JP2010130520A - System and method of managing database, system and method of detecting reception environment change - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately update a database for holding information that is used for positioning mobile communication terminals and indicates the relationship between reception strength and positions of radio waves. <P>SOLUTION: A positioning server 10 manages a database 11 for positioning that is used for positioning a cellular terminal (mobile communication terminal) 20 and holds information indicating a relationship between reception strength and positions of radio waves according to a cellular base station 30. The positioning server 10 includes: a strength information reception section 12 for receiving strength information indicating reception strength of radio waves that is received by the cellular terminal 20 and indicates reception strength of radio waves according to the cellular base station 30; a position information reception section 13 for receiving position information indicating the position, where the radio waves are received by the cellular terminal 20; an environment change detection section 14 for detecting a temporal change in a reception environment of radio waves, based on the received strength information; and an update section 16 for updating the database 11 for positioning according to the detected change. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a database management system and a database management method for managing a database that holds information indicating the relationship between radio wave reception intensity and position, which is used for positioning of a mobile communication terminal, and a reception environment having characteristics common to them. The present invention relates to a change detection system and a reception environment change detection method.

Conventionally, techniques for estimating the position of a mobile communication terminal based on the reception intensity (reception level) of radio waves received by the mobile communication terminal have been proposed. In Patent Document 1, information indicating the relationship between the reception intensity of a radio wave received from a predetermined base station and the position where the radio wave is received is stored in a database, and matching with the reception intensity is performed using the database. And a technique for estimating the position of the mobile communication terminal.
JP-A-7-231473

  With the method described in Patent Document 1, if the information indicating the above relationship stored in the database is not appropriate information, the position of the mobile communication terminal cannot be estimated accurately. For example, if the location where the base station, which is the source of radio waves, is installed, or if the propagation environment changes due to the construction of the building, etc. The position of a mobile communication terminal cannot be estimated.

  The present invention has been made in view of the above, and is a database management system capable of appropriately updating a database used for positioning of a mobile communication terminal and holding information indicating the relationship between radio wave reception intensity and position It is another object of the present invention to provide a reception environment change detection system and a reception environment change detection method that have features common to the database management method.

  In order to achieve the above object, a database management system according to the present invention is a database that holds information indicating the relationship between the reception intensity and position of a radio wave according to a radio wave transmission source, which is used for positioning of a mobile communication terminal. Is a database management system for managing intensity information receiving means for receiving intensity information indicating reception intensity of radio waves according to a transmission source received or transmitted by a mobile communication terminal, and received by an intensity information receiving means. Position information receiving means for receiving position information indicating the position where the radio wave is received or transmitted by the mobile communication terminal related to the intensity information, and the radio wave received or transmitted at the first time received by the intensity information receiving means. Received or transmitted at the second time in the vicinity of the position corresponding to the first received strength information and the first received strength information. Environment change detection means for comparing the second reception intensity information of the received radio wave and detecting that there is a temporal change in the radio wave reception environment at the mobile communication terminal at the location based on the comparison result And updating means for updating the database in accordance with the change detected by the environment change detecting means based on the intensity information received by the intensity information receiving means and the position information received by the position information receiving means. It is characterized by.

  In the database management system according to the present invention, the strength information indicating the reception strength according to the transmission source received or transmitted by the mobile communication terminal is received, and the position where the radio wave is received or transmitted by the mobile communication terminal is determined. The indicated position information is received. Subsequently, in the database management system, the above change is detected from the information on the first reception intensity at the first time and the information on the second reception intensity at the second time at positions close to each other. The database is updated as changes occur. As described above, according to the present invention, since the database is updated based on the temporal change in the radio wave reception environment, the database can be appropriately updated.

  It is desirable that the environment change detection means divides the region that is the detection target of the change into a grid, and sets the position in the same grid as the vicinity. According to this configuration, positions that are close to each other can be easily determined, and thus the present invention can be easily implemented in that respect.

  It is desirable that the first time and the second time are included in a first time zone and a second time zone each having a predetermined time interval. According to this configuration, a predetermined time interval can be provided between the first time and the second time, and the temporal change according to the time interval can be detected. As a result, the database can be appropriately updated based on the above temporal change corresponding to the time interval.

  It is desirable that at least one of the first reception strength information and the second reception strength information is plural. According to this configuration, since the temporal change can be detected based on a plurality of information, the temporal change can be appropriately detected. As a result, the database can be updated more appropriately.

  As a comparison, it is desirable that the environmental change detection means take a difference between the average of the reception strength related to the information of the first reception strength and the average of the reception strength related to the information of the second reception strength. According to this configuration, the temporal change can be detected reliably and appropriately. As a result, the database can be updated reliably and appropriately.

  The update means desirably updates the database so that the greater the change detected by the environment change detection means, the less the influence of the information before update. According to this configuration, it is possible to perform an appropriate database update according to the temporal change.

  By the way, the present invention can be described as a database management method as described below, in addition to the database management system as described above. This is substantially the same invention only in different categories, and has the same operations and effects.

  That is, the database management method according to the present invention is a database management method for managing a database used for positioning of a mobile communication terminal and holding information indicating the relationship between the reception intensity and position of the radio wave according to the radio wave source. The strength information receiving step for receiving the strength information indicating the received strength of the radio wave corresponding to the transmission source received or transmitted by the mobile communication terminal, and the movement related to the strength information received in the strength information receiving step A position information receiving step for receiving position information indicating a position where a radio wave is received or transmitted by the communication terminal, and a first reception intensity of the radio wave received or transmitted at the first time received in the intensity information receiving step. Of the radio wave received or transmitted at the second time in the vicinity of the position corresponding to the information of the first reception intensity An environment change detection step for detecting that there is a temporal change in the radio wave reception environment in the mobile communication terminal at the position based on the comparison result, and an intensity information reception step And updating the database in accordance with the change detected in the environmental change detection step based on the intensity information received in step S1 and the position information received in the step of receiving position information.

  Further, the above-described features of the present invention relating to the detection of temporal changes in the radio wave reception environment in the mobile communication terminal are novel features by themselves, and the reception environment change detection system and the reception environment change detection are as follows. It can be described as a method invention.

  That is, the reception environment change detection system according to the present invention includes intensity information receiving means for receiving intensity information indicating reception intensity of radio waves according to a radio wave transmission source received or transmitted by a mobile communication terminal, and intensity information. Position information receiving means for receiving position information indicating the position where radio waves are received or transmitted by the mobile communication terminal related to the intensity information received by the receiving means, and reception at the first time received by the intensity information receiving means Alternatively, information on the first reception intensity of the transmitted radio wave and information on the second reception intensity of the radio wave received or transmitted at the second time in the vicinity of the position corresponding to the information on the first reception intensity. Environment change detection means for detecting that there is a temporal change in the radio wave reception environment at the mobile communication terminal at the location based on the comparison result, And output means for outputting information indicating the change detected by the change detecting means, characterized in that it comprises a.

In addition, the reception environment change detection method according to the present invention includes an intensity information reception step of receiving intensity information indicating reception intensity of a radio wave received or transmitted by a mobile communication terminal according to a radio wave source, and intensity information. A position information receiving step for receiving position information indicating a position where radio waves are received or transmitted by the mobile communication terminal related to the strength information received in the receiving step, and a reception at the first time received in the strength information receiving step. Alternatively, information on the first reception intensity of the transmitted radio wave and information on the second reception intensity of the radio wave received or transmitted at the second time in the vicinity of the position corresponding to the information on the first reception intensity. Environment change detection that detects that there is a temporal change in the radio wave reception environment at the mobile communication terminal at the location based on the comparison result. A step, an output step for outputting information indicating the detected change in the environment change detecting step,
It is characterized by including.

  According to the reception environment change detection system and the reception environment change detection method according to the present invention, it is possible to detect temporal changes in the reception environment of radio waves in the mobile communication terminal.

  According to the present invention, the database used for positioning of the mobile communication terminal, which holds information indicating the relationship between radio wave reception intensity and position, is updated based on temporal changes in the radio wave reception environment. The database can be updated appropriately.

  Hereinafter, preferred embodiments of a database management system and a database management method according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 shows a positioning server 10 which is a database management system according to this embodiment. The positioning server 10 is a device that estimates the position of the cellular terminal (mobile communication terminal) 20. The positioning of the cellular terminal 20 by the positioning server 10 is performed using a framework of a cellular communication system (mobile communication system). Specifically, it is performed based on the reception intensity (reception level) of the radio wave transmitted from the cellular base station 30 and received by the cellular terminal 20. From the information indicating the reception intensity, the positioning database 11 that holds information indicating the relationship between the reception level and the position of the radio wave corresponding to the cellular base station 30 is referred to, and matching processing is performed to determine the position of the cellular terminal 20. Presumed. The positioning server 10 can transmit / receive information to / from the cellular terminal 20 via the cellular base station 30 or the like. Note that the positioning server 10 may be included in the mobile communication network.

  The cellular terminal 20 is a mobile communication terminal that can perform mobile communication. The cellular terminal 20 performs wireless communication with the cellular base station 30. That is, the cellular terminal 20 transmits and receives radio waves to and from the cellular base station 30. The cellular terminal 20 measures the reception intensity of the radio wave received from the cellular base station 30 and transmits the information (intensity information) to the positioning server 10 for the positioning of the terminal 20 itself. The intensity information transmitted from the cellular terminal 20 to the positioning server 10 is associated with information (for example, a base station ID) specifying the cellular base station 30 that has transmitted the radio wave, and the information is also transmitted. Is done. Further, the cellular terminal 20 may measure the RTT (Round Trip Time) of the radio wave and transmit it together with the intensity information.

  The intensity information transmitted from the cellular terminal 20 to the positioning server 10 is also used for updating the positioning database 11. Further, the strength information may be transmitted from the cellular terminal 20 to the positioning server 10 only for updating the positioning database 11. The cellular terminal 20 also has a GPS positioning function for receiving radio waves from a GPS (Global Positioning System) satellite 40 and positioning the terminal 20 based on the radio waves. When the GPS positioning is successful, the cellular terminal 20 acquires position information (for example, latitude and longitude information) indicating the position of the terminal 20 as a positioning result, and information (for example, error radius) indicating the accuracy of positioning. To do. When the cellular terminal 20 transmits intensity information to the positioning server 10 for updating the positioning database 11, the cellular terminal 20 also transmits information obtained by GPS positioning at the position where the intensity information is acquired to the positioning server 10. In addition, when GPS positioning fails, the information to that effect is transmitted. In addition, when the altitude (altitude) can be acquired by GPS positioning, the information may also be included in the position information. Transmission of information obtained by GPS positioning may be transmitted together with intensity information, or may be performed in response to a request from the positioning server 10 as will be described later (in this case, not only transmission but GPS The positioning itself may also be performed in response to a request from the positioning server 10).

  When the cellular terminal 20 transmits intensity information and information obtained by GPS positioning to the positioning server 10 for updating the positioning database 11 as described above, the cellular terminal 20 associates them with each other, for example, MR (measurement report) ). Further, when measuring the strength information, the cellular terminal 20 also acquires time information indicating the time at that time (for example, by a timer built in the cellular terminal 20), and positioning the time information together. Send to server 10. The transmission of these pieces of information from the cellular terminal 20 to the positioning server 10 is performed according to a periodic request (for example, a request for GPS positioning) from the positioning server 10 as described later, for example. Is called. Further, the cellular terminal 20 may voluntarily perform periodic transmission to the positioning server 10.

  Note that it is not necessary for all the cellular terminals 20 that are positioning targets of the positioning server 10 to have a GPS positioning function, and only the cellular terminals 20 that transmit information for updating the positioning database 11 have a GPS positioning function. What is necessary is just to be provided. There may be a cellular terminal 21 for updating the positioning database 11 that is not a positioning target of the positioning server 10. The cellular terminal 21 for updating the positioning database 11 is, for example, an in-vehicle communication terminal as shown in FIG. 1, and corrects the position information measured by the GPS positioning function using a car navigation technology or the like and has high accuracy. The position information (calibration data) of the terminal 21 can be acquired. The cellular terminal 21 for updating the positioning database 11 also transmits the strength information and the position information to the positioning server 10 in the same manner as the cellular terminal 20 described above. The cellular terminals 20 and 21 include hardware such as a CPU (Central Processing Unit), a memory, and a wireless communication module.

  Each cellular base station 30 is a component in the mobile communication network, but is a radio wave source that transmits radio waves for performing the above-described positioning, and is installed with its position determined in advance. Each cellular base station 30 is set with information for uniquely identifying the cellular base station 30 such as a base station ID, and the positioning server 10 and the cellular terminal 20 are based on the information. Can be specified. The cellular base station 30 includes hardware such as a CPU, a memory, and a wireless communication module.

  Subsequently, the functional configuration of the positioning server 10 will be described. As shown in FIG. 1, the positioning server 10 includes a positioning database 11, an intensity information receiving unit 12, a position information receiving unit 13, an environment change detecting unit 14, and an updating unit 16. The above constituent elements are constituent elements as a database management system according to the present invention. In addition to the above constituent elements, means for performing positioning processing using the positioning database 11 and positioning the cellular terminal 20 are also provided. ing.

  As described above, the positioning database 11 is used for positioning of the cellular terminal 20 and indicates information indicating the relationship between the radio wave reception intensity at the cellular terminal 20 corresponding to the cellular base station 30 and the position of the cellular terminal 20. It is a database to keep. Specifically, the positioning database 11 holds the above information by storing data in the table shown in FIG.

  As shown in FIG. 2, the positioning database 11 stores data for each pattern of radio wave reception intensity received by the cellular terminal 20 at a predetermined position. For one pattern, data of reception intensity for each of up to n cellular base stations 30 is stored as information of reception intensity ("base station-1" to "base station-n" data in the figure). . The data of each cellular base station 30 includes base station ID (data such as “ID-1-1” in the figure), data indicating reception intensity (data such as “LV-1-1” in the figure), and RTT. Is composed of three pieces of data (data such as “RTT-1-1” in the figure). That is, the cellular base station 30 (data) for each pattern (the combination of the cellular base stations 30 can be different for each pattern).

  The stored data such as signal strength may be data of a predetermined number of digits, for example. For example, if the number of digits after the decimal point is rounded down, 200.367 dBm is set to 20.3 dBm (the number of digits to be truncated can be set to an arbitrary number). Moreover, it is good also as data with a fixed width | variety. For example, when the reception strength is 50 to 60 dBm, the data stored in the table is “1”, when the reception strength is 40 to 50 dBm, the data stored in the table is “2”, and the reception strength is 30 to 40 dBm. The data stored in the table may be “3”. The above patterning may be similarly performed on data other than signal strength. Further, when the number of the cellular base stations 30 in one pattern is less than n, nothing may be stored in the data in that portion (empty).

  The data of each pattern includes position coordinate data (data such as “Pos-1” in the figure), accuracy data (data such as “Acc-1” in the figure), and time stamp as position information. Data (data such as “T-1” in the figure), update count data (data such as “N-1” in the figure), and height data (data such as “H-1” in the figure) ) Are stored in association with each other. The position coordinate data is position data that is estimated as the location of the cellular terminal 20 when the signal intensity of the radio wave received by the cellular terminal 20 is the reception intensity of the corresponding pattern. Specifically, the position coordinate data is the same data as the position information (for example, latitude and longitude information) acquired by the GPS positioning function of the cellular terminal 20.

  The accuracy data is data indicating the accuracy of the position of the cellular terminal 20 estimated from the position coordinates. Specifically, the accuracy data (for example, error information acquired by the GPS positioning function of the cellular terminal 20). Radius) is the same data. The time stamp data is data indicating the (latest) past time when the corresponding pattern data (position coordinates, accuracy, etc.) is updated. The update count data is data indicating the number of times the corresponding pattern data (position coordinates, accuracy, etc.) has been updated. The height data is altitude (elevation) data corresponding to the position coordinates, and is similar to the information acquired by the GPS positioning function of the cellular terminal 20.

  The positioning server 10 receives from the cellular terminal 20 intensity information (radiation intensity pattern) indicating the reception intensity of the radio wave corresponding to the cellular base station 30, and the information and the radio wave stored in the positioning database 11. The position of the cellular terminal 20 is estimated by matching with the intensity pattern. The above matching is performed in the same manner as a conventional positioning technique using a database such as the positioning database 11.

  The strength information receiving unit 12 is strength information receiving means for receiving, from the cellular terminal 20, strength information (radio wave strength pattern) received by the cellular terminal 20 and indicating the received strength of the radio wave according to the cellular base station 30. . The radio field intensity pattern is, for example, information in which one or more base station IDs and reception intensity are associated with each other. The strength information receiving unit 12 receives time information indicating the time when the strength information is measured from the cellular terminal 20 together with the strength information. The strength information receiving unit 12 outputs the received strength information and time information to the updating unit 16. Further, the intensity information receiving unit 12 also outputs the received intensity information and time information to the environment change detecting unit 14.

  The position information receiving unit 13 is position information receiving means for receiving, from the cellular terminal 20, position information indicating the position where the cellular terminal 20 has received the radio wave related to the intensity information. The position information is obtained by positioning by the GPS positioning function of the cellular terminal 20 as described above. Further, the position information corresponds to the intensity information as described above. When the location information and the strength information are separately transmitted from the cellular terminal 20 to the positioning server 10, the positioning server 10 determines that each information is associated with each other by including the same ID. Keep it available. The position information reception unit 13 outputs the received position information to the update unit 16 and the environment change detection unit 14.

  The position information receiving unit 13 periodically makes a positioning request for GPS positioning so that the above-described information can be received from the cellular terminal 20. The positioning request is performed, for example, by transmitting a signal related to the positioning request to the cellular terminal 20 via the mobile communication network, and is continuously performed at regular time intervals T2. The cellular terminal 20 that is the target of the positioning request is, for example, a cellular terminal 20 that has a GPS positioning function located in the mobile communication network. Further, the information transmission request to the cellular terminal 20 does not necessarily have to be made by the position information receiving unit 13 and may be made from the strength information receiving unit 12 or the like.

  The environment change detection unit 14 generates a radio wave reception environment in the cellular terminal 20 from the intensity information received by the intensity information reception unit 12 and the position information received by the position information reception unit 13 corresponding to a plurality of time information. It is an environmental change detection means for detecting that there has been a change over time. Here, the temporal change in the radio wave reception environment in the cellular terminal 20 is, for example, a change in the position (time) of the location where the cellular base station 30 is installed or the strength of the radio wave transmitted from the cellular base station 30. It is caused by (temporal) change. It may also occur when there is a building around the cellular base station 30 that affects the propagation of radio waves. In the present embodiment, the above change is called a network change. The environment change detection unit 14 detects a network change for each position related to the position information. The environment change detection unit 14 detects a network change for each cellular base station 30 that is a radio wave source.

  The environment change detection unit 14 includes the first reception intensity information of the radio wave received at the first time and the first position in the vicinity of the position indicated by the position information corresponding to the intensity information of the first reception intensity. The network change is detected by comparing the information on the second reception intensity of the radio wave received at the second time different from the above time as follows. The first time and the second time are times included in the first time zone and the second time zone each having a predetermined time interval. The first time zone and the second time zone are different time zones. If this time interval is long (for example, in units of days), a long-term network change will be detected, and if it is short (for example, in units of time (h)), a short-term network change will be detected. In addition, the intensity information of the first reception intensity and the intensity information of the second reception intensity are plural as follows, and the network is changed using the statistical values such as the average values as follows. It is better to detect.

  The environment change detection unit 14 divides a region that is a detection target of a network change into grids, and sets a position in the same grid as the vicinity. As shown in FIG. 3, the environment change detection unit 14 stores an electric field map 60 for each cellular base station 30 (the electric field maps 60a, 60b, and 60c correspond to each cellular base station 30). Yes. In the electric field map shown in FIG. 3, each rectangle divided into small pieces corresponds to a grid. The electric field map is information indicating the reception intensity of the radio wave (received by the cellular terminal 20) from the cellular base station 30 at the position indicated by the grid. One grid is on the order of several m to several hundred m on a side. Note that the grid does not necessarily have to be continuous, and may be a collection of discrete regions.

  The environment change detection unit 14 specifies in which grid the position indicated by the position information received from the position information reception unit 13 is located. Based on the specification, the environment change detection unit 14 stores the strength information (for each cellular base station 30) received from the strength information receiving unit 12 in association with the grid along with the time information. In this embodiment, it is assumed that each data stored in the positioning database 11 is also in units of grids (one pattern data is associated with one grid). Each data position coordinate stored in the positioning database 11 is a position such as the center of the grid. Further, the determination of whether or not it is in the vicinity is not based on the grid as described above, and may be performed by determining whether or not the distance between the positions indicated by the position information is equal to or less than a predetermined value.

  Subsequently, the environment change detection unit 14 uses the stored intensity information for each of the grid and the cellular base station 30 to obtain two averages of the received intensity during the time T going back from the time t1 and t2 as shown in FIG. Is calculated. Here, the time t2 is a time later than the time t1, and is, for example, the time when the average value is calculated. Further, the interval between the time t2 and the time t1 corresponds to the predetermined time interval described above, and is determined in advance and stored in the environment change detection unit 14. The time T corresponds to the first time zone and the second time zone described above, and is stored in the environment change detection unit 14 in advance. Note that the average received strength does not necessarily have to be measured by the same cellular terminal 20.

Specifically, the environment change detection unit 14 uses, for example, intensity information received and stored at a predetermined timing after the request for positioning from the position information receiving unit 13 and a time T from the time point. The average of the received intensity for each grid and cellular base station 30 (radio waves received from the grid) is calculated. The environment change detection unit 14 stores the average value calculated in this way as the value L _tn for each grid and cellular base station 30 together with the latest value t _n of the received time information.

The environment change detection unit 14 compares the latest average received intensity L _tn with the previous average received intensity L _tn−1 in each grid g and each cellular base station 30 (radio waves received from). The difference DL _g is calculated using the following equation.
DL _g = | L _tn -L _tn-1 |
Here, | · | indicates an absolute value. Note that the above calculation does not necessarily have to be an absolute value of the difference, as long as the degree indicating the difference between the latest average received intensity L _tn and the previous average received intensity L _tn−1 is known. For example, the square value of the difference may be taken.

Subsequently, the environment change detection unit 14 calculates a representative DL that is an index value for determining whether or not there is a network change from the obtained difference DL _g . This calculation is performed for each cellular base station 30. The representative DL is calculated by any of the following, for example.
(1) Average value of the top x of all DL _g sizes (2) Average value of y around each of the top x grids of DL _g size (3) Average value of DL _g of all grids (4) Average of all grids within a distance d from the grid having the largest DL _g (5) Average value of grids where DL _g is greater than (DL _gmax −z) where DL _gmax is the maximum value of DL _g , x, y and z are preset as parameters and are values stored by the environment change detection unit 14.

  The environment change detection unit 14 detects a network change using the representative DL. The environment change detection unit 14 determines whether or not the representative DL is larger than the threshold value TL. When the environment change detection unit 14 determines that the representative DL is larger, the environment change detection unit 14 detects that there is a network change. The threshold value TL is set in advance and stored in the environment change detection unit 14. Note that this determination is performed for each cellular base station 30 (reception strength of radio waves from the cellular base station 30). For example, if it is determined that the representative DL is larger than the threshold TL in any one of the cellular base stations 30, the network Detect that there is a change. The environment change detection unit 14 outputs information related to the network change to the update unit 16. Information relating to the network change is used in updating by the updating unit 16.

  The updating unit 16 is an updating unit that updates the positioning database 11 based on the strength information received by the strength information receiving unit 12 and the position information received by the position information receiving unit 13. The update unit 16 performs update based on information related to the network change input from the environment change detection unit 14. First, the update unit 16 determines whether or not the information input from the environment change detection unit 14 indicates a network change, and when it is determined that the information indicates a network change, the following positioning database 11 is determined. Update processing is performed. When the update unit 16 determines that the network change is not indicated, the update unit 16 does not update the positioning database 11.

  As an update process of the positioning database 11, first, the update unit 16 specifies a range (grid) that is an update target of the database based on the information related to the network change input from the environment change detection unit 14. Specifically, for example, the grid to be updated is a grid related to the average reception level used for calculating the representative DL.

The update unit 16 determines whether the position information input from the position information receiving unit 13 is included in the grid after specifying the grid to be updated by the above processing (note that the update unit 16 also detects the environmental change). The information which shows the correspondence of a grid and a position is hold | maintained similarly to the part 14). When the update unit 16 determines that the position information input from the position information reception unit 13 is not included in the grid, the update database 16 does not update the positioning database 11. When the update unit 16 determines that the position information input from the position information receiving unit 13 is included in the grid, the update unit 16 uses the position information corresponding to the grid stored in the database of the positioning database 11 as the position information. Update based on the intensity information corresponding to. The updated strength information DB _new is calculated according to the following formula stored in advance by the updating unit 16.
DB _new = DB _old × W _g + Data _MR × (1-W _g )
Here, DB _old is the received strength before update acquired from the positioning database 11, Data _MR is the received strength related to the strength information input from the strength information receiving unit 12, and W _g is before updated. , Each of the received intensity weights (influence degree of information before update). Here, the update unit 16 determines W _g as follows.

And all W _{g =} 0 in the update range is greater than the threshold value TL ₂ representatives DL calculated at the time of detection of network changes were determined in advance. This is based on the idea that if the change in the temporal network (reception strength) is larger than a certain level, it is preferable not to use past information (appropriate information is stored earlier in the positioning database 11). Is. The threshold value TL ₂ is set to a value larger than the threshold value TL used when detecting a network change, and is stored in the update unit 16 in advance. On the other hand, if the representative DL is the threshold value TL ₂ below, the DL _g as a variable, the function value is calculated W _g by monotonically decreasing function in the range from 0 to 1. This is based on the idea that it is preferable to use past information if the change in the network is below a certain level. That is, the positioning database 11 is updated so that the degree of influence of the information before update becomes smaller as the degree of network change detected by the environment change detection unit 14 becomes larger. Here, the weight W _g is determined for each cellular base station 30 (reception strength from), and the updated reception strength is calculated for each cellular base station 30 by the above formula.

The update unit 16 stores the calculated intensity information DB _new in the positioning database 11 in place of the intensity information DB _old before update. Incidentally, for the update target outside the grid, it distinguishes update range by set as -1 or the like the weight W _g, the weight of the updated grid sets a value of 0 or more.

When a plurality of position information and intensity information are input, the update unit 16 may update the positioning database 11 a plurality of times by the same method as described above. In this case, the positioning database 11 updated as described above may be regarded as the positioning database 11 before the next update, and the above processing may be repeated a predetermined number of times. Further, Wg may be slightly increased every time the positioning database 11 is updated, such as W _g2 = W _g1 × 1.01 every time the DB is updated. Further, if W _g is larger than a predetermined threshold value Wt, the updating of the positioning database 11 may be immediately terminated. When the update of the positioning database 11 is finished, it is excluded from the update target as W _g = −1 or the like.

The above update is performed, for example, like the data shown in FIG. As shown in FIG. 5, the weight (W _gA1 , W _gB1 ,...) _Of the reception strength (BTS-A, BTS-B,...) Before update is determined for each cellular base station 30, and the strength information receiving unit 12. The updated reception strength is calculated using the above-described formula using the strength information (MR data) input from. In this calculation, values after the decimal point are rounded off. The updated reception intensity is stored in the positioning database 11 and used as the reception intensity before update at the next update.

  In the above description, it is assumed that the strength information of the positioning database 11 to be updated is the same grid as the update strength information (that is, the update target data is determined by the grid). It may not be judged by. For example, the intensity information in the positioning database 11 corresponding to the position closest to the position indicated by the position information corresponding to the update intensity information and corresponding to a position within a certain threshold may be used as the update target. .

  In the above description, the strength information used for calculating the representative DL is not used as the update strength information (that is, the information before the detection of the network change is not used), but the strength information is used. It is good as well. For example, the intensity information used for calculating the representative DL may be used as the intensity information for updating from the later (new) time indicated by the time information.

  In addition to the update of the intensity information, the accuracy information stored in the positioning database 11 may be updated by the same method as the update method of the intensity information. Further, the time stamp and update count of the updated pattern data may be updated. The time stamp stores information on the time of update. The number of updates is incremented by one. However, as will be described later, the normal update and the update at the time of network change are separated, and the update at the time of the network change as in this embodiment may be reset (set to 0). . The above is the functional configuration of the positioning server 10 according to the present embodiment.

  FIG. 6 shows a hardware configuration of the positioning server 10. As shown in FIG. 6, the positioning server 10 includes a CPU 101, a RAM (Random Access Memory) 102 and a ROM (Read Only Memory) 103, which are main storage devices, a communication module 104 for performing communication, and an auxiliary storage device such as a hard disk. The computer is configured to include a computer having hardware such as 105. The functions of the positioning server 10 described above are exhibited when these components are operated by a program or the like.

  Subsequently, processing (database management method) executed by the positioning server 10 according to the present embodiment will be described using the flowcharts of FIGS. 7 and 8.

  First, in the positioning server 10, a positioning request for GPS positioning is made from the position information receiving unit 13 to the cellular terminal 20 (S01). The positioning request is periodically made as described above. In the cellular terminal 20, the positioning request is received, GPS positioning is performed using the positioning request as a trigger, and intensity information (a radio wave intensity pattern) indicating the reception intensity of the radio wave corresponding to the cellular base station 30 at that position is received. Measured. Subsequently, the strength information and the position information of the cellular terminal 20 obtained by GPS positioning are transmitted from the cellular terminal 20 to the positioning server 10 in association with each other. This intensity information is associated with time information. The transmission of the GPS positioning request in S01 is repeatedly performed at a constant time interval T2, and as a result, the subsequent processing is repeatedly performed.

  Subsequently, in the positioning server 10, the strength information receiving unit 12 receives the strength information (the pattern of the radio wave strength) and the time information indicating the radio wave reception strength according to the cellular base station 30 transmitted from the cellular terminal 20. (S02, intensity information receiving step). Further, the position information receiving unit 13 receives the position information transmitted from the cellular terminal 20 (S02, position information receiving step). The intensity information, time information, and position information are input to the environment change detection unit 14 and the update unit 16. Here, update processing (S09, S10) by the update unit 16 is performed, which will be described later.

  On the other hand, subsequently, the environment change detection unit 14 specifies a grid of the electric field map 60 based on the position information, and stores intensity information and time information in association with the grid (S03, environment change detection step). . Subsequently, the environment change detection unit 14 calculates the average received intensity for each grid and the cellular base station 30 using the intensity information received and stored during the time T from the time (S04, environment). Change detection step). The calculated average value is stored by the environment change detection unit 14. Note that the above calculation process is not necessarily performed every time after S03, but is performed at a predetermined timing after a positioning request is made from the position information receiving unit 13 (S01).

Subsequently, the environment change detecting unit 14, a difference DL _g in each grid g of average received intensity _{L tn} in the stored latest time point _{t n} and the average receiving intensity _{L tn-1} at the previous time _{t n-1} Is calculated (S05, environment change detection step). Subsequently, a representative DL, which is an index value for detecting a network change, is calculated from the calculated difference DL _g (S06, environment change detection step). Subsequently, the environment change detection unit 14 determines whether or not the representative DL is larger than the threshold value TL, and a network change is detected based on this determination (S07, environment change detection step).

  Information relating to the determination of the network change is input from the environment change detection unit 14 to the update unit 16. Subsequently, when the update unit 16 determines that there is a network change based on the information, the following update processing of the positioning database 11 is performed. First, the update unit 16 specifies (sets) the grid related to the average reception level used for calculating the representative DL as a grid to be updated (S08, update step). Here, a series of processes related to the detection of the network change from S02 ends.

  Subsequently, after the grid to be updated is specified by the above processing, the strength information and time information are newly received by the strength information receiving unit 12, and the position information is received by the position information receiving unit 13. Is input to the update unit 16 (S02, intensity information reception step, position information reception step), the following processing is performed.

  First, the updating unit 16 determines whether the position information input from the position information receiving unit 13 is included in the update target grid (S09, update step). If it is determined that the position information is not included in the grid, the positioning database 11 is not updated. When it is determined that the position information is included in the grid, the updating unit 16 performs an update process of the positioning database 11 (S10, update step).

This update process will be described more specifically with reference to the flowchart of FIG. First, the updating unit 16, the updated weight _{W g} for (pre-update) intensity information is determined from the representative DL and the difference DL _g as described above (S11, update step). Here, the representative DL and the difference DL _g are input from the environment change detection unit 14 as information related to the network change. Subsequently, the update unit 16 calculates the updated intensity information DB _new from the intensity information DB _old before update, the intensity information Data _MR for update, and the determined weight W _g by using the above-described formula. (S12, update step). Subsequently, the update unit 16 stores the calculated intensity information DB _{new in} the positioning database 11 instead of the intensity information DB _old before update (S13, update step). The above is the positioning process executed by the positioning server 10 according to the present embodiment.

  In addition, when the cellular terminal 20 performs GPS positioning spontaneously, the above process is not performed, the process of S01 is not performed, and the process is started from S02. In that case, the calculation of the average value of the reception intensity at the constant time T in S04 is performed at every constant time interval T2. In this case, the information of the reception intensity for each grid in S03 may be stored only for the above-mentioned fixed time T because the information may increase.

  As described above, according to the positioning server 10 according to the present embodiment, since the positioning database 11 is updated based on the network change, the positioning database 11 can be appropriately updated. That is, when it is determined that there is a network change, it is possible to perform the update by lowering (resetting) the influence degree of the information before the update, and the more appropriate the information stored in the positioning database 11 Can be in a state.

  Further, if the calculation is performed for each grid by dividing into grids as in the present embodiment, positions that are close to each other can be easily determined, and thus the present invention is easily implemented in that respect. Can do. However, it is not always necessary to divide into grids, and the vicinity may be determined based on the distance between the positions.

  In addition, if the reception intensity is averaged in two time zones T having a predetermined time interval as in the present embodiment, the above temporal change can be appropriately detected according to the time interval. Can do. As a result, the database can be updated reliably and more appropriately.

Also, as in the present embodiment, if the positioning database 11 is taken into consideration data before updating using the weight W _g when updating updates the appropriate database in accordance with the degree of the network changes update It becomes possible to do. However, when a network change is detected, a uniform update may be performed in which no data before updating the grid is taken into consideration.

  In the above-described embodiment, the positioning database 11 is updated only when the network change is detected. However, the positioning database 11 is also updated when the network change is not detected. It is good also as performing. That is, not only when the data is determined to be within the update range in S10 (update when the network is changed), but also when the data is determined not to be within the update range, the positioning database 11 is updated (normally Update). The update (normal update) in this case is an update for increasing the accuracy of the positioning database 11. In the normal update, the influence level of the new reception strength (reception strength related to the strength information input from the strength information receiving unit 12) is made smaller than that at the time of the network change, for example, the new reception strength is updated. The update is performed using one of the reception strengths for obtaining an average value to be a later reception strength.

The threshold value TL can be a value corresponding to the time interval between the times t _n and t _{n−1 at} which the difference is taken. For example, if the time interval is small, a small network change can be detected with a (relatively) small threshold, and if the time interval is large, a large network change is detected with a (relatively) large value. Can be able to.

  In the present embodiment, the position information is a positioning result by GPS positioning. However, the position information obtained by other positioning methods such as positioning using RTT (Round Trip Time) of radio waves transmitted and received by the cellular terminal 20 is used. It may be used.

  In the above-described embodiment, the information stored in the positioning database 11 and used for positioning uses the reception intensity of radio waves received by the cellular terminal 20 (downlink), but is transmitted from the cellular terminal 20. Thus, the reception intensity of radio waves received by the cellular base station 30 may be used (uplink). Even in this case, the configuration and usage of the positioning database 11 can be the same as those described above.

  Further, the positioning database 11 described above may be prepared for each model of the cellular terminal 20, and positioning or database update may be performed using a different positioning database 11 for each model. Even in this case, the configuration and usage of the positioning database 11 can be the same as those described above.

  In the above-described embodiment, the detection of the network change is performed as a pre-process for updating the positioning database 11, but it may be a device (system) having the characteristics of only that portion. That is, it can be configured as a reception environment change detection system without the positioning database 11 and the updating unit 16 of the positioning server 10 described above. In this case, information related to the network change detected by the environment change detection unit 14 is output to a display unit or the like provided in another device or the own device. For example, when information related to a network change is displayed, the user can know the network change by viewing it. Information relating to such a network change is used for the creation of an electric field map as described above by a communication carrier.

It is a figure which shows the function structure of the positioning server which is a database management system which concerns on embodiment of this invention. It is a table which shows the information hold | maintained at the database for positioning. It is a figure which shows notionally the electric field map hold | maintained in a positioning server. It is a figure which shows the range of time which calculates the average value of receiving intensity. It is a figure which shows the example of the information of the reception strength hold | maintained at the positioning database before and behind an update. It is a figure which shows the hardware constitutions of the positioning server which concerns on embodiment of this invention. It is a flowchart which shows the process (database management method) performed with the positioning server which concerns on embodiment of this invention. It is a flowchart which shows the process (database management method) performed with the positioning server which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Positioning server, 11 ... Positioning database, 12 ... Strength information receiving part, 13 ... Position information receiving part, 14 ... Environmental change detecting part, 16 ... Update part, 101 ... CPU, 102 ... RAM, 103 ... ROM, 104 ... Communication module 105 ... Auxiliary storage device 20, 21 ... Cellular terminal, 30 ... Cellular base station, 40 ... GPS satellite.

Claims (9)

A database management system for managing a database used for positioning of a mobile communication terminal and holding information indicating a relationship between a reception intensity and a position of the radio wave according to a radio wave transmission source,
Intensity information receiving means for receiving intensity information indicating reception intensity of radio waves according to the transmission source received or transmitted by the mobile communication terminal;
Position information receiving means for receiving position information indicating a position where the radio wave is received or transmitted by the mobile communication terminal related to the intensity information received by the intensity information receiving means;
Information on the first reception intensity of the radio wave received or transmitted at the first time, received by the intensity information receiving means, and second in the vicinity of the position corresponding to the information on the first reception intensity. Compared with the second received intensity information of the radio wave received or transmitted at the time of the time, there was a temporal change in the radio wave reception environment in the mobile communication terminal at the position based on the comparison result Environmental change detection means for detecting
An update for updating the database in accordance with the change detected by the environment change detecting means based on the intensity information received by the intensity information receiving means and the position information received by the position information receiving means. Means,
A database management system comprising:   2. The database management system according to claim 1, wherein the environment change detection unit divides an area where the change is detected into a grid, and sets a position in the same grid as the vicinity.   3. The database management system according to claim 1, wherein the first time and the second time are respectively included in a first time zone and a second time zone having a predetermined time interval. .   4. The database management system according to claim 1, wherein at least one of the first reception strength information and the second reception strength information is plural.   The environment change detection means, as the comparison, takes a difference between an average of received strength related to the information of the first received strength and an average of received strength related to the information of the second received strength. The database management system according to claim 4.   The update means updates the database so that the degree of influence of information before update becomes smaller as the change detected by the environment change detection means becomes larger. The database management system according to one item. A database management method for managing a database used for positioning of a mobile communication terminal and holding information indicating a relationship between a reception intensity and a position of the radio wave according to a radio wave transmission source,
An intensity information receiving step for receiving intensity information indicating reception intensity of radio waves according to the transmission source received or transmitted by the mobile communication terminal;
A position information receiving step of receiving position information indicating a position at which the radio wave is received or transmitted by the mobile communication terminal related to the intensity information received in the intensity information receiving step;
Information on the first reception intensity of the radio wave received or transmitted at the first time, received in the intensity information reception step, and second in the vicinity of the position corresponding to the information on the first reception intensity. Compared with the second received intensity information of the radio wave received or transmitted at the time of the time, there was a temporal change in the radio wave reception environment in the mobile communication terminal at the position based on the comparison result An environmental change detection step for detecting
Updating to update the database according to the change detected in the environmental change detection step based on the strength information received in the strength information reception step and the location information received in the location information reception step Steps,
Database management method including. Intensity information receiving means for receiving intensity information indicating reception intensity of radio waves according to a radio wave transmission source received or transmitted by a mobile communication terminal;
Position information receiving means for receiving position information indicating a position where the radio wave is received or transmitted by the mobile communication terminal related to the intensity information received by the intensity information receiving means;
Information on the first reception intensity of the radio wave received or transmitted at the first time, received by the intensity information receiving means, and second in the vicinity of the position corresponding to the information on the first reception intensity. Compared with the second received intensity information of the radio wave received or transmitted at the time of the time, there was a temporal change in the radio wave reception environment in the mobile communication terminal at the position based on the comparison result Environmental change detection means for detecting
Output means for outputting information indicating the change detected by the environment change detection means;
A reception environment change detection system comprising: An intensity information receiving step for receiving intensity information indicating the reception intensity of the radio wave corresponding to the radio wave source that is received or transmitted by the mobile communication terminal;
A position information receiving step of receiving position information indicating a position at which the radio wave is received or transmitted by the mobile communication terminal related to the intensity information received in the intensity information receiving step;
Information on the first reception intensity of the radio wave received or transmitted at the first time, received in the intensity information reception step, and second in the vicinity of the position corresponding to the information on the first reception intensity. Compared with the second received intensity information of the radio wave received or transmitted at the time of the time, there was a temporal change in the radio wave reception environment in the mobile communication terminal at the position based on the comparison result An environmental change detection step for detecting
An output step of outputting information indicating the change detected in the environmental change detection step;
Receiving environment change detecting method including:

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