JP2018146484A - Information processing apparatus, information processing program, and information processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an information processing device having scarce computational resources to specify the position of its own device. SOLUTION: One of a plurality of transmitters 21 is closer to its own device than another transmitter 21, and the attenuation amount att_P0 of the radio wave intensity of one transmitter 21 is another transmission. When the radio wave intensity of the device 21 is larger than the attenuation att_P3, the position of the own device is estimated using the correction unit 53 that reduces the attenuation att_P0 of one transmitter 21 and the attenuation att_P0 after the correction. According to an information processing device having a position estimation unit 55 and the like. [Selection diagram] FIG. 11

Description

  The present invention relates to an information processing apparatus, an information processing program, and an information processing method.

  With the widespread use of IoT (Internet of Things) devices, various services using information processing devices such as IoT devices have been proposed. One such service is a watch service for elderly people wearing IoT devices. In addition, there is a service that acquires a user action log including information “I went here at this time”.

  These services can be realized by the information processing apparatus positioning its own position by some method.

  However, it is difficult for an information processing device such as an IoT device that is small and lacks computing resources to accurately identify the location of its own device.

JP, 2006-045127, A JP 2006-300918 A JP 2009-198454 A

  An object of one aspect of the present invention is to enable an information processing apparatus with scarce computing resources to specify the position of its own apparatus.

  In one aspect, the transmitter of one of a plurality of transmitters is closer to its own device than the other transmitters, and the attenuation of the radio field intensity of the one transmitter is the other transmission. A correction unit for performing correction to reduce the attenuation of the one transmitter when the attenuation of the radio field intensity of the transmitter is larger, and position estimation for estimating the position of the own device using the corrected attenuation An information processing apparatus having a unit is provided.

  In one aspect, according to the present invention, even an information processing apparatus with scarce computing resources can identify the position of its own apparatus.

FIG. 1 is a schematic diagram of the system used for the study. FIG. 2 is a graph showing an example of multipath fading. FIG. 3 is a schematic diagram (part 1) for explaining the principle of the first embodiment. FIG. 4 is a schematic diagram (part 2) for explaining the principle of the first embodiment. FIG. 5 is a schematic diagram for explaining the principle of preventing inconvenience due to multipath fading in the first embodiment. FIG. 6 is a schematic diagram illustrating the overall configuration of the first embodiment. FIG. 7 is a plan view (part 1) illustrating the positional relationship between the information processing apparatus and each transmitter in the first embodiment. FIG. 8 is a plan view (part 2) illustrating the positional relationship between the information processing apparatus and each transmitter in the first embodiment. FIG. 9 is a schematic diagram (part 1) for explaining the correction method according to the first embodiment. FIG. 10 is a schematic diagram (part 2) for explaining the correction method according to the first embodiment. FIG. 11 is a schematic diagram (No. 3) for explaining the correction method according to the first embodiment. FIG. 12 is a hardware configuration diagram of the information processing apparatus according to the first embodiment. FIG. 13 is a functional configuration diagram of the information processing apparatus according to the first embodiment. FIG. 14 is a schematic diagram of a link node map used by the beacon candidate clip unit according to the first embodiment. FIG. 15 is a schematic diagram illustrating an example of a method of excluding a transmitter by a beacon candidate clip unit in the first embodiment. FIG. 16 is a schematic diagram illustrating another example of how a transmitter is excluded by a beacon candidate clip unit in the first embodiment. FIG. 17 is a schematic diagram for explaining the function of the inclusion determination unit according to the first embodiment. FIG. 18 is a schematic diagram of an attenuation amount table according to the first embodiment. FIG. 19 is a schematic diagram of a correlation table according to the first embodiment. FIG. 20 is a diagram schematically illustrating a position estimation method using the correlation table according to the first embodiment. FIG. 21 is a graph for schematically explaining processing performed by the time-series correction processing unit according to the first embodiment. FIG. 22 is a flowchart (part 1) illustrating a process performed by the time-series correction processing unit according to the first embodiment. FIG. 23 is a flowchart (part 2) illustrating the process performed by the time-series correction processing unit according to the first embodiment. FIG. 24 is a schematic diagram (No. 1) for describing a method of estimating a future change in radio wave intensity in the first embodiment. FIG. 25 is a schematic diagram (part 2) for describing a method of estimating a future change in radio wave intensity in the first embodiment. FIG. 26 is a schematic diagram for explaining a calculation method of the first estimated value and the second estimated value of the radio field intensity in the first embodiment. FIG. 27 is a schematic diagram of a correction graph obtained by graphing the correction value of the radio wave intensity in the first embodiment. FIG. 28 is a flowchart for explaining the information processing method according to the first embodiment. FIG. 29 is a schematic diagram (part 1) for explaining a correction method according to the second embodiment. FIG. 30 is a schematic diagram (part 2) for explaining a correction method according to the second embodiment. FIG. 31 is a schematic diagram (No. 3) for explaining the correction method according to the second embodiment. FIG. 32 is a schematic diagram (part 1) for explaining a correction method according to the second embodiment. FIG. 33 is a schematic diagram for explaining a correction method according to another example of the second embodiment. FIG. 34 is a functional configuration diagram of the information processing apparatus according to the third embodiment. FIG. 35 is a schematic diagram of a link node map used in the third embodiment. FIG. 36 is a schematic diagram for explaining a correction method according to the third embodiment. FIG. 37 is a schematic diagram when the attenuation amount of the radio field intensity is larger than the estimated value in the third embodiment. FIG. 38 is a schematic diagram when the attenuation of radio field intensity is corrected in the third embodiment.

  Prior to the description of the present embodiment, items studied by the inventor will be described.

  There is a method using GPS (Global Positioning System) as a method for an information processing apparatus such as an IoT device to identify the position of its own device, but it is difficult to use GPS indoors where signals from GPS satellites are difficult to reach.

  In order for an information processing apparatus to perform positioning indoors, a radio wave transmitter is fixed at a predetermined position indoors, and based on the radio wave emitted by the transmitter and the position of the transmitter, the information processing apparatus What is necessary is just to specify the position of. An example of such a transmitter is a beacon using Bluetooth (registered trademark), for example. Since an advertisement signal is transmitted from the beacon at regular intervals, it is possible to perform positioning using the radio wave intensity of the received advertisement signal by knowing information on the beacon installation position in advance.

  In that case, the information processing device can determine the direction in which the radio waves from the beacon arrive, but for the IoT devices that are prevalent in the market, there is a highly functional antenna that can identify the direction of the radio waves. Not provided.

  Although methods have been proposed for positioning based only on the radio wave intensity of the beacon observed by the device owned by the user, it is difficult to implement the method using a device with limited computational resources such as an IoT device.

  For example, a method has been proposed in which an information processing apparatus acquires the radio field intensity of a radio wave emitted from a wireless LAN (Local Area Network) access point and specifies the position of the information processing apparatus based on the radio field intensity. This method uses a particle filter that requires a large amount of computational resources and power consumption, and it is difficult to realize this method with a device that lacks computational resources, such as an IoT device.

  Similarly, there is a method in which a plurality of wireless nodes receive radio waves emitted from a wireless terminal and specify the position of the wireless terminal based on the received radio field intensity. In this method, the location of the wireless terminal is specified by performing repeated calculations so that the evaluation function, which is a function of the theoretical value and the actual measurement value of the radio field intensity, is minimized, and a large amount of computational resources and power consumption are reduced. It is difficult for an IoT device to perform the necessary repetitive calculations.

  Therefore, the inventor of the present application examined another method of positioning using only the radio wave intensity of a beacon observed by an information processing apparatus such as an IoT device.

  FIG. 1 is a schematic diagram of the system used for the study.

  This system 1 is a system in which an information processing apparatus 3 existing indoors measures its own position, and a plurality of transmitters 4 are fixed at predetermined indoor positions.

  Among these, the information processing apparatus 3 is a device that is small and has limited computational resources, such as an IoT device. Each transmitter 4 is a beacon that periodically transmits an advertisement signal.

In this example, the position of each transmitter 4 is represented by points P _{1 to} P ₃ . The information processing device 3 is assumed to know the positions P _{1 to} P ₃ of the transmitters 4. Further, it is assumed that the information processing apparatus 3 also knows the radio field intensity of the advertised signal observed immediately near each transmitter 4. These radio field intensities are written as ori_P ₁ , ori_P ₂ , and ori_P ₃ below.

Furthermore, the information processing device 3 calculates these actual radio wave intensities obs_P ₁ , obs_P ₂ , and obs_P ₃ measured by itself.

Since each transmitter 4 is located away from the information processing device 3, the radio wave intensity of the advertised signal emitted by each transmitter 4 is attenuated before reaching the information processing device 3. Hereinafter, the attenuation of the radio field intensity of the advertised signal emitted by the transmitter 4 at each point P _{1 to} P ₃ is written as att_P _{1 to} att_P ₃ , respectively. From this definition, the following equation (1) holds.

Here, the attenuation amounts att_P _{1 to} att_P ₃ increase as the distance between the information processing device 3 and each transmitter 4 increases. Conversely, if the distance between the information processing device 3 and the transmitter 4 is shortened, the attenuation amounts att_P _{1 to} att_P ₃ decrease.

If this is utilized, the position of the information processing apparatus 1 can be estimated based on the respective attenuation amounts att_P _{1 to} att_P ₃ . In addition, since only the attenuation amounts att_P _{1 to} att_P ₃ are used for estimation, even a weak information processing apparatus 3 such as an IoT device can estimate the position of the own apparatus.

  However, in a space where there is an obstacle that reflects radio waves, such as indoors, the radio wave intensity of the advertised signal that is observed may attenuate more than attenuation due to the distance between the information processing device 3 and the transmitter 4. Such a phenomenon is called multipath fading.

  Multipath fading occurs because the phase of the signal that reaches the information processing apparatus 4 after being reflected by an indoor obstacle is different from the signal that reaches the information processing apparatus 4 directly from the transmitter 3.

  FIG. 2 is a graph showing an example of multipath fading.

  The horizontal axis of this graph represents time, and the vertical axis represents the radio field intensity of the advertised signal output from a certain beacon.

  In the example of FIG. 2, the radio wave is attenuated in the period T due to multipath fading. The decaying period ranges from several seconds to 20 seconds.

When the attenuation amounts att_P ₁ , att_P ₂ , and att_P ₃ increase numerically due to multipath fading, the position of the information processing apparatus 1 estimated by these attenuation amounts becomes inaccurate.

  The inventor of the present application has studied several methods for reducing the influence of such multipath fading, but all have the following problems.

  For example, a method of providing the information processing apparatus 3 with a high-quality antenna dedicated to positioning that can reduce the influence of multipath fading has been studied. However, this method cannot be applied to a device having only a communication antenna such as a small information processing apparatus 3 such as an IoT device.

  We also considered a method of discarding the radio wave when the radio wave intensity was below the specified value, and performing positioning by relying only on radio waves with a strength greater than the specified value. However, this method is not practical because the user who has the information processing device 3 needs to be close to each transmitter 4 so that the radio field intensity is greater than the specified value.

  Furthermore, a method of holding the peak value of the radio field intensity with a peak hold circuit and performing positioning using the peak value was also examined. However, since the period during which radio waves are attenuated by multipath fading is long as described above, when the user moves, it is not possible to perform positioning with sufficient accuracy.

  In addition, the method of transmitting the radio wave intensity received by the information processing device 3 to a computer having abundant calculation resources such as a server without forcibly positioning the information processing device 3 and performing the positioning by the computer was also examined. In this method, a radio wave intensity map indicating a measure of the radio wave intensity distribution is created, and a position corresponding to the actual radio wave intensity received by the information processing device 3 is obtained from the radio wave intensity map. However, this method requires a great deal of labor to create a radio wave intensity map.

  Hereinafter, each embodiment capable of performing positioning only with the radio wave intensity while suppressing the influence due to multipath fading will be described.

(First embodiment)
First, the principle of this embodiment will be described.

  3 to 4 are schematic views for explaining the principle of the present embodiment.

  In the example of FIG. 3, it is assumed that the information processing apparatus 20 and the two transmitters 21 are indoors.

Each transmitter 21 is a beacon that emits an advertisement signal, for example, and is fixed to point P ₀ and point P ₁ , respectively.

It is assumed that the radio wave intensities ori_P ₀ and ori_P ₁ of the advertisement signals immediately after being output from each transmitter 21 are the same, and the information processing apparatus 20 stores these values. Also, RSSI (Received Signal Strength Indicator) is used below as an indicator of the radio field strengths ori_P ₀ and ori_P ₁ .

  Furthermore, instead of a Bluetooth (registered trademark) device, a wireless LAN access point may be provided as each transmitter 21.

On the other hand, the information processing apparatus 20 is an IoT device, for example. The information processing device 20 measures the actual received radio wave strengths obs_P ₀ and obs_P ₁ of the advertised signal output from each transmitter 21 around the own device, and estimates the position of the own device using these radio wave strengths. .

In estimating the position, the fact that the radio signal strengths obs_P ₀ and obs_P _{1 of the} advertised signal are attenuated as the information processing device 20 is separated from each transmitter 21 is used.

Hereinafter, the attenuation of the radio field intensity of each advertisement signal is written as att_P ₀ and att_P ₁ . From the definition, att_P ₀ = ori_P ₀ -obs_P ₀ , and att_P ₁ = ori_P ₁ -obs_P ₁ . These attenuation att_P _0, att_P ₁ is radio wave strength Obs_P _0, calculates the measured value of obs_P _{1, ori_P 0} which is the radio field intensity of the most recent of each transmitter 21, the information processing apparatus 20 based on the Ori_P ₁ is To do.

The method of estimating the position is not particularly limited. For example, when the attenuation amount att_P ₀ is smaller than the attenuation amount att_P ₁ , it can be estimated that the information processing apparatus 20 is located closer to the point P ₀ than the point P ₁ .

On the other hand, FIG. 4 is a schematic diagram when the radio field intensity of the advertised signal emitted from the transmitter 21 at the point P ₀ is affected by multipath fading.

In this case, the attenuation amount att_P ₀ is larger than the attenuation amount att_P _{1 due} to multipath fading.

Therefore, in this case, if the information processing apparatus 20 performs positioning based on the attenuation amounts att_P ₀ and att_P ₁ , it is erroneously estimated that the own apparatus is positioned closer to the point P ₁ than the point P ₀ .

  FIG. 5 is a schematic diagram for explaining the principle for preventing such inconvenience.

In this example, when the attenuation amount att_P ₀ is larger than the attenuation amount att_P ₁ as described above due to multipath fading, the information processing apparatus 20 performs correction to reduce the attenuation amount att_P ₀ . The correction amount of the attenuation amount att_P ₀ is not particularly limited. For example, the attenuation amount att_P ₀ is corrected so as to be equal to the attenuation amount att_P ₁ of the remote transmitter 21.

By correcting the attenuation amount att_P ₀ in this manner, the position error of the information processing apparatus 20 estimated from the attenuation amounts att_P ₀ and att_P ₁ can be reduced.

  Next, a specific example of this embodiment will be described.

<Overall configuration>
FIG. 6 is a schematic diagram showing the overall configuration of the present embodiment.

  In FIG. 6, the same elements as those described in FIG. 5 are denoted by the same reference numerals as those in FIG. 5, and description thereof will be omitted below.

  As shown in FIG. 6, in the present embodiment, a plurality of transmitters 21 are fixed at predetermined positions on the ceiling 28, and a user U carrying the information processing apparatus 20 is moving in an indoor 23. Is assumed.

  In addition, the site | part which fixes the transmitter 21 is not limited to the ceiling 28. FIG. The transmitter 21 may be fixed to a wall or floor.

  Then, based on the radio field intensity of the advertised signal emitted from each transmitter 21, the information processing apparatus 20 estimates the position of the own apparatus as will be described later.

  7 and 8 are plan views showing the positional relationship between the information processing apparatus 20 and each transmitter 21. FIG.

In the example of FIGS. 7 and 8 indicates the position of the information processing apparatus 20 at point A, which represents the position of each transmitter 21 at each point P ₀ to P _3.

In FIG. 7, it is assumed that a triangle P ₁ P ₂ P ₃ having vertices at points P _{1 to} P ₃ includes both point P ₀ and point A.

On the other hand, in FIG. 8, it is assumed that the triangle P ₁ P ₂ P ₃ contains the point P ₀ and the point A is located outside the triangle P ₁ P ₂ P ₃ .

Hereinafter, the distance between the point A and the points P _{0 to} P ₃ will be written as d _A0 , d _A1 , d _A2 , and d _A3 , respectively.

7 and 8, the distance d _A0 between the point A and the point P ₀ is always smaller than the largest geometrically remaining distances d _A1 , d _A2 , d _A3. Become.

That is, if the transmitter 21 represented by the point P ₀ is included in the triangle P ₁ P ₂ P ₃ , the points P _{1 to} P are located wherever the information processing device 20 represented by the point A is located. That is, at least one of the transmitters 21 represented by ₃ is located farther than P _{0 when} viewed from the information processing apparatus 20.

  In the present embodiment, the attenuation of the radio field intensity of the advertised signal output from each transmitter 21 is corrected as follows using such geometrical knowledge.

  9 to 11 are schematic diagrams for explaining the correction method.

Among these, FIG. 9 illustrates a case where the radio wave intensity of the advertised signal output from the transmitter 21 at the point P ₀ is increased more than originally due to multipath fading.

Hereinafter, the field intensity of the advertisement signal to be measured in the most recent each transmitter 21 each represent at ori_P ₀ ~ori_P _3, the actual field intensity of advertising signal processing apparatus 20 is measured at each obs_P ₀ ~obs_P ₃ It shall represent.

In this example, the radio field intensities ori_P _{0 to} ori_P ₃ observed in the immediate vicinity of each beacon are all the same, but in reality, the installation environment and the output radio field intensity may be different for each transmitter 21, thereby Intensities ori_P _{0 to} ori_P ₃ may not be the same.

Also, the radio wave intensity of these advertisement signals is attenuated before reaching the information processing apparatus 20. The attenuation amounts are represented by att_P _{0 to} att_P ₃ , respectively.

At this time, as described above, wherever the information processing apparatus 20 is located, at least one of the points P _{1 to} P ₃ is located farther from the point P _{0 when} viewed from the information processing apparatus 20.

Therefore, if there is no impact due to multipath fading, since at least one of att_P ₁ ~att_P ₃ is greater than Att_P _0, the maximum value Max of _{att_P 1 ~att_P 3 (att_P 1,} att_P 2, att_P 3) Than att_P ₀ should be smaller.

Conversely, when att_P ₀ is larger than the maximum value Max (att_P ₁ , att_P ₂ , att_P ₃ ) as in the example of this figure, the advertised signal from the transmitter 21 at point P ₀ is caused by multipath fading. It can be judged that it has attenuated abnormally.

Therefore, when it is determined in this way, att_P ₀ is corrected as shown in FIGS.

FIG. 10 illustrates a case where Max (att_P ₁ , att_P ₂ , att_P ₃ ) = att_P ₃ and att_P ₀ > Max (att_P ₁ , att_P ₂ , att_P ₃ ). In this case, since att_P ₃ is the largest among att_P _{1 to} att_P ₃ , the point P ₃ is farthest from the information processing device 20, and the point P ₀ is closer to the information processing device 20 than the point P _3. It will be.

Therefore, in this case, att_P ₀ is subtracted by correction to make the value equal to the attenuation amount att_P ₃ at the farthest point P ₃ .

  FIG. 11 is a schematic diagram after such correction.

By correcting att_P ₀ so that att_P ₃ = att_P _{0 in} this way, the value of att_P ₀ matches the situation where the point P ₀ is included in the triangle P ₁ P ₂ P ₃ . Therefore, the information processing apparatus 20 estimates the position of the own apparatus using the corrected attenuation amount att_P ₀ and the attenuation amounts att_P _{1 to} att_P ₃ , thereby improving the estimation accuracy.

When att_P ₀ ≤ Max (att_P ₁ , att_P ₂ , att_P ₃ ), the value of att_P ₀ matches the situation where the point P ₀ is included in the triangle P ₁ P ₂ P _3. Therefore, att_P ₀ is not corrected.

  Next, the information processing apparatus 20 that realizes such a correction method will be described.

<Hardware configuration>
FIG. 12 is a hardware configuration diagram of the information processing apparatus 20 according to the present embodiment.

  As illustrated in FIG. 12, the information processing apparatus 20 includes an antenna 31, a wireless unit 32, an acceleration sensor 33, a gyro sensor 34, a geomagnetic sensor 35, a storage unit 36, a processor 37, and a memory 38.

  Among these, the antenna 31 receives an advertisement signal from each of the plurality of transmitters 21, and transmits and receives radio waves for data communication with a base station of a mobile phone or an access point of a wireless LAN.

  The wireless unit 32 converts the advertisement signal received by the antenna 31 into an electrical signal and outputs the electrical signal to the processor 37. Further, the wireless unit 32 modulates and demodulates various signals transmitted and received between the antenna 31 and the processor 37.

  Further, the acceleration sensor 33 detects the acceleration applied to the device itself, and outputs a signal indicating the acceleration value to the processor 37.

  The gyro sensor 34 detects a change in posture of the device itself and outputs a signal indicating how much the posture is changed to the processor 37.

  Then, the geomagnetic sensor 35 outputs a signal indicating which direction the device is facing to the processor 37 by detecting the geomagnetism.

  The storage unit 36 is, for example, a nonvolatile storage such as a ROM (Read Only Memory), a nonvolatile RAM (Random Access Memory), a flash memory, an EEPROM (Electrically Erasable Programmable ROM), and a hard disk.

  The storage unit 36 stores an information processing program 41 according to the present embodiment.

  The information processing program 41 may be recorded on a computer-readable recording medium 45 and the processor 37 may read the information processing program 41 on the recording medium 45.

  Examples of such a recording medium 45 include a physical portable recording medium such as a CD-ROM (Compact Disc-Read Only Memory), a DVD (Digital Versatile Disc), and a USB (Universal Serial Bus) memory. Further, a semiconductor memory such as a flash memory or a hard disk drive may be used as the recording medium 45. These recording media 45 are not temporary media such as carrier waves having no physical form.

  Further, the information processing program 41 may be stored in a device connected to a public line, the Internet, a LAN, or the like, and the processor 37 may read and execute the information processing program 41.

  The processor 37 is hardware such as a CPU (Central Processing Unit) that controls each unit of the device itself and executes the information processing program 41 in cooperation with the memory 38.

  Furthermore, the processor 37 grasps the trajectory of the action of the user carrying the information processing apparatus 20 based on the outputs of the acceleration sensor 33, the gyro sensor 34, and the geomagnetic sensor 35.

  The memory 38 is hardware that temporarily stores data, such as DRAM (Dynamic RAM), on which the information processing program 41 is developed.

Note that the values of the radio field strengths ori_P _{0 to} ori_P ₃ of the advertised signal immediately after leaving the transmitter 21 at the points P _{0 to} P ₃ are also stored in the memory 38 in advance.

<Functional configuration>
FIG. 13 is a functional configuration diagram of the information processing apparatus 20.

  As illustrated in FIG. 13, the information processing apparatus 20 includes a radio wave intensity input unit 51, a time series correction processing unit 52, a correction unit 53, a radio wave intensity storage unit 54, and a position estimation unit 55. These units are realized by the processor 37 executing the information processing program 41 in cooperation with the memory 38.

Among these, the radio wave intensity input unit 51 measures the radio wave intensity of the advertise signal input from the radio unit 32 (see FIG. 12). The measurement values obs_P _{0 to} obs_P ₃ are notified to the time series correction processing unit 52 by the radio wave intensity input unit 51 and stored in the memory 38.

The time-series correction processing unit 52 corrects the value of the notified radio wave intensities obs_P _{0 to} obs_P ₃ due to multipath fading, and notifies the correction unit 53 of the corrected radio wave intensity. Details of the correction method will be described later. Further, when it is not necessary to correct the radio field intensity, the time series correction processing unit 52 may be omitted.

On the other hand, the correction unit 53 obtains the attenuation att_P ₀ ~att_P ₃ by reducing the radio wave intensity obs_P ₀ ~obs_P ₃ from the radio wave intensity ori_P ₀ ~ori_P ₃ stored in the memory 38. When these attenuation amounts att_P _{0 to} att_P ₃ are larger than the original values due to multipath fading, the attenuation amounts att_P _{0 to} att_P ₃ are corrected to reduce the values. In the correction, geometric information such as the positional relationship between the own apparatus and each transmitter 21 is used as described later.

  In order to execute such correction, the correction unit 53 includes a beacon candidate clip unit 56, an inclusion determination unit 57, and an attenuation amount correction processing unit 58.

  14-16 is a schematic diagram for demonstrating the function of the beacon candidate clip part 56. FIG.

  FIG. 14 is a schematic diagram of a link node map 60 used by the beacon candidate clip unit 56.

The link node map 60 is a map in which each of the own device and the plurality of transmitters 21 is a node, and each of these nodes is connected by a link with a cost. In this example, each of the plurality of transmitters 21 is represented by points P _{0 to} P ₆ , and the current position of the information processing apparatus 20 is represented by a point A.

Also represent the points A, the cost of connecting the P ₀ to P ₆ in C ₀ -C _15. The costs C _{0 to} C ₁₅ are physical distances between points at both ends, for example.

The method for creating the link node map 60 is not particularly limited. For example, a Delaunay diagram can be created by a Delaunay algorithm using the positions of the points P _{0 to} P ₆ and A as input values, and the Delaunay diagram obtained thereby can be adopted as the link node map 60. In this case, the position of the point A that is the current position of the information processing apparatus 20 may be roughly grasped in advance based on an appropriate algorithm using the radio wave intensity of the advertised signal emitted from each transmitter 21.

  Note that it is preferable that a server having a higher computing ability than the information processing apparatus 20 creates the link node map 60.

  The beacon candidate clip unit 56 excludes the transmitter 21 located far away from the own device in the link node map 60. Thereby, the amount of attenuation of the radio field intensity of the excluded transmitter 21 is not used for correction in the attenuation amount correction processing unit 58, so that the calculation load of the information processing apparatus 20 can be reduced.

  FIG. 15 is a schematic diagram showing an example of a method of exclusion.

In this example, transmitters 21 at points P ₄ and P ₅ that are not directly connected to the current position indicated by point A via a link are excluded.

  FIG. 16 is a schematic diagram illustrating another example of the exclusion method.

In this example, transmitters 21 at points P _{4 to} P ₆ where the sum of costs starting from point A is equal to or greater than a predetermined value C _th are excluded.

Note that the beacon candidate clip unit 56 may exclude the transmitter 21 without using the link node map 60. For example, the beacon candidate clip unit 56 identifies the transmitter 21 having the strongest radio wave intensity obs_P _{0 to} obs_P ₆ among the transmitters 21 at the points P _{0 to} P _6, and is far from the identified transmitter 21 by a certain distance. The beacon candidate clip unit 56 may exclude the transmitter 21 at the position.

  Further, the beacon candidate clip unit 56 may exclude the transmitter 21 that is far from the own device and is not useful for positioning based on the past position of the own device or the floor on which the own device is located.

  Next, the function of the inclusion determination unit 57 will be described.

  FIG. 17 is a schematic diagram for explaining the function of the inclusion determination unit 57.

In FIG. 17, each transmitter 21 is represented by points P _{0 to} P ₃ as in FIGS. 9 to 11.

The inclusion determination unit 57 determines whether or not the triangle P ₁ P ₂ P ₃ includes the point P ₀ . The triangle P ₁ P ₂ P ₃ to be determined is a triangle formed by three points arbitrarily selected by the inclusion determination unit 57 from a plurality of points P _{0 to} P ₃ , and is shown in FIGS. It is not generated by the Delaunay algorithm.

This determination method is not particularly limited. In the present embodiment, as shown in FIG. 17, six vectors V ₁ , V ₂ , V ₃ , V ₄ , V ₅ and V ₆ are considered. When all the directions of the three outer products V ₁ × V ₂ , V ₃ × V ₄ , and V ₅ × V ₆ match, the inclusion determination unit 57 determines that the triangle P ₁ P ₂ P ₃ has the point P ₀ It is determined to be included.

  Refer to FIG. 13 again.

When the inclusion determination unit 57 determines that the triangle P ₁ P ₂ P ₃ includes the point P ₀ , the attenuation amount correction processing unit 58 performs the attenuation amount att_P according to the correction method described with reference to FIGS. Correct ₀ .

As described above, att_P ₀ is corrected when att_P ₀ > Max (att_P ₁ , att_P ₂ , att_P ₃ ), and att_P ₀ is corrected when att_P ₀ ≦ Max (att_P ₁ , att_P ₂ , att_P ₃ ) do not do.

In addition, the radio wave intensity accumulating unit 54 accumulates the values of the attenuation amounts att_P _{0 to} att_P ₃ acquired at each time in the memory 37 as an attenuation amount table. If there is any one of the attenuation amounts att_P _{0 to} att_P ₃ that has been corrected by an attenuation amount correction processing unit 58 described later, the radio wave intensity accumulation unit 54 creates an attenuation amount table based on the corrected attenuation amount. create.

  FIG. 18 is a schematic diagram of an attenuation amount table 59 at a certain time created by the radio wave intensity accumulating unit 54.

In the example of FIG. 18, subscripts 0 to ₃ of points P _{0 to} P ₃ are adopted as IDs for uniquely identifying each transmitter 21, and the position coordinates and attenuation amounts att_P ₀ to points P _{0 to} P ₃ are used. The value of att_P ₃ is associated with and stored in the attenuation amount table 59.

  Refer to FIG. 13 again.

The position estimation unit 55 estimates the position of the own apparatus at the time using the values of the attenuation amounts att_P _{0 to} att_P _{3 at} the same time.

  FIG. 19 is a schematic diagram of a correlation table 60 used for the estimation.

  The correlation table 60 is a table that represents the correlation between the weight used when estimating the position and the attenuation amount of the radio wave intensity, and is stored in the memory 37. Note that the value of the weight in the correlation table 60 is determined in advance by experiments or the like.

  FIG. 20 is a diagram schematically illustrating a position estimation method using the correlation table 60.

In the example of FIG. 20, it is assumed that the transmitter 21 is installed at the position represented by the points P _{0 to} P ₂ and the information processing apparatus 20 is located at the point A. Further, the memory 38 (see FIG. 12) of the information processing apparatus 20 stores the position coordinates (X ₀ , Y ₀ ), (X ₁ , Y ₁ ) of these points P _{0 to} P ₀ in the horizontal plane, Assume that (X ₂ , Y ₂ ) is stored in advance.

Then, when the attenuation amount of the transmitter 21 at each point P _{0 to} P ₂ measured by the own device is att_P _{0 to} att_P ₂ , the position estimating unit 55 determines the position coordinates of the own device according to the following equation (2). Calculate (X, Y).

However, W _{0 to} W ₂ are weights corresponding to the attenuation amounts att_P _{0 to} att_P ₂ , respectively, and are obtained with reference to the correlation table 60 described above.

Further, since each attenuation amount att_P _{0 to} att_P ₂ has an error, the position coordinates (X, Y) obtained according to the equation (2) also include a certain amount of error. Therefore, an estimation circle 61 that anticipates the error may be set, and the position estimation unit 55 that has a high possibility that the device is located in the estimation circle 61 may be estimated.

  Instead of obtaining the weight from the correlation table 60 as described above, the weight may be calculated based on a model in which the radio wave intensity is attenuated by the square of the distance.

  Furthermore, the weight may be obtained from the attenuation amount of the radio wave intensity by using the following simple expression (3).

  Α and β in Equation (3) are appropriate constants.

  Next, the function of the time series correction processing unit 52 (see FIG. 13) will be described.

  FIG. 21 is a graph for schematically explaining the processing performed by the time series correction processing unit 52, in which the horizontal axis indicates time and the vertical axis indicates radio wave intensity.

Measured value graph C _a in FIG. 21 is a graph of the time series of radio field intensity Obs_P _j where the information processing apparatus 20 has been measured. The ideal graph C _b is a graph of wave intensity Obs_P _j to be expected when there is no influence of multipath fading.

The time series correction processing unit 52 corrects the radio wave intensity obs_P _j for each point P _j so as to eliminate the influence of multipath fading, and outputs the corrected radio wave intensity obs_P _j _Cor.

  22 and 23 are flowcharts showing the processing performed by the time-series correction processing unit 52 in order to perform the correction.

Time series correction processing unit 52, by performing the processing according to this flowchart, as follows correcting field intensity Obs_P _j advertised signals of the transmitter 21.

  This flowchart is performed for each transmitter 21 by the time-series correction processing unit 52 at a cycle of about 40 msec.

Hereinafter, a case where the radio wave intensity of the advertised signal emitted from the transmitter 21 represented by the point P _j is corrected will be described as an example. In addition, the time when this flowchart is actually executed is hereinafter referred to as this time, and the time when this flowchart is executed one cycle before is also referred to as the previous time.

  Then, triggered by the reception of the advertisement signal by the antenna 31 (see FIG. 12), the time-series correction processing unit 52 executes the following steps.

(Step S1)
First, it is determined whether or not the previous measurement value of the radio wave intensity obs_P _j exists in the memory 38.

(Step S2)
If the previous measurement value of the radio field intensity obs_P _j does not exist in the memory 38, the information processing apparatus 20 has measured the radio field intensity obs_P _j for the first time this time. In this case, since there is no criterion for correcting the wave intensity Obs_P _j, and outputs the measured value of the current radio wave strength Obs_P _j as it correction value obs_P _j _Cor.

(Step S3)
If it is determined in step S1 that the previous measurement value of the radio wave intensity obs_P _j exists, it is determined whether or not the current radio wave intensity obs_P _j has suddenly increased.

For example, when the current radio wave intensity obs_P _j is 20 dB or more higher than the previous radio wave intensity obs_P _j, it can be determined that it has suddenly increased.

(Step S4)
If it is determined in step S3 that it has suddenly increased, it is considered that the radio wave intensity has increased due to the presence of a reflector of the radio wave in the vicinity of the information processing apparatus 20, and thus the current radio wave intensity obs_P _j is trusted. Can not. Therefore, the current radio wave intensity obs_P _j is discarded, and the estimated value obtained from the previous radio wave intensity obs_P _j is output as a correction value obs_P _j _Cor.

(Step S5)
If it is determined in step S4 that it has not suddenly increased, it is determined whether or not there is a measured value of the radio wave intensity obs_P _j stored in the memory 38 a predetermined time ago. The fixed time serving as the determination reference is, for example, about 10 seconds.

(Step S6)
If it is determined in step S5 that there is a measurement value of the radio wave intensity obs_P _j accumulated a certain time ago, the peak information of the radio wave intensity obs_P _j before the certain time is deleted. The peak information is information indicating the height and time of the peak and is stored in the memory 38. Since the peak information before the fixed time is not corrected, the consumption of the memory 38 (see FIG. 12) can be suppressed by deleting in this way.

(Step S7)
It is determined whether or not the previous radio wave intensity obs_P _j is located at the peak. For example, when the previous radio wave intensity obs_P _j is stronger than the previous and current radio wave intensity obs_P _j, it is determined that the previous radio wave intensity obs_P _j is located at the peak.

(Step S8)
When the last radio field intensity Obs_P _j is determined to be located in a peak in step S7, the estimated change in the following manner future radio field intensity obs_P _j.

FIG. 24 is a schematic diagram for explaining the estimation method, in which the horizontal axis indicates time and the vertical axis indicates radio wave intensity. This flowchart is executed n times, and the execution time is t _n . The same applies to each drawing described later.

As shown in FIG. 24, it is assumed that the previous (t _n-1 ) radio wave intensity is located at the peak Q ₂ and that there is a peak Q ₁ at any time t _nk before that.

In this case, a straight line L ₁₂ connecting the peak Q ₁ and the peak Q ₂ is drawn, and in the future (t _n , t _{n + 1} , t _{n + 2} ,...), The radio wave intensity obs_P _j is along the straight line L _12. Estimated to change.

  Refer to FIG. 22 again.

(Step S9)
If it is determined in step S7 that the previous radio wave intensity obs_P _j is not located at the peak, a future change in the radio wave intensity obs_P _j is estimated as follows.

  FIG. 25 is a schematic diagram for explaining the estimation method.

In this example, it is assumed that a straight line L ₃₄ connecting two peaks Q ₃ and Q ₄ has already been drawn in step S8 executed before the previous time.

In this case, in this step, and it estimates an RSSI Obs_P _j varies along the curve M past the peak Q _4. The curve M is a curve in which the slope at the peak Q ₄ is the same as that of the straight line L ₃₄ and the slope approaches 0 with time.

Thereby, in this step, the estimated value of the radio wave intensity obs_P _j is prevented from becoming excessively strong.

  Next, description of each process performed by the time-series correction processing unit 52 will be continued with reference to FIG.

(Step S10)
In this step, it is determined whether or not there has been a peak in the past.

(Step S11)
If it is determined in step S10 that there is no peak, it is determined whether or not the measured value of the current radio wave intensity obs_P _j is lower than the previous time.

(Step S12)
And if it is determined low in step S11, there is a possibility that this wave intensity Obs_P _j by multipath fading is weak. Therefore, in this case, the average value of the measured values of the radio field intensity obs_P _j for each of the previous time and the current time is output as the correction value obs_P _j _Cor. Since the correction value obs_P _j _Cor is higher than the current radio wave intensity obs_P _j , the influence of multipath fading can be suppressed.

(Step S13)
If it is determined in step S11 that it is not low, it is considered that the radio field intensity obs_P _j is not affected by multipath fading. Therefore, in this case, the current measured value of the radio wave intensity obs_P _j is output as it is as the correction value obs_P _j _Cor.

(Step S14)
If it is determined that the peak in the past in step S10, to calculate a first estimation value A of the radio wave intensity Obs_P _j as follows.

  FIG. 26 is a schematic diagram for explaining the calculation method.

As shown in FIG. 26, in this step, the newly assumed line K which has been moved parallel to the straight line L ₁₂ described above, the straight line K is to pass through the measurement value of the previous (t _n-1).

A value corresponding to the current time (t _n ) at a point on the straight line K is set as a first estimated value A.

(Step S15)
Next, a second estimated value B of the radio wave intensity obs_P _j is calculated.

  The calculation method will be described with reference to FIG.

In this step, a value corresponding to the current time (t _n ) at a point on the straight line L ₁₂ is set as the second estimated value B.

  Reference is again made to FIG.

(Step S16)
Subsequently, it is determined whether or not the measured value of the current (t _n ) radio wave intensity obs_P _j is lower than the average value of the first estimated value A and the second estimated value B.

(Step S17)
If it is determined in step S16 that it is low, it is considered that the current (t _n ) measured value of the radio wave intensity obs_P _j is low due to multipath fading. Therefore, in this step, the average value of the first estimated value A and the second estimated value B is output as the correction value obs_P _j _Cor.

(Step S18)
If it is determined to be low in step S16, it is considered an RSSI Obs_P _j tends to increase.

Therefore, in this step, the change in the radio field intensity is increased by increasing the slope of the straight line L ₁₂ passing through the previous peak Q ₂ (see FIG. 24).

(Step S19)
Thereafter, the current (t _n ) radio wave intensity obs_P _j is output as a correction value obs_P _j _Cor.

  Thus, the process performed by the time series correction processing unit 52 is completed.

FIG. 27 is a schematic diagram of a correction graph C ₀ in which the correction value obs_P _j _Cor is graphed. As shown in the drawing, the correction graph C ₀ is wave intensity as compared to the measured graph C _a has become less time to unduly decrease the influence of multipath fading is suppressed.

By performing positioning using the correction value obs_P _j _Cor corrected in this way, it is possible to suppress a decrease in positioning accuracy due to multipath fading.

  The function of the time series correction processing unit 52 is not limited to the above.

For example, without the process of FIGS. 22 23 described above, provided the peak hold circuit for holding a peak of the measurement chart C _a as time series correction processing unit 52, a time series correction processing unit 52 outputs the value of the peak May be.

<Information processing method>
Next, an information processing method according to the present embodiment will be described.

  FIG. 28 is a flowchart for explaining the information processing method according to the present embodiment.

In the following, it is assumed that n transmitters 21 represented by points P _{0 to} P _n−1 are fixed indoors.

(Step S30)
First, the radio wave intensity input unit 51 measures the radio wave intensity obs_P _{0 to} obs_P _n−1 of the advertised signal of each of the n transmitters 21.

(Step S31)
Next, the time-series correction processing unit 52 corrects each of the radio wave intensities obs_P _{0 to} obs_P _n−1 according to the flowcharts of FIGS. 22 and 23 described above.

(Step S32)
Next, the attenuation amount correction processing unit 58 corrects the attenuation amounts att_P _{0 to} att_P _k .

  The correction is performed according to the correction method described with reference to FIGS.

For example, when the triangle P ₁ P ₂ P ₃ includes the point P ₀ and att_P ₀ > Max (att_P ₁ , att_P ₂ , att_P ₃ ), the attenuation correction processing unit 58 uses att_P ₀ = Max Att_P ₀ is corrected so that (att_P ₁ , att_P ₂ , att_P ₃ ).

Even when the triangle P ₁ P ₂ P ₃ includes the point P ₀ , if att_P ₀ ≦ Max (att_P ₁ , att_P ₂ , att_P ₃ ), the attenuation correction processing unit 58 sets the att_P ₀ Do not correct the value.

In addition, the points P _i (0 ≦ i ≦ k) to be corrected in this way are points P _{0 to} P determined by the inclusion determination unit 57 when included in a triangle formed by the three surrounding points. _k . The notification that these points P _{0 to} P _k are included in the triangle is notified in advance from the inclusion determination unit 57 to the attenuation correction processing unit 58 before the execution of this step.

In addition, before the determination by the inclusion determination unit 57, the transmitters far from the own device among the n transmitters 21 represented by the points P _{0 to} P _n−1 by the beacon candidate clip unit 55 are excluded in advance. The points P _{0 to} P _k that have been excluded and are not excluded are subject to determination by the inclusion determination unit 57 as described above.

(Step S33)
Next, the radio wave intensity accumulating unit 54 creates an attenuation table 59 (see FIG. 18) indicating values of att_P _{0 to} att_P _k at each time, and stores the attenuation table 59 in the memory 37.

If there is one of the attenuation amounts att_P _{0 to} att_P _k that has been corrected in step S 32, the radio wave intensity accumulating unit 54 accumulates the corrected attenuation amount in the attenuation amount table 59.

(Step S34)
Subsequently, the position estimation unit 55 estimates the position of the own device at the time using the values of the attenuation amounts att_P _{0 to} att_P _{k at} the same time.

For example, the position estimation unit 55 acquires weights W ₀ , W ₂ ,... W _k corresponding to the attenuation amounts att_P _{0 to} att_P _k from the correlation table 60 (see FIG. 19), Calculate the position coordinates (X, Y) of the device.

  After that, the position estimation unit 55 notifies the beacon candidate clip unit 56 of the position coordinates of the own device calculated in this way. Then, the beacon candidate clip unit 56 uses the notified position coordinates of the own device, and excludes the transmitter 21 located far away from the own device as shown in FIGS. 15 and 16.

  Thus, the basic steps of the information processing method according to this embodiment are finished.

According to the information processing method described above, when att_P ₀ > Max (att_P ₁ , att_P ₂ , att_P ₃ ) due to multipath fading as shown in FIGS. 9 to 11, att_P ₀ = Max The attenuation amount att_P ₀ is corrected so as to be (att_P ₁ , att_P ₂ , att_P ₃ ).

Thereby, since the influence of multipath fading is excluded from the value of att_P ₀ , the accuracy of the position of the information processing apparatus 20 calculated from each attenuation amount att_P _{0 to} att_P ₃ is increased.

In addition, since the attenuation amount att_P ₀ is simply reduced, the information processing apparatus 20 that lacks calculation resources can determine the position of the own apparatus with high accuracy.

(Second Embodiment)
In the first embodiment, as described with reference to FIGS. 9 to 11, the attenuation amount correction processing unit 58 sets the attenuation amount att_P ₀ so that Max (att_P ₁ , att_P ₂ , att_P ₃ ) = att_P _0. Corrected.

  In the present embodiment, correction is performed by a different method.

  29 to 32 are schematic diagrams for explaining the correction method according to the present embodiment. In these drawings, the same elements as those described in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description thereof is omitted below.

In the present embodiment, as shown in FIG. 29, it is assumed that the transmitter 21 to each point P ₁ to P ₃ is fixed. The attenuation amounts at the time when the advertised signals transmitted from these transmitters 21 reach the information processing apparatus 20 are assumed to be att_P _{1 to} att_P ₃ .

Then, as shown in FIG. 30, it is assumed that the transmitter 21 exists also at a point P ₀ included in the triangle P ₁ P ₂ P ₃ . As in the first embodiment, and all radio intensity ori_P ₀ ~ori_P ₃ of advertising signal just emitted from each of the transmitter 21 of the point P ₀ to P ₃ are the same. Further, the distance between the point P _i and the point P ₀ is written as d _i0 .

At this time, assuming that the estimated value of the attenuation of the radio field intensity of the advertised signal emitted from the transmitter 21 at the point P ₀ is att_P ₀ _Est, the estimated value att_P ₀ _Est is attenuated with the distances d ₁₀ , d ₂₀ , and d _30. It depends on the amount att_P ₁ ~att_P _3.

For example, the smaller the distance d ₁₀ between the point P ₁ and the point P _0, the estimate att_P ₀ _Est becomes a value close to att_P _1. Further, if the distance d ₂₀ between the point P ₂ and the point P ₀ is large, the estimated value att_P ₀ _Est becomes a value greatly different from att_P ₂ .

Therefore, in this embodiment, the estimated value att_P ₀ _Est is estimated according to the following equation (5).

According to the equation (5), the estimated value att_P ₀ _Est is equal to a value obtained by averaging the attenuation amounts att_P _{1 to} att_P ₃ using the reciprocals of the distances d ₁₀ , d ₂₀ , and d ₃₀ as weights.

The estimated value att_P ₀ _Est can be described geometrically as follows.

As shown in FIG. 30, consider virtual bars having heights obs_P ₁ , obs_P ₂ , and obs_P ₃ at points P _{1 to} P ₃ , and consider a triangle V stretched at the vertices of these bars. Also, consider the virtual bars of obs_P ₁ + att_P ₁ , obs_P ₂ + att_P ₂ , obs_P ₃ + att_P _{3 at} the points P _{1 to} P ₃ , and the triangle W stretched at the vertices of these bars Think.

At this time, the distance between the intersection point p ₁ between the straight line Z extending upward from the point P ₀ and the triangle V and the intersection point p ₂ between the straight line Z and the triangle W is the estimated value att_P ₀ _Est.
FIG. 31 is a schematic diagram when the information processing apparatus 20 measures the attenuation amount att_P ₀ of the radio wave intensity of the advertised signal emitted from the transmitter 21 installed at the point P ₀ . The position of the information processing apparatus 20 is not particularly limited, and the information processing apparatus 20 may be located anywhere inside and outside the triangle P ₁ P ₂ P ₃ .

In the example of FIG. 31, the attenuation amount att_P ₀ is larger than the estimated value att_P ₀ _Est. In this case, it is considered that the attenuation amount att_P ₀ has increased due to multipath fading.

Therefore, in this case, as shown in FIG. 32, the attenuation amount correction processing unit 58 performs correction to reduce the value of the attenuation amount att_P ₀ so that the attenuation amount att_P ₀ becomes equal to the estimated value att_P ₀ _Est.

If the attenuation amount att_P ₀ is equal to or less than the estimated value att_P ₀ _Est, the attenuation amount correction processing unit 58 does not correct the attenuation amount att_P ₀ .

According to the embodiment described above, in order to correct the attenuation Att_P ₀ based on the respective distances d _10, d _20, d ₃₀ and attenuation att_P ₁ ~att_P _3, only the attenuation att_P ₁ ~att_P ₃ The accuracy of correction is improved compared with the case of using.

In the present embodiment, the case where the point P ₀ is included in the triangle P ₁ P ₂ P ₃ as described above is described as an example, but the present embodiment is not limited to this.

  FIG. 33 is a schematic diagram for explaining a correction method according to another example of the present embodiment.

In this example, it is assumed that the points P ₀ , P ₁ and P ₂ are aligned on a straight line L.

In this case, the estimated value att_P ₀ _Est is estimated according to the following equation (6) by analogy with equation (5).

When the attenuation amount att_P ₀ is larger than the estimated value att_P ₀ _Est, the attenuation amount correction processing unit 58 corrects the attenuation amount att_P ₀ so that att_P ₀ _Est = att_P ₀ .

(Third embodiment)
In the present embodiment, the attenuation is corrected using a link node map as follows.

  FIG. 34 is a functional configuration diagram of the information processing apparatus 20 according to the present embodiment.

  In FIG. 34, the same elements as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and description thereof will be omitted below.

  As shown in FIG. 34, in the present embodiment, the correction unit 53 does not include the inclusion determination unit 57 (see FIG. 13) described in the first embodiment. The functional configuration other than this is the same as that of the first embodiment.

  FIG. 35 is a schematic diagram of a link node map 60 used by the correction unit 53 in the present embodiment.

This link node map 60 is the same as that used by the beacon candidate clip unit 56, and each transmitter 21 represented by the points P ₀ and P ₁ and the information processing device 20 at the point A are attached with cost. It is a map connected by the link.

  FIG. 36 is a schematic diagram for explaining a correction method in the present embodiment.

In this example, it is assumed that point A and point P ₀ are connected by link L ₀ and point P ₀ and point P ₁ are connected by link L ₁ .

Incidentally, the cost C _0, C ₁ of each of the links L _0, L ₁ may be a respective physical length of the link L _0, L _1, it may be fixed to a constant value "1". These costs C ₀ and C ₁ are stored in the memory 38 in advance.

In this case, when the point P ₀ is close to the point P ₁ , the attenuation of the radio wave intensity of the advertised signal emitted from the transmitter 21 at the point P ₀ becomes close to that at P ₁ . Further, when the point P ₀ is close to the point A, the attenuation amount of the radio wave intensity of the advertised signal emitted from the transmitter 21 at the point P ₀ becomes close to zero.

Therefore, in the present embodiment, the attenuation correction processing unit 58 refers to the memory 38 to obtain the costs C ₀ and C _1, and the advertisement signal generated by the transmitter 21 at the point P ₀ according to the following equation (7). Estimate the attenuation value att_P ₀ _Est of the radio field intensity.

By multiplying the attenuation Att_P ₁ to the value obtained by dividing the cost _{C 0 C 0 / (C 0} + C 1) by the sum of the cost C _0, C ₁ as equation (7), considering the cost of each link Thus, the estimated value att_P ₀ _Est can be estimated.

FIG. 37 is a schematic diagram when the actual attenuation amount att_P ₀ is larger than the estimated value att_P ₀ _Est. In this case, it is considered that the attenuation amount att_P ₀ is larger than actual due to multipath fading.

Therefore, in this case, as shown in FIG. 38, att_P ₀ = att_P ₀ attenuation correction processing unit 58 so that _Est is a correction to reduce the attenuation att_P _0.

When the actual attenuation amount att_P ₀ is equal to or less than the estimated value att_P ₀ _Est, it is considered that the attenuation amount att_P ₀ is not affected by multipath fading. In this case, the attenuation amount correction processing unit 58 Attenuation amount att_P ₀ is not corrected.

According to the present embodiment described above, since the attenuation amount att_P ₀ is corrected in consideration of the cost of the link, the correction accuracy can be improved as compared with the case where correction is performed using only the attenuation amount att_P ₁ .

  The following additional notes are disclosed for each embodiment described above.

(Supplementary note 1) One of a plurality of transmitters is closer to its own device than another transmitter, and the attenuation amount of the radio field intensity of the one transmitter is the other transmitter. A correction unit that performs correction to reduce the attenuation amount of the one transmitter when the attenuation amount of the radio field intensity is greater than
A position estimation unit that estimates the position of the device using the corrected attenuation amount;
An information processing apparatus.

(Supplementary Note 2) When the one transmitter is included in a triangle having three of the plurality of transmitters as vertices,
2. The information processing according to claim 1, wherein the correction unit corrects the attenuation amount of the one transmitter so as to be equal to a maximum value of the attenuation amounts of the three transmitters. apparatus.

(Supplementary Note 3) When the one transmitter is included in a triangle having three of the plurality of transmitters as vertices,
The correction unit weights the reciprocal of the distance between each of the three transmitters and the one transmitter to give a weight equal to an average value of the attenuation amounts of the three transmitters. The information processing apparatus according to appendix 1, wherein the attenuation amount of the transmitter is corrected.

(Supplementary Note 4) The correction unit is
The correction amount of the one transmitter is corrected based on the cost by using a link node map in which the own device and each of the plurality of transmitters are connected by a link with a cost. The information processing apparatus according to 1.

(Additional remark 5) The said correction | amendment part is
Determining a first cost of the link connecting the own apparatus and the one transmitter and a second cost of the link connecting the one transmitter and the other transmitter;
The attenuation amount is corrected by multiplying the value obtained by dividing the first cost by the sum of the first cost and the second cost by the attenuation amount of the one transmitter. The information processing apparatus according to appendix 4.

  (Additional remark 6) The said correction | amendment part does not use the said attenuation amount of the said excluded transmitter for the said correction | amendment by excluding the said transmitter from which the sum total of the said cost as a starting point becomes more than a regulation value. The information processing apparatus according to appendix 4, characterized by:

  (Additional remark 7) The said correction | amendment part does not use the said attenuation amount of the said excluded transmitter for the said correction | amendment by excluding the said transmitter which is not directly connected with an own apparatus with the said link. 5. The information processing apparatus according to 4.

(Appendix 8) In the information processing device,
The transmitter of one of the plurality of transmitters is closer to the information processing device than the other transmitter, and the attenuation of the radio field intensity of the one transmitter is the radio wave of the other transmitter When it is larger than the attenuation amount of the intensity, a correction is made to reduce the attenuation amount of the one transmitter.
Estimating the position of the information processing device using the corrected attenuation amount;
An information processing program for executing processing.

(Supplementary note 9) An information processing method executed by an information processing apparatus, wherein the information processing apparatus
The transmitter of one of the plurality of transmitters is closer to the information processing device than the other transmitter, and the attenuation of the radio field intensity of the one transmitter is the radio wave of the other transmitter When it is larger than the attenuation amount of the intensity, a correction is made to reduce the attenuation amount of the one transmitter.
Estimating the position of the information processing apparatus using the corrected attenuation amount;
An information processing method characterized by the above.

DESCRIPTION OF SYMBOLS 1 ... System 3, 20 ... Information processing apparatus 4, 21 ... Transmitter, 23 ... Indoor, 28 ... Ceiling, 31 ... Antenna, 32 ... Radio part, 33 ... Acceleration sensor, 34 ... Gyro sensor, 35 ... Geomagnetic sensor , 36 ... storage unit, 37 ... processor, 38 ... memory, 51 ... radio wave intensity input unit, 52 ... time series correction processing unit, 53 ... correction unit, 54 ... radio wave intensity storage unit, 55 ... position estimation unit, 56 ... beacon Candidate clip part, 57 ... inclusion determination part, 58 ... attenuation amount correction processing part.

Claims (5)

The transmitter of one of the plurality of transmitters is closer to its own device than the other transmitter, and the attenuation of the radio field intensity of the one transmitter is equal to the radio field intensity of the other transmitter. A correction unit that performs correction to reduce the attenuation amount of the one transmitter when the attenuation amount is larger than the attenuation amount;
A position estimation unit that estimates the position of the device using the corrected attenuation amount;
An information processing apparatus. When the one transmitter is included in a triangle having a vertex of three of the plurality of transmitters,
The information according to claim 1, wherein the correction unit corrects the attenuation amount of the one transmitter so as to be equal to a maximum value of the attenuation amounts of the three transmitters. Processing equipment. The correction unit is
The attenuation amount of the one transmitter is corrected based on the cost by using a link node map in which the own apparatus and each of the plurality of transmitters are connected by a link with a cost. Item 4. The information processing apparatus according to Item 1. In the information processing device,
The transmitter of one of the plurality of transmitters is closer to the information processing device than the other transmitter, and the attenuation of the radio field intensity of the one transmitter is the radio wave of the other transmitter When it is larger than the attenuation amount of the intensity, a correction is made to reduce the attenuation amount of the one transmitter.
Estimating the position of the information processing device using the corrected attenuation amount;
An information processing program for executing processing. An information processing method executed by an information processing apparatus, wherein the information processing apparatus comprises:
The transmitter of one of the plurality of transmitters is closer to the information processing device than the other transmitter, and the attenuation of the radio field intensity of the one transmitter is the radio wave of the other transmitter When it is larger than the attenuation amount of the intensity, a correction is made to reduce the attenuation amount of the one transmitter.
Estimating the position of the information processing apparatus using the corrected attenuation amount;
An information processing method characterized by the above.

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