JP2011075505A - Position calculation device, position calculation method, and position calculation program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To integrate position coordinates calculated at each local region into one coordinate system. <P>SOLUTION: A local coordinate calculation part 230 of a position calculation device 20 detects a plurality of local regions constituted of a plurality of sensors, respectively, and calculates each position coordinate of the plurality of sensors constituting the local regions relative to each local region based on a distance between each sensor and a transmission/reception terminal 10. An integrated region extraction part 241 extracts two or more local regions having in common, a prescribed number of sensors from among the plurality of local regions as mutually unifiable regions. An integration processing part 242 calculates a distance between sensors and the reliability of the distance between the sensors in each extracted local region, performs weighting according to the reliability of the distance between the sensors, calculates the distance between the sensors subjected to weighting correction, and calculates the position coordinate of each sensor in the coordinate system wherein local regions are integrated based on the weighted average of the distance between the sensors subjected to weighting correction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a position calculation device, a position calculation method, and a position calculation program.

  Conventionally, in an indoor user tracking system (user position calculation system), a method of calculating the position of a user in a space using a sensor installed in the environment, or attaching a sensor to a user or an object to determine the relative position of each user. A combination and a method of calculating the position of a user or an object in a space is used.

  Non-Patent Document 1 describes a sensing room that can acquire the position of a person by placing sensors around the room. According to this technology, it is possible to accurately measure the position of a human in the sensing room.

  Patent Document 1 describes a technique for calculating a relative position between a plurality of fixing devices whose positions are unknown and a moving device whose position is unknown using a relative distance between the fixing device and the moving device. This technology can be expected to reduce system installation costs.

Japanese Patent No. 4057023

Mori, “Intelligent House to Help Learn Life Patterns”, Network Robot Society, pp20-24, 2005

  However, in the sensing room described in Non-Patent Document 1, 500 or more sensors are installed in one room, and not only the installation cost but also labor required for calibration is increased, and it cannot be said that it is a general-purpose system.

  Moreover, in the technique described in Patent Document 1, in order to calculate the positions of all the fixed devices and the moving device on one coordinate system, it is necessary to simultaneously measure the distance between the all fixed devices and the moving device. Is difficult. Therefore, only position calculation on the coordinate system set for each combination of the fixed devices that have performed distance measurement can be realized.

  The present invention has been made in view of the above circumstances. A relative coordinate system generated based on the relative positional relationship of the fixing device (hereinafter, an identification number assigned to the relative coordinate system is referred to as a local region ID). An object of the present invention is to provide a position calculation device, a position calculation method, and a position calculation program capable of accurately integrating position coordinates calculated every time) into one coordinate system.

The position calculation apparatus according to the present invention has the following configuration.
(1) In an environment including a plurality of sensors, a position calculation device that receives distance information between a terminal that can move in the environment and each of the plurality of sensors, and calculates the position coordinates of the terminal. , Detecting a plurality of local regions each composed of a plurality of sensors, and based on the distance between the terminal and each of the plurality of sensors, in each of the local regions, a plurality of sensors constituting the local region First coordinate calculation means for calculating position coordinates; and integrated area extraction means for extracting two or more local areas sharing a predetermined number of sensors among the plurality of local areas as areas that can be integrated with each other; In each of the two or more local regions extracted as regions that can be integrated, the inter-sensor distance and the reliability of the inter-sensor distance are calculated, and the two or more local regions are respectively calculated. A coordinate system in which the two or more local regions are integrated on the basis of the corrected inter-sensor distance based on the corrected inter-sensor distance. And a second coordinate calculating means for calculating the position coordinates of each sensor.
According to this aspect, the position coordinates calculated for each local region can be accurately integrated into one coordinate system.

The position calculation method according to the present invention is configured as follows.
(2) A position calculation apparatus including a first coordinate calculation unit, an integrated region extraction unit, and a second coordinate calculation unit, and an environment including a plurality of sensors, the terminal that can move in the environment, and the plurality A position calculation method used in a position calculation device that receives distance information between each of the sensors and calculates the position coordinates of the terminal, wherein each of the first coordinate calculation means includes a plurality of sensors. Detecting a plurality of local regions, and calculating the position coordinates of the plurality of sensors constituting the local region in each of the local regions based on the distance between the terminal and each of the plurality of sensors. The integrated region extraction means extracts two or more local regions sharing a predetermined number of sensors from the plurality of local regions as regions that can be integrated with each other, and calculates the second coordinates. The means calculates the inter-sensor distance and the reliability of the inter-sensor distance in each of the two or more local areas extracted as areas that can be integrated, and the inter-sensor distance calculated in each of the two or more local areas And calculating the inter-sensor distance after the weight correction, and calculating the position coordinates of each sensor in the coordinate system integrating the two or more local regions based on the corrected inter-sensor distance. The calculation mode is used.
According to this aspect, the position coordinates calculated for each local region can be accurately integrated into one coordinate system.

The position calculation program according to the present invention has the following configuration.
(3) In an environment including a plurality of sensors, it is used for a position calculation device that receives distance information between a terminal that can move in the environment and each of the plurality of sensors and calculates the position coordinates of the terminal. The computer detects a plurality of local regions each composed of a plurality of sensors, and based on the distance between the terminal and each of the plurality of sensors, a plurality of components constituting the local region in each of the local regions First coordinate calculation means for calculating the position coordinates of the sensor, integrated area extraction means for extracting two or more local areas sharing a predetermined number of sensors among the plurality of local areas as areas that can be integrated with each other; In each of the two or more local regions extracted as regions that can be integrated, the inter-sensor distance and the reliability of the inter-sensor distance are calculated, and the two or more local regions are calculated. Weighting is performed according to the reliability of the distance between sensors calculated in each region to calculate the distance between sensors after weight correction, and the two or more local regions are integrated based on the distance between sensors after the weight correction. A mode is made to function as second coordinate calculation means for calculating the position coordinates of each sensor in the coordinate system.

  According to this aspect, the position coordinates calculated for each local region can be accurately integrated into one coordinate system.

  According to the configuration of the present invention, the position coordinates calculated for each local region can be accurately integrated into one coordinate system.

The system configuration figure showing an example of the position calculation system concerning one embodiment of the present invention. The block diagram which shows the functional structure of a transmission / reception terminal and a position calculation apparatus. The figure which shows an example of the data structure stored in the measurement distance table with which a data storage part is equipped. The figure which shows an example of the data structure stored in the local coordinate table with which a data storage part is equipped. The flowchart which shows the whole process performed in a position calculation apparatus. The flowchart of the process which a local coordinate calculation part performs. The figure for demonstrating how to determine the position coordinate in a new local area | region. The flowchart of the process which an integrated area | region extraction part performs. The flowchart of the production | generation process of the measurement sensor list which an integrated process part performs. The flowchart of the sensor matching process which an integrated process part performs. The flowchart of the position coordinate correction process which an integrated process part performs. The flowchart of the calculation process of the distance between transmitters which an integrated process part performs. The figure which shows an example of a local area | region. The figure for demonstrating the distance between transmitters calculated in a local region, and reliability. The figure which shows the difference in the distance between transmitters each calculated in two local area | regions. The figure for demonstrating the production | generation of the undirected graph by an integrated process part. The figure which represented the distance between transmitters by the weighted average distance in the above-mentioned undirected graph. The figure which shows the mode of correction of the position coordinate of a transmitter.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a system configuration diagram showing an example of a position calculation system according to an embodiment of the present invention. As shown in FIG. 1, the user U carries the transmitting / receiving terminal 10 and carries it in the system. The (n + 1) transmitters # 0 to #n are installed at arbitrary locations in the system environment (for example, one room). However, n is 3 or more and an arbitrary positive integer.

  In this position calculation system, at least two local regions are integrated, and one local region is composed of at least three transmitters. Therefore, four or more transmitters are provided. ID: i is assigned to the i-th transmitter #i, and its position coordinate is, for example, X0_i = (X0i, Y0i) in the coordinate system of the local area ID0 by the transmitters # 0, # 1, and # 2. expressed.

  The transmitters # 0 to #n are, for example, transmission terminals that generate waves such as radio waves and sound waves. The transmission / reception terminal 10 receives the radio waves and sound waves from the transmitters # 0 to #n, and transmits the transmitters. The distance di (t) from is measured. However, mediation of communication between the transmitters # 1 to #n and the transmission / reception terminal 10 is not limited to radio waves or sound waves, and any media may be used as long as conversion to distance is possible. The transmitters # 0 to #n transmit the current time (transmission time) and information on the transmitter ID unique to the transmitter by radio waves or sound waves at predetermined time intervals.

  In the example illustrated in FIG. 1, a sensor system is illustrated in which a transmission / reception terminal 10 carried by the user U receives radio waves or sound waves transmitted from the transmitters # 0 to #n. May carry a transmitter and a receiver installed in the environment.

  In the following, an example in which a transmitter (sensor) is fixed in the environment and the user carries the receiver (transmission / reception terminal 10) in the environment will be described based on the example of FIG. The position coordinate of the transmission / reception terminal 10 at time t is represented by X0_h (t) = (X0h (t), Y0h (t)) in the coordinate system in which the local region ID is 0.

  The position calculation device 20 calculates various position coordinates such as calculation of position coordinates of each transmitter and transmission / reception terminal 10 in the reference coordinate system and calibration of the calculated position coordinates based on information from the transmission / reception terminal 10 carried by the user U. A computer system that executes processing. The position calculation device 20 includes a processor, a program memory, and a work memory (not shown), and controls various processes according to the present embodiment when the processor executes a predetermined program stored in the program memory.

  FIG. 2 is a block diagram illustrating functional configurations of the transmission / reception terminal 10 and the position calculation device 20 in the position calculation system.

  Transmitters # 0 to #n transmit the current time (transmission time) and transmitter ID information by radio waves or sound waves at predetermined time intervals.

  The transmission / reception terminal 10 includes a reception unit 101, a distance measurement unit 102, and a transmission unit 103. The receiving unit 101 receives radio waves or sound waves transmitted from transmitters (# 0 to #n). The distance measuring unit 102 calculates the propagation time of radio waves or sound waves based on the current time (reception time or measurement time) and the transmission time from the transmitter, and between the transmission / reception terminal 10 and the transmitter based on the propagation time. The distance di (t) at the measurement time t is calculated. The transmission unit 103 transmits the calculated distance (measurement distance) to the position calculation device 20 in association with the transmitter ID and the measurement time.

  The distance calculation between the transmitter and the transmission / reception terminal 10 may be performed by combining radio waves and ultrasonic waves. In this case, a calling instruction for instructing transmission of ultrasonic waves is transmitted from the transmission / reception terminal 10 to the transmitter #i by radio waves, and the transmitter #i that has received the radio waves emits ultrasonic waves. The distance di (t) between the transmitter #i and the transmission / reception terminal 10 is obtained by multiplying the time difference between the time when the transmission / reception terminal 10 receives the ultrasonic wave and the time when the transmitter #i emits radio waves by the speed of sound. Is calculated.

  The position calculation device 20 includes a reception unit 210, a data storage unit 220, a local coordinate calculation unit 230, and a local coordinate integration unit 240.

  The receiving unit 210 receives measurement distance, transmitter ID, and measurement time data transmitted from the transmitter / receiver terminal 10 to each transmitter.

  The data storage unit 220 is a storage device including a hard disk device, a flash memory, and the like. The data storage unit 220 includes a measurement distance table 221 shown in FIG. 3, a local coordinate table 222 shown in FIG. 4, and a reference area information storage unit 223. Data sent from the transmission / reception terminal 10 is held in the measurement distance table 221.

  FIG. 3 is a diagram illustrating an example of a data configuration stored in the measurement distance table 221 provided in the data storage unit 220. As illustrated in FIG. 3, the measurement distance table 221 stores the measurement time t and the measurement distance di (t) at the measurement time t, corresponding to the transmitter ID of each transmitter.

  FIG. 4 is a diagram illustrating an example of a data configuration stored in the local coordinate table 222 provided in the data storage unit 220. As shown in FIG. 4, the local coordinate table 222 includes, for each local area, a local area ID, a sensor (transmitter) included in the area, coordinates of each sensor, and measurement between each sensor and the transmission / reception terminal 10. The distance, the reliability described later, the ID of the local area that can be integrated, the average measurement distance, and the position coordinates of the transmission / reception terminal 10 are stored.

  The reference area information storage unit 223 stores information on a reference local area that provides a reference coordinate system. The reference local region may be determined in advance according to a setting operation by the user.

  The local coordinate calculation unit 230 generates and updates the storage contents of the local coordinate table 222 based on the data received by the reception unit 210.

  The local coordinate integration unit 240 includes an integrated region extraction unit 241, an integration processing unit 242, and an input / output unit 243. The integrated region extraction unit 241 extracts and sets two local regions sharing a predetermined number or more transmitters as local regions that can be integrated. The integration processing unit 242 performs integration processing of the local regions extracted as being capable of integration. The input / output unit 243 includes a display device for outputting the integration result. Alternatively, the input / output unit 243 may be connected to a storage device (not shown), and the integration result may be output and stored in the storage device.

  Next, the operation of the position calculation device 20 configured as described above will be described.

  FIG. 5 is a flowchart showing the entire processing executed in the position calculation device 20.

  The receiving unit 210 receives data including the transmitter ID, measurement time, and measurement distance of at least one transmitter (#i) from the transmission / reception terminal 10 (step S501). The reception unit 210 also outputs the received data to the measurement distance table 221 and the local coordinate calculation unit 230 of the data storage unit 220. In the measurement distance table 221, the data of the measurement time and the measurement distance are updated corresponding to the transmitter ID: i of the at least one transmitter (#i).

  The local coordinate calculation unit 230 determines whether or not a new local region is created based on the transmitted transmitter ID, measurement time, and measurement distance data (step S502).

  If the local area included in the received data is not stored in the local coordinate table 222, it is necessary to create a new local area (Yes in step S502). In this case, the local coordinate calculation unit 230 generates an ID that does not exist in the local coordinate table 222 as a new local area ID (step S503).

  If the local area included in the received data is already stored in the local coordinate table 222, a new local area is not created (No in step S502). In this case, the local coordinate calculation unit 230 selects, from the local coordinate table 222, a local area ID that is included in the received data and is an update target (step S504).

  The local coordinate calculation unit 505 includes a local area ID newly created in step S503 or a transmitter (sensor) that configures a local area corresponding to the local area ID selected in step S504 and the latest information up to the transmission / reception terminal 10. The measurement distance is added to the stored contents of the local coordinate table 222, and the position coordinates of the transmitter (sensor) constituting the local area corresponding to the local area ID, the latest position calculation time, the reliability, and the value of the average measurement distance And the stored contents of the local coordinate table 222 are updated (step S505). When a new local area is detected, the latest measured distance from each sensor to the transmitting / receiving terminal 10 is added to the stored contents of the local coordinate table 222 in association with the newly created local area ID, and is calculated. The position coordinates of the sensor, the latest position calculation time, the reliability, and the value of the average measurement distance are stored in the local coordinate table 222, and the stored contents are updated. The local coordinate calculation unit 230 also stores the ID of each sensor included in the new local region in the local coordinate table 222.

  On the other hand, when the local region ID to be updated is selected in step S504, the position coordinates of the sensor corresponding to the selected local region ID, the latest position calculation time, the reliability, and the average measurement in the local coordinate table 222. The distance value is updated to the calculated value. The local coordinate calculation unit 203 also calculates the measurement distance of each sensor included in the selected local region, and corresponds to the local region ID of the selected local region in the local coordinate table 222. Add position coordinate value.

  Next, in the local coordinate integration unit 240, the integrated region extraction unit 241 determines whether there is a region that can be integrated among the local regions stored in the local coordinate table 222 (step S506). The determination result is sent to the integration processing unit 242.

  The integration processing unit 242 integrates the local regions based on the determination result (step S507). The integration result may be output via the input / output unit 243.

  In addition, although the example which implements the process of the local coordinate integration part 240 after the process of the local coordinate calculation part 230 was described in FIG. 2, the process of the local coordinate calculation part 230 and the process of the local coordinate integration part 240 were isolate | separated. The local coordinate calculation unit 230 updates the stored contents of the local coordinate table 222 of the data storage unit 220 and terminates the process, and the local coordinate integration unit 240 performs a predetermined timing (for example, at a predetermined time interval). Alternatively, the process of step S506 in FIG. 5 may be started (by an activation instruction from the input / output unit).

  Next, the processing executed by the local coordinate calculation unit 230 and the local coordinate integration unit 240 will be described in more detail.

FIG. 6 is a flowchart showing details of processing executed by the local coordinate calculation unit 230. The process shown in FIG. 6 corresponds to the process of steps S502 to S505 in FIG.
When the reception unit 210 stores the received data in the data storage unit 220, the local coordinate calculation unit 230 acquires information in the local coordinate table 222 of the data storage unit 220 (step S601). The local coordinate calculation unit 230 generates all combinations of three or more IDs from the transmitter ID included in the received data (step S602). The local coordinate calculation unit 230 selects one combination from the generated combinations (step S603). Here, M is the number of transmitter IDs received by the receiving unit 210.

  The local coordinate calculation unit 230 determines whether or not the selected combination of IDs is a combination of representative sensors included in any local region stored in the local coordinate table 222 (step S604).

  If the selected ID combination is a combination of representative sensors included in any of the local areas stored in the local coordinate table 222 (Yes in step S604), the local coordinate calculation unit 230 selects the selected combination. The local area ID of the local area corresponding to the combination of IDs is selected as a processing target (step S607).

  If the selected combination of IDs is not a combination of representative sensors included in any of the local areas stored in the local coordinate table 222 (No in step S604), the steps for all combinations generated in step S602 are performed. It is determined whether or not the process of S604 has been performed (step S614). If there is a combination that has not yet been processed in step S604 (No in step S614), the process returns to step S603 to select another combination, and the subsequent processing is repeated. On the other hand, if the processing has been completed for all the combinations (Yes in step S614), the local coordinate calculation unit 230 assumes that a new local region is configured by the transmitter specified by the selected ID combination. Sets the information of the new local region in the local coordinate table 222 (step S606). The information on the new local area to be set includes the local area ID of the new local area, information on the representative transmitter of the local area, its position coordinates, and the like. The local area ID may be assigned, for example, from 0 to a sequential number.

  FIG. 7 is a diagram for explaining how to determine position coordinates in a new local region. Three representative transmitters are arbitrarily selected from the selected combination of IDs, and as shown in FIG. 7, one of the three transmitters is set as the origin, and the other is set on the x-axis. The remaining one representative transmitter is determined to exist in the + direction of the y-axis, and a coordinate system in a new local region is set. The local coordinate table 222 stores a local area ID assigned to the new local area and a representative transmitter ID that defines the coordinate system.

  The local coordinate calculation unit 230 sets the local region ID selected in step S605 or the local region ID newly given in step S606 as the ID of the processing target region, and the measurement time of the transmitter included in the processing target region and Measurement distance data is acquired from the measurement distance table 221 (step S607). The local coordinate calculation unit 230 detects the number N of measurement times at which measurement distances are stored for all M transmitters included in the processing target region from the measurement distance table 221 (step S608).

  The local coordinate calculation unit 230 determines whether or not the conditional expression MN> 2M + 2N indicating whether the relative distance of each transmitter can be calculated is satisfied (step S609). If the conditional expression MN ≧ 2M + 2N is not satisfied (No in step S609), the relative distance between the transmitters cannot be calculated, and the process ends.

  On the other hand, when the conditional expression MN ≧ 2M + 2N is satisfied (Yes in step S609), the relative distance of each transmitter can be calculated.

For example, in the local region where the local region ID is 0, the measurement distance di (t) between the transmitter #i and the transmission / reception terminal 10 can be obtained from the following equation (1).

  Here, (X0i, Y0i) (= X_0) represents the position coordinates of the transmitter #i in the local area where the local area ID is 0. Further, the position coordinates of the transmission / reception terminal 10 in the local region at time t are represented by X0_h (t) = (X0h (t), Y0h (t)).

Accordingly, for the N measurement times selected in step S608, the relational expression (2) between the measurement distance and the position coordinates of each transmitter and the transmission / reception terminal 10 is generated by the local coordinate calculation unit 230 (step S610). .

  The local coordinate calculation unit 230 solves the simultaneous equation (2) and calculates the relative position coordinates between the transmitter and the transmission / reception terminal 10 at each measurement time (step S611).

  As shown in FIG. 7, when one representative transmitter is at the origin and the other representative transmitter is on the x-axis, 2M−3 (3 In the case of the three-dimensional position coordinates, there are 3M-6), and there are 2N (3N in the case of the three-dimensional position coordinates) unknown variables as the two-dimensional position coordinates of the transmission / reception terminal 10. The number of equations included in the simultaneous equations (2) is MN. Therefore, if the conditional expression MN ≧ 2M + 2N−3 (MN ≧ 3M + 3N−6 in the case of three-dimensional coordinates) is satisfied in step S609, the position coordinates of the transmitter and the transmission / reception terminal 10 at each time are calculated (estimated). Can do. For example, when the number of transmitters included in the selected local region is three, the conditional expression is satisfied when N ≧ 3. Therefore, the position coordinates can be calculated when distance information is acquired for three or more times.

Subsequently, the local coordinate calculation unit 230 calculates the reliability of the calculated position coordinates of each transmitter (step S612). As the reliability, a function including the calculated differential fluctuation amount f of the transmitter position, the norm g of the difference between the calculation result of the distance between the transmitter and the transmission / reception terminal 10 and the measurement result, and the like are used. In the local region where the local region ID is 0, the differential fluctuation amount f of the transmitter #i is expressed by the following equation (3), and the calculation result and the measurement result of the distance between the transmitter #i and the transmission / reception terminal 10 are as follows. The norm g of the difference is expressed by the following formula (4).

Further, in the local region where the local region ID is 0, the likelihood w0_i of the transmitter i is expressed by the following equation (5) using the differential fluctuation amount f and the norm g.

In Expression (5), α and β are predetermined weighting factors, and assume values of 0 or more. At this time, in the local region whose local region ID is j, the reliability Wj indicating the accuracy index of the entire calculated position coordinate is calculated. As the reliability Wj, for example, the product of the likelihoods of the calculated position coordinates of the three representative transmitters for setting the coordinate system in the local region whose local region ID is j is obtained by the following equation (6). May be.

  The calculated reliability of the local area and the reliability of the transmitter position coordinates are associated with the local area ID of the local area, and are additionally stored in the local coordinate table 222 (step S613), and the flow ends.

  In the example illustrated in FIG. 13, three transmitters # 0 to # 2 are illustrated on the local area where the local area ID is 0. The position coordinates (X00, Y00) of the transmitter # 0 whose transmitter ID is 0 is calculated from the simultaneous equations of the equation (2). Further, the reliability w0_0 of the position coordinate of the transmitter # 0 is calculated from the equation (5). Similarly, the position coordinate (X01, Y01) of the transmitter # 1 whose transmitter ID is 1 is calculated from the simultaneous equations of the equation (2), and the reliability w0_1 of the position coordinate of the transmitter # 1 is expressed by the equation (2). 5) is calculated. The position coordinate (X02, Y02) of the transmitter # 2 whose transmitter ID is 2 is also calculated from the simultaneous equations of the equation (2), and the reliability w0_1 of the position coordinate of the transmitter # 2 is calculated from the equation (5). Is done.

  In the above equation, the differential fluctuation amount f and the norm g of the difference between the calculation result and the measurement result are obtained for the position coordinates of the transmitter, and the reliability of the position coordinates of the transmitter is obtained based on this. However, the differential fluctuation amount f and the norm g of the difference between the calculation result and the measurement result may be calculated for the inter-transmitter distance described later.

  In step S615, not all data stored in the measurement distance table may be deleted, but only some data may be deleted.

  For example, a predetermined number of data for newer measurement times may be left and other data may be deleted. Alternatively, an evaluation value may be assigned to each data by a predetermined method, and the data may be deleted in order from the lowest evaluation value. Moreover, you may complete | finish the process of the local coordinate calculation part 230, without deleting data.

  Next, the process performed in the local coordinate integration unit 240 will be described.

FIG. 8 is a flowchart showing details of processing executed by the integrated region extraction unit 241. The process shown in FIG. 8 corresponds to the process of step S506 in FIG.
First, the integrated region extraction unit 241 acquires information of the local coordinate table 222 (step S801). The integrated region extraction unit 241 generates all combinations for selecting two local regions from the local regions stored in the local coordinate table 222 (step S802). The integrated area extraction unit 241 selects one combination (first ID and second ID) from the generated combinations (step S803).

  The integrated region extraction unit 241 calculates the number of transmitters included in both of the two selected local regions (step S804). Then, the integrated region extraction unit 241 determines whether or not the number of transmitters (sensors) shared by the two local regions is equal to or greater than a predetermined threshold (step S805). When a transmitter having a predetermined threshold value or more is shared by two local areas (Yes in step S805), it is determined that these two areas can be integrated and set in the local coordinate table 222 as areas that can be integrated with each other. Is done. That is, in the local coordinate table 222, the second ID is stored as the “integrable region ID” corresponding to the first ID, and conversely, the second ID is stored as the “integrable region ID” corresponding to the second ID. One ID is stored.

  Next, the integrated region extraction unit 241 determines whether or not the processing in steps S803 to S806 has been performed for all the combinations generated in step S802 (step S807). If there is a combination that has not yet been processed in steps S803 to S806 (No in step S807), the process returns to step S803 to select another combination, and the subsequent processing is repeated. On the other hand, if the processing has been completed for all combinations (Yes in step S807), the integrated region extraction result is transmitted to the local coordinate table 222, and the flow is terminated. In addition, the integrated region extraction unit 241 generates a list of local regions that can be integrated with the local region (integration target list) for each local region, and transmits the list to the integration processing unit 242.

  When the integrated region extraction unit 241 extracts local regions that can be integrated, the integration processing unit 242 performs integration processing. The integration processing unit 242 generates a measurement sensor list for each local region that can be integrated with respect to one local region (target region) (FIG. 9), and integrates the target region and other target regions that can be integrated with the target region. The measurement sensors included in both of the areas are detected and associated (FIG. 10), and the correction value of the transmitter position coordinates included in the measurement sensor list is calculated (FIG. 11).

  FIG. 9 is a flowchart illustrating details of the measurement sensor list generation process executed by the integration processing unit 242.

  When the integration processing unit 242 receives the extraction result of the integration region from the integration region extraction unit 241 (step S901), the integration processing unit 242 selects an integration region that can be integrated with the target region from the integration target list for one local region (target region). A local region ID of one region is selected (step S902).

  The integration processing unit 242 selects one measurement sensor from the measurement sensors (transmitters) included in the selected integration region (step S903), and the ID of the selected measurement sensor is the measurement of the selected target region. It is determined whether it is included in the sensor list (step S904).

  If the ID of the selected measurement sensor is included in the measurement sensor list (Yes in step S904), the process proceeds to step S906. On the other hand, when the ID of the selected measurement sensor is not included in the measurement sensor list (No in step S904), the integration processing unit 242 adds the ID of the measurement sensor to the measurement sensor list (step S905).

  The integrated control unit 242 determines whether or not the processing in steps S903 to S905 has been completed for all the measurement sensors included in the selected local region (step S906). If there is a measurement sensor that has not yet been subjected to the processes of steps S903 to S905 (No in step S906), the process returns to step S903 to select a measurement sensor, and the subsequent processes are repeated. On the other hand, if the processing has been completed for all measurement sensors (Yes in step S906), the integration processing unit 242 determines whether the processing in steps S902 to S906 has been completed for all integration regions that can be integrated with the target region. Is determined (step S907).

  If there is a local region for which the processing of steps S903 to S906 has not yet been performed (No in step S907), the process returns to step S902 to select another local region, and the subsequent processing is repeated. On the other hand, if the processing has been completed for all integrated regions that can be integrated with the target region (Yes in step S907), the flow ends.

  As described above, a list (measurement sensor list) of measurement sensors (transmitters) included in a local region that can be integrated with respect to one local region is generated by the processing illustrated in FIG.

Next, processing performed by the integration processing unit 242 will be described with reference to FIGS.
FIG. 10 is a flowchart illustrating details of the sensor association process executed by the integration processing unit 242.
When the measurement sensor list for the target region is generated, the integration processing unit 242 selects one measurement sensor (transmitter) from the measurement sensor list (step S1002).

  Next, the integration processing unit 242 selects one local area from the M local areas stored in the local area table 222 (Step S1003), and the measurement sensor included in the selected local area is selected in Step S1002. It is determined whether or not it matches the measured sensor (step S1004).

  When the measurement sensor included in the selected local region does not match the selected measurement sensor (No in step S1004), the process proceeds to step S1005. On the other hand, when the measurement sensor included in the selected local region matches the selected measurement sensor (Yes in step S1004), the measurement sensors are associated (step S1005). In the association of measurement sensors, all measurement sensors included in the selected local area are assumed to be other measurement sensors in the same area as the selected measurement sensor, and the transmitter IDs of these other measurement sensors The transmitter ID of the selected measurement sensor is associated and stored in the local coordinate table 222.

  The integration processing unit 242 determines whether or not the processing in steps S1003 to S1005 has been completed for all M local regions included in the local coordinate table 222 (step S1006). If there is a local region that has not been subjected to the processes of steps S1003 to S1005 (No in step S1006), the process returns to step S1003 to select a local region, and the subsequent processing is repeated. On the other hand, if the processing has been completed for all local regions (Yes in step S1006), the integration processing unit 242 determines whether the processing in steps S1002 to S1006 has been completed for all transmitters included in the measurement sensor list. Is determined (step S1007).

  If there is a transmitter that has not been subjected to the processes of steps S1002 to S1006 (No in step S1007), the process returns to step S1002, selects another transmitter, and the subsequent processes are repeated. On the other hand, if the processing has been completed for all transmitters (Yes in step S1007), the flow ends.

  As described above, a transmitter (measurement sensor) is associated between a plurality of local regions by the process shown in FIG.

FIG. 11 is a flowchart showing details of the sensor position coordinate correction process on the reference coordinate system executed by the integration processing unit 242. The initial position of each sensor is assumed to be a value calculated by the local coordinate calculation unit 230 for a sensor on a local region set in the reference coordinate system, and given to a random number for other sensors.
The integration processing unit 242 sets a reference coordinate system from the reference local coordinates stored in the local coordinate table 222 (step S1100). The reference coordinate system may be determined in advance according to a setting operation by the user, and the setting information is stored in the reference area information storage unit 223 of the data storage unit 220. In the following, for the sake of explanation, it is assumed that a region having a local region ID of 0 is a reference region that gives a reference coordinate system. The integration processing unit 242 selects one measurement sensor (transmitter #i) from the measurement sensor list generated for the target area constituting the reference coordinate system (step S1101). Then, the integration processing unit 242 sets a set of other transmitters (set in the process of FIG. 10) in the same local area as the selected transmitter #i as a transmitter set gi according to the following equation (7). Then, the corrected coordinate value ΔXi of the calculated position of the selected transmitter #i is calculated.

In Expression (7), L _ij represents the distance between the transmitter #i and the transmitter #j.

  The integration processing unit 242 determines whether or not the processing in steps S1101 to S1102 has been completed for all transmitters in the measurement sensor list (step S1103). If there is a transmitter that has not been subjected to the processes of steps S1101 to S1102 (No in step S1103), the process returns to step S1101 to select another transmitter, and the subsequent processes are repeated.

When the processing is completed for all transmitters (Yes in step S1103), the integration processing unit 242 obtains the value of the evaluation formula J from the following formula (8), and determines whether the value is smaller than a predetermined threshold value. Determination is made (step S1104).

  In Expression (8), G represents a set of combinations of two transmitters for which the distance between transmitters is required, as will be described later.

  If the value of the evaluation formula J is smaller than the threshold value (Yes in step S1104), the flow ends. On the other hand, if the value of the evaluation formula J is equal to or greater than the predetermined threshold (No in step S1104), it is determined that all transmitters included in the measurement sensor list are not selected (step S1105), and the process returns to step S1101 and the measurement sensor again. Select a transmitter from the list and repeat the subsequent processing.

  As described above, the correction value of the position coordinate of the transmitter included in the measurement sensor list generated for the target region can be obtained by the process shown in FIG.

  9 to 11 may be executed continuously for one target area, but may be executed individually for different local areas.

  In addition, the inter-transmitter distance calculation shown in FIG. 12 may be performed within a local area that is determined to be able to be integrated with another local area.

  FIG. 12 is a flowchart showing details of the inter-transmitter distance calculation processing executed by the integration processing unit 242.

  The integration processing unit 242 acquires the extraction result by the integrated region extraction unit 214 illustrated in FIG. 8 and the information of the local coordinate table 222 (step S1201). The integration processing unit 214 determines whether or not the integrated region extraction unit 241 has extracted a local region that can be integrated with another local region (step S1202). If there is no local area that can be integrated (No in step S1202), the process ends.

  On the other hand, when there is a local region that can be integrated (Yes in step S1202), the integration processing unit 242 selects one local region from unselectable integration possible regions (step S1203). The integration processing unit 242 determines whether or not there is a combination of transmitters for which the inter-transmitter distance is not calculated in the selected local region (step S1204).

  If there is no combination of transmitters for which the inter-transmitter distance is not calculated (No in step S1204), the process returns to step S1202, and the subsequent processing is repeated. On the other hand, if there is a combination of transmitters for which the distance between transmitters has not been calculated (Yes in step S1204), the integration processing unit 242 selects a combination of unselected transmitters (step S1205). Then, for the selected combination of transmitters, the inter-transmitter distance and its reliability are calculated (step S1206), and the process returns to step S1204. The calculated inter-transmitter distance and its reliability are stored in the local coordinate table 222.

The inter-transmitter distance is calculated in each local region, and is calculated using the position coordinates of the transmitter stored in the local coordinate table 222. For example, in the example illustrated in FIG. 13, the position coordinates and reliability of the three transmitters # 0 to # 2 included in the local area whose local area ID is 0 are calculated and stored in the local coordinate table 222. Yes. In this case, the distance L0_01 between the transmitter # 0 having the calculated position coordinates (X00, Y00) and the transmitter # 1 having the calculated position coordinates (X01, Y01) is expressed by the following equation (9). Is calculated from

In addition, the reliability w0_01 of the distance between transmitters calculated in this way is given by a product of the reliability w0_0 and w0_1 of the position coordinates of each transmitter, as shown in Expression (10), for example.

  In the example of the three transmitters # 0 to # 2 shown in FIG. 13, as shown in FIG. 14, the distance L0_12 between the transmitter # 1 and the transmitter # 2, and the transmitter # 2 and the transmitter # 0 The distance L0_20 between is also calculated in the same manner as the equation (9). Further, the reliability w0_12 of the inter-transmitter distance L0_12 and the reliability w0_20 of the inter-transmitter distance L0_20 are also calculated in the same manner as in the equation (10).

  As described above, according to the processing of FIG. 12, it is possible to calculate the distance between transmitters in the local region and the reliability thereof.

  The processing shown in FIGS. 9 to 12 can calculate the position coordinates of each transmitter in the local region and the reliability thereof, and the distance between the transmitters and the reliability thereof.

  It should be noted that the transmission engine distance calculation result varies depending on the local region. In FIG. 15, a local region whose local region ID is 0 and a local region whose local region ID is 1 are shown. In the example of FIG. 15, the transmitter-to-transmitter distance L0_12 between the transmitter # 1 and the transmitter # 2 calculated in the local region where the local region ID is 0, and the transmission calculated in the local region where the local region ID is 1 The size of the inter-transmitter distance L1_12 between the machine # 1 and the transmitter # 2 is different. Thus, it is considered that the distance between transmitters and the reliability thereof vary depending on the local region.

The distance between the transmitters may be calculated using a weighted average of the distances between the transmitters weighted by the reliability in order to reduce the influence of the distance between the transmitters having low reliability. In the example shown in FIG. 15, the transmitter distance L ₁₂ of the transmitter # 1 and transmitter # 2, which is calculated using the reliability is given by the following equation (11).

  Thereby, the distance between transmitters can be calculated using data with high reliability preferentially.

  Next, the integration processing unit 242 integrates all local regions on the undirected graph into the reference coordinate system using the weighted average of the distances between the transmitters (step S2003). That is, the position coordinate in the reference coordinate system of each transmitter is calculated.

  FIG. 17 is a diagram showing the distance between the transmitters shown in FIG. 16 by the weighted average distance between the transmitters. The position coordinate X0_i of the transmitter #i on the reference coordinate system is calculated by performing an optimal calculation that minimizes the value J of the evaluation formula given by the formula (8). In equation (8), a set G represents a set of transmitter combinations for which the inter-transmitter distance is calculated. An example of an algorithm for minimizing the value J of the evaluation equation is a method of correcting the position coordinates of each transmitter using the correction value obtained from Equation (7). The integration processing unit 242 performs recursive calculation according to Expression (8) until the value J of the evaluation expression becomes equal to or less than the threshold value.

  For example, in the example shown in FIG. 17, the set g2 of transmitters for which the inter-transmitter distance is calculated with the transmitter # 2 is g2 = {0, 1, 3, 4, 5}. The integration processing unit 242 determines the position coordinates of the transmitter # 2 based on the difference between the calculated position coordinates of the transmitter # 2 and the weighted average distance between each transmitter included in the set g2 and the transmitter # 2. Correct the position coordinates of transmitter # 2.

  FIG. 18 is a diagram illustrating how the position coordinates of transmitter # 2 are corrected. For example, when the position of transmitter # 2 is corrected using the estimated calculation position of transmitter # 0, the distance between transmitters calculated from the estimated positions of both transmitters is calculated, and the value of the calculated distance between transmitters is calculated. And the difference in the distance between transmitters weighted by the reliability (hereinafter, the difference is assumed to be n). When the value of n is positive, the position coordinates of the point where the transmitter # 2 is moved by the amount of n in the opposite direction to the transmitter # 0 on the straight line connecting the estimated positions of the two transmitters are Let 2 be the corrected position coordinates. When the value of n is negative, the position coordinate of the point where the transmitter # 2 is moved by the amount n toward the transmitter # 0 on the straight line is set as the corrected position coordinate of the transmitter # 2. Similarly, the position coordinates of the transmitter # 2 are corrected using the position coordinates of the transmitter # 2 and the position coordinates of other transmitters (transmitters # 1, # 3 to # 5) that have measured the distance.

  With the above processing, the position coordinates of each transmitter in the reference coordinate system are calculated.

The integration processing unit 424 also calculates the position coordinates of the transmission / reception terminal 10 (step S2004). The position coordinates of the transmission / reception terminal 10 are calculated by solving simultaneous equations generated by the measured distance between the calculated position coordinates of the transmitter #i and the transmission / reception terminal 10. For example, when the transmission / reception terminal 10 performs distance measurement with the transmitters # 0 to # 2, the position coordinates of the transmission / reception terminal 10 are calculated from the following simultaneous equations (12).

  As described above, the position coordinates of each transmitter and the transmission / reception terminal 10 in the reference coordinate system can be calculated.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention when it is practiced. Further, each of the embodiments includes inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in one embodiment or the constituent elements shown in some embodiments are combined, they are described in the column of the problem to be solved by the invention. In the case where the problems described above can be solved and the effects described in the “Effects of the Invention” can be obtained, a configuration in which these constituent requirements are deleted or combined can be extracted as an invention.

  DESCRIPTION OF SYMBOLS 10 ... Transmission / reception terminal, 20 ... Position calculation apparatus, 101 ... Reception part, 102 ... Distance measurement part, 103 ... Transmission part, 210 ... Reception part, 220 ... Data storage part, 221 ... Local coordinate table, 2223 ... Reference area information storage , 240 ... local coordinate integration unit, 241 ... integrated region extraction unit, 242 ... integration processing unit, 243 ... input / output unit.

Claims (3)

In an environment including a plurality of sensors, a position calculation device that receives distance information between a terminal that can move in the environment and each of the plurality of sensors, and calculates the position coordinates of the terminal,
A plurality of local regions each composed of a plurality of sensors are detected, and the positions of the plurality of sensors constituting the local region in each of the local regions based on the distance between the terminal and each of the plurality of sensors. First coordinate calculation means for calculating coordinates;
An integrated region extraction means for extracting two or more local regions sharing a predetermined number of sensors among the plurality of local regions as regions that can be integrated with each other;
In each of the two or more local regions extracted as areas that can be integrated, the inter-sensor distance and the reliability of the inter-sensor distance are calculated, and the reliability of the inter-sensor distance calculated in each of the two or more local regions To calculate the inter-sensor distance after weight correction, and to calculate the position coordinates of each sensor in a coordinate system in which the two or more local regions are integrated based on the corrected inter-sensor distance. Coordinate calculation means of
A position calculation device comprising: A position calculation device including a first coordinate calculation unit, an integrated region extraction unit, and a second coordinate calculation unit, and in an environment including a plurality of sensors, a terminal that can move in the environment and the plurality of sensors, respectively A position calculation method used in a position calculation device that receives distance information between the terminal and calculates the position coordinates of the terminal,
The first coordinate calculation means detects a plurality of local regions each composed of a plurality of sensors, and based on the distance between the terminal and each of the plurality of sensors, in each of the local regions, Calculate the position coordinates of a plurality of sensors constituting the local region,
The integrated region extracting means extracts two or more local regions sharing a predetermined number of sensors from the plurality of local regions as regions that can be integrated with each other,
The second coordinate calculation means calculates the inter-sensor distance and the reliability of the inter-sensor distance in each of the two or more local areas extracted as the areas that can be integrated, and in each of the two or more local areas In a coordinate system in which weighting is performed according to the calculated reliability of the distance between sensors, the distance between sensors after weight correction is calculated, and the two or more local regions are integrated based on the distance between sensors after the correction. A position calculation method for calculating the position coordinates of each sensor. In an environment including a plurality of sensors, a computer used for a position calculation device that receives distance information between each of the plurality of sensors and a terminal that can move within the environment, and calculates a position coordinate of the terminal,
A plurality of local regions each composed of a plurality of sensors are detected, and the positions of the plurality of sensors constituting the local region in each of the local regions based on the distance between the terminal and each of the plurality of sensors. First coordinate calculating means for calculating coordinates;
An integrated region extracting means for extracting two or more local regions sharing a predetermined number of sensors among the plurality of local regions as regions that can be integrated with each other;
In each of the two or more local regions extracted as areas that can be integrated, the inter-sensor distance and the reliability of the inter-sensor distance are calculated, and the reliability of the inter-sensor distance calculated in each of the two or more local regions To calculate the inter-sensor distance after the weight correction, and calculate the position coordinates of each sensor in the coordinate system in which the two or more local regions are integrated, based on the inter-sensor distance after the weight correction. The position calculation program for functioning as 2 coordinate calculation means.

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