JP2003230174A - Method for position detection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for detecting position capable of detecting the position of a person or a mobile agent by using mobile communication systems installed indoors and outdoors, in which precision of the position detection is improved. <P>SOLUTION: Three radio beacons are located in a zone within which communication with a base station can be established, and another radio beacon is located on the gravity center of the triangle. The level of the electric wave received from each radio beacon is detected by a detection device provided near a mobile station, and then the radio beacon from which the highest intensity electric wave is received and the beacon placed on the gravity center are specified as a first radio beacon and a second radio beacon, respectively. An area in which the electric wave from the first radio beacon is receivable, and another area in which the electric wave from the second radio beacon is receivable are specified as a first area and a second area, respectively. The crossover of the first and the second areas is specified as a third area, which is divided into a fourth and a fifth areas. Based on the magnitude relation of the levels of the electric waves received from the first and the second radio beacons, either the fourth or the fifth area is selected, and the position of the mobile station is detected based on the selected area. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detecting method for detecting the position of a moving body, a person or the like by using a mobile communication system having a service area such as indoors or outdoors.

[0002]

2. Description of the Related Art For example, in order to monitor the position of a person indoors in a building, a device described below has been conventionally used. That is, a wireless receiver is installed in each indoor room. In addition, a radio transmitter is mounted on each card carried by a person moving inside the building.

When the person carrying the card is present inside the room, the radio receiver installed in the room detects the radio waves transmitted from the card. The wireless receiver in each room is connected to a monitor control device such as a personal computer by wire. Therefore, the monitor control device can identify in which room the wireless receiver has detected the radio wave from the card. By the identification code included in the radio wave from the card,
A person is specified. That is, it is possible to constantly monitor in which room the person to be monitored exists.

[0004]

In the conventional position detecting system, a radio receiver for receiving radio waves from the card must be installed in every room. In addition, since it is necessary to install a large number of wires indoors in order to connect a large number of wireless receivers to the monitoring and control device, it is difficult to install the position detection system.

Further, in the conventional position detection system, although it is possible to detect that the person to be detected is in a specific room, it is not possible to identify the position in the room. Furthermore, the person to be detected cannot know the position of himself. The present invention provides a position detection method capable of detecting the position of a person or a moving body by using a mobile communication system installed indoors or outdoors, and an object thereof is to improve position detection accuracy.

[0006]

According to a first aspect of the present invention, there is provided a position detecting method which utilizes four radio beacons each of which emits a predetermined radio signal, and three of the radio beacons are capable of communicating with a mobile station. The mobile stations are arranged at positions distant from each other within the communicable zone of the base station, and another radio beacon is arranged at a center of gravity of a triangle having three apexes of the respective installation locations of the three radio beacons. Detecting the reception level of each of the radio waves from the four radio signs by using a sign signal detection device arranged near the radio sign, and detecting the detected reception among the three radio signs arranged at the apex of the triangle. Identifying the first radio beacon with the highest level, of the four radio beacons,
The second radio beacon located at the center of gravity of the triangle is identified, the first area indicating the range in which the radio wave from the first radio beacon is received under a predetermined condition is identified, and the second radio beacon is identified. The second area indicating the range in which the radio wave from the wireless sign is received under a predetermined condition is identified, and the overlapping portion of the first area and the second area is identified as the third area. The two areas obtained by dividing the area are identified as a fourth area and a fifth area, and the reception level of the radio wave from the first radio sign and the radio wave from the second radio sign are identified. Either the fourth area or the fifth area is selected according to the magnitude relationship with the reception level, and the position of the mobile station is determined based on the selected fourth area or the fifth area. It is characterized by detecting.

In this method, the area in which the mobile station exists is
It can be gradually identified by a relatively simple process. Further, the position can be detected with high accuracy. According to a second aspect of the present invention, in the position detecting method according to the first aspect, when the third area is divided into the fourth area and the fifth area, the contour line of the first area and the second area are divided. The third region is divided into two with a line segment passing through two intersections with the contour line as a boundary.

According to a third aspect of the present invention, in the position detecting method according to the first aspect, the radio signal is intermittently transmitted from the radio sign, and the identification code of the radio sign is included in the radio signal. To do. The same radio frequency can be used for multiple radio beacons. Therefore, the configuration of the sign signal detection device can be simplified. The plurality of radio signs are distinguished from each other by the identification code. In addition, since intermittent transmission / reception is performed, it is very effective for power saving of the transmitter and the receiver.

According to a fourth aspect of the present invention, in the position detecting method according to the first aspect, each of the wireless beacons alternately uses a plurality of transmitting antennas arranged at positions distant from each other to transmit a wireless signal. The sign signal detection device alternately uses a plurality of receiving antennas arranged at positions distant from each other, and detects a radio wave from the wireless sign.

Since spatial diversity is performed for both the transmitting antenna and the receiving antenna, the reliability of the detected reception level is increased. That is, the measurement error due to fading is reduced. Multiple antennas are used in a time division manner. According to a fifth aspect of the present invention, in the position detecting method according to the first aspect, a plurality of reception levels detected for different radio signals from a plurality of radio signs at different points in time with respect to the same radio sign. It is characterized in that the values obtained by weighting and averaging the values of are identified.

For example, the reception level is sampled at a constant time period, and the latest sampled reception level value and the reception level value sampled before a predetermined time are weighted under predetermined conditions. And obtain the final reception level. This improves the reliability of the reception level. That is, the reception level measurement error in the system can be made extremely small.

According to a sixth aspect of the present invention, in the position detecting method according to the first aspect, when identifying the magnitude relation of the reception levels of the radio waves from a plurality of radio beacons, a plurality of comparisons of the reception levels detected at different times are performed. When a plurality of types of comparison results are obtained by performing the operation once, the comparison result having the maximum number of times of obtaining the same comparison result is finally adopted.

For example, the position detection is performed by receiving a large number of radio waves from the position detection transmitter, judging the magnitude relation of the reception levels each time it is received, and adopting the judgment result that the judgment result is more than half of the number of reception times. Do. That is, the reception level determination error in the system can be made extremely small.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) The structure and operation of a position detection system for carrying out the present invention will be described with reference to FIGS.
Shown in.

FIG. 1 is a block diagram showing the basic structure of the main part of the position detection system. FIG. 2 is a block diagram showing control hierarchical divisions of the system of FIG. Figure 3
It is a top view which shows those arrangement | positioning and the positional relationship of a wireless zone when the number of the position detection transmitters used is three. Figure 4
[Fig. 6] is a plan view showing the positional relationship between the arrangement and wireless zones when the number of position detecting transmitters used is four. FIG. 5 is a block diagram showing the configuration of the position detection transmitter 501. FIG. 6 is a block diagram showing the configuration of the position detection receiver 600.

FIG. 7 is a block diagram showing the functional configuration of the notebook computer 102. FIG. 8 shows the client 3
It is a block diagram which shows the functional structure of 10. Figure 9
3 is a block diagram showing a configuration of a mobile station 101. FIG. Figure 10
FIG. 3 is a block diagram showing the configuration of base station 201. Figure 1
FIG. 1 is a block diagram showing control for allocation of mobile stations to base stations. FIG. 12 is a time chart showing an example of the transmission timing of the position detecting transmitter. FIG.
FIG. 6 is a time chart showing an example of transmission timing of a position detecting transmitter. FIG. 14 is a time chart showing the reception level detection timing of the position detection receiver.

FIG. 15 is a flow chart showing the contents of processing for correcting the level of the signal from the position detecting transmitter. FIG. 16 is a graph showing changes in the reception level before and after level correction. FIG. 17 is a flowchart showing the position detection process of the first embodiment. FIG.
FIG. 3 is a plan view showing the positions of three position detection transmitters and the position and area of a processing target. FIG. 19 is a plan view showing the positions of the three position detection transmitters and the position and area of the processing target.

FIG. 20 is a plan view showing the positions of the three position detecting transmitters and the position and area of the processing target. Figure 21
FIG. 4 is a plan view showing the positions of four position detection transmitters and the position and area of a processing target. FIG. 1 shows the configuration of a system for detecting the position of one room indoors. Referring to FIG. 1, transmitters 501, 502, 503 and 504 dedicated to transmission for transmitting a predetermined radio signal are provided.

The position detecting transmitters 501 to 504 are installed on the ceiling, walls, etc. of the room. Wireless zone 511,51
2, 513 and 514 are formed by position detecting transmitters 501, 502, 503 and 504, respectively. A base station 201 used for communication is installed on the ceiling in the room. The base station 201 forms a wireless zone 202. Position detection transmitter wireless zones 511, 51
2, 513 and 514 are all included in the wireless zone 202 of the base station 201.

In this example, the mobile station 101 capable of communicating with the base station 201 is placed indoors. Further, the mobile station 101 and the position detection receiver 600 are connected to the notebook computer 102 arranged indoors. The position detection receiver 600 is a reception-only device, and receives the radio waves transmitted from the position detection transmitters 501 to 504. The signals transmitted from the position detecting transmitters 501 to 504 include the identification code previously assigned to each position detecting transmitter and the position information of the xy coordinates of the installation point.

Further, the position detection receiver 600 receives the radio waves transmitted from the position detection transmitters 501 to 504 and measures the reception level of each radio wave. And
For each position detecting transmitter, the identification code, the reception level, and the position information of the installation point are output from the position detecting receiver 600 to the notebook computer 102. Laptop computer 1
Reference numeral 02 transmits the identification code of each position detecting transmitter, the reception level, and the position information of the installation point, which are input from the position detecting receiver 600, to the base station 201 via radio waves via the mobile station 101.

The base station 201 is connected to the line control station 300. Although only one base station 201 is shown in FIG. 1, many base stations are actually connected to the line control station 300.
It is connected to the. The line control station 300 performs control as shown in FIG. That is, the base station with which the mobile station 101 is communicating is identified, and the reception levels of the radio waves from the mobile station 101 detected by each base station are compared to determine which base station has the highest reception level. , The location of the mobile station 101 is registered.

The line control station 300 is connected to the database 320 and the telecommunication network 400 via the client computer 310. Laptop computer 102
Calculates the current position of the mobile station 101 based on the identification code of each position detection transmitter, the reception level, and the position information of the installation point input from the position detection receiver 600, and calculates the current position of the mobile station 101 together with the map. Display position.

Mobile station 1 detected by notebook computer 102
The position information of 01 is sent to the client computer 3 via the mobile station 101, the base station 201, and the line control station 300.
Transferred to 10. Client computer 310
The base station 20 based on the transferred position information of the mobile station 101.
It is registered in the database 320 together with the position information of 1.

When the notebook computer 102 does not perform the arithmetic processing relating to the position of the mobile station 101, the client computer 310 executes the arithmetic processing. That is, the client computer 310 calculates the current position of the mobile station 101 based on the identification code of each position detecting transmitter, the reception level, and the position information of the installation point transferred from the notebook computer 102.

When the client computer 310 calculates the position of the mobile station 101, the position information of the mobile station 101 detected by the client computer 310 is transferred to the mobile station 101 via the line control station 300 and the base station 201. Transferred to. Information on the detected position of the mobile station 101 is registered in the database 320.

A map and the position of the mobile station 101 are displayed on the client computer 310. The position detection result registered in the database 320 is stored in the database 3 by the client computer 310 as necessary.
It is possible to read and display by accessing 20. In this example, the control system of the position detection system is divided into layers as shown in FIG.

Referring to FIG. 2, the first control system 10 of Layer 1 is a layer for acquiring information, and measures the reception level with respect to the position detecting transmitter, detects the identification code, and transmits the transmitter position information. Perform acquisition. The second control system 20 of Layer 2 is a layer for information transfer and processing, and carries out position detection of mobile stations, transfer of detection information, and display of position information. The third control system 30 of Layer 3 is a layer for storing and managing information, and manages position detection information and tracks mobile station positions.

That is, the position detecting receiver 600 receives the identification code from the position detecting transmitters 501 to 504 and the xy coordinates of the installation position, measures the reception level, and detects the position with the notebook computer 102. To do. The information on the position detection result is transferred from the mobile station 101 to the client computer 310 via the base station 201. Further, the position data is stored in the database 320 and the position detection information is managed. The position of the mobile station 101 is tracked by updating the position detection information in the database 320.

In FIG. 3, three position detecting transmitters 510 are shown.
The arrangement | positioning of wireless zone ZA, ZB, and ZC at the time of detecting a position using A, 510B, and 510C is shown. A triangle is formed by connecting the arrangement points of the three position detection transmitters 510A, 510B, and 510C to each other.
When the planar shape of the room is a square, one station is arranged on the bisector of one side of the square, and the other two stations are arranged at positions where an equilateral triangle is formed.

When the room has a rectangular shape, one station is placed on the bisector of one side of the rectangle and the other two
The station is placed in a position where an isosceles triangle is formed. With the position detecting transmitters 510A, 510B and 510C,
Wireless zones ZA, ZB and ZC are formed, and these wireless zones cover the entire room. In general, if three equidistant wireless zones are regularly arranged by using three position detecting transmitters, a certain area can be covered without any gap.
When the room has a rectangular shape as shown in FIG. 3, position detection may be performed by arranging equilateral triangles.

In FIG. 4, four position detecting transmitters 510 are shown.
The arrangement | positioning of wireless zone ZA, ZB, ZC, and ZD at the time of detecting a position using A, 510B, 510C, and 510D is shown. Four position detecting transmitters 510A and 510
A quadrangle is formed by connecting the arrangement points of B, 510C, and 510D to each other. When the planar shape of the room is a square, four position detecting transmitters 510A, 51
0B, 510C and 510D are arranged in a square, and in the case of a rectangle, they are arranged in a rectangle.

Position detecting transmitters 510A, 510B, 5
Wireless zones ZA, ZB, Z by 10C and 510D
C and ZD are formed. With these wireless zones,
The room shall be covered. The configuration of the position detecting transmitter 501 is shown in FIG. Referring to FIG. 5, the transmitter 5 for position detection
01 is a storage unit 521, a modulation circuit 524, a high frequency circuit 525, a timing control circuit 526, an antenna switch 527, antennas 528 and 529, and a power supply unit 5.
Equipped with 30.

The storage unit 521 stores predetermined identification code data 522 of the position detecting transmitter 501 and position coordinate data 523 indicating the xy coordinates of the installation position of the position detecting transmitter 501. is there. Storage unit 52
The identification code data 522 and the position coordinate data 523 read from No. 1 are modulated by the modulation circuit 524, converted into a high frequency signal by the high frequency circuit 525, and the antenna switching unit 52
The signal is transmitted from the antenna 528 or 529 as a radio wave via 7.

The antennas 528 and 529 are spatially separated from each other by a fixed distance. Two antennas 52
By using 8,529, space diversity of the antenna is realized in transmission. The same information is transmitted first from antenna 528 and then from antenna 529. The switching of the antenna to be used is periodically executed by the timing control circuit 526.

In the position detecting receiver 600, the information having the highest reception level is selected. The power of the position detection transmitter 501 is supplied from the power supply unit 530. The power supply unit 530 supplies electric power from a commercial power supply or a built-in solar cell. The other position detecting transmitters 502, 503, and 504 have the same configuration as the storage unit 5.
The position detection transmitter 501 is the same as the position detection transmitter 501 except for the stored data 21.

The structure of the position detecting receiver 600 is shown in FIG. Referring to FIG. 6, the position detection receiver 600 includes
Antennas 621, 622, high frequency circuits 623, 624,
Reception level detection circuits 625, 626, demodulation circuit 627,
628, control unit 629 and interface circuit 6
Equipped with 30. The position detection receiver 600 includes a plurality of antennas 62 for performing space diversity reception.
1,622. Radio waves from the position detection transmitter 501 are received by the antennas 621 and 622, converted into low frequency signals by the high frequency circuits 623 and 624, and then demodulated by the demodulation circuit 6.
Demodulated at 27,628.

Therefore, the identification code and the position information sent from the position detecting transmitter 501 are demodulated by the demodulation circuits 627 and 628.
These signals, which are output from, are applied to the control unit 629.

The other output of the high frequency circuits 623 and 624 is input to the reception level detection circuits 625 and 626. Reception level detection circuits 625 and 626 measure the reception levels of the radio waves from the respective position detection transmitters 501, 502 and 503. The measured reception level is input to the control unit 629 as a digital signal. The control unit 629 contains a microcomputer.
The control unit 629 selects a signal having a higher reception level from the signal received by the antenna 621 and the signal received by the antenna 622, and the position detection transmitters 501 to 504 included in the selected signal. The identification code and position information of the above and the information of the detected reception level are output to the notebook computer 102 via the interface circuit 630.

As described above, the reception level measurement error is significantly reduced by applying the transmission diversity and the reception diversity (reference: Ryuji Habuka: Statistics of average reception power in land mobile communication using "2-branch selection diversity". Estimation error ”, Theological theory (B), 67-B, 2, pp.218-219
(Sho 59-02)). The configuration of the notebook computer 102 is similar to that of a general computer. The functional configuration of the notebook computer 102 for the position detection system is as shown in FIG.

In the position detecting section 151, the position detecting transmitters 501, 50 input from the position detecting receiver 600 are inputted.
2, 503 identification codes, position detecting transmitters 501, 50
The position of the mobile station 101 is detected based on the xy coordinates indicating the installation positions of 2, 503 and the reception level information. In addition, the position detection unit 151 includes the identification code of the position detection transmitters 501 to 504 input from the position detection receiver 600, the xy coordinates indicating the installation positions of the position detection transmitters 501 to 504, and the reception level. The information is transferred to the client computer 310 via the mobile station 101, the base station 201, and the line control station 300. The position information of the mobile station 101 detected by the position detection unit 151 is also transferred to the client computer 310.

The map data storage section 152 holds map information. The display unit 153 displays a map based on the map information stored in the map data storage unit 152 and the position of the mobile station 101 detected by the position detection unit 151, and the position of the mobile station 101 is displayed on the map. . The configuration of the client computer 310 is similar to that of a general computer. The functional configuration of the client computer 310 for the position detection system is as shown in FIG.

In FIG. 8, the position detecting section 351 is provided with a position detecting transmitter 5 output from the position detecting receiver 600.
01 to 504 identification codes, position detecting transmitters 501 to 5
The position of the mobile station 101 is detected based on the xy coordinates indicating the installation position of 04 and the reception level information. Mobile station 10
When the mobile station 101 itself has the function of detecting the position of No. 1, the position information of the mobile station 101 is also input to the position detection unit 351, and in that case, the position detection unit 3
51 omits the position detection and outputs the input position information as it is.

The database control unit 352 registers the position information of the mobile station 101 detected by the position detection unit 351 in the database 320. Also, the database control unit 352
Reads the information registered in the database 320 as needed. The display unit 354 reads the map data in the vicinity of the position from the map data storage unit 353 based on the position information of the mobile station 101 output from the position detection unit 351, and displays the map. In addition, the detected mobile station 10
The position of 1 is also displayed. Further, if necessary, the past position data registered in the database 320 is read out via the database control unit 352 and displayed.

As shown in FIG. 9, the mobile station 101 includes an antenna 111, a high frequency circuit 112, a modulation / demodulation circuit 113, a communication information processing circuit 114, a codec 115, and a speaker 1.
16, microphone 117, control unit 118, memory circuit 1
19 and an interface circuit 120. The notebook computer 102 is connected to the interface circuit 120.

For example, a signal transmitted from the base station 201 is received by the antenna 111, converted into a low frequency signal by the high frequency circuit 112, demodulated by the modulation / demodulation circuit 113, and decoded by the communication information processing circuit 114. Of the received signal of the mobile station 101, the voice information included in the communication channel is D / A converted by the codec 115 and output from the speaker 116 as an analog signal. In addition, the mobile station 10
Various data included in the control channel among the received signals of No. 1 are transmitted from the communication information processing circuit 114 to the control unit 118.
Entered in.

The control unit 118 is a device containing a microcomputer and executes various controls. The data input to the control unit 118 is stored in the storage circuit 11
9 and is read as needed. Microphone 11
The audio signal input from the A.
Communication information processing circuit 1 D-converted and converted into a digital signal
14 is applied. This digital signal is encoded as a signal of the communication channel, and the communication information processing circuit 114
Is output from. The signal output from the communication information processing circuit 114 is modulated by the modulation / demodulation circuit 113, and the high frequency circuit 112.
Is converted into a high frequency signal and transmitted as a radio wave from the antenna 111. The control channel of the signal to be transmitted includes data (for example, mobile station identification code) output from the control unit 118.

As shown in FIG. 10, the base station 201 includes
Antenna 211, high frequency circuit 212, modulation / demodulation circuit 21
3, a communication information processing circuit 214, a codec 215, a reception level detection circuit 216, a control unit 217, and a storage circuit 218 are provided. For example, a signal transmitted from the mobile station 101 is received by the antenna 211, and the high frequency circuit 2
The signal is converted into a low frequency signal in 12, demodulated in the modulation / demodulation circuit 213, and decoded in the communication information processing circuit 214.

Among the reception signals of the base station 210, the voice information included in the communication channel is D / D by the codec 215.
It is A-converted and output as an analog signal from a speaker (not shown). Also, of the signals received by the base station 210, various data included in the control channel is input from the communication information processing circuit 214 to the control unit 217. Further, one output of the high frequency circuit 212 is input to the reception level detection circuit 216. Reception level detection circuit 216
Outputs the output level of the high frequency circuit 212, that is, the reception level proportional to the intensity of the received radio wave, to the control unit 217 as a digital signal. Reception level detection circuit 216
The reception level detected by is a component of either the control channel or the communication channel of the signal.

The control unit 217 is a device containing a microcomputer and executes various controls. The data input to the control unit 217 is stored in the storage circuit 21.
8 and is read as needed. When the reception level detection circuit 216 measures the reception level, at the same time, the mobile station identification code included in the control channel of the received signal is detected by the control unit 217. The reception level and the mobile station identification code corresponding thereto are stored in the storage circuit 218 as a pair of data.

Position detecting transmitter (501 to 504 in FIG. 1)
FIG. 12 shows an example of the transmission timing of (corresponding to). In this example, as shown in FIG. 12, burst signals are intermittently transmitted from the transmitters A, B, and C at regular time intervals T. That is, a plurality of position detecting transmitters 501 to 504
The burst signals from are transmitted with a time difference so that they do not overlap.

However, a plurality of position detecting transmitters 501 to 5
Since the burst signals output from 04 are not synchronized with each other, actually, a plurality of burst signals may overlap and interfere with each other. Therefore, in order to identify the presence or absence of interference, each of the position detection transmitters 501 to 504 includes a unique word in the signal transmitted by each of them. Position detection receiver 60
If the unique word cannot be detected at 0,
Consider that interference is occurring and ignore the signal.

Position detecting transmitter (501 to 504 in FIG. 1)
FIG. 13 shows the structure of the burst signal (corresponding to the above). Figure 1
3 (a) shows the transmitters 501 to 50 for position detection in the notebook computer 102 or the client computer 310.
4 does not have the xy coordinate data of 4, and the transmitter identification code for position detection and the transmitter installation point x for position detection
Send coordinate and y-coordinate information. In the case of transmission diversity, the same position detection transmitter identification code and position detection transmitter installation point x-coordinate and y-coordinate information are used for the antenna 1 and the antenna 2 (corresponding to 528 and 529 in FIG. 5). To send.

When the notebook computer 102 or the client computer 310 holds the xy coordinate data of the position detecting transmitter, only the position detecting transmitter identification code is stored as shown in FIG. It transmits using the antenna 1 and the antenna 2. In order to reduce the influence of level change due to fading of received radio waves, it is desirable to average the received levels before identifying the received levels. FIG. 14 shows a method of obtaining the average reception level of the radio waves transmitted from the position detecting transmitter.

In this example, a plurality of burst signals obtained by sampling at each time T are (1),
The average reception level is obtained by averaging either (2) or (3). (1) of FIG. 14 is a simple average formula.
(2) of FIG. 14 is an equation for weighting and averaging using the difference between the specific reception level and the reception level at the previous timing. Further, (3) in FIG. 14 is an equation for weighting and averaging by the squared value of the difference between the specific reception level and the reception level at the previous timing.

Generally, in the reception level measurement under fading, the reception level measurement error increases as the fading frequency decreases (reference: Ryuji Habuka: "Statistical average reception power in land mobile communication using two-branch selection diversity"). Estimated error ”, Theological theory (B), 67-B,
2, pp.218-219 (Showa 59-02)).

Therefore, the weighting process reduces the number of received level processed data when the communication terminal is in a nearly stationary state (E (i) -E (i-1) 0). Since the fading speed is high during movement, the level detection accuracy in position detection can be improved by averaging a large amount of data with few measurement errors. By the way, even if the transmission outputs of the plurality of position detecting transmitters 501 to 504 are the same, the position detecting transmitters 501 to 5 are caused by the directional characteristics of the antennas.
The reception level detected at reception points having the same distance from 04 may differ for each position detection transmitter.

Therefore, in this example, before the position detection is performed, the level correction is performed in advance by the procedure as shown in FIG. In this process, in the arrangement state of the plurality of position detecting transmitters as shown in FIGS. 3 and 4, at the points having the same distance from each of the position detecting transmitters 501 to 504 (triangular center of gravity or quadrangle), Level correction is performed so that the reception levels become equal.

In the first step S11 of FIG. 15, a plurality of adjacent position detecting transmitters 501 to 504 are grouped, and a plurality of position detecting transmitters 501 to 504 of the group are grouped.
The center of gravity of the polygon consisting of 504 is calculated. Step S
At 12, the reception level of each of the radio waves from the position detection transmitters 501 to 504 is measured at the obtained center-of-gravity position. E01, E02, E03, ...
・ E0n. When this measurement is carried out, it is manually placed by the human body at the position of the center of gravity determined by the position detection receiver 600.

In step S13, the maximum reception level Emax among the reception levels for each position detecting transmitter,
Reception levels E01, E02, E for each position detection transmitter
The differences E1d, E2d, ..., End from 03, ..., E0n are calculated.

In step S14, the measured reception levels Ec1, Ec2, ..., Ecn are added to the reception level differences E1d, E2.
d, ..., End are added. FIG. 16 shows an example of the reception level corrected by the level correction of FIG. 15 and the reception level before correction. As shown in FIG. 16, the reception level for each position detection transmitter varies depending on the distance between the position detection transmitters.

In the characteristics before correction, the curve of the reception level for the position detecting transmitter 1 and the position detecting transmitter 2
The crossing point of the curve of the reception level with respect to is about 25 m between the transmitters. Therefore, when the reception level is detected in the vicinity of 17 m between the position detecting transmitter 1 and the position detecting transmitter 2, although the distance from the two position detecting transmitters to the detected position is the same, There is a difference in reception level.

In the corrected characteristic, the point where the curve of the reception level for the first transmitter for position detection and the curve of the reception level for the second transmitter for position detection intersect is the distance between transmitters. It is around 17m. Therefore, 1
If the reception level is detected near 17 m between the 2nd position detecting transmitter and the 2nd position detecting transmitter, 2
There is no difference in the reception level between the two position detection transmitters.

FIG. 17 shows the contents of the position detection processing when the number of position detection transmitters used is three. This process
It is executed by the position detection unit 151 of the notebook computer 102 and the position detection unit 351 of the client computer 310. In the first step S21, the level correction shown in FIG. 15 is performed. In the next step S22, the reception level E1 is measured and the identification code is detected for the first position detecting transmitter. Similarly, in step S23, for the second transmitter for position detection, the reception level E
The measurement of 2 and the detection of the identification code are performed. Step S24
Then, the reception level E3 is measured and the identification code is detected for the third position detecting transmitter.

In steps S22, S23 and S24, the detected reception level is added to step S13 in FIG.
Add the level differences (E1d, E2d, ...)
Correct the reception level. In the next step S25, the magnitude relation between the detected reception levels E1, E2, E3 is identified. In the subsequent steps S26 to S30, the area in which the mobile station 101 exists is specified. In step S31, the detected position of the mobile station 101 is displayed.

Details of the contents of steps S26 to S30 will be described below with reference to specific examples. Here, as shown in FIG. 18, points at which the position detecting transmitter 1, the position detecting transmitter 2, and the position detecting transmitter 3 are arranged are A, B, and C, respectively. The position coordinates of points A, B, and C are A (xa, ya), B, respectively.
Let (xb, yb) and C (xc, yc). Further, the wireless zones of radius r of the position detecting transmitter 1, the position detecting transmitter 2 and the position detecting transmitter 3 are respectively represented by circles C
1, C2 and C3.

In step S26 of FIG. 17, the radio zone of one position detecting transmitter having the highest reception level is selected as the region R1. In the example of FIG. 18, since the reception level for the position detecting transmitter 1 is the highest, the portion surrounded by the circle C1 is set as the region R1. In FIG. 18, the region R1 is hatched. At this stage, it is considered that the mobile station 101 exists in the region R1.

In step S27, the line segment (B) connecting the installation point (A) of the position detection transmitter 1 having the highest reception level and the installation point (B) of the position detection transmitter 2 having the second highest reception level ( The coordinates of intersections E and F of the bisector (AB) (the line segment orthogonal to the line segment AB) and the circle C1 are obtained.
In step S28, as shown in FIG. 19, the magnitude relationship between the reception level E1 for the position detection transmitter 1 and the reception level E2 for the position detection transmitter 2 (E1> E2).
From this, a region (R2) surrounded by the straight line EF connecting the points E and F and the arc EF of the circle C1 is obtained.

In FIG. 19, the region R2 is hatched. At this stage, it is assumed that the mobile station 101 exists in the region R2. Step S29
Then, the position detection transmitter 2 having the second highest reception level
2 of the straight line BC that connects the installation point (B) of No. 2 and the installation point (C) of the position detection transmitter 3 having the third highest reception level.
The coordinates of the intersection G of the equal line (the line segment orthogonal to the line segment BC) and the circle C1 are obtained. Furthermore, the bisector of line segment BC and line segment A
The coordinates of the intersection H with B are determined.

In step S30, as shown in FIG. 20, the line segment EH is determined from the magnitude relationship (E2> E3) between the reception level E2 for the position detecting transmitter 2 and the reception level E3 for the position detecting transmitter 3. , GH and arc E of circle C1
A region (R3) surrounded by G is obtained. In FIG. 20, the region R3 is hatched. When the number of position detecting transmitters to be used is 3, the area R shown in FIG.
3 is recognized as an area where the mobile station 101 exists. This region R3 is displayed as the position of the mobile station 101.

In the process of FIG. 17, in order to judge the reception level, the reception of the radio wave from the position detecting transmitter and the detection of the reception level are actually performed many times (2N + 1).
N: Natural number) Repeat. Then, every time the reception level is measured, the reception level (E1, E2, E
3) The size relationship is determined, and the determination result in which the number (L) of determination results is equal to or greater than half the number of receptions (L ≧ N + 1) is finally adopted. This can reduce the determination error.

Even when four position detecting transmitters are used, the area in which the mobile station 101 exists can be specified by the same processing as in FIG. When the fourth position detecting transmitter is installed at the coordinate D (xd, yd), the area R3
Can be further divided to limit the position detection range.

That is, after the area R3 is obtained in step S30 of FIG. 17, the coordinates of the intersections K and L of the bisector of the straight line CD and the circle C1 are obtained as shown in FIG. The reception level for the fourth position detecting transmitter 4 is E4. In the case of E1>E2>E3> E4, the range surrounded by the straight line KL, the straight line HL, the straight line EH, and the arc EK of the circle C1 is defined as the region R4.

(Second Embodiment) FIG. 22 shows the contents of the position detection processing of this embodiment, and FIG. 23 shows an example of the position of the processing target and the arrangement of the areas. This form corresponds to all the claims. The configuration is the same as that of the first embodiment except that the arrangement of the position detection transmitter and the position detection process are changed. In this form, the first area, the second area, the third area, the fourth area, and the fifth area of claim 1 are circles C1 and C1, respectively.
It is embodied as a circle C4, a region Ra, a region Rb, and a region Rc.

In this example, the position detecting transmitter is shown in FIG.
At coordinates A (xa, ya), B (xb, yb), C (x
c, yc) and D (xd, yd), respectively. In FIG. 23, the coordinates A (xa, ya), B (xb,
yb) and C (xc, yc) are located at the vertices of the triangle, and the coordinate D (xd, yd) is located at the center of gravity of the triangle.

Further, the wireless zones formed by the four position detecting transmitters are respectively circles C1, C2 and C3.
And C4, and the intersections of the circle C1 and the circle C4 are E and F. In step S41 of FIG. 22, the level correction shown in FIG. 15 is performed. In the next step S42, the reception level E1 is measured and the identification code is detected for the first position detecting transmitter.

Similarly, in step S43, the reception level E2 is measured and the identification code is detected for the second position detecting transmitter. In step S44, the reception level E3 is measured and the identification code is detected for the third position detecting transmitter. In step S45, the reception level E4 is measured and the identification code is detected for the fourth position-detecting transmitter.

In the next step S46, the magnitude relation between the detected reception levels E1, E2 and E3 is identified. In the subsequent steps S47 to S50, the area in which the mobile station 101 exists is specified. In step S51, the detected position of the mobile station 101 is displayed. Step S47-
For details of the contents of S50, referring to specific examples,
This will be described below.

In step S47, the area of the position detecting transmitter 1 having the highest reception level is selected based on the magnitude relation of the reception levels (E1>E2> E3). In the example of FIG. 23, since the position detecting transmitter having the highest reception level exists at the coordinate A (xa, ya), the region surrounded by the circle C1 having the radius r is selected. In step S48, the reception level E4 for the position detecting transmitter 4 arranged at the center of gravity of the triangle is compared with the maximum reception level E1. E
If 4> E1, the process proceeds to step S49, and if E4 ≦ E1, the process proceeds to step S50.

If E4> E1, step S49
Then, a region Rc surrounded by the straight line EF and the arc EF of the circle C4 is obtained. If E4 ≦ E1, in step S50,
A region Rb surrounded by the straight line EF and the arc EF of the circle C1 is obtained.

[0081]

According to the present invention, the area where the mobile station exists is
It can be gradually identified by a relatively simple process. Further, the position can be detected with high accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a main part of a position detection system.

FIG. 2 is a block diagram showing control hierarchical divisions of the system of FIG.

FIG. 3 is a plan view showing the positional relationship between the positions of the transmitters for position detection and the wireless zones when the number of transmitters used is three.

FIG. 4 is a plan view showing the positional relationship between the arrangement and wireless zones when the number of position detecting transmitters used is four.

5 is a block diagram showing a configuration of a position detection transmitter 501. FIG.

6 is a block diagram showing a configuration of a position detection receiver 600. FIG.

FIG. 7 is a block diagram showing a functional configuration of the notebook computer 102.

FIG. 8 is a block diagram showing a functional configuration of a client 310.

9 is a block diagram showing a configuration of a mobile station 101. FIG.

10 is a block diagram showing a configuration of a base station 201. FIG.

FIG. 11 is a block diagram showing control for allocation of mobile stations to base stations.

FIG. 12 is a time chart showing an example of transmission timing of a position detection transmitter.

FIG. 13 is a time chart showing an example of transmission timing of a position detecting transmitter.

FIG. 14 is a time chart showing the reception level detection timing of the position detection receiver.

FIG. 15 is a flowchart showing the contents of processing for correcting the level of the signal from the position detection transmitter.

FIG. 16 is a graph showing changes in reception level before and after level correction.

FIG. 17 is a flowchart showing a position detection process of the first embodiment.

FIG. 18 is a plan view showing the positions of three position detection transmitters and the position and area of a processing target.

FIG. 19 is a plan view showing the positions of three position detection transmitters and the position and area of a processing target.

FIG. 20 is a plan view showing the positions of three position detection transmitters and the position and area of a processing target.

FIG. 21 is a plan view showing the positions of four position detection transmitters and the position and area of a processing target.

FIG. 22 is a flowchart showing the contents of position detection processing in the second embodiment.

FIG. 23 is a plan view showing positions of four position detection transmitters and positions and regions of processing targets according to the second embodiment.

[Explanation of symbols]

10 First control system 20 Second control system 30 Third control system 101 mobile station 102 laptop 111 antenna 112 high frequency circuit 113 Modulation / demodulation circuit 114 Communication information processing circuit 115 codecs 116 speakers 117 Mike 118 control unit 119 Memory circuit 120 interface circuit 151 Position detector 152 map data storage unit 153 display 201 base station 202 wireless zone 211 antenna 212 high frequency circuit 213 Modulation and demodulation circuit 214 Communication information processing circuit 215 codec 216 Reception level detection circuit 217 Control unit 218 Memory circuit 300 line control station 310 client computer 320 database 351 Position detector 352 database control unit 353 map data storage unit 354 display 400 telecommunications network 501,502,503,504 Position detection transmitter 511, 512, 513, 514 wireless zone 521 storage unit 522 identification code data 523 Position coordinate data 524 Modulation circuit 525 high frequency circuit 526 Timing control circuit 527 Antenna switch 528,529 antenna 530 power supply unit 600 Position detection receiver 621,622 antenna 623, 624 high frequency circuit 625,626 Reception level detection circuit 627,628 demodulation circuit 629 control unit 630 interface circuit ZA, ZB, ZC, ZD wireless zone

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5K067 AA33 BB21 DD44 EE02 EE10                       EE14 EE24 FF03 GG11 JJ52                       JJ54

Claims (6)

[Claims] 1. Each of which emits a predetermined radio signal 4
One radio sign is used, three of the radio signs are arranged at positions distant from each other within a communication zone of a radio base station capable of communicating with a mobile station, and another radio sign of the three radio signs is placed. Each of the installation positions is arranged at the center of gravity of a triangle having three vertices, and the reception level of each of the radio waves from the four radio signs is detected by using a sign signal detection device arranged near the mobile station. And out of the three radio signs placed at the apex of the triangle,
The first radio beacon having the highest detected reception level is identified, and the second radio beacon located at the center of gravity of the triangle is identified from among the four radio beacons, and the first radio beacon is identified. Identifies a first area indicating a range in which a radio wave from is received under a predetermined condition, and identifies a second area indicating a range in which a radio wave from the second wireless beacon is received under a predetermined condition, A portion where the first region and the second region overlap is identified as a third region, and two regions obtained by dividing the third region are referred to as a fourth region.
And a fifth area, and the fourth area is determined according to the magnitude relationship between the reception level of the radio wave from the first radio sign and the reception level of the radio wave from the second radio sign. And a fifth area, and detects the position of the mobile station based on the selected fourth area or fifth area. 2. The position detecting method according to claim 1, wherein
When dividing the third region into the fourth region and the fifth region, a line segment passing through two intersections of the contour line of the first region and the contour line of the second region is used as a boundary. A position detecting method, characterized in that the third region is divided into two. 3. The position detection method according to claim 1, wherein
Intermittently transmitting a radio signal from the radio sign,
A position detecting method, wherein the wireless signal includes an identification code of the wireless sign. 4. The position detecting method according to claim 1, wherein
Each of the radio signs transmits a radio signal by alternately using a plurality of transmission antennas arranged at positions distant from each other, and the sign signal detection device has a plurality of reception antennas arranged at positions distant from each other. The position detecting method is characterized in that the radio waves from the wireless sign are detected by alternately using the. 5. The position detecting method according to claim 1, wherein
To identify the value obtained by weighting and averaging the values of multiple reception levels detected at different times for the same radio sign when identifying the magnitude relationship of the reception levels of radio waves from multiple radio signs. A position detection method characterized by: 6. The position detecting method according to claim 1, wherein
When identifying the magnitude relationship between the reception levels of radio waves from a plurality of radio signs, the reception levels detected at different times are compared multiple times, and when multiple types of comparison results are obtained, A position detecting method characterized in that the comparison result having the maximum number of times of obtaining the same comparison result is finally adopted.