WO2017150323A1

WO2017150323A1 - Location estimation system

Info

Publication number: WO2017150323A1
Application number: PCT/JP2017/006772
Authority: WO
Inventors: 三浦　龍; 滝沢　賢一; 原　晋介; 文枝小野
Original assignee: 国立研究開発法人情報通信研究機構
Priority date: 2016-02-29
Filing date: 2017-02-23
Publication date: 2017-09-08
Also published as: JP6742589B2; JP2017156102A

Abstract

The present invention can estimate the location of a target object without proceeding through a step for accurately measuring the Doppler shift, etc. of wireless signals and, for the improvement of the precision of the estimations thereof, comprises: a flying body 30 that, in the process of flying an externally controllable flight trajectory, continuously receives wireless signals transmitted from a signal transmitter 20 that is attached to a target object; an observation unit 33 that observes trends in changes, relative to position, in data related to the wireless signals received by the flying body 30; and a location estimation unit 35 that finds condition-satisfying locations at which the observed relative trends in changes in the data satisfy preset conditions, that, in the process of the flying body 30 being made to fly different flight trajectories, finds at least 3 condition-satisfying locations from relative trends in changes from at least 3 observations made by the observation unit 33, and estimates the location of the target object on the basis of at least 3 plane equations into which have been respectively incorporated three-dimensional position information and a directional vector for the condition-satisfying locations.

Description

Position estimation system

The present invention relates to a position estimation system that estimates the position of an object that is stationary or slightly moving.

In recent years, there has been an increasing social need for technology for accurately estimating the current position of a person in order to search for an elderly person who has lost his or her whereabouts due to drought or to search for a victim. In addition, the present invention is not limited to the case where the measurement target is a human being, and a technique for accurately estimating the current position of a wild animal is also required in order to perform an ecological exploration of, for example, a wild animal with high accuracy.

In order to improve the certainty of the estimation, a radio signal transmitted from a stationary object is received by the moving object, and the position from the moving object to the object is determined based on information obtained from the received signal. A technique for estimating a position by obtaining a distance and an angle has also been proposed (see, for example, Patent Document 1). For example, by assuming that the oscillation frequency of a radio signal transmitted from an object is known and the speed of the moving object is known, the frequency of the radio signal received at an arbitrary position of the moving object is measured. The angle from the moving object to the object can be estimated based on the Doppler shift amount. By performing these processes at a plurality of locations, the position of the object can also be estimated.

Japanese Patent Publication No.7-1117580

However, according to the technique disclosed in Patent Document 1, when the moving body tries to estimate the angle to the target of position estimation at an arbitrary position, in addition to the oscillation frequency of the radio signal oscillated from the target, It is necessary to accurately detect the position where the signal is received, the moving direction of the moving body at the position, and the moving speed at the position. Furthermore, according to the technique disclosed in Patent Document 1, it is necessary to accurately measure the Doppler shift amount in order to perform such position estimation.

The oscillation frequency of the radio signal transmitted from the object can be easily detected if the signal is received when the moving object is stationary, and the position and traveling direction of the moving object can be easily determined using GPS or the like. Can be obtained. However, it is actually difficult to accurately measure the moving speed of the moving body at the measurement position and the Doppler shift amount of the radio signal.

Therefore, the present invention has been devised in view of the above-described problems, and the object of the present invention is to perform a step of accurately measuring the moving speed of the moving body and the Doppler shift amount of the radio signal. An object of the present invention is to provide a position estimation system capable of estimating the position of an object and capable of remarkably improving the estimation accuracy.

In order to solve the above-described problems, the present inventors have invented a position estimation system having the following configuration.

A position estimation system according to a first aspect of the present invention is a position estimation system for estimating the position of an object that is stationary or slightly moving, and in the process of flying on a flight trajectory that can be controlled from the outside. A vehicle that continuously receives a radio signal transmitted from a signal transmitter attached to the vehicle, three-dimensional position information of each position on the flight trajectory of the aircraft, and 3 of the flight trajectory at the position. The vehicle position information detecting means for detecting a dimensional direction vector, the observation means for observing the relative change tendency of the data relating to the radio signal received by the flying object with respect to the position, and the observation means A condition satisfying position in which the relative change tendency of data satisfies a preset condition is obtained, and three-dimensional position information at the condition satisfying position and A position estimation means for acquiring a direction vector from the flying object position information acquisition means and substituting it into a plane equation, wherein the position estimation means performs the observation in the process of flying the flying objects on different flight trajectories. The position satisfying the condition is obtained at three or more locations from the relative change tendency observed three times or more from the means, and the three-dimensional position information and the direction vector at each position satisfying the condition are substituted. The position of the object is estimated based on an equation of two or more planes.

The position estimation system according to a second invention is the position estimation system according to the first invention, wherein the position estimation means determines the position closest to the object from the relative change tendency of the data observed by the observation means. It is characterized by being a condition satisfying position.

In a position estimation system according to a third aspect based on the second aspect, the observation means observes a relative change tendency of the propagation delay amount as data relating to the radio signal, and the position estimation means is determined by the observation means. The position where the observed propagation delay amount is minimized is the position satisfying the above condition.

In a position estimation system according to a fourth aspect based on the second aspect, the observation means observes a relative change tendency of the received power of the radio signal as data relating to the radio signal, and the position estimation means comprises the observation The position where the received power observed by the means is maximized is the position satisfying the above condition.

In a position estimation system according to a fifth aspect based on the first aspect, the observation means observes a relative change tendency of the frequency of the radio signal as data relating to the radio signal, and the position estimation means is the target object. with previously to obtain frequency f ₀ of the outgoing radio signals from the observed frequency by the observation means, characterized in that the above conditions satisfying position comes closest position to the frequency f _0.

The position estimation system according to a sixth aspect of the present invention is the position estimation system according to the first aspect, wherein the observation unit continues to acquire data relating to a radio signal until the condition-satisfying position can be detected. After the condition satisfying position can be detected, the flight is changed to another flight trajectory and continues to fly.

According to the position estimation system to which the present invention having the above-described configuration is applied, the signal is transmitted in the direction of 90 ° from the flight direction only by following the relative change tendency of the data related to the radio signal observed by the observation unit 33. It is possible to specify a condition satisfying position on the flight trajectory k where the position U of the aircraft 20 exists. Then, substituting the three-dimensional position information and the direction vector at the condition satisfying position into the plane equation is repeated three or more times between different flight trajectories to estimate the position of the object. be able to.

In the actual process, it is possible to estimate the position of the object simply by following the relative change tendency of the data without going through the step of accurately measuring the data related to the radio signal. For this reason, the position of the object can be estimated without going through the steps of accurately measuring the moving speed of the moving object and the Doppler shift amount of the radio signal as in the prior art, and the estimation accuracy is greatly improved. It becomes possible to make it.

It is a figure which shows the whole structure of the position estimation system to which this invention is applied. It is a block block diagram of a signal transmitter and a flying body. It is a figure for demonstrating the concept of the position estimation in the position estimation system to which this invention is applied. It is a figure which shows the example in the case of flying the one flight track | orbit k by a flying body. It is a figure which shows the example which receives the radio signal transmitted from a signal transmitter, making a flying body fly on the flight track set to linear form. It is a figure which shows the relative change tendency of the data regarding a radio signal on the vertical axis as each position of a flight trajectory in the shape of a straight line with the horizontal axis directed in the flight direction.

Hereinafter, an embodiment for implementing a position estimation system to which the present invention is applied will be described in detail with reference to the drawings.

The position estimation system 10 to which the present invention is applied includes a signal transmitter 20 and an aircraft 30 as shown in FIG.

FIG. 2A shows the configuration of the signal transmitter 20. The signal transmitter 20 includes a signal generation unit 21 that generates a signal having a predetermined frequency, and an antenna 22 connected to the signal generation unit 21. A signal having a predetermined frequency generated by the signal generation unit 21 is converted into a radio wave by the antenna 22 and transmitted in all directions. Hereinafter, the radio wave transmitted from the antenna 22 is referred to as a radio signal.

Incidentally, the signal transmitter 20 includes the signal generation unit 21 and the antenna 22 and may be embodied in any form as long as it transmits a radio signal having a predetermined frequency. For example, it may be embodied as a beacon transmitter that transmits only a beacon, or can perform wireless communication such as a mobile phone, a smartphone, a wearable terminal, a tablet terminal, or a personal computer (PC). It may be embodied as a communication terminal. This signal transmitter 20 is carried or attached to a target whose position is actually to be estimated. If the object whose position is to be estimated is a person such as an elderly person or a child, the person carries the signal transmitter 20. If the object whose position is to be estimated is an animal, the signal transmitter 20 is attached to the animal. Incidentally, the signal transmitter 20 is not limited to the case where it is attached to such a freely moving life form, and may be attached to a plant such as a tree. The signal transmitter 20 may be attached to a non-life object such as a building structure, a building material, a stone, a road, a bridge, a tunnel, or various infrastructures.

The object to which the signal transmitter 20 is attached is assumed to be stationary at the time of position estimation by the position estimation system 10 to which the present invention is applied, but is not limited to this and moves slightly. There may be.

The position estimation system 10 to which the present invention is applied is a system for accurately detecting the position of the signal transmitter 20 and for grasping the position of the target to which the signal transmitter 20 is actually attached. It is.

The flying object 30 is an arbitrary flying object capable of autonomous flight. The flying body 30 is embodied by a fixed wing aircraft, a rotary wing aircraft, an airship, a balloon, a drone, an unmanned aerial vehicle (UAV), a helicopter, an airplane, or the like. The flying object 30 may be an unmanned person that is not boarded by humans, or may be capable of boarding humans. However, it is assumed that the flying object 30 does not fly at random, but its flight trajectory can be controlled from the outside.

FIG. 2B shows the configuration of the flying object 30. The flying object 30 includes an airframe control unit 31, a radio signal receiving unit 32 connected to the antenna 29, an observation unit 33 connected to the radio signal receiving unit 32, an information detection unit 34, an observation unit 33, and information. A position estimation unit 35 connected to the detection unit 34, an operation unit 36 and a control signal reception unit 37 connected to the airframe control unit 31, an information storage unit 38 and an estimated information transmission unit connected to the position estimation unit 35 39.

The aircraft control unit 31 controls the propulsion system and the steering system (both not shown) of the flying object 30 based on the flight trajectory and flight control commands specified in the flight plan input in advance. The body control unit 31 acquires these flight plans and flight control commands via the operation unit 36 or the control signal receiving unit 37. The airframe control unit 31 specifies the flight trajectory by specifying the flight altitude and the flight direction based on these flight plans and flight control commands, and can fly at the specified altitude and coordinates. . The aircraft control unit 31 also designates the flight speed based on these flight plans and flight control commands.

The operation unit 36 is a user interface for the user to actually input a flight plan and a flight control command. Specifically, the operation unit 36 includes a keyboard, buttons, a touch panel, a mouse, a switch, and the like. However, if the flying object 30 is not unmanned but is a person on board, a control stick is used. Or cockpit. The flight plan and flight control command input via the operation unit 36 are sent to the airframe control unit 31, and the flight trajectory and the like of the aircraft 30 are determined along this.

The control signal receiving unit 37 is a device for receiving a flight plan and a flight control command transmitted via a controller (not shown) or a base station (not shown) that is operated remotely. These flight plans and flight control commands are transmitted from the outside by wired communication or wireless communication. If these flight control commands and the like are transmitted by wireless communication, the control signal receiving unit 37 is configured as an antenna for receiving them. The control signal receiving unit 37 transmits a flight plan and a flight control command to the airframe control unit 31. The body control unit 31 receives the flight plan and the flight control command, and determines the flight trajectory of the flying body 30 according to the flight plan and the flight control command.

In other words, the flying object 30 is controlled not to fly in an arbitrary flight trajectory because the flight altitude and flight direction are controlled based on a flight control command or the like input based on the user's intention. It will fly in the flight trajectory according to the intention. That is, it is assumed that the flight trajectory of the flying object 30 is controlled from the outside.

The radio signal receiving unit 32 receives a radio signal transmitted from the signal transmitter 20 via the antenna 29. The radio signal receiving unit 32 outputs the received radio signal to the observation unit 33.

The observation unit 33 observes the data related to the radio signal transmitted from the radio signal reception unit 32 based on various observation criteria. The data related to the radio signal herein may be any data as long as it relates to the radio signal, and includes, for example, the propagation delay amount (propagation delay time), received power, frequency, and the like of the radio signal. The observation unit 33 obtains data related to the radio signal and then continues to observe the change tendency in a time series. The observation unit 33 notifies the position estimation unit 35 of the observation result of the data related to the radio signal.

The information detection unit 34 is a part for detecting various information in the flying object 30. The information detection unit 34 includes one or a plurality of measuring instruments, for example, an apparatus for determining the engine speed, an attitude sensor, an altimeter, an acceleration sensor, an airspeed meter, a magnetic compass, and a gyrocompass. It is composed of compass and the like. Further, the information detection unit 34 may be a person having a GPS (Global Positioning System) device in order to detect the position information of the flying object 30 at the present time. In this GPS device, the latitude, longitude, altitude, and time information of the aircraft 30 at the current time are acquired. Incidentally, as a means for detecting such position information, a satellite positioning system other than the GPS device may be used. Further, when acquiring time information, a radio timepiece other than the GPS device may be used. According to the information detection unit 34 having these measuring instruments and devices, at least three-dimensional position information of each position on the flight trajectory of the flying object 30 can be acquired. In addition, a three-dimensional direction vector of the flight trajectory at the position can be detected. The information detection unit 34 detects this direction vector using, for example, a GPS or a geomagnetic sensor. The information detection unit 34 transmits at least the acquired three-dimensional position information of each position on the flight trajectory of the flying object 30 and the three-dimensional direction vector of the flight trajectory at the position to the position estimation unit 35.

The position estimation unit 35 receives the observation result of the data related to the radio signal from the observation unit 33. Further, the position estimation unit 35 receives the three-dimensional position information of each position on the flight trajectory of the flying object 30 and the three-dimensional direction vector of the flight trajectory at the position from the information detection unit 34. The position estimation unit 35 estimates the position of the signal transmitter 20 while referring to the position information and the direction vector based on the observation result of the data. Details of the position estimation will be described later. The position estimation unit 35 outputs the estimated position of the signal transmitter 20 to the information storage unit 38 and / or the estimated information transmission unit 39.

The information storage unit 38 includes a semiconductor memory element such as (Flash Memory), a storage device such as a hard disk and an optical disk, and the like. The information storage unit 38 stores information regarding the estimated position of the signal transmitter 20 transmitted from the position estimation unit 35. The information storage unit 38 also stores the observation result of the data related to the radio signal transmitted from the observation unit 33 and the position information and the direction vector transmitted from the information detection unit 34 as necessary. Information relating to the estimated position of the signal transmitter 20 stored in the information storage unit 38, observation results of data relating to radio signals, position information and direction vectors are read out as needed under the control of the position estimating unit 35 and the like.

The estimated information transmitting unit 39 transmits information on the estimated position of the signal transmitter 20 transmitted from the position estimating unit 35 to an external base station, a controller, etc. (not shown) through wireless communication or wired communication.

Next, the concept of position estimation in the position estimation system 10 to which the present invention is applied will be described.

According to the position estimation system 10 to which the present invention is applied, as shown in FIG. 3, the flying object 30 spans the

flight trajectories

1, 2, 3,... K,. Let it fly. The flying body 30 continues to receive a radio signal having a frequency f ₀ [Hz] transmitted from the signal transmitter 20 in the process of flying in each flight trajectory k. Then, the flying object 30 estimates the position of the signal transmitter 20 located in the 90 ° direction with respect to the direction of the flight trajectory by observing data regarding the received radio signal. In the flight trajectory 1 referred to in FIG. 3, the coordinates U of the signal transmitter 20 are located at 90 ° with respect to the direction of the flight trajectory at Q ₁ . Similarly, in the flight trajectory 2, the U of the signal transmitter 20 is located at 90 ° with respect to the direction of the flight trajectory at Q ₂ . In the flight trajectory k, the U of the signal transmitter 20 is located at 90 ° with respect to the direction of the flight trajectory at Q _k . Hereinafter, the three-dimensional coordinates of the signal transmitter 20 as the estimation target are given by U = [X, Y, Z].

FIG. 4 shows an example in which one flying trajectory k is caused to fly by the flying object 30. The direction vector in the flight direction of the flying object 30 in the flight path _k is given by d _k = [a _k , b _k , c _k ]. Further, the position vector of the position Q _k on the flight trajectory k where the position U of the signal transmitter 20 exists in the direction of 90 ° from the flight direction is given by Q _k = [x _k , y _k , y _k ]. It is done. That is, the direction vector d _k = [a _k , b _k , c _k ] indicates the flight direction of the flying object 30 at the position Q _k on the flight trajectory k, and the direction that forms 90 ° from the position Q _k. Therefore, the position U of the signal transmitter 20 exists.

According to the position estimation system 10 to which the present invention is applied, a signal is transmitted in the direction of 90 ° from the flight direction d _k = [ _ak , b _k , c _k ] while the flying object 30 is flying on the flight path k. The operation of searching for the position Q _k on the flight trajectory k where the position U of the transmitter 20 exists will be performed.

In the example of FIG. 5, an example in which a radio signal transmitted from the signal transmitter 20 is received while the flying object 30 is flying on the flight trajectory k set linearly is shown. In the flight trajectory k, the flying object 30 passes through the positions Q _k−1 ,... Q _k-2 ... Q _k-3 , and is linear in the direction vector d _k = [ _ak , b _k , c _k ]. In the case of flying in a shape, the position Q _k-2 is the closest to the position U. Then, the position U of the signal transmitter 20 is in a direction forming 90 ° with respect to the direction vector d _k = [a _k , b _k , c _k ] from the position Q _k−2 closest to the position U. Exists. In FIG. 5, the position Q _k-2 is closest to the position U, and the perpendicular line drawn from the position U toward the flight trajectory of this direction vector d _k = [a _k , b _k , c _k ]. The position is the position Q _k-2 .

For this reason, the position Q _k-2 on the flight trajectory k closest to the position U is analyzed via a radio signal transmitted from the signal transmitter 20. For example, when the received power of a radio signal is analyzed, the flying object 30 passes through the positions Q _k−1 ,... Q _{k− 2,} Q _k−3 and the direction vector d _k = [ _ak , b _k , c _k ], the distance from the position U gradually decreases from the position Q _k-1 to the position Q _k-2 , and the received power gradually increases accordingly. growing. On the other hand, since the distance from the position U gradually increases until the flying object 30 reaches the position Q _k-3 from the position Q _k-2 , the received power gradually decreases accordingly. As a result, the peak of the received power appears just at the position Q _k-2 .

Accordingly, the flight vehicle 30 is positioned Q _k-1, flight _{_{··· Q k-2 ··· Q k}} -3 through the direction vector _{_{d k = [a k, b}} k, c k] straight in the direction of In this process, it is possible to obtain the position information of the position Q _k-2 by following the relative change tendency of the received power and specifying the position of the peak. As a result, the flight trajectory in which the position U of the signal transmitter 20 exists in the direction of 90 ° from the flight direction d _k = [a _k , b _k , c _k ] simply by following the relative change tendency of the received power. It is possible to specify a position Q k on _k (hereinafter, a position Q _k satisfying such a condition is referred to as a condition satisfying position).

In FIG. 6, the horizontal axis represents each position of the linear flight trajectory k with the flight direction d _k = [a _k , b _k , c _k ], and the vertical axis represents the relative change tendency of the data related to the radio signal. Show. 6A shows the propagation delay amount as data related to the radio signal constituting the vertical axis, FIG. 6B shows the received power described above as data related to the radio signal constituting the vertical axis, and FIG. Respectively assign reception frequencies as data relating to radio signals constituting the vertical axis.

In the example of FIG. 6A, the propagation delay amount (propagation delay time) of the radio signal is measured along a linear flight trajectory in the flight direction d _k = [a _k , b _k , c _k ]. Go. A position Q _{k at} which the propagation delay amount is minimum is a condition satisfying position.

In the example of FIG. 6B, the position Q _{k at} which the reception power is maximized is the condition satisfaction position as described above.

In the example of FIG. 6C, when utilizing the fact that the received Doppler shift amount received by the radio signal is 0, the frequency of the radio signal is observed and the frequency is transmitted from the signal transmitter 20 to the frequency f _0. The position closest to is the condition satisfaction position.

In the example of FIG. 6, it is not necessary to measure an absolute accurate value for the vertical axis in any case, and a change tendency relative to the position of the horizontal axis is identified, and its maximum value, minimum value By specifying a value or a place closest to the frequency f ₀ , a condition satisfaction position can be obtained. Therefore, in obtaining the condition satisfaction position, it is not necessary to perform detailed calibration of the observation unit 33 that observes data related to the radio signal, and it is possible to prevent the observation from becoming complicated.

Note that the method for obtaining the condition satisfaction position is not limited to these, and may be obtained based on any other method. In other words, any method can be used as long as other data capable of identifying the distance from the position U is observed from the radio signal, and the condition satisfying position where the distance is closest can be identified from the relative change tendency. It may be a thing. Alternatively, the relative change tendency of the observed data is followed, and a condition satisfying a preset condition, such as a condition of being closest to the frequency f ₀ as shown in FIG. Any other method may be applied as long as it is.

The coordinates Q _k = [x _k , y _k , y _k ] at the condition satisfying position Q _k determined in this way are included, and the direction vector d _k = [a _k , b _k of the flight trajectory k of the flying object 30 is included. , C _k ] perpendicular to the plane P _k includes the three-dimensional coordinates U = [X, Y, Z] of the signal transmitter 20. The coordinates Q _k = [x _k , y _k , y _k ] at the condition satisfaction position Q _k can be obtained from the information detection unit 34, and the direction vector d _k = [a _k , b _k , c _k ] is already known, so if an arbitrary point on P _k is P = [x, y, z], the plane equation is d _k · (P−Q _k ) = 0, so that (1) It can represent with Formula.

... (1)

Further, if P = [x, y, z] is U = [X, Y, Z] for an arbitrary point on this P _k , x = X is substituted in this equation (1), and y Substituting = Y and substituting z = Z can be expressed by the following equation (2).

(2)

However, since this equation (2) has three variables X, Y, and Z, a solution for these variables X, Y, and Z cannot be obtained unless there are at least three such plane equations in total. It will be.

FIG. 3 depicts three planes P _k perpendicular to the direction vector d _k = [a _k , b _k , c _k ] of the flight trajectory _k over the planes P ₁ , P ₂ and P _k . Is. These planes P ₁ , P ₂ and P _k are directed in directions in which the direction vector d ₁ of the flight trajectory 1 perpendicular to the plane, the direction vector d _{2 of} the flight trajectory ₂ and the direction vector d _k of the flight trajectory k are different from each other. It has been extended. When there is no estimation error, three different planes P ₁ , P ₂ , and P _k intersect at one point, and that point becomes the estimated value of U. Actually, the three-dimensional coordinates U = [X, Y, Z] of this U are based on the above-described method, and the equation of the plane of the equation (2) is created for each plane P ₁ , P ₂ , P _k , and the simultaneous It can be obtained by solving the equation.

Next, an actual position estimation operation in the position estimation system 10 to which the present invention is applied will be described.

Before the position estimation system 10 is operated, the signal transmitter 20 is attached in advance to an object for position estimation. The signal generator 21 in the signal transmitter 20 generates a signal having a frequency f ₀ constantly or intermittently. This generated signal is transmitted as a radio signal through the antenna 22 constantly or intermittently.

The user of the position estimation system 10 inputs a flight plan or a flight control command by operating the operation unit 36 or via a base station or a controller (not shown). Thereby, the flight trajectory of the flying object 30 can be controlled on the user side. The aircraft control unit 31 that has received the flight control command or the like causes the aircraft 30 to fly toward the flight path k based on the command.

In the process of flying the flying object 30 toward the flight trajectory k, the information detection unit 34 at least three-dimensional position information of the position of the flying object 30 on the flight trajectory and the three-dimensional direction of the flight trajectory at the position. The vector is continuously acquired and is output to the position estimation unit 35. Further, in the process of flying the flying object 30 toward the flight path k, the wireless signal transmitted from the antenna 22 of the signal transmitter 20 is received by the wireless signal receiving unit 32 via the antenna 29 in the flying object 30, and further It is sent to the observation unit 33. As described above, the observation unit 33 observes any data including the reception voltage, the propagation delay time, and the frequency from the radio signal.

These operations are repeatedly performed in the process of flying the flying object 30 toward the flight path k. As a result, for each position on the flight trajectory k, the three-dimensional position information and the three-dimensional direction vector of the flight trajectory at that position can be acquired sequentially. In addition, the observation unit 33 sequentially observes data related to radio signals such as received voltage at each position on the flight trajectory k, thereby obtaining a relative change tendency with the horizontal axis as shown in FIG. can do.

The relative estimation tendency of the data regarding the radio signal observed by the observation unit 33 is sequentially input to the position estimation unit 35. At the same time, three-dimensional position information and a three-dimensional direction vector of the flight trajectory k at the position are input from the information detection unit 34 to each position on the flight trajectory k. The position estimation unit 35 performs an operation of specifying the condition satisfaction position Q _k based on the relative change tendency of the data regarding the radio signal. If the condition satisfaction position Q _k can be specified, the coordinates Q _k = [x _k , y _k , y _k of the condition satisfaction position Q _k out of the three-dimensional position information input from the information detection unit 34. ], And the three-dimensional direction vector d _k = [a _k , b _k , c _k ] of the three flight trajectories k input from the information detection unit 34 is acquired. The position estimation unit 35 obtains the coordinates Q _k = [x _k , y _k , y _k ] of the acquired condition satisfaction position Q _k and the three-dimensional direction vector d _k = [a _k , b _k , c _k ]. By substituting into equation (2), a plane equation can be obtained.

Next, the user of the position estimation system 10 sets the flight path to be different from the above-described flight path k by operating the operation unit 36 or via a base station or a controller (not shown). Then, the flying object 30 is caused to fly and the same operation as described above is performed. By executing this three or more times, a change tendency of data regarding the relative radio signal is acquired three or more times from the observation unit 33 via the flying object 30 that has been flying on different flight trajectories k. It is possible to obtain three or more conditions satisfying conditions. In addition, it is possible to obtain three or more plane equations into which three-dimensional position information and direction vectors at each condition-satisfying position are substituted, and by solving this, it is possible to estimate the position U of the object. Become.

In this way, according to the position estimation system 10 to which the present invention is applied, the signal in the direction of 90 ° from the flight direction can be obtained only by following the relative change tendency of the data related to the radio signal observed by the observation unit 33. It is possible to specify a condition satisfying position on the flight trajectory k where the position U of the transmitter 20 exists. Then, substituting the three-dimensional position information and the direction vector at the condition satisfying position into the plane equation is repeated three or more times between different flight trajectories to estimate the position of the object. be able to.

The position estimation unit 35 may estimate the position U of the object and then store it in the information storage unit 38 or display it on a display screen (not shown). Alternatively, the position estimation unit 35 may transmit the estimated position U of the target object via an estimation information transmission unit 39 to an external base station or controller (not shown) via wireless communication or wired communication.

In the above-described embodiment, the three-dimensional direction vector d _k = [a _k , b _k , c _k ] of the flight trajectory k is detected by the information detection unit 34 and is sent to the position estimation unit 35. The case of transmission has been described as an example, but the present invention is not limited to this. When such a direction vector d _k can be specified based on a flight plan or flight control command input by the user from the operation unit 36 or the like, it may be obtained by providing it to the position estimation unit 35. .

In the above-described embodiment, the case where there is no estimation error has been described as an example. However, when there is an estimation error, the following estimation may be performed.

In general, when there is such an estimation error, the planes do not intersect at one point. The distance from the true position U = [X, Y, Z] of U to the plane P _k is given by the following equation (3).

(3)

For this reason, if this distance is considered as an error and U is estimated by the least square estimation method, it can be obtained by the following equation (4).

(4)

In the present invention, the moving speed of the flying object 30 is measured by the information detecting unit 34, or the moving speed of the object is measured by a measuring means (not shown), and this is stored in the information storing unit 38, The number of flight trajectories k may be determined based on one or more of the moving speed of 30 and the moving speed of the object.

Further, one or more of the observation unit 33 and the position estimation unit 35 may be mounted in an external base station or controller (not shown) instead of being provided in the aircraft 30. In such a case, when a radio signal is received by the radio signal receiving unit 32, it is transmitted to a base station or a controller (not shown) via the estimation information transmitting unit 39, and an observation unit mounted therein 33, the position is estimated via the position estimation unit 35.

According to the present invention, it is assumed that the flight trajectory k of the air vehicle 30 is a straight line. However, when the flight trajectory k is switched from the flight trajectory k to another flight trajectory k + 1, Although it may be made to take off and land each time, it may be switched by changing the flight trajectory of the flying object 30 on the way.

In such a case, when the position where the condition is satisfied is followed by the position of the received power as shown in FIG. 6B, if the received power is measured and if this continues to decrease as the flying object 30 advances, the flying object 30 It means that it is gradually separated from the condition satisfaction position. In such a case, even if the flying object 30 continues to fly on the flight trajectory, it cannot reach the condition satisfying position where the received power is maximized, so the flight of the flying object 30 on the flight trajectory is stopped.

On the other hand, as a result of measuring the received power, if the aircraft 30 continues to increase as the aircraft 30 advances, it means that the aircraft 30 is gradually approaching the condition satisfaction position. In such a case, the flying object 3 will continue to fly on its flight path. During the flight, the flying object 3 continues to detect the received power. As a result, when the received power that has been raised up until now as the flying object 30 starts to decrease, the peak as shown in FIG. It means that the position has appeared. Such a peak position corresponds to the above-mentioned condition satisfaction position. At the stage where the condition satisfaction position can be specified, the flying object 30 can change to another flight trajectory and perform the same observation. In the above example, the case where the received power is observed as data relating to a radio signal has been described as an example. However, the same applies to other examples, and the flying object 30 appears until a position where the propagation delay amount is minimized appears. The flight may be continued, or the flight may be continued until the position where the observed frequency is closest to the frequency f ₀ can be identified.

In other words, according to the present invention, data relating to a radio signal is continuously acquired in real time, whether or not a condition satisfying position appears is determined while flying the flying object 30, and the flight trajectory is maintained until the condition satisfying position can be confirmed. You may make it fly linearly. Then, the flying object 30 may be changed to another flight trajectory after the observation unit 33 can confirm the condition satisfaction position, and may continue to fly as it is. In other words, whether or not the condition satisfaction position is specified may be used for the determination of the flight trajectory change.

DESCRIPTION OF SYMBOLS 10 Position estimation system 20 Signal transmitter 21

Signal generation part

22, 29 Antenna 30 Aircraft body 31 Airframe control part 32 Radio signal reception part 33 Observation part 34 Information detection part 35 Position estimation part 36 Operation part 37 Control signal reception part 38 Information storage Part 39 Estimated information transmitter

Claims

In a position estimation system for estimating the position of an object that is stationary or slightly moving,
A vehicle that continuously receives a radio signal transmitted from a signal transmitter attached to the object in the process of flying on a flight trajectory that can be controlled from the outside;
A vehicle position information detecting means for detecting three-dimensional position information of each position on the flight trajectory in the aircraft and a three-dimensional direction vector of the flight trajectory at the position;
Observing means for observing a relative change tendency with respect to the position of the data relating to the radio signal received by the flying object;
A condition satisfying position in which a relative change tendency of data observed by the observation means satisfies a preset condition is obtained, and three-dimensional position information and a direction vector at the condition satisfying position are obtained. And position estimation means for substituting this into the plane equation,
The position estimation means obtains the condition satisfying position at three or more locations from the relative change tendency observed from the observation means three times or more in the process of flying the flying object on mutually different flight trajectories, A position estimation system, wherein the position of the object is estimated based on three-dimensional position information at each condition-satisfying position and an equation of three or more planes into which direction vectors are substituted.
2. The position estimation unit sets the position closest to the object as the condition-satisfying position based on a relative change tendency of data observed by the observation unit. Position estimation system.
The observation means observes a relative change tendency of the propagation delay amount as data relating to the radio signal,
The position estimation system according to claim 2, wherein the position estimation means sets the position where the propagation delay amount observed by the observation means is minimum as the condition satisfying position.
The observation means observes a relative change tendency of the reception power of the radio signal as data relating to the radio signal,
The position estimation system according to claim 2, wherein the position estimation means sets the position where the received power observed by the observation means is maximized as the condition satisfying position.
The observation means observes a relative change tendency of the frequency of the radio signal as data relating to the radio signal,
The position estimation means obtains in advance the frequency f 0 of the radio signal transmitted from the object, and sets the position where the frequency observed by the observation means is closest to the frequency f 0 as the condition satisfying position. The position estimation system according to claim 1.
The observation means continues to acquire data relating to the radio signal until the condition satisfying position can be detected,
The position estimation system according to claim 1, wherein the flying object is changed to another flight trajectory and continues to fly after the condition satisfying position can be detected by the observation means.