of the GPS satellites detected by the satellite acquisition checking unit 16 to find the DOP value for the acquired GPS satellites, and communicates based on this DOP value. To determine whether to start.

FIG. 10 is a flow chart for explaining the judging operation by the communication start judging section 15.
5 determines from the output of the satellite capture check unit 16 whether or not a certain GPS satellite is captured (S49), and if so, marks the GPS satellite (S50), It is determined whether or not the capture status determination process has been performed for (S51), and if the capture status determination process is not completed, the process returns to S49 to execute the above process, and if the process is completed, mark A DOP value is calculated from the position of the GPS satellite marked with (S52). Then, the communication start determination unit 15 compares the DOP value with the predetermined reference value d (S
53), if the DOP value is less than or equal to the reference value d, communication is not performed, and if it is greater than the reference value d, communication is started (S54).

As described above, when the DOP value obtained for the captured GPS satellite is less than or equal to the reference value d, that is, when the arrangement of the GPS satellites is good, information that is advantageous for position measurement is held. Therefore, the communication fee can be reduced by refraining from communication with the base station.

In this embodiment, the communication start judging section 15
Finds the DOP value for the GPS satellites it is capturing,
The necessity of communication is judged based on this DOP value.
Information on the C / N ratio of the signal from the PS satellite may be added to the DOP value to determine the necessity of communication. For example, the DOP value is obtained only for the GPS satellites whose C / N ratio of the signal from the GPS satellites is not less than the predetermined reference value, and the necessity of communication is determined from this DOP value. Alternatively, the determination process may be performed multiple times.

(Eleventh Embodiment) An eleventh embodiment of the present invention will be described with reference to FIG. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In this embodiment, whether the communication start judging section 15 uses the GPS satellite acquisition information detected by the satellite acquisition check section 16 to start communication based on the elevation angle of the GPS satellite first acquired at the start of positioning. It is judged whether or not.

FIG. 11 is a flow chart for explaining the judgment operation by the communication start judging section 15. After the satellite acquisition checking section 16 checks the acquisition status of GPS satellites (S55), the communication start judging section 15 detects the satellite acquisition. The elevation of the GPS satellite first captured at the start of positioning from the output of the check unit 16 is compared with the height of a predetermined reference angle n (S5
6) If the elevation angle of the first captured GPS satellite is equal to or less than the reference angle n, communication is not performed, and if it is higher than the reference angle n, communication is started (S57).

As described above, when the elevation angle of the GPS satellite first captured is equal to or less than the reference angle n (for example, about 30 degrees),
Since the communication with the base station is refrained from, and the GPS satellite whose elevation angle is equal to or smaller than the reference angle n can be captured first, it is easy to capture the GPS satellite whose elevation angle is higher than the reference angle n. Since it can be determined that it is a more advantageous acquisition situation, the communication fee can be reduced by refraining from communication with the base station. On the other hand, the first captured G
When the elevation angle of the PS satellite is higher than the reference angle n, the communication with the base station is started to acquire the latest satellite information so that positioning can be performed.

(Embodiment 12) Embodiment 12 of the present invention will be described with reference to FIG. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In the present embodiment, the communication start determination unit 15 uses the time information detected by the clock unit 17 to determine whether to start communication based on the elapsed time from the previous positioning.

FIG. 12 is a flow chart for explaining the judgment operation by the communication start judging unit 15, after the time measuring unit 17 checks the elapsed time from the last positioning (S5).
8), the communication start determination unit 15 compares the elapsed time from the previous positioning detected by the time counting unit 17 with a predetermined reference time t (S59), and if the elapsed time is less than or equal to the reference time t, performs communication. If it is longer than the reference time t, communication is started (S60).

As described above, if the elapsed time from the previous positioning is equal to or less than the reference time t, it is considered that the acquisition status of GPS satellites is the same as the previous time, and the satellite information is not acquired from the base station. Directly decodes signals from GPS satellites,
Since it can be determined that the navigation message can be acquired, the communication fee can be reduced by refraining from communication with the base station. Further, when the time exceeding the reference time t has elapsed since the last positioning, sufficient satellite information can be obtained by communicating with the base station, so that the positioning time can be shortened, Positioning accuracy can be improved.

(Embodiment 13) Embodiment 13 of the present invention will be described with reference to FIG. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In the present embodiment, the communication start determination unit 15 uses the time information detected by the time counting unit 17, and the current time and the remaining effective time of the ephemeris of each GPS satellite (hereinafter referred to as the remaining effective time). Based on and, it is determined whether or not to start communication.

FIG. 13 is a flow chart for explaining the judging operation by the communication start judging section 15.
5 first sets the value of the variable MIN to the maximum value of the effective time of the ephemeris (S61), then determines whether the ephemeris of a certain GPS satellite is effective (S62), and if the ephemeris is effective, Remaining effective time is variable MIN
If it is shorter than the value of, the remaining valid time is set in the variable MIN (S63). Then, the communication start determination unit 15
Determines whether the processing has been completed for all GPS satellites (S64), and if the processing has not been completed, S62
Then, the processing described above is repeated, and if the processing is completed, the length of the value of the variable MIN and the predetermined reference time t are compared (S65). Here, the communication start determination unit 15 does not perform communication if the value of the variable MIN is the reference time t or more, and starts communication with the base station if the value is shorter than the reference time t.

As described above, in the present embodiment, the communication start determination unit 15 determines the necessity of communication based on the remaining effective time of the ephemeris of each GPS satellite, and the remaining effective time of the ephemeris of all the GPS satellites. If the time is equal to or longer than the reference time t, it can be determined that the position measurement can be performed without acquiring the satellite information from the base station. Therefore, the communication fee can be reduced by refraining from communication with the base station.

In the present embodiment, the communication start determination unit 15 determines whether or not communication is required based on the remaining effective time of the ephemeris. However, the number of GPS satellites for which the ephemeris is effective is counted and the ephemeris is effective. The necessity of communication may be determined in consideration of the number of GPS satellites. For example, if the number of GPS satellites for which the ephemeris is valid is 3 or more and the remaining valid time of the ephemeris is 15 minutes or more, the communication with the base station may be refrained from, and the number of communications can be reduced. By doing so, communication charges can be reduced.

(Fourteenth Embodiment) A fourteenth embodiment of the present invention will be described with reference to FIG. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In the present embodiment, the communication start judgment unit 15 uses the time information detected by the clock unit 17 and the GPS satellite acquisition information detected by the satellite acquisition check unit 16 to determine the ephemeris of each GPS satellite. Based on the remaining effective time and the C / N ratio of the signal from each GPS satellite, it is determined whether or not to start communication.

FIG. 14 is a flow chart for explaining the judging operation by the communication start judging unit 15.
5 first sets the value of the variable MIN to the longest valid time of the ephemeris (S67), then determines whether the ephemeris of a certain GPS satellite is valid (S68), and if the ephemeris is valid, Remaining effective time is variable MIN
If it is shorter than the value of, the remaining valid time is set in the variable MIN (S69). Then, the communication start determination unit 15
Determines whether the processing has been completed for all GPS satellites (S70), and if the processing has not been completed, S68
Then, the above process is repeated, and if the process is completed, the length of the value of the variable MIN and the predetermined reference time t are compared (S71). Here, if the value of the variable MIN is equal to or longer than the reference time t, the communication start determination unit 15 does not perform the communication. The checking unit 16 checks the GPS satellite capture status (S72), and captures the G
Whether the C / N ratio of the signal from the PS satellite and the predetermined reference value c is high or low is determined (S73). If the C / N ratio is the reference value c or more, communication is not performed, and if it is smaller than the reference value c. Communication with the base station is started (S74).

As described above, the communication start determination unit 15 determines that the remaining effective time of the ephemeris is shorter than the reference time, and
Only when the C / N ratio of the signal from the captured GPS satellite is smaller than the reference value c, communication with the base station is performed, and even when the remaining effective time of the ephemeris is shorter than the reference time. , If the C / N ratio is greater than or equal to the reference value c,
The communication fee can be reduced by decoding the signal from the GPS satellite, determining that the ephemeris can be directly acquired, and refraining from communication with the base station. If the remaining effective time of the ephemeris is shorter than the reference time and the C / N ratio of the captured GPS satellite signal is smaller than the reference value c, the communication with the base station is started. As a result, sufficient satellite information can be obtained, so that positioning time can be shortened and positioning accuracy can be improved.

(Fifteenth Embodiment) A fifteenth embodiment of the present invention will be described with reference to FIG. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In this embodiment, as in the fourteenth embodiment,
The communication start determination unit 15 detects the time information detected by the clock unit 17 and the G detected by the satellite acquisition check unit 16.
The information acquired from the PS satellites is used to determine whether or not to start communication based on the remaining effective time of the ephemeris of each GPS satellite and the C / N ratio of the signal from each GPS satellite. . Then, in the fourteenth embodiment, when the remaining effective time of the ephemeris is equal to or longer than the reference time, communication with the base station is not performed, whereas in the present embodiment, the remaining effective time of the ephemeris is C / N of the signal from the acquired GPS satellite even if it is longer than the reference time
When the ratio is below the reference value, communication is performed.

FIG. 15 is a flow chart for explaining the judging operation by the communication start judging section 15, and since the processing of S67 to S74 is the same as the processing of S67 to S74 of FIG. 14, its explanation is omitted. As a result of the communication start determination unit 15 comparing the variable MIN and the reference time t in S71, if the variable MIN is equal to or longer than the reference time t, the communication start determination unit 1
In step 5, the satellite acquisition check unit 16 checks the acquisition status of the GPS satellites (S75), and determines whether the C / N ratio of the signals from the acquired GPS satellites and the predetermined reference value c2 are high or low (S76). , C / N ratio is greater than the reference value c2, communication is not performed, and if the C / N ratio is less than or equal to the reference value c2, communication with the base station is started (S77).

As described above, the communication start determination unit 15 determines that the remaining effective time of the ephemeris is shorter than the reference time, and
When the C / N ratio of the signal from the captured GPS satellite is smaller than the reference value c1, or the remaining effective time of the ephemeris is equal to or longer than the reference time and the GP that is capturing is
Communication with the base station is started only when the C / N ratio of the signal from the S satellite is equal to or less than the reference value c2. Thus, even if the remaining effective time of the ephemeris is shorter than the reference time, if the C / N ratio is the reference value c1 or more, it is determined that the signal from the GPS satellite can be decoded and the ephemeris can be directly obtained. By refraining from communicating with the station, communication charges can be reduced. Even when the remaining effective time of the ephemeris is equal to or longer than the reference time, the C / N ratio is equal to the reference value c.
If the number is 2 or less, it is possible to measure the position with high accuracy by determining that the GPS satellite acquisition state is bad and acquiring the ephemeris from the base station.

(Sixteenth Embodiment) The sixteenth embodiment of the present invention will be described with reference to FIG. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In the present embodiment, the communication start determination unit 15 uses the history information of the positioning result stored in the positioning history storage unit 18 and determines to start the communication if the previous positioning has not been performed.

FIG. 16 is a flow chart for explaining the judging operation by the communication start judging section 15.
5 checks the history information of the positioning result stored in the positioning history storage unit 18 (S78), determines whether or not the positioning was successful at the previous positioning (S79), and if the positioning is successful, the communication is performed. If the positioning fails without performing the step S3, the communication with the base station is started (S80).

In this way, the communication start determination unit 15 determines that the GPS satellite acquisition state is bad and performs communication with the base station when the positioning has failed at the previous positioning.
Since the satellite information is acquired from the base station, the accuracy of position measurement can be improved and the time required for position measurement can be shortened. In addition, the communication start determination unit 15 determines that the GPS satellite acquisition status is good and refrains from communicating with the base station if the positioning was successful at the time of the previous positioning, and therefore the communication charge is set. It can be reduced. Note that the communication start determination unit 15 may make another determination after making the above determination.

(Embodiment 17) Embodiment 17 of the present invention will be described with reference to FIG. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In the present embodiment, the communication start determination unit 15 uses the history information of the positioning result stored in the positioning history storage unit 18, and if the previous positioning has not been performed, the communication possibility is increased so that the possibility of communication increases. The judgment conditions for judging the necessity are changed.
Here, changing the judgment condition so as to increase the possibility of communication means, for example, changing the judgment condition so as to increase the number of times of communication in the same environment. The same environment means a state in which the same satellite information is held and the same GPS satellite is captured at the same time.

FIG. 17 is a flow chart for explaining the judging operation by the communication start judging section 15.
5 checks the history information of the positioning result stored in the positioning history storage unit 18 (S81), determines whether the positioning was successful at the previous positioning (S82), and determines if the positioning was successful. The condition is set to a normal condition, and if the positioning is unsuccessful, the judgment condition for judging the necessity of communication is changed so as to increase the possibility of starting communication (S83).

As described above, the communication start determination unit 15 changes the determination condition based on the positioning result at the time of the previous positioning, and if the previous positioning has failed, the determination condition is set to increase the possibility of communication. Is changing. Therefore, when the GPS satellite acquisition condition is poor, the chances of acquiring satellite information from the base station are increased by changing the judgment conditions so that the possibility of communication increases, so sufficient satellite information is obtained. Therefore, the positioning time can be shortened and the positioning accuracy can be improved.

For example, when the communication start judging unit 15 judges the necessity of communication by using the ratio between the number of GPS satellites existing in the sky and the number of effective ephemeris stored in the satellite information storage unit 13, Normally, the communication is started when the ratio is 80% or less, whereas the determination condition is made stricter when the previous positioning has failed, and the communication is started when the ratio is 90% or less. As a result, the possibility of communication can be increased. In addition, the communication start determination unit 15
When determining the necessity of communication using the number of captured GPS satellites, communication is normally started when the number of acquisitions is 3 or less, whereas acquisition is performed when the previous positioning has failed. The possibility of communication can be increased by starting communication when the number is four or less. Further, the communication start determination unit 15 determines that the C / N of the signal from the captured GPS satellite
When the necessity of communication is determined using the ratio, the communication is normally started when the C / N ratio is 17 or less, whereas the C / N ratio is 20 or less when the previous positioning has failed. In this case, the possibility of communication can be increased by starting the communication.

Further, the communication start judging section 15 judges the necessity of communication after performing the above-mentioned processing and determining the judgment condition. The judgment condition is the judgment condition described in the second to fifteenth embodiments. Any of the above conditions may be used, and the determination may be performed a plurality of times.

(Embodiment 18) An embodiment 18 of the invention will be described with reference to FIG. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In the present embodiment, the communication start determination unit 15 uses the history information of the positioning result stored in the positioning history storage unit 18 and when the number of GPS satellites captured at the previous positioning is less than the predetermined number n of satellites. Changes the judgment condition for judging the necessity of communication so as to increase the possibility of communication.

FIG. 18 is a flow chart for explaining the judging operation by the communication start judging unit 15.
5 checks the history information of the positioning result stored in the positioning history storage unit 18 (S84), and the G captured during the previous positioning is checked.
The number of PS satellites is compared with a predetermined number of satellites n (S85),
If the number of captured GPS satellites is greater than or equal to a predetermined number n of satellites, the determination condition is a normal condition, and if less than the predetermined number n of satellites, the necessity of communication is increased so that the possibility of starting communication increases. The judgment condition for judgment is changed (S86).

As described above, the communication start judgment unit 15 changes the judgment condition so that the possibility of communication becomes high when the number of GPS satellites captured at the time of the previous positioning is smaller than the predetermined number of satellites. If the satellite acquisition situation is poor, the judgment conditions are changed to increase the possibility of communication, increasing the chances of acquiring satellite information from the base station, so sufficient satellite information can be obtained. The positioning time can be shortened and the positioning accuracy can be improved.

For example, when the communication start judging unit 15 judges the necessity of communication by using the ratio between the number of GPS satellites existing in the sky and the number of effective ephemeris stored in the satellite information storage unit 13, Normally, when the ratio is 80% or less, the communication is started, whereas when the number of satellites captured at the time of the previous positioning is smaller than the predetermined satellite value n, the judgment criterion is made stricter and the ratio is 90. The possibility of communication can be increased by starting communication when the value is less than or equal to%. When the communication start determination unit 15 determines the necessity of communication using the number of captured GPS satellites, the communication is normally started when the number of captured satellites is 3 or less, whereas the previous positioning is performed. When the number of satellites captured at times is smaller than the predetermined satellite value n, the possibility of communication can be increased by starting communication when the number of captured satellites is 4 or less.
Further, when the communication start determination unit 15 determines the necessity of communication by using the C / N ratio of the signal from the captured GPS satellite, the communication is normally started when the C / N ratio is 17 or less. On the other hand, if the number of satellites captured at the time of the previous positioning is less than the predetermined satellite value n, communication is started when the C / N ratio is 20 or less to increase the possibility of communication. You can

Further, the communication start judging section 15 judges the necessity of communication after performing the above-mentioned processing and determining the judgment condition. The judgment condition is the judgment condition described in the second to fifteenth embodiments. Any of the above conditions may be used, and the determination may be performed a plurality of times.

(Embodiment 19) Embodiment 19 of the present invention will be described with reference to FIG. Since the configuration of the position measurement system of this embodiment is the same as that of the first embodiment, the same components are designated by the same reference numerals, and illustration and description thereof will be omitted.

In this embodiment, the communication start determination unit 15 uses the history information of the positioning result stored in the positioning history storage unit 18, and the error rate at the time of decoding the navigation message at the previous positioning is less than the predetermined reference value r. If it is also high, the judgment condition for judging the necessity of communication is changed so that the possibility of communication becomes high.

FIG. 19 is a flow chart for explaining the judging operation by the communication start judging section 15.
5 checks the history information of the positioning result stored in the positioning history storage unit 18 (S87), compares the error rate at the time of decoding the navigation message at the time of the previous positioning with the predetermined reference value r (S88), If the error rate is equal to or lower than the reference value r, the determination condition is set as a normal condition, and if the error rate is higher than the reference value r, the determination condition for determining the necessity of communication is changed so as to increase the possibility of starting communication ( S89).

As described above, the communication start judgment unit 15 changes the judgment condition so that the possibility of communication becomes high when the error rate at the time of decoding the navigation message at the previous positioning is higher than the predetermined reference value r. Therefore, when the GPS satellite acquisition condition is poor, the chances of acquiring satellite information are increased by changing the determination conditions so that the possibility of communication increases, so sufficient satellite information can be obtained. Therefore, the positioning time can be shortened and the positioning accuracy can be improved.

For example, when the communication start judging unit 15 judges the necessity of communication by using the ratio between the number of GPS satellites existing in the sky and the number of effective ephemeris stored in the satellite information storage unit 13, Normally, communication is started when the ratio is 80% or less, whereas communication is started when the ratio is 90% or less when the decoding error rate at the previous positioning is higher than the reference value r. Thus, the possibility of communication can be increased. In addition, the communication start determination unit 15
When the necessity of communication is determined using the number of captured GPS satellites, communication is normally started when the number of captured satellites is 3 or less, whereas the decoding error rate at the time of the previous positioning is the reference value. If it is higher than r, the possibility of communication can be increased by starting the communication when the number of traps is 4 or less. Further, the communication start determination unit 15 captures the G
When the necessity of communication is determined using the C / N ratio of the signal from the PS satellite, the communication is normally started when the C / N ratio is 17 or less, whereas the decoding error rate at the time of the previous positioning is determined. Is higher than the reference value r, the possibility of communication can be increased by starting the communication when the C / N ratio is 20 or less.

Further, the communication start judging section 15 judges the necessity of communication after performing the above-mentioned processing and determining the judgment condition. The judgment condition is the judgment condition described in the second to fifteenth embodiments. Any of the above conditions may be used, and the determination may be performed a plurality of times.

[0109]

As described above, the invention of claim 1 is GP
A first satellite signal receiving unit that receives satellite signals transmitted from S satellites, and a first satellite signal receiving unit that receives satellite information transmitted from the outside.
Communication unit, a first satellite information storage unit that stores satellite information received by the first communication unit, a satellite signal received by the first satellite signal reception unit, and a satellite stored in the first satellite information storage unit. A first GPS receiver including a position calculation unit that calculates a current position based on information, a second satellite signal reception unit that receives satellite signals transmitted from GPS satellites, and a second satellite signal reception unit. The second satellite information storage unit that stores satellite information obtained from the satellite signal received by the first communication unit and the first communication unit communicate with each other, and the satellite information stored in the second satellite information storage unit is stored in the first satellite information storage unit. A second GPS receiver including a second communication unit for transmitting to the first communication unit, and the first GPS receiver includes a G
Based on at least one of the information indicating the storage status of satellite information related to the PS satellite, the information indicating the acquisition status, the time information, or the history information of the positioning result, between the first and second communication units. A communication start determination unit that determines whether to start communication is provided, and communication is performed between the first communication unit and the second communication unit only when the communication start determination unit determines to start communication. Characterized in that the satellite information stored in the second satellite information storage unit is acquired from the second GPS receiver.
In the second GPS receiver, satellite information related to GPS satellites is obtained from the satellite signals received by the second satellite signal receiving unit and stored in the second satellite information storage unit.
In the receiver, the satellite information is acquired from the second GPS receiver and stored in the first satellite information storage unit by communicating between the first communication unit and the second communication unit, and the position information is stored in the first satellite information storage unit. The arithmetic unit calculates the satellite signal obtained by the first satellite signal receiving unit and the first satellite signal.
Since the current position is calculated using the satellite information stored in the satellite information storage unit of, the time required for position measurement can be shortened by acquiring the satellite information from the second GPS receiver, and the positioning accuracy and Only when the positioning probability can be expected to improve and the communication start determination unit determines to start communication,
Since communication is performed with the second GPS receiver, there is an effect that the communication fee can be reduced by reducing the number of times of communication as compared with the case of performing communication at each positioning.

According to a second aspect of the present invention, in the first aspect of the invention, the number of effective ephemeris stored in the satellite information storage unit is used as the information indicating the storage state of the satellite information,
If the number of valid ephemeris is less than the reference value, the communication start determination unit starts communication between the first and second communication units. Since it determines that sufficient positioning information has been obtained and does not communicate with the base station, it can reduce the number of times of communication and reduce communication charges without deteriorating positioning time and positioning accuracy. effective.

According to a third aspect of the present invention, in the first aspect of the invention, the number of effective ephemeris stored in the satellite information storage unit and the number of GPS satellites existing in the sky are used as information indicating the storage state of the satellite information. If the ratio of the number of effective ephemeris to the number of GPS satellites existing in the sky is lower than the reference value, the communication start determination unit starts the communication between the first and second communication units. Characterized by
When the ratio of the number of valid ephemeris among the GPS satellites existing in the sky is equal to or higher than the reference value, it is determined that sufficient positioning information is obtained, and communication with the base station is not performed. There is an effect that the number of communications can be reduced and the communication fee can be reduced without deteriorating the time and the positioning accuracy.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the number of effective ephemeris stored in the satellite information storage unit is set to GP as the information indicating the storage state of the satellite information.
If the value weighted by the elevation angle of the S satellite is used and the value weighted by the elevation angle of the GPS satellite for the number of valid ephemeris is smaller than the reference value, the communication start determination unit determines between the first and second communication units. When the value obtained by weighting the number of effective ephemeris by the elevation angle of the GPS satellite is equal to or greater than the reference value,
GPS with higher elevation angle among GPS satellites existing in the sky
Since it can be determined that the satellite holds valid ephemeris and holds information that is advantageous for position measurement, the positioning time and positioning accuracy will be deteriorated by not communicating with the base station. In addition, the communication fee can be reduced by reducing the number of times of communication.

According to a fifth aspect of the present invention, in the first aspect of the present invention, the DOP value of the GPS satellite in which the effective ephemeris is stored in the satellite information storage unit is used as the information indicating the storage state of the satellite information, and the communication is performed. The start determination unit is characterized by starting communication between the first and second communication units if the DOP value is larger than the reference value, and if the DOP value is less than or equal to the reference value, the GPS with ephemeris is effective. Since it can be determined that the satellites are in a good condition and sufficient positioning information has been obtained, by not communicating with the base station, positioning times and positioning accuracy are not deteriorated, and the number of communication There is an effect that the communication charge can be reduced by reducing the number of charges.

According to a sixth aspect of the present invention, in the first aspect of the invention, a value obtained by weighting the number of GPS satellites captured by the elevation angle is used as the information representing the state of acquisition of GPS satellites.
The communication start determination unit starts communication between the first and second communication units when the value obtained by weighting the number of GPS satellites captured by the elevation angle is smaller than the reference value. If the value obtained by weighting the number of acquisitions by the elevation angle is equal to or greater than the reference value, it can be determined that a large number of GPS satellites with a high elevation angle are acquired, and in such a case G
Since it can be determined that the navigation message can be easily obtained by decoding the signal from the PS satellite, the number of communications can be increased without deteriorating the positioning time and the positioning accuracy by not communicating with the base station. There is an effect that the communication fee can be reduced by reducing the amount.

According to a seventh aspect of the present invention, in the first aspect of the present invention, the DOP value of the captured GPS satellite is used as the information indicating the capture status of the GPS satellite, and the communication start determining unit is
If the DOP value is larger than the reference value, the communication between the first and second communication units is started. If the DOP value obtained for the captured GPS satellite is less than the reference value, it is captured. The location of GPS satellites is good,
Since it can be determined that sufficient positioning information has been obtained, in such a case, by not communicating with the base station,
There is an effect that the number of communications can be reduced and the communication fee can be reduced without deteriorating the positioning time and the positioning accuracy.

According to the invention of claim 8, in the invention of claim 1, the elevation angle of the GPS satellite first captured at the start of positioning is used as the information representing the capture status of the GPS satellite, and the communication start determining unit first If the elevation angle of the captured GPS satellite is higher than the reference angle, communication between the first and second communication units is started, and the elevation angle G is equal to or less than the reference angle.
GPS satellites whose elevation angle is higher than the reference angle are easier to capture than PS satellites. Therefore, if the elevation angle of the GPS satellite first captured is less than or equal to the reference angle, the GPS satellite whose elevation angle is higher than the reference angle is captured. Since it can be determined that it is possible and therefore sufficient positioning information can be obtained, in such a case, the communication with the base station is not performed, so that the positioning time and the positioning accuracy are not deteriorated and the communication is performed. There is an effect that the communication fee can be reduced by reducing the number of times.

According to a ninth aspect of the invention, in the first aspect of the invention, the elapsed time from the previous positioning is used as the time information,
The communication start determination unit starts communication between the first and second communication units when the elapsed time is longer than the reference time, and when the elapsed time is less than or equal to the reference time, the previous positioning is performed. Since it can be determined that the satellite information used at the time is valid, in such a case, by not communicating with the base station, the positioning time and positioning accuracy are not deteriorated,
There is an effect that the number of communications can be reduced and the communication fee can be reduced.

According to a tenth aspect of the present invention, in the first aspect of the present invention, the remaining time of the effective time of the ephemeris is used as the time information, and the communication start determining unit determines whether the remaining time is shorter than the reference time. The communication between the second communication units is started, and if the remaining time of the effective time is shorter than the reference time, the communication between the first and second communication units is started to perform positioning. If sufficient satellite information can be obtained and the remaining valid time is equal to or longer than the reference time, it can be determined that sufficient positioning information has been obtained. By not performing communication between the communication devices, there is an effect that the communication frequency can be reduced and the communication fee can be reduced without deteriorating the positioning time and the positioning accuracy.

According to the invention of claim 11, in the invention of claim 1, the remaining time of the effective time of the ephemeris is used as the time information, and the signal from the GPS satellite acquired is used as the information indicating the acquisition status of the GPS satellite. Using the C / N ratio, the communication start determination unit starts communication between the first and second communication units when the remaining time is shorter than the reference time and the C / N ratio is equal to or less than the reference value. When the remaining time of the effective time of the ephemeris is shorter than the reference time and the C / N ratio is equal to or less than the reference value, the communication between the first and second communication units is started. Therefore, if the satellite information sufficient for positioning can be acquired, and the C / N ratio of the signal is higher than the reference value even when the remaining time of the effective time of the ephemeris is shorter than the reference time, the first satellite signal By the receiver It can be determined that the satellite information can be extracted from the PS satellite signal, and in such a case, communication is not performed with the base station, so that the number of times of communication can be reduced without deteriorating the positioning time and the positioning accuracy. According to the invention of claim 12, which has an effect of reducing the communication charge, in the invention of claim 1, the previous positioning result is used as the history information of the positioning result, and the communication start determining unit determines if the previous positioning has not been performed. It is characterized in that the communication between the first and second communication units is started, and if the positioning has failed at the previous positioning, by starting the communication between the first and second communication units, If sufficient satellite information for positioning can be obtained and positioning is successful at the previous positioning, it can be determined that the positioning situation is good. By not communicating, positioning time Without causing deterioration of the positioning accuracy, the effect of reducing the communication charge with less number of communications.

According to a thirteenth aspect of the present invention, in any one of the first to twelfth aspects of the present invention, the previous positioning result is used as the history information of the positioning result, and the communication start determining unit determines if the previous positioning has not been performed. , Characterized in that the judgment condition for judging the necessity of communication is changed so that the possibility of communication becomes high,
If the positioning has failed during the previous positioning, it can be determined that the GPS satellite acquisition status is bad. In such a case, the determination conditions for determining the necessity of communication are changed so that the possibility of communication increases. By doing so, it is possible to increase the chances of acquiring satellite information from the second GPS receiver, obtain sufficient satellite information, shorten the positioning time, and improve the positioning accuracy. .

According to a fourteenth aspect of the present invention, in any one of the first to twelfth aspects of the present invention, the number of GPS satellites captured at the time of the previous positioning is used as the history information of the positioning result, and the communication start determining unit determines the previous positioning. When the number of GPS satellites captured at a time is less than a predetermined number of satellites, the determination condition for determining the necessity of communication is changed so that the possibility of communication becomes high. If the number of satellites is less than the predetermined number of satellites, it can be determined that the GPS satellite acquisition status is poor. In such a case, the determination condition for determining the necessity of communication is set so as to increase the possibility of communication. By changing it, it is possible to increase the chances of acquiring satellite information from the second GPS receiver, obtain sufficient satellite information, shorten the positioning time, and improve the positioning accuracy. There is a result.

According to a fifteenth aspect of the present invention, in any one of the first to twelfth aspects of the present invention, the error rate at the time of decoding the navigation message from the GPS satellite captured at the previous positioning is used as the history information of the positioning result. When the error rate is higher than the reference value, the communication start determination unit changes the determination condition for determining the necessity of communication so as to increase the possibility of communication. G
If the error rate at the time of decoding the navigation message from the PS satellite is higher than the reference value, it can be determined that the GPS satellite acquisition status is bad, and in such a case, communication is performed to increase the possibility of communication. By changing the determination condition for determining the necessity of the satellite, it is possible to increase the chances of acquiring satellite information from the second GPS receiver, obtain sufficient satellite information, shorten the positioning time, and improve the positioning accuracy. There is an effect that can improve.

[Brief description of drawings]

FIG. 1 is a block diagram of a position measuring system according to a first embodiment.

FIG. 2 is a flowchart illustrating the operation of the second embodiment.

FIG. 3 is a flowchart illustrating the operation of the third embodiment.

FIG. 4 is a flowchart illustrating the operation of the fourth embodiment.

FIG. 5 is a flowchart illustrating an operation of the fifth embodiment.

FIG. 6 is a flowchart illustrating the operation of the sixth embodiment.

FIG. 7 is a flowchart illustrating an operation of the seventh embodiment.

FIG. 8 is a flowchart illustrating the operation of the eighth embodiment.

FIG. 9 is a flowchart illustrating the operation of the ninth embodiment.

FIG. 10 is a flowchart illustrating the operation of the tenth embodiment.

FIG. 11 is a flowchart illustrating the operation of the eleventh embodiment.

FIG. 12 is a flowchart illustrating the operation of the twelfth embodiment.

FIG. 13 is a flowchart illustrating the operation of the thirteenth embodiment.

FIG. 14 is a flowchart illustrating the operation of the fourteenth embodiment.

FIG. 15 is a flowchart illustrating the operation of the fifteenth embodiment.

FIG. 16 is a flowchart illustrating the operation of the sixteenth embodiment.

FIG. 17 is a flowchart illustrating the operation of the seventeenth embodiment.

FIG. 18 is a flowchart illustrating the operation of the eighteenth embodiment.

FIG. 19 is a flowchart illustrating the operation of the nineteenth embodiment.

[Explanation of symbols]

10 First GPS receiver 11 GPS satellite signal receiver 12 Position calculator 13 Satellite information storage 14 Communications department 15 Communication start determination unit 20 Second GPS receiver 31-33 GPS satellites

Continued front page    (72) Inventor Kazuo Yamada             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Masahito Fukuda             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Takuya Sueto             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Ikuo Tsujimoto             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Kenji Okuno             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Kazuhiro Kawamoto             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Sadae Satake             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Koji Sakamoto             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Kenji Kuramae             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company F term (reference) 5J062 AA01 AA02 BB01 BB05 CC07                       DD12 DD22 DD24 EE04 FF01

Claims (15)

[Claims] 1. A first satellite signal receiving section for receiving satellite signals transmitted from GPS satellites, a first communication section for receiving satellite information transmitted from the outside, and satellite information received by the first communication section. A first satellite information storage unit that stores the position information, a position calculation unit that calculates a current position based on the satellite signal received by the first satellite signal reception unit and the satellite information stored in the first satellite information storage unit, A first GPS receiver, a second satellite signal receiving section for receiving satellite signals transmitted from GPS satellites, and a second satellite signal receiving section for storing satellite information obtained from the satellite signals received by the second satellite signal receiving section. From the second satellite information storage unit and the second communication unit that communicates with the first communication unit and transmits the satellite information stored in the second satellite information storage unit to the first communication unit. The second GPS receiver is Based on at least one of the information indicating the storage status of satellite information related to the S satellite, the information indicating the acquisition status, the time information, and the history information of the positioning result, between the first and second communication units. A communication start determination unit that determines whether to start communication is provided, and communication is performed between the first communication unit and the second communication unit only when the communication start determination unit determines to start communication. A position measurement system characterized by performing and acquiring satellite information stored in a second satellite information storage unit from a second GPS receiver. 2. The number of valid ephemeris stored in the satellite information storage unit is used as the information indicating the storage state of the satellite information, and the communication start determination unit determines that the number of valid ephemeris is less than a reference value. For example, the position measurement system according to claim 1, wherein communication between the first and second communication units is started. 3. The number of effective ephemeris stored in the satellite information storage unit and the number of GPS satellites existing in the sky are used as the information representing the storage status of the satellite information, and the communication start determination unit is in the sky. If the ratio of the number of effective ephemeris to the number of GPS satellites existing in is lower than the reference value,
The position measuring system according to claim 1, wherein communication between the first and second communication units is started. 4. A value obtained by weighting the number of effective ephemeris stored in the satellite information storage unit by the elevation angle of a GPS satellite is used as the information representing the storage status of satellite information,
The communication start determination unit determines that the number of valid ephemeris is GP.
The position measuring system according to claim 1, wherein if the value weighted by the elevation angle of the S satellite is smaller than the reference value, communication between the first and second communication units is started. 5. The effective ephemeris G is stored in the satellite information storage unit as information indicating the storage status of satellite information.
Using the DOP value of the PS satellite, the communication start determination unit
The position measurement system according to claim 1, wherein if the OP value is larger than the reference value, communication between the first and second communication units is started. 6. Information representing the acquisition status of GPS satellites,
A value obtained by weighting the number of captured GPS satellites by the elevation angle thereof is used, and the communication start determining unit determines the first and second communication units if the value obtained by weighting the number of captured GPS satellites by the elevation angle is smaller than a reference value. The position measuring system according to claim 1, wherein communication between the two is started. 7. The information representing the acquisition status of GPS satellites includes:
The DOP value of the captured GPS satellite is used, and if the DOP value is greater than a reference value, the communication start determination unit starts communication between the first and second communication units. Position measurement system described. 8. Information representing the acquisition status of GPS satellites,
Using the elevation angle of the GPS satellite first captured at the start of positioning,
The position measurement according to claim 1, wherein the communication start determination unit starts communication between the first and second communication units when the elevation angle of the first captured GPS satellite is higher than the reference angle. system. 9. The time information used is the elapsed time from the previous positioning, and the communication start determination unit starts communication between the first and second communication units if the elapsed time is longer than the reference time. The position measuring system according to claim 1, wherein 10. The remaining time of the effective time of the ephemeris is used as the time information, and the communication start determining unit starts communication between the first and second communication units if the remaining time is shorter than the reference time. The position measuring system according to claim 1, wherein 11. The remaining time of the effective time of the ephemeris is used as the time information, and C of the signal from the GPS satellite that is being acquired is used as the information indicating the acquisition status of the GPS satellite.
/ N ratio, the communication start determination unit starts communication between the first and second communication units when the remaining time is shorter than the reference time and the C / N ratio is equal to or less than the reference value. The position measuring system according to claim 1, wherein 12. The previous positioning result is used as the history information of the positioning result, and the communication start determination unit starts communication between the first and second communication units when the previous positioning has not been performed. The position measuring system according to claim 1. 13. The previous positioning result is used as the history information of the positioning result, and the communication start judging unit judges whether or not the communication is necessary so as to increase the possibility of communication when the previous positioning has not been carried out. The position measuring system according to claim 1, wherein the condition is changed. 14. The number of GPS satellites captured at the time of the previous positioning is used as the history information of the positioning result, and the communication start determining unit communicates when the number of GPS satellites captured at the time of the previous positioning is less than a predetermined number of satellites. 13. The position measurement system according to claim 1, wherein the determination condition for determining the necessity of communication is changed so that the possibility of communication is increased. 15. When the error rate at the time of decoding the navigation message from the GPS satellite captured at the time of the previous positioning is used as the history information of the positioning result, the communication start judging unit determines that the error rate is higher than the reference value. 13. The position measurement system according to claim 1, wherein the determination condition for determining the necessity of communication is changed so that the possibility of communication increases.