JP5716219B1 - Position estimation method and position estimation apparatus - Google Patents

Abstract

There is provided a method capable of estimating a wave source position in a short time without requiring a receiver at a plurality of points. A receiver J installed between a seawater surface W1 and a seafloor W2 receives a direct wave D directly reaching the receiver J from a wave source H or reflected once by the seawater surface W1. The first reflected wave R1 that has reached the wave device J and the second reflected wave R2 that has been reflected once by the sea floor W2 and reached the wave receiver J are received. Then, the expression of the first hyperbola S1 focusing on the wave source H and the mirror image H1 of the wave source H with respect to the first boundary surface, or the second hyperbola S2 focusing on the mirror image H2 of the wave source H with respect to the wave source H and the sea bottom W2. An expression is required. Then, by combining the expression of the first hyperbola S1 and the expression of the second hyperbola S2, the coordinates of the focal point common to the first hyperbola S1 and the second hyperbola S2, which are the coordinates of the wave source H, are obtained. [Selection] Figure 1

Description

  The present invention relates to a method and apparatus for estimating the position of a pulse wave source.

  Since the attenuation of electromagnetic waves is large in water, sound waves are generally used to detect underwater objects. As a method for detecting an underwater object using sound waves, there are a method called active sonar and a method called passive sonar. Active sonar detects the echo sound reflected from the object by transmitting the sound from the wave source, and seeks the distance and direction to the object, but it exposes its existence to make its own sound. become. On the other hand, passive sonar detects the radiated sound of an underwater object and does not emit sound itself, so it can detect an underwater object in secret. However, with passive sonar, it is easy to determine the orientation of an object, but in order to determine the distance to the object, complicated calculations such as target motion analysis and matched field processing are required. In the target motion analysis, the distance to the object can be estimated by continuous radiated sound, but the distance to the object cannot be obtained by temporary transient sound. In addition, it is necessary for the matched field processing to grasp the marine environment in advance, but it is difficult to create a database of complex characteristics of the marine environment that changes in time and space.

  As a method for obtaining a distance to an object with a temporary transient sound, a method using a propagation time difference of a sound wave has been studied. As such a method, there is a method called a brute force method disclosed in Non-Patent Document 1. Hereinafter, the brute force method will be described with reference to FIGS. 7 and 8.

  In the round robin method, as shown in FIG. 7A, the receiver j receives the transient sound generated by the actual target h, and directly reaches the receiver j without being reflected from the actual target h. The difference (1), (2) between the propagation time of the direct wave Dh and the propagation times of the reflected waves Rh1, Rh2 reflected by the seawater surface w1 and the seafloor w2 and reaching the receiver j is measured ( FIG. 8 (a)). Then, as shown in FIG. 7B, when the range in which the actual target h is assumed to be gridded and the temporary target k on each grid point generates a transient sound, the receiver The difference (3), (4) between the propagation time of the direct wave Dk that directly reaches j and the propagation time of the reflected waves Rk1 and Rk2 that are reflected by the seawater surface w1 and the seafloor w2 and reach the receiver j Are calculated brute force (for each grid point) (FIG. 8B). Then, the difference between the propagation time difference (3), (4) calculated for each temporary target k (each grid point) and the propagation time difference (1), (2) measured for the actual target h is calculated, Position information of the temporary target k that minimizes the difference (depth of the temporary target, distance between the temporary target and the receiver) is acquired as information indicating the position of the actual target h.

  Further, Patent Documents 1 and 2 disclose methods for estimating the position of a wave source based on a difference in propagation paths. In the methods of Patent Documents 1 and 2, a plurality of acoustic sensors are installed at different positions, and each acoustic sensor receives a direct wave from a wave source. Then, the propagation time difference between the direct waves received by any two acoustic sensors is calculated, and a hyperbola in which the propagation time difference between the two acoustic sensors is constant is obtained. This hyperbola is obtained for each set of two arbitrary acoustic sensors, and the intersection of the hyperbola obtained by two or more sets is estimated as the position of the wave source.

JP 2000-121719 A JP-A-11-326489

Symposium on Defense Technology and Reverse Search for Sonars Mounted on Underwater Unmanned Vehicles 2009

  However, in the brute force method, the number of grid points increases when the range (depth and distance) in which the actual target h is assumed to be large is large or when the grid step size is small. For this reason, it takes a long time to calculate the propagation time differences (3) and (4) for each lattice point. There are probabilistic solutions such as the Simulated Annealing method and the Genetic Algorism method as methods to improve this problem, but these methods cannot be said to be a method of searching for a solution reliably.

  Moreover, in the methods disclosed in Patent Documents 1 and 2, it is necessary to provide acoustic sensors at a plurality of points in order to obtain the wave source position.

  An object of this invention is to provide the method and apparatus which can estimate a wave source position in a short time, without providing a receiver in several points.

  In order to achieve the above object, a position estimation method according to a first aspect of the present invention is a method for estimating a position of a wave source that emits a pulse wave from between a first boundary surface and a second boundary surface. Receiving a pulse wave radiated from the wave source to a receiver installed between the first boundary surface and the second boundary surface, and reaching the receiver directly from the wave source; The arrival time of the direct wave, the arrival time of the first reflected wave that is reflected once at the first boundary surface and reaches the receiver, and the arrival time of the first reflected wave that is reflected once at the second boundary surface and reaches the receiver Based on the arrival time specifying step for specifying the arrival time of the second reflected wave and the arrival time of the direct wave and the arrival time of the first reflected wave, the propagation path difference between the direct wave and the first reflected wave is determined. Based on the arrival time of the direct wave and the arrival time of the second reflected wave. Based on the path difference calculating step for calculating the propagation path difference between the direct wave and the second reflected wave, the propagation path difference between the direct wave and the first reflected wave, and the coordinates of the receiver. A hyperbola passing through a waver, wherein a formula of a first hyperbola focusing on the wave source and a mirror image of the wave source with respect to the first boundary surface is obtained, and a propagation path difference between the direct wave and the second reflected wave And a hyperbola that passes through the receiver based on the coordinates of the receiver and obtains a formula of a second hyperbola that focuses on the wave source and a mirror image of the wave source with respect to the second boundary surface. The focal coordinate calculation for obtaining the common focal point coordinates of the first hyperbola and the second hyperbola as the coordinates of the wave source by combining the obtaining step and the first hyperbola equation and the second hyperbola equation Steps.

  A position estimation method according to a second aspect of the present invention is a method for estimating a position of a wave source that emits a pulse wave from between a first boundary surface and a second boundary surface, wherein the first boundary surface A receiving step for receiving a pulse wave radiated from the wave source to a receiver installed between a surface and the second boundary surface; and an arrival time of a direct wave that has directly reached the receiver from the wave source , The arrival time of the first reflected wave that is reflected once at the first boundary surface and reaches the receiver, and the second reflected wave that is reflected once at the second boundary surface and reaches the receiver Based on the arrival time specifying step for specifying the arrival time of the direct wave and the arrival time of the direct wave and the arrival time of the first reflected wave, a propagation path difference between the direct wave and the first reflected wave is calculated, Based on the arrival time of the direct wave and the arrival time of the second reflected wave, the direct wave and the second wave It is a hyperbola that passes through the wave source based on a path difference calculating step for calculating a propagation path difference with a wave, a propagation path difference between the direct wave and the first reflected wave, and coordinates of the receiver. Then, a first hyperbolic equation focusing on the receiver and a mirror image of the receiver with respect to the first boundary surface is obtained, a propagation path difference between the direct wave and the second reflected wave, and the receiver A hyperbola acquisition step for obtaining a hyperbola expression passing through the wave source based on the coordinates of the waver, the focus being on the wave receiver and a mirror image of the wave receiver with respect to the second boundary surface; And an intersection coordinate calculation step of obtaining the coordinates of the intersection of the first hyperbola and the second hyperbola, which are the coordinates of the wave source, by combining the expression of the first hyperbola and the expression of the second hyperbola.

  Moreover, in the position estimation method according to the first and second aspects of the present invention, the wave source includes the pulse wave from between the sea surface as the first boundary surface and the sea surface as the second boundary surface. The receiver is provided with a pressure sensor capable of measuring the water pressure at the position of the receiver, and based on the water pressure measured by the pressure sensor, A receiver coordinate calculation step for obtaining coordinates, and in the hyperbola acquisition step, the first hyperbola and the second hyperbola are used by using the coordinates of the receiver calculated in the receiver coordinate calculation step. Is obtained.

  A position estimation apparatus according to a third aspect of the present invention is an apparatus for estimating a position of a wave source that emits a pulse wave from between a first boundary surface and a second boundary surface, wherein the first boundary A receiver installed between a surface and the second boundary surface for receiving a pulse wave radiated from the wave source, and an arrival time of a direct wave that has directly reached the receiver from the wave source, The arrival time of the first reflected wave that is reflected once at one boundary surface and reaches the receiver, and the arrival time of the second reflected wave that is reflected once at the second boundary surface and reaches the receiver A propagation time difference between the direct wave and the first reflected wave is calculated based on the arrival time specifying unit for specifying the arrival time and the arrival time of the direct wave and the arrival time of the first reflected wave; Based on the arrival time and the arrival time of the second reflected wave, the propagation path difference between the direct wave and the second reflected wave is calculated. A path difference calculation unit to be output, a propagation path difference between the direct wave and the first reflected wave, and a hyperbola passing through the receiver based on the coordinates of the receiver, the wave source and the wave A first hyperbola formula focusing on the mirror image of the wave source with respect to the first boundary surface is obtained, and based on the propagation path difference between the direct wave and the second reflected wave, and the coordinates of the receiver. A hyperbola that passes through a waver, and that obtains a second hyperbola expression that focuses on the wave source and a mirror image of the wave source with respect to the second boundary surface; and the first hyperbola expression and the second hyperbola And a focal coordinate calculation unit that obtains the coordinates of the focal point common to the first hyperbola and the second hyperbola, which are the coordinates of the wave source, by combining the equations of the hyperbola.

  A position estimation apparatus according to a fourth aspect of the present invention is an apparatus for estimating the position of a wave source that emits a pulse wave from between a first boundary surface and a second boundary surface, wherein the first boundary surface A receiver installed between a surface and the second boundary surface for receiving a pulse wave radiated from the wave source, and an arrival time of a direct wave that has directly reached the receiver from the wave source, The arrival time of the first reflected wave that is reflected once at one boundary surface and reaches the receiver, and the arrival time of the second reflected wave that is reflected once at the second boundary surface and reaches the receiver A propagation time difference between the direct wave and the first reflected wave is calculated based on the arrival time specifying unit for specifying the arrival time and the arrival time of the direct wave and the arrival time of the first reflected wave; Based on the arrival time and the arrival time of the second reflected wave, the propagation path difference between the direct wave and the second reflected wave is calculated. A path difference calculation unit to be output, a propagation path difference between the direct wave and the first reflected wave, and a hyperbola that passes through the wave source based on the coordinates of the receiver, the receiver and the receiver Obtain a first hyperbolic equation with a focus on the mirror image of the receiver with respect to the first interface, and based on the propagation path difference between the direct wave and the second reflected wave, and the coordinates of the receiver, A hyperbola that passes through the wave source and that obtains a second hyperbola formula that focuses on the receiver and a mirror image of the receiver with respect to the second boundary surface; and a formula for the first hyperbola And an equation of the second hyperbola, and an intersection coordinate calculation unit that obtains the coordinates of the intersection of the first hyperbola and the second hyperbola, which are the coordinates of the wave source.

  Moreover, in the position estimation apparatus according to the third and fourth aspects of the present invention, the wave source includes the pulse wave from between the sea surface as the first boundary surface and the sea surface as the second boundary surface. A pressure sensor provided in the receiver and capable of measuring the water pressure at the position of the receiver, and based on the water pressure measured by the pressure sensor, A receiver coordinate calculation unit for obtaining coordinates, wherein the hyperbola acquisition unit uses the coordinates of the receiver calculated by the receiver coordinate calculation unit, and uses the first hyperbola and the second hyperbola. Is obtained.

  According to the present invention, since the coordinates of the wave source are obtained, the position of the wave source can be estimated. And the coordinate of a wave source is calculated | required based on the propagation path difference of the direct wave and reflected wave which are received by one receiver. For this reason, it is not necessary to provide a receiver at a plurality of points. Therefore, unlike the case where the receivers are provided at a plurality of points, the equipment cost is not high, and it is not necessary to install a plurality of receivers or to specify the positions of the plurality of receivers.

  Furthermore, according to the present invention, it is not necessary to perform iterative calculation for obtaining the propagation time difference between the direct wave and the reflected wave for each of a plurality of points. For this reason, the position of the wave source can be estimated in a short time.

It is a schematic diagram which shows the principle of the position estimation method of 1st Embodiment. It is a block diagram which shows the structure of the position estimation apparatus of 1st Embodiment. It is a flowchart which shows the procedure of the position estimation method of 1st Embodiment. It is a schematic diagram which shows the principle of the position estimation method of 2nd Embodiment. It is a block diagram which shows the structure of the position estimation apparatus of 2nd Embodiment. It is a flowchart which shows the procedure of the position estimation method of 2nd Embodiment. It is a schematic diagram which shows the principle of the conventional method which calculates | requires the distance of a target wave source from propagation time difference. It is a graph which shows the propagation time difference calculated | required by the conventional method.

<First Embodiment>
The first embodiment of the present invention will be described in detail. FIG. 1 is a schematic diagram illustrating the principle of the position estimation method according to the first embodiment.

  In the first embodiment, the position of a wave source H that emits a sound wave that is a pulse wave from between the sea surface W1 (first boundary surface) and the sea bottom surface W2 (second boundary surface) is used as a receiver J. To estimate. The sea water surface W1 and the sea bottom surface W2 are flat surfaces having no irregularities and are parallel to each other. A space between the sea surface W1 and the sea bottom surface W2 is filled with a uniform medium that transmits sound waves.

  In FIG. 1, the height direction (depth direction) is represented by the Z axis, and the horizontal direction is represented by the r axis. Hereinafter, as shown in FIG. 1, a case where the coordinates (0, zs) of the wave source H is obtained when the receiver J is at the coordinates (r, zr) will be described as an example.

  When sound waves are radiated from the wave source H, first, the direct wave D traveling on the straight line connecting the wave receiver J and the wave source H reaches the receiver J, and then the sea surface W1 or the sea bottom. The reflected waves R1 and R2 reflected once by W2 reach the receiver J, and then the multiple reflected waves at the sea surface W1 and the sea bottom W2 reach the receiver J.

  The propagation path length of the first reflected wave R1 that is reflected once at the seawater surface W1 and reaches the receiver J is the mirror image H1 of the wave source H with respect to the seawater surface W1 (hereinafter referred to as a lie wave source H1) directly to the receiver J. It is equal to the propagation path length of the arriving sound wave. And the locus | trajectory from which the propagation path difference of the direct wave D and 1st reflected wave R1 becomes fixed becomes the 1st hyperbola S1 which passes the receiver J focusing on the wave source H and the lie wave source H1.

  Of the sound waves radiated from the wave source H, the propagation path length of the second reflected wave R2 that is reflected once by the sea bottom surface W2 and reaches the receiver J is a mirror image H2 of the wave source H with respect to the sea bottom surface W2 (hereinafter referred to as the following image). , Equal to the propagation path length of the sound wave that reaches the receiver J directly from the lie wave source H2). The locus where the propagation path difference between the direct wave D and the second reflected wave R2 is constant becomes the second hyperbola S2 passing through the receiver J with the wave source H and the lie wave source H2 as the focal points.

  The first hyperbola S1 and the second hyperbola S2 described above can be expressed by the following Equation 1.

  The coefficient a in Equation 1 is represented by the propagation path difference between the direct wave D and the reflected wave R (in Equation 1 of the first hyperbola S1, the coefficient a is the propagation path between the direct wave D and the first reflected wave R1. (In equation 1 of the second hyperbola S2, the coefficient a is represented by the propagation path difference between the direct wave D and the second reflected wave R2). The coefficient b in Expression 1 is obtained from the coefficient a and the Z coordinate zs of the wave source H.

  When the Z coordinate zr of the receiver J or the propagation path difference between the direct wave D and the first reflected wave R1 is obtained, the coefficients a and Z (= zr) are real numbers, and the coefficients b and r are Equation 1 of the first hyperbola S1 as an unknown can be obtained.

  When the Z coordinate zr of the receiver J or the propagation path difference between the direct wave D and the second reflected wave R2 is obtained, the coefficients a and Z (= zr) are real numbers, and the coefficients b and r are Equation 1 of the second hyperbola S2 can be obtained as an unknown number.

  Then, when Equation 1 of the first and second hyperbola S1 and S2 is obtained as described above, two unknowns b and r are obtained by simultaneously using Equation 1 of these two hyperbolas S1 and S2. Can do. As a result, the required r corresponds to the horizontal distance between the receiver J and the wave source H. Further, from the coefficients a and b, the Z coordinate zs of the wave source H which is a common focal point of the first and second hyperbolas S1 and S2 can be obtained.

  Based on the above, in the first embodiment, the time T1 when the direct wave D reaches the receiver J, the time T2 when the first reflected wave R1 reaches the receiver J, and the second reflected wave R2 are received. The time T3 at which the device J is reached is specified.

  Then, based on the arrival time T1 of the direct wave D and the arrival time T2 of the first reflected wave R1, the propagation path difference K1 between the direct wave D and the first reflected wave R1 is calculated. Further, based on the arrival time T1 of the direct wave D and the arrival time T3 of the second reflected wave R2, the propagation path difference K2 between the direct wave D and the second reflected wave R2 is calculated.

  Further, the Z coordinate zr of the receiver J is obtained based on the water pressure at the position of the receiver J.

  Based on the propagation path difference K1 between the direct wave D and the first reflected wave R1 and the Z coordinate zr of the receiver J, Equation 1 of the first hyperbola S1 is obtained. Further, based on the propagation path difference K2 between the direct wave D and the second reflected wave R2 and the Z coordinate zr of the receiver J, Equation 1 of the second hyperbola S2 is obtained.

  Then, Equation 1 of the first hyperbola S1 and Equation 1 of the second hyperbola S2 are combined, and the horizontal distance r between the receiver J and the wave source H and the common of the first and second hyperbola S1 and S2. The Z coordinate zs of the focal point is obtained.

  FIG. 2 shows a hardware configuration of the position estimation apparatus A that executes the above processing.

  The position estimation device A includes the above-described receiver J and an arithmetic processing device E.

  The receiver J is provided with a sound pressure sensor 10 and a pressure sensor 11. The sound pressure sensor 10 includes a piezoelectrician, and a plurality of the sound pressure sensors 10 are arranged. The sound pressure sensor 10 may be an optical fiber type. The pressure sensor 11 measures the water pressure at the position of the receiver J.

  The arithmetic processing unit E is provided in the vicinity of the receiver J or integrally with the receiver J. The arithmetic processing device E is connected to the receiver J via a communication line, and includes an arrival time specifying unit 20, a path difference calculating unit 21, a hyperbola acquiring unit 22, a focal coordinate calculating unit 23, And a receiver coordinate calculation unit 24. Each of the above parts is realized by a circuit, for example. Or each said part is implement | achieved when CPU (Central Processing Unit) performs the process according to the program memorize | stored in the external memory | storage part.

  In addition, an input device for inputting a speed at which sound is transmitted through a medium between the sea surface W1 and the sea bottom W2 (hereinafter referred to as sound speed) and a water pressure measured by the pressure sensor 11 to the arithmetic processing unit E ( (Not shown) is provided. The arithmetic processing unit E can execute signal processing called beam forming for determining the arrival direction of the sound wave.

  Next, with reference to FIG. 3, the process performed by said position estimation apparatus A is demonstrated.

  The sound pressure sensor 10 of the receiver J sequentially receives sound waves emitted from the wave source H and reaching the receiver J (step S101). Each time the sound pressure sensor 10 receives a sound wave, the sound pressure sensor 10 performs AD conversion on the sound wave and transmits it to the arrival time specifying unit 20 of the arithmetic processing device E (step S102).

  Each time the arrival time specifying unit 20 receives a sound wave signal from the sound pressure sensor 10, it determines a time T (hereinafter, arrival time T) at which the sound wave reaches the receiver J (step S103). As the time detection method, there are various methods such as detection from a signal rising point or maximum amplitude point.

  Next, the arrival time specifying unit 20 selects three sound wave signals having large amplitudes. Then, the arrival time specifying unit 20 specifies the earliest arrival time T of the three sound waves as the arrival time T1 of the direct wave D among the arrival times T of the three sound waves. In addition, the arrival time specifying unit 20 applies a sound wave to a sound wave that arrives after the direct wave D (second and third sound waves) by signal processing called beam forming in the arithmetic processing unit E. The direction of arrival above and below is determined. Then, the arrival time specifying unit 20 sets the arrival time T2 and T3 of the reflected waves R1 and R2 as the first reflected wave R1 as the sound wave reaching from the upper direction and the second reflected wave R2 as the sound wave arrived from the lower direction. Specify (step S104).

  Next, the path difference calculation unit 21 calculates the time difference between the arrival time T1 of the direct wave D and the arrival time T2 of the first reflected wave R1 as the propagation time difference S1 between the direct wave D and the first reflected wave R1. (Step S105).

  Further, the path difference calculation unit 21 calculates the time difference between the arrival time T1 of the direct wave D and the arrival time T3 of the second reflected wave R2 as the propagation time difference S2 between the direct wave D and the second reflected wave R2. (Step S105).

  Next, the path difference calculation unit 21 calculates the propagation path difference K1 between the direct wave D and the first reflected wave R1 by multiplying the propagation time difference S1 calculated in step S105 by the speed of sound input to the input device. (Step S106).

  Further, the path difference calculation unit 21 calculates the propagation path difference K2 between the direct wave D and the second reflected wave R2 by multiplying the propagation time difference S2 calculated in step S105 by the speed of sound input to the input device. (Step S106).

  Next, the receiver coordinate calculation unit 24 calculates the Z coordinate zr (depth) of the receiver J based on the water pressure measured by the pressure sensor 11 (step S107).

  Next, the hyperbola acquisition unit 22 performs the first step based on the propagation path difference K1 between the direct wave D and the first reflected wave R1 calculated in step S106 and the Z coordinate zr of the receiver J calculated in step S107. Formula 1 of one hyperbola S1 is obtained (step S108).

  Further, the hyperbola acquisition unit 22 performs the first step based on the propagation path difference K2 between the direct wave D and the second reflected wave R2 calculated in step S106 and the Z coordinate zr of the receiver J calculated in step S107. Formula 1 of the two hyperbola S2 is obtained (step S108).

  Equation 1 of the first and second hyperbola S1 and S2 obtained in the above step S108 is such that the coefficients a and Z (= zr) are real numbers and the coefficients b and r are unknown numbers.

  Next, the focal coordinate calculation unit 23 obtains the unknowns b and r by simultaneously combining the expression 1 of the first hyperbola S1 and the expression 1 of the second hyperbola S2 (step S109). As a result, the required r corresponds to the horizontal distance between the receiver J and the wave source H. Further, the focal coordinate calculation unit 23 obtains the Z coordinate zs of the wave source H which is a common focal point of the first and second hyperbolas S1 and S2 from the coefficients a and b (step S109).

  As described above, according to the first embodiment, since the Z coordinate zs of the wave source H and the horizontal distance r between the receiver J and the wave source H are obtained, the position of the wave source H can be estimated. .

  The Z coordinate zs and the horizontal distance r of the wave source H are obtained based on the propagation path difference between the direct wave D and the reflected waves R1 and R2 received by one receiver J. For this reason, it is not necessary to provide the receiver J at a plurality of points. Therefore, unlike the case where the receivers are provided at a plurality of points, the equipment cost is not high, and it is not necessary to install a plurality of receivers or to specify the positions of the plurality of receivers.

  Further, unlike the conventional brute force method, it is not necessary to perform iterative calculation for obtaining the propagation time difference between the direct wave and the reflected wave at a plurality of points. For this reason, the position of the wave source can be estimated in a short time.

  Further, the coordinates of the receiver J are obtained based on the water pressure measured by the pressure sensor 11 of the receiver J, and the equations of the first hyperbola S1 and the second hyperbola S2 are obtained using the coordinates of the receiver J. Desired. Therefore, even when the position of the receiver J is not known or when the receiver J moves, the equations of the first hyperbola S1 and the second hyperbola S2 are obtained, and the wave source H is based on these equations. Can be obtained.

Second Embodiment

  Next, a second embodiment of the present invention will be described in detail. FIG. 4 is a schematic diagram illustrating the principle of the position estimation method according to the second embodiment.

  Similarly to the first embodiment, the second embodiment also uses the receiver J to estimate the position of the wave source H that emits a sound wave that is a pulse wave from between the sea surface W1 and the sea bottom W2. is there. In addition, as in the first embodiment, the sea water surface W1 and the sea bottom surface W2 are flat surfaces having no irregularities and are parallel to each other. A space between the sea surface W1 and the sea floor W2 is filled with a uniform medium that transmits sound waves.

  Hereinafter, as illustrated in FIG. 4, a case where the coordinates (r, zs) of the wave source H is obtained when the receiver J is at the coordinates (0, zr) will be described as an example.

  Of the sound waves generated from the wave source H, the path length of the first reflected wave R1 that is reflected once by the seawater surface W1 and reaches the receiver J is a mirror image J1 of the receiver J with respect to the seawater surface W1 (hereinafter, It is equal to the path length of the sound wave that directly reaches the lie receiver J1). The trajectory in which the propagation path difference between the direct wave D directly reaching the receiver J from the wave source H and the first reflected wave R1 is constant is focused on the receiver J and the lie receiver J1, and the wave source A first hyperbola S3 passing through H is obtained.

  Of the sound waves radiated from the wave source H, the path length of the second reflected wave R2 that is reflected once by the sea bottom W2 and reaches the receiver J is the mirror image J2 of the receiver J with respect to the sea bottom W2 ( Hereinafter, it is equal to the path length of the sound wave that directly reaches the lie receiver J2). The locus where the propagation path difference between the direct wave D directly reaching the receiver J from the wave source H and the second reflected wave R2 is constant is focused on the receiver J and the lie receiver J2, and the wave source The second hyperbola S4 passing through H is obtained.

  The first hyperbola S3 and the second hyperbola S4 described above can be expressed by the following Expression 2.

  The coefficient a in Expression 2 is represented by the propagation path difference between the direct wave D and the reflected wave R (in Expression 2 of the first hyperbola S3, the coefficient a is the propagation path between the direct wave D and the first reflected wave R1. It is represented by the difference K1.In the second hyperbola S4, the coefficient a is represented by the propagation path difference K2 between the direct wave D and the second reflected wave R2). The coefficient c in Expression 2 can be expressed by the coefficient a and the Z coordinate zr of the receiver J.

  When the Z coordinate zr of the receiver J or the propagation path difference K1 between the direct wave D and the first reflected wave R1 is obtained, the first hyperbola with coefficients a and c as real numbers and Z and r as unknown numbers. Equation 2 of S3 can be obtained.

  When the Z coordinate zr of the receiver J or the propagation path difference K2 between the direct wave D and the second reflected wave R2 is obtained, the coefficients a and c are real numbers, and Z and r are unknown numbers. Equation 2 of the two hyperbola S4 can be obtained.

  Then, when Equation 2 of the first and second hyperbola S3 and S4 is obtained as described above, two unknowns Z and r are obtained by simultaneous Equation 2 of these two hyperbola S3 and S4. Can do. As a result, the obtained Z corresponds to the Z coordinate zs of the wave source H, which is the intersection of the second hyperbola S3, S4, and the obtained r is the horizontal distance between the receiver J and the wave source H (the wave source H r coordinate).

  Based on the above, in the second embodiment, the arrival times T1, T2, and T3 of the direct wave D and the reflected waves R1 and R2 are specified as in the first embodiment. Based on these arrival times T1, T2 and T3, the propagation path difference K1 between the direct wave D and the first reflected wave R1 and the propagation path difference K2 between the direct wave D and the second reflected wave R2 are calculated. .

  Then, based on the water pressure at the position of the receiver J, the Z coordinate zr of the receiver J is obtained.

  Based on the propagation path difference K1 between the direct wave D and the first reflected wave R1 and the Z coordinate zr of the receiver J, Equation 2 of the first hyperbola S3 is obtained. Further, based on the propagation path difference K2 between the direct wave D and the second reflected wave R2 and the Z coordinate zr of the receiver J, Equation 2 of the second hyperbola S4 is obtained.

  Then, Equation 2 of the hyperbola S3 and S4 is simultaneously provided to calculate the Z coordinate zs of the wave source H that is the intersection of the second hyperbola S3 and S4 and the horizontal distance r between the receiver J and the wave source H. .

  FIG. 5 shows a hardware configuration of the position estimation apparatus B that executes the above processing.

  The position estimation device B includes a receiver J and an arithmetic processing device F.

  The receiver J is provided with a sound pressure sensor 10 and a pressure sensor 11. The sound pressure sensor 10 and the pressure sensor 11 are the same as in the first embodiment. Therefore, detailed description is omitted.

  The arithmetic processing unit F is connected to the receiver J via a communication line, and includes an arrival time specifying unit 20, a path difference calculation unit 21, a hyperbola acquisition unit 25, an intersection coordinate calculation unit 26, And a receiver coordinate calculation unit 24. Each of the above parts is configured by a circuit, for example. Or each said part is comprised because CPU performs the process according to the program memorize | stored in the external memory | storage part. Further, the arithmetic processing unit F is provided with an input device for inputting the sound velocity in the medium and the water pressure measured by the pressure sensor 11. Further, the arithmetic processing unit E can perform signal processing called beam forming.

  Next, with reference to FIG. 6, the process performed by said position estimation apparatus F is demonstrated.

  Steps S201 and S202 are executed by the receiver J, steps S203 and S204 are executed by the arrival time specifying unit 20, steps S205 and S206 are executed by the path difference calculating unit 21, and step S207 is received by the receiver. This is executed by the coordinate calculation unit 24. These steps S201 to S207 are the same as steps S101 to S107 in FIG. Therefore, below, step S208 and after are demonstrated.

  The hyperbola acquisition unit 25 generates a first hyperbola based on the propagation path difference K1 between the direct wave D and the first reflected wave R1 calculated in step S206 and the Z coordinate zr of the receiver J calculated in step S207. Formula 2 of S3 is obtained (step S208).

  Further, the hyperbola acquisition unit 25 determines the first based on the propagation path difference K2 between the direct wave D and the second reflected wave R2 calculated in step S206, and the Z coordinate zr of the receiver J calculated in step S207. Equation 2 of the two hyperbola S4 is obtained (step S208).

  Expression 2 of the first and second hyperbolas S3 and S4 obtained in the above step S208 is such that the coefficients a and c are real numbers and Z and r are unknown numbers.

  Next, the intersection coordinate calculation unit 26 obtains the unknowns Z and r by simultaneously combining the expression 2 of the first hyperbola S3 and the expression 2 of the second hyperbola S4 (step S209). By this processing, Z obtained is the Z coordinate zs of the wave source H that is the intersection of the first and second hyperbolic curves S3 and S4, and r obtained is the horizontal distance between the receiver J and the wave source H ( R coordinate of the wave source H).

  As described above, also in the second embodiment, since the Z coordinate zs and the horizontal distance r of the wave source H are obtained, the position of the wave source H can be estimated.

  Also in the second embodiment, the position of the wave source H is estimated using the propagation path difference between the direct wave D and the reflected wave received by one receiver J. For this reason, it is not necessary to provide the receiver J at a plurality of points. Therefore, the equipment cost is not expensive, and the labor for installing the plurality of receivers J at desired positions and the labor for specifying the positions of the plurality of receivers J are not required. In addition, since iterative calculation for obtaining the propagation time difference between the direct wave D and the reflected wave at a plurality of points is not required, the position of the wave source H can be estimated in a short time.

  Further, the coordinates of the receiver J are obtained based on the water pressure measured by the pressure sensor 11 of the receiver J, and the equations of the first hyperbola S3 and the second hyperbola S4 are obtained using the coordinates of the receiver J. Is required. Therefore, even when the position of the receiver J is not known or when the receiver J moves, the equations of the first hyperbola S3 and the second hyperbola S4 are obtained, and the wave source H is based on these equations. Can be obtained.

  The present invention is not limited to the first and second embodiments described above, and various modifications can be made.

  For example, in the first and second embodiments described above, an example in which the sound speed in the medium is uniform has been shown, but the sound speed in the medium may not be uniform. In this case, the average value of the sound speed is input to the arithmetic processing devices E and F (FIGS. 2 and 5). Then, in step S106 of FIG. 3 and step S206 of FIG. 6, the propagation path differences K1, K2 are calculated by multiplying the propagation speed difference S1, S2 by the average value of the sound speed.

  In the first and second embodiments, an example in which the boundary surface (sea surface W1 or sea bottom surface W2) is a plane is shown, but the present invention can also be applied to a case where the boundary surface has undulations or irregularities. is there. If the boundary surface has undulations or irregularities, the average plane is set in the direction in which the boundary surface extends (corresponding to the r-axis in FIGS. 1 and 4).

  In the first and second embodiments, the example of obtaining the coordinates of the receiver J based on the measurement value of the pressure sensor has been shown. However, when the receiver J is fixed and stationary, The coordinates of the receiver J may be input to the arithmetic processing devices E and F, and the first hyperbola and second hyperbola equations may be obtained based on the input values.

  In the first and second embodiments, the example in which the wave source H outputs a sound wave has been described. However, the present invention can also be applied when the wave source outputs a pulse wave (such as an electromagnetic wave or an elastic wave) other than the sound wave. It is.

  For example, when the wave source outputs electromagnetic waves or elastic waves, a receiver that can receive the electromagnetic waves and elastic waves is provided between the first boundary surface and the second boundary surface. In the processing corresponding to step S101 in FIG. 3 or step S201 in FIG. 6, the receiver receives the direct wave that reaches the receiver directly from the wave source, or is reflected once by the first boundary surface. The first reflected wave that has reached the wave detector and the second reflected wave that has been reflected once at the second boundary surface and reached the wave receiver are received. In the processing corresponding to step S106 in FIG. 3 or step S206 in FIG. 6, the propagation path difference between the direct wave and the first and second reflected waves is based on the speed of light and the elastic wave input to the arithmetic processing unit. Is calculated.

DESCRIPTION OF SYMBOLS 11 Pressure sensor 20 Arrival time specific | specification part 21 Path | route difference calculation part 22, 25 Hyperbola acquisition part 23 Focus coordinate calculation part 24 Receiver coordinate calculation part 26 Intersection coordinate calculation part A Position estimation apparatus D Direct wave J Receiver H Wave source H1 Mirror image of wave source H with respect to first boundary surface H2 Mirror image of wave source H with respect to second boundary surface S1 First hyperbola S2 Second hyperbola R1 First reflected wave R2 Second reflected wave W1 Seawater surface (first boundary surface)
W2 Sea floor (second boundary surface)

Claims (6)

A method for estimating a position of a wave source that emits a pulse wave from between a sea surface and a sea surface ,
In the installed receivers between the sea surface and the sea floor, a reception step of receiving a pulse emitted from the wave source,
The arrival time of the direct wave that has directly reached the receiver from the wave source, the arrival time of the first reflected wave that has reflected once on the sea surface and has reached the receiver, and is reflected once on the sea floor. An arrival time specifying step for specifying the arrival time of the second reflected wave that has reached the receiver;
Based on the arrival time of the direct wave and the arrival time of the first reflected wave, a propagation path difference between the direct wave and the first reflected wave is calculated, and the arrival time of the direct wave and the second reflected wave A path difference calculating step for calculating a propagation path difference between the direct wave and the second reflected wave based on the arrival time;
Based on the propagation path difference between the direct wave and the first reflected wave, and the coordinates of the receiver, it is a hyperbola that passes through the receiver, and is a mirror image of the wave source with respect to the wave source and the sea surface . A hyperbola that passes through the receiver based on the propagation path difference between the direct wave and the second reflected wave and the coordinates of the receiver; A hyperbola acquisition step for obtaining a second hyperbola formula focusing on the wave source and a mirror image of the wave source with respect to the seabed ;
A focal coordinate calculation step for obtaining a common focal point coordinate of the first hyperbola and the second hyperbola as coordinates of the wave source by combining the first hyperbola equation and the second hyperbola equation; Wave source position estimation method. A method for estimating a position of a wave source that emits a pulse wave from between a sea surface and a sea surface ,
In the installed receivers between the sea surface and the sea floor, a reception step of receiving a pulse emitted from the wave source,
The arrival time of the direct wave that has directly reached the receiver from the wave source, the arrival time of the first reflected wave that has reflected once on the sea surface and has reached the receiver, and is reflected once on the sea floor. An arrival time specifying step for specifying the arrival time of the second reflected wave that has reached the receiver;
Based on the arrival time of the direct wave and the arrival time of the first reflected wave, a propagation path difference between the direct wave and the first reflected wave is calculated, and the arrival time of the direct wave and the second reflected wave A path difference calculating step for calculating a propagation path difference between the direct wave and the second reflected wave based on the arrival time;
Based on the propagation path difference between the direct wave and the first reflected wave, and the coordinates of the receiver, the hyperbola passes through the wave source, and the receiver and the seawater surface A hyperbola that passes through the wave source based on the propagation path difference between the direct wave and the second reflected wave and the coordinates of the receiver; A hyperbola obtaining step for obtaining a second hyperbola formula focusing on the receiver and a mirror image of the receiver with respect to the seabed ;
A position of a wave source comprising: an intersection point coordinate calculating step for obtaining coordinates of an intersection of the first hyperbola and the second hyperbola as coordinates of the wave source by simultaneously combining the expression of the first hyperbola and the expression of the second hyperbola Estimation method. The wave source from between the front Kiumi water before Kiumi bottom, which emits a sound wave which is the pulse wave, wherein the wave receiver, capable of measuring pressure at the location of the receivers A pressure sensor is provided,
A receiver coordinate calculation step for obtaining coordinates of the receiver based on the water pressure measured by the pressure sensor;
3. The wave source according to claim 1, wherein, in the hyperbola acquisition step, equations of the first hyperbola and the second hyperbola are obtained using the coordinates of the receiver calculated in the receiver coordinate calculation step. Location estimation method. A device for estimating the position of a wave source that emits a pulse wave from between the sea surface and the sea surface ,
A receiver installed between the sea water surface and the sea bottom surface for receiving a pulse wave radiated from the wave source;
The arrival time of the direct wave that has directly reached the receiver from the wave source, the arrival time of the first reflected wave that has reflected once on the sea surface and has reached the receiver, and is reflected once on the sea floor. An arrival time specifying unit for specifying the arrival time of the second reflected wave that has reached the receiver;
Based on the arrival time of the direct wave and the arrival time of the first reflected wave, a propagation path difference between the direct wave and the first reflected wave is calculated, and the arrival time of the direct wave and the second reflected wave A path difference calculating unit that calculates a propagation path difference between the direct wave and the second reflected wave based on the arrival time;
Based on the propagation path difference between the direct wave and the first reflected wave, and the coordinates of the receiver, it is a hyperbola that passes through the receiver, and is a mirror image of the wave source with respect to the wave source and the sea surface . A hyperbola that passes through the receiver based on the propagation path difference between the direct wave and the second reflected wave and the coordinates of the receiver; A hyperbola acquisition unit for obtaining a formula of a second hyperbola focusing on the wave source and a mirror image of the wave source with respect to the seabed ;
A focal coordinate calculation unit that obtains a common focal point coordinate of the first hyperbola and the second hyperbola as coordinates of the wave source by combining the first hyperbola equation and the second hyperbola equation; Position estimation device. A device for estimating the position of a wave source that emits a pulse wave from between the sea surface and the sea surface ,
A receiver installed between the sea water surface and the sea bottom surface for receiving a pulse wave radiated from the wave source;
The arrival time of the direct wave that has directly reached the receiver from the wave source, the arrival time of the first reflected wave that has reflected once on the sea surface and has reached the receiver, and is reflected once on the sea floor. An arrival time specifying unit for specifying the arrival time of the second reflected wave that has reached the receiver;
Based on the arrival time of the direct wave and the arrival time of the first reflected wave, a propagation path difference between the direct wave and the first reflected wave is calculated, and the arrival time of the direct wave and the second reflected wave A path difference calculating unit that calculates a propagation path difference between the direct wave and the second reflected wave based on the arrival time;
Based on the propagation path difference between the direct wave and the first reflected wave, and the coordinates of the receiver, the hyperbola passes through the wave source, and the receiver and the seawater surface A hyperbola that passes through the wave source based on the propagation path difference between the direct wave and the second reflected wave and the coordinates of the receiver; A hyperbola acquisition unit for obtaining an expression of a second hyperbola focusing on the receiver and a mirror image of the receiver with respect to the seabed ;
A position estimation apparatus comprising: an intersection point coordinate calculation unit that obtains the coordinates of the intersection point of the first hyperbola and the second hyperbola, which are the coordinates of the wave source, by combining the first hyperbola equation and the second hyperbola equation . The wave source from between the front Kiumi water before Kiumi bottom, which emits a sound wave which is the pulse wave,
A pressure sensor provided in the receiver and capable of measuring the water pressure at the position of the receiver;
A receiver coordinate calculation unit for obtaining coordinates of the receiver based on the water pressure measured by the pressure sensor;
6. The position estimation device according to claim 4, wherein the hyperbola acquisition unit obtains expressions of the first hyperbola and the second hyperbola using the coordinates of the receiver calculated by the receiver coordinate calculation unit. .