JP6914647B2 - Position estimation device, position estimation program and position estimation method - Google Patents

Description

The present invention relates to a position estimation device, a position estimation program, and a position estimation method. For example, a position estimation device and a position that track a path of a reflected wave indoors using an environmental model and estimate a position using the path. It can be applied to the estimation program and the position estimation method.

In recent years, indoor positioning technology has been attracting attention. Especially indoors where GPS signals do not reach, indoor positioning technology is required for the purpose of detecting the flow line of personnel and managing materials in factories.

For example, the position estimation technology is often used in an environment where the visibility is not good, such as in the shadow of an outdoor building or in an indoor shadow, and it is strongly desired to be able to estimate the position with high accuracy even in an environment where the visibility is not good. ing. Further, the position estimation accuracy is required to be high within about 50 [cm].

Patent Document 1 discloses a position estimation method using radio waves, and discloses a method of estimating the arrival direction of a transmitter by using a diffracted wave even outside the line of sight where no direct wave arrives.

Patent Document 2 is a position estimation method using radio waves, and in order to improve estimation accuracy, a method in which directivity is given to the irradiation of radio waves, the direction of arrival of the transmitter is predicted on the receiving side, and the direction of the transmitting antenna is followed. Is disclosed.

Patent Document 3 is a position estimation method using sound waves, and discloses a method of performing position estimation including a reflected wave in addition to a direct wave.

International Publication No. 2010/038468 Japanese Unexamined Patent Publication No. 2006-170698 Japanese Unexamined Patent Publication No. 2014-98568

However, the technique described in Patent Document 1 estimates from the ratio of vertically polarized waves and horizontally polarized waves that the type of the incoming wave is one of the direct wave, the diffracted wave, and the incoming wave of the reflected wave. If there is no direct wave, it is presumed that the transmitter is in the direction of the diffracted wave whose arrival direction is almost the same as the direct wave. Since the technique described in Patent Document 1 uses only diffracted waves, it is not possible to completely estimate the position outside the line of sight, and it is not possible to estimate the position using only the reflected waves outside the line of sight. Further, in the technique described in Patent Document 1, since the arrival direction of the diffracted wave is estimated as the position of the transmitter, the position estimation accuracy may be inaccurate.

The technique described in Patent Document 2 uses the ray tracing method and a directional antenna to accurately estimate the arrival direction of radio waves. The receiving side detects the Doppler frequency, notifies the moving direction from the receiving side to the transmitting side by a telephone line so as to follow the movement of the radio, and controls the direction of the transmitting antenna. It is a large-scale system in which the receiver and transmitter are linked, and the cost is high. In addition, since the non-line-of-sight is not taken into consideration, if the error in the movement direction estimation becomes large outside the line-of-sight, the position estimation accuracy will be inaccurate in the time from returning to the line-of-sight until the direction estimation is restored. There is a risk.

Since the technique described in Patent Document 3 is premised on the use of direct waves, it is not possible to estimate the position outside the line of sight. Further, since the extension region in the sound source direction is premised on a region in which an angle estimation error is added around a straight line along the sound source direction, the position estimation error is large.

In view of the above problems, the present invention can perform position estimation detection even in an environment with poor visibility (out of line of sight), can be constructed with a simple system that does not require cooperation between the receiving side and the transmitting side, and is more than ever. Provided are a position estimation device, a position estimation program, and a position estimation method capable of estimating a position with high accuracy.

In order to solve such a problem, the first invention is in a position estimation device that estimates the transmission position of a transmission wave including a signal diffusely modulated by the transmission side based on the reflected wave of the transmission wave. And (2) the diffusion-modulated signal wave contained in each received signal is acquired from each receiving unit, and the correlation between each signal wave component and the waveform data of the preset transmitted wave is obtained. The position where the correlation value becomes the maximum value is set as the head position of the direct wave, and the signal component of the direct wave is subtracted from the received signal to separate the reflected wave contained in the received signal. , (3) Time difference detection unit that detects the arrival time difference of each reflected wave that has arrived at each receiving unit by mutual correlation of each reflected wave separated by each separation processing unit, and (4) Arrival time difference of each reflected wave. The arrival angle estimation unit that estimates the arrival angle of each reflected wave based on, and (5) the arrival path of each reflected wave is tracked based on the arrival angle of each reflected wave, and the intersection of the arrival paths of each reflected wave is determined. It is characterized by including a position estimation unit that estimates as a transmission position of a transmission wave.

The second invention is in a position estimation program that estimates the transmission position of a transmission wave including a signal diffusely modulated by the transmitting side based on the reflected wave of the transmission wave included in the incoming wave captured by each of a plurality of receiving units. , (1) Obtain the diffusion-modulated signal wave contained in each received signal from each receiving unit, correlate each signal wave component with the preset waveform data of the transmitted wave, and correlate with each other. A plurality of separation processing units that separate the reflected wave contained in the received signal by subtracting the signal component of the direct wave from the received signal with the position where the value becomes the maximum value as the head position of the direct wave, and (2). A time difference detection unit that establishes the mutual correlation of each reflected wave separated by each separation processing unit and detects the arrival time difference of each reflected wave that has arrived at each receiving unit, and (3) each based on the arrival time difference of each reflected wave. The arrival angle estimation unit that estimates the arrival angle of the reflected wave, and (4) traces the arrival path of each reflected wave based on the arrival angle of each reflected wave, and transmits the transmission wave at the intersection of the arrival paths of each reflected wave. It is characterized in that it functions as a position estimation unit that estimates as a position.

A third aspect of the present invention is a position estimation method in which the transmission side estimates the transmission position of a transmission wave including a diffusion-modulated signal based on the reflected wave of the transmission wave. Captured, (2) each of the plurality of separation processing units acquires the diffusion-modulated signal wave contained in each received signal from each receiving unit, and waveform data of each signal wave component and preset transmission wave. The position where the maximum correlation value is obtained is set as the head position of the direct wave, the signal component of the direct wave is subtracted from the received signal, and the reflected wave contained in the received signal is separated (3). ) The time difference detection unit takes the mutual correlation of each reflected wave separated by each separation processing unit, detects the arrival time difference of each reflected wave that has arrived at each receiving unit, and (4) the arrival angle estimation unit detects each reflection. The arrival angle of each reflected wave is estimated based on the arrival time difference of the wave, and (5) the position estimation unit tracks the arrival path of each reflected wave based on the arrival angle of each reflected wave, and the arrival path of each reflected wave. It is characterized in that the intersection of is estimated as the transmission position of the transmitted wave.

According to the present invention, position estimation detection can be performed even in an environment with poor visibility, a simple system that does not require cooperation between the receiving side and the transmitting side can be constructed, and a more accurate position can be estimated.

It is a block diagram which shows the internal structure of the receiver which concerns on 1st Embodiment. It is explanatory drawing explaining the environment which performs the position estimation which concerns on 1st Embodiment. It is an internal block diagram which shows the internal structure of the transmitter which concerns on 1st Embodiment. In the first embodiment, it is a figure which shows the waveform (transmission signal) of the ultrasonic signal transmitted by a transmitter, and the waveform of the received signal received by a receiver. It is explanatory drawing explaining the case where the reflected wave is buried during the reverberation time of a direct wave. It is a flowchart which shows the separation process which separates the reflected wave by the separation process part which concerns on 1st Embodiment. It is a figure which shows the signal waveform example of the ultrasonic signal which concerns on 1st Embodiment. It is a figure which shows the state when the reflected wave is out of phase of a direct wave. It is explanatory drawing explaining the code diffusion modulation of an ultrasonic signal. It is a figure which shows the waveform of the direct wave and the reflected wave at the time of code diffusion modulation. It is explanatory drawing explaining the correlation value detection processing and time difference detection processing which concerns on 1st Embodiment. It is explanatory drawing explaining the basic concept of the arrival angle estimation process which concerns on 1st Embodiment. It is explanatory drawing explaining the arrival direction estimation process which concerns on 1st Embodiment. It is a flowchart which shows the position estimation process which concerns on 1st Embodiment. It is explanatory drawing explaining the position estimation process which concerns on 1st Embodiment. It is explanatory drawing explaining the position estimation process of a transmission point using a ray trace method. It is explanatory drawing explaining the position estimation process of 3D coordinates. It is explanatory drawing explaining the position estimation process at the time of having a plurality of intersections. It is a flowchart which shows the limitation process of the number of reflections by the reflection number counting part which concerns on 1st Embodiment. In the first embodiment, it is a flowchart which shows the process of selecting a highly reliable signal wave from a plurality of signal waves. It is a figure which shows the received wave in the receiver which concerns on 1st Embodiment. It is explanatory drawing explaining the position estimation condition which concerns on the actual measurement of the position estimation process. It is a figure which shows the evaluation result which concerns on the actual measurement of the position estimation process. It is a figure which shows the measurement condition of the implementation environment which concerns on the actual measurement of the distributed processing. It is a figure which shows the waveform of the received signal which concerns on the actual measurement of the distributed processing. It is a figure which shows the evaluation result which concerns on the actual measurement of the distributed processing. It is explanatory drawing explaining the position estimation process at the time of giving directivity. It is explanatory drawing explaining the position estimation process at the time of giving directivity in 2nd Embodiment. It is explanatory drawing explaining the position estimation process at the time of providing a plurality of transmitters 2 in the 2nd Embodiment. It is a screen view which shows an example of the mapping display screen which concerns on 3rd Embodiment. It is an internal block diagram which shows the main internal structure of the receiver which concerns on 3rd Embodiment.

(A) First Embodiment The first embodiment of the position estimation device, the position estimation program, and the position estimation method according to the present invention will be described in detail with reference to the drawings.

(A-1) Configuration of First Embodiment FIG. 2 is an explanatory diagram illustrating an environment for performing position estimation according to the first embodiment.

The environment shown in FIG. 2 illustrates the case where the GPS signal does not reach indoors. The transmitter 2 transmits, for example, ultrasonic waves, and the receiver 1 receives the ultrasonic waves transmitted by the transmitter 2. In this embodiment, the case where ultrasonic waves are used is illustrated, but the present invention is not limited to ultrasonic waves, and sound waves, radio waves, and the like may be used.

FIG. 2 illustrates a plan view of the room when viewed from above, but the environment may be a three-dimensional space. Further, although FIG. 2 shows one transmitter 2 and a receiver 1, a plurality of transmitters 2 and receivers 1 may be arranged. Further, at least the transmitter 2 may be movable.

There are a plurality of reflectors 5 in the environment of FIG. The reflector 5 is an object that reflects an ultrasonic signal from the transmitter 2, such as a wall in a room or an obstacle.

FIG. 2 illustrates an environment in which ultrasonic waves are not directly received by the receiver 1. That is, the case where the direct wave is blocked by the reflector 5 and only the reflected wave reflected by the reflector 5 arrives at the receiver 1 is illustrated.

FIG. 3 is an internal configuration diagram showing an internal configuration of the transmitter 2 according to the first embodiment.

In FIG. 3, the transmitter 2 transmits a pulse generator 21 that generates a pulse signal having a predetermined frequency (for example, a frequency of 20 [kHz] or higher), and a pulse signal as an ultrasonic wave generated by the pulse generator 21. It has a transmitter 22 and a transmitter 22. As the transmission unit 22, one having an ultrasonic element or the like can be applied.

In this embodiment, the case where the transmitter 2 transmits ultrasonic waves is illustrated. However, the transmitter 2 may transmit sound waves in combination with a speaker, or the transmitter 2 may transmit radio waves in combination with a high frequency device.

FIG. 1 is a configuration diagram showing an internal configuration of the receiver 1 according to the first embodiment.

In FIG. 1, the receiver 1 includes at least two systems of reception processing units 11 (11-1, 11-2), a correlation value detection unit 12, a time difference detection unit 13, an arrival angle estimation unit 14, a position estimation unit 15, and an electric power. It has a detection unit 16. Further, each reception processing unit 11 (11-1, 11-2) has a reception unit 111, a signal amplifier 112, and a separation processing unit 113.

The separation processing unit 113, the correlation value detection unit 12, the time difference detection unit 13, the arrival angle estimation unit 14, the position estimation unit 15, and the power detection unit 16 may be implemented by, for example, a microcomputer. That is, various functions are realized by the CPU executing a processing program (position estimation program) stored in the ROM.

The receiver 1 estimates the arrival angle of each reflected wave based on the delay time of each incoming reflected wave, estimates the arrival path of each reflected wave using the ray tracing method, and transmits the ultrasonic wave (that is, that is). , The position of the transmitter 2) is estimated.

The receiver 1 can also receive the direct wave from the transmitter 2, and the position of the transmitter 2 can be estimated by using the direct wave. However, in this embodiment, only the reflected wave is used. The case of estimating the position of the transmitter 2 will be described.

The receiving unit 111 receives the incoming ultrasonic waves and gives the amplifier 112 a signal converted into an electric signal by the ultrasonic element.

The signal amplifier 112 amplifies the received signal from the receiving unit 111 and gives it to the separation processing unit 113.

The separation processing unit 113 performs separation processing of the direct wave and the reflected wave, or a plurality of transmitters 2 based on the received signal amplified by the signal amplifier 112. For example, the received signal may include a direct wave signal component and a reflected wave signal component. The separation processing unit 113 separates the signal component of the reflected wave from the received signal.

The receiver 1 recognizes the direct wave signal component by holding a preset direct wave signal component or holding the direct wave signal component by communicating with the transmitter 2. Can be done.

The correlation value detection unit 12 correlates the received signals received by the reception processing unit 11-1 and the reception processing unit 11-2 based on the separation results of the signal processing units 11-1 and 11-2. Is. As a result, the signal wave received by the reception processing unit 11-1 and the reception processing unit 11-2 can be detected.

The time difference detection unit 13 has the reflected wave received by the receiving unit 111 of the receiving processing unit 11-1 and the reflected wave received by the receiving unit 111 of the receiving processing unit 11-2 based on the correlation result of the correlation value detecting unit 12. It detects the time difference (delay time) between and.

The arrival angle estimation unit 14 estimates the arrival angle of each reflected wave path (hereinafter, also referred to as “ray”) based on the time difference of the reflected waves detected by the detection unit 13.

The power detection unit 16 detects the power value of the correlation value of each ray based on the correlation value obtained by the correlation value detection unit 12.

The position estimation unit 15 utilizes the arrival angle of the arrival path of each reflected wave estimated by the arrival angle estimation unit 14 and a preset environment model (arrangement model of objects arranged in the vicinity). The position of the transmitter 2 is estimated by finding the intersection of the paths (each ray) of each reflected wave.

The position estimation unit 15 has a reflection number counting unit 151 that counts the number of reflections of each ray.

Hereinafter, the separation process, the correlation value detection process, the time difference detection process, the arrival angle estimation process, and the position estimation process in the receiver 1 according to the first embodiment will be described with reference to the drawings.

(A-2) Separation processing In the position estimation technology that uses radio waves and sound waves, the signal component of the direct wave and the signal component of the reflected wave may overlap when the path difference between the direct wave and the reflected wave is small. , It is necessary to separate the signal components. Further, when the receiver 1 receives the signals from the plurality of transmitters 2, each signal may be superimposed, and even in that case, it is necessary to separate and process each signal for each transmitter 2.

The separation processing of each signal when ultrasonic waves are used in the separation processing unit 113 will be described below.

When ultrasonic waves are used, the reflected wave may not be detected due to the reverberation phenomenon of the ultrasonic vibrator.

The reverberation is a vibration reverberation generated while the ultrasonic vibrator is performing damped vibration. The reverberation takes a time exceeding the transmission signal time from the start of driving to the attenuation.

FIG. 4 is a diagram showing a waveform (transmitted signal) of ultrasonic waves transmitted by the transmitter 2 and a waveform of a received signal received by the receiver 1 in the first embodiment.

In FIG. 4, the horizontal axis is time, and the transmission signal is based on the transmission time. As shown in FIG. 4, it can be seen that the drive time of the received signal is longer due to the reverberation with respect to the drive time of the transmission signal.

For example, in an environment where a direct wave and a reflected wave can be observed, when the path difference between the direct wave and the reflected wave is small, the reflected wave arrives during the reverberation time of the direct wave, and the signal component of the reflected wave is a direct wave signal. It is conceivable that the signal component of the reflected wave cannot be detected because it is buried in the component.

FIG. 5 is an explanatory diagram illustrating a case where the reflected wave is buried during the reverberation time of the direct wave.

FIG. 5A shows a case where the received signal includes only a direct wave, and FIG. 5B shows a case where the received signal includes a direct wave and a reflected wave.

As shown in FIG. 5 (B), the reflected wave should be detected at 7.0 [ms] from the transmission time due to the positional relationship of "transmission point-reflection point-reception point", but the signal component of the reflected wave (Waveform) is buried in the signal component (waveform) of the direct wave, and the signal component of the reflected wave cannot be detected.

The same phenomenon is observed when the received signal contains only the reflected wave, and when the path difference between the reflected waves is small, the reflected wave of the second arrival arrives during the reverberation time of the first reflected wave and the second arrival arrives. The reflected wave may not be separated.

As a method of separating the reflected wave, it is conceivable to hold the waveform data of the direct wave in advance and subtract the data of the direct wave from the received signal to extract the reflected wave.

FIG. 6 is a flowchart showing a separation process for separating the reflected wave by the separation process unit 113 according to the first embodiment.

The separation processing unit 113 holds the waveform data of the direct wave (S11). The direct wave waveform data may be set in advance, or the direct wave waveform data may be exchanged and held by the receiver 1 by communication between the transmitter 2 and the receiver 1. ..

When the separation processing unit 113 acquires the received signal from the signal processing unit 112, the separation processing unit 113 correlates the received signal data with the waveform data of the direct wave, and detects the position where the maximum correlation value is the head position of the direct wave. (S12). When the separation processing unit 113 detects the head position of the direct wave, it subtracts the waveform data of the direct wave from the received signal data (S13) and extracts the waveform data of the reflected wave (S14).

As described above, the separation processing unit 113 extracts the reflected wave data by attenuating the direct wave data with respect to the received signal from the head position of the estimated direct wave waveform. This process is also effective when separating only the reflected wave.

As a method of separating the reflected wave, in addition to subtracting the direct wave, the transmitted waveform is subjected to modulation processing such as code diffusion, and the reflected wave is separated from the direct wave by correlating with the corresponding code at the time of reception. It is possible.

FIG. 7 is a diagram showing a signal waveform example of the ultrasonic signal according to the first embodiment. FIG. 8 is a diagram showing a state when the reflected wave is out of phase with the direct wave.

FIG. 7 shows a case where the ultrasonic transmission signal is, for example, 40 [kHz]. A transmission signal as shown in FIG. 7 is transmitted from the transmitter 2, and as shown in FIG. 8, a reflected wave that is out of phase with the direct wave may be buried in the direct wave and received by the receiver 1. ..

The reflected wave is out of phase with the direct wave, but since the signal waveform of the reflected wave is close to the signal waveform of the direct wave, the correlation value between the signal waveform of the reflected wave and the waveform data of the direct wave is large. Therefore, there is a problem that it is difficult to separate the reflected wave.

On the other hand, as shown below, the reflected wave can be separated by performing code expansion modulation on the ultrasonic signal.

FIG. 9 is an explanatory diagram illustrating code diffusion modulation of an ultrasonic signal. FIG. 10 is a diagram showing waveforms of a direct wave and a reflected wave when code diffusion modulation is performed.

As shown in FIG. 9, when code "0" and code "1" are alternately applied to the signal waveform illustrated in FIG. 9 (A) at a predetermined cycle, the signal waveform illustrated in FIG. 9 (B) is obtained. .. The phase of the signal in the section multiplied by code "1" remains the same, but the frequency of the signal in the section multiplied by code "0" is changed.

As shown in FIG. 10, by applying a code to the signal waveform, even if the reflected wave is out of phase with respect to the direct wave, the signal waveform of the reflected wave does not resemble the signal waveform of the direct wave. Since the correlation value between the signal waveform of the above and the waveform data of the direct wave becomes small, the reflected wave can be separated.

In this case, when the transmitter 2 applies the code, the receiver 1 needs to share the code, and the separation processing unit 113 correlates with the waveform modulated by the code used by the transmitter 2. Take. For example, the transmitter 2 and the receiver 1 can share a code by exchanging control information including the code information used by the transmitter 2 between the transmitter 2 and the receiver 1.

As a modified embodiment using the code diffusion modulation of the ultrasonic signal, the code used by each transmitter 2 may be assigned to each transmitter 2. As a result, since the code used by each transmitter 2 is different, each transmitter 2 can be modulated with a unique code. As a result, the receiver 1 can specify the transmitter 2 which is the transmission destination of the received signal based on the code, and demodulates using the code used by each transmitter 2.

(A-3) Correlation value detection process and time difference detection process FIG. 11 is an explanatory diagram illustrating the correlation value detection process and the time difference detection process according to the first embodiment.

The correlation value detection unit 12 and the time difference detection unit 13 detect the correlation value and the time difference using a plurality of received waveforms separated by each separation processing unit 113.

The correlation value detection unit 12 acquires the signal separated by each separation processing unit 113. That is, the waveform data of the direct wave is subtracted by each separation processing unit 113, and the received signal obtained by subtracting the waveform data of the direct wave from the direct wave and the reflected wave is acquired.

The correlation value detection unit 12 shifts each received waveform from the current head position and detects mutual correlation values. The peak (maximum value) of the cross-correlation value is detected from the beginning. Then, the time difference detection processing unit 13 detects the time at which the maximum value of the cross-correlation value is reached from the head position of one signal waveform as the time difference of the plurality of received waveforms.

(A-4) Arrival Angle Estimating Process FIG. 12 is an explanatory diagram illustrating a basic concept of the arrival angle estimation processing according to the first embodiment.

The arrival angle estimation unit 14 estimates the arrival direction of the reflected wave by using, for example, the MUSIC method, which is a known technique, or a means such as estimating the arrival direction using the arrival time difference of a plurality of receivers.

FIG. 12 shows an example in which the receiving units 111 of the receiving processing units 11-1 and 11-2 are arranged in a linear vector as array reception.

Let τ be the arrival time difference between the two receiving units 111, c be the arrival speed of the ultrasonic signal, d be the distance length between the two receiving units 111, and θ be the arrival direction (angle) of the ultrasonic signal. 1) holds.

As shown in FIG. 12, when two receiving units 111 are separated by a distance length d and an ultrasonic signal arrives at each receiving unit 111 from the direction of the angle θ, the ultrasonic signal in each receiving unit 111 The arrival time is different. That is, the ultrasonic signal arrives at one receiving unit 111, and the ultrasonic signal arrives at the other receiving unit 111 after the arrival time difference (delay time) τ. Equation (1) is a relational expression for deriving the arrival direction θ from the relation illustrated in FIG.

When the equation (1) is modified, the arrival direction (angle) θ becomes the equation (2).

FIG. 13 is an explanatory diagram illustrating an arrival direction estimation process according to the first embodiment.

As shown in FIG. 13, the ultrasonic signal from the transmitter 2 arrives at each receiving unit 111 as a direct wave, or arrives at each receiving unit 111 as a reflected wave reflected by the reflector 5.

The arrival angle estimation unit 14 estimates the arrival direction of each signal waveform according to the equation (2), using the time difference of each received waveform (that is, direct wave and reflected wave) detected by the time difference detection unit 13 as the arrival time difference τ. ..

Here, in the equation (2), the distance length d between the two receiving units 111 and the arrival speed c of the ultrasonic signal can be set in advance. Therefore, if the arrival time difference τ of each signal waveform is known, the arrival direction of each signal waveform can be estimated.

Although FIG. 13 illustrates the case where the direct wave arrives, the arrival direction of the reflected wave can be similarly estimated when only the reflected wave arrives at the receiver 1.

(A-5) Position estimation process (A-5-1) Basic concept FIG. 14 is a flowchart showing a position estimation process according to the first embodiment. FIG. 15 is an explanatory diagram illustrating the position estimation process according to the first embodiment.

In FIG. 14, the position estimation unit 15 sets the environment model related to the position estimation (S21), and sets the position of the receiver 1 in the environment model (S22).

The environment model is, for example, an indoor floor model (length, width, height), a two-dimensional space including the position, shape, size (length, width, height) of the reflector 5, and a three-dimensional space model. be. The environment model may be set in the receiver 1 in advance, or may be changed as appropriate. For example, if there is a movable object in the room, the positional relationship of the reflector 5 can be changed. In that case, the contents of the environmental model may be changed. In any case, the indoor floor model at the time of position estimation and the model showing the positional relationship of the reflector 15 are used.

Further, the environment model is composed of two-dimensional coordinates and three-dimensional coordinates, and the position of the receiver 1 is set with respect to the reference point. Thereby, the position of the receiver 1 in the set environment model can be determined.

The position estimation unit 15 sets the arrival direction θ of each signal wave estimated by the arrival angle estimation unit 14 with the position of the receiver 1 in the environment model as a base point (S23), and uses the ray tracing method to set each signal. Track the path of arrival of the wave (S24). The ray tracing method is a process of finding the intersection of rays from the arrival direction of each ray and data such as a floor model and obstacles in the room.

The position estimation unit 15 tracks the arrival path of each signal wave, and estimates the intersection of each line (ray) as a transmission point (that is, the position of the transmitter 2) (S25).

FIG. 16 is an explanatory diagram illustrating a transmission point estimation process using the ray tracing method.

In FIG. 16, for ease of explanation, a case where two rays (rays 3 and 4) are traced from the base point (position of the receiver 1) is illustrated.

In FIG. 16A, the position estimation unit 15 extends the ray 3 from the base point 1 on an extension line in the arrival direction. At this time, the point where the ray 3 collides with the reflector 5 is defined as the “intersection point 31”. When the ray 3 hits the reflector 5, the position estimation unit 15 obtains an angle (reflection angle) with respect to the reflector 5, and extends the ray 3 from the "intersection point 31" toward an incident angle equal to the reflection angle.

Similarly, as shown in FIG. 16B, the position estimation unit 15 extends the ray 4 from the base point 1 on an extension line in the arrival direction. Then, the point where the ray 3 and the ray 4 intersect can be estimated as the position of the transmission point.

In the above, the position estimation process in two dimensions on the XY horizontal plane has been described, but as shown in FIG. 17, the position estimation in three dimensions may be performed. In this case, the arrival angle estimation unit 14 estimates the direction of the vertical angle in addition to the estimation of the arrival angle in the horizontal direction, and estimates the arrival direction in three dimensions. Then, the position estimation unit 15 may perform ray tracing based on the three-dimensional arrival direction of each signal wave, and perform position estimation in three dimensions.

(A-5-2) Position estimation process when there are a plurality of intersections FIG. 18 is an explanatory diagram illustrating a position estimation process when there are a plurality of intersections.

As shown in FIG. 18, when the arrival paths (rays) of a plurality of signal waves are traced by the ray tracing method, when a plurality of reflection times occur, a plurality of intersections (intersection 61, intersection 62 in FIG. 18) May occur. That is, a plurality of transmission point candidates will be generated. In this case, the problem is which of the plurality of intersections (intersection 61, intersection 62) is estimated as the transmission point.

In this embodiment, the position estimation unit 15 has a reflection count counting unit 151 that counts the number of reflections of each ray, and the reflection count counting unit 151 limits the creation of each ray based on the reflection count of each ray. You may try to do it.

FIG. 19 is a flowchart showing a process of limiting the number of reflections by the reflection number counting unit 151.

In FIG. 19, first, the reflection number counting unit 151 initializes the reflection number of each ray (S31). Then, the position estimation unit 15 creates each ray in the environment model by the ray tracing method. At this time, the reflection count unit 151 monitors whether or not each ray reflects with the reflector 5 (S32), and if each ray reflects on the reflector 5, proceeds to S33.

The reflection count counting unit 151 has a threshold value for limiting the generation of each ray, compares the reflection count of each ray with the threshold value, and determines whether or not the reflection count of each ray is equal to or less than the threshold value. (S33).

At this time, if the number of reflections of each ray is equal to or less than the threshold value, the number of reflections of the ray is incremented (that is, "1" is added) (S34) to create a ray whose incident angle is equal to the reflection angle (S35).

On the other hand, if the number of reflections of each ray is not less than or equal to the threshold value, the creation of the ray is terminated.

In this way, by limiting the creation of each ray based on the number of reflections of each ray, the number of intersections of the plurality of rays can be set to one point.

As the number of reflections of the ray increases, the path distance increases, and as the path distance increases, the signal becomes inaccurate due to attenuation. In this embodiment, by providing the reflection number counting unit 151, the number of reflections of each ray at the time of ray tracing is limited, the intersection 1 can be set to one point, and the transmission point can be determined.

In this embodiment, the case of limiting the creation of rays based on the number of reflections has been illustrated, but the present invention is not limited to this.

For example, a threshold may be used to limit the length of each ray created by the ray tracing method. Also by this method, the number of intersections of each ray can be limited by limiting the length of the rays, and the transmission point can be set to one point. Further, for example, when the first intersection of a plurality of rays occurs, the intersection may be estimated as the transmission point. Further, when there are three or more rays, the intersection of the three or more rays may be estimated as a transmission point.

(A-5-3) Selection of highly reliable ray In the non-line-of-sight environment where the direct wave does not arrive, the case where the position estimation process is performed using only the reflected wave has been described.

However, when the transmitter 2 moves, not only the non-line-of-sight environment but also the line-of-sight and non-line-of-sight environments may change sequentially. In the environment within the line of sight, the received signal in the receiver 1 is a mixture of direct wave / reflected wave / diffracted wave.

Therefore, in this embodiment, the position estimation unit 15 selects a signal wave having a high power value based on the power value of the signal wave detected by the power detection unit 16, and ray-traces using the arrival angle of the signal wave. do. This makes it possible to select a highly reliable ray and estimate the transmission point.

FIG. 20 is a flowchart showing a process of selecting a highly reliable signal wave from a plurality of signal waves in the first embodiment.

First, as described above, the correlation value detection unit 12 correlates each signal wave (received wave) received by each of the receiving units 111 of the receiving processing unit 11-1 and the receiving processing unit 11-2, and receives the received wave. Is detected.

FIG. 21 is a diagram showing a reception wave received by the reception unit 111 of the reception processing unit 11-1 and a reception wave received by the reception unit 111 of the reception processing unit 11-2. FIG. 21 shows a case where a direct wave, two reflected waves 1 and a reflected wave 2 are detected.

The power detection unit 16 of each waveform is based on the time relationship between the waveform of each signal wave of the reception unit 111 of the reception processing unit 11-1 and the waveform of each signal wave of the reception unit 111 of the reception processing unit 11-2. Make an association. For example, in FIG. 21, three signal waves are detected in the received waveforms of the received wave received by the receiving unit 111 of the receiving processing unit 11-1 and the received wave received by the receiving unit 111 of the receiving processing unit 11-2. Therefore, it is estimated that the first signal wave is a direct wave, the next signal wave is a reflected wave 1, and the last signal wave is a reflected wave 2. Further, the power detection unit 16 detects the power value (amplitude value) of each signal wave (direct wave, reflected wave 1, reflected wave 2). The power value may be the average power value of the waveform section or the maximum power value.

In FIG. 20, the position estimation unit 15 acquires the power value of each signal wave from the power detection unit 16 (S41), compares the power value of each signal wave with a preset threshold value, and the power value exceeds the threshold value. Whether or not it is determined (S42). Then, when the power value exceeds the threshold value, the position estimation unit 15 selects the signal wave (S43), and when the power value is equal to or less than the threshold value, the position estimation unit 15 does not use the signal wave (S44).

The position estimation unit 15 creates a ray by the ray tracing method using the arrival angle of the selected signal wave, and tracks the arrival direction of the signal wave (S45). Then, the intersection of each ray is estimated as a transmission point (S46).

In the above, the case where the power value of the signal wave is used as an index for selecting the ray has been illustrated, but the present invention is not limited to this. For example, it may be an arrival route to the intersection of each ray.

(A-6) Example of position estimation
[Confirmation of position estimation accuracy]
An example in which the position estimation accuracy using only the reflected wave is actually measured in a non-line-of-sight environment will be described.

In FIG. 22, a speaker was used as the transmitter 2. An array with two microphones was used as the receiver 1. The distance between the two microphones was set to 200 [cm]. The midpoint between the two microphones is set as the origin [0,0].

The arrival angle is estimated from the two microphones (origins), and the arrival angles of the two types of reflected waves (reflected wave 1 and reflected wave 2) are estimated.

If you follow the trace of each reflected wave, it will hit the reflector, and if you follow the trace of the incident wave with the incident angle and the reflection angle set equal, you will connect the intersection. The intersection is set as the estimated position of the speaker.

FIG. 23 is an evaluation result. In FIG. 23, the "coordinates of the expected position" of the transmission point were [-200 cm, -3.5 cm], while the "coordinates of the estimated position" of the transmission point were [-208 cm, -6.9 cm]. The position estimation error of the transmission point was 8.7 [cm], and highly accurate position estimation was possible.

[Confirmation of separation process]
In position estimation using ultrasonic waves, the waveform data of the direct wave is held in advance, and the reflected wave is subtracted from the received signal for the waveform in which the reflected wave is buried in the reverberation of the direct wave. We confirmed the accuracy of the method of extracting.

FIG. 24 shows the measurement conditions of the implementation environment. As shown in FIG. 24, the distance between the speaker and the microphone was set to 200 [cm]. In this case, since the path difference between the direct wave and the reflected wave is small, the reflected wave is buried in the reverberation portion of the direct wave.

Here, the waveform data of the direct wave was held in advance, the received signal was correlated with the direct wave, and the held direct wave was subtracted from the position where the maximum value was obtained.

FIG. 25 shows a waveform of the received signal and a waveform obtained by extracting the reflected wave by directly subtracting the wave data from the received signal. As shown in FIG. 25, the second peak of the received signal is the reflected wave, but it is buried in the direct wave and the head position cannot be known. On the other hand, in the waveform after subtraction, the head of the extracted reflected wave can be clearly seen.

FIG. 26 is an evaluation result. As shown in FIG. 26, the expected path difference between the direct wave and the reflected wave was 28.25 [cm], but the estimated path difference between the direct wave and the reflected wave was 26.27 [cm]. The estimation error was 2 [cm], which enabled highly accurate route estimation.

(A-7) Effect of First Embodiment As described above, according to the first embodiment, it is possible to estimate the non-line-of-sight environment position by using only the reflected wave.

Further, according to the first embodiment, it is possible to perform accurate position estimation by performing ray tracing while performing separation processing on the received signal having a small path difference.

Further, according to the first embodiment, it is possible to perform more accurate position estimation by selecting a ray having high reliability in terms of reception level or the like even in a line-of-sight / non-line-of-sight environment.

(B) Second Embodiment Next, a second embodiment of the position estimation device, the position estimation program, and the position estimation method according to the present invention will be described with reference to the drawings.

The second embodiment differs from the first embodiment in that either or both of the transmitter 2 and the receiver 1 are provided with directivity.

Other than that, it is the same as that of the first embodiment, and the receiver 1 according to the second embodiment has the internal configuration shown in FIG. 1 of the first embodiment, and the transmitter according to the second embodiment has the internal configuration. The machine 2 has the internal configuration shown in FIG. 3 of the first embodiment.

The transmitter 2 has directivity to transmit the ultrasonic signal, and the receiver 1 has directivity to receive the ultrasonic signal, so that the receiver 1 has higher accuracy in the position of the transmitter 2. Can be estimated.

Since the existing technology can be widely applied to the directivity technology in which the transmitter 2 and the receiver 1 have directivity for radio waves and ultrasonic signals, detailed description thereof will be omitted here. In particular, as a directivity technique related to transmission of an ultrasonic signal, it is possible to further enhance the directivity by a mechanical means such as a horn.

FIG. 27 is an explanatory diagram illustrating a position estimation process when directivity is provided.

27 (A) shows the case where the receiver 1 is within the directivity range of the transmitter 2, and FIG. 27 (B) shows the case where the receiver 1 is within the directivity range of the transmitter 2. Indicates the case where it exists outside.

Conventionally, there is a problem that it is difficult for the receiver 1 to estimate the position of the transmitter 2 in a non-line-of-sight environment.

For example, assume that the transmitter 2 is movable. As shown in FIG. 27 (A), when the receiver 1 is within the directivity range of the transmitter 2, the receiver 1 can directly receive the wave, so that the transmitter 2 The position of can be estimated.

However, as shown in FIG. 27 (B), when the receiver 1 is out of the directivity range of the transmitter 2, the receiver 1 cannot receive the direct wave and cannot estimate the position of the transmitter 2. Sometimes.

Conventionally, there is also a method of linking the receiver and the transmitter to direct the antenna / speaker of the transmitter toward the receiver side. However, when the receiver and the transmitter are linked, it becomes a large-scale system and the cost becomes high.

Since the present invention can perform position estimation using only the reflected wave outside the line of sight, the transmitter 2 and the receiver even if the transmitter 2 moves and the receiver 1 is out of the directivity range of the transmitter 2. The receiver 1 can estimate the position of the transmitter 1 without the machine 1 following the directivity.

FIG. 28 is an explanatory diagram illustrating a position estimation process in the case of giving directivity in the second embodiment.

As shown in FIG. 28A, when the receiver 1 is within the directivity range of the transmitter 2 (within the line of sight), the receiver 1 can naturally estimate the position of the transmitter 2.

Further, as shown in FIG. 28 (B), even when the receiver 1 is out of the directivity range of the transmitter 2 and the line of sight is out of sight, the reflected wave reflected by the reflector 5 such as the surrounding wall is the receiver 1. The receiver 1 can estimate the position of the transmitter 2 using only the reflected wave.

FIG. 29 is an explanatory diagram illustrating a position estimation process when a plurality of transmitters 2 are provided in the second embodiment.

For example, by mounting a plurality of transmitters 2 having directivity on a device on the transmitting side, direct waves, reflected waves, and the like arrive at the receiver 1, so that position estimation can be performed more reliably.

As shown in FIG. 29 (A), when the receiver 1 exists within the directivity range of the transmitter 2, there is a possibility that the direct wave and the reflected wave reflected by the reflector 5 arrive at the receiver 1. be. Further, as shown in FIG. 29 (B), even when the transmitter 2 moves, there is a high possibility that the receiver 1 exists in the directivity range of another transmitter 2. Therefore, in this case as well, the direct wave When the reflected wave arrives at the receiver 1, the receiver 1 can perform position estimation.

In the second embodiment, the case where the transmitter 2 transmits the transmission signal with directivity is illustrated. However, of course, giving the receiver 1 directivity has the same effect.

Further, in the second embodiment, an example of a direct wave and a reflected wave is shown, but of course, a combination of various types of incoming waves including a diffracted wave has the same effect.

(C) Third Embodiment Next, a third embodiment of the position estimation device, the position estimation program, and the position estimation method according to the present invention will be described with reference to the drawings.

In the third embodiment, the receiver 1 has a function of mapping and displaying the estimated position of the transmitter 1.

FIG. 31 is an internal configuration diagram showing a main internal configuration of the receiver 1 according to the third embodiment. FIG. 30 is a screen view showing an example of a mapping display screen according to the third embodiment.

In FIG. 31, the receiver 1 according to the third embodiment has a display control unit 17 and a display unit 18 in addition to the components shown in FIG.

The display control unit 17 acquires the position estimation information estimated by the position estimation unit 15 and the data of the environment model, and maps and displays the position of the transmission point in the indoor environment based on the environment model.

The display unit 18 is, for example, a display unit such as a display, and displays a map screen including an estimated position of the transmitter 2 as illustrated in FIG. 30, based on mapping data from the display control unit 17.

If the position estimation information estimated by the position estimation unit 15 of the receiver 1 and the data of the environment model can be given to the display control unit 17, the display control unit 17 and the display unit 18 need not be mounted on the receiver 1. do not have. The display control unit 17 and the display unit 18 may be located at a location remote from the receiver 1 and display the position of the transmitter 1 at a position away from the receiver 1.

Further, the display control unit 17 and the display unit 18 may be connected to a plurality of receivers 1 so that the estimated positions of a large number of transmitters 1 may be mapped and displayed on one map.

According to the third embodiment, the estimated position estimated by the position estimation unit 15 can be mapped and displayed on a map based on the environment model used in the ray tracing.

Further, according to the third embodiment, the position of the transmitter 2, which cannot be seen due to an indoor wall or the like, can be accurately mapped and displayed on the map.

1 ... Receiver, 11 (11-1, 11-2) ... Reception processing unit, 12 ... Correlation value detection unit, 13 ... Time difference detection unit, 14 ... Arrival angle estimation unit, 15 ... Position estimation unit, 16 ... Power detection Unit, 17 ... Display control unit, 18 ... Display unit, 111 ... Receiver unit, 112 ... Signal amplifier, 113 ... Separation processing unit,
2 ... transmitter, 21 ... pulse generator, 22 ... transmitter.

Claims (7)

In a position estimation device that estimates the transmission position of a transmission wave including a signal diffusely modulated by the transmission side based on the reflected wave of the transmission wave.
Multiple receivers that capture incoming waves,
The diffusion-modulated signal wave included in each received signal is acquired from each of the above receiving units, and the each signal wave is correlated with the waveform data of the transmitted wave set in advance, and the correlation value is set to the maximum value. A plurality of separation processing units that separate the reflected wave contained in the received signal by subtracting the signal component of the direct wave from the received signal, with the position as the head position of the direct wave.
A time difference detection unit that cross-correlates each reflected wave separated by each of the separation processing units and detects the arrival time difference of each reflected wave that has arrived at each of the receiving units.
An arrival angle estimation unit that estimates the arrival angle of each reflected wave based on the arrival time difference of each reflected wave,
A position characterized by including a position estimation unit that tracks the arrival path of each reflected wave based on the arrival angle of each reflected wave and estimates the intersection of the arrival paths of each reflected wave as the transmission position of the transmitted wave. Estimator. The position estimation device according to claim 1, wherein the position estimation unit tracks the arrival path of each of the reflected waves by a ray tracing method using the environment model information related to the position estimation. The position estimation device according to claim 2, wherein the position estimation unit limits tracking of the arrival path of each reflected wave by the ray tracing method. The claim is characterized in that the position estimation unit counts the number of reflections reflected by the arrival path of each reflected wave on the reflector in the environment model information, and limits the tracking of the arrival path based on the number of reflections. 3. The position estimation device according to 3. It is equipped with a power detection unit that detects the power value of each of the above reflected wave components.
Any of claims 1 to 4, wherein the position estimation unit tracks the arrival path of the reflected wave whose power value exceeds the threshold value among the reflected wave components, and estimates the position of the transmission point. Position estimation device described in. In a position estimation program that estimates the transmission position of a transmission wave including a signal diffusely modulated by the transmission side based on the reflected wave of the transmission wave included in the arrival wave captured by each of a plurality of receivers.
Computer,
The diffusion-modulated signal wave included in each received signal is acquired from each of the above receiving units, and each signal wave component is correlated with the preset waveform data of the transmitted wave, and the correlation value becomes the maximum value. A plurality of separation processing units that separate the reflected wave contained in the received signal by subtracting the signal component of the direct wave from the received signal with the position as the head position of the direct wave.
A time difference detection unit that cross-correlates each reflected wave separated by each of the separation processing units and detects the arrival time difference of each reflected wave that has arrived at each of the receiving units.
An arrival angle estimation unit that estimates the arrival angle of each reflected wave based on the arrival time difference of each reflected wave,
The feature is that the arrival path of each reflected wave is tracked based on the arrival angle of each reflected wave, and the intersection of the arrival paths of each reflected wave functions as a position estimation unit that estimates the transmission position of the transmitted wave. Position estimation program to do. In a position estimation method in which the transmission position of a transmission wave including a signal diffusely modulated by the transmission side is estimated based on the reflected wave of the transmission wave.
Each of the multiple receivers captures the incoming wave and
Each of the plurality of separation processing units acquires the diffusion-modulated signal wave contained in each received signal from each of the received units, and correlates each signal wave component with the preset waveform data of the transmitted wave. The position where the correlation value becomes the maximum value is set as the head position of the direct wave, the signal component of the direct wave is subtracted from the received signal, and the reflected wave contained in the received signal is separated.
The time difference detection unit takes a cross-correlation of each reflected wave separated by each of the above separation processing units, and detects the arrival time difference of each reflected wave that has arrived at each of the above receiving units.
The arrival angle estimation unit estimates the arrival angle of each reflected wave based on the arrival time difference of each of the reflected waves.
The position estimation unit tracks the arrival path of each reflected wave based on the arrival angle of each of the reflected waves, and estimates the intersection of the arrival paths of each reflected wave as the transmission position of the transmitted wave. Method.

Images