JP2013205168A - User terminal and position estimation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable position estimation in only a small number of base stations.SOLUTION: One sound wave base station 3 transmits sound waves in a pulse line in accordance with a predetermined transmission interval and pulse information. Swing motion is applied to a user terminal 1, and a swing detection part 16 detects a swing section from the acquisition direction of a direction sensor part 15. A sound wave receiving part 12 receives the sound waves, and an interval calculation part 14 calculates reception interval of the sound waves in the swing section. A direction estimation part 17 estimates the direction of the sound wave base station 3 during the swing using the principal similar to the Doppler effect on the basis of a difference between a predetermined transmission interval and a predetermined reception interval. A distance estimation part 18 estimates a distance to the sound wave base station 3. On the basis of the estimated direction and distance, a position estimation part 19 estimates a position of the user terminal 1 to the sound wave base station 3 whose position is known.

Description

  The present invention relates to a user terminal and a position estimation system using sound waves (including ultrasonic waves).

  GPS (Global Positioning System) is widely known as a position estimation technique. Since most types of user terminals such as smartphones and mobile terminals support GPS, there is an advantage that anyone can use it easily. On the other hand, in urban areas and indoors, there are problems that the estimation error of the position information increases or the position information cannot be acquired. As a conventional technique for this problem, there are techniques disclosed in Patent Document 1 and Non-Patent Document 1.

  Patent Document 1 discloses a technique capable of estimating a position even indoors by installing a plurality of radio base stations, and estimates the position by exchanging radio signals between the radio base station and the user terminal. Specifically, the position information of the radio base station is assumed to be known, radio signals are exchanged with the radio base station, and the distance from the radio base station is estimated. Similarly, the distance to three or more radio base stations is estimated, and the position information is estimated based on the three-point survey.

  Non-Patent Document 1 discloses a technique capable of estimating the position indoors by installing a plurality of ultrasonic base stations, as in Patent Document 1, and three or more ultrasonic base stations, The position information is estimated by estimating the distance between the user terminals.

JP 2011-214920 A

"A New Location Technique for the Active Office", IEEE Personal Communications, vol. 4, no. 5, pp. 43-47, 1997.

  In Patent Literature 1 and Non-Patent Literature 1, indoor position information can be estimated, but there are the following problems.

  In order to estimate the position, it was necessary to simultaneously exchange signals between three or more base stations (radio base stations and ultrasonic base stations) and user terminals. Therefore, it is necessary to provide a large number of base stations, and there is a problem that the cost is high.

  The objective of this invention is providing the user terminal and position estimation system which solve the subject of the said prior art and enable position estimation only with few base stations.

  In order to achieve the above object, the present invention is able to add a swing operation centered on a predetermined position within a sound wave reception range from one sound wave base station that transmits a sound wave, thereby detecting the predetermined position where the sound wave exists. A user terminal for estimation, a sound wave receiving unit that receives sound waves, information on a predetermined location where each sound wave base station is arranged, a predetermined transmission interval of sound waves that each sound wave transmission base station transmits as a pulse train, and sound wave pulse information A base station specifying unit that specifies from which sound wave base station the received sound wave is transmitted, an orientation sensor unit that acquires the orientation of the user terminal, and the acquired orientation Swing detection for detecting a time interval in which a time change satisfies a predetermined condition and monotonously increases or decreases as a swing interval in which the swing motion is applied to the user terminal And the reception interval of the sound wave transmitted from the specified sound wave base station from the portion of the swing section of the received sound wave to the predetermined transmission interval and the sound wave pulse information in the specified sound wave base station A reception interval calculation unit that calculates based on the direction from the predetermined position to the identified acoustic wave base station, and the magnitude relationship between the calculated reception interval and the transmission interval at the identified acoustic wave base station A direction estimation unit that estimates based on the acquired orientation when attempting to reverse, a distance estimation unit that estimates a distance between the predetermined position and the identified sound wave base station, the estimated direction and And a position estimation unit that estimates the predetermined position on the basis of a predetermined location where the identified sound wave base station is arranged based on a distance.

  In order to achieve the above object, the present invention provides the user terminal, one of the sound wave transmission base stations arranged at the predetermined position, the predetermined position of the sound wave transmission base station, and the A server that stores the predetermined transmission interval and the sound wave pulse information, and allows the base station specifying unit to store the information by notifying the stored information to the base station specifying unit by data communication; It is the position estimation system provided, It is characterized by the above-mentioned.

  According to the present invention, by using transmission sound waves transmitted in a pulse train from a single sound wave base station at a predetermined interval, the user terminals to which a swing operation can be applied receive the transmission sound waves, and the Doppler effect is achieved. Based on a similar principle, the direction of the user terminal when the difference between the reception interval and the transmission interval is to be reversed is estimated as the direction in which the sonic base station exists, and the distance between the sonic base station and the user terminal is estimated. The position of the user terminal with respect to the sound wave base station can be estimated based on the estimated direction and distance. Therefore, only one sonic base station is required when the user terminal estimates the position, and the position can be estimated with only a small number of base stations.

It is a functional block diagram of the position estimation system concerning one embodiment. It is a functional block diagram of a space | interval calculation part. It is a figure which shows the procedure of the position estimation method which concerns on one Embodiment. It is a figure which shows notionally the example of the information of each sound wave base station managed by a server and notified to a user terminal. It is a figure which shows the assumption environment when an outlier removal part determines a threshold value. One example of outlier removal processing is described in the form of a program notation. It is a figure for demonstrating a recalculation process notionally. It is a figure for demonstrating direction estimation. It is a figure for demonstrating position estimation.

  FIG. 1 is a functional block diagram of a position estimation system according to an embodiment of the present invention. The position estimation system 10 includes a user terminal 1, a server 2, and a sonic base station 3. The user terminal 1 includes a communication unit 11, a sound wave receiving unit 12, a base station specifying unit 13, an interval calculating unit 14, an orientation sensor unit 15, a swing detecting unit 16, a direction estimating unit 17, a distance estimating unit 18, and a position estimating unit 19. Including. The outline of each part is as follows.

  As shown in the figure, the communication unit 11 and the server 2 perform data communication via the Internet or the like. The sound wave base station 3 includes a speaker or the like, and continuously transmits a pulse train of sound waves with a predetermined transmission interval according to predetermined sound wave transmission information, and the transmitted sound wave includes a microphone or the like. The configured sound wave receiving unit 12 receives the signal. The sound wave may be an ultrasonic wave.

  The server 2 generally manages information on each of a plurality of sonic base stations 3. The information includes predetermined sound wave transmission information regarding sound waves transmitted by each of the sound wave base stations 3 and information on predetermined positions of the sound wave base stations 3. The sound wave transmission information includes pulse information for specifying each pulse such as a frequency, a pulse width, and a waveform of a pulse wave in the form of a pulse train to be transmitted, and information on a transmission interval between the pulses transmitted according to the pulse information.

  The server 2 notifies the user terminal 1 of the information by data communication. The base station specifying unit 13 stores the notified information, and specifies which sound wave base station 3 transmits the sound wave received by the user terminal 1 by using the information. In the present invention, it is possible to estimate the position of the user terminal 1 with the identified sound wave base station 3 as a reference.

  The interval calculation unit 14 calculates the reception interval of each sound wave transmitted by the sound wave base station 3 with a predetermined transmission interval in the received sound wave. The direction sensor unit 15 includes a geomagnetic sensor, a gyro sensor, and the like, and acquires the orientation of the user terminal 1.

  The swing detection unit 16 is a time interval in which a swing operation applied to the user terminal 1 is added to the user terminal 1 by the user typically holding the user terminal 1 with a hand and swinging in a circular orbit. Detect as.

  The direction estimation unit 17 estimates a direction from the user position when the swing motion is applied, that is, the direction from the rotation center of the swing toward the sound wave base station 3. The distance estimation unit 18 estimates the distance between the user position and the sound wave base station when the swing operation is applied.

  Based on the estimated direction and the estimated distance, the position estimation unit 19 estimates the user position with reference to the sonic base station 3 when the swing motion is being applied. In the present invention, since the position can be estimated, it is sufficient that the user terminal 1 can receive sound waves from only one sound wave base station 3.

  Therefore, compared with the prior art that requires at least three base stations, in the present invention, it is not necessary to provide a large number of sonic base stations 3, and the installation cost can be reduced. In addition, it is possible to widen the range in which sound waves can be received by mounting a loud speaker, and to expand the range in which position estimation can be performed by one sound wave base station 3.

  FIG. 2 is a functional block diagram of the interval calculation unit 14. The interval calculation unit 14 includes a temporary interval calculation unit 41, an outlier removal unit 42, and an interval recalculation unit 43, which are responsible for detailed processing when the interval calculation unit 14 calculates a reception interval. The outline is as follows.

  The temporary interval calculation unit 41 analyzes the received sound wave by dividing it at predetermined transmission intervals by the sound wave base station 3, and corresponds to the sound wave transmitted by the sound wave base station 3 (the part assumed to be compatible) Is temporarily calculated for each location, and the reception interval is temporarily calculated.

  The outlier removal unit 42 calculates the corresponding provisional calculation when the difference between the provisional reception interval obtained from the provisionally calculated reception location and the predetermined transmission interval by the sound wave base station 3 is equal to or greater than a predetermined threshold value. Processing such as excluding the reception location as an outlier is performed.

  The interval recalculation unit 43 recalculates the original reception location that was lost during provisional calculation because the reception location excluded as an outlier was provisionally calculated due to an error. The reception interval as the final output by 14 is obtained.

  FIG. 3 is a diagram showing a procedure of a position estimation method according to an embodiment of the present invention. As illustrated, (Procedure 1) to (Procedure 5) are sequentially executed. The outline of each procedure is as follows. With reference to FIG. 3, the details of the processing of each unit of FIG. 1 and FIG. 2 will be described.

(step 1)
The sound wave base station 3 starts transmitting a pulse train of sound waves composed of predetermined sound wave transmission information according to the setting information managed by the server 2, and thereafter continues the transmission.

(Step 2)
The user terminal 1 acquires information on each sonic base station 3 managed from the server 2 by data communication by the communication unit 11. In the user terminal 1, the sound wave receiving unit 12 starts recording, and the base station specifying unit 13 analyzes the sound recording in a predetermined section longer than each transmission interval of the sound wave base station 3 with each sound wave information, and the user terminal It determines which one of the plurality of sound wave base stations 3 is receiving sound waves from itself.

  FIG. 4 shows an example of information on the respective sound wave base stations. As shown in the figure, each of the sonic base stations 3, 3, 3-2,..., 3 -N has different setting information, for example, in the form of (x, y) coordinates. Position information (X_1, Y_1), (X_2, Y_2), ..., (X_N, Y_N) to be given and acoustic wave transmission information Acoustic_1, Acoustic_2, ..., Acoustic_N are set.

(Step 3)
The swing detection unit 16 detects a swing motion applied to the user terminal 1 as a time interval based on the orientation of the user terminal 1 acquired by the direction sensor unit 15 in real time. Note that in a procedure not shown, the user swings the user terminal 1 around its own position, for example, by holding the user terminal 1 in hand. The swing is an operation that draws a circular orbit having a substantially equal radius around the center.

  Here, specific swing detection may be performed as follows, for example.

  The orientation of the user terminal 1 acquired by the direction sensor unit 15 is assumed to be D (t) (0 ≦ D (t) <360). Here, t represents time, where 0 is north, 90 degrees west, 180 degrees south, 270 degrees east, and the direction value increases counterclockwise. The swing detection unit 16 constantly monitors the direction D (t) that is additionally acquired by updating in real time and obtained as a history up to the current t, and if the following condition 1 or 2 is satisfied, a swing operation is added. It is determined that

Condition 1 (for counterclockwise swing):
D (t_s) <D (t_e) and
D (t_e) -D (t_s)> THRESHOLD1 and D (t) monotonically increases from time t_s to time t_e

Condition 2 (for clockwise swing):
D (t_s)> D (t_e) and
D (t_s) -D (t_e)> THRESHOLD1 and D (t) monotonically decreases from time t_s to time t_e

  When the times t_s and t_e satisfying the condition 1 or the condition 2 exist, the period t_s to t_e are set as the swing period. Here, THRESHOLD1 is a threshold value of the rotation angle of the swing. For example, when THRESHOLD1 = 90 degrees, the swing is determined only when the swing is 90 degrees or more, and the swing section is detected.

  That is, when a section [t_s, t_e] in which the monotonic increase or monotonic decrease continues over an angle larger than THRESHOLD1 in the orientation history D (t) is detected, the section [t_s, t_e] is swung. A swing is detected as a section. Further, a section obtained by extending the section [t_s, t_e] as much as possible is not monotonically increasing or decreasing. Even when the orientation value crosses 0 degree or 360 degrees, the change in the value itself is read as a continuous change, so that the monotonic increase or the monotonic decrease is appropriately determined.

In addition, in the conditions 1 and 2, the following conditions a and / or b may be imposed to perform the swing determination.
Condition a t_s−t_e> THRESHOLD_a
Condition b t_s−t_e <THRESHOLD_b

  Here, THRESHOLD_a and THRESHOLD_b are respectively predetermined threshold values for excluding rotations that are too fast and rotations that are too slow from being detected as normal swings (when both are used, THRESHOLD_a <THRESHOLD_b is defined).

(Step 4)
From the recording of the sound wave receiving unit 12 in the swing section [t_s, t_e] detected in (Procedure 3), the interval calculation unit 14 obtains the reception interval by obtaining the location where the sound wave transmitted by the sound wave base station 3 is received. The direction of the user terminal 1 obtained by the azimuth sensor unit 15 is recorded at the sound wave reception location. The calculation of the reception interval is performed by the following three steps (provisional calculation of the reception interval), (removal of outliers), and (recalculation of the reception interval) as follows.

(Tentative calculation of received location)
The temporary interval calculation unit 41 obtains the reception location of the sound wave in the swing section as an intermediate output in the interval calculation unit 14, and temporarily calculates the reception interval.

  In order to explain the provisional calculation, symbols are defined as follows. Let S (i) (i = 1, 2,..., N) be a recording in a swing section, that is, a received sound wave sample. Here, n is the received sample length. That is, the received sample at the start time t_s of the swing section [t_s, t_e] is S (1), the received sample at the end time t_e is S (n), and the i-th received sample is S (i). .

  Also, it is assumed that the sound wave transmission interval at the sound wave base station 3 that is transmitting the received sound wave corresponds to the width of the received sample SI. (In other words, the actual transmission interval is equal to SI multiplied by the sampling interval of sound wave reception.) Note that the transmission interval is appropriately referred to as “transmission interval SI” on the assumption that there is such a correspondence.

The provisional calculation of the reception time is performed by the following procedures (1) to (4).
(1) Set the counter variable k to the initial value k = 0, and proceed to (2).
(2) Calculate the sound wave reception time R (k + 1) from the range of S (k * SI + 1) to S ((k + 1) * SI), and proceed to (3).
(3) If (k + 1) * SI <n, return to (2) with k = k + 1, otherwise go to (4) with k = k + 1.
(4) The process ends with the calculated number of reception times m = k.

  According to the above procedure, the sound wave reception time R (k) (k = 1, 2,..., M) is calculated, and the reception interval is also obtained. Note that this calculation is a provisional calculation for final output as described above. As a general method for calculating the reception time of (2), there is a method using a correlation value. Specifically, a reference signal (a signal including one pulse in the transmitted pulse train) is created from the sound wave transmission information, and the reference signal and the received sample S (i) (i is the range specified in (2). The point at which the correlation value of (inside) becomes the maximum is the reception time R (k).

  In the present invention, the sound wave transmission interval and the reception interval are substantially equal. Therefore, if the received sample S (i) is divided by the number of samples SI corresponding to the transmission interval, there is always one reception location in each section on the assumption that sound wave reception and recording are performed normally. Will exist. In the above procedure, this is used to simply temporarily calculate the reception location.

  If there is a received sound wave at the end of the range set in step (2) above, the sound wave pulse adjacent to the first part and the last part of the received sample divided into SI pieces Therefore, the reception time R (k) cannot be obtained appropriately.

As another example of the procedure (2) in which measures against this are taken, the following may be performed. Only when k = 0, the width of the range (2) is expanded from SI to, for example, x * SI to obtain R (1). Here, x is a constant of 1 <x <2, and for example, x = 1.5 may be set. That is, if k = 0, (2)
S (1) -S (x * SI)
And R (1) is calculated as the maximum location of the correlation value with the reference signal from the range.

After k = 1, the range of (2) is set so that when a true sound wave reception location (not noise etc.) is provisionally calculated, it is calculated near the middle of SI intervals.
S ((k−1 / 2) * SI + R (1) + 1) to S ((k + 1/2) * SI + R (1))
R (k) is calculated as follows. When the value of i in S (i) that defines the above range is no longer an integer due to the division by SI / 2, the range may be appropriately shifted by 1/2 of the sampling interval.

  In addition, when specifying the sound wave base station 3 that is transmitting the received sound wave in the base station specifying unit 13 described above, recording at least longer than the sound wave transmission interval is referred to the sound wave pulse of each sound wave base station 3. The maximum value of the correlation value is obtained as a signal, and the sound wave base station 3 that maximizes the maximum value may be specified as the base station that transmits the sound wave.

(Remove outliers)
The outlier removal unit 42 has erroneously determined reception from the reception time R (k) from the information of the provisionally calculated reception time R (k), transmission interval SI, and threshold value THRESHOLD described later. Exclude things as outliers. Here, as an outlier, a reception time R (k) when a reflected wave, noise, or the like is erroneously calculated can be considered. By removing outliers, the direction estimation unit 17 can be expected to improve accuracy.

  For this reason, the outlier removal unit 42 first obtains the threshold value THRESHOLD by two steps of [detection of swing angular velocity] and [determination of threshold value] as follows.

[Detection of swing angular velocity]
The angular velocity w of the swing is calculated by the following formula.
w = | D (t_e) −D (t_s) | / (t_e−t_s)
The symbols are as described above. That is, since the orientation D (t) of the user terminal 1 acquired by the azimuth sensor unit 15 in the swing section [t_s, t_e] is recorded, refer to the value at the time of t = t_e, t_s. The angular velocity w can be obtained by

[Determination of threshold]
Determine the threshold THRESHOLD for removing outliers. Fig. 5 shows the assumed environment for determining the threshold. Here, the user position that is the center of the swing is a point P, the swing radius of the user terminal 1 is R, the swing trajectory is S1, and the position of the sound wave base station 3 is a point Q. Of each sound wave transmitted as a pulse train with a transmission interval SI, the swing angle θ from reception of a certain sound wave p to reception of the next sound wave p + 1 can be calculated by the following equation.
θ = w * SI
Here, the swing speed w is assumed to be constant over the swing section.

  A change in the distance between the user terminal 1 and the sound wave base station 3 after receiving a certain sound wave p until receiving the next sound wave p + 1 is defined as DC (R, θ). Considering the position of the user terminal 1 at which DC (R, θ) is maximum, the maximum is obtained when the reception positions of the sound waves p and p + 1 are point P1 and point P2, respectively, as shown in FIG.

  Here, if the case of a single series of reception positions is fixed, the points P1 and P2 that give the maximum value in the series of reception positions are the user who received the sound wave pulse sequentially. This is the point at which the terminal 1 is located and the direction of the line segment P1P2 is closest to the direction of the tangent L of the swing trajectory S1 passing through the position Q of the sound wave base station 3. In other words, the line segment P1P2 is defined by two points that are adjacent to each other, and that the line segment that connects the points is closest to the tangent line L among the two adjacent points that have sequentially received the sound wave pulse. In some cases, two tangents L are determined with respect to the swing path S1, and in this case, the tangent on the side closer to the line segment P1P2 under consideration is used. In the figure, the point T is a contact point of the tangent line L with respect to the swing path S1.

Furthermore, considering the ideal case of a certain series of receiving positions, points P1 and P2 exist so that the line segment P1P2 closest to the direction of the tangent L is parallel to the tangent L. In this case, the maximum possible value DCmax (R, θ) of the distance change DC (R, θ) is obtained. Specifically, it is expressed by the following formula.
DCmax (R, θ) = 2 * R * sin (θ / 2)

Consider realistic DCmax (R, θ) values. The swing radius R can be assumed to be approximately the same as the length of the user's arm. Since the length of an adult male's arm is about 0.7 m, R = 0.8 m with a margin. The maximum distance change DCmax (θ) in this case is expressed by the following equation.
DCmax (θ) = 1.6 * sin (θ / 2)

Finally, the threshold THRESHOLD [seconds] is determined from DCmax (θ) by the following equation. Here, v represents the speed of sound.
THRESHOLD = DCmax (θ) / v

  As described above, the threshold THRESHOLD is determined by the swing angle θ when receiving two adjacent sound pulses determined by the detected angular velocity w of the swing and the transmission interval SI, and the predetermined values assumed as the swing radius R and the sound velocity v. Can be determined. At this time, in particular, the swing radius R may be a predetermined value assumed as the upper limit value of the user's arm length.

  As described above, after performing [detection of swing angular velocity] and [determination of threshold value] as preprocessing, the outlier removal unit 42 removes outliers from information on the threshold THRESHOLD, transmission interval SI, and reception time R (k). . As a policy, when the difference between the transmission interval SI and the reception interval (hereinafter referred to as the interval difference) is equal to or greater than a threshold value THRESHOLD, the corresponding sound wave is removed as an outlier.

  FIG. 6 shows an embodiment of the outlier removal process in a simple program notation format. Outlier removal may be performed by other methods.

First, 16 lines 1 is represents the processing of the division of the set of sound waves, here divides the m-number of waves set A, the subset B _i of the sound waves interval difference is less than the threshold THRESHOLD . number is the number of divided subset B _i. If number is 1, it is determined that there is no outlier and the process ends.

On the other hand, when the number is larger than 1, the direct value is determined from the 18th line to the 23rd line, and the outlier removal process is performed. That is, the subset B _direct having the maximum number of elements from the plurality of extracted subsets B _j is determined as a set of sound waves that can be correctly calculated, and other sound waves are determined as outliers and removed.

Note that in FIG. 6, only the process of determining the direct value for specifying the subset B _direct is described, and the process of the part to be actually removed is not described, but the outlier removal unit 42 Perform the removal process.

Note that the process of dividing the set of sound waves from the first line to the 16th line is as described in the program, but the main part is roughly as follows. In the first row, each sound wave reception time R (k) (k = 1, 2, ..., m) is prepared as the index set A, and the outlier is removed in the subsequent processing. Further, each subset B _i = {n _i , n _i +1,..., M _i −1, m _i } is distributed. Each subset B _i is initially prepared as an empty set φ.

When distributing the sequentially removes the first element of A -; with (line 8 'A' = A '{z} "A' temporary variable A), add the deleted to sequentially B _i min While (line 10), the following determination is made sequentially. That is, where a two adjacent elements, reception interval between the last element y of the first element z (such as line 8) and B _i of A (such as line 8) | R (z) -R (y) | and the difference is less than THRESHOLD (9 line) between the transmission interval SI, the spacing difference means that not more than THRESHOLD, then remove the element from the a to B _i Continue the process of adding.

If it is determined in the determination that the interval difference is equal to or greater than THRESHOLD, B _i and B _{i + 1} are separated from the determined element as a boundary. Thus, for example, if R (4) is removed for A = {1,2,3,4,5,6,7}, then B ₁ = {1,2,3} and B ₂ = { 5,6,7} will be obtained.

(Recalculation of reception interval)
When one or more sound waves are removed by the above outlier removal process, the interval recalculation unit 43 calculates the reception time of the sound wave again, and recalculates the reception interval from the recalculated time. This is the final output of the interval calculation unit 14. This increases the number of sound waves that can be used for direction estimation, and has the effect of contributing to improving the accuracy of direction estimation.

  When there is no outlier to be removed (corresponding to number = 1), the interval recalculation unit 43 does not change the reception interval calculated by the temporary interval calculation unit 41, and the final calculation of the interval calculation unit 14 Output.

  Consider a case where the reception time R (q) of the sound wave q (1 <= q <= m) is removed. The reception time R (q) is calculated again by the following procedures (1) to (3).

(1) Among the elements p of the sound wave set B _direct that can be calculated correctly, the element having the minimum | p−q | is defined as p ′.
(2) min = R (p ') + (q−p ′) * SI−THRESHOLD,
max = R (p ′) + (q−p ′) * SI + THRESHOLD.
(3) Sound wave reception time R (q) is recalculated from the range of reception samples S (min) to S (max).

  Here, in the recalculation process of (3), a method for obtaining a point where the correlation value with the reference signal is maximized can be used as in the provisional calculation.

In the recalculation, when there are a plurality of excluded sound waves q, the above steps (1) to (3) are sequentially executed for each sound wave q. In this case, re-calculated wave q is while updating the set B _direct by sequential addition to the elements of the set B _direct the sound waves correctly calculated, the procedure for the remaining sound waves q recalculation is not performed (1) - Continue (3).

  FIG. 7 is a diagram for conceptually explaining the recalculation process. (A) represents before recalculation, (B) represents after recalculation, and in each of the sections [1] to [4], the interval temporary calculation unit 41 temporarily calculated R (k) S ( k * SI + 1) to S ((k + 1) * SI), black circles (●) or white circles (○) are provisionally calculated R (k), of which white circles are (A ) Represents an outlier, and (B) represents a recalculated value.

  In other words, in (A) before recalculation, the white circles (○) in [3] were determined to be outliers because the other black circles (●) were largely disturbed by being equally spaced. It is. On the other hand, the range of S (min) to S (max) is set as shown in (B) within a predetermined range that is approximately equidistant by the procedure (2). By recalculating R (q) from step (3) again, as shown by white circles (○) in (B), positions that are lined up at regular intervals in the same manner as other black circles (●). Can be determined.

  Note that in step (2), the width is 2 * THRESHOLD centering on the position shifted from the correctly received R (p ') by an integer number of SI (q-p'; the shift direction is indicated by positive and negative). Therefore, the ranges S (min) to S (max) can be determined so as to be substantially equally spaced as shown in (B). In addition, by correcting the equation in step (2), set S (min) to S (max) as a range in which the width is not 2 * THRESHOLD but a predetermined number of times THRESHOLD, with the shifted position as the center. It may be determined.

The outlier removal unit 42 removes all but the set B _direct made up of a series of adjacent received sound waves, and only one is removed as shown by the white circles in FIG. However, in FIG. 7, only one isolated white circle is shown for convenience of explanation for the recalculation process.

In addition, in the recalculation, when there are a plurality of excluded sound waves q, when the procedures (1) to (3) are sequentially performed for each sound wave q, the processing order of the target sound waves q is a predetermined order. For example, the reception time may be determined sequentially from the earliest side or the latest side. Alternatively, the order may be determined by sequentially selecting the smallest difference in reception time with the elements of the set B _direct of sound waves calculated correctly at each update time. Specifically, it may be determined as follows.

First, the difference diff (q) in reception time is determined as follows. Among the elements p of the correctly calculated sound wave set B _direct (including the case where the above recalculated sound wave q is added and updated), the difference between the reception time and the reception time of the sound wave q | R ( p) -R (q) | elements to minimize, including relying on sound waves q is denoted by p = p _min (q), the difference between the reception time in the case of p = p _min (q) As a function of the sound wave q, diff (q) = | R (q) −p _min (q) |

In this way, the processing order of each sound wave q may be determined by sequentially selecting q that minimizes the value of diff (q). In this case, the recalculated q is added to the correctly calculated sound wave set B _direct , and the subsequent diff (q) is obtained.

  (Step 5)

  The distance estimating unit 18 estimates the distance between the user terminal 1 and the sound wave base station 3, and the direction estimating unit 17 is the direction from the user terminal 1 to the sound wave base station 3, more precisely, the swing center at the time of swing. The direction from the user position to the sound wave base station 3 is estimated, and the position estimation unit 19 estimates the position of the user terminal 1 with reference to the sound wave base station 3 based on the estimated distance and direction. Specifically, each estimation is as follows.

(Distance estimation)
The distance estimation unit 18 estimates the distance from the sound wave base station 3 from the received sound wave information. Generally, as a known distance estimation method using sound waves, a method using propagation time and a method using received power are known.

  In the method using the propagation time, the distance can be estimated by calculating the propagation time of the sound wave and multiplying the propagation time by the speed of sound. In this case, separately from the sound wave used for direction estimation, the sound wave base station 3 transmits a predetermined sound wave for distance estimation at a longer transmission interval, and the sound wave receiving unit 12 transmits the sound wave for distance estimation. It may be received and the distance estimation unit 18 may estimate the distance.

  The information on the sound wave for distance estimation includes information associating the transmission time with the transmission sound wave, and is acquired as accompanying information in (Procedure 2). The transmitted sound wave information can be configured in the same manner as the direction information sound wave pulse information. The user terminal 1 and the sound wave base station 3 synchronize time information in advance, and the distance estimation unit 18 obtains the propagation time as the difference between the sound wave reception time and the transmission time, and estimates the distance by multiplying by the sound speed.

  When a distance estimation sound wave is used separately from the direction estimation sound wave, the distance estimation is performed as close as possible at the time of direction estimation immediately before or after the direction estimation is performed. If the user does not move between the direction estimation and the distance estimation, it may not be the latest.

  In the method using the received power, the distance can be estimated from the magnitude of the received power. In this case, a sound wave for direction estimation may also be used for distance estimation. The sound wave transmission information further includes information on the initial power at the time of transmission by the sound wave base station 3. The distance estimating unit 18 can calculate the propagation distance from the received power and the initial power by using the fact that the received power is determined as a predetermined function of the initial power and the propagation distance of the sound wave.

(Direction estimation)
The direction estimation unit 17 performs a swing based on the sound wave reception interval obtained by the interval calculation unit 14 and the direction of the user terminal 1 acquired by the direction sensor unit 15 at the sound wave reception time corresponding to each reception interval. A direction from the user terminal 1 to the sound wave base station 3 is estimated. For the direction estimation, the method shown in Non-Patent Document 2 or Patent Document 2 can be used, but since the swinging terminal does not transmit the sound wave but receives it, the sound wave is different in the present invention. The processing of the base station 3 is simplified.

[Non-Patent Document 2] "Proposal of relative direction estimation method using sound waves", IEICE 2010 Society Conference, B-7-47.
[Patent Document 2] JP 2012-042244 A

  FIG. 8 is a diagram for explaining the direction estimation. (A) includes the position P of the user who performs the swing of the user terminal 1, the arc S1 as the locus of the swing, and the points on the arc S1 at which the sound wave receiving unit 12 received each of the pulse sound waves during the swing. Q1, Q2, Q3, Q4 and Q5, the position Q of the sound wave base station 3, and the propagation of sound waves W1, W2, W3, W4 reaching the position Q from each of the points Q1, Q2, Q3, Q4 and Q5 And W5. In (B), in addition to the explanation of (A), examples of the time t1 to t5 at each point Q1 to Q5 in (A) and the terminal orientation of the user terminal 1 at the position and time are illustrated. Is shown as

  When the swing detection unit 16 detects a swing section as a time section, the direction estimation unit 17 receives, as information necessary for direction estimation, each time ti and each time when the sound wave from the sound wave base station 3 is received in the section. The information of the direction D (ti) acquired by the direction sensor unit 15 is acquired. Here, each time ti is a corresponding reception time when the interval calculation unit 14 calculates the reception interval. For example, in FIG. 8, the terminal orientations 0 ° to 180 ° with respect to the times t1 to t5 in (B) are acquired for the swing section detected for the swing motion R in (A).

  On the other hand, the transmission interval information in the sound wave base station 3 that is the transmission source that receives the sound wave in (Procedure 2) is known in advance, and an example of the transmission interval and an example of the reception interval calculated by the interval calculation unit 14 Are shown in FIG. 8C.

  That is, the transmission interval is set equal to 100 ms. On the other hand, the reception interval corresponding to each section divided by each time t1 to t5 (transmission time) has values of 99 ms, 100 ms, and 101 ms. In a section t2-t1 (representing a section from time t1 to t2, the same applies hereinafter), “transmission interval−reception interval = + 1 ms” and “transmission interval> reception interval”. This is because, as shown in (A), in the section t2-t1, sound waves are received while the user terminal 1 moves so as to approach the position Q where the sound wave base station 3 that is the sound source of the sound wave pulse exists. .

  Conversely, in the sections t4−t3 and t5−t4, “transmission interval−reception interval = −1 ms” and “transmission interval <reception interval”. This is because, as shown in (A), in the sections t4-t3 and t5-t4, the user terminal 1 receives sound waves while moving away from the position Q where the sound wave base station 3 that is the sound wave sound source exists. Because it is.

  On the other hand, since the interval t3-t2 is a mixture of moving closer and moving away, "transmission interval ≒ reception interval", and as is clear from (A), the direction PQ to be estimated is within the interval The direction that exists.

  Thus, the direction estimation unit 17 is based on the principle similar to the Doppler effect, and the direction indicated by the direction sensor unit 15 in the section when the magnitude relationship between the transmission interval and the reception interval is about to be reversed is determined by the mobile terminal 2. Estimated as an existing direction. Note that for the section t3-t2 when the magnitude relationship is about to reverse, the estimated direction may be assigned a direction at the time of either the end point t2 or t3, or a predetermined point in the section, for example, A direction at the time of the midpoint (t2 + t3) / 2 may be assigned.

  In addition, in the example of FIG. 8, the magnitude relationship between the transmission and reception intervals is reversed from “transmission interval> reception interval” to “transmission interval <reception interval”. On the contrary, when reversing from “transmission interval <reception interval” to “transmission interval> reception interval”, in the same manner as in the discussion of FIG. The added direction) is the estimated direction. When the swing is performed 360 °, the reverse rotation appears twice in a section 180 ° apart.

  Therefore, more generally, the direction estimation unit 17 determines the transmission interval from a predetermined direction based on the direction indicated by the direction sensor unit 15 when the magnitude relationship between the transmission interval and the reception interval is switched, that is, because the transmission interval is longer. If the direction is reversed to a shorter relationship, the direction indicated by the azimuth sensor unit 15 is changed to the direction indicated by the azimuth sensor unit 15 if the transmission interval is changed from a shorter relationship to a longer transmission interval. The reverse direction is estimated as the direction in which the sonic base station 3 exists.

  The swing trajectory may be an arc or a circle that is substantially horizontal on a plane that can designate the direction of the sonic base station 3 on the plane. Such a trajectory can be realized when the variation of the radius when the user swings the tracking terminal 1 by hand is within a predetermined range.

(Position estimation)
The position estimation unit 19 estimates the position of the user terminal 1. From the position information (X_A, Y_A) of the acoustic wave base station 3, the estimated distance Distance_A, and the estimated direction Direction_A, the position (X, Y) of the user terminal is estimated by the following equation.
X = X_A + Distance_A * sin (Direction_A)
Y = Y_A−Distance_A * cos (Direction_A)

  Here, the estimated direction Direction_A is 0 degrees north, 90 degrees west, 180 degrees south, 270 degrees east, and the direction value increases counterclockwise in the same way as the acquisition direction of the direction sensor unit 15. And FIG. 9 shows the coordinate relationship in the position estimation. The point P is the position (X, Y) of the user terminal 1, the point Q is the position (X_A, Y_A) of the sound wave base station 3, and the position P of The position is fixed.

  As described above, according to the present invention, the number of base stations necessary for position estimation can be reduced from the conventional three to one. Thereby, reduction of the deployment cost of a base station can be expected.

  Moreover, the following can be considered as an application example of the present invention.

  Route guidance at shopping malls, supermarkets, underground malls, libraries, etc. When you want to go to a store you are interested in at a shopping mall, or when you want to go to a meat corner at a supermarket, the current value and the route to the destination are provided. At this time, it is necessary to install a plurality of sound wave base stations 3 in advance and set transmission sound wave information. The role of the sonic base station 3 can be assigned to a speaker that broadcasts information or an existing speaker that plays music.

  DESCRIPTION OF SYMBOLS 10 ... Position estimation system, 1 ... User terminal, 2 ... Server, 3 ... Sound wave base station, 11 ... Communication part, 12 ... Sound wave reception part, 13 ... Base station specific part, 14 ... Space | interval calculation part, 15 ... Direction sensor part , 16 ... Swing detection unit, 17 ... Direction estimation unit, 18 ... Distance estimation unit, 19 ... Position estimation unit

Claims (8)

Within a sound wave reception range from one sound wave base station that transmits sound waves, a user terminal that estimates the predetermined position where it exists by adding a swing operation centered on a predetermined position,
A sound wave receiver for receiving sound waves;
Information on a predetermined location where each sound wave base station is arranged, a predetermined transmission interval of sound waves transmitted by each sound wave transmission base station as a pulse train, and sound wave pulse information are stored, and the received sound wave is transmitted from any sound wave base station. A base station identifying unit that identifies whether or not
An orientation sensor unit for acquiring the orientation of the user terminal;
A swing detection unit that detects a time interval in which the acquired time change satisfies a predetermined condition and monotonously increases or decreases as a swing interval in which the swing motion is applied to the user terminal;
The reception interval of the sound wave transmitted from the specified sound wave base station is calculated based on the predetermined transmission interval and the sound wave pulse information in the specified sound wave base station from the part of the swing section of the received sound wave. A reception interval calculation unit,
The direction from the predetermined position to the specified sonic base station is acquired when the magnitude relationship between the calculated reception interval and the transmission interval at the specified sonic base station is to be reversed. A direction estimator for estimating based on the direction;
A distance estimator for estimating a distance between the predetermined position and the identified sound wave base station;
A user terminal comprising: a position estimation unit that estimates the predetermined position with reference to a predetermined location where the specified acoustic wave base station is arranged based on the estimated direction and distance.   The reception interval calculation unit calculates the reception interval by dividing the swing interval into the predetermined transmission intervals and obtaining a portion that matches the sound wave pulse information from each interval as a reception time. The user terminal according to 1. The reception interval calculator is
From each section, the provisional reception interval is calculated by obtaining the provisional reception time by obtaining the time when the correlation value with the reference signal generated from the sound wave pulse information is maximum, and the reception order is set to the provisional reception time. A provisional temporary calculation unit to be provided;
Among a series of temporary reception intervals in which the difference between the temporary reception interval and the predetermined transmission interval keeps within a predetermined first threshold, the reception interval in which the maximum number of temporary reception times can be calculated correctly An outlier removal unit that determines a set of the above and excludes the provisional reception time corresponding to the other part as an outlier;
A value obtained by multiplying the predetermined transmission interval by an integer equal to the difference in the given reception order when shifting from the reception time in the correctly calculated reception interval set to the excluded provisional reception time. Only when the correlation value with the reference signal generated from the sound wave pulse information is maximized within a predetermined range centered on the time shifted from the reception time in the set of reception intervals that can be correctly calculated. Then, the original reception time corresponding to the excluded provisional reception time is recalculated, and the reception time based on the reception time in the set of reception intervals that can be correctly calculated and the recalculated reception time. The user terminal according to claim 2, further comprising: an interval recalculation unit that calculates a reception interval calculated by the interval calculation unit.   The outlier removal unit adds a radius of a predetermined upper limit value to the arc in the swing motion during the predetermined transmission interval at an angular velocity of the swing given as an average rate of change of the acquired direction in the swing section. The user terminal according to claim 3, wherein the first threshold value is defined as a value obtained by dividing a linear movement distance when the swing motion is assumed by a predetermined value assumed as a sound speed.   4. The interval recalculation unit determines, based on the first threshold value, a width of the predetermined range centered on a time shifted from a reception time in the correctly calculated reception interval set. Or the user terminal of 4.   Each time the interval recalculation unit recalculates the reception time, it adds the recalculated reception time to the set of reception intervals that have been correctly calculated, and supports the excluded temporary reception times according to a predetermined order. The user terminal according to claim 3, wherein recalculating the original reception time is repeated.   The interval recalculation unit, as the predetermined order, of the excluded provisional reception time, in order from the one that minimizes the time difference between the reception time in the set of reception intervals correctly calculated, The user terminal according to claim 6, wherein the corresponding original reception time is recalculated. A user terminal according to any one of claims 1 to 7,
One of the sound wave transmission base stations arranged at the predetermined location;
By storing the predetermined location of each of the sound wave transmission base stations, the predetermined transmission interval, and the sound wave pulse information, and notifying the stored information to the base station specifying unit by data communication And a server that enables the base station specifying unit to store the position estimation system.