JP3453547B2 - Wireless network positioning system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal station positioning system using a wireless network.

[0002]

2. Description of the Related Art Generally, a base station, a mobile terminal station wirelessly connected to the base station and having a positioning means such as GPS for positioning the own station, and a base station connected to the base station by a wired LAN, There is known a wireless network control system including this base station and a control station that totally controls the terminal station.

In this type, 1) one wireless channel can measure the positions of a plurality of terminal stations by the DGPS positioning method in real time. 2) A wide range of positioning is possible by combining wired and wireless networks. 3) The positioning position of each terminal station can be displayed in real time at the control station (or base station). 4) The terminal station can display its position in real time. 5) It has a feature that past movement data can be reproduced from the communication log output from the data communication device in the control station.

However, the conventional system is a system operation for the purpose of displaying the position of each terminal station on a display device in a control station (or base station) and monitoring each terminal station (moving body). Therefore, in the terminal station, only the position information of only the own station is displayed. On the other hand, for example,
There is a demand for knowing the trends of other terminal stations existing around the own station in order to avoid danger in a state where visual inspection is impossible.

In such a case, the conventional system does not have a function (peripheral vehicle monitoring function) for displaying position information of a terminal station (for example, a vehicle) existing in the vicinity of the terminal station.
There is a problem that it is not possible to meet the above demand.

[0006]

In order to realize the peripheral vehicle monitoring function in the above system, the latest information of each terminal station stored in the position information database installed in the control station (or base station) is used. It becomes possible by communicating (downloading) the position information from the control station to the terminal station via the base station using the downlink.

However, this method has the following problems.

First, depending on the number of operated terminal stations,
Real-time property is lost. This means that the position information increases in proportion to the number of terminal stations, and the time to download it increases. That is, if standardization is performed based on the polling cycle, the time for communicating information given per terminal station will be reduced. As a result, in order to communicate all information, a plurality of polling cycles are required, and there is a problem that a desired time becomes long. Therefore, there is a delay in the time until it is displayed at the terminal station, and the positional relationship between the terminal station itself and the surrounding vehicle group is not absolute time but relative time, and the larger the delay, the more the positional display relationship of each vehicle shifts. It means that the real time is not satisfied.

Second, the throughput based on the system operation form is reduced. This means that when the previous data transmission time is satisfied in one polling cycle (standardized polling cycle), for example, in the polling protocol, the packet length for data distribution to the terminal station by downloading in the information exchange area in the P phase is set. , Must be equal to or longer than the required data length. Therefore, when the number of terminal stations operated in the system is taken into consideration, the polling cycle becomes very long, resulting in a decrease in throughput.

As a method of alleviating these problems, a method of varying the packet length between the terminal station that needs the peripheral vehicle monitoring function and the terminal station that does not need the peripheral vehicle monitoring function can be considered.

However, in order to realize this, it is necessary to identify the terminal stations in advance, for example, to recognize the distinction of the packet data length in the information exchange area of the P phase, and to set the timers of the respective terminal stations related to each other. It is not efficient because it is necessary to clarify the time relation of, and it is necessary to add complicated processing to the program.

Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional technique and to provide a wireless network positioning system capable of realizing a peripheral vehicle monitoring function with a simple configuration.

[0013]

The invention according to claim 1 is
A base station, a movable terminal station that is wirelessly connected to the base station and has a positioning unit that measures the position of its own station, and a wired LAN that is connected to the base station and controls the base station and the terminal station. In a wireless network positioning system including a control station that dynamically controls, the position information of the other second terminal station is transmitted to the selected first terminal station, and the second terminal station is displayed on the display function of the first terminal station. a configuration for displaying the position, the
The position information of the second terminal station is the information of the above-mentioned control station or base station.
A database is installed in some places and the position of each terminal station
Store the location information and access the database
The first terminal station and the second terminal station
The location information of the
Calculate the distance between the terminal station and the above-mentioned second terminal station, and
Select the second terminal station from the highest to the preset number
To transmit only those location information from the base station to the first terminal station
It is characterized by having a configuration .

According to a second aspect of the present invention, in the first aspect, the means for transmitting the position information of the other second terminal station to the selected first terminal station is the base station and the first terminal station. In the wireless communication between and, a broadcast section is provided within a period of transmission from the base station, and the position information is transmitted to the first terminal station within the section. is there.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the described one, send the location information of the terminal station that is far away
It is characterized by lowering the rate .

The invention according to claim 4 is the invention according to claims 1 to 3.
In one of the above, the terminal station has
The positioning means for positioning the own station is GPS, DGPS or
Is a RTK GPS .

[0017]

[0018]

[0019]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example of construction of a wireless LAN based on a spread spectrum (SS) wireless communication system.
2 and 3, a mobile terminal station 5 (5A to 5D), and a control station 7 that comprehensively manages the terminal station 5 and the base stations 1, 2, and 3. The base stations 1, 2, 3 and the terminal station 5 within the communication area of the base stations 1, 2, 3 transmit and receive data by the SS communication method. In other words, these base stations form a wireless LAN with each terminal station within its communication area, and access the terminal stations by a polling procedure to exchange data. Therefore, it is necessary that the terminal station that constitutes the wireless LAN of a certain base station is registered in the base station. Also,
The base stations 1, 2, 3 and the control station 7 are connected to the wired LAN 1 and function as terminals of the wired LAN 1.

FIG. 2 is a block diagram showing an example of the configuration of the base stations 1, 2, and 3. The wired communication unit 21, the SS wireless communication unit 22,
It is composed of a memory unit 23 and a control unit 24.

The wired communication section 21 is a section for communicating with the wired LAN 1, and is represented by, for example, Ethernet. The SS wireless communication unit 22 is a unit that controls SS modulation / demodulation, the memory unit 23 is a unit that stores and relays data between the wired communication unit 21 and the SS wireless communication unit 22, and the control unit 24 is these three blocks. Is a part for controlling data transmission and relaying data according to a predetermined procedure (protocol).

FIG. 3 is a block diagram showing an example of the configuration of the terminal station 5, including the SS wireless communication section 42, the memory section 43, and the control section 4.
RS-232C as an external connection
The GPS positioning device 61 is connected using a serial system such as.

The SS wireless communication section 42 is a section that controls SS demodulation / modulation. As a matter of course, SS modulation and S between the wireless communication unit 22 of the base station and the SS wireless communication unit 42 of the terminal station
The S demodulation method must be the same. Memory unit 4
Reference numeral 3 is a portion for storing and relaying data of the SS wireless communication unit 42, and control unit 44 is a portion for controlling these two blocks and relaying data according to a predetermined protocol.

FIG. 4 is a block diagram showing a configuration example of the control station 7, which is composed of a wired network communication section 51, a memory section 53, and a control section 54. The wired network communication unit 51 is a unit that communicates with the wired LAN 1. The memory unit 53 is a unit that stores and relays the data of the wired network communication unit 51, and the control unit 54 is a unit that controls these two blocks and relays the data according to a predetermined protocol.

As shown in FIG. 1, the control station 7 connects the base stations 1, 2 and 3 to each other by a wired LAN on the same network, and the base stations 1, 2 and 3 and the wired LA are connected to each other.
By exchanging control packets on N, the management operation of each base station 1, 2, 3 and terminal station 5 is realized.

In the present embodiment, the selected terminal station (first terminal station) 5 has a function of displaying position information of a plurality of other terminal stations (second terminal stations) 5 existing in the vicinity thereof, a so-called function. It has a peripheral vehicle monitoring function.

As shown in FIG. 3, a GPS positioning device 61 is connected to each terminal station 5 as an external connection. The position information of each terminal station 5 is sent to the base station 1, 2 or 3 in real time through the GPS positioning device 61, and this position information is sent from the base station to the control station 7 via the wired LAN. Then, this position data is stored in the database of the control station (or base station) 7.

The control station (or base station) 7 identifies the first terminal station 5 (mobile unit A) requiring the peripheral vehicle monitoring function from the latest position information of each terminal station 5 stored in the database. Distance calculation is performed based on position information.

Assuming that there are 10 moving bodies around the moving body A as shown in FIG. 5, distance calculation between the 10 moving bodies and the moving body A is performed,
Based on each of the obtained distances d1 to d10, the position information of N terminal stations from the one closest to the moving body A is sorted, and the position information of the corresponding moving body as well as the information related to the moving body is sorted. To extract. Then, for example, a display device (not shown) such as a navigation device for a general-purpose automobile used in the moving body A displays position information of the N moving bodies (peripheral vehicle monitoring function). According to this
Since the own station can know the trend of other terminal stations existing in the vicinity thereof, for example, it is possible to sufficiently avoid the danger in a state in which visual observation is impossible.

In this embodiment, the number N of moving bodies to be sorted is N = 7, and moving bodies d8 to d10 having a long distance are not selected.

Here, the distance calculation and the calculation such as sorting are performed by the control station (or base station) 7 from this system operation mode, but the invention is not limited to this.
If it is connected to the wired LAN and the database can be accessed, it can be processed by another terminal.

Here, it does not matter about the operation of an application that installs such a terminal and operates a network system. It is important to be able to perform processing such as distance calculation. It should be noted that the above N units are the number of units that can be displayed as peripheral vehicles due to their screen size and display capability if the display device used in the terminal station is, for example, a general-purpose automobile navigation device. By limiting the number of terminals to N in this way, the data transmission time to the terminal station can be reduced.

Next, a communication system between the base station and the terminal station will be described.

In this embodiment, the polling method is adopted. In this polling method, since communication is performed under the control of the base station, a situation in which a plurality of terminal stations transmit at the same time cannot occur. This polling method is one of the well-known access methods in a wired network. Typically, a network management device sequentially calls a terminal device connected to the network at regular time intervals to determine whether data can be exchanged and whether the device is busy. It is a method of knowing whether or not it is necessary and performing a corresponding process.

FIG. 6 shows the operation phase. P phase is a phase for performing polling operation and leaving operation, C
The phase is a phase for performing a joining operation. In the P phase, the polling method is adopted as the access method, and in the C phase, the contention method by CSMA is adopted.

FIG. 7 is a concrete example of the polling procedure in the P phase, and FIGS. 8 and 9 are flowcharts thereof. Referring to FIG. 8, the base station starts the P phase using the declaration frame (S1). When the transmission of the P-phase start frame is processed (S2), the polling table (information table) of the base station is referred to (S).
3). Various information is stored in this polling table. When the connection of the terminal station is confirmed according to the polling table (S4), the inquiry frame is transmitted to the connected terminal station (S5). Wait until the response frame from the first terminal station is transmitted (S
6) If the response frame is received (S7), the process proceeds to the next table (terminal station) (S8), and if the next terminal station exists, S3 to S8 are repeated. If the response frame is not received within the predetermined time in S6, reception error processing is performed (S9).

If the next table (terminal station) does not exist in S8, the process proceeds to S10 shown in FIG. 9 and the polling table (information table) of the base station is referred to. When there is communication data to be transmitted to the first terminal station (S11), first, the instruction frame is transmitted to that terminal station (S12). Then, an information frame is transmitted and received (S13), and then the process proceeds to the next table (terminal station) (S14). If the next terminal station exists, S10 to S10.
Repeat S14. If the next terminal station does not exist, the P phase ends.

In the above communication mode, a broadcast section is provided in order to distribute common data to all terminal stations 5.

As shown in FIG. 7, this section is installed before declaring the start of the P phase and has a variety of section lengths. It is a fixed section or a variable section or a spare section having a required data length or more. Is set to include.

In the present embodiment, the broadcast section, that is, the section in which the control station (or the base station) can deliver to all the terminal stations is used for the terminal stations requiring the above-mentioned peripheral vehicle monitoring function. , The above-mentioned position information and the terminal station information related thereto are downloaded. As a result, the throughput can be reduced and efficient system operation can be performed as compared with the method of using the polling period that normally controls the uploading / downloading of data.

It should be noted that this is just an example, and it is possible to download the program in a section in which the start of the P phase is declared in the figure, for example. Further, it is desirable to reduce the position information transmission rate of the terminal station 5 that is far away.

In this embodiment, the terminal station has a peripheral vehicle monitoring function and can know the trend of other terminal stations existing in the vicinity of the terminal station. Evasion can be done. In addition, by proposing a method of selecting a terminal station that provides a peripheral vehicle monitoring function and a terminal station with a high degree of importance (terminal station) for that terminal station, the amount of data transmission to the terminal station is minimized and This makes it possible to realize a peripheral vehicle monitoring function with high real-time characteristics. By transmitting not only the position information of the peripheral terminal station but also the vehicle information at the same time, it is possible to obtain an effect such as more effective display of the peripheral vehicle at the terminal station.

[0044]

According to the present invention, since the terminal station has a peripheral vehicle monitoring function and can know the trend of other terminal stations existing in the vicinity of the terminal station, it is possible to avoid danger in a state where visual inspection is impossible. It can be carried out.

[Brief description of drawings]

FIG. 1 shows a wireless network positioning system.

FIG. 2 is a block diagram of a base station.

FIG. 3 is a block diagram of a terminal station.

FIG. 4 is a block diagram of a control station.

FIG. 5 is a diagram illustrating calculation of a distance between a moving body A and a moving body.

FIG. 6 is a block diagram of an operation phase.

FIG. 7 is a diagram showing a P-phase communication procedure.

FIG. 8 is a flowchart showing a P-phase communication procedure.

FIG. 9 is a flowchart showing a P-phase communication procedure.

[Explanation of symbols]

1, 2, 3 base stations 5 (5A-5D) Terminal station 7 control station

Front page continuation (72) Inventor Yoshitaka Uchida 5-35-2 Hakusan, Bunkyo-ku, Tokyo Clarion Co., Ltd. (72) Inventor Koichi Kato 5-35-2 Shirayama, Bunkyo-ku, Tokyo Clarion Co., Ltd. (72) Inventor Toshikazu Suwa 5 35-2 Hakusan, Bunkyo-ku, Tokyo Clarion Co., Ltd. (56) References JP-A-11-201762 (JP, A) JP-A-11-251992 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04B ^7/ 24-7/26 H04Q ⁷ /00-7/38

Claims (4)

(57) [Claims] 1. A base station, a mobile terminal station that is wirelessly connected to the base station and has a positioning unit that measures the position of the own station, and a wired LAN that is connected to the base station. In a wireless network positioning system including a terminal station and a control station that controls the terminal station as a whole, position information of other second terminal stations is transmitted to the selected first terminal station, and a display function of the first terminal station is provided. a configuration for displaying the position of the second terminal station, the location information of the second terminal station, the control station or the base station
Install a database in one of the
Location information is stored and the database is accessed.
Scan to a configuration that acquires the position information of the above data of the first terminal station and said second terminal station
Acquired from the database, the first terminal station and the second terminal station
Distance is calculated, and the distance is
Select the second terminal station up to the set number and
The wireless network positioning system is characterized in that only the base station transmits to the first terminal station . 2. The means for transmitting the position information of the other second terminal station to the selected first terminal station is transmitted from the base station in wireless communication between the base station and the first terminal station. The wireless network positioning system according to claim 1, wherein a broadcast section is provided within a period, and the position information is transmitted to the first terminal station within the section. 3. A position information transmission rate of a terminal station having a long distance.
The wireless network positioning system according to claim 1 or 2, wherein 4. The position of the own station of the terminal station is measured.
The positioning means is GPS, DGPS or RTKGPS
The method according to any one of claims 1 to 3, characterized in that
Of wireless network positioning system.