JP2021009123A - Positioning device - Google Patents

Abstract

To acquire the position of a radio terminal with high accuracy.SOLUTION: An information processing device 20 executes information acquisition processing for acquiring distance measurement values between three respective stationary stations 14-1 to 14-3 and a radio terminal 12 from the radio terminal 12, distance correction processing for correcting at least one of the three distance measurement values, and position determination processing for processing the position of the radio terminal 12 on the basis of the distance measurement value undergoing the distance correction processing. The distance correction processing is processing for changing the radius of at least one circle among three circles and correcting a distance measurement value corresponding to the circle after changing the radius with the position of each stationary station as a center on the basis of a geometric relation of a circle with the distance measurement value as a radius.SELECTED DRAWING: Figure 1

Description

The present invention relates to a positioning device, and more particularly to a positioning device that measures the position of a wireless terminal based on the distance between the wireless terminal and each of a plurality of fixed stations.

Research and development is being carried out on a positioning system that measures the position of wireless terminals. The wireless terminal measures the distance to each fixed station by transmitting and receiving a wireless signal to and from a plurality of fixed stations whose positions are known. The information processing device acquires the distance measurement result from the wireless terminal and obtains the position of the wireless terminal based on the distance from the wireless terminal to each fixed station. Such a positioning system is expected to be applied to confirmation of the whereabouts of people in a building, inventory management in a factory, and the like.

As a positioning system, the following Patent Document 1 describes a system for searching the position of a moving body holding a beacon device. In this system, each of the plurality of mobile terminals receives the beacon signal transmitted from the beacon device and obtains the distance to the beacon device. The mobile search server acquires information indicating the position of each mobile terminal and the distance to the beacon device from each mobile terminal, and obtains the position of the beacon device.

Further, Patent Document 2 describes a wireless tag distance measuring device. The radio tag distance measuring device transmits a distance measurement signal to the radio tag, and receives an arrival signal transmitted from the radio tag accordingly. The wireless tag distance measuring device measures the distance from the wireless tag distance measuring device to the wireless tag based on the time from transmitting the distance measuring signal to receiving the arrival signal. In this document, it is described that the position of the wireless tag is obtained based on the distance measurement result by a plurality of wireless tag distance measuring devices.

Non-Patent Document 1 describes a technique for finding the distance between a node whose position is unknown and each of three reference nodes whose position is known, and finding the position of the measurement target by a three-point positioning method. Has been described. In the three-point positioning method, a circle centered on the position of the reference node and a radius of the distance to the reference node is obtained for each of the three reference nodes, and the intersection of the three circles is obtained as the position of the node to be measured. The method.

Japanese Unexamined Patent Publication No. 2016-218931 JP-A-2009-174971

A Novel Enhance Positioning Trilateration Algorithm Implementation for Medical Implant In-Body Localization, International Journal of Antennas and Propagation, Vol 2013, Article ID 819695

In a system for positioning a wireless terminal, positioning of the wireless terminal is performed using a wireless signal. Therefore, the positioning accuracy may not be sufficient depending on the propagation condition of the radio signal.

An object of the present invention is to obtain the position of a wireless terminal with high accuracy.

In the present invention, the measured distance between each of the first fixed station, the second fixed station and the third fixed station and the wireless terminal is measured by the first fixed station, the second fixed station and the third fixed station. At least one of them, or the information acquisition process acquired from the wireless terminal, the first distance measurement value between the first fixed station and the wireless terminal, and between the second fixed station and the wireless terminal. The distance correction process for correcting at least one of the second distance measurement value and the third distance measurement value between the third fixed station and the wireless terminal, and the first distance to which the distance correction process is performed. A position determination process for obtaining the position of the wireless terminal based on the measured value, the second distance measured value, and the third distance measured value is executed, and the distance correction process determines the position of the first fixed station. A first circle centered on the first distance measurement value as a radius, a second circle centered on the position of the second fixed station and a radius on the second distance measurement value, and a third fixed station The distance corresponding to the circle after changing the radius of at least one of the third circles centered on the position and having the radius of the third distance measurement value based on the geometrical relationship of each circle. The distance correction process is a process of correcting the measured value, and the distance correction process further includes an intersection relationship in which two of the first circle, the second circle, and the third circle intersect at two points, or the first circle. A one-point contact relationship is established in which two of the second circle and the third circle contact at one point, and the remaining one circle is included in one of the other two circles, or the rest. When one circle of the above includes one of the other two circles, the crossing relationship or the one-point contact relationship is maintained, or the two circles having the crossing relationship are described in the above 1 It is characterized by including an inclusion elimination process in which the radius of the included circle is reduced and the radius of the included circle is increased under the condition that a point contact relationship is established.

Desirably, the inclusion elimination process does not maintain either the crossing relationship or the one-point contact relationship, and the one-point contact relationship is not established for the two circles in the crossing relationship. Includes a process of changing the radius of only one of the contained circles or the contained circle.

Further, in the present invention, the distance measurement value between each of the first fixed station, the second fixed station and the third fixed station and the wireless terminal is set to the first fixed station, the second fixed station and the third fixed. Information acquisition processing acquired from at least one of the stations or the wireless terminal, a first distance measurement value between the first fixed station and the wireless terminal, the second fixed station and the wireless terminal The distance correction process for correcting at least one of the second distance measurement value between the three fixed stations and the third distance measurement value between the third fixed station and the wireless terminal, and the first distance correction process. A position determination process for determining the position of the wireless terminal based on the one distance measurement value, the second distance measurement value, and the third distance measurement value is executed, and the distance correction process is performed on the first fixed station. The first circle centered on the position and the radius of the first distance measurement value, the second circle centered on the position of the second fixed station and the radius of the second distance measurement value, and the third fixed At least one radius of the third circle centered on the position of the station and the radius measured at the third distance is changed based on the geometrical relationship of each circle, and corresponds to the circle after the radius is changed. The distance correction process is a process of correcting the distance measurement value to be performed, and the distance correction process further includes an intersection relationship in which two of the first circle, the second circle, and the third circle intersect at two points, or the first. A one-point contact relationship is established in which two of the circle, the second circle, and the third circle contact at one point, and the remaining one circle is at two points on either of the other two circles. When neither intersects nor touches at one point, the distant circle having the longer center distance from the remaining one of the two circles having the crossing relationship or the one-point contact relationship It is characterized by including a process of changing the radius of the far circle and the remaining one circle so as to intersect.

Further, in the present invention, the measured distance between each of the first fixed station, the second fixed station and the third fixed station and the wireless terminal is set to the first fixed station, the second fixed station and the third fixed. Information acquisition processing acquired from at least one of the stations or the wireless terminal, a first distance measurement value between the first fixed station and the wireless terminal, the second fixed station and the wireless terminal The distance correction process for correcting at least one of the second distance measurement value between the three fixed stations and the third distance measurement value between the third fixed station and the wireless terminal, and the first distance correction process. A position determination process for determining the position of the wireless terminal based on the one distance measurement value, the second distance measurement value, and the third distance measurement value is executed, and the distance correction process is performed on the first fixed station. The first circle centered on the position of, the first distance measurement value as the radius, the second circle centered on the position of the second fixed station, and the second distance measurement value as the radius, and the third At least one radius of the third circle centered on the position of the fixed station and having the third distance measurement value as the radius is changed based on the geometrical relationship of each circle, and the radius is changed to a circle. It is a process of correcting the corresponding distance measurement value. In the distance correction process, there are two circles in the first circle, the second circle, and the third circle, one of which includes the other, and the rest. If one circle does not include either of the other two circles and is not included in either of the other two circles, the circle contained in the other two circles. It is characterized in that the inclusion elimination process is first executed to reduce the radius of the circle and increase the radius of the included circle.

Desirably, the distance correction process is repeatedly executed a plurality of times, and each of the distance correction processes performs the radius of the first circle, the second circle, or the third circle in the previously executed distance correction process. When it is increased or decreased, the radius of the first circle, the second circle, or the third circle is not reduced or increased in the distance correction process executed later.

Desirably, the intersection of the first circle and the second circle subjected to the distance correction process, the intersection of the second circle and the third circle subjected to the distance correction process, and the distance correction process are performed. The position of the wireless terminal is obtained based on the positioning triangle having the intersection of the third circle and the first circle as the apex.

Desirably, when there are a plurality of intersections of the first circle and the second circle to which the distance correction process has been performed, one of the plurality of intersections is set as the first vertex and the distance correction process is performed. When there are a plurality of intersections between the second circle and the third circle, one of the plurality of intersections is set as the second apex, and the third circle and the third circle subjected to the distance correction process are used. When there are a plurality of intersections with one circle, the positioning triangle having one of the plurality of intersections as the third vertex is obtained, and when there are a plurality of positioning triangles, the plurality of positioning triangles are obtained. The position of the wireless terminal is obtained based on the triangle in which the total value of the distances between the vertices is the smallest.

Desirably, when there are a plurality of intersections of the first circle and the second circle to which the distance correction process has been performed, one of the plurality of intersections is set as the first apex and the distance correction process is performed. When there are a plurality of intersections between the second circle and the third circle, one of the plurality of intersections is set as the second apex, and the distance correction process is performed on the third circle and the third circle. When there are a plurality of intersections with one circle, the positioning triangle having one of the plurality of intersections as the third apex is obtained, and when there are a plurality of positioning triangles, the plurality of positioning triangles are obtained. The position of the wireless terminal is obtained based on the triangle having the smallest area among the triangles of.

Desirably, the position of the wireless terminal is determined based on the center of gravity of the positioning triangle.

According to the present invention, the position of the wireless terminal can be obtained with high accuracy.

It is a figure which shows the positioning system which concerns on 1st Embodiment. It is a figure explaining the basic process. It is a figure explaining the problem about the basic processing. It is a figure explaining the inclusion elimination process. It is a figure which shows the 1st pattern at the time of executing the limited distance correction processing. It is a figure which shows the 2nd pattern at the time of executing the limited distance correction processing. It is a figure which shows the 3rd pattern at the time of executing the limited distance correction processing. It is a figure which shows the 4th pattern at the time of executing the limited distance correction processing. It is a figure which shows the 5th pattern at the time of executing the limited distance correction processing. It is a figure which shows the 6th pattern at the time of executing the limited distance correction processing. It is a figure which shows the 7th pattern when the limited distance correction processing is executed. It is a figure which shows the 8th pattern at the time of executing the limited distance correction processing. It is a figure which shows the 9th pattern when the limited distance correction processing is executed. It is a figure which shows the tenth pattern in the case of executing the limited distance correction process. It is a figure which shows the example of the hardware of a wireless terminal. It is a figure which shows the example of the hardware of an information processing apparatus. It is a figure which shows the positioning system which concerns on 2nd Embodiment.

(1) Configuration of Positioning System FIG. 1 shows a positioning system 10 according to an embodiment of the present invention. The positioning system 10 includes a wireless terminal 12, fixed stations 14-1 to 14-3, a network wireless device 16, a communication line 18, and an information processing device 20. The wireless terminal 12 transmits and receives radio signals to and from each of the fixed stations 14-1 to 14-3, and measures the distance to each fixed station. The network wireless device 16 performs wireless communication with the wireless terminal 12 and acquires measurement information indicating a measurement result by the wireless terminal 12. The network wireless device 16 transmits the measurement information acquired from the wireless terminal 12 to the information processing device 20 via a communication line 18 such as the Internet. The information processing device 20 as a positioning device corrects each distance measurement value included in the measurement information by a distance correction process described later, and measures the position of the wireless terminal 12 based on each corrected distance measurement value.

(2) Basic processing executed by the positioning system The basic processing executed by the positioning system 10 will be described. The wireless terminal 12 transmits and receives radio signals to and from each of the fixed stations 14-1 to 14-3, measures the distance to each fixed station, and acquires each distance measurement value. Wireless terminal 12 generates the measurement information including the distance measurement _r 1 ~r _3. However, the distance measurement values r _{1 to} r ₃ are measurement values of the distance from the wireless terminal 12 to the fixed stations 14-1 to 14-3, respectively. The wireless terminal 12 performs wireless communication with the network wireless device 16 and transmits measurement information to the network wireless device 16. The network wireless device 16 receives the measurement information and transmits it to the information processing device 20 via the communication line 18. The information processing device 20 receives measurement information from the network wireless device 16 via the communication line 18.

The information processing apparatus 20 obtains the distance measurement value _r 1 ~r ₃ from the measurement information, performs distance correction processing with respect to the distance measure _r 1 ~r _3. The distance correction process is a process of sequentially executing corrections for two distance measurement values out of the _three distance measurement values r _{1 to} r ₃ for three types of combinations in which two are selected from the three distance measurement values. The two distance measurement values corrected earlier are used for the correction of the next and subsequent distance measurement values. The distance correction process may be repeatedly executed over a plurality of times.

The information processing device 20 stores the positions of the fixed stations 14-1 to 14-3 in advance. The information processing device 20 obtains the position of the wireless terminal 12 by using the distance measurement values r ₁ , r ₂ and r ₃ that have been subjected to the distance correction process. That is, the position of the fixed station 14-1 is the center P ₁ , the circle C ₁ having the distance measurement value r ₁ as the radius, and the position of the fixed station 14-2 is the center P ₂ , and the distance measurement value r ₂ is the radius. a circle _{C 2} that obtains the center _{P 3} the position of the fixed station 14-3, the distance measurement value _{r 3} of the intersection between the circle _{C 3} whose radius as a position of the wireless terminal 12.

A specific example of the basic processing will be described with reference to FIG. In FIG. 2 (a), the fixed station position _P 1 to P ₃ is the position of the fixed station 14-1 to 14-3, the distance correction process range measurements _r 1 ~r ₃ before is performed schematic Is shown. Circle _C 1 -C _3, respectively, around the fixed station position P1～P _3, a circle whose radius is the respective distance measurement values _r 1 ~r _3. In the example shown in this figure, circles C _{1 ~} circle C ₃ is not cross each other, further, not also contact at one point with each other, in any of the measured distance value r ₁ ~r ₃ Also includes errors.

In the distance correction process, the circles C _i and C _j intersect at two points or come into contact with two distance measured values r _i and r _j out of the _three distance measured values r _{1 to} r _3. The distance measurement values r _i and r _j are corrected as described above. For example, such processing is performed on a pair of distance measurements r ₁ and r _2, a pair of distance measurements r ₂ and r ₃ , and further distance measurements r ₃ and r _1. Execute for the set of. In this example, the distance measurements r _{1 to} r ₃ are corrected to be greater than the initial values. In FIG. 2 (b), the distance correction processing distance measurement r ₁ ~r ₃ after being performed is shown schematically. In the example shown in this figure, circles C ₁ to C ₃ intersect each other, and the position in the area P surrounded by the circumference of circles C ₁ to C ₃ is defined as the position of the wireless terminal 12. Desired.

In the basic process, even if the distance correction process is repeatedly executed, the first circle C ₁ to the third circle C ₃ may not intersect each other or come into contact with each other at one point. In the following description, it is said that the two circles are in contact with each other, including the state where the two circles are in contact with each other at one point and the state where the two circles are in contact with each other at two points.

For example, as shown in FIG. 3 (a), the first circle C ₁ includes the third circle C ₃ , and the second circle C ₂ is the first circle C ₁ and the third circle C ₃ . A case will be described in which the case is not included in any of the above and does not come into contact with the first circle C ₁ and the third circle C ₃ . As shown in FIG. 3 (b), when crossing the first circle C ₁ and the second circular C ₂ to increase the respective radii of the first circular C ₁ and the second circular C _2, the first the distance between the circumference and the circumference of the third circular C ₃ circles C ₁ becomes longer.

Next, as shown in FIG. 3 (c), the first circle radius of C ₁ can be reduced, by increasing the radius of the third circular C _3, first circular C ₁ and third circular C ₃ When they are brought into contact with each other at one point, the circumference of the first circle C _{1 and} the circumference of the second circle C ₂ are separated, and the first circle C ₁ and the second circle C ₂ do not intersect. In this state, the radius of each of the first circle C ₁ and the second circle C ₂ is increased in the same manner as in the process of changing from the state of FIG. 3 (a) to the state of FIG. _{When the 1} and the 2nd circle C ₂ are crossed, the circumference of the 1st circle C _{1 and} the circumference of the 3rd circle C ₃ are separated again. In this way, the process of contacting the first circle C ₁ and the second circular C ₂ to increase the respective radii of the first circular C ₁ and the second circular C _2, the first circle radius of C ₁ small , even when repeatedly executes contacting the first circle C ₁ and the third circular C ₃ by increasing the radius of the third circular C _3, first circular C _{1 ~} third circular C ₃ are in contact with each other It does not converge to the state, and it becomes difficult to obtain the position of the wireless terminal 12. The limited distance correction process shown below avoids such a non-convergent state.

The limited distance correction process changes the radius of at least one of these three circles according to the restrictions (rules) imposed according to the geometrical relationship of the first circle C ₁ to the third circle C _3. , It is a process of correcting the distance measurement value corresponding to the circle after changing the radius.

(3) Restricted distance correction process (3-1) Rules applied in the restricted distance correction process The restricted distance correction process is executed according to the following rules 1 to 6. Rules 1 to 5 assume that the radii of both of the two circles are changed.

(I) Rule 1
If there are two circles in the first circle C ₁ to the third circle C ₃ that have an intensional relationship, and the remaining one circle does not have an intensional relationship with the other two circles, the intensional relationship is canceled. The distance adjustment process is executed first. Here, the intensional relationship refers to the relationship between two circles in which one of the two circles includes the other. The inclusion relationship referred to in the specification of the present application does not include a state in which the other circle inside one circle contacts one circle at one point.

(Ii) Rule 2
For a circle whose radius has been increased by the distance adjustment process executed earlier, the radius is not decreased by the distance adjustment process executed later. Similarly, for a circle whose radius has been reduced by the distance adjustment process executed earlier, the radius is not increased by the distance adjustment process executed later.

(Iii) Rule 3
For the two circles having an intensional relationship, the distance adjustment process for eliminating the intensional relationship is performed by reducing the radius of the circle on the inclusive side and increasing the radius of the circle on the inclusive side.

(Iv) Rule 4
When there are two circles in contact in the first circle C ₁ to the third circle C ₃ , and the remaining one circle does not contact any of the other two, the remaining one circle and the other two circles. Execute the distance adjustment process with one of the circles. This distance adjustment process is executed so that the crossing relationship or the one-point contact relationship of the other two circles is maintained, or the one-point contact relationship is established for the two circles that are in the crossing relationship.

(V) Rule 5
When one circle (circle A) of the first circle C ₁ to the third circle C ₃ does not make contact with any of the other two (circle B and circle C), the circle B and the circle C , The distance adjustment process is executed between the one having the longer center distance from the circle A and the circle A.

(Iv) Rule 6
If the radii of both of the two circles cannot be changed due to the restrictions stipulated in Rules 1 to 5, the process of changing the radii of the remaining one circle is executed.

(3-2) Element processing The element processing executed in the limited distance correction processing will be described. Element processing includes inclusion elimination processing and approach processing. The inclusion elimination process is a process of eliminating the inclusion relationship of two circles having an inclusion relationship, and is performed according to rule 3. In the inclusion elimination process, as a general rule, the radius of the circle on the inclusion side is reduced and the radius of the circle on the inclusion side is increased. The approach process is a process of increasing the radius of two circles that are not inclusive and are not in contact with each other and bring these two circles into contact with each other.

Here, bringing the two circles into contact includes not only contacting the two circles at one point but also crossing the two circles at two points. Further, the state in which the two circles are in contact includes a state in which the two circles are in contact at one point and a state in which the two circles intersect at two points.

In the approach process, in principle, the radii of both of the two circles are increased. In the limited distance correction process, the inclusion elimination process or the approach process is executed for the two circles selected from the first circle C ₁ to the third circle C ₃ according to the above rule.

(3-2-1) Encapsulation elimination processing The inclusion elimination processing will be described. FIG. 4A shows a circle C _i and a circle C _j including the circle C _i . The distance between the center of the circle C _i and the circle C _j is _{di j} . In encapsulated resolving process, for contacting the circle _{C i} and the circle _{C j} at one point, the radius _{r j} of radius _{r i} and the circle _{C j} circle _{C i,} respectively, the correction according to equation (1) and (Equation 2) Will be done.

(Number _{1) r i ← (r i} + r j -d ij) / 2 + δ i
(Number _{2) r j ← (r i} + r j + d ij) / 2-δ j

However, the symbol "←" means that the value on the left side is updated by the formula on the right side. The margins δ _i and δ _j are positive values for bringing the circles C _i and the circle C _j into contact with each other with a margin. The margins δ _i and δ _j may be 0.

(Equation 1) is derived by geometric analysis with reference to FIG. 4 (b). FIG. 4B shows the relationship between the circle C _i and the circle C _j before correction. The corrected circles C _i and C _j come into contact with each other at the midpoint of the perimeter line segment A that connects the circumference of the circle C _i before correction and the circumference of the circle C _j before correction at the shortest. The increase in the radius of the circle C _{i in} the correction and the decrease in the radius of the circle C _{j in} the correction are both half the length L of the circumferential line segment A. The length L of the circumferential line segment A is represented by (Equation 3).

(Number _{3) L = r j - (} d ij + r i)

Therefore, the radii R _i and R _j of the corrected circles C _i and C _j are represented by (Equation 4) and (Equation 5), respectively.

(Number _{4) R i = r i +} L / 2 = r i + [r j - (d ij + r i)] / 2
= (R _i + r _j − _dij ) / 2
(Equation 5) R _j = r _j −L / 2 = r _j − [r _j − (d _ij + r _i )] / 2
= (R _i + r _j + _dij ) / 2

In (Equation 1) and (Equation 2), (Equation 4) and (Equation 5) are applied as the equations on the right side, respectively, the margin δ _i is added, and the margin δ _j is subtracted, respectively. FIG. 4C shows the corrected circles C _i and C _j .

(3-2-2) Approach processing Next, the approach processing will be described. The approach process is executed when the circles C _i and C _j are not inclusive and are not in contact with each other, that is, when the circles C _i and C _j are separated from each other.

Radius _{R i} of the circle _{C i} after correction, and is a multiple of the radius _{r i} of the pre-correction circle _{C i,} the radius _{R j} of the circle _{C j} after correction, the radius r of the pre-correction circle _{C j} in case of the an a multiple of _j, conditions when the circle C _i and the circle C _j corrected is in contact at one point can be expressed by equation (6).

(Number _{6) a · (r i +} r j) = d ij

Therefore, the magnification a is obtained as in (Equation 7).
(Number _{7) a = d ij / (} r i + r j)

In approaching process, for contacting the circle _{C i} and the circle _{C j} at one point, the radius _{r j} of radius _{r i} and the circle _{C j} circle _{C i,} respectively, in accordance with the following equation (8) and (9) It will be corrected.

(Number _{8) r i ← a · r} i + δ i = r i · d ij / (r i + r j) + δ i
(Number _{9) r j ← a · r} j + δ j = r j · d ij / (r i + r j) + δ j

(3-2-3) Contact maintenance process Both the inclusion elimination process and the approach process are processes executed for two circles. When two of the three circles come into contact with each other, the contact maintenance process is executed when the inclusion elimination process or the approach process is executed for one of the two circles and the remaining one circle. The contact maintenance process is a process of maintaining the contact state of the two circles that were in contact with each other when the inclusion removal process or the approach process is executed for one of the two circles in contact with the remaining one circle. And it is done according to rule 4.

That is, in the contact maintenance process, the crossing relationship or the one-point contact relationship is maintained for the two circles having the crossing relationship or the one-point contact relationship, or the one-point contact relationship is established for the two circles having the crossing relationship. Under the contact maintenance condition, the radii of the two circles to be processed are corrected.

Specifically, the inclusion cancellation processing, when the radius r _j of radius r _i and the circle C _j circle C _i is, respectively, were to be corrected by the equation (1) and (Equation 2), the contact of the If the maintenance condition is not satisfied, it is one of the radius of the circle C _i and the circle C _j is constant, only the other is corrected. That is, when the radius of the circle C _i is made constant and the radius of the circle C _j is corrected in the process similar to the inclusion elimination process, the radius of the circle C _j is reduced and the radius of the circle C _i is maintained as it is. The radius of the circle C _j is contained until the relationship is eliminated, reducing a predetermined step size. Further, when the radius of the circle C _j is made constant and the radius of the circle C _i is corrected in the process similar to the inclusion elimination process, the radius of the circle C _i is increased and the radius of the circle C _j is maintained as it is. The radius of the circle C _i is contained until the relationship is eliminated, increasing by a predetermined step size.

Similarly, in the proximity process, the radius of the radius r _i and the circle C _j circle C _i is, when respectively, are corrected by the equation (8) and (9), above the contact maintaining condition is satisfied If the resulting not is one of constant radius of the circle C _i and the circle C _j, only the other is corrected. That is, when the radius of the circle C _i is made constant and the radius of the circle C _j is corrected in the process similar to the approach process, the radius of the circle C _j is increased and the radius of the circle C _i is maintained as it is. The radius of the circle C _j is to the circle C _i and the circle C _j are in contact, increasing by a predetermined step size. Further, when the radius of the circle C _j is made constant and the radius of the circle C _i is corrected in the process similar to the approach process, the radius of the circle C _i is increased and the radius of the circle C _j is maintained as it is. The radius of the circle C _i until the circle C _i and the circle C _j are in contact, increasing by a predetermined step size.

In the above, when the contact maintenance condition is not maintained, the radius of the circle C _j is corrected and the radius of the circle C _i is maintained as it is, or the radius of the circle C _i is corrected and the radius of the circle C _j is adjusted. The process of maintaining it as it is was explained. As long as the contact maintenance conditions are satisfied, the radii of both the circle C _i and the circle C _j may be corrected, or one radius may be kept constant and the other radius may be corrected.

(4) Example of Limited Distance Correction Processing An example of the limited distance correction processing will be described with reference to FIGS. 5 to 14. In the limited distance correction process, the information processing apparatus 20 appropriately executes the inclusion elimination process and the approach process as described in (3-2-1) and (3-2-2) above. In the inclusion elimination process, if the contact maintenance conditions are not satisfied by the processes according to (Equation 1) and (Equation 2), the information processing apparatus 20 performs the contact maintenance process as described in (3-2-3) above. To execute. In the approach processing, when the contact maintenance condition is not satisfied by the processing according to (Equation 8) and (Equation 9), the information processing apparatus 20 performs the contact maintenance processing as described in (3-2-3) above. Execute. In the following description of the first to tenth patterns, a process similar to the inclusion elimination process (encapsulation elimination process extended so that the radius of either of the two circles is constant) and an inclusion elimination process are described. Is also called inclusion elimination processing. Similarly, a process similar to the approach process (an approach process extended so that the radius of one of the two circles is constant) and an approach process are collectively referred to as an approach process.

(4-1) First pattern In FIGS. 5 (a) to 5 (c), the first pattern in the case of executing the limited distance correction process for the first circle C ₁ to the third circle C ₃ is shown. The pattern is shown. As shown in FIG. 5A, the first circle C ₁ to the third circle C ₃ are not in contact with each other. The information processing device 20 executes an approach process to the first circle C ₁ and the second circle C ₂ . FIG. 5B shows that the first circle C ₁ and the second circle C ₂ are in contact with each other at one point due to the approach process.

As shown in FIG. 5 (b), the center distance of the first circle C ₁ from the third circle C ₃ is longer than that of the second circle C ₂ . Therefore, the information processing apparatus 20 executes the approach process to the first circle C ₁ and the third circle C ₃ according to the rule 5. FIG. 5C shows that the first circle C ₁ to the third circle C ₃ are in contact with each other due to the approach processing. FIG. 5 (c) shows the intersection of the first circle C ₁ and the second circle C ₂ , the intersection of the second circle C ₂ and the third circle C ₃ , and the intersection of the third circle C ₃ and the first circle C ₁ . The region Q of the triangle for positioning (hereinafter, simply referred to as a triangle) having the apex is shown. The information processing device 20 obtains the position of the wireless terminal 12 based on the range occupied by the area Q.

The process of determining the position of the wireless terminal 12 by the information processing device 20 based on the range occupied by the triangular region may be the process of determining the center of gravity of the triangle as the position of the wireless terminal 12.

In the information processing device 20, when there are a plurality of intersections between the first circle C ₁ and the second circle C ₂ , one of the plurality of intersections is set as the first vertex, and the second circle C ₂ and the second circle C ₂ and the _second . When there are multiple intersections with the 3 circle C ₃ , one of the multiple intersections is set as the second vertex, and when there are multiple intersections between the 3rd circle C ₃ and the 1st circle C ₁ , there are multiple intersections. Find a triangular region with one of the intersections of the above as the third vertex.

The information processing device 20 determines the position of the wireless terminal 12 based on the total value of the distances between the vertices among the plurality of triangles thus obtained, that is, the range occupied by the area of the triangle having the minimum outer peripheral length. Ask for. Further, the information processing device 20 may determine the position of the wireless terminal 12 based on the range occupied by the area of the triangle having the smallest area among the plurality of triangles. The process of determining the position of the wireless terminal 12 by the information processing device 20 based on the range occupied by the triangular region may be the process of determining the center of gravity of the triangle as the position of the wireless terminal 12.

(4-2) Second pattern In FIGS. 6 (a) to 6 (c), there is a second pattern in which the limited distance correction process is executed for the first circle C ₁ to the third circle C ₃ . The pattern is shown. As shown in FIG. 6A, the first circle C ₁ and the second circle C ₂ intersect at two points, and the remaining one circle, the third circle C _3, is the first circle. It does not come into contact with either C ₁ or the second circle C ₂ . Further, the center distance of the first circle C ₁ is longer than that of the second circle C ₂ from the third circle C ₃ . Therefore, the information processing apparatus 20 executes the approach process to the first circle C ₁ and the third circle C _{3 in} accordance with the rules 4 and 5. In FIG. 6 (b), the closer the process, the first circular C ₁ and third circular C ₃ has been shown to have a state of contact at one point.

In the state shown in FIG. 6B, the second circle C ₂ and the third circle C ₃ are not in contact with each other. Therefore, the information processing device 20 executes the approach process to the second circle C ₂ and the third circle C ₃ . FIG. 6C shows that the first circle C ₁ to the third circle C ₃ are in contact with each other due to the approach process. In the example shown in FIG. 6C, the first circle C ₁ to the third circle C ₃ intersect at one point α. The information processing device 20 obtains the point α as the position of the wireless terminal 12.

The first circle C ₁ to the third circle C ₃ do not intersect at one point α, and as shown in FIG. 5 (c), the intersection of the first circle C ₁ and the second circle C ₂ , the second When the intersection of the circle C ₂ and the third circle C _{3 and} the intersection of the third circle C ₃ and the first circle C ₁ occur, the information processing apparatus 20 executes the same processing as in the first pattern. That is, the information processing device 20 obtains the position of the wireless terminal 12 based on the range occupied by the triangular region having these three intersections as vertices. The process of determining the position of the wireless terminal 12 by the information processing device 20 based on the range occupied by the triangular region may be the process of determining the center of gravity of the triangle as the position of the wireless terminal 12.

Further, in the information processing apparatus 20, when there are a plurality of intersections of the first circle C ₁ and the second circle C ₂ , one of the plurality of intersections is set as the first vertex, and the second circle C ₂ and the second circle C ₂ and the _second . When there are multiple intersections with the 3 circle C ₃ , one of the multiple intersections is set as the second vertex, and when there are multiple intersections between the 3rd circle C ₃ and the 1st circle C ₁ , there are multiple intersections. Find a triangular region with one of the intersections of the above as the third vertex.

The information processing device 20 determines the position of the wireless terminal 12 based on the total value of the distances between the vertices among the plurality of triangles thus obtained, that is, the range occupied by the area of the triangle having the minimum outer peripheral length. Ask for. Further, the information processing device 20 may determine the position of the wireless terminal 12 based on the range occupied by the area of the triangle having the smallest area among the plurality of triangles. The process of determining the position of the wireless terminal 12 by the information processing device 20 based on the range occupied by the triangular region may be the process of determining the center of gravity of the triangle as the position of the wireless terminal 12.

(4-3) Third pattern In FIGS. 7 (a) to 7 (c), there is a third pattern in which the limited distance correction process is executed for the first circle C ₁ to the third circle C ₃ . The pattern is shown. As shown in FIG. 7 (a), the first circular _{C 1} are encompassed second circular _{C 2,} a second circular _{C 2} third circular _{C 3} intersect at two points. The information processing device 20 executes the inclusion elimination process for the first circle C ₁ and the second circle C _{2 in} accordance with rule 1. FIG. 7B shows that the inclusion elimination process brought the first circle C ₁ and the second circle C ₂ into contact at two points. In a state in which is being shown in FIG. 7 (b), the first circular C ₁ and third circular C ₃ is not in contact. Therefore, the information processing device 20 executes the approach process to the first circle C ₁ and the third circle C ₃ . In FIG. 7 (c), the first circle C ₁ and the third circle C ₃ are brought into contact with each other because the first circle C ₁ and the third circle C ₃ are brought into contact with each other. It is shown that

The information processing device 20 performs the same processing as the processing described for the first pattern and the second pattern to perform the intersection of the first circle C ₁ and the second circle C ₂ , the second circle C ₂ and the third circle C ₃ Based on the intersection of the third circle C ₃ and the first circle C ₁ , one triangle for finding the position of the wireless terminal 12 is obtained. The information processing device 20 determines the position of the wireless terminal 12 based on the range occupied by the triangular area.

As shown in FIG. 7 (c), there are _two intersections of the first circle C ₁ and the second circle C ₂ , the intersection β ₁ and the intersection β ₂ . There are two intersections of the second circle C ₂ and the third circle C ₃ , the intersection β ₃ and the intersection β ₄ . The intersection of the third circle C ₃ and the first circle C ₁ is only the intersection β ₅ . The information processing apparatus 20 is a distance between the vertices of the intersection of _one of the intersection β ₁ and the intersection β ₂ , the intersection of one of the intersection β ₃ and the intersection β ₄ , and the triangle having the intersection β ₅ as the apex. The position of the wireless terminal 12 is obtained based on the range occupied by the triangular area where the total value of is the smallest. That is, the center of gravity of the triangle having the smallest total value of the distances between the vertices is obtained as the position of the wireless terminal 12. The information processing device 20 has the smallest area of the intersection of _one of the intersection β ₁ and the intersection β ₂ , the intersection of one of the intersection β ₃ and the intersection β ₄ , and the triangle having the intersection β ₅ as the apex. The position of the wireless terminal 12 may be obtained based on the range occupied by a certain triangular area. That is, the center of gravity of the triangle having the smallest area may be obtained as the position of the wireless terminal 12.

(4-4) Fourth pattern In FIGS. 8 (a) to 8 (c), there is a fourth pattern in which the limited distance correction process is executed for the first circle C ₁ to the third circle C ₃ . The pattern is shown. As shown in FIG. 8 (a), the first circle C ₁ is included in the second circle C ₂ . Third circular _{C 3} is any first circle _{C 1} and the second circular _{C 2} even without inclusion not encompassed in any of the first circular _{C 1} and the second circular _{C 2.} Further, the third circle C ₃ is not in contact with either the first circle C ₁ or the second circle C ₂ . The information processing device 20 executes the inclusion elimination process for the first circle C ₁ and the second circle C _{2 in} accordance with rule 1. FIG. 8B shows that the first circle C ₁ and the second circle C ₂ are in contact with each other at one point due to the inclusion elimination process.

As shown in FIG. 8 (b), the third circle C ₃ is not inclusive with any of the first circle C ₁ and the second circle C ₂ . Further, the third circle C ₃ is not in contact with either the first circle C ₁ or the second circle C ₂ . The information processing apparatus 20 in accordance with Rule 5, among the first circle _{C 1} and the second circular _{C 2,} the center distance is longer first circle _{C 1} between the third circular _{C 3,} the third circular _{C 3} On the other hand, the approach process is executed.

FIG. 8C shows that the first circle C ₁ to the third circle C ₃ are in contact with each other due to the approach process. The information processing apparatus 20 performs the same processing as the processing described for the first pattern to the third pattern, at the intersection of the first circle C ₁ and the second circle C ₂ , and the second circle C ₂ and the third circle C ₃ Based on the intersection of the third circle C ₃ and the first circle C ₁ , one triangle for finding the position of the wireless terminal 12 is obtained. The information processing device 20 determines the position of the wireless terminal 12 based on the range occupied by the triangular area.

(4-5) Fifth Pattern In FIGS. 9 (a) to 9 (c), a fifth pattern is shown in the case where the limited distance correction process is executed for the first circle C ₁ to the third circle C ₃ . The pattern is shown. As shown in FIG. 9A, the first circle C ₁ and the second circle C ₂ intersect at two points. Further, the third circle C ₃ includes the first circle C ₁ and the second circle C ₂ .

The information processing apparatus 20 in accordance with Rule 5, among the first circle _{C 1} and the second circular _{C 2,} the center distance is longer second circle _{C 2} between the third circular _{C 3,} the third circular _{C 3} On the other hand, the inclusion elimination process is executed. FIG. 9B shows that the second circle C ₂ and the third circle C ₃ are in contact with each other at one point due to the inclusion elimination process.

In a state in which is being shown in FIG. 9 (b), the first circular C ₁ and third circular C ₃ is not in contact. Therefore, the information processing device 20 executes the approach process to the first circle C ₁ and the third circle C ₃ . The information processing apparatus 20, after the radius of the third circular C ₃ is constant, may be increased only first circle radius of C _1. As a result, while the one-point contact relationship between the second circle C ₂ and the third circle C ₃ is maintained, as shown in FIG. 9 (c), the first circle C ₁ to the third circle C ₃ are formed. It will be in contact with each other.

The information processing apparatus 20 performs the same processing as the processing described for the first pattern to the third pattern, at the intersection of the first circle C ₁ and the second circle C ₂ , and the second circle C ₂ and the third circle C ₃ Based on the intersection of the third circle C ₃ and the first circle C ₁ , one triangle for finding the position of the wireless terminal 12 is obtained. The information processing device 20 determines the position of the wireless terminal 12 based on the range occupied by the triangular area.

(4-6) Sixth Pattern In FIGS. 10 (a) to 10 (c), the sixth pattern in the case of executing the limited distance correction processing for the first circle C ₁ to the third circle C ₃ is shown. The pattern is shown. As shown in FIG. 10 (a), the first circular _{C 1} are encompassed second circular _{C 2,} the second circular _{C 2} is included in the third circular _{C 3.} The information processing device 20 executes the inclusion elimination process for the first circle C ₁ and the second circle C ₂ . FIG. 10B shows that the inclusion elimination process brought the first circle C ₁ and the second circle C ₂ into contact with each other at one point.

By the inclusion elimination process for the first circle C ₁ and the second circle C ₂ , the radius of the first circle C ₁ is increased and the radius of the second circle C ₂ is decreased. Accordingly, in the next process, to reduce the first circle radius of C _1, it is not allowed by the rule 2 to increase the second circle radius C _2. Therefore, the information processing apparatus 20 executes the inclusion elimination process for the first circle C ₁ and the third circle C ₃ . Although the first circle C ₁ and the third circle C ₃ come into contact with each other by this inclusion elimination process, the inclusion relationship between the second circle C ₂ and the third circle C ₃ is not eliminated. Therefore, the information processing apparatus 20 in accordance with rule 6, to reduce the radius only third circular C _3.

In FIG. 10 (c), the first circle C ₁ and the third circle C ₃ intersect at two points, and the first circle C ₁ and the second circle C ₂ intersect at two points by the above processing. It is shown that the 1st circle C ₁ to the 3rd circle C ₃ are in contact with each other. The information processing apparatus 20 performs the same processing as the processing described for the first pattern to the third pattern, at the intersection of the first circle C ₁ and the second circle C ₂ , and the second circle C ₂ and the third circle C ₃ Based on the intersection of the third circle C ₃ and the first circle C ₁ , one triangle for finding the position of the wireless terminal 12 is obtained. The information processing device 20 determines the position of the wireless terminal 12 based on the range occupied by the triangular area.

(4-7) Seventh Pattern In FIGS. 11 (a) to 11 (c), the seventh pattern in the case of executing the limited distance correction processing for the first circle C ₁ to the third circle C ₃ is shown. The pattern is shown. As shown in FIG. 11 (a), the first circular _{C 1} are encompassed second circular _{C 2} and third circular _{C 3,} second circular _{C 2} and third circular _{C 3} is crossed at two points doing. The information processing device 20 executes the inclusion elimination process for the first circle C ₁ and the second circle C ₂ . FIG. 11B shows that the inclusion elimination process brought the first circle C ₁ and the second circle C ₂ into contact with each other at one point.

In the state 11 shown (b), the first circular C ₁ and third circular C ₃ is not in contact. Therefore, the information processing apparatus 20 executes the inclusion elimination process for the first circle C ₁ and the third circle C ₃ .

FIG. 11 (c) shows a state in which the first circle C ₁ to the third circle C ₃ come into contact with each other by the inclusion elimination process. The information processing apparatus 20 performs the same processing as the processing described for the first pattern to the third pattern, at the intersection of the first circle C ₁ and the second circle C ₂ , and the second circle C ₂ and the third circle C ₃ Based on the intersection of the third circle C ₃ and the first circle C ₁ , one triangle for finding the position of the wireless terminal 12 is obtained. The information processing device 20 determines the position of the wireless terminal 12 based on the range occupied by the triangular area.

(4-8) Eighth pattern In FIGS. 12 (a) and 12 (b), the eighth pattern in the case of executing the limited distance correction process for the first circle C ₁ to the third circle C ₃ is shown. The pattern is shown. As shown in FIG. 12 (a), the first circle C ₁ and the second circle C ₂ intersect at two points. Further, the third circle C ₃ is included in the first circle C ₁ .

The information processing device 20 executes the inclusion elimination process for the first circle C ₁ and the third circle C ₃ according to the rule 1. In FIG. 12B, the inclusion elimination process brings the first circle C ₁ and the third circle C ₃ into contact with each other at one point, and the first circle C ₁ and the second circle C ₂ come into contact with each other at two points. It is shown that the intersecting state is maintained. Further, FIG. 12B shows that the first circle C ₁ to the third circle C ₃ are in contact with each other. The information processing apparatus 20 performs the same processing as the processing described for the first pattern to the third pattern, at the intersection of the first circle C ₁ and the second circle C ₂ , and the second circle C ₂ and the third circle C ₃ Based on the intersection of the third circle C ₃ and the first circle C ₁ , one triangle for finding the position of the wireless terminal 12 is obtained. The information processing device 20 determines the position of the wireless terminal 12 based on the range occupied by the triangular area.

(4-9) Ninth Pattern In FIGS. 13 (a) and 13 (b), a ninth pattern is shown in the case where the limited distance correction process is executed for the first circle C ₁ to the third circle C ₃ . The pattern is shown. As shown in FIG. 13 (a), the first circle C ₁ and the third circle C ₃ intersect at two points, and the second circle C ₂ and the third circle C ₃ also intersect at two points. There is. The first circle C ₁ and the second circle C ₂ are not in contact with each other and are not inclusive.

The information processing device 20 executes an approach process to the first circle C ₁ and the second circle C ₂ . FIG. 13B shows that the first circle C ₁ to the third circle C ₃ are in contact with each other due to the approach processing. The information processing apparatus 20 performs the same processing as the processing described for the first pattern to the third pattern, at the intersection of the first circle C ₁ and the second circle C ₂ , and the second circle C ₂ and the third circle C ₃ Based on the intersection of the third circle C ₃ and the first circle C ₁ , one triangle for finding the position of the wireless terminal 12 is obtained. The information processing device 20 determines the position of the wireless terminal 12 based on the range occupied by the triangular area.

(4-10) Tenth pattern In FIGS. 14 (a) to 14 (c), the tenth pattern in the case of executing the limited distance correction processing for the first circle C ₁ to the third circle C ₃ is shown. The pattern is shown. As shown in FIG. 14 (a), the first circle C ₁ and the second circle C ₂ are not in contact with each other and are not inclusive. Further, first circular _{C 1} and the second circular _{C 2} are both included in the third circular _{C 3,} the direction of the second circular _{C 2} between the third circular _{C 3} as compared with the first circular _{C 1} The center distance of is long. Therefore, the information processing device 20 executes the inclusion elimination process for the second circle C ₂ and the third circle C ₃ .

FIG. 14B shows that the second circle C ₂ and the third circle C ₃ are in contact with each other at one point due to the inclusion elimination process. In the state shown in FIG. 14B, the first circle C ₁ is included in the third circle C ₃ . Therefore, the information processing apparatus 20 executes the inclusion elimination process for the first circle C ₁ and the third circle C ₃ .

FIG. 14 (c), by inclusion resolving process for the first circle C ₁ and the third circular C _3, first circular C _{1 ~} third circular C ₃ is indicated that a state of contact with each other There is. The information processing apparatus 20 performs the same processing as the processing described for the first pattern to the third pattern, at the intersection of the first circle C ₁ and the second circle C ₂ , and the second circle C ₂ and the third circle C ₃ Based on the intersection of the third circle C ₃ and the first circle C ₁ , one triangle for finding the position of the wireless terminal 12 is obtained. The information processing device 20 determines the position of the wireless terminal 12 based on the range occupied by the triangular area.

(5) Hardware Example FIG. 15 shows an example of the hardware of the wireless terminal 12. The wireless terminal 12 includes a wireless unit 32 and an information processing unit 34. The wireless unit 32 wirelessly transmits the information acquired from the information processing unit 34 to the fixed stations 14-1 to 14-3 or the network wireless device 16. Further, the radio signal transmitted from the fixed stations 14-1 to 14-3 or the network wireless device 16 is received, and the information included in the wireless signal is output to the information processing unit 34.

The information processing unit 34 includes a distance measuring unit 36 and a measurement information generating unit 38. The information processing unit 34 may include a processor that executes a program. In this case, the information processing unit 34 internally configures the distance measurement unit 36 and the measurement information generation unit 38 by executing the program.

The distance measurement unit 36 transmits and receives radio signals to and from the fixed stations 14-1 to 14-3 via the radio unit 32, and obtains distance measurement values r _{1 to} r ₃ to each fixed station. Measurement information generation unit 38 generates measurement information including the distance measurement value r ₁ ~r _3, and wirelessly transmits the measurement information to the network the wireless device 16 via the radio unit 32.

FIG. 16 shows an example of the hardware of the information processing apparatus 20. The information processing device 20 includes an interface 50 and an information processing unit 52. The information processing device 20 may be a computer that functions as a server. The interface 50 connects the information processing unit 52 to the communication line 18. The information processing unit 52 includes an information acquisition unit 54, a distance correction unit 56, and a position determination unit 58. The information processing unit 52 may include a processor that executes a program. In this case, the information processing unit 52 internally configures each component (information acquisition unit 54, distance correction unit 56, and position determination unit 58) by executing the program.

The information acquisition unit 54 receives the measurement information from the communication line 18 via the interface 50, and acquires the distance measurement values r _{1 to} r ₃ obtained for each fixed station from the measurement information. Distance correcting unit 56, with respect to three distance measurements _r 1 ~r _3, to perform limited distance correction. The position determination unit 58 obtains the position of the wireless terminal 12 based on the _three distance measurement values r _{1 to} r 3 after the limited distance correction process is executed.

(6) Other Embodiments FIG. 17 shows the positioning system 100 according to the second embodiment. In the positioning system 100, fixed stations 14-1 to 14-3 are connected to the communication line 18. Each of the fixed stations 14-1 to 14-3 acquires the distance measurement values r _{1 to} r ₃ , respectively, by wireless communication with the wireless terminal 12. Fixed station 14-1 to 14-3, the information processing apparatus 20 via the communication line 18, respectively, and transmits the distance measurement value _r 1 ~r _3. Further, at least one of the fixed stations 14-1 to 14-3, the communication between the wireless communication and other fixed station between the radio terminal 12, the distance measurement value _r 1 ~r ₃ together acquired You may. Of the fixed stations 14-1 to 14-3, the fixed station acquired distance measurement _r 1 ~r ₃ together may transmit the distance measurement value _r 1 ~r ₃ to the information processing apparatus 20 via the communication line 18 To do. Information acquisition unit 54 shown in FIG. 16, through the interface 50, to obtain the distance measurement value _r 1 ~r ₃ from at least one of the three fixed stations 14-1 to 14-3.

The positioning system may be provided with four or more fixed stations. In this case, the position of the wireless terminal 12 is measured using three fixed stations selected from four or more fixed stations.

10,100 Positioning system, 12 wireless terminals, 14-1 to 14-3 fixed stations, 16 network wireless devices, 18 communication lines, 20 information processing devices, 32 wireless units, 34, 52 information processing units, 36 distance measurement units, 38 measurement information generation unit, 50 interface, 54 information acquisition unit, 56 distance correction unit, 58 position determination unit.

Claims (9)

The distance measurement value between each of the first fixed station, the second fixed station and the third fixed station and the wireless terminal is set to at least one of the first fixed station, the second fixed station and the third fixed station. Or, the information acquisition process acquired from the wireless terminal,
A first distance measurement between the first fixed station and the radio terminal, a second distance measurement between the second fixed station and the radio terminal, and between the third fixed station and the radio terminal. Distance correction processing that corrects at least one of the third distance measurements in
A position determination process for determining the position of the wireless terminal based on the first distance measurement value, the second distance measurement value, and the third distance measurement value to which the distance correction process has been performed is executed.
The distance correction process
A first circle centered on the position of the first fixed station and having the first distance measurement value as a radius.
The second circle centered on the position of the second fixed station and the radius of the second distance measurement value, and
After changing the radius of at least one of the third circles centered on the position of the third fixed station and having the third distance measurement value as the radius based on the geometrical relationship of each circle, and changing the radius. It is a process to correct the distance measurement value corresponding to the circle of
The distance correction process further
An intersecting relationship in which two of the first circle, the second circle, and the third circle intersect at two points, or two of the first circle, the second circle, and the third circle contact at one point. The one-point contact relationship is established, and the remaining one circle is included in one of the other two circles, or the remaining one circle includes one of the other two circles. If you do
Under the condition that the crossing relationship or the one-point contact relationship is maintained, or the one-point contact relationship is established for the two circles in the crossing relationship, the radius of the contained circle is reduced. A positioning device that includes an inclusion elimination process that increases the radius of the included circle. In the positioning apparatus according to claim 1,
The inclusion elimination process is
If neither the crossing relationship nor the one-point contact relationship is maintained, and the one-point contact relationship is not established for the two circles in the crossing relationship, the included circle or , A positioning device comprising a process of changing the radius of only one of the contained circles. The distance measurement value between each of the first fixed station, the second fixed station and the third fixed station and the wireless terminal is set to at least one of the first fixed station, the second fixed station and the third fixed station. Or, the information acquisition process acquired from the wireless terminal,
A first distance measurement between the first fixed station and the radio terminal, a second distance measurement between the second fixed station and the radio terminal, and between the third fixed station and the radio terminal. Distance correction processing that corrects at least one of the third distance measurements in
A position determination process for determining the position of the wireless terminal based on the first distance measurement value, the second distance measurement value, and the third distance measurement value to which the distance correction process has been performed is executed.
The distance correction process
A first circle centered on the position of the first fixed station and having the first distance measurement value as a radius.
The second circle centered on the position of the second fixed station and the radius of the second distance measurement value, and
After changing the radius of at least one of the third circles centered on the position of the third fixed station and having the third distance measurement value as the radius based on the geometrical relationship of each circle, and changing the radius. It is a process to correct the distance measurement value corresponding to the circle of
The distance correction process further
An intersecting relationship in which two of the first circle, the second circle, and the third circle intersect at two points, or two of the first circle, the second circle, and the third circle contact at one point. When the one-point contact relationship is established and the remaining one circle does not intersect with any of the other two circles at two points or at one point, the intersection relationship or Of the two circles in the one-point contact relationship, the radii of the far circle and the remaining one circle are changed so as to intersect with the far circle having the longer center distance from the remaining one circle. A positioning device characterized by including processing. The distance measurement value between each of the first fixed station, the second fixed station and the third fixed station and the wireless terminal is set to at least one of the first fixed station, the second fixed station and the third fixed station. Or, the information acquisition process acquired from the wireless terminal,
A first distance measurement between the first fixed station and the radio terminal, a second distance measurement between the second fixed station and the radio terminal, and between the third fixed station and the radio terminal. Distance correction processing that corrects at least one of the third distance measurements in
A position determination process for determining the position of the wireless terminal based on the first distance measurement value, the second distance measurement value, and the third distance measurement value to which the distance correction process has been performed is executed.
The distance correction process
A first circle centered on the position of the first fixed station and having the first distance measurement value as a radius.
The second circle centered on the position of the second fixed station and the radius of the second distance measurement value, and
After changing the radius of at least one of the third circles centered on the position of the third fixed station and having the third distance measurement value as the radius based on the geometrical relationship of each circle, and changing the radius. It is a process to correct the distance measurement value corresponding to the circle of
In the distance correction process,
Within the first circle, the second circle and the third circle, there are two circles in which one contains the other, and the remaining one circle does not include any of the other two circles. , If it is not included in either of the other two circles, the radius of the contained circle of the other two circles is reduced, and the radius of the contained circle is increased. A positioning device characterized in that the inclusion elimination process is executed first. In the positioning apparatus according to any one of claims 1 to 4.
The distance correction process is repeatedly executed a plurality of times.
Each of the distance correction processes
When the radius of the first circle, the second circle, or the third circle is increased or decreased in the distance correction process executed earlier, the first circle, the first circle, said in the distance correction process executed later. A positioning device characterized in that the radius of the second circle or the third circle is not reduced or increased. In the positioning apparatus according to any one of claims 1 to 5,
The intersection of the first circle and the second circle subjected to the distance correction processing, the intersection of the second circle and the third circle subjected to the distance correction processing, and the distance correction processing performed. A positioning device characterized in that the position of the wireless terminal is obtained based on a positioning triangle having the intersection of the third circle and the first circle as an apex. In the positioning apparatus according to claim 6,
When there are a plurality of intersections of the first circle and the second circle to which the distance correction process has been performed, one of the plurality of intersections is set as the first vertex, and the distance correction process is performed. When there are a plurality of intersections between the second circle and the third circle, one of the plurality of intersections is set as the second apex, and the third circle and the first circle subjected to the distance correction process are used. When there are a plurality of intersections, the positioning triangle having one of the plurality of intersections as the third apex is obtained, and when there are a plurality of the positioning triangles, a plurality of the positioning triangles A positioning device characterized in that the position of the wireless terminal is obtained based on a triangle having the smallest total value of the distances between the vertices. In the positioning apparatus according to claim 6,
When there are a plurality of intersections of the first circle and the second circle to which the distance correction process has been performed, one of the plurality of intersections is set as the first vertex, and the distance correction process is performed. When there are a plurality of intersections between the second circle and the third circle, one of the plurality of intersections is set as the second apex, and the third circle and the first circle subjected to the distance correction process are used. When there are a plurality of intersections, the positioning triangle having one of the plurality of intersections as the third apex is obtained, and when there are a plurality of the positioning triangles, a plurality of the positioning triangles A positioning device characterized in that the position of the wireless terminal is obtained based on a triangle having the smallest area. In the positioning apparatus according to any one of claims 6 to 8.
A positioning device characterized in that the position of the wireless terminal is obtained based on the center of gravity of the positioning triangle.

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