JPH10104335A - Position measurement system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position measurement system wherein lower and miniaturization can be performed and a position can be measured at practical precision. SOLUTION: In the side of a center, a correction information calculation device 2 finds correction information for correcting a measured position by GPS on the basis of the measured position of a receiver 1 for GPS and a constant point survey position which is a previously measured exact position, an adding device extracts difference information M showing only a difference between latitude and longitude components from the correction information at prescribed time intervals to transmit it to the side of a base station facility. The difference information M is transmitted as a message of a pager 12. In a discrimination device 13 in a position measuring device 10, the difference information M is extracted from the message which the pager 12 receives, and an exact position is obtained at high precision by a correction processor 14 on the basis of measuring information of the difference information M and the receive 11 for GPS.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position measuring system suitable for use in, for example, a car navigation system.

[0002]

2. Description of the Related Art In recent years, GPS (Global Positioning Sys
tem) -based car navigation systems are becoming widespread. Currently, most of the car navigation systems on the market are GPS receivers (hereinafter referred to as “GP”).
In addition to the "S receiver"), the position of the vehicle is measured using a gyro, a vehicle speed sensor, and the like. The reason why a gyro, a vehicle speed sensor, and the like are used together is that an error of about 100 to 300 m occurs in a measurement position in a system employing only a GPS receiver, which is not practical especially in a densely populated road area such as an urban area.

Further, as a system for improving the accuracy of position measurement using GPS without using a gyro or a vehicle speed sensor, a GP at a fixed point surveyed reference point (center) is used.
The information for correcting the position measured by S is obtained at sufficiently short time intervals, this correction information is notified to each car navigation system, and the own position received via the GPS receiver in each car navigation system is described above. A system that corrects using correction information (so-called differential GPS) has been developed.

[0004] In this system, correction information is transmitted to each car navigation system by connecting the car navigation system to a mobile phone, making a call connection from the mobile phone to a reference point center, establishing a line, and via this line. This is performed by continuously notifying the latest correction information from the center side to the mobile phone (car navigation system) side at predetermined time intervals.

[0005]

As described above, in the conventional car navigation system, it is necessary to use a gyro, a vehicle speed sensor, and the like, which is one of the factors that hinder the cost reduction and size reduction of the system. Had become.

On the other hand, in a system for correcting a measurement position by GPS using correction information obtained using a mobile phone,
Although a gyro, a vehicle speed sensor, and the like are not required, it is necessary to keep establishing a line with the center, and there is a problem that communication cost becomes extremely high. Of course, if a PHS (Personal Handy-phone System) is used instead of a mobile phone, communication costs can be reduced somewhat, but it is highly likely that the mobile phone will not be usable in places other than urban areas.
In the first place, it is not suitable for a system mounted on a high-speed moving vehicle such as a car navigation system.

In recent years, a system for connecting a portable computer and a portable telephone to transmit character data, numerical data, voice data, image data, and the like has been becoming widespread. It is also conceivable to use the position measurement system using the correction information together with the position measurement system. However, at present, both systems have been developed separately and no consideration has been given to cooperation between the two systems.

The present invention has been made under such a background, and it is an object of the present invention to provide a position measuring system which can reduce the cost and size and can measure a position with a practical accuracy. The purpose is.

[0009]

According to a first aspect of the present invention, there is provided a position measuring system, comprising: a transmitting-side facility for transmitting information for correcting a position measured by a GPS; Receiving equipment that receives the transmitted information and corrects and outputs the measured position by GPS based on the information, and the transmitting equipment determines a position at a reference point based on a radio wave received from a GPS satellite. A first GPS receiver to be measured, and correction for obtaining correction information for correcting a measurement position by GPS based on the position measured by the first GPS receiver and the fixed point survey position of the reference point. Information calculating means, adding means for extracting difference information representing only the difference between the latitude and longitude components from the correction information in a first cycle, and using the difference information as a message of a wireless call receiver A base station equipment for transmitting at a second cycle equal to or longer than the first cycle, wherein the receiving-side equipment measures a position at a measurement point based on a radio wave received from a GPS satellite. A paging receiver that receives a message and outputs a received message; an extracting unit that extracts and outputs the difference information from the received message output from the paging receiver; and the second GPS receiver And a correction processing unit for obtaining and outputting the position of the measurement point based on the position measured in step (a) and the difference information output from the extraction unit.

[0010] According to a second aspect of the present invention, in the position measurement system according to the first aspect, the base station equipment sends a message comprising the difference information to at least one of the paging receivers in a predetermined group. It is characterized by broadcasting. According to a third aspect of the present invention, in the position measuring system according to the second aspect, a plurality of the groups are provided, and the base station equipment makes the second cycle different for each of the groups.

According to a fourth aspect of the present invention, in the position measuring system according to any one of the first to third aspects, the receiving-side equipment is provided with the radio paging receiver detachably, and when the radio paging receiver is mounted. A predetermined signal is supplied to the radio paging receiver, and the radio paging receiver outputs a reception message when the predetermined signal is supplied. According to a fifth aspect of the present invention, in the position measuring system according to any one of the first to fourth aspects, the extracting unit extracts the difference information and other information from a received message output from the wireless call receiver. Then, these information are output separately.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. A: Configuration of Embodiment FIG. 1 is a block diagram showing the configuration of a system in which a position measurement system according to an embodiment of the present invention is applied to a car navigation system. The upper left middle part shows the configuration of the base station equipment that notifies the difference information included in the correction information, and the lower half of the figure shows the configuration of the car navigation system side (vehicle side) that performs high-accuracy position measurement using the difference information. ing. Note that the correction information of the measurement position by the GPS enables high-precision position correction when using the same GPS satellite as the point (reference point) from which the correction information was obtained.
The center side should be arranged at an interval of about 300 km.

On the center side, a GPS receiver 1 has an antenna 1a, receives radio waves from a plurality of GPS satellites via the antenna 1a, and determines its own position (latitude / longitude) based on the received radio waves. ) (Hereinafter referred to as "reference GPS position") P0 is obtained and output. Usually the reference G
The received radio waves used to determine the PS position P0 are four or eight radio waves extracted in order of signal level.

2 is a GP determined in advance by fixed point surveying.
Reference fixed point position of S receiver 1 (more precisely, antenna 1
a position) a correction information calculating device that holds E0
The difference information M is calculated by subtracting the latitude / longitude component of the reference fixed point position E0 from the latitude / longitude component of the reference GPS position P0 output from the PS receiver 1 and outputs correction information including the difference information M. . The GPS receiver 1 and the correction information calculation device 2 use the above-described mobile phone to perform GP
The same as that used in the system for correcting the position measured by S.

Reference numeral 3 denotes an additional device, which is a correction information calculating device 2.
Extract only the difference information M from the correction information output from
This is sent to the base station equipment via a packet switching network, a telephone line network, a dedicated line, or the like. The difference information M has such a size that it can be transmitted and received without being divided by a pager (wireless call receiver), and in the present embodiment, the update time interval of the correction value in each navigation system is 10 seconds to 30 seconds.
In this case, the difference information M is transmitted via a packet communication network which can minimize the communication cost (and the capital investment).

On the base station equipment side, 4 is a central station that encodes information supplied from various communication networks and outputs it as a message MS, and 5 is a message M supplied from the central station 4.
S is a base station that transmits S from an antenna 5a. In addition to the functions of a normal central station and a base station, both functions of outputting a common message to a preset group of pagers, alphabets and numerals , Symbols, katakana, hiragana, kanji, and pure bit strings (transparent data).

On the other hand, on the vehicle side, reference numeral 10 denotes a position measuring device that measures its own accurate position E based on a received radio wave from a GPS satellite and a received message MS, and 20 denotes a GPS.
Is a user interface for presenting information based on the position E measured by the receiver 10 to the user.

In the GPS receiver 10, reference numeral 11 denotes a GP.
This is a GPS receiver similar to the S receiver 1, which includes an antenna 11 a and has four (or 8)
(Hereinafter referred to as “GPS position”) P based on the received radio waves of the first and second positions. 12 is GP
This is a pager detachably provided to the S receiver 10 and is mounted at a predetermined position of the GPS receiver 10, that is, when a predetermined signal is externally supplied to the serial input port, The message MS received via the built-in or external antenna 12a is output from the serial output port.

If the contents of the received message MS are visible contents such as alphabets, numbers, symbols, katakana, hiragana, and kanji, the pager 12 displays the contents on its own display panel (for example, a liquid crystal panel or the like). ), And if it is real time information, the time of the built-in clock is corrected based on the real time information. In addition, the pager 12 has a function of storing visible messages among the received messages MS, and a function of selecting and displaying a desired message MS according to a user operation. At this time, if a predetermined signal is supplied to the serial input port from the outside, it has a function of outputting the selected and displayed message MS from the serial output port.

Reference numeral 13 identifies whether or not the message MS output from the serial output port of the pager 12 is transparent data. If the message MS is transparent data, it outputs this from the first output port. Conversely, if it is not transparent data, it is output from the second output port. Reference numeral 14 denotes a correction processing device, which is a measurement GPS output from the GPS receiver 11.
By subtracting the difference information M in the bit string output from the first output port of the identification device 13 from the position P, an accurate position E is obtained.
And outputs it together with a portion other than the difference information M (for example, real time information) in the bit string output from the first output port of the identification device 13. Of course, if only the difference information M exists, only the difference information M is output.

In the correction information calculating device 20, reference numeral 21 denotes control means for controlling the car navigation system.
Each unit is controlled based on an instruction input from the operation unit 22 having an operation element such as a cursor key and a position E output from the correction processing device 14. Reference numeral 23 denotes storage means for storing map information and the like, 24 denotes display means such as a color liquid crystal display, 25 denotes voice synthesis means, and 26 denotes sound generation means such as an amplifier and a speaker.

The control means 21 controls each of the means 23 to 26 so as to realize the function of a general car navigation system. The control means 21 reads out map information corresponding to the position E from the storage means 23, and uses this map information. The display unit 24 displays an image obtained by overlaying an image indicating the current position represented by the position E on the image represented by the display unit 24, and changes information supplied to the display unit 24 according to the operation contents of the operation unit 22. Alternatively, the information relating to the position E is supplied to the voice synthesizing means 25, converted into voice, and generated by the voice generating means 26.

Further, the control means 21 supplies a predetermined signal to the serial input port of the pager 12, obtains the current time based on the real time information and the internal clock supplied along with the position E, and displays the current time. An image representing the current time (for example, “19:59”) is displayed on the image displayed by the means 24.
) Is also provided. Further, the control means 21 converts the alphabetic characters, numbers, symbols, katakana, hiragana, kanji, etc. supplied from the identification device 13 into characters.
An overlay message is displayed on the image displayed by the display means 24, and a voice message indicating that a visible message has been received is output using the voice synthesis means 25 and the sound generation means 26.

B: Settings of the Embodiment Next, settings required before operating the system having the above configuration will be described. When the user of the car navigation system including the position measuring device 10 and the correction information calculating device 20 signs a contract for receiving the message MS including the difference information M with the communication company of the pager 12, the base station equipment side It is set to transmit the message MS including the difference information M to the pager 12 of the user (hereinafter, contract user) at a predetermined cycle.

Specifically, this setting is performed by putting the pager 12 of the contract user into a group for transmitting the message MS including the difference information M. The group for transmitting the message MS including the difference information M is divided into a plurality of groups according to the cycle for transmitting the message MS including the difference information M. The group is selected according to the communication speed and the desired position measurement accuracy.
The relationship between the update cycle of the correction value and the error of the measurement position is as shown in Table 1. The numerical values in Table 1 are 95% measured values in the United States.

[0026]

[Table 1]

In this table, "S / A" is a process for lowering the position measurement accuracy in GPS, and most of the errors in the measurement position by GPS are due to this "S / A". Note that, at the time of high S / A, it means a state where the position measurement accuracy by the GPS is intentionally sharply reduced. It means the state that was made to be.

Generally, the length of a vehicle equipped with a car navigation system is about 5 m (private vehicle) to 10 m or more (truck or the like), so that an error in a measurement position is 5 m to 1 m.
If it is about 0 m, it is sufficiently practical. Therefore, the transmission cycle of the message MS including the difference information M is 10 seconds, 2
Of course, 30 seconds may be used instead of 0 seconds. In the present embodiment, groups corresponding to these three periods are provided, and it is assumed that the contract user has selected a group corresponding to the 30-second period from these groups. It is also assumed that the contract user has made a contract to receive the notification of the real-time information together with the difference information M.

C: Operation Example of Embodiment Next, a specific operation example will be described. (1) Operation on the center side On the center side, the GPS receiver 1 uses the antenna 1a.
, And receives a radio wave from a plurality of GPS satellites, obtains a reference GPS position P0 based on the received radio wave, and supplies it to the correction information calculation device 2. The correction information calculation device 2 uses the reference GPS
The difference information M is calculated by subtracting the latitude / longitude component of the reference fixed point position E0 from the latitude / longitude component of the position P0, and information including the difference information M is supplied to the additional device 3. Since the size of the information supplied from the correction information calculating device 2 is too large to be transmitted to the pager at intervals of several tens of seconds, the additional device 3 extracts only the difference information M from the information and transmits it to the packet switching network. A predetermined time interval to the base station equipment side via (for example,
(Every 10 seconds).

(2) Operation on Base Station Equipment Side On the base station equipment side, the central station 4 and the base station 5
The data supplied via the packet communication network, the telephone network, and the dedicated line is transmitted to the designated destination pager as a message MS. At this time, the central station 4 and the base station 5
Transmits the message MS including the difference information M to the pagers in each group at a speed and a time interval corresponding to each group based on the information on the groups described above. Further, in this message M, addition / non-addition of real time information is performed according to the group. Note that transmission of a normal message MS that does not include the difference information M is performed as usual.

(3) Operation on the Vehicle Side The pager 12 on the vehicle side receives the message MS containing the difference information M at the time interval (here, 30 second interval) of the group to which the pager 12 belongs, and normally at a given timing. Is received. However, since the use form of the received information differs depending on the state of the pager 12, the cases will be described separately.

When the pager 12 is not mounted On the vehicle side, when the pager 12 is not mounted on the GPS receiver 10, the car navigation system can also perform the navigation processing based only on the GPS position. However, as described above, since the position measurement accuracy using only the GPS is extremely low, the navigation system is not actually used.

On the other hand, if the received message is visible, the pager 12 displays it on the display panel. Of course, if the pager 12 can output a sound, a predetermined operation is performed to output a sound corresponding to the message MS. As described above, the contract user can perform normal message reception using the pager 12.

When the pager 12 is mounted, on the other hand, when the pager 12 is mounted on the GPS receiver 10, a predetermined signal is sent from the control means 21 to the pager 12 via the serial input port. Supplied,
The pager 12 outputs the received message MS from a serial output port. At this time, if the received message MS is visible, the content is displayed on its own display panel. If the received message MS is real time information, the time of the internal clock is set based on the real time information. to correct. The message MS output from the pager 12 is
Are separated or classified into transparent data and other data, and are output from a first output port and a second output port, respectively.

On the other hand, the GPS receiver 11 obtains the GPS position P, which is the position of the vehicle, and supplies it to the correction processing device 14. In the correction processing device 14, the difference information M is extracted from the bit string output from the first port of the identification device 13, and the accurate position E is obtained by subtracting the difference information M from the measured GPS position P. This position E is supplied to the control means 21 together with the real time information in the bit string output from the first output port of the identification device 13.

The control means 21 performs navigation processing based on the position E. At this time, since the error of the current position displayed on the display means 24 is about 5 m to 8 m, the user can operate the vehicle based on the measurement position with sufficient accuracy for practical use. Further, the control means 21 obtains an accurate current time based on the real time information supplied from the correction processing device 14 and the internal clock. The display / non-display of the current time can be designated by the operation means 22. At the time of display, an image representing the current time is displayed on the image displayed on the display means 24 in an overlay manner.

The data output from the second output port of the identification device 13 is supplied to the control means 21.
The display means 24 performs overlay display. When the data is audio data, the control means 21
The voice represented by the data is output via the voice synthesis unit 25 and the sound generation unit 26. Further, control means 2
1 is that when a predetermined operation is performed on the operation unit 22,
Using the voice synthesizing means 25 and the sound generating means 26, the data (numerical strings, character strings, etc.) being displayed is read out.

D: Conclusion As described above, according to the above-described embodiment, only the difference information M is extracted by the additional device 3 and can be transmitted to the pager 12 at a predetermined time interval. Even so, it is possible to realize a sufficiently practical position measurement accuracy. Further, by using the pager 12 instead of the gyro and the vehicle speed sensor or the mobile phone on the car navigation system side, it is possible to reduce the cost and size.

Further, since the pager 12 is made detachable in the GPS receiver 10, there is an advantage that the pager 12 can be used alone. Further, since a predetermined signal is sent from the control means 21 to the serial input port of the pager 12, the pager 12 can recognize its own state (wearing / non-wearing).
The operation mode can be automatically switched between when the camera is mounted and when the camera is not mounted. Therefore, the labor required for the user can be reduced.

Further, since the real time information is notified together with the difference information M, the user can know the extremely accurate time. Further, since the time and the message can be displayed on the display means 24, it is much easier to see them than to see them on the small display panel of the pager 12. In addition, since it is possible to use a voice synthesizing unit, a sound generating unit, and the like that are difficult to attach to the pager 12 because the circuit may be complicated, large, and high in cost, the received message may be used in various forms. Can be. Further, even if a message including the difference information M is received, the message is not stored in the pager 12, so that it is possible to avoid a situation where the storage capacity is immediately exceeded and the previous message disappears.

In the above-described embodiment, an example in which the present invention is applied to a car navigation system has been described. However, not only the position management of transportation such as a bus but also the operation presupposed to be carried, for example, gas / water supply etc. Check the location of burial work,
It can be applied to various uses such as snowfall / snow removal status management integrated with a camera, simple surveying, and confirmation of the position of a person by carrying.

[0042]

As described above, according to the present invention,
In order to use only the difference information in the correction information for correcting the measurement position by the GPS, a radio paging receiver can be used in the receiving equipment. Therefore, the communication cost can be significantly reduced as compared with the case where a mobile phone is used. Further, if the present invention is applied to a car navigation system, high-accuracy position measurement can be performed without the need of a gyro, a vehicle speed sensor, and the like, so that cost reduction and miniaturization can be realized.

Also, by broadcasting the message,
The burden on the base station side equipment can be reduced (claim 2). In addition, by providing a plurality of groups and making the notification intervals of the difference information different in each group, there is an effect that various services according to the user's request can be provided (claim 3).

Further, by making the radio pager detachable, the radio pager can be used for its intended purpose, and one radio pager can be used for two different purposes. . Further, since the radio pager can identify its own detachment,
Switching between two applications can be easily performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a system in which a position measurement system according to an embodiment of the present invention is applied to a car navigation system.

[Explanation of symbols]

 1, 11: GPS receiver, 2: Correction information calculation device, 3: Additional device, 4: Central station, 5: Base station, 12: Pager, 13: Identification device, 14: Correction processing device 21 Control means.

Claims (5)

[Claims] 1. A transmission-side facility for transmitting information for correcting a GPS-measured position, a reception for receiving information transmitted from the transmitting side, correcting a GPS-measured position based on the information, and outputting the corrected position. A first GPS receiver that measures a position at a reference point based on a received radio wave from a GPS satellite, and the first GP.
Correction information calculating means for obtaining correction information for correcting the measurement position by GPS based on the position measured by the receiver for S and the fixed-point survey position of the reference point; and a difference between the latitude and longitude components from the correction information. Means for extracting difference information representing only the first period in a first period, and using the difference information as a message of a radio paging receiver in a second period equal to or longer than the first period.
And a base station facility for transmitting at a cycle of the second station. The receiving facility comprises: a second GPS receiver for measuring a position based on a received radio wave from a GPS satellite at a measurement point; A radio call receiver to output,
Extracting means for extracting and outputting the difference information from the received message output from the radio call receiver; and a position measured by the second GPS receiver and the difference information output from the extracting means. And a correction processing means for calculating and outputting the position of the measurement point based on the position measurement system. 2. The location measurement according to claim 1, wherein the base station equipment broadcasts a message including the difference information to at least one of the radio paging receivers in a preset group. system. 3. The position measurement system according to claim 2, wherein a plurality of said groups are provided, and said base station equipment makes said second cycle different for each of said groups. 4. The reception-side facility is provided with the radio paging receiver in a detachable manner, and supplies a predetermined signal to the radio paging receiver when the radio paging receiver is attached. The position measurement system according to any one of claims 1 to 3, wherein a reception message is output when said signal is supplied. 5. The apparatus according to claim 1, wherein the extracting unit extracts the difference information and other information from a received message output from the wireless call receiver, and outputs the information separately. 5. The position measuring system according to any one of 1 to 4.