JPH04174387A - Monitor of moving body - Google Patents

Abstract

PURPOSE:To improve position measuring accuracy by measuring the positions of a plurality of moving bodies on the basis of radio waves fed from a GPS satellite and monitoring the moving states of the moving objects on the basis of measurement results. CONSTITUTION:A monitor is made up of vehicle carried apparatuses 11 loaded on respective vehicles and a ground apparatus 21 installed in a control office. The reception antenna 12 and the receiver 13 of the vehicle carried apparatus 11 receive radio waves m1 - m3 from a GPS satellite, an central processing unit 14 calculates the position of the vehicle by receiving the received signal of the receiver 13 and forms transmission data and image data. A transmitter 15 and the antenna 16 transmits radio waves d1 to the ground apparatus 21 on the basis of transmission data made in the central processing unit 14. Further, a display unit 17 displays the position of vehicle on the basis of the image data made by the central processing unit 14. On the other hand, the ground apparatus 21 receives the radio waves d1 transmitted from the vehicle carried apparatuses 11 and the radio waves m1 - m3 from the GPS satellite, performs data processing and the display of a result.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to all kinds of moving bodies such as manned vehicles such as buses and taxis, automatic guided vehicles, ships, and aircraft, and is applicable to the movement status of multiple moving bodies. This invention relates to a device that can monitor traffic flow to improve operational efficiency and ensure safety.

[Conventional technology]

Conventionally, there is a system called an AVM system for controlling a plurality of moving objects.

When this system is applied to the operation management of automobiles (taxi) traveling on the road, as shown in Fig. 12, sign posts 1001 with transmitters at main points on the side of the road...
will be placed intermittently. Then, the transmitter of each sign post 1001 sends out a signal indicating the respective position. In-vehicle wireless equipment 10 installed in each automobile 1002...
03 receives the above position signal and sends each vehicle 1002...
. . , and transmits data signals indicating the operating status of each vehicle 1°O2 . . . together with the detected positions to the control office 1004. Control office 10
04, the central equipment 1005 receives these data signals and each vehicle 100 indicated by these data signals
2. Understand the location and operating status of each vehicle 10.
The central device 1005 transmits a signal indicating the operation command for optimizing the operation of 02 . . . to each vehicle-mounted wireless device 1003.

In addition, in recent years, GPS (Global
Positioning systems (global positioning systems) are attracting attention because they have the following advantages:

There is a possibility that radio waves transmitted from 1°GPS satellites can be used free of charge.

2' Since GPS satellites are in orbit around the earth, they are capable of making measurements all over the earth, including the polar regions.

In GPS, at least three or more GPS satellites are launched above the earth, and radio waves transmitted from each GPS satellite are received by a GPS receiver mounted on a mobile object whose position is to be measured. The mobile body then determines the position of the mobile body based on the reception time difference (propagation time difference) of the radio waves transmitted from each GPS satellite, and displays this position as its current position on the screen of the display device installed in the mobile body. That's what I do.

[Problem to be solved by the invention]

In the above AVM system, the position of a moving object is determined by which small area the moving object belongs to divided by a finite number of sign posts, and the accuracy of the position depends on the installation density of the sign posts. For this reason, if the sign posts are sparsely installed, measurement accuracy may be impaired.

Furthermore, since the position of a moving object is captured as the position of a sign post, sign posts must be placed throughout the entire driving area in order to cover the area in which the moving object is traveling. For this reason, the wider the driving area, the more signposts must be installed, and the cost of the device increases as the area becomes wider. For this reason, wide-area operation is costly.

Additionally, since sign posts are fixedly placed on the ground along the travel course of the moving object, there is no particular problem when the travel course of the moving object is relatively fixed, but the layout of the travel course changes frequently. If the parking area is changed or the driving area is expanded, the sign post must be reinstalled or a new sign post must be installed, resulting in poor flexibility and flexibility for layout changes and expansion. .

Furthermore, if airborne objects such as snow, fog, dust, etc. or mud adhere to the sign post, there is a risk of communication failure between the moving object and the sign post, resulting in a lack of reliability of the device.

Furthermore, in order to maintain the function of the sign post, it is necessary to perform maintenance on the sign post in case the sign post is damaged by external enemies due to wind and rain, which is a hassle.

On the other hand, a GPS position measurement system only displays its own position on a display device mounted on a moving body, and cannot know the position of its own moving body in relation to the positions of other moving bodies. For this reason, it has been impossible to achieve operation optimization by monitoring the operation status of multiple moving objects.

The present invention has been made in view of these circumstances, and
By measuring position based on radio waves transmitted from PS satellites, the position measurement accuracy is higher than the conventional method using sign posts, and it can be used for wide area operation at low cost.
Also, it can flexibly respond to changes in the layout of the running course, etc.
Another object of the present invention is to provide a mobile object monitoring device that is highly reliable, maintenance-free, and capable of monitoring a plurality of mobile objects at once.

[Means and effects for solving the problem] Therefore, in the first aspect of the present invention, in a mobile object monitoring device that monitors a plurality of mobile objects based on signals from at least three GPS satellites installed in the air, at least Each of the plurality of mobile objects includes one base station, and a GPS radio wave receiving means for receiving radio waves respectively transmitted from the GPS satellite, and each GPS radio wave received by the GPS radio wave receiving means.
A position calculating means for sequentially calculating the position of the mobile object based on the difference in reception time of radio waves from the satellite, and a transmitting means for transmitting the calculation result of the position calculating means to the base station together with the identification code of the own vehicle. I'm trying to make it easier. Here, the base station includes mobile body position receiving means that receives a transmission signal from the transmission means of the mobile body, and a display that displays the current position of each of the mobile bodies based on the received signal of the mobile body position reception means. Means are provided. The base station also includes a mobile body position receiving means for receiving a transmission signal from the transmitting means of the mobile body, and a position of each of the mobile bodies as a function of time based on the received signal of the mobile body position receiving means. and means for recording.

That is, according to this configuration, the positions of a plurality of moving objects are calculated based on the difference in reception time of radio waves transmitted from each GPS satellite. The positions of these multiple mobile objects are transmitted to the base station. At the base station, the positions of a plurality of moving objects are displayed on a display means. The position of each moving object is also recorded as a function of time.

This allows the operation status of multiple moving objects to be monitored.

Furthermore, in the second aspect of the present invention, the positions of a plurality of moving objects are similarly calculated based on the difference in reception time of radio waves transmitted from each GPS satellite. The position calculation results are stored in a removable storage medium as a function of time for each of the plurality of moving objects. By taking out the storage medium and reading out the stored contents all at once, the operational status of a plurality of moving objects can be monitored.

Further, in the third aspect of the present invention, the plurality of mobile objects includes a reference station whose arrangement position is known, and the plurality of mobile objects have first GPS stations that receive radio waves respectively transmitted from the GPS satellites.
each comprising a radio wave receiving means and a first position calculating means for sequentially calculating the position of the mobile object based on the reception time difference of radio waves from each GPS satellite received by the first GPS radio wave receiving means, The reference station includes a second GPS radio wave receiving means that receives radio waves respectively transmitted from the GPS satellites, and a second GPS radio wave receiving means that receives the radio waves from the respective GPS satellites based on the reception time difference of the radio waves from each GPS satellite. a second position calculation means for calculating the position of the reference station; and correction information creation for creating correction information for the first position calculation means from the calculation result of the second position calculation means and the known arrangement position of the reference station. and a means for correcting the calculated position of the first position calculating means based on the correction information created by the correction information creating means.

In other words, if orbit information of GPS satellites cannot be obtained, GPS
The measured position of an object measured by satellite radio waves may drift by a certain amount in a certain direction from its true value. Therefore, the positions of a reference station whose assigned position is known and a plurality of moving objects are calculated based on the difference in reception time of radio waves transmitted from each GPS satellite. Since the reference station is known, the drift amount can be obtained as error information using this known position and the calculated position of the reference station. Based on this error information, the calculated positions of the plurality of moving objects are each corrected.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a mobile object monitoring device according to the present invention will be described with reference to the drawings.

In the embodiment, as shown in FIG.
This assumes that you are driving a car. A control office 20 serving as a base station for monitoring vehicles 10I to 107 is disposed at a predetermined position on the ground, as will be described later. Note that the assigned position (east longitude position, north latitude position) of the control office 20 serves as a reference point when performing correction processing to be described later. Three GPS satellites 31 to 33 are launched in the air (approximately 20,000 km above the earth), and these GPS satellites 31 to 33 transmit radio waves m1 to m, respectively, toward the ground. Vehicle 101
~103 has a receiving antenna 12 that can receive these radio waves m1~m.

Figure 2 shows vehicles 10□-10. On-board equipment 11 installed in each of the above, and ground equipment 2 installed in the control office 20.
1 conceptually shows the configuration of No. 1. The on-board device 11 is
Receiving antenna 12 and receiver 13 that receive radio waves m, to m3 from GPS satellites 31 to 33, and the received signals of receiver 13 are inputted to calculate the position of own vehicle 101 (i-"1 to n). Also, a central processing unit 14 that creates transmission data and image data, a transmitter 15 that transmits radio waves d to the ground device 21 based on the transmission data created by the central processing unit 14, an antenna 16, and the central processing unit 14. The display unit 17 displays the position of the own vehicle 10 based on the image data created by 22, receiver 23 and GPS satellites 31-3
3, a receiving antenna 24 for receiving the radio waves m, ~m, and a receiver 25; an input section 27 consisting of a keyboard or the like for manually inputting map information about the driving area 40; and the input results of the input section 27 and the receiver 23. .25 received signals are manually transmitted to multiple vehicles 10+ to 10. , a central processing unit 26 that performs data processing for displaying and printing the position of , and a central processing unit 2
A display unit 2 displays information on a CRT screen based on the processing results of step 6.
8 and a printer 29 that performs print processing based on the processing results of the central processing section 26.

The first embodiment will be described below with reference to the configuration shown in the figure and the flowcharts shown in FIGS. 6 to 8.

In the first embodiment, as shown in FIG.
When the radio waves m1 to m3 are received by the receiver 13 via the radio waves m1 to m3, the central processing unit 14 inputs the received signals at the time of receiving each of the radio waves m, to m (step 101), and receives the radio waves m1.
-m, and the positions of the GPS satellites 31 to 33, the two-dimensional position P1 of the own vehicle 10l (i-1 to n), that is, the east longitude position XlTl and the north latitude position Y■ are calculated.

It is assumed that the positions of the GPS satellites 31 to 33 are obtained based on orbit information. Also, i is n vehicles 10.
It is assumed that this is a vehicle number for specifying and identifying 10 degrees, and is assigned and given to each vehicle in advance (step 102). Next, the vehicle number i and the calculated position P1 of the own vehicle are modulated into a radio signal (step 103), and this radio signal is transmitted to the control office 20 as a radio wave d1 via the transmitter 15 and antenna 16. (Step 10
4). The processes of steps 101 to 104 are repeatedly executed for n vehicles 10. ~10fi positions P1~P,
Radio waves d1 to d0 indicating the following are transmitted toward the control office 20 at any time.

On the other hand, the ground equipment 21 of the control office 20 is connected to the vehicle 10. In order to measure the position from
The process of inputting via 7 is performed. That is, positional data such as the driving route 41 of the driving area 40 is input. The central processing unit 26 determines the driving area 4 based on the input position data.
0 map is created (step 201). When the pre-processing is completed in this manner, radio waves d1 to d are transmitted from the on-board devices 11 of the vehicles 10□ to 101. It is determined whether or not the signal has been received by the receiver 23 (step 202).
If the determination result is YES, that is, the radio wave d is received by the receiver 23 via the antenna 22, demodulation processing is performed to extract the vehicle number 1 and the position P: of the vehicle 101 superimposed on the received radio wave d as received data. (Step 203). Next, the procedure moves to the vehicle position correction subroutine shown in FIG. 8 (step 204), and a process is performed to correct errors included in the read position data P1 (step 3).
01-303).

That is, if the orbit information of the GPS satellites 31 to 33 is inaccurate, the measured position of the object measured by radio waves transmitted from the GPS satellites 31 to 33 will drift by a certain amount in a certain direction from the true value. There is. This amount of drift is constant for all objects to be measured. The vehicle position correction subroutine corrects this amount of drift.

As shown in FIG. 8, when the radio waves m1-m3 are received by the receiver 25 via the receiving antenna 24 of the ground equipment 21, the central processing unit 26 receives the radio waves m, -m.

Manually analyze the received signal at each reception point (Step 3)
01), the reference point (
Location Q of control office 20) (east longitude position x, north latitude position y)
is calculated. In this case, the measured reference point position Q will deviate from the true position determined by precise surveying of the reference point in advance by the amount of the drift (step 302).

Next, step 20 is performed from the east longitude position Xl and north latitude position Y1 of the vehicle position P demodulated in step 203 above.
East longitude position X, north latitude position y of reference point position Q calculated in step 3
The control office 20, which is the reference point, is subtracted.
Relative position R+ (
X+X, Y'+V) are calculated. Here, the measured values x, , y have errors ε1 and ε due to the above drift.
, and the measured value X1y also includes similar errors ε1, ε, but the errors are canceled by the above subtraction process.

Since the true position of the control office 20, which is a reference point, is known through a predetermined precision survey, information on how far the vehicle 101 is from the control office 20 can be accurately obtained by determining the relative position R2. can be obtained (step 303). , the procedure returns to step 205, and the vehicle 10. is corrected in step 204. By comparing the position R1 of the vehicle 10. with the map of the driving area 40, the vehicle 10. located within the driving area 40 is displayed on the display screen 28a of the display unit 28 as shown in FIG. ~10. ．． are displayed respectively. At this time, the vehicles 101 to 10° are represented by different marks depending on the car number i, and the n vehicles are identified by these different marks. In addition, vehicle 10. When comparing the position R4 of the vehicle 10 with the map of the driving area 40, the vehicle 10. It is necessary that the coordinate system of the position of the vehicle 10. and the coordinate system of the map of the driving area 40 are unified. If the position of R1 is a relative coordinate system, then the map of the driving area 40 also needs to be expressed in a relative coordinate system with the reference point as the origin.

In addition, vehicle 10. The absolute position of the vehicle 101 may be determined by adding the reference point position (absolute coordinate system) determined by precision surveying to the relative position R2. In this case, driving area 4
It is necessary to represent the map of 0 in an absolute coordinate system.

In addition, vehicle 10. In addition to graphically displaying the position of as a mark on the screen 2ga, the screen 28a also displays the message ``Vehicle number i is currently at east longitude position OO1 north latitude position XX'' and indicates it numerically. You can. In addition, the location of the destination is superimposed on the radio wave d, and each vehicle transmits it to the ground station 21.
By transmitting the destination to the map on the screen 28a (
It is also possible to identify and display a mark indicating the destination for each vehicle. Such a display allows the control office 20 to accurately transmit dispatch information, etc. to each vehicle using a predetermined wireless means, and the efficiency of vehicle operation is greatly improved.

Further, a display similar to the display shown in FIG. 3 is also displayed on the screen of the display unit 17 of the on-vehicle device 11. In this case, a map of the driving area 40 is prepared in the on-vehicle device 11, and displayed by comparing this map with the own position data P1 obtained in step 103. This display allows the driver to easily navigate even in unfamiliar locations.

The processes of steps 201 to 205 are repeatedly executed, and the sequentially calculated vehicle 10. The position data is stored in a memory (not shown) for each car number i together with the reception time of the signal d1 in step 202. Then, at the end of the operation for a certain period of time or one day, the contents of the memory are read out, and the read position data is printed out over time for each vehicle (for each car number) by the printer 29. ,Output. FIG. 5 shows, for example, the result of printing out the position of vehicle 101 with car number 1 every 5 seconds based on the stored position data. By recording the position of the vehicle as a function of time in this manner, it is possible to know the running details (running speed, stopping time, etc.) of each vehicle 101 to 10° for a certain period of time or for one day. Also,
The printed results can be used as they are as tachograph paper and daily business reports for each vehicle 10 to 103. Further, the travel trajectory of each vehicle may be displayed on the map on the screen 28a based on the contents stored in the memory at any time (step 205).

The second example will be described below. In this second embodiment, the configurations of the on-board device and the ground device are slightly different from those of the on-board device F11 and the ground device 21 in the first embodiment.

Figure 4 shows vehicles 10□-10. , and the configuration of the ground equipment 21'' installed in the control office 20. A receiving antenna 12' for receiving radio waves mlxm3, a receiver 13', and a receiver 1
3' is input, and the own vehicle 101 (i-1
-n), and write the above calculation results on a portable storage medium 15, which is removably provided in a predetermined holder, specifically a floppy disk, an IC card, etc., and then write the calculation results. a central processing unit 14' that creates image data based on the central processing unit 14', and a display unit 17 that displays the own vehicle position based on the image data created by the central processing unit 14'.
It is composed of ゛. On the other hand, the ground equipment 21
An input unit 27 consisting of a receiving antenna 24' and a receiver 25' that receive radio waves m and -m3 from the S satellites 31 to 33, and a keyboard or the like to input map information about the driving area 40.
', the manual result of the input section 27', and the received signal of the receiver 25- are input, and the storage medium 15'', which has been removed from the holder of the on-vehicle device 11', is attached to a predetermined holder. a central processing unit 26' that performs data processing to read out the memory contents of ' and display and print the 10° positions of a plurality of vehicles; and a display unit that displays on a CRT screen based on the processing results of the central processing unit 26''. 28- and
The printer 29- performs print processing based on the processing results of the central processing section 26-.

The second embodiment will be described below with reference to the configuration shown in the figure and the flowcharts shown in FIGS. 9 to 11.

As shown in Figure 9, radio waves m are transmitted through the receiving antenna 12''.
1 to m, are received by the receiver 13-, the central processing unit 1
In step 4, the received signals are input at the time of receiving each of the radio waves m1 to m3 (step 401), and the own vehicle 10I (vehicle number i- 1 to n) two-dimensional position P l ,
That is, east longitude position X1 and north latitude position Y1 are calculated (step 402). Next, the calculated position P is sequentially stored in the storage medium 15' at predetermined time intervals using the current time as an address (step 403). Steps 401-40
The process of 3 is repeatedly executed, but eventually, when the operation for a certain period of time or the operation for one day ends, the storage medium 15 is
'' is removed from the holder, and the processing of steps 401 to 403 ends.

On the other hand, as shown in FIG. 10, when the radio waves m1 to m3 are received by the receiver 25'' via the receiving antenna 24' of the ground equipment 21', the central processing unit 26' receives each of the radio waves m and m3. Input the received signal at the point (step 501
), reception time difference of radio waves m, -m3 and GPS satellites 31 to 3
Location Q of the control office 20 which is the reference point based on the location of 3.
(East longitude position x1 north latitude position y) is calculated (Step 5
02). Next, the calculated position Q is sequentially stored in a predetermined memory using the current time as an address.

In other words, this memory may be a portable, removable diskette or the like similar to the storage medium 15-, or may be a memory that cannot be separated from the central processing unit 26' (step 503). ).

The processes of steps 501 to 503 are repeatedly executed, but when the operation for a certain period of time or one day ends, the storage process for the position Q over time ends, as in the case of the storage medium 15'.

On the other hand, in the ground equipment 21' of the control office 20, the vehicle 10
,~10. ．． In order to perform the monitoring process, preprocessing is performed to set a map of the driving area 40 in the same manner as step 201 in FIG. 7 (step 601). When the preprocessing is finished,
The operator removes the storage medium 15' from the holder of the on-board device 11 of the vehicle 10, - 10o, and attaches it to the holder of the ground device 11. As a result, the contents stored in the storage medium 15' are read out. For the other vehicles 10□, 103, the respective storage media 15- are similarly attached to the holders, so that the position data over time of the vehicles 10□, 103 is read out (step 602). Next, the first
In the same way as the vehicle position correction subroutine of the embodiment, calculation processing for correcting the drift of the vehicle position is performed. That is, the intermittent position data of the reference point position Q (east longitude position The position data (east longitude position XI % north latitude position Yl) read from ' is correlated at the same time. Then, at each associated time, a process is performed to subtract the east longitude position x1 and the north latitude position y of the reference point position Q from the east longitude position X2 and north latitude position Y+ of the vehicle position P, respectively. Vehicle 10 with car number i whose origin is 20. relative position R+(X+ x.

Y ly ) is calculated. This kind of processing is car number 1.2
．． 3 respectively. As a result, the error due to drift at each time is canceled (step 603). Next, the vehicle 10 calculated in step 603. The printer 29' prints and outputs the positions R1, . . . for each vehicle (for each car number) over time (see FIG. 5). The record of the position expressed as a function of time in this way remains unchanged for the vehicle 10. It can be used as a daily business report. Further, the contents of FIG. 5 are displayed on the display screen of the display section 28'. In this case, the map of the driving area 40 created in step 601 is compared with the position R0 of the vehicle 101 calculated in step 603, and each vehicle 101 is displayed on the display screen of the display unit 28'.
~10. The travel trajectory of is displayed (step 604).

Note that the display section 17' of the on-vehicle device 11 displays the current position of the own vehicle on a map, similar to the display section 17 of the first embodiment.

According to this second embodiment, a plurality of vehicles 10. ~10. Although it is not possible to monitor the movement status of the
Since there is no need to communicate using radio waves d between There will be advantages in terms of.

In the embodiment, the control office 20 is used as the reference point for correcting drift, but the reference point is not limited to this.
, the setting point of the reference point is arbitrary.

Furthermore, instead of just one control office 20, two or more may be provided.

In addition, in the embodiment, a computation for correcting the drift is performed, but it is also possible to omit this correction process as appropriate, especially if the measurement accuracy is not affected.

In addition, in the embodiment, the position of the reference point is calculated sequentially and the drift is corrected sequentially, but the position of the reference point is calculated once or at most several times during the operation time, and the calculated value It is also possible to carry out the correction calculation by making it representative.

In addition, in the first and second embodiments, a taxi is assumed as the vehicle, and the case where it is applied to the operation management of the taxi is explained, but the application is not limited to this, and it can be applied to buses, construction machinery,
It can also be applied to automatic guided vehicles, etc. Furthermore, the present invention is not limited to mobile bodies that move on land, but can also be applied to mobile bodies that move on the sea, such as ships.

In addition, although the example assumes a case where two-dimensional measurement is performed, the case is not limited to this, and three-dimensional measurement in which height is also measured simultaneously is assumed.
Implementations that perform dimensional measurements are also possible.

When performing three-dimensional measurement, a minimum of four GPS satellites are required, and this is suitable for mobile objects on land or at sea, especially when height changes are required as information. Of course, it can be applied to monitoring moving objects that move in the air, such as aircraft.

〔Effect of the invention〕

As explained above, according to the present invention, the positions of a plurality of moving objects are measured based on radio waves transmitted from GPS satellites,
The movement status of multiple moving objects is monitored based on the measurement results. Therefore, the accuracy of position measurement is improved compared to the conventional sign post method. It can also be applied over a wide area at low cost.

Furthermore, flexibility in changing the layout of the operating course is improved. Also, the reliability of the device is improved. Also, the hassle of maintenance is eliminated. Moreover, when the positions of a plurality of moving objects are recorded as a function of time, the recorded results can be used as is as a daily report of operation, saving the time and effort of writing daily reports and greatly reducing the burden on the operator.

In addition, errors may occur in measurement results if the orbit information of GPS satellites is inaccurate, but in this case we have solved this by performing a correction calculation to remove the error, which has the effect of allowing highly accurate measurements. can get.

Furthermore, in the case of a configuration in which a plurality of moving bodies are provided with storage media, communication equipment can be omitted, resulting in an effect of lowering costs.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the external appearance of an embodiment of the mobile object monitoring device according to the present invention, and FIG. 2 is a diagram showing the on-board equipment installed in the vehicle shown in FIG. 1 and the ground equipment installed at the control office. FIG. 3 is a block diagram showing the configuration of the first embodiment; FIG. 3 is a diagram showing the running area displayed on the display screen of the display unit shown in FIG. 2; FIG. 4 is a block diagram showing the configuration of the first embodiment. This is a block diagram showing the configuration of the on-board equipment installed in the vehicle shown in the figure and the ground equipment installed in the control office. Figures 6 to 8 are flowcharts showing the processing procedure of the first embodiment with the configuration shown in Figure 2;
11 are flowcharts showing the processing procedure of the second embodiment having the configuration shown in FIG. 4, and FIG. 12 is a side view used to explain a conventional mobile body monitoring device. 10, ~10. ...Vehicle, 11.11-...Onboard device, 15-...Storage medium, 20...Control office, 2
121'...ground equipment, 28.28-...display section,
2929'...Printer. Figure 7 Figure 9 Figure 10 Figure 12

Claims (5)

[Claims] (1) A mobile object monitoring device that monitors a plurality of mobile objects based on signals from at least three GPS satellites installed in the air, comprising at least one base station, and the plurality of mobile objects are equipped with the following: GPS radio wave receiving means that receives radio waves transmitted from each GPS satellite; and position calculation means that sequentially calculates the position of the moving body based on the reception time difference of the radio waves from each GPS satellite received by the GPS radio wave receiving means. and transmitting means for transmitting the calculation result of the position calculating means to the base station together with the identification code of the own vehicle. (2) The base station includes: mobile body position receiving means for receiving a transmission signal from the transmitting means of the mobile body; and displaying the current position of each of the mobile bodies based on the received signal of the mobile body position receiving means. A monitoring device for a moving body according to claim 1, further comprising a display means. (3) The base station includes a mobile body position receiving means for receiving a transmission signal from the transmitting means of the mobile body, and a position of each of the mobile bodies as a function of time based on the received signal of the mobile body position receiving means. 2. The mobile object monitoring device according to claim 1, further comprising means for recording as follows. (4) In a mobile object monitoring device that monitors a plurality of mobile objects based on signals from at least three GPS satellites installed in the air, the plurality of mobile objects receive radio waves transmitted from each of the GPS satellites. GPS radio wave receiving means for calculating the position of the mobile body based on the reception time difference of radio waves from each GPS satellite received by the GPS radio wave receiving means; and a removable storage medium for storing information as a function of time. (5) A mobile object monitoring device that monitors a plurality of mobile objects based on signals from at least three GPS satellites installed in the air, comprising a reference station whose location is known, and in which the plurality of mobile objects a first GPS radio wave receiving means that receives radio waves transmitted from each of the GPS satellites; and a position of the mobile object based on the difference in reception time of radio waves from each GPS satellite received by the first GPS radio wave receiving means. and a first position calculating means for sequentially calculating a position, and the reference station includes: a second GPS radio wave receiving means for receiving radio waves respectively transmitted from the GPS satellite; a second position calculation means for calculating the position of the reference station based on the reception time difference of radio waves from each GPS satellite; and correction information creation means for creating correction information for the first position calculation means, and the calculated position of the first position calculation means is corrected based on the correction information created by the correction information creation means. Mobile monitoring device.