JP5571347B2 - Position searching apparatus and position searching method - Google Patents

Description

  The present invention relates to a position search device and a position search device that search for the position of a radio wave transmitter that transmits radio waves.

In recent years, sensor network-related technologies have attracted attention due to the increasing demand for a ubiquitous society. In this sensor network related technology, many sensor terminals for collecting environmental information and actuator terminals for controlling devices are distributed in the field and connected to each other through a network to process and control information. It is expected to be applicable to various situations such as welfare and transportation.
As a function for realizing an application for a ubiquitous society, a positioning function (estimating or detecting the position of a terminal) that searches for the position of a person or an object can be said to be the most useful. Examples thereof include a navigation system using GPS (Global Positioning System) and an article management system using a wireless tag.
This GPS is a system that can realize its own positioning with high accuracy everywhere on the earth. However, if it is not possible to use indoors where radio waves from satellites cannot be received, the module is expensive, or if you want to use location information outside the vicinity of the person or thing you want to measure, it will take time to retrieve the positioning result via the network once There are difficulties such as.

  On the other hand, it is considered that the position information desired to be used in the sensor network or the wireless tag system is often the position information of things. For example, there are position detection of a mobile communication terminal such as a mobile phone (for example, see Patent Document 1), position detection of a wireless tag attached for article management (for example, see Patent Document 2), and the like.

Here, a conventional position search system will be described with reference to FIG. FIG. 12 is a schematic diagram illustrating an example of a conventional position search system.
As shown in FIG. 12, the conventional position search system includes a radio wave transmission device 910 that transmits radio waves and a plurality of radio wave characteristic acquisition devices 930 (930-1) that acquire radio wave characteristics of radio waves transmitted from the radio wave transmission device 910. 930-12), a position database 970 in which position information indicating the position of the radio wave characteristic acquisition device 930 measured in advance is recorded, and an estimated position of the radio wave transmission device 910 is calculated based on the radio wave characteristics and the position information. The estimated position calculation apparatus 950 is comprised.
In this position search system, a radio signal transmitted from the radio wave transmission device 910 is received by the radio wave characteristic acquisition device 930, and radio wave characteristic information such as electric field strength, radio wave arrival angle, radio wave propagation time, and the like, Based on the measured position information of the plurality of radio wave characteristic acquisition apparatuses 930, the estimated position calculation apparatus 950 estimates the position of the radio wave transmission apparatus 910.
The estimated position calculation device 950 uses, for example, the characteristic that the radio wave characteristic changes according to the relative distance between the radio wave transmission apparatus 910 and each of the plurality of radio wave characteristic acquisition apparatuses 930, and determines the position of the radio wave transmission apparatus 910. presume.

Japanese Patent Application Laid-Open No. 07-231473 Japanese Patent Laid-Open No. 2004-53510

  However, in various conventional methods that perform positioning using various radio wave characteristics acquired by a plurality of radio wave characteristic acquisition devices 930 as described with reference to FIG. 12, the position and number of the radio wave characteristic acquisition devices 930 are generally determined in advance. It has been. Therefore, the positioning accuracy of the radio wave transmission device 910 obtained in the position search system is uniquely determined. However, if the distance between the plurality of radio wave characteristic acquisition devices 930 and the radio wave transmission device 910 is long, the positioning accuracy deteriorates, and the radio wave characteristic acquisition device 930 is obtained. When the radio wave transmission device 910 is outside the range in which the radio wave characteristics can be acquired, the position of the radio wave transmission device 910 cannot be measured.

  Further, in order to solve the above-described degradation of positioning information, etc., it can be solved by increasing the number of radio wave characteristic acquisition devices 930. However, since the position of the radio wave transmission device 910 that is a positioning target is not known in advance, positioning is performed. In order to improve accuracy, it is necessary to install an enormous number of radio wave characteristic acquisition devices 930, and there is a problem that it takes time and cost.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a position search device and a position search method that improve the positioning accuracy of a radio wave transmission device without increasing the number of radio wave characteristic acquisition devices. It is to provide.

In order to solve the above-described problem, the present invention is a position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device, and the radio wave of the radio wave transmitted by the radio wave transmission device A radio wave characteristic acquisition device for detecting radio wave characteristic information representing characteristics; a position acquisition device for detecting position information representing a position of the position search device; and the position search device based on the radio wave characteristic information and the position information. An estimated position calculation device that calculates estimated position information that is information indicating a moving direction from a certain position toward the radio wave transmitting device, and determines the moving direction of the position search device based on the estimated position information, and this movement generates notification information indicating a direction, and a movement route determining device for outputting the notification information to the notification unit provided in the movable body, the locator When the plurality of radio wave characteristic information detected by the radio wave characteristic acquisition device and each of the plurality of radio wave characteristic information are detected on the moving path of the mobile body by being mounted on the moving body, The estimated position information is calculated based on a plurality of the position information detected by the position acquisition device, and the estimated position calculation device transmits each propagation distance from the plurality of radio wave characteristic information detected by the radio wave characteristic acquisition device. Using the variance of the value obtained by subtracting the attenuation equivalent amount, the existence probability distribution representing the probability that the radio wave transmission device exists is calculated as the estimated position information, and the movement path determination device is based on the existence probability distribution, The area of the region where the evaluation function for evaluating the existence probability of the radio wave transmitting device is smaller than the first threshold value is calculated, and the calculated area is equal to or less than the second threshold value. Determining whether a, if the is calculated area is not less than the second threshold value, it outputs the notification information indicating that moves in a direction to move to the area the evaluation function is small the notification unit This is a position search device characterized by the above.

The present invention is a position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device, and detects radio wave characteristic information representing a radio wave characteristic of the radio wave transmitted by the radio wave transmission device. Based on the radio wave characteristic acquisition apparatus, the position acquisition apparatus that detects position information indicating the position of the position search apparatus, and the radio wave characteristic information and the position information, the position search apparatus heads from the current position to the radio wave transmission apparatus. An estimated position calculation device that calculates estimated position information that is information indicating a moving direction, and determines a moving direction of the position search device based on the estimated position information, and generates notification information representing the moving direction, The radio wave characteristic information is detected by a movement path determination device that outputs the notification information to a notification unit provided in the mobile body and the radio wave characteristic acquisition device. A time acquisition device that detects time information representing time, and the position information detected by the position search device when the radio wave characteristic information is detected with respect to the radio wave characteristic information, the radio wave characteristic information is detected. A storage unit that stores the time information representing time and the radio wave characteristic information and the estimated position information calculated based on the position information in association with each other, and the position search device is mounted on a moving body and moves Thus, the position acquisition device detects the plurality of radio wave characteristic information detected by the radio wave characteristic acquisition device and the plurality of radio wave characteristic information in the moving path of the mobile body. The estimated position information is calculated based on a plurality of the position information, and the movement path determination device is configured to detect the position detected by the position search device. Of the differences between each of the reports and the estimated position information associated with the newest time information among the estimated information, the smallest difference is determined in advance as a value allowed as a search result of the radio wave transmitter. It is determined whether or not the target positioning accuracy is less than or equal to the target positioning accuracy, and the estimated position represented by the difference between the estimated position information associated with the newest time information and the estimated position information associated with the second most recent time information It is determined whether or not the movement amount is equal to or less than a predetermined third threshold, and when the minimum difference is larger than the target positioning accuracy, or the movement amount of the transition position is the third threshold. In the case of being larger, or in both cases, the movement is in the direction approaching the estimated position represented by the estimated position information associated with the latest time information. The position search apparatus is characterized in that notification information is output to the notification unit.

According to the present invention, in the above invention, the estimated position calculation device is an estimated position where a variance of a value obtained by subtracting a propagation distance attenuation equivalent amount from a plurality of pieces of radio wave characteristic information detected by the radio wave characteristic acquisition device is minimized. Is calculated as the estimated position information.

The present invention is a position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device, and detects radio wave characteristic information representing a radio wave characteristic of the radio wave transmitted by the radio wave transmission device. Based on the radio wave characteristic acquisition apparatus, the position acquisition apparatus that detects position information indicating the position of the position search apparatus, and the radio wave characteristic information and the position information, the position search apparatus heads from the current position to the radio wave transmission apparatus. An estimated position calculation device that calculates estimated position information that is information indicating a moving direction, and determines a moving direction of the position search device based on the estimated position information, and generates notification information representing the moving direction, The radio wave characteristic information is detected by a movement path determination device that outputs the notification information to a notification unit provided in the mobile body and the radio wave characteristic acquisition device. A time acquisition device that detects time information representing time, and the position information detected by the position search device when the radio wave characteristic information is detected with respect to the radio wave characteristic information, the radio wave characteristic information is detected. A storage unit that stores the time information representing time and the radio wave characteristic information and the estimated position information calculated based on the position information in association with each other, and the position search device is mounted on a moving body and moves Thus, the position acquisition device detects the plurality of radio wave characteristic information detected by the radio wave characteristic acquisition device and the plurality of radio wave characteristic information in the moving path of the mobile body. The estimated position information is calculated based on a plurality of the position information, and the movement route determination device is configured to detect position information associated with the latest time information. The amount of change in the measurement position represented by the difference between the position information associated with the second new time information, the estimated position information associated with the newest time information, and the estimated position information associated with the second new time information. And the change amount of the estimated position represented by the difference between the measurement position and the change amount of the measurement position is determined to be greater than or equal to the change amount of the estimated position. If the change amount is not equal to or greater than the change amount, the notification information indicating that the current traveling direction is maintained is output to the notification unit. Of the differences between the position information detected by the search device and the estimated position information associated with the newest time information among the estimated information, the smallest difference is the search for the radio wave transmitting device. As a result, it is determined whether or not the target positioning accuracy is less than or equal to a predetermined target positioning accuracy, and the estimated position information associated with the newest time information is associated with the second newest time information. Determining whether or not the amount of movement of the estimated position represented by the difference from the estimated position information is equal to or less than a predetermined fourth threshold, and the minimum difference is greater than the target positioning accuracy, or When the moving amount of the transition position is larger than the fourth threshold value, or both, it represents that the moving position moves closer to the estimated position represented by the estimated position information associated with the newest time information. The notification information is output to the notification unit, the minimum difference is not more than the target positioning accuracy, and the movement amount of the transition position is not more than the fourth threshold value. In this case, the surrounding area of the estimated position represented by the estimated position information associated with the latest time information is equally divided by a predetermined number, and the position information is detected in each of the equally divided divided surrounding areas. If at least one of the position information is not detected in all of the divided surrounding areas, the position is calculated from the estimated position represented by the estimated position information associated with the latest time information. A position search apparatus that outputs notification information indicating movement in a direction toward the divided peripheral area where no information is detected.
According to the present invention, in the above invention, the estimated position calculation device uses a plurality of pieces of radio wave characteristic information detected by the radio wave characteristic acquisition device, and each time the position acquisition device detects each position information. Weighting is performed on the center of gravity, and the position of the center of gravity is calculated and updated as the estimated position information.

According to the present invention, in the above invention, a moving direction of the position search device is determined based on the estimated position information, and notification information indicating the moving direction is generated, and a notification unit provided in the moving body is provided. The apparatus further includes a movement route determination device that outputs the notification information .

The present invention is a position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device, and detects radio wave characteristic information representing a radio wave characteristic of the radio wave transmitted by the radio wave transmission device. A radio wave characteristic acquisition apparatus; a position acquisition apparatus that detects position information representing the position of the position search apparatus; and a position predicted as a position of the radio wave transmission apparatus that is a search target based on the radio wave characteristic information and the position information An estimated position calculation device for calculating estimated position information representing the position of the position search device, and a moving direction of the position search device is determined based on the estimated position information, and notification information representing the moving direction is generated and provided in the moving body. A moving path determination device that outputs the notification information to a notification unit, and the position search device is mounted on the moving body and moved, thereby moving the moving body Based on the radio wave characteristic information detected by the radio wave characteristic acquisition device in the movement path and the position information detected by the position acquisition device when the radio wave characteristic information is detected, the estimated position information is calculated, The estimated position calculation device uses a variance of a value obtained by subtracting a propagation distance attenuation equivalent amount from the radio wave characteristic information detected by the radio wave characteristic acquisition device, and an existence probability distribution representing the probability that the radio wave transmission device exists, Calculated as the estimated position information, the movement path determination device, based on the presence probability distribution, calculates the area of the region where the evaluation function for evaluating the presence probability of the radio wave transmission device is smaller than a first threshold, It is determined whether or not the calculated area is equal to or greater than a second threshold value, and when the calculated area is equal to or greater than the second threshold value, the evaluation function is small. A locator, characterized in that the notification information indicating that moves in a direction to move output to the notification portion.

The present invention is a position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device, and detects radio wave characteristic information representing a radio wave characteristic of the radio wave transmitted by the radio wave transmission device. A radio wave characteristic acquisition apparatus; a position acquisition apparatus that detects position information representing the position of the position search apparatus; and a position predicted as a position of the radio wave transmission apparatus that is a search target based on the radio wave characteristic information and the position information An estimated position calculation device for calculating estimated position information representing the position of the position search device, and a moving direction of the position search device is determined based on the estimated position information, and notification information representing the moving direction is generated and provided in the moving body. A moving path determination device that outputs the notification information to a notification unit, and time information representing a time when the radio wave characteristic information is detected by the radio wave characteristic acquisition device A time acquisition device to detect, and the position information detected by the position search device when the radio wave characteristic information is detected with respect to the radio wave characteristic information, and the time information indicating the time when the radio wave characteristic information is detected And a storage unit that stores the radio wave characteristic information and the estimated position information calculated based on the position information in association with each other, and the position search device is mounted on a moving body and moved. Based on the radio wave characteristic information detected by the radio wave characteristic acquisition device in the moving path of the moving body and the position information detected by the position acquisition device when the radio wave characteristic information is detected, the estimated position information is And the moving route determination device calculates each of the position information detected by the position search device and the latest time of the estimation information. In addition to determining whether the smallest difference among the differences from the estimated position information associated with the report is equal to or less than a target positioning accuracy that is predetermined as a value allowed as a search result of the radio wave transmitting device The movement amount of the estimated position represented by the difference between the estimated position information associated with the newest time information and the estimated position information associated with the second most recent time information is equal to or less than a third threshold value determined in advance. If the minimum difference is larger than the target positioning accuracy, or the movement amount of the transition position is larger than the third threshold, or both, the newest Outputting notification information indicating moving in a direction approaching an estimated position represented by estimated position information associated with time information to the notification unit It is a position search device.

The present invention is a position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device, and detects radio wave characteristic information representing a radio wave characteristic of the radio wave transmitted by the radio wave transmission device. A radio wave characteristic acquisition apparatus; a position acquisition apparatus that detects position information representing the position of the position search apparatus; and a position predicted as a position of the radio wave transmission apparatus that is a search target based on the radio wave characteristic information and the position information An estimated position calculation device for calculating estimated position information representing the position of the position search device, and a moving direction of the position search device is determined based on the estimated position information, and notification information representing the moving direction is generated and provided in the moving body. A moving path determination device that outputs the notification information to a notification unit, and time information representing a time when the radio wave characteristic information is detected by the radio wave characteristic acquisition device A time acquisition device to detect, and the position information detected by the position search device when the radio wave characteristic information is detected with respect to the radio wave characteristic information, and the time information indicating the time when the radio wave characteristic information is detected And a storage unit that stores the radio wave characteristic information and the estimated position information calculated based on the position information in association with each other, and the position search device is mounted on a moving body and moved. Based on the radio wave characteristic information detected by the radio wave characteristic acquisition device in the moving path of the moving body and the position information detected by the position acquisition device when the radio wave characteristic information is detected, the estimated position information is The movement route determination device calculates the position information associated with the newest time information and the position information associated with the second newest time information. The amount of change in the measured position represented by the difference is compared with the amount of change in the estimated position represented by the difference between the estimated position information associated with the newest time information and the estimated position information associated with the second most recent time information. Then, it is determined whether or not the change amount of the measurement position is greater than or equal to the change amount of the estimated position. If the change amount of the measurement position is not greater than or equal to the change amount of the estimated position, the current traveling direction is maintained. Each of the position information detected by the position search device, when the change amount of the measurement position is equal to or greater than the change amount of the estimated position, Among the estimated information, a target that is determined in advance as a value allowed as a search result of the radio wave transmitting device is the smallest difference among the differences from the estimated position information associated with the latest time information. It is determined whether or not the positioning accuracy is below, and the estimated position represented by the difference between the estimated position information associated with the newest time information and the estimated position information associated with the second most recent time information is moved It is determined whether or not the amount is less than or equal to a predetermined fourth threshold, and if the minimum difference is greater than the target positioning accuracy, or the amount of movement of the transition position is greater than the fourth threshold In the case of being large, or in both cases, the notification information indicating movement in the direction approaching the estimated position represented by the estimated position information associated with the latest time information is output to the notification unit, and the minimum Is the estimated position associated with the newest time information when the difference is less than or equal to the target positioning accuracy and the movement amount of the transition position is less than or equal to the fourth threshold value. The surrounding area of the estimated position represented by the information is equally divided by a predetermined number, and it is determined whether or not the position information is detected in each of the equally divided divided surrounding areas. When at least one of the position information is not detected in all, the direction from the estimated position represented by the estimated position information associated with the newest time information to the divided surrounding area where the position information is not detected The position search apparatus is characterized in that it outputs notification information indicating that the mobile station is moving.

In order to solve the above-described problem, the present invention provides a position search method by a position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device, the position search device The radio wave characteristic acquisition device detects radio wave characteristic information representing the radio wave characteristic of the radio wave transmitted by the radio wave transmission device, and the position search device detects the radio wave characteristic information when the position acquisition device of the position search device detects the radio wave characteristic information. Position information representing an existing position is detected, and the estimated position calculation device of the position search device represents a position predicted as the position of the radio wave transmission device to be searched based on the radio wave characteristic information and the position information. when calculating the estimated position information by using the dispersion of the propagation distance attenuation amount equivalent value obtained by subtracting from the radio wave characteristic information detected by the wave characteristic acquisition device, the radio signal transmitting The presence probability distribution representing the probability that location exists, calculated as the estimated position information, the position search apparatus, by being moved is mounted on a mobile object, the radio wave characteristic acquisition device in the moving path of the moving body and the radio wave characteristic information detected by, based on the prior SL position information that will be detected by the position acquisition device when detecting an equivalent electric wave characteristic information, calculates the estimated position information, the position search unit The movement path determination device determines a movement direction of the position search device based on the estimated position information, generates notification information indicating the movement direction, and notifies the notification unit included in the moving body of the notification. When outputting information, based on the existence probability distribution, an area of an area in which an evaluation function for evaluating the existence probability of the radio wave transmitting device is smaller than a first threshold value is calculated. A notification indicating that the evaluation function moves in a direction of moving to a smaller area if the calculated area is greater than or equal to the second threshold. The position search method is characterized in that information is output to the notification unit .
The present invention relates to a position search method by a position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device, wherein the radio wave characteristic acquisition device of the position search device is the radio wave transmission device. Detecting the radio wave characteristic information representing the radio wave characteristic of the radio wave transmitted by the position search device, and detecting the position information indicating the position where the position search device exists when the position acquisition device of the position search device detects the radio wave characteristic information, A time acquisition device of the position search device detects time information indicating a time when the radio wave characteristic information is detected by the radio wave characteristic acquisition device, and the position search device detects the radio wave characteristic with respect to the radio wave characteristic information. The position information detected by the position search device when the information is detected, the time information indicating the time when the radio wave characteristic information is detected, and the radio wave characteristic information. And the estimated position information calculated based on the position information are stored in association with each other, and the estimated position calculation device of the position search device is the search object based on the radio wave characteristic information and the position information. The estimated position information representing the predicted position is calculated, and the position search device is detected by the radio wave characteristic acquisition device in the moving path of the moving body by being mounted on the moving body and moving. Based on the radio wave characteristic information and the position information detected by the position acquisition device when the radio wave characteristic information is detected, the estimated position information is calculated, and the movement path determination device of the position search device includes: The moving direction of the position search device is determined based on the estimated position information, and notification information indicating the moving direction is generated and provided in the moving body. When the notification information is output to the notification unit, the minimum of the differences between each of the position information detected by the position search device and the estimated position information associated with the newest time information among the estimated information And whether or not the difference is equal to or less than a target positioning accuracy predetermined as a value allowed as a search result of the radio wave transmitter, estimated position information associated with the newest time information, It is determined whether or not the amount of movement of the estimated position represented by the difference between the estimated position information and the second new time information is equal to or less than a predetermined third threshold, and the minimum difference is If it is greater than the target positioning accuracy, or if the movement amount of the transition position is greater than the third threshold value, or both, The position search method is characterized in that notification information indicating movement in a direction approaching the estimated position represented by the associated estimated position information is output to the notification unit.
The present invention relates to a position search method by a position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device, wherein the radio wave characteristic acquisition device of the position search device is the radio wave transmission device. Detecting the radio wave characteristic information representing the radio wave characteristic of the radio wave transmitted by the position search device, and detecting the position information indicating the position where the position search device exists when the position acquisition device of the position search device detects the radio wave characteristic information, A time acquisition device of the position search device detects time information indicating a time when the radio wave characteristic information is detected by the radio wave characteristic acquisition device, and the position search device detects the radio wave characteristic with respect to the radio wave characteristic information. The position information detected by the position search device when the information is detected, the time information indicating the time when the radio wave characteristic information is detected, and the radio wave characteristic information. And the estimated position information calculated based on the position information in association with each other, and the estimated position calculation device of the position search device is the search target based on the radio wave characteristic information and the position information. The estimated position information representing the predicted position is calculated, and the position search device is detected by the radio wave characteristic acquisition device in the moving path of the moving body by being mounted on the moving body and moving. Based on the radio wave characteristic information and the position information detected by the position acquisition device when the radio wave characteristic information is detected, the estimated position information is calculated, and the movement path determination device of the position search device includes: The moving direction of the position search device is determined based on the estimated position information, and notification information indicating the moving direction is generated and provided in the moving body. When the notification information is output to the notification unit, the change amount of the measurement position represented by the difference between the position information associated with the newest time information and the position information associated with the second most recent time information, and the newest The amount of change in the measured position is compared with the amount of change in the estimated position represented by the difference between the estimated position information associated with the time information and the estimated position information associated with the second newest time information. If the change amount of the measurement position is not greater than or equal to the change amount of the estimated position, notification information indicating that the current traveling direction is maintained is transferred to the notification unit. Each of the position information detected by the position search device and the latest time information among the estimated information when the change amount of the measurement position is equal to or greater than the change amount of the estimated position. Among the differences between the estimated position information and the estimated position information associated with is determined whether or not the minimum difference is less than or equal to the target positioning accuracy predetermined as a value allowed as a search result of the radio wave transmitter, The amount of movement of the estimated position represented by the difference between the estimated position information associated with the newest time information and the estimated position information associated with the second most recent time information is less than or equal to a predetermined fourth threshold value. If the minimum difference is larger than the target positioning accuracy, or the movement amount of the transition position is larger than the fourth threshold, or both, the newest time is determined. Notification information indicating movement in a direction approaching the estimated position represented by the estimated position information associated with the information is output to the notification unit, and the minimum difference is When the target positioning accuracy is less than or equal to and the movement amount of the transition position is less than or equal to the fourth threshold, a surrounding area of the estimated position represented by the estimated position information associated with the newest time information is determined in advance. It is equally divided by the determined number, and it is determined whether or not the position information is detected in each of the equally divided peripheral areas, and at least one position information is detected in all of the divided peripheral areas. If not, output notification information indicating that the position information is moved in a direction toward the divided surrounding area where the position information is not detected from the estimated position represented by the estimated position information associated with the newest time information. Is a position search method characterized by.

  According to the present invention, it is possible to improve the positioning accuracy of the radio wave transmission device without increasing the number of radio wave characteristic acquisition devices.

It is the schematic shown about an example of the position search system which concerns on 1st Embodiment of this invention. It is a reference diagram for explaining the concept of movement of the position search apparatus according to the present invention. It is the schematic shown about an example of the position search system which concerns on 2nd Embodiment of this invention. It is a flowchart for demonstrating an example of the 1st implementation method utilized with the position search system which concerns on 1st, 2 embodiment of this invention. FIG. 5 is a reference diagram illustrating an example of an implementation place where a position search is performed using the first implementation method illustrated in FIG. 4. FIG. 5 is a reference diagram illustrating an example of a result of a position search using the first implementation method illustrated in FIG. 4. FIG. 5 is a reference diagram for explaining a part of processing included in the first implementation method shown in FIG. 4. It is a flowchart for demonstrating an example of the 2nd implementation method utilized with the position search system which concerns on 1st, 2 embodiment of this invention. It is a flowchart for demonstrating an example of the 3rd implementation method utilized with the position search system which concerns on 1st, 2 embodiment of this invention. FIG. 10 is a reference diagram illustrating an example of an implementation place where a position search is performed using the third implementation method illustrated in FIG. 9. FIG. 10 is a reference diagram illustrating an example of a result of position search using the third implementation method illustrated in FIG. 9. It is a reference figure which shows a prior art example.

[First Embodiment]
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram illustrating an example of a position search system according to the present embodiment.
As shown in FIG. 1, the position search system includes a radio wave transmission device 10 that is a position search target, and a portable position search device 30 that is mounted on the mobile body 20 and can move with the mobile body 20. The position search device 30 predicts the position of the radio wave transmission device 10 using any one of the first to third implementation methods described below, and the radio wave transmission device 10 that is the search target. Estimated position information representing a position predicted as a position is calculated.

  The radio wave transmission device 10 transmits a radio wave having a wavelength that can be received by the position search device 30 and is necessary for performing positioning.

The moving body 20 is, for example, a moving body such as an automobile on which an observer can board and the observer can control the moving direction. Here, a position search device 30 is fixedly installed on the moving body 20, and the position of the position search device 30 and the position of the moving body 20 can be regarded as the same.
In addition, when the position search result is obtained by the position search device 30, the mobile body 20 includes a notification unit 21 that notifies the observer operating the mobile body 20 of the position search result. The notification unit 21 is a display device (for example, a liquid crystal display device) that displays an image according to a position search result, an audio playback device (for example, a speaker device) that reproduces sound according to the position search result, or the like. is there.
Note that an observer who controls the moving body 20 uses the estimated position information (estimated position or existence probability distribution) obtained by the position search device 30 and uses the position search device 30 according to his own empirical rules. A travel route can be determined.

The position search device 30 includes a radio wave characteristic acquisition device 31, a position acquisition device 32, a time acquisition device 33, an estimated position calculation device 34, a storage unit 35, and an operation unit 36.
The radio wave characteristic acquisition device 31 includes an antenna 31A that receives a radio wave transmitted from the radio wave transmission device 10, and based on the radio wave received by the antenna 31A, the electric field strength, radio wave arrival angle, radio wave arrival time, and radio wave arrival time difference of this radio wave. The radio wave characteristic information indicating the radio wave characteristic such as the above is detected and output to the estimated position calculation device 34. Here, the case where the radio wave characteristic acquisition device 31 continuously detects the electric field strengths r _{1 to} r _i in the radio wave characteristic information at predetermined timings will be described.

The position acquisition device 32 detects the position of the position search device 30 using a technique such as GPS (Global Positioning System) and outputs the position to the estimated position calculation device 34. The position acquisition device 32 can detect position information indicating the position of the position search device 30 when the radio wave characteristic acquisition device 31 detects the radio wave characteristic information.
For example, the position acquisition device 32 has a predetermined timing at which the radio wave characteristic acquisition device 31 detects the radio wave characteristic information, detects the position information at this timing, and outputs the position information to the estimated position calculation device 34. Alternatively, the position acquisition device 32 detects the timing at which the radio wave characteristic information is detected by notifying the estimated position calculation device 34 that the radio wave characteristic information has been input to the estimated position calculation device 34, and detects the position information. The structure to detect may be sufficient.
Here, the position acquisition device 32 continuously detects a plurality of measurement coordinates P _{1 to} P _i at a predetermined timing as position information.

The time acquisition device 33 detects time information indicating the time when the radio wave characteristic information is detected by the radio wave characteristic acquisition device 31 and outputs the time information to the estimated position calculation device 34. The time acquisition device 33 always keeps time information indicating time and can output it to the estimated position calculation device 34. Alternatively, when the position acquisition device 32 detects position information at the same timing as the time when the radio wave characteristic acquisition device 31 detects the radio wave characteristic information, the time acquisition device 33 detects the time when the position information is detected by the position acquisition device 32. It is also possible to detect time information representing.
Here, the time acquisition device 33 continuously detects time information T _{1 to} T _i representing the time when the electric field strengths r _{1 to} r _i are detected.

  Based on the radio wave characteristic information input from the radio wave characteristic acquisition device 31, the estimated position calculation device 34 estimates the position that is predicted as the position of the radio wave transmitter 10 that is the search target at the position where the radio wave characteristic information is detected. Calculate location information. More specifically, the estimated position information is information indicating a moving direction of the position search device 30 from the current position toward the radio wave transmission device 10 in order for the position search device 30 to approach the radio wave transmission device 10. In the present embodiment, this estimated position information is referred to by an observer because the position search device 30 moves.

The estimated position information is weighted to the position information detected by the position acquisition device 32 using the radio wave characteristic information detected by the radio wave characteristic acquisition device 31 when the first implementation method described below is used. It is the center of gravity position.
Further, when the second implementation method described below is used, the estimated position information is estimated such that the variance of the value obtained by subtracting the propagation distance attenuation equivalent amount from the radio wave characteristic information detected by the radio wave characteristic acquisition device 31 is minimized. Position.
Furthermore, when the third implementation method described below is used, the estimated position information is calculated using a variance of values obtained by subtracting the propagation distance attenuation equivalent amount from the radio wave characteristic information detected by the radio wave characteristic acquisition device 31. The existence probability distribution representing the probability that the radio wave transmission device 10 exists.

In the storage unit 35, for example, electric field strengths r _{1 to} r _i that are radio wave characteristic information, measurement coordinates P _{1 to} P _i that are position information, and estimated coordinates Q _{1 to} Q _i that are estimated position information are estimated. Stored by the position calculator 34.
Further, the target positioning accuracy C, which is determined in advance as an allowable range as a search result (final estimated position) of the radio wave transmission device 10, is input and stored in the storage unit 35 via the operation unit 36. The target positioning accuracy C is determined by the observer via the operation unit 36 based on the observable geographical environment conditions (for example, the distance between movable alleys if the radio wave transmission device 10 is searched along the road). Determined. Here, for example, the target positioning accuracy C = 100 m.
Further, the storage unit 35 stores a plurality of threshold values and the like. For example, the threshold value γ is a threshold value that is referred to by the estimated position calculation device 34 when compared with the estimated point moving distance | Q _i -Q _i-1 |, and is sufficiently smaller than the target positioning accuracy C. (Generally about 1/10 to 1/100) is predetermined.

  The operation unit 36 receives an operation input from the observer and outputs operation information corresponding to the operation input to the estimated position calculation device 34.

Here, the relationship between the radio wave characteristic information, the position information, and the time information detected by the radio wave characteristic acquisition device 31, the position acquisition device 32, and the time acquisition device 33, and the movement path of the moving body 20 will be described with reference to FIG. This will be specifically described. FIG. 2 is a diagram for explaining the concept of movement of the position search device 30 in the present embodiment.
When the moving body 20 moves as shown in FIG. 2, time information T = T ₁ , T ₂ ,..., T _n indicating the time when the radio wave characteristic acquisition device 31 detects the radio wave characteristic information is set by the time acquisition device 33. is detected, the time information _{T = T 1, T 2,} ···, the position information detected by the position acquisition unit 32 in the _{T n} (measurement _{coordinate) P = P 1, P 2} , ···, is _{P n} can get.

As described above, in the position search system according to the present embodiment, since the position search device 30 moves as the moving body 20 moves, it is possible to detect radio wave characteristic information at an arbitrary place where the moving body 20 can move. .
For example, when the radio wave characteristic acquisition device 31 detects the radio wave characteristic information representing the electric field strength and the position search device 30 performs positioning using the radio wave characteristic information, the direction in which the electric field strength increases immediately after the start of the observation with the low electric field strength. (For example, movement corresponding to the time information T _{1 to} T ₅ ), and in a region where the electric field intensity is large, the electric field intensity observation points are taken densely and moved slowly (for example, to the time information T _{6 to} T ₁₄₎ . Corresponding movement).
Thereby, in the position search system as shown in FIG. 12, it is possible to realize highly accurate positioning with a smaller number of observations or less observation time compared to the case of detecting planar radio wave characteristic information. it can.

Therefore, the estimated position information is calculated every time the observation point of the radio wave characteristic is updated, and the observer searches the radio wave transmission device 10 by moving the moving body 20 while optimizing the moving path based on the estimated position information. Thus, it is possible to shorten the time required to search for the position of the radio wave transmission device 10.
In addition, even when using information such as radio wave arrival angle, radio wave arrival time, radio wave arrival time difference instead of electric field strength as radio wave characteristics, radio wave characteristic observation points that are suitable for acquiring radio wave characteristics are also adaptive. By moving while selecting, high-accuracy positioning can be realized with fewer observation times or less observation time.

On the other hand, in the conventional embodiment as shown in FIG. 12, the location of the radio wave characteristic acquisition device 930 is fixed. Therefore, considering that the radio wave transmission device 10 can be installed at an arbitrary place, it is necessary to install the radio wave characteristic acquisition device 930 uniformly in advance in order to obtain positioning accuracy uniformly.
However, in this embodiment, the position search device 30 is moved, and the estimated position calculation device 34 estimates the position of the radio wave transmission device 10 based on the radio wave characteristic information and the position information continuously detected along with this movement. Thereby, without increasing the number of radio wave characteristic acquisition apparatuses 930, positioning accuracy can be improved, and the effort and cost required for installing a huge number of radio wave characteristic acquisition apparatuses can be reduced.

In the position search device 30, the timing at which the radio wave characteristic acquisition device 31 receives radio waves, the timing at which the position acquisition device 32 detects position information, and the timing at which the time acquisition device 33 detects time information are the same. Preferably, for example, the following three timings can be used by using the following method.
For example, the estimated position calculation device 34 uses the radio wave characteristic information detected by the radio wave characteristic acquisition device 31 as position information detected by the position acquisition device 32 when the radio wave characteristic information is detected. Time information indicating the time when the radio wave characteristic information is detected and estimated position information calculated based on the radio wave characteristic information and the position information are stored in the storage unit 35 in association with each other.

  As a result, even when the single radio wave characteristic acquisition device 31 is moved, radio wave characteristic information can be repeatedly detected at different locations, and positioning accuracy equivalent to that obtained when the radio wave characteristic acquisition devices are increased can be obtained. be able to.

Note that the position search device 30 generates image data representing a transition between the movement path of the position search device 30 and the estimated position information based on the estimated position information calculated by the estimated position calculation device 34, and outputs the image data to the notification unit 21. be able to.
The image data generated by the estimated position calculation device 34 is an image as shown in FIGS. The observer is preferably a person who has knowledge for estimating the position of the radio wave transmission device 10 based on this image, and can move the moving body 20 in the direction in which the radio wave transmission device 10 is estimated. .
Thus, the observer refers to the image displayed on the notification unit 21 and observes the radio wave characteristic while adaptively selecting a movement route suitable for position search as the movement route of the moving body 20. Therefore, highly accurate positioning can be realized with fewer observation times or less observation time.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described with reference to FIG. FIG. 3 is a schematic diagram illustrating an example of a position search system according to the second embodiment.
As shown in FIG. 3, the position search system according to the present embodiment is different from the first embodiment in that the position search device 130 includes a movement route determination device 37. Since other configurations are the same as those in the first embodiment, detailed description will be omitted by assigning the same reference numerals.

The moving path determination device 37 determines the moving direction of the moving body 20 based on the estimated position information calculated by the estimated position calculating device 34, generates notification information indicating the moving direction, and notifies the moving unit 20 of the notification unit. To 21. The movement path determination device 37 can determine the moving direction of the moving body 20 based on the estimated position information and the like according to first to third implementation methods to be described later in detail.
With this configuration, as described in the first embodiment, even if the observer cannot determine the moving direction of the position search device 30 with reference to the image generated based on the estimated position information by the estimated position calculation device 34, By moving the moving body 20 according to the moving direction obtained based on the estimated position information, highly accurate positioning can be realized with a smaller number of observations or a shorter observation time.

  Hereinafter, an example of an implementation method in which the position search system according to the first and second embodiments can be used will be described. For convenience of explanation, an implementation method in the position search system according to the second embodiment will be described.

[First Implementation Method]
First, the first implementation method will be described in detail.
For example, when the electric field strength is detected as the radio wave characteristic information by the radio wave characteristic acquisition device 31, the estimated position calculation device 34 calculates the barycentric coordinates on the two-dimensional coordinate plane weighted to the observation point coordinates using the electric field strength. Use.
That is, the estimated position calculation device 34 uses the i-th measurement coordinates detected as the position information by the position acquisition device 32 as P _i , and the i-th field strength as the radio characteristic information detected by the radio wave characteristic acquisition device 31 as r _i. Then, using the electric field strengths r _{1 to} r _i and the measurement coordinates P _{1 to} P _i , the estimated position coordinates Q _i obtained by the i-th detection are calculated using the following formula (formula (1)).
Here, the electric field strengths r _{1 to} r _i are radio wave characteristic information, the measurement coordinates P _{1 to} P _i are position information, and the estimated coordinates Q _i are estimated position information.

In this way, the estimated position calculation device 34 calculates and updates the estimated coordinates Q _i of the radio wave transmission device 10 each time the radio wave characteristic information is detected. Further, the time acquisition device 33 detects the time information T _{1 to} T _i and outputs it to the estimated position calculation device 34.

Note that it is not necessary to strictly determine the update interval of the observation point (measurement coordinate P _i ) and the estimation point (estimation coordinate Q _i ). For example, updating may be performed based on an arbitrary moving distance, or when the position search device 130 is moved on a vehicle that continues to move at a certain speed, such as the moving body 20, based on an arbitrary time interval. It may be updated. Alternatively, the update interval may be determined according to the surrounding geographical environmental conditions such as a road intersection.

  Next, referring to FIG. 4, an example of a method in which the position search device 130 searches for the position of the radio wave transmission device 10 and the movement route determination device 37 determines the movement direction using the first implementation method. explain. FIG. 4 is a flowchart for explaining an example of the first implementation method.

As shown in FIG. 4, when the target positioning accuracy C is selected by the observer via the operation unit 36, the value of the target positioning system C is stored in the storage unit 35 (step ST100). Then, the electric field characteristic acquisition device 31 detects the electric field strength r ₁ , and the measurement coordinate P _{1 at} this time is detected by the position acquisition device 32. Further, the time information T ₁ at this time is detected by the time acquisition device 33. When the electric field strength r ₁ , the measurement coordinate P ₁ and the time information T ₁ are input, the estimated position calculation device 34 calculates the estimated coordinate Q ₁ based on the electric field strength r ₁ and the measurement coordinate P ₁ and is input. The electric field strength r ₁ , the measurement coordinate P _{1, the} time information T _1, and the calculated estimated coordinate Q ₁ are stored in the storage unit 35 in association with each other.

Then, the moving body 20 is moved in any direction (step ST110), the locator 130 is also moved with the movement, along with the electric field strength r ₂ is detected by the wave characteristic acquisition unit 31, measurement coordinates at this time P ₂ is detected by the position acquisition device 32. Further, the time information T ₂ of the time this is detected by the time acquisition unit 33. When the electric field strength r ₂ , the measurement coordinate P ₂ and the time information T ₂ are input to the estimated position calculation device 34, the estimated position calculation device 34 stores the electric field strength r _{2, the} measurement coordinate P ₂ and the storage unit 36. Based on the stored electric field strength r ₁ and the measurement coordinate P ₁ , the estimated coordinate Q ₂ that is the estimated position information is calculated according to the equation (1). Then, the estimated position calculation device 34 stores the input electric field strength r ₂ , measurement coordinate P ₂ and time information T ₂ and the calculated estimated coordinate Q _{2 in} the storage unit 35 in association with each other (step ST120). ).

Then, the mobile routing device 37, the change amount of the measurement coordinates _{P i | P i -P i-} 1 | and the amount of change in the estimated coordinates _{Q i | Q i -Q i-} 1 | and comparing (step ST130) . When the amount of change | Q ₂ −Q ₁ | of the estimated coordinate Q _i is large (step ST 130 —NO), the movement route determination device 37 displays notification information indicating that the current traveling direction is maintained and further moves. It outputs to the notification part 21 as a search result (step ST140). Thereby, the notification part 21 notifies that it moves further, maintaining the present advancing direction.

Then, the process returns to step ST120, with the electric field strength r ₃ is detected by the wave characteristic acquisition unit 31, the measurement coordinates P ₃ at this time is detected by the position acquisition unit 32. Further, the time information T ₃ at this time is detected by the time acquisition device 33. When the electric field strength r ₃ , the measurement coordinate P ₃ and the time information T ₃ are input, the estimated position calculation device 34, based on the electric field strengths r _{1 to} r ₃ 3 and the measurement coordinates P _{1 to} P ₃ , ₃ and the input electric field strength r ₃ , measurement coordinate P _3, time information T ₃ , and estimated coordinate Q ₃ are associated with each other and stored in the storage unit 35 (step ST120).

On the other hand, in step ST130, the estimated amount of change in coordinate _{Q i | Q} 2 -Q _{1 |} is measured coordinate change amount of _{P i | P i -P i-} 1 | is equal to or less than (steps ST130-YES), mobile The route determination device 37 determines whether or not the minimum distance among all the observation points P _{1 to} P _i stored in the storage unit 35 and the latest estimated coordinates Q _i is equal to or less than the target positioning accuracy C. And whether or not the moving distance | Q _i −Q _i−1 | of the latest estimated point is equal to or smaller than the threshold γ (step ST150).
For example, when the measurement coordinates P _{1 to} P ₃ are stored in the storage unit 35, the movement path determination device 37 determines the difference between the measurement coordinates P ₁ and the estimated coordinates Q ₃ , the measurement coordinates P ₂ and the estimated coordinates Q _3. And the difference between the measurement coordinate P ₃ and the estimated coordinate Q ₃ is determined whether or not the minimum difference (hereinafter referred to as the minimum difference) is equal to or less than the target positioning accuracy C. It is determined whether or not the estimated point moving distance | Q ₃ −Q ₂ | is equal to or less than a threshold value γ.

Here, among the differences between the measured coordinates P _{1 to} P ₃ and the estimated coordinates Q ₃ , the minimum difference is larger than the target positioning accuracy C, or the latest estimated point moving distance | Q ₃ -Q ₂ | If it is larger than γ or both (step ST150-NO), the movement path determination device 37 notifies that it further moves by changing the direction in the direction approaching the estimated coordinates Q _i or in a random direction. Information is output to the notification unit 21 as a position search result (step ST160). As a result, the notification unit 21 notifies the observer of a notification indicating that the direction changes to a direction approaching the estimated coordinate Q _i or a random direction and further moves.

Then, the process returns to step ST120, with the electric field strength r ₄ is detected by the wave characteristic acquisition unit 31, measurement coordinates P ₄ at this time is detected by the position acquisition unit 32. Further, the time information T ₄ at this time is detected by the time acquisition device 33. When the electric field strength r ₄ , the measurement coordinate P ₄ and the time information T ₄ are input, the estimated position calculation device 34 is based on the electric field strengths r _{1 to} r ₄ and the measurement coordinates P _{1 to} P ₄ , and the estimated coordinate Q _4. And the input electric field strength r ₄ , measurement coordinate P ₄ and time information T ₄ , and estimated coordinate Q ₄ are associated with each other and stored in the storage unit 35 (step ST120).

On the other hand, in step ST150, of the difference between the measurement coordinates _P 1 to P ₃ and the estimated coordinates _{Q 3,} and the minimum difference is less than the target positioning accuracy C, and the moving distance of the most recent estimate point _| Q 3 -Q ₂ | is equal to or smaller than the threshold value gamma (step ST150-YES), the mobile routing device 37, the area around the estimated coordinates Q ₃ equally divided into N divided area around the equal split 360 / N degrees In each of the above, at least one determines whether or not an observation point history (measurement coordinates P _i ) exists (step ST170).

Here, when a divided peripheral area where at least one observation point history does not exist is detected from the equally divided 360 / N degree peripheral areas (step ST170-NO), the observation is performed from the estimated coordinates Q _i. Notification information indicating that the direction is changed and moved to the divided peripheral region where no point history exists is output to the notification unit 21 as a position search result (step ST180). As a result, the notification unit 21 notifies the observer of a notification indicating that the direction change to the divided peripheral area where the observation point history does not exist when viewed from the estimated coordinates Q _i is moved.

Then, the process returns to step ST120, with the electric field strength r ₅ is detected by the wave characteristic acquisition unit 31, the measurement coordinates P ₅ at this time is detected by the position acquisition unit 32. Further, the time information T ₅ at this time is detected by the time acquisition unit 33. When the electric field strength r ₅ , the measurement coordinate P ₅ and the time information T ₅ are input, the estimated position calculation device 34 is based on the electric field strengths r _{1 to} r ₅ and the measurement coordinates P _{1 to} P ₅ , and the estimated coordinate Q _5. And the input electric field strength r ₅ , measurement coordinate P _5, time information T ₅ , and estimated coordinate Q ₅ are associated with each other and stored in the storage unit 35 (step ST120).
Note that N is a predetermined parameter. However, when a road or the like is assumed as the moving route of the mobile body 20, branching is often performed in four directions, and thus N = 4 is preferable.

On the other hand, in step ST170, when at least one observation point history exists in any divided frequency region among the 360 / N degree divided peripheral regions that are equally divided (step ST170-YES), the movement route determination device 37 terminates the position search with the latest estimated coordinates Q _i in the estimated position information stored in the storage unit 35 as the final estimated position (step ST190). At this time, the movement route determination device 37 outputs notification information indicating the end of movement to the notification unit 21.

The power propagation attenuation in the radio propagation path of the radio wave transmitted from the radio wave transmission device 10 is inversely proportional to the β power of the distance between the radio wave transmission device 10 and the position search device 130 (where β is a propagation attenuation constant). This relationship is generally known. Here, the propagation attenuation constant β is a constant determined by the propagation path environment, and the propagation attenuation constant β in a general indoor / outdoor wireless propagation environment is 3 to 4 (2 in free space).
Therefore, based on Expression (1), the mobile object 20 equipped with the position search device 130 moves in the vicinity of the radio wave transmission device 10, so that the electric field strength of the radio wave transmitted from the radio wave transmission device 10 is determined. Is obtained, the estimated position calculation unit 34 can weight the estimated coordinates Q _i fairly steeply.
Therefore, the position search device 130 can detect the final estimated position so as to surround the estimated coordinates Q _i while passing in the vicinity of the radio wave transmitting device 10. For this reason, if the position search ends when the observer has confirmed that this final estimated position becomes a saddle point of the electric field strength, the positioning accuracy can be improved by increasing the number of observation points near the estimated point.

Further, as described above, the observer can select an optimal movement route by notifying the observer of an appropriate movement route via the notification unit 21. Thereby, compared with the case where it moves at random according to an observer's intuition, the frequency | count of observation of electric field strength and observation time can be shortened.
Note that, as described above, in the first implementation method using the barycentric coordinates weighted by the electric field strength, unlike the second implementation method described later, it is necessary to know in advance the propagation attenuation constant determined by the location where the position search is performed. In addition, the position search can be realized easily.

Next, with reference to FIGS. 5 to 7, the relationship between the moving path of the moving body 20 and the transition path of the estimated coordinates Q _i obtained by the position search device 130 when the first implementation method is actually applied. An example will be described.
FIG. 5 is a schematic diagram illustrating an implementation place where the position search system according to the present embodiment is implemented.
As shown in FIG. 5, this implementation location is, for example, an urban area where single-family houses, small and medium-sized public facilities, commercial facilities, etc. are densely populated, and the moving body 20 moves on the road running through this implementation location. .
The radio wave transmission device 10 is mounted on, for example, an automobile parked at a star mark position shown in FIG. 5, and a transmission antenna (not shown) is attached to the roof of the automobile. Via this transmission antenna, the radio wave transmitter 10 continuously transmits radio waves in the 280 MHz band as radio waves necessary for performing positioning.

As shown in FIG. 5, the position search device 130 moves together with the moving body 20 when the observer drives the moving body 20 according to the traffic rules from the measurement start time toward the radio wave transmission device 10.
The moving body 20 equipped with the position search device 130 starts moving from an observation start point about 600 m away from the radio wave transmission device 10 in the north-northwest direction, and moves under the control of the observer. The position search device 130 mounted on the moving body 20 acquires the electric field strength while changing the observation point.
The measurement coordinates P _i representing the position of the position search device 130 are square pointers, the estimated coordinates Q _i obtained by the estimated position calculation device 34 are round pointers, and the movement path of the position search device 130 is a dotted line. The transition path of the coordinate Q _i is indicated by a solid line.

  This position search device 130 updates observation points (detection of radio wave characteristic information and position information) at intervals of about 30 seconds except when the vehicle is stopped. This is equivalent to acquiring radio wave characteristics at intervals of about 120 m, assuming that the vehicle moves at a speed of about 15 km / h.

Next, with reference to FIGS. 6 and 7, an implementation result when the first implementation method is used will be described.
6, estimates the measurement coordinates _P 1 _{to P 22} in the moving path of the locator 130 from the measurement coordinates _{P 1} at the measurement start position to the position coordinate _{P 22} in the estimation end position, from the estimated coordinates _{Q 1} at the measurement starting position The estimated coordinates Q ₁ -Q ₂₂ in the transition path to the estimated coordinates Q ₂₂ at the end position are shown.
As shown in FIG. 6, the transition path of the estimated coordinate Q _i passes through the inside of the movement path of the measurement coordinate P ₁ . Note that the estimated position calculation device 34 according to the first embodiment generates an image as shown in FIG. 6 as image data to be displayed on the notification unit 21.

FIG. 7 is a reference diagram for explaining the process of step ST170 shown in FIG. FIG. 7 shows the target positioning accuracy and the state of division of the surrounding area of the final estimated point Q _i (when N = 4).
As described above, the movement route determination device 37 has at least one observation point in the divided peripheral region obtained by dividing the peripheral region whose radius is the target estimation accuracy C (for example, 100 m) centering on the estimated coordinates Q _i into N = 4. It is detected whether or not there is a history (measurement coordinates P _i ), and it is determined whether or not there is a divided peripheral region in which at least one observation point history does not exist among all the divided peripheral regions.
In this way, the moving body 20 is moved along the moving direction determined by the position search device 130 using the first implementation method, so that the positioning accuracy with a positioning estimation error of about 50 m with respect to the target estimation accuracy 100 m. Was able to be realized.

[Second Implementation Method]
Next, a second implementation method different from the first implementation method described above will be described.
Compared to the first implementation method, this second implementation method uses a two-dimensional mesh to divide the range to be searched in order to carry out positioning with higher accuracy and in a shorter time. This is a method of updating the observation point P _i and the estimation point Q _i based on the maximum likelihood estimation method in which propagation attenuation is calculated according to the propagation attenuation rule and the most likely estimation point candidate is used as the estimation point. .

と表すことができる。 The electric field strength r _i [dBm] observed in the position search device 130 is obtained by using the transmission power T _s [dBm] of the radio wave transmission device 10 and the attenuation L _i [dB] of the propagation path to the i-th observation point.

It can be expressed as.

Here, it is assumed that the coordinates Q _i = (x, y) of the radio wave transmission device 10 are estimated by the maximum likelihood determination using the distance attenuation characteristics of the radio signal and the observation results from the 1st to i-th observations. Think.

である。 The estimated coordinates (x, y) are

It is.

However, p (x, y | r ₁ , r ₂ ,..., R _i ) is a coupling probability density function in which the coordinates of the radio wave transmitter 10 are (x, y) after the i-th field intensity observation. is there.

と変形できる。 However, since it is generally difficult to calculate the conditional probability p (x, y | r ₁ , r ₂ ,..., R _i ), the probability distribution of the coordinates (x, y) of the radio wave transmitter is uniform. Assuming that

And can be transformed.

That is, it can be replaced with a problem of estimating the position (x, y) that maximizes the conditional probability p (r ₁ , r ₂ ,..., R _i | x, y) that can be easily calculated.

と展開することができる。 Here, if the observed electric field strengths r _k (k = 1, 2,..., I) are uncorrelated with each other, the conditional probability p (r ₁ , r ₂ ,..., R _i | x, y) is

And can be expanded.

Furthermore, Okumura - as represented by Hata equation, the power loss L _i in a radio wave propagation can be regarded as being determined by the variation of distance attenuation and lognormal distribution is inversely proportional to the squared β distance.

が成り立つ。 Therefore,

Holds.

Where α and β are constants determined by the location search location, d is the distance between the transmission device (here, the radio wave transmission device 10) and the reception device (here, the location search device 130), and N (0, σ ² ) is an average. This is a logarithmic normal distribution of 0 and variance σ ² (standard deviation σ).

Incidentally, alpha, beta can be determined by, for example, it estimated using the reception level r _k of the field strength acquired in advance for determining or position estimate by measuring the distance characteristic of the propagation attenuation.

と表せる。 At this time, the conditional probability p (r _i | x, y) is

It can be expressed.

Here, (X _i , Y _i ) is the i-th measurement coordinate P ₁ detected by the position acquisition device 32.

を用いて表現できる。 Further, from the equations (5) and (7), the conditional probability p (r ₁ , r ₂ ,..., R _i | x, y) is

Can be expressed using.

のように推定できる。 Furthermore, using the fact that exp (·) is a monotonically increasing function, estimated coordinates (x _est , y _est ) representing the estimated position of the radio wave transmission device 10 are

It can be estimated as follows.

  This corresponds to estimating the maximum likelihood as the position of the radio wave transmission device 10 at the position where the variance of the value obtained by subtracting the propagation distance attenuation equivalent amount from the observed electric field strength is minimized.

Therefore, as in the first implementation method, the position search device 130 updates (calculates and stores the estimated coordinates Q _i of the radio wave transmission device 10 using the estimated position calculation device 34 each time a new observation is made. Stored in the unit 35).

  Next, referring to FIG. 8, an example of a method in which the position search device 130 searches for the position of the radio wave transmission device 10 and the movement route determination device 37 determines the movement direction using the second implementation method. explain. FIG. 8 is a flowchart for explaining an example of the second implementation method.

As shown in FIG. 8, when the target positioning accuracy C is selected by the observer via the operation unit 36, the value of the target positioning system C is stored in the storage unit 35 (step ST300). Then, the electric field characteristic acquisition device 31 detects the electric field strength r ₁ , and the measurement coordinate P _{1 at} this time is detected by the position acquisition device 32. Further, the time information T ₁ at this time is detected by the time acquisition device 33. Then, the estimated position calculation device 34 calculates the estimated coordinates Q ₁ (x _est , y _est ) according to the equation (9) based on the electric field strength r ₁ and the measured coordinates P ₁ , and the input electric field strength r ₁ , measured coordinates P ₁ and time information T ₁ and the calculated estimated coordinates Q ₁ (x _est , y _est ) are stored in the storage unit 35 in association with each other.

Then, the moving body 20 is moved in any direction (step ST 310), the locator 130 is also moved with the movement, along with the electric field strength r ₂ is detected by the wave characteristic acquisition unit 31, measurement coordinates at this time P ₂ is detected by the position acquisition device 32. Further, the time information T ₂ of the time this is detected by the time acquisition unit 33. When the electric field strength r ₂ , the measurement coordinate P ₂ and the time information T ₂ are input to the estimated position calculation device 34, the electric field strength r ₂ and the measurement coordinate P ₂ and the electric field strength r stored in the storage unit 36. ₁ and the measured coordinates P ₁ , the estimated position calculation device 34 calculates estimated coordinates Q ₂ (x _est , y _est ) as estimated position information according to the equation (9). Then, the estimated position calculation device 34 stores the input electric field strength r ₂ , measurement coordinates P ₂ and time information T _{2 in association} with the calculated estimated coordinates Q ₂ (x _est , y _est ), respectively. 35 (step ST320).

Then, the movement route determination device 37 determines whether or not all the distances between all the observation points P _{1 to} P _i stored in the storage unit 35 and the latest estimated coordinates Q _i are equal to or less than the target positioning accuracy C. And whether or not the moving distance | Q _i −Q _i−1 | of the latest estimated point is equal to or smaller than the threshold value γ (step ST330).
For example, when the measurement coordinates P _{1 to} P ₂ are stored in the storage unit 35, the movement path determination device 37 determines the difference between the measurement coordinates P ₁ and the estimated coordinates Q ₂ (x _est , y _est ), and Among the differences between the measurement coordinates P ₂ and the estimated coordinates Q ₂ (x _est , y _est ), it is determined whether or not the minimum difference is equal to or less than the target positioning accuracy C, and the moving distance of the latest estimated point | Q ₂ It is determined whether −Q ₁ | is equal to or less than a threshold value γ.

Here, among the differences between the measurement coordinates P _{1 to} P ₂ and the estimated coordinates Q ₂ (x _est , y _est ), the minimum difference is larger than the target positioning accuracy C or the latest estimated point moving distance | Q _{When 2-} Q ₁ | is larger than the threshold value γ or both (step ST330-NO), the movement path determination device 37 moves in the direction approaching the estimated coordinates Q _i (x _est , y _est ). Notification information indicating that the vehicle has been changed and moved is output to the notification unit 21 as a position search result (step ST340). Thereby, the notification unit 21 notifies the observer of a notification indicating that the direction is changed in the direction approaching the estimated coordinates Q _i (x _est , y _est ) and further moved.

Then, the process returns to step ST 320, along with the electric field strength r ₃ is detected by the wave characteristic acquisition unit 31, the measurement coordinates P ₃ at this time is detected by the position acquisition unit 32. Further, the time information T ₃ at this time is detected by the time acquisition device 33. When the electric field strength r ₃ , the measurement coordinate P ₃ and the time information T ₃ are input, the estimated position calculation device 34 based on the electric field strengths r _{1 to} r ₃ and the measurement coordinates P _{1 to} P ₃ , the estimated coordinate Q _3. (X _est , y _est ) is calculated, and the input electric field strength r ₃ , measurement coordinates P ₃ and time information T ₃ , and estimated coordinates Q ₃ (x _est , y _est ) are associated with each other and stored. 35 (step ST320).

On the other hand, in step ST330, among the differences between the measurement coordinates P _{1 to} P _i and the estimated coordinates Q _i (x _est , y _est ), the minimum difference is the target positioning accuracy C or less and the latest estimated point is moved. If the distance | Q _i −Q _i−1 | is equal to or smaller than the threshold γ (step ST330—YES), the movement path determination device 37 sets the latest estimated coordinates Q _i among the estimated position information stored in the storage unit 35. The position search is terminated using (x _est , y _est ) as the final estimated position (step ST350). At this time, the movement route determination device 37 outputs notification information indicating the end of movement to the notification unit 21.

As described above, the second implementation method does not include a procedure corresponding to steps ST130, 140, 170, and 180 shown in FIG. 4 as compared with the first implementation method. The reason will be briefly described below.
In the first implementation method described above, since the estimated coordinates Q _i are presented as the center of gravity of the observation point coordinates, the estimated position is presented only inside the observation point group (movement path).
On the other hand, in the second implementation method, the observed electric field strength information is converted into a propagation distance attenuation equivalent amount and geometrically reflected on a two-dimensional plane to perform position estimation. Therefore, even if the radio wave transmission device 10 exists outside the observation point group (the movement path of the position search device 130) before the position search device 130 approaches the vicinity of the radio wave transmission device 10. The distance from the observation point group and the positional relationship can be reflected in the estimated position. Therefore, the movement route determination device 37 may select a route approaching in the direction of the estimated coordinates Q _i (x _est , y _est ) sequentially updated by the estimated position calculation device 34, and the steps ST130 and 140 are performed. The corresponding first-half route selection procedure can be simplified.

Further, in the first implementation method, the observation is performed so as to surround the four sides of the estimated coordinate Q _i and the final estimated coordinate Q _i is confirmed to be a saddle point of the electric field strength. The estimated coordinate Q _i is determined as the final estimated position.
On the other hand, in the second implementation method, the estimated position calculation device 34 sequentially calculates the result of the likelihood comparison between the estimated candidate points in a certain range area around the estimated coordinates Q _i (x _est , y _est ). The movement route determination device 37 notifies the movement direction. That is, the closer the measured coordinate P _i is to the estimated coordinate Q _i , the more rapidly the likelihood of surrounding candidate points is reduced. Therefore, the estimated coordinates at the time when the measured coordinates P _i and the estimated coordinates Q _i are close to each other and the movement amount of the estimated coordinates Q _i is small can be set as the final estimated position. Therefore, the second half route selection procedure corresponding to steps ST170 and 180 can be simplified.

In both the first implementation method and the second implementation method, one estimated coordinate Q _i is calculated for one measurement coordinate P _i , and the movement path determination device is based on the estimated coordinate Q _i. Reference numeral 37 denotes a movement route.
On the other hand, the dispersion of the value obtained by subtracting the propagation distance attenuation amount corresponding from the electric field intensity shown in Formula (9), for one measurement coordinates P _i, it is possible to calculate a plurality of estimated point candidates. Therefore, the estimated position calculation device 34 can generate a presence probability distribution by calculating a plurality of estimated point candidates as the maximum likelihood estimation result. Further, the movement route determination device 37 can determine the movement route of the position search device 130 based on this existence probability distribution. A third implementation method for searching for the position of the radio wave transmission device 10 using the existence probability distribution of the radio wave transmission device 10 will be described below.

[Third Implementation Method]
Next, a third implementation method different from the first and second implementation methods described above will be described.
Like the second implementation method, the third implementation method divides the range to be searched by a two-dimensional mesh, and each of a plurality of estimation candidate points calculated based on the electric field strength r _i and the measurement coordinates P _i. On the other hand, the propagation attenuation according to the propagation attenuation law is calculated, and the observation points P _i and the existence probability distribution are updated based on the maximum likelihood estimation method in which the most likely estimation point candidate is the estimation point. Is the method.
Since the above-described second implementation method is an algorithm based only on the maximum likelihood result, if there are a plurality of likely positions, the estimation result is not easily narrowed down.
On the other hand, the third implementation method can generate a distribution of existence probabilities representing the likelihood of the estimated position of the radio wave transmission device 10 and reflect it in the route selection, thereby enabling more efficient route selection.

とすると、推定座標Ｑ_ｉ(x,y)に対して計算される分散は

となる。 From equation (9), the value obtained by compensating the propagation distance attenuation equivalent to the electric field strength r _i observed at the observation point represented by each measurement coordinate P _i is

Then, the variance calculated for the estimated coordinates Q _i (x, y) is

It becomes.

The estimated position calculation device 34 uses the expression (11) itself or the expression (11) to generate, as an existence probability distribution, the result of mapping on the two-dimensional plane according to the evaluation function shown in the expression (12), for example. That is, the estimated position calculation device 34 is a variance of values obtained by subtracting the propagation distance attenuation equivalent amount from the radio wave characteristic information (for example, the electric field strengths r _{1 to} r _i ) detected by the radio wave characteristic acquisition device 31 (see Expression (11)). ) Is used to generate an existence probability distribution representing the probability that the radio wave transmission device 10 exists as estimated position information.
The movement route determination device 37 can determine the movement route of the position search device 130 based on this existence probability distribution.

Note that the dispersion of the equation (11) is the propagation attenuation dispersion shown in the equation (6) when the estimated position is correct, that is, when the estimated position represented by a region having a high existence probability in the existence probability distribution is appropriate. σ ² itself.
In addition, the standard deviation σ of propagation attenuation (which is called short-term fluctuation in radio wave propagation) generally takes a value of about 3 to 7 [dB]. Therefore, the estimated position calculation device 34 may determine a threshold value δ described later with reference to FIG. 9 based on these values. This threshold value δ is a threshold value to be compared with the evaluation function, and it is highly possible that the radio wave transmission device 10 exists when the estimated position calculation device 34 detects a region where the evaluation function is smaller than the threshold value δ. This is a predetermined value for detecting a region.
Similarly, the threshold value ε described later with reference to FIG. 9 is a threshold value to be compared with a region where the evaluation function is smaller than the threshold value δ, and can be determined in advance based on the positioning accuracy or the like to be finally obtained.

を、電波発信装置１０の存在確率を評価する評価関数として定義した。
ただし、最尤推定地点(x_est,y_est)は、

で与えられる。 In the third implementation method, the propagation attenuation constant β is assumed to be 3.5, and the standard deviation difference with respect to the maximum likelihood estimation point (x _est , y _est ) in the estimation area, that is,

Is defined as an evaluation function for evaluating the existence probability of the radio wave transmission device 10.
However, the maximum likelihood estimation point (x _est , y _est ) is

Given in.

  The threshold δ is set to about 2 [dB] in consideration of the variation of the evaluation function, and the threshold ε is set to about 100 m square.

Here, it is generally difficult to use μ shown in Expression (11), that is, the dispersion of the electric field strength itself as an evaluation function because the true dispersion of the electric field strength depending on the propagation environment needs to be known in advance.
On the other hand, by defining the evaluation function with η shown in Expression (12), which is the difference between the maximum likelihood estimation point and other points, the portion corresponding to the standard deviation σ of the propagation attenuation depending on the propagation environment is canceled. It is possible to directly reflect only the portion caused by the estimated point error in the evaluation function. Thereby, position estimation accuracy can be improved.

  Next, referring to FIG. 9, an example of a method in which the position search device 130 searches for the position of the radio wave transmission device 10 and the movement route determination device 37 determines the movement direction using the third implementation method. explain. FIG. 9 is a flowchart for explaining an example of the third implementation method.

As shown in FIG. 9, when the target positioning accuracy C is selected by the observer via the operation unit 36, the value of the target positioning system C is stored in the storage unit 35 (step ST500). Then, the electric field characteristic acquisition device 31 detects the electric field strength r ₁ , and the measurement coordinate P _{1 at} this time is detected by the position acquisition device 32. Further, the time information T ₁ at this time is detected by the time acquisition device 33. Then, the estimated position calculation device 34 stores the electric field strength r ₁ , the measurement coordinates P ₁ , and the time information T ₁ in the storage unit 35 in association with each other.

Then, the moving body 20 is moved in any direction (step ST 510), the locator 130 is also moved with the movement, along with the electric field strength r ₂ is detected by the wave characteristic acquisition unit 31, measurement coordinates at this time P ₂ is detected by the position acquisition device 32. Further, the time information T ₂ of the time this is detected by the time acquisition unit 33. When the electric field strength r ₂ , the measurement coordinate P ₂ and the time information T ₂ are input to the estimated position calculation device 34, the electric field strength r ₂ and the measurement coordinate P ₂ and the electric field strength r stored in the storage unit 36. ₁ and the measurement coordinate P ₁ , the estimated position calculation device 34 calculates a value in which the propagation distance attenuation equivalent amount is compensated for the electric field strengths r _{1 to} r ₂ as shown in Expression (10), and is used. The variance as shown in the equation (11) is calculated. Then, the estimated position calculation device 34 generates an existence probability distribution according to the evaluation function shown in the expression (12) using the variance shown in the expression (11), and uses this existence probability distribution as the estimated position information as a movement route. The data is output to the determination device 37.

In this way, the estimated position calculation device 34 generates an existence probability distribution that indicates the degree of existence probability of the radio wave transmission device 10 stepwise based on the electric field strength r _i and the measurement coordinates P _i . Further, the movement route determination device 37 superimposes the existence probability distribution generated by the estimated position calculation device 34 on the map showing the movement route of the position search device 130, and displays image data showing the existence probability distribution on the map. Generate and output to the notification unit 21.
Then, the estimated position calculation device 34 stores the input electric field strength r ₂ , measurement coordinate P ₂ and time information T ₂ and the calculated existence probability distribution in the storage unit 35 in association with each other (step ST520). .

  Next, the movement path determination device 37 detects the area of the region where the evaluation function shown in the equation (12) is smaller than a certain threshold value δ from the existence probability distribution calculated by the estimated position calculation device 34, and this detected It is determined whether or not the area is smaller than a threshold value ε, or whether or not the detected area is a minimum value that does not become smaller than the present time (step ST530). The region where the evaluation function is smaller than a certain threshold δ is a region including a position that is likely to be a position where the radio wave transmission device 10 is located, and is a range where the existence probability is high. Therefore, the movement path determination device 37 determines whether the area of the region where the evaluation function is smaller than a certain threshold δ is smaller than the threshold ε (measurement accuracy), thereby determining the existence probability of the radio wave transmission device 10. It is possible to search for the radio wave transmission device 10 within a range of measurement accuracy by narrowing down a high-frequency region.

  Here, when the area of the region where the evaluation function is smaller than a certain threshold value δ is equal to or larger than the threshold value ε (step ST530-NO), the movement path determination device 37 changes the direction in the direction where the evaluation function is smaller and further moves. Notification information indicating that the information is to be output is output to the notification unit 21 as a position search result (step ST540). Thereby, the notification unit 21 notifies the observer of a notification indicating that the evaluation function changes direction and moves further.

Then, the process returns to step ST 520, along with the electric field strength r ₃ is detected by the wave characteristic acquisition unit 31, the measurement coordinates P ₃ at this time is detected by the position acquisition unit 32. Further, the time information T ₃ at this time is detected by the time acquisition device 33. When the electric field strength r ₃ , the measurement coordinate P _3, and the time information T ₃ are input, the estimated position calculation device 34 calculates an existence probability distribution based on the electric field strengths r _{1 to} r ₃ and the measurement coordinates P _{1 to} P _3. The calculated and input electric field strength r ₃ , measurement coordinate P _3, time information T ₃ , and existence probability distribution are associated with each other and stored in the storage unit 35 (step ST520).

  On the other hand, in step ST530, if the area of the region where the evaluation function is smaller than the threshold δ is smaller than the threshold ε, or if it is not smaller than the current time, or both (step ST530-YES), the movement route The determination device 37 calculates the evaluation function represented by the expression (12) in the region where the evaluation function in the existence probability distribution in which the evaluation function is the minimum becomes smaller than the threshold δ among the existence probability distributions stored in the storage unit 35. One point to be minimized is determined as the final estimated position, and the position search is terminated (step ST550). At this time, the movement route determination device 37 outputs notification information indicating the end of movement to the notification unit 21.

Then, the position search device 130 moves the observation point, and sequentially updates the existence probability distribution of the radio wave transmission device 10 calculated from the dispersion of the observation point P _i and the electric field strength r _i according to the equations (10) to (13). (Generate and store in the storage unit 35).

Next, with reference to FIGS. 10 and 11, the implementation location and search results of the location search system using the third implementation method will be described in more detail.
FIG. 10 is a schematic diagram for explaining an implementation place where the third implementation method is implemented.
As shown in FIG. 10, this place of implementation is, for example, an urban area where single-family houses, small and medium-sized public facilities, commercial facilities, etc. are densely populated, and the moving body 20 moves on the road running through this place of implementation. .
The radio wave transmission device 10 is mounted on, for example, an automobile parked at the position of the star shown in FIG. 10, and a transmission antenna (not shown) is attached to the roof of the automobile. Via this transmission antenna, the radio wave transmitter 10 continuously transmits radio waves in the 280 MHz band as radio waves necessary for performing positioning.

  On the other hand, the moving body 20 equipped with the position search device 130 starts to move from an observation start point at a point about 700 m away from the radio wave transmission device 10 in the east-northeast direction, and moves under the control of the observer. The position search device 130 mounted on the moving body 20 detects the electric field strength while changing the observation point, and the observation point is updated at a movement distance of 20 m. Further, the movement route of the position search device 130 is indicated by a dotted line, the measurement start point and the end point are indicated by a circular pointer, and the radio wave transmission device 10 is indicated by a star pointer.

FIG. 11 is a reference diagram illustrating an example of a search result of the position search system using the third implementation method.
In FIG. 11, the movement route of the position search device 130 is indicated by dotted lines and circles, the radio wave transmission device 10 is indicated by stars, and the maximum likelihood estimation point is indicated by x. 11A to 11F are arranged in time series, FIG. 11A shows the most recent existence probability distribution, and FIG. 11F shows the latest existence probability distribution. is there. In addition, the maximum likelihood estimation point (indicated by x) in FIG. 11 (f) represents the final estimated position.

As shown in FIG. 11B, in the position search device 130, the region where the variance of the evaluation function becomes small in the course of movement may be separated into, for example, around the point a, the point b, and the point c. That is, since the locations around the points a to c are located in the distribution regions having the same level of existence probability, the movement path determination device 37 determines the estimated position of the same level of existence probability in the traveling direction of the position search device 130. A plurality of moving directions are detected.
In such a case, the target radio wave source can be finally reached regardless of the direction in which the dispersion is reduced (the direction toward the vicinity of the points a to c).

  Here, the search result shown in FIG. 11C shows a result of selecting a movement route (indicated by a dotted line) toward the vicinity of the point a near the star where the radio wave transmitting device 10 actually exists. . After that, in the process of selecting the movement path so as to narrow the area where the evaluation function decreases around point a, the variance values around point b and point c eventually increase (Figure 11 (f)). For this reason, it is shown that the possibility that the radio wave transmitting device 10 exists around the point b and the point c has finally disappeared.

In addition, at the time shown in FIG. 11 (b), the moving route is selected not in the direction toward the vicinity of the point a but in the direction around the point b or the point c, and the number of observation points around the point b or the point c is increased. In this case, since the radio wave transmitter 10 is not actually located around the point b and the point c, the dispersion value shown in the equation (11) is also large.
Therefore, the possibility that the radio wave transmitting device 10 exists around the point b or the point c disappears quickly. Therefore, after the possibility around the point b and the point c disappears, the position of the radio wave transmission device 10 can be searched by selecting a moving route in the direction of the point a again.

  As a result of performing the positioning while adaptively selecting the movement route of the position search device 130 based on the third implementation method, the positioning accuracy could be improved to a positioning estimation error of about 20 m.

Here, the advantages and disadvantages of the first to third implementation methods will be described.
The first implementation method is a method in which it is not necessary to know a propagation attenuation constant depending on a propagation environment in advance, and a position search can be realized easily.
In addition, since it is not necessary to precisely determine the search area in advance, even when the rough position of the radio wave transmission device 10 is not known in advance, it is suitable for selecting a route while roughly grasping the location.
On the other hand, the saddle point cannot be determined unless the observation is finally performed in all directions.

In the second implementation method and the third implementation method, it is necessary to perform the maximum likelihood estimation operation (evaluation of the evaluation function) on the mesh-like candidate points. For this reason, when the rough position of the radio wave transmission device 10 is not known in advance, the search range must be expanded, and the required calculation amount increases.
On the other hand, as the movement route of the position search device 130, it is not necessary to perform observation so as to surround the four sides, and the positioning target can be finally identified by approaching from one direction, so the route selection procedure is simple. is there.

  Further, since the second implementation method is an algorithm based only on the maximum likelihood result, the estimation result is not easily narrowed down when there are a plurality of likely positions. On the other hand, the third implementation method can detect the position of the radio wave transmission device 10 as a probability distribution and reflect it in the route selection, thereby enabling more efficient route selection.

  Note that, in the present embodiment, an example in which the radio wave characteristic acquisition device 31 is one has been described, but the present invention is not limited to this, and for example, a plurality of position search devices respectively mounted on the plurality of moving bodies 20. 30 may be used.

As described above, according to the position search system according to the present embodiment, the number of radio wave characteristic acquisition devices can be increased using a single or a small number of radio wave characteristic acquisition devices 31 without increasing the number or location of the radio wave characteristic acquisition devices 31. In addition, the same positioning accuracy improvement effect as that obtained when the number of places is increased can be obtained, and the cost of the system can be reduced.
Further, the position search system according to the present embodiment is suitable for acquiring radio wave characteristics by maneuvering and moving the moving body 20 based on the estimated position information calculated by the estimated position calculation device 34. It is possible to move while adaptively selecting a radio wave characteristic observation point. Thereby, it is possible to realize more accurate positioning with a smaller number of observations or a shorter observation time.

DESCRIPTION OF SYMBOLS 10 Radio wave transmission apparatus 20 Mobile body 30 Position search apparatus 31 Radio wave characteristic acquisition apparatus 32 Position acquisition apparatus 33 Time acquisition apparatus 34 Estimated position calculation apparatus 35 Storage part 36 Operation part 37 Movement path determination apparatus

Claims (12)

A position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device,
A radio wave characteristic acquisition device for detecting radio wave characteristic information representing a radio wave characteristic of a radio wave transmitted by the radio wave transmitter;
A position acquisition device for detecting position information representing the position of the position search device;
An estimated position calculation device that calculates estimated position information that is information indicating a moving direction from the current position toward the radio wave transmission device based on the radio wave characteristic information and the position information;
A moving path determination for determining a moving direction of the position search device based on the estimated position information, generating notification information indicating the moving direction, and outputting the notification information to a notification unit provided in the moving body a device and the, the,
When the position search device is mounted on a moving body and moved, each of the plurality of radio wave characteristic information detected by the radio wave characteristic acquiring device and the plurality of radio wave characteristic information on the moving path of the moving body is obtained. Based on a plurality of the position information detected by the position acquisition device when detected, the estimated position information is calculated,
The estimated position calculation device includes:
Using the variance of a value obtained by subtracting each propagation distance attenuation equivalent amount from a plurality of radio wave characteristic information detected by the radio wave characteristic acquisition apparatus, an existence probability distribution representing the probability that the radio wave transmission apparatus exists is represented by the estimated position. Calculated as information,
The movement route determination device includes:
Based on the existence probability distribution, an area of a region where an evaluation function for evaluating the existence probability of the radio wave transmitting device is smaller than a first threshold is calculated, and whether or not the calculated area is equal to or greater than a second threshold. And when the calculated area is equal to or greater than the second threshold value, notification information indicating that the evaluation function moves in a direction to move to a small area is output to the notification unit, to that position search apparatus. A position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device,
A radio wave characteristic acquisition device for detecting radio wave characteristic information representing a radio wave characteristic of a radio wave transmitted by the radio wave transmitter;
A position acquisition device for detecting position information representing the position of the position search device;
An estimated position calculation device that calculates estimated position information that is information indicating a moving direction from the current position toward the radio wave transmission device based on the radio wave characteristic information and the position information;
A moving path determination for determining a moving direction of the position search device based on the estimated position information, generating notification information indicating the moving direction, and outputting the notification information to a notification unit provided in the moving body Equipment,
A time acquisition device for detecting time information representing a time when the radio wave characteristic information is detected by the radio wave characteristic acquisition device;
For the radio wave characteristic information, the position information detected by the position search device when the radio wave characteristic information is detected, the time information indicating the time when the radio wave characteristic information is detected, and the radio wave characteristic information; e Bei a storage unit that stores in association with the estimated position information calculated on the basis of the position information, and
When the position search device is mounted on a moving body and moved, each of the plurality of radio wave characteristic information detected by the radio wave characteristic acquiring device and the plurality of radio wave characteristic information on the moving path of the moving body is obtained. Based on a plurality of the position information detected by the position acquisition device when detected, the estimated position information is calculated,
The movement route determination device includes:
Of the differences between each of the position information detected by the position search device and the estimated position information associated with the latest time information among the estimated information, the smallest difference is obtained as a search result of the radio wave transmitting device. It is determined whether or not the target positioning accuracy is equal to or less than a predetermined target positioning accuracy, and the estimated position information associated with the newest time information and the estimated position associated with the second newest time information It is determined whether or not the amount of movement of the estimated position represented by the difference from the information is equal to or less than a predetermined third threshold, and the minimum difference is greater than the target positioning accuracy, or the transition When the amount of movement of the position is larger than the third threshold value, or both, the estimation represented by the estimated position information associated with the newest time information Position search apparatus you and outputting the notification information indicating that moves in a direction approaching the location on the notification unit. The estimated position calculation device includes:
The estimated position where the variance of the value obtained by subtracting the propagation distance attenuation equivalent amount from a plurality of radio wave characteristic information detected by the radio wave characteristic acquisition device is minimized is calculated as the estimated position information. 2. The position search apparatus according to 2. A position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device,
A radio wave characteristic acquisition device for detecting radio wave characteristic information representing a radio wave characteristic of a radio wave transmitted by the radio wave transmitter;
A position acquisition device for detecting position information representing the position of the position search device;
An estimated position calculation device that calculates estimated position information that is information indicating a moving direction from the current position toward the radio wave transmission device based on the radio wave characteristic information and the position information;
A moving path determination for determining a moving direction of the position search device based on the estimated position information, generating notification information indicating the moving direction, and outputting the notification information to a notification unit provided in the moving body Equipment,
A time acquisition device for detecting time information representing a time when the radio wave characteristic information is detected by the radio wave characteristic acquisition device;
For the radio wave characteristic information, the position information detected by the position search device when the radio wave characteristic information is detected, the time information indicating the time when the radio wave characteristic information is detected, and the radio wave characteristic information; e Bei a storage unit that stores in association with the estimated position information calculated on the basis of the position information, and
When the position search device is mounted on a moving body and moved, each of the plurality of radio wave characteristic information detected by the radio wave characteristic acquiring device and the plurality of radio wave characteristic information on the moving path of the moving body is obtained. Based on a plurality of the position information detected by the position acquisition device when detected, the estimated position information is calculated,
The movement route determination device includes:
The amount of change in the measurement position represented by the difference between the position information associated with the newest time information and the position information associated with the second most recent time information, the estimated position information associated with the newest time information, and the second And a change amount of the estimated position represented by a difference between the estimated position information associated with the new time information and determine whether or not the change amount of the measurement position is equal to or greater than the change amount of the estimated position. When the change amount of the measurement position is not equal to or greater than the change amount of the estimated position, the notification information indicating that the current traveling direction is maintained and moved is output to the notification unit,
When the change amount of the measurement position is greater than or equal to the change amount of the estimated position,
Of the differences between each of the position information detected by the position search device and the estimated position information associated with the latest time information among the estimated information, the smallest difference is obtained as a search result of the radio wave transmitting device. It is determined whether or not the target positioning accuracy is equal to or less than a predetermined target positioning accuracy, and the estimated position information associated with the newest time information and the estimated position associated with the second newest time information It is determined whether or not the amount of movement of the estimated position represented by the difference from the information is less than or equal to a predetermined fourth threshold, and the minimum difference is greater than the target positioning accuracy, or the transition When the amount of movement of the position is larger than the fourth threshold value, or in both cases, the estimation represented by the estimated position information associated with the newest time information Outputs the notification information indicating that moves in a direction approaching the location on the notification unit,
When the minimum difference is less than or equal to the target positioning accuracy and the movement amount of the transition position is less than or equal to the fourth threshold, the estimated position information represented by the estimated position information associated with the newest time information The surrounding area is equally divided by a predetermined number, and it is determined whether or not the position information is detected in each of the equally divided surrounding areas, and at least 1 in all of the divided surrounding areas. If the two pieces of position information are not detected, this means that the estimated position information represented by the estimated position information associated with the newest time information moves in a direction toward the divided surrounding area where the position information is not detected. position search apparatus you and outputting the notification information. The estimated position calculation device includes:
Using each of the plurality of radio wave characteristic information detected by the radio wave characteristic acquisition apparatus, each position information is weighted each time it is detected by the position acquisition apparatus, and the center of gravity position is used as the estimated position information. The position search apparatus according to claim 4 , wherein the position search apparatus calculates and updates the position search apparatus. A moving path determination for determining a moving direction of the position search device based on the estimated position information, generating notification information indicating the moving direction, and outputting the notification information to a notification unit provided in the moving body location search device according to any one of claims 1 to 5, further comprising a device. A position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device,
A radio wave characteristic acquisition device for detecting radio wave characteristic information representing a radio wave characteristic of a radio wave transmitted by the radio wave transmitter;
A position acquisition device for detecting position information representing the position of the position search device;
An estimated position calculation device that calculates estimated position information representing a position that is predicted as a position of the radio wave transmission device to be searched based on the radio wave characteristic information and the position information;
A moving path determination for determining a moving direction of the position search device based on the estimated position information, generating notification information indicating the moving direction, and outputting the notification information to a notification unit provided in the moving body An apparatus,
When the position search device is mounted on a moving body and moved, the radio wave characteristic information detected by the radio wave characteristic acquisition device in the moving path of the moving body and the position when the radio wave characteristic information is detected. Based on the position information detected by the acquisition device, to calculate the estimated position information,
The estimated position calculation device includes:
Using the variance of the value obtained by subtracting the propagation distance attenuation equivalent amount from the radio wave characteristic information detected by the radio wave characteristic acquisition device, an existence probability distribution representing the probability that the radio wave transmission device exists is calculated as the estimated position information. ,
The movement route determination device includes:
Based on the existence probability distribution, an area of a region where an evaluation function for evaluating the existence probability of the radio wave transmitting device is smaller than a first threshold is calculated, and whether or not the calculated area is equal to or greater than a second threshold. And when the calculated area is equal to or greater than the second threshold value, notification information indicating that the evaluation function moves in a direction to move to a small area is output to the notification unit, Position search device. A position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device,
A radio wave characteristic acquisition device for detecting radio wave characteristic information representing a radio wave characteristic of a radio wave transmitted by the radio wave transmitter;
A position acquisition device for detecting position information representing the position of the position search device;
An estimated position calculation device that calculates estimated position information representing a position that is predicted as a position of the radio wave transmission device to be searched based on the radio wave characteristic information and the position information;
A moving path determination for determining a moving direction of the position search device based on the estimated position information, generating notification information indicating the moving direction, and outputting the notification information to a notification unit provided in the moving body Equipment,
A time acquisition device for detecting time information representing a time when the radio wave characteristic information is detected by the radio wave characteristic acquisition device;
For the radio wave characteristic information, the position information detected by the position search device when the radio wave characteristic information is detected, the time information indicating the time when the radio wave characteristic information is detected, and the radio wave characteristic information; A storage unit that associates and stores the estimated position information calculated based on the position information,
When the position search device is mounted on a moving body and moved, the radio wave characteristic information detected by the radio wave characteristic acquisition device in the moving path of the moving body and the position when the radio wave characteristic information is detected. Based on the position information detected by the acquisition device, to calculate the estimated position information,
The movement route determination device includes:
Of the differences between each of the position information detected by the position search device and the estimated position information associated with the latest time information among the estimated information, the smallest difference is obtained as a search result of the radio wave transmitting device. It is determined whether or not the target positioning accuracy is equal to or less than a predetermined target positioning accuracy, and the estimated position information associated with the newest time information and the estimated position associated with the second newest time information It is determined whether or not the amount of movement of the estimated position represented by the difference from the information is equal to or less than a predetermined third threshold, and the minimum difference is greater than the target positioning accuracy, or the transition When the amount of movement of the position is larger than the third threshold value, or both, the estimation represented by the estimated position information associated with the newest time information Locator apparatus and outputting the notification information indicating that moves in a direction approaching the location on the notification unit. A position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device,
A radio wave characteristic acquisition device for detecting radio wave characteristic information representing a radio wave characteristic of a radio wave transmitted by the radio wave transmitter;
A position acquisition device for detecting position information representing the position of the position search device;
An estimated position calculation device that calculates estimated position information representing a position that is predicted as a position of the radio wave transmission device to be searched based on the radio wave characteristic information and the position information;
A moving path determination for determining a moving direction of the position search device based on the estimated position information, generating notification information indicating the moving direction, and outputting the notification information to a notification unit provided in the moving body Equipment,
A time acquisition device for detecting time information representing a time when the radio wave characteristic information is detected by the radio wave characteristic acquisition device;
For the radio wave characteristic information, the position information detected by the position search device when the radio wave characteristic information is detected, the time information indicating the time when the radio wave characteristic information is detected, and the radio wave characteristic information; A storage unit that associates and stores the estimated position information calculated based on the position information,
When the position search device is mounted on a moving body and moved, the radio wave characteristic information detected by the radio wave characteristic acquisition device in the moving path of the moving body and the position when the radio wave characteristic information is detected. Based on the position information detected by the acquisition device, to calculate the estimated position information,
The movement route determination device includes:
The amount of change in the measurement position represented by the difference between the position information associated with the newest time information and the position information associated with the second most recent time information, the estimated position information associated with the newest time information, and the second And a change amount of the estimated position represented by a difference between the estimated position information associated with the new time information and determine whether or not the change amount of the measurement position is equal to or greater than the change amount of the estimated position. When the change amount of the measurement position is not equal to or greater than the change amount of the estimated position, the notification information indicating that the current traveling direction is maintained and moved is output to the notification unit,
When the change amount of the measurement position is greater than or equal to the change amount of the estimated position,
Of the differences between each of the position information detected by the position search device and the estimated position information associated with the latest time information among the estimated information, the smallest difference is obtained as a search result of the radio wave transmitting device. It is determined whether or not the target positioning accuracy is equal to or less than a predetermined target positioning accuracy, and the estimated position information associated with the newest time information and the estimated position associated with the second newest time information It is determined whether or not the amount of movement of the estimated position represented by the difference from the information is less than or equal to a predetermined fourth threshold, and the minimum difference is greater than the target positioning accuracy, or the transition When the amount of movement of the position is larger than the fourth threshold value, or in both cases, the estimation represented by the estimated position information associated with the newest time information Outputs the notification information indicating that moves in a direction approaching the location on the notification unit,
When the minimum difference is less than or equal to the target positioning accuracy and the movement amount of the transition position is less than or equal to the fourth threshold, the estimated position information represented by the estimated position information associated with the newest time information The surrounding area is equally divided by a predetermined number, and it is determined whether or not the position information is detected in each of the equally divided surrounding areas, and at least 1 in all of the divided surrounding areas. If the two pieces of position information are not detected, this means that the estimated position information represented by the estimated position information associated with the newest time information moves in a direction toward the divided surrounding area where the position information is not detected. A position search apparatus that outputs notification information. A position search method by a position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device,
The radio wave characteristic acquisition device of the position search device,
Detecting radio wave characteristic information representing the radio wave characteristic of the radio wave transmitted by the radio wave transmitting device;
A position acquisition device of the position search device,
Detecting position information representing a position where the position search device exists when detecting the radio wave characteristic information;
The estimated position calculation device of the position search device,
Propagation from the radio wave characteristic information detected by the radio wave characteristic acquisition device when calculating the estimated position information representing the position predicted as the position of the radio wave transmission device to be searched based on the radio wave characteristic information and the position information Using the variance of the value obtained by subtracting the distance attenuation equivalent amount, the existence probability distribution representing the probability that the radio wave transmission device exists is calculated as the estimated position information,
The position search device is
The radio wave characteristic information detected by the radio wave characteristic acquisition device in the movement path of the mobile body by being mounted on the mobile body and detected by the position acquisition device when the radio wave characteristic information is detected. And calculating the estimated position information based on the position information
The movement path determination device of the position search device,
When determining the movement direction of the position search device based on the estimated position information, generating notification information representing the movement direction, and outputting the notification information to a notification unit provided in the moving body, Based on the existence probability distribution, the area of the region where the evaluation function for evaluating the existence probability of the radio wave transmitting device is smaller than the first threshold is calculated, and whether or not the calculated area is equal to or larger than the second threshold. And when the calculated area is equal to or larger than the second threshold value, notification information indicating that the evaluation function moves in a direction to move to a small area is output to the notification unit. Location search method. A position search method by a position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device,
The radio wave characteristic acquisition device of the position search device,
Detecting radio wave characteristic information representing the radio wave characteristic of the radio wave transmitted by the radio wave transmitting device;
A position acquisition device of the position search device,
Detecting position information representing a position where the position search device exists when detecting the radio wave characteristic information;
The time acquisition device of the position search device,
Detecting time information representing a time when the radio wave characteristic information is detected by the radio wave characteristic acquisition device;
The position search device is
For the radio wave characteristic information, the position information detected by the position search device when the radio wave characteristic information is detected, the time information indicating the time when the radio wave characteristic information is detected, and the radio wave characteristic information; Storing the estimated position information calculated based on the position information in association with each other;
The estimated position calculation device of the position search device,
Based on the radio wave characteristic information and the position information, to calculate estimated position information representing a position predicted as the position of the radio wave transmission device to be searched,
The position search device is
The radio wave characteristic information detected by the radio wave characteristic acquisition device in the movement path of the mobile body by being mounted on the mobile body and detected by the position acquisition device when the radio wave characteristic information is detected. And calculating the estimated position information based on the position information
The movement path determination device of the position search device,
When determining the movement direction of the position search device based on the estimated position information, generating notification information representing the movement direction, and outputting the notification information to a notification unit provided in the moving body, Among the differences between the position information detected by the position search device and the estimated position information associated with the newest time information among the estimated information, the smallest difference is permitted as a search result of the radio wave transmitting device. It is determined whether or not the value is equal to or less than a predetermined target positioning accuracy, and the estimated position information associated with the newest time information and the estimated position information associated with the second most recent time information It is determined whether or not the amount of movement of the estimated position represented by the difference between the difference is less than or equal to a predetermined third threshold, and the minimum difference is the target measurement. When it is larger than the accuracy, or when the movement amount of the transition position is larger than the third threshold value, or both, the estimated position represented by the estimated position information associated with the newest time information is approached. A position search method characterized in that notification information indicating moving in a direction is output to the notification unit. A position search method by a position search device that receives a radio wave transmitted by a radio wave transmission device and searches for a position of the radio wave transmission device,
The radio wave characteristic acquisition device of the position search device,
Detecting radio wave characteristic information representing the radio wave characteristic of the radio wave transmitted by the radio wave transmitting device;
A position acquisition device of the position search device,
Detecting position information representing a position where the position search device exists when detecting the radio wave characteristic information;
The time acquisition device of the position search device,
Detecting time information representing a time when the radio wave characteristic information is detected by the radio wave characteristic acquisition device;
The position search device is
For the radio wave characteristic information, the position information detected by the position search device when the radio wave characteristic information is detected, the time information indicating the time when the radio wave characteristic information is detected, and the radio wave characteristic information; Storing the estimated position information calculated based on the position information in association with each other;
The estimated position calculation device of the position search device,
Based on the radio wave characteristic information and the position information, to calculate estimated position information representing a position predicted as the position of the radio wave transmission device to be searched,
The position search device is
The radio wave characteristic information detected by the radio wave characteristic acquisition device in the movement path of the mobile body by being mounted on the mobile body and detected by the position acquisition device when the radio wave characteristic information is detected. And calculating the estimated position information based on the position information
The movement path determination device of the position search device,
When determining the movement direction of the position search device based on the estimated position information, generating notification information representing the movement direction, and outputting the notification information to a notification unit provided in the moving body,
The amount of change in the measurement position represented by the difference between the position information associated with the newest time information and the position information associated with the second most recent time information, the estimated position information associated with the newest time information, and the second And a change amount of the estimated position represented by a difference between the estimated position information associated with the new time information and determine whether or not the change amount of the measurement position is equal to or greater than the change amount of the estimated position. When the change amount of the measurement position is not equal to or greater than the change amount of the estimated position, the notification information indicating that the current traveling direction is maintained and moved is output to the notification unit,
When the change amount of the measurement position is greater than or equal to the change amount of the estimated position,
Of the differences between each of the position information detected by the position search device and the estimated position information associated with the latest time information among the estimated information, the smallest difference is obtained as a search result of the radio wave transmitting device. It is determined whether or not the target positioning accuracy is equal to or less than a predetermined target positioning accuracy, and the estimated position information associated with the newest time information and the estimated position associated with the second newest time information It is determined whether or not the amount of movement of the estimated position represented by the difference from the information is less than or equal to a predetermined fourth threshold, and the minimum difference is greater than the target positioning accuracy, or the transition When the amount of movement of the position is larger than the fourth threshold value, or in both cases, the estimation represented by the estimated position information associated with the newest time information Outputs the notification information indicating that moves in a direction approaching the location on the notification unit,
When the minimum difference is less than or equal to the target positioning accuracy and the movement amount of the transition position is less than or equal to the fourth threshold, the estimated position information represented by the estimated position information associated with the newest time information The surrounding area is equally divided by a predetermined number, and it is determined whether or not the position information is detected in each of the equally divided surrounding areas, and at least 1 in all of the divided surrounding areas. If the two pieces of position information are not detected, this means that the estimated position information represented by the estimated position information associated with the newest time information moves in a direction toward the divided surrounding area where the position information is not detected. A position search method characterized by outputting notification information.

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