JP2012007971A - Current location grasping method, current location grasping system, current location grasping program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To grasp a portable wireless terminal user's current location within a measurement area.SOLUTION: A location grasping device 20, based on data wave intensity table data prepared in advance, calculates an estimated distance to access points 101-118 in fixed-point observation points. The location grasping device 20, based on a correct answer data table prepared in advance, recalculates the estimated distance and determines in advance a combination of three access points which shows a threshold value or less in distance calculation errors. If the error between radio wave intensity of access points capable of receiving and the data of the radio intensity table does not show a threshold value or less, a portable wireless terminal 30, in accordance with the combination, selects a combination of plural access points capable of receiving and determines a current location by estimating a distance from each selected access point by radio wave intensity.

Description

  The present invention relates to a technique for grasping the current position of a user from the radio wave intensity of a portable wireless terminal with respect to an access point of a communication means such as a wireless LAN installed in a measurement area.

  Conventionally, as a technique for grasping the current position, (1) a method of acquiring position information of a mobile terminal using GPS information, or (2) a location where a user's mobile terminal is located using a mobile communication system. (3) Establish a wireless link with the wireless LAN terminal in the cover area, and check whether the user of the terminal that established the wireless link is a valid user A technique is known that collects information that the user is in the cover area, notifies the server, and obtains the current position if the user belongs to the area. An example of this current position grasping technique is described in Patent Document 1.

JP 2004-328309 A

  However, when GPS is used to acquire the location information of a portable wireless terminal, the GPS location information has an error of several tens of meters to several hundred meters, and there are many cases where radio waves do not reach indoors. The technology was not suitable for use. In addition, even when using a mobile communication system, it is not a method to know which display shelf in the store is in front of the mobile wireless terminal even though it is known that it belongs to the cover area. It was.

  Furthermore, in a technology for grasping the current position of a portable wireless terminal of a user who is communicating with an access point such as a wireless LAN used in an indoor mobile communication system, the access point is generally Since one area has jurisdiction over one area, access points are often located apart from each other. By searching for the closest access point or finding the access point with the strongest signal strength, It was only understood that he was in the jurisdiction area. For this reason, it is difficult to grasp the position when there are a plurality of access points with high radio field strength.

  For example, when the distance to multiple access points, such as in front of a display shelf in a store, is close, the radio wave intensity from multiple close access points is high, so determine the closest access point There was a problem that the accurate position could not be grasped.

  The present invention has been made to solve the above-described problems of the prior art, and accurately determines the current position of a user having a portable wireless terminal in a measurement area in which a plurality of access points are installed at a close range. It is a solution issue to grasp.

  Therefore, the present invention can grasp the user's position with high accuracy by installing an access point of a new communication system (such as a wireless LAN) in the measurement area for each measurement object, that is, the object to be measured as the current position, and can detect a close distance. Even when radio waves from a plurality of access points installed in the network exceed the reception intensity maximum value and the position cannot be specified only by the access point, it is estimated which object is located near.

  That is, (1) the position of each measurement object in the measurement area, the position of each access point, a map in which a plurality of fixed point observation positions determined in advance in the measurement area are recorded, and each access point for each fixed point observation position A first table that records the distance, a second table that records the radio field intensity according to the angle and distance at each access point, and a third table that records the radio field intensity of each access point at each fixed point observation position And (2) calculating an estimated distance from the radio wave intensity to the fixed point observation position for each access point based on the recorded data of the second table and the third table, and calculating the estimated distance and the recorded data of the first table. A process for predetermining a combination of a plurality of access points whose errors are less than or equal to a threshold; If the error between the second table and the recorded data of at least the third table of the second table and the third table is not less than the threshold value, a combination of a plurality of access points that can be received is selected according to the combination. A process for obtaining the current position by estimating the distance from each access point from the radio wave intensity is performed.

  According to the present invention, even when the distance between the mobile wireless terminal and the plurality of access points is a short distance, and the received radio waves from the plurality of access points cannot determine the closest access point due to high intensity, The current position can be estimated using partial data of the access point.

  Preferably, (1) a combination of three access points whose error between the estimated distance and the recorded data of the first table is not more than a threshold value is stored in the storage means, and (2) the radio waves of the access points that can be received by the portable wireless terminal If the difference between the intensity and the recorded data of at least the third table of the second table and the third table is not less than the threshold, a combination of access points is acquired from the storage means, and a plurality of accesses that can be received according to the combination 3 access points are selected from the points, and (3) a plurality of estimated position candidates are obtained based on the position of each selected access point and the estimated distance from each access point, and the center of gravity position of the estimated position candidate group is determined. Estimated current position.

  As a result, even if the radio wave condition is unstable and some noise is mixed in the measurement data, or the data is missing, the current position can be By obtaining an estimation candidate and estimating the position of the center of gravity of the estimation candidate as the current position, the accuracy of position estimation can be improved.

  At this time, if an estimated position candidate that is more than a threshold value away from the center of gravity of the estimated position candidate group is removed and the center of gravity of the estimated position candidate group after the removal is estimated as the current position, a more reliable and highly accurate estimated position Can be requested.

  If the error between the radio wave intensity of the access point that can be received by the portable radio terminal and the recorded data of at least the third table of the second table and the third table is equal to or less than the threshold value, the fixed point observation position of the radio wave intensity is determined. It can also be estimated as the current position. As a result, if radio wave intensities at a large number of fixed-point observation positions are prepared in advance, the current position can be easily estimated with high accuracy.

  ADVANTAGE OF THE INVENTION According to this invention, the present position of the user with a portable wireless terminal can be correctly grasped | ascertained within the measurement area where the some access point was installed in the short distance.

The utilization image figure of the position grasping system concerning the embodiment of the present invention. The structural example figure of the position grasping device. The structural example figure of the portable wireless terminal. The flow chart of the calibration process. An image of the store map. The image of the radio wave distribution. The flow chart of the measurement process.

  Hereinafter, a current position grasping system according to an embodiment of the present invention will be described. Here, as an example, description will be made based on an example in which a supermarket store is a measurement area and a plurality of wireless LAN access points are installed at a short distance for each display shelf in the store.

  Access points are installed to identify display shelves in the store. The position / ID of each display shelf, the position / ID of each access point, and the fixed point observation positions for the number of current positions set in the passage between the display shelves Create a recorded store map in advance. Further, the radio wave intensity pattern of each access point measured at the fixed point observation position is measured in advance with a portable wireless terminal, and the measurement result is recorded in an array table. Calibration is performed so that the radio wave intensity and the distance to the access point can be calculated based on the recorded data, and the radio wave intensity pattern and the distance to each access point are stored in advance. At this time, a combination of three access points that can be measured correctly for each fixed point observation position is obtained.

  At the time of measuring the current position, the radio field intensity from each access point of the portable wireless terminal is recorded, and the reception intensity of each access point is recorded in an array table having all the access points as elements. The sequence table recorded here is compared with the sequence table in which the radio field intensity of the fixed point observation is recorded in advance, and if there is a fixed point observation position whose comparison result is within the threshold, it is estimated as the current position. On the other hand, if there is no fixed point observation position within the threshold, the distance to each access point is calculated using the three radio wave intensity values prepared at the time of calibration, and all estimated position candidates that have calculated the distance to the access point are obtained. Classify into two classes. Here, the distance within the threshold from the center position of the estimated position candidate set is set as the main class, and a process of removing one estimated candidate farthest from the center position by the threshold or more is performed. This process is repeated until there are no estimated position candidates that are more than the threshold, and the center positions of all remaining estimated position candidates are obtained, and the position is estimated as the current position.

  Then, the estimated current position and the ID of the display shelf closest to the estimated current position are stored as data and displayed on the portable wireless terminal. This work provides an advantage that the current position grasping accuracy can be increased.

≪System configuration example≫
A configuration example of the system will be described with reference to FIGS. As shown in FIG. 1, the system 1 uses a position grasping device 20 and a portable wireless terminal 30 as a combination. Here, the portable wireless terminal 30 is connected to the Internet via the wireless LAN access points 101 to 118, and can transmit and receive data to and from the position grasping device 20 via the Internet. Each of the access points 101 to 118 is installed for each display shelf.

  The position grasping device 20 mainly determines the radio wave intensity pattern of the wireless LAN at each of the access points 101 to 118 in advance and the distance from the fixed point observation position previously determined in the path between the display shelves to each of the access points 101 to 118. Calibration for calculation is performed, and the distance between the radio wave intensity pattern and each access point is accumulated in advance. Specifically, the position grasping device 20 is configured by a server on the Internet, and includes hardware resources of a computer, such as a CPU, a memory (RAM), a hard disk drive device, a communication device, and the like. As a result of the cooperation between the hardware resource and the software resource (OS, application, etc.), as shown in FIG. 2, the position determination device 20 has a relationship table creation unit 21, a distance measurement unit 22, and a radio wave intensity pattern storage unit 23. The data storage unit 24, the communication unit 25, and the control unit 26 are mounted.

  That is, the communication unit 25 is realized by a communication device, and performs data transmission / reception with the portable wireless terminal 30. Further, it is assumed that the radio wave intensity pattern storage unit 23 and the data storage unit 24 are constructed in storage storage means such as a memory (RAM) or a hard disk drive device. In this data storage unit 24, it is assumed that the radio wave intensity of each of the access points 101 to 118 measured by the portable wireless terminal 30 is stored as needed. The control unit 26 controls the operations of the units 21 to 25.

  The relationship table creation unit 21 creates a store map that records the positions and IDs of the display shelves and the access points 101 to 118 in the store, the passages between the display shelves and the fixed point observation positions, and the relationship table. Each is stored in the radio wave intensity pattern storage unit 23. This relationship table includes a radio wave intensity list (array table) in which radio field intensity patterns of access points for each fixed point observation position are recorded, and a table in which distances to the respective access points 101 to 118 for each fixed point observation position are recorded, that is, correct answers. It is composed of a data list and a list by angle distance in which the radio wave intensity by angle and distance for each of the access points 101 to 118 is recorded. In preparing the correct answer data list and the angle distance list, the data investigated in advance is used. On the other hand, the radio wave intensity data of the data storage unit 24 is used to create the radio wave intensity list.

  The distance calculation unit 22 refers to the radio wave intensity pattern storage unit 23 to investigate the radio wave intensity distribution based on the radio wave intensity list and the angular distance list, and estimates the estimated distance for each access point 101 to 118 at each fixed point observation position. Is calculated. The estimated distance calculated here is compared with the correct data of the distance recorded in the correct data list, and if the error of the comparison result is equal to or smaller than the threshold value, it is recorded in the data storage unit 24. In addition, each set of three access points is selected, and the estimated distance calculated from the position of each selected access point and the radio wave intensity is compared with the correct answer data. The combination is recorded in the data storage unit 24 as three access points that can be measured correctly.

  The portable wireless terminal 30 has a function of displaying data and transmitting / receiving data to / from the position grasping device 20 to display a current position (such as which display shelf is currently located). Here, as shown in FIG. 3, the portable wireless terminal 30 includes an output unit 31, an input unit 32, an access point selection unit 33, a radio wave intensity measurement unit 34, a pattern comparison unit 35, a position calculation unit 36, a data storage unit 37, A display unit 38 and a control unit 39 are mounted. The control unit 39 controls the operations of the units 31 to 38, and a store map is stored in the data storage unit 37 in advance.

  The output unit 31 performs a communication start process for the access points 101 to 118 based on a command from the control unit 39. Input data D for this communication start process, that is, radio wave intensity data or the like is input to the input unit 32. Based on the radio wave intensity, the access point selection unit 33 selects which access point 101 to 118 to start communication with, and the radio wave intensity measurement unit 34 measures the radio wave intensity pattern of each access point 101 to 118. This radio wave intensity pattern is transmitted to the position grasping device 20 and fed back to the data storage unit 24.

  The pattern comparison unit 35 accesses the radio wave intensity pattern storage unit 23 of the position grasping device 20 and acquires data of all fixed point observation positions from the radio wave intensity list. Among the acquired data, the measurement data of the radio wave intensity measuring unit 34 is compared with the closest radio wave intensity pattern.

  If the pattern error of the comparison result is equal to or smaller than the threshold value, the position calculation unit 36 estimates the fixed point observation position of the closest fixed point observation pattern as the current position. This estimated position is stored in the data storage unit 37. On the other hand, if the pattern error is not less than or equal to the threshold, the current position is grasped using correctly measured data in the partial data. First, in order to specify the approximate zone of the current position, if there are a plurality of access points whose measurement data of the radio field intensity measurement unit 34 has a reception upper limit value, the midpoint of each access point is set as one of the candidates for the current position. presume. Next, the data accumulating unit 24 of the position grasping device 20 is accessed, and a combination of three access points that can be measured correctly is selected. The process of estimating the current position based on each selected combination is repeated, and each estimated candidate position is stored in the data storage unit 37.

  Then, the center of gravity of the estimated candidate position group stored in the data storage unit 37 is obtained, and the process of removing the estimated candidate positions one by one or more away from the position of the center of gravity one by one is repeated. As a result of this processing, if there is no estimated candidate position that is more than the threshold value from the centroid position of the remaining estimated candidate position group, the centroid position of the remaining estimated candidate position is estimated as the current position. This estimated position is stored in the data storage unit 37.

  Since the display unit 38 displays the estimated position stored in the data storage unit 37 and the ID of the display shelf existing in front of the estimated position, the user K who owns the portable wireless terminal 30 The current position can be easily grasped. That is, according to the present system 1, it is possible to grasp the distance to the closest access point and the current position by using the data stored in the radio wave intensity pattern storage unit 23 (store map, radio wave intensity list, etc.). It becomes possible. Hereinafter, the processing content of this system 1 is demonstrated concretely.

≪Calibration process≫
First, the calibration process (S101 to S111) in the position grasping device 20 will be described with reference to FIG. This calibration processing is roughly divided into pre-calibration processing, that is, processing for creating each list (S102 to S106) and calibration for measuring the current position (S107 to S110). The former process is handled by the relationship table creation unit 21 and the latter process is handled by the distance measurement unit 22.

  S101. S102: This calibration process is performed for the position grasping device 20, the positions / IDs of all display shelves in the store (R01 to R26), the positions / IDs of the access points 101 to 118 (AP1 to AP8), The process is started by inputting data such as passage positions between the display shelves (S101). Here, the position is input in coordinates.

  Based on this input data, a map in which the positions / IDs of the display shelves and the access points 101 to 118 and the positions of the passages between the display shelves are recorded, that is, a store map is created (S102). Here, it is assumed that the access points 101 to 118 are installed at positions where display shelves arranged in parallel with the passage can be identified. The store map may be created manually.

  S103: the positions of a plurality of access points 101 to 118 installed to identify display shelves arranged in parallel with the passage, the types and standards of the access points 101 to 118, and the angles from the access points 101 to 118・ Create a table by angle and distance to record radio field strength by distance.

  S104: A plurality of fixed-point observation positions are set on the store map created in S102, each fixed-point observation position is recorded on the map, and the store map is completed. This fixed point observation position can be determined in a lattice shape including a position that stands when a product is selected in front of the display shelf or an intermediate point between two adjacent access points.

  An example of a completed store map based on FIG. 5 will be described. R01 to R26 indicate IDs of display shelves, AP1 to AP18 indicate IDs of access points 101 to 118, and black spots of P1 to P312 are fixed point observations. The position of the position is shown.

  At the same time, a list of radio wave intensity patterns for recording radio wave intensity patterns at the access points 101 to 118 for the fixed point observation positions P1 to P18, and distances to the access points 101 to 118 for the fixed point observation positions P1 to P312. The correct answer data list for recording is created.

  Table 1 shows an example of the correct data list. Here, the access points 101 to 108 are indicated by IDs, and the distances to the IDs “AP1 to AP18” of the fixed point observation positions P1 to P312 are recorded in “cm” units.

  S105: The radio wave intensity is measured for each of the access points 101 to 118 according to the distance / angle from the access point, and the measurement result is recorded in the list by angle / distance created in S103.

  Table 2 shows an example of a table for each angular distance. Here, the access points 101 to 108 are indicated by IDs, and for each ID “AP1 to AP18”, the angles “60 degrees left”, “45 degrees left”, “30 degrees left”, “0 degrees (front)”, “30 right” The radio field intensities of the linear distances “5 cm” to “10 m” of “degree”, “45 degrees right”, and “60 degrees right” are recorded. The values of the angle and the linear distance shown here are examples and may be set more finely.

  S106: The radio wave intensity from each of the access points 101 to 108 is measured for each fixed point observation position P1 to P312 recorded in the store map in S104, and is recorded in the radio wave intensity list created in S104. As the radio wave intensity recorded here, the accumulated data of the data accumulating unit 24, that is, the radio wave intensity measured by the radio wave intensity measuring unit 34 is used.

  Table 3 shows an example of a list of radio wave intensity patterns. Here, the access points 101 to 108 are indicated by IDs, and an array (vector) of radio wave intensity from the IDs “AP1 to AP18” of the fixed point observation positions P1 to P312 is recorded.

  S107: The distribution of the radio wave intensity is investigated based on the data recorded in each list in S105 and S106, and the relational expression (linear approximation) between the distance and the radio wave intensity is statistically processed for each of the access points 101 to 118.

  That is, as calibration for measurement, the portable wireless terminal 30 identifies the distance to each access point, the radio wave intensity at that time, and the access point at a standard position in front of each display shelf (in front of the access point). IDs “AP1 to AP18” are obtained, parameters (α, β) for distance measurement are obtained, and stored in the data storage unit 24 in pairs with the measured position information (coordinates) of the portable wireless terminal 30. Keep it. Using this parameter, the estimated distance “y” that can be calculated from the radio wave intensity “x” is obtained by the linear approximation formula “y = αx + β”.

  In this calibration process, data is acquired so that the distance can be calculated in front of each display shelf and other characteristic places while moving the portable wireless terminal. Then, the radio wave intensities from all the access points 101 to 118 are measured for each fixed point observation position determined in S104, and after executing the process of S106, based on the data recorded in each list in S105 and S106, FIG. And the linear approximate expression “y = αx + β” of the distance and the radio wave intensity is calculated for each of the access points 101 to 118 to calculate the estimated distance. The reason why the relationship between the distance and the radio wave intensity is obtained for each of the access points 101 to 118 in this way is considered that the relationship between the distance and the radio wave intensity is not constant depending on the position of the pillar of the building, the display shelf or the access point. Because.

  In the distribution example of FIG. 6, R601 to R607 indicate display shelves, AP601 to AP607 indicate access points, and P601 to P607 indicate distances from the access points AP601 to AP607 to the portable wireless terminal 30.

  S108: The radio field intensity is maximized from the data recorded in each list in S105 and S106 and is saturated, and the maximum value continues when there is a situation where the distance cannot be estimated only by the radio field intensity value. The distance is grasped and recorded in the data storage unit 24. In this case, this data alone indicates that the current position is a close distance from the access points 101 to 118, but it is not required as a measurement point. Therefore, a process for enabling distance calculation from partial data at a plurality of peripheral access points is performed after S109.

  S109: The estimated distance obtained in S107 is verified based on the recorded data of the correct data list recorded in S104, that is, the distance value from the fixed point measurement position to each of the access points 101 to 118. Here, the value of the estimated distance obtained from the radio wave intensity by the linear approximation formula of S107 is compared with the recorded data in the correct data list, and if the error between them is equal to or less than the threshold value (εcm), it is determined that the correct distance is obtained. It is determined and recorded in the data storage unit 24 as an access point that can be measured correctly.

  S110. S111: A combination of three access points that can be measured correctly based on the recorded data in the correct data list recorded in S104 is obtained. That is, among the access points 101 to 118, a plurality of combinations of three access points are selected, and the estimated distance obtained by the linear approximation formula of S107 from the radio field intensity of each selected access point is recorded in the correct data list. Compare with the data.

  As a result of the comparison, if the error between them is equal to or less than the threshold value (εcm), it is determined that it has been obtained correctly, the combination is recorded in the data storage unit 24 as three access points that can be measured correctly, and the calibration process is terminated. (S111). Here, when setting is made so that the resolution of the current position at which the fixed point observation position is to be obtained (or subdivided more than the resolution), all the radio wave intensities from the access points 101 to 118 are set as vectors, By comparing the radio field intensity of all the fixed-point observation positions, the closest fixed-point observation position can be made the current position. In addition, as the number of fixed point observation positions increases, the possibility that the current position is obtained more accurately increases.

≪Current position measurement process≫
Next, processing contents (S201 to S213) for grasping the current position of the user in the store will be described with reference to FIG. Here, it is assumed that the user K receives radio waves from each of the access points 101 to 118 when moving inside the store with the portable wireless terminal 30.

  S201.202: When communication start processing is started from the output unit 31 of the portable wireless terminal 30 to each of the access points 101 to 118 (S201), each of the access points 101 to 118 where the portable terminal 30 is set in the store. For each ID “AP1 to AP18”, the radio wave intensity (reception intensity) is recorded in the reception intensity list of the data storage unit 37 (S202).

  That is, the mobile terminal 30 receives the radio wave intensity data D of each of the access points 101 to 118 by the input unit 32, and requests the radio wave intensity measurement unit 34 to measure the radio wave intensity after the reception. At this time, the radio wave intensity measuring unit 34 measures the radio wave intensity from the access points 101 to 118 based on the radio wave intensity data D, and enters the radio wave intensity in the reception intensity list for each access point ID that can be consulted. For the access points that could not be received here, “0” is entered in the field of radio wave intensity in the reception intensity list.

  Table 4 shows an example of the received intensity list. Here, the radio wave intensity measured at the measurement point (the position of the user K) is recorded for each ID “AP1 to AP18” of the access points 101 to 118. This received intensity list is transmitted to the position grasping device 20 and stored in the data storage unit 24.

  S203. S204: The pattern comparison unit 35 compares the data of the reception intensity list recorded in S202 with the data of the radio wave intensity pattern list recorded in S106 (S203), and the error from the nearest fixed point observation position is “ It is determined whether it is within “δ” (S204).

  That is, the portable radio terminal 30 accesses the position grasping device 20 and refers to the radio wave intensity list in the radio wave intensity pattern storage unit 23 to acquire the radio wave intensity patterns at all the fixed point observation positions. Here, among the radio wave intensity patterns in the radio wave intensity list, a pattern that is closest to the radio wave intensity pattern in the reception intensity list is compared, and it is determined whether or not the pattern error of the comparison result is within a threshold “δ”. As a result of the determination, if it is within the threshold “δ”, the process proceeds to S205, while if it is not within the threshold “δ”, the process proceeds to S206.

  S205: If the determination in S204 is within the threshold “δ”, the position calculation unit 36 estimates the fixed point observation position of the compared radio wave intensity pattern as the current position. The estimated position and the ID of the display shelf located in front of the estimated position are set as a set and stored in the data storage unit 37 as current position information at time t.

  If the number of fixed-point observation positions that have been measured in advance is increased and the number of current position estimation points to be obtained is equal to or greater than the number of fixed-point observation positions that are closest to the measured data, the current position can be sufficiently accurate. Conceivable. However, when the error from the closest fixed point observation position is equal to or greater than the threshold “δ”, it is considered that the current position cannot be accurately estimated.

  In other words, when all of the measured radio field intensity data is used, errors including the threshold value “δ” or more are included, and the current position cannot be obtained accurately. Therefore, the measurement data is grouped into partial data sets for every three points. Separately, the current position is measured. This means that accurate measurement data is not obtained due to unstable radio wave conditions.

  Therefore, the position calculation unit 36 uses a method of grasping the current position using the accurately measured data by using the partial data in S206 to S211. At this time, since the candidate position estimated using inaccurate data is expected to be greatly deviated, a measurement process for performing more accurate position estimation is performed by removing an estimated position having a large estimation error from the set. .

  S206: If the determination in S204 is not within the threshold “δ”, when there are a plurality of access points whose radio field intensity is the reception upper limit value in the reception intensity list, the midpoint of each access point is set as one of the estimated candidate positions. Know the location of multiple high-powered access points.

S207: Select the combination access point correctly measurable three from receivable access points A reception intensity table, the process of estimating the current position repeatedly kinds _A C _3, the estimated position candidate data storage unit 37.

  That is, the portable wireless terminal 30 accesses the position grasping device 20 and acquires a combination of three access points that can be correctly measured from the data storage unit 24. According to the combination acquired here, a combination of three access points that can be measured correctly is selected from the number A of access points in the received intensity list.

In addition, the radio wave intensity of each access point selected from the received intensity list is obtained, and the radio wave intensity is converted into a distance using a linear approximation expression “y = αx + β”, and the three points of distance data and the three points of access point are converted. Calculate the position coordinates from the coordinates. Repeating types _A C ₃ in accordance with the number of combinations of this calculation. The calculated _A C ₃ or coordinates as the estimated position candidates is stored in the data storage unit 37.

  Here, it is assumed that the parameter (α.β) is acquired from the data storage unit 24 simultaneously with the combination of access points. In addition, it is assumed that the coordinate data of the access points 101 to 118 is stored in the data storage unit 37 in advance.

  S208 to S211: A centroid (coordinate) is obtained from the set of estimated position candidates stored in the data storage unit 37 in S207, and one point of the estimated position candidate that is most distant from the position of the centroid by the threshold “γ” or more is removed. (S208). As a result, it is determined whether or not the estimated position candidates that are separated by the threshold “γ” or more remain (S209), and if remaining, S208 is re-executed. That is, the centroid position of the remaining estimated position candidates is obtained, and the process of S208 is repeated until there are no estimated position candidates that are more than the threshold “γ” from the centroid position.

  As a result, if there is no estimated position candidate that is more than the threshold “γ”, the center of gravity position of the remaining estimated position candidate is estimated as the current position (S210). The estimated position and the ID of the display shelf located in front of the estimated position are set and stored in the data storage unit 37 as current position information at time t (S211).

  S212. S213: The control means 39 causes the display unit 35 to display the current position information at the time t stored in the data storage unit 37 in S205 or S211, that is, the estimated position and the display shelf ID positioned in front of the estimated position, The process ends (S213). This display result is transmitted to the position grasping device 20 and stored in the data storage unit 24.

  According to the present system 1, the distance between the mobile wireless terminal 30 and the plurality of access points 101 to 118 is the shortest distance, and the reception radio waves from the plurality of access points 101 to 118 are the closest because of the high intensity. Even when an access point cannot be determined, distance calculation can be performed using a plurality of neighboring access points (S109.S110.S207 to S210), so that the current position can be estimated more accurately. it can.

  Particularly, in order for the position grasping device 20 to compare the correct data in the correct data list with the actually measured estimated distance from the portable wireless terminal to the access point (S109.S110), the influence of human traffic, obstructions, etc. Even if there is some disturbance in the radio wave condition, it is possible to obtain multiple candidates for the estimated distance from the mobile wireless terminal to the access point by using the information of many access points, and the reliability of the estimation is also guaranteed. ing.

  Also, when grasping the current position, if the fixed-point observation positions are subdivided in advance in the measurement area and prepared in large numbers, by comparing with a large number of fixed-point observation data (S204.S205), the nearest fixed-point observation place is The position can be estimated, and the current position can be easily obtained.

  On the other hand, since the mobile radio terminal 30 calculates a current position estimation candidate using a plurality of sets of radio field strengths at three correctly measurable access points and obtains the center of gravity (S207 to S210), the radio wave condition is unstable. The accuracy of the estimated current position can be increased even when some noise or the like is mixed in the measurement data or missing. At this time, since the estimated value greatly deviating from the position of the center of gravity is removed (S208.S209), a more reliable and accurate current position is obtained.

  In addition, this invention is not limited to the said embodiment, It can deform | transform within the range described in each claim. For example, in the above embodiment, the description is based on the arrangement of the wireless LAN access point assuming a display shelf in the supermarket store, but each booth in the exhibition hall, each poster panel for the explanatory meeting, or a fixed place is accessed. A usage form in which points are arranged at short intervals as identification targets may be used.

  Further, the pattern comparison unit 35 and the position calculation unit 36 may be provided not in the portable wireless terminal 30 but in the position grasping device 20. In this case, the current position estimation process (S203 to S211) is performed based on the received intensity list of the data storage unit 24, and the final current position information (estimated position / display shelf ID) is obtained. To be displayed on the display unit 30. As a result, the processing load of the portable wireless terminal 30 can be reduced, and this is particularly effective when the processing capability of the portable wireless terminal 30 is small.

  Further, the comparison target data with the received strength list data in S203 may include the angular distance list data recorded in S105 in addition to the radio field strength list in S106.

≪Programs≫
The present invention can also be configured as a program for causing a computer to function as a part or all of the units 21 to 26.31 to 38 of the system 1. According to this program, S101 to S111. Cause the computer to execute all or some of steps S201 to S213.

  The program can be provided through a network such as a website or e-mail. The program is stored in a recording medium such as a CD-ROM, DVD-ROM, CD-R, CD-RW, DVD-R, DVD-RW, MO, HDD, BD-ROM, BR-R, BD-RE. It is also possible to record, save and distribute. This recording medium is read using a recording medium driving device, and the program code itself realizes the processing of the above embodiment, so that the recording medium also constitutes the present invention.

DESCRIPTION OF SYMBOLS 1 ... Position grasp system 20 ... Position grasp device 21 ... Relation table creation part (relation data creation means)
22 ... Distance measuring unit (access point defining means)
23 ... Radio wave intensity pattern storage unit 24 ... Data storage unit (storage unit)
DESCRIPTION OF SYMBOLS 25 ... Communication part 26.39 ... Control part 30 ... Portable radio | wireless terminal 31 ... Output part 32 ... Input part 33 ... Access point selection part 34 ... Radio wave intensity measurement part 35 ... Pattern comparison part 36 ... Position calculation part (position estimation means)
37 ... Data storage unit 38 ... Display unit 101-118 ... Wireless LAN access point AP1-AP18 ... Wireless LAN access point ID
P1 to P312 ... Fixed point observation position R01 to R26 ... Display shelf ID

Claims (9)

A position grasping method for grasping the position of the portable wireless terminal based on the radio field intensity of the portable wireless terminal with respect to the access point of the communication means installed in each measurement object in the measurement area,
The relational data creation means includes a map that records the position of each measurement target in the measurement area, the position of each access point, a plurality of fixed point observation positions determined in advance in the measurement area, and each access point for each fixed point observation position. A first table in which the distance of each access point is recorded, a second table in which the field strength according to the angle and distance at each access point is recorded, and a third table in which the field strength at each access point at each fixed point observation position is recorded. A relationship data creation step to be created in
The access point defining means calculates an estimated distance from the radio wave intensity to the fixed point observation position for each access point based on the recorded data in the second table and the third table, and an error between the estimated distance and the recorded data in the first table is An access point defining step that predetermines a combination of a plurality of access points below a threshold;
If the position estimation means is such that the error between the radio wave intensity of the access point that can be received by the portable wireless terminal and the recorded data of at least the third table of the second table and the third table is not less than a threshold value, according to the combination A position estimation step of selecting a combination of a plurality of receivable access points, estimating a distance from each selected access point from the radio wave intensity, and obtaining a current position;
A position grasping method characterized by comprising: In the access point defining step, a combination of three access points whose error is equal to or less than a threshold value is accumulated in an accumulation unit,
In the position estimation step, if the error is not less than a threshold value, a combination of access points is acquired from the storage means, and three access points are selected from a plurality of receivable access points according to the combination,
The plurality of estimated position candidates are obtained based on the position of each selected access point and the estimated distance from each access point, and the center of gravity position of the estimated position candidate group is estimated as the current position. Location method. The position estimation step includes removing estimated position candidates that are separated from a center of gravity of the estimated position candidate group by a threshold or more, and estimating the center of gravity of the estimated position candidate group after the removal as a current position. How to find the location. The position estimation method according to any one of claims 1 to 3, wherein the position estimation step estimates a fixed point observation position of the radio wave intensity as a current position if the error is equal to or less than a threshold value. A position grasping system for grasping the position of the portable wireless terminal based on the radio field intensity of the portable wireless terminal with respect to the access point of the communication means installed in each measurement object in the measurement area,
A map that records the position of each measurement target in the measurement area, the position of each access point, a plurality of fixed-point observation positions set in advance in the measurement area, and the distance to each access point for each fixed-point observation position Creation of relational data to create in advance a table, a second table that records the radio field intensity according to the angle and distance at each access point, and a third table that records the radio field intensity of each access point at each fixed point observation position Means,
An estimated distance from the radio wave intensity to the fixed point observation position is calculated for each access point based on the recorded data in the second table and the third table, and a plurality of accesses in which an error between the estimated distance and the recorded data in the first table is equal to or less than a threshold value. An access point defining means for determining a combination of points in advance;
If the error between the radio wave intensity of the access point that can be received by the portable wireless terminal and the recorded data of at least the third table of the second table and the third table is not less than a threshold value, a plurality of receivables according to the combination A position estimation means for selecting a combination of access points, and estimating the distance from each selected access point from the radio wave intensity to obtain a current position;
A position grasping system characterized by comprising: The access point defining means accumulates, in the accumulation means, a combination of three access points whose error is equal to or less than a threshold value,
The position estimating means acquires a combination of access points from the storage means if the error is not less than a threshold, and selects three access points from a plurality of receivable access points according to the combination,
The plurality of estimated position candidates are obtained based on the position of each selected access point and the estimated distance from each access point, and the center of gravity position of the estimated position candidate group is estimated as the current position. Positioning system. The position estimation means removes an estimated position candidate that is more than a threshold from the center of gravity of the estimated position candidate group, and estimates the center of gravity of the estimated position candidate group after the removal as a current position. The location tracking system described. The position grasping system according to any one of claims 5 to 7, wherein the position estimating unit estimates a fixed point observation position of the radio wave intensity as a current position if the error is equal to or less than a threshold value.   A position grasping program for causing a computer to function as each means of the position grasping system according to any one of claims 5 to 8.

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