JP2023028225A - Propagation delay time calculation device, propagation delay time calculation system, method for propagation delay time calculation and program - Google Patents

Abstract

To obtain a propagation delay time calculation device that calculates a propagation delay time with high accuracy while suppressing a calculation cost.SOLUTION: A propagation delay time calculation device that calculates a propagation delay time until the arrival of sound wave transmitted from a sound transmitter at any time at a sound receiver when either one or both of the sound transmitter and the sound receiver travel has: first propagation calculation means for obtaining a provisional propagation delay time using a predetermined computational model for a sound transmitter position and a sound receiver position at the time; average velocity calculation means for obtaining a sound receiver average velocity at the provisional propagation delay time; propagation delay time estimation means for calculating an estimated propagation delay time from the sound receiver average velocity and the sound transmitter position and the sound receiver position at the time; and second propagation calculation means for calculating a propagation delay time from the sound transmitter position at the time to the sound receiver position expected by the propagation delay time using the computational model.SELECTED DRAWING: Figure 6

Description

The present invention provides a propagation delay time calculation device, a propagation delay time calculation system, and a propagation delay time calculating propagation delay time when one or both of a wave transmitter and a wave receiver move in a simulator that simulates wave propagation. The present invention relates to a calculation method and a program for causing a computer to execute the method.

2. Description of the Related Art Conventionally, there is known a device for generating a signal simulating a frequency shift caused by wave propagation delay and Doppler effect in a simulator that simulates wave propagation from a sound source to a wave receiving point. Further, when the waves to be analyzed are radio waves, there is known a radar device that emits radio waves to the surface of the sea, measures the reflected waves, and observes oceanographic information such as the flow of ocean currents (for example, Patent Document 1 reference).

In the radar device disclosed in Patent Document 1, the simulator may be used for performance evaluation during the product development process. In the above simulator, when simulating and generating a received wave signal reflecting both the delay time due to sound wave propagation and the frequency shift due to the Doppler effect, the propagation delay time of the transmitted wave at a certain time is calculated.

JP-A-11-83992

However, in order to calculate the propagation delay time with high accuracy, it is necessary to calculate the propagation between the position of the wave receiver at the true wave reception time considering the propagation delay time, and the calculation cost increases. be.

The propagation delay time calculation device according to the present invention is a device for calculating a propagation delay time until a wave transmitted from the transmitter and the receiver arrives at the receiver at an arbitrary time when one or both of the transmitter and the receiver are moved. is a propagation delay time calculation device for calculating a propagation delay time of a provisional propagation delay time, which is a provisional propagation delay time, using a calculation model predetermined for the position of the transmitter and the position of the receiver at the time average speed calculation means for obtaining a receiver average speed that is the average speed of the receiver at the provisional propagation delay time; and the average speed of the receiver and the transmitted wave at the time propagation delay time estimating means for calculating an estimated propagation delay time from the transmitter position and the receiver position; and a propagation delay from the transmitter position at the time to the receiver position predicted by the estimated propagation delay time. and second propagation calculation means for calculating the time using the calculation model.

In the propagation delay time calculation system according to the present invention, when one or both of a transmitter and a receiver move, a wave transmitted from the transmitter at an arbitrary time arrives at the receiver. A propagation delay time calculation system for calculating the propagation delay time of the provisional propagation delay time using a calculation model predetermined for the position of the transmitter and the position of the receiver at the time average speed calculation means for obtaining a receiver average speed that is the average speed of the receiver at the provisional propagation delay time; and the average speed of the receiver and the transmitted wave at the time propagation delay time estimating means for calculating an estimated propagation delay time from the transmitter position and the receiver position; and a propagation delay from the transmitter position at the time to the receiver position predicted by the estimated propagation delay time. and second propagation calculation means for calculating the time using the calculation model.

According to the propagation delay time calculation method according to the present invention, when one or both of a transmitter and a receiver move, a wave transmitted from the transmitter at an arbitrary time arrives at the receiver. A propagation delay time calculation method for calculating the propagation delay time of, wherein the provisional propagation delay time is a provisional propagation delay time using a calculation model predetermined for the position of the transmitter and the position of the receiver at the time obtaining a receiver average velocity that is the average velocity of the receiver at the provisional propagation delay time; determining the receiver average velocity, the transmitter position and the receiver position at the time; and calculating, using the calculation model, the propagation delay time from the position of the transmitter at the time to the position of the receiver predicted by the estimated propagation delay time. and

A program according to the present invention is a propagation delay time until a wave transmitted from the transmitter and the receiver arrives at the receiver at an arbitrary time when one or both of the transmitter and the receiver move. a first propagation calculation means for calculating a provisional propagation delay time, which is a provisional propagation delay time, using a calculation model predetermined for the position of the transmitter and the position of the receiver at the time; average velocity calculation means for obtaining an average velocity of the receiver which is the average velocity of the receiver during the provisional propagation delay time; and from the average velocity of the receiver and the transmitter position and the receiver position at the time. Propagation delay time estimating means for calculating an estimated propagation delay time; and calculating a propagation delay time from the position of the transmitter at the time to the position of the receiver predicted by the estimated propagation delay time using the calculation model. and a second propagation calculation means for performing.

In the present invention, even if one or both of the transmitter and the receiver perform arbitrary motion accompanied by acceleration, the motion between the transmitter and the receiver is delayed for a period of time corresponding to the tentative propagation delay time. It is replaced by uniform linear motion by the average velocity of the receiver in the section. Therefore, it is possible to estimate a wave reception time that approximates the true wave reception time by one propagation calculation without considering the combination of the transmitter position at the wave transmission time and the receiver positions at a plurality of wave reception times. can be done. As a result, it is possible to accurately calculate the propagation delay time while suppressing the calculation cost.

FIG. 4 is a schematic diagram showing an example of temporal changes in position vectors of a transmitter that transmits a simulated sound wave and a receiver that receives the sound wave. 9 is a flow chart showing a procedure of a propagation delay time calculation method according to Comparative Example 1; FIG. 11 is a table showing an example of search for received wave time lag; FIG. FIG. 11 is an image diagram for explaining a propagation delay time calculation method of Comparative Example 2; 1 is a diagram showing a configuration example of a propagation delay time calculation device according to Embodiment 1; FIG. 6 is a functional block diagram showing a configuration example of a control unit shown in FIG. 5; FIG. 7 is a diagram showing an example of information stored in a transmitter position memory shown in FIG. 6; FIG. 7 is a diagram showing an example of information stored in a receiver position memory shown in FIG. 6; FIG. 7 is a diagram showing an example of information stored in a receiver speed memory shown in FIG. 6; FIG. 7 is a diagram showing an example of information stored in a propagation information memory shown in FIG. 6; FIG. FIG. 4 is an image diagram for explaining a propagation delay time calculation method according to Embodiment 1; 4 is a flow chart showing a procedure of a propagation delay time calculation method according to Embodiment 1; FIG. 4 is a diagram showing an example of one-dimensional acceleration motion opposition; 14 is a table showing various values at each time in the example shown in FIG. 13 in Embodiment 1. FIG. FIG. 9 is a functional block diagram showing one configuration example of a control unit of the propagation delay time calculation device according to Embodiment 2; 9 is a flow chart showing the procedure of a propagation delay time calculation method according to Embodiment 2; 14 is a table showing various values at each time in the example shown in FIG. 13 in Embodiment 2. FIG. 4 is a block diagram showing another configuration example of the propagation delay time calculation device according to Embodiment 1; FIG.

Embodiment 1.
The propagation delay time calculation apparatus according to the first embodiment is a simulator that simulates wave propagation, and when one or both of the wave transmitter and wave receiver move, the propagation delay time, which is the delay time due to wave propagation, is It is a computing device. Specifically, the propagation delay time calculation device performs a pseudo signal generation process that simulates a received wave signal that propagates through a medium with sound radiated from a transmitter and arrives at a receiver. A propagation delay time required for a sound wave transmitted from a wave device to reach a wave receiver is obtained. As a result, it is possible to generate a simulated received wave signal that reflects both the delay time due to propagation and the frequency shift due to the Doppler effect.

Before explaining the configuration of the propagation delay time calculation device according to the first embodiment, propagation of sound will be explained as an example of waves to be simulated by the propagation delay time calculation device. In the formulas and tables, Greek letters or Roman letters representing various parameters are written in bold (vector notation), but the vector notation is omitted in the text.

FIG. 1 is a schematic diagram showing an example of temporal changes in position vectors of a transmitter that transmits a simulated sound wave and a receiver that receives the sound wave. As shown in FIG. 1, consider the situation in which the position vector p _s of the transmitter and the position vector p _r of the receiver are time-varying when the transmitter and receiver move.

It is assumed that the position vector p _s (t) and velocity vector v _s (t) of the transmitter at each time and the speed of sound c(p) at each position are given in advance. For the receiver at each time, the position vector p _r (t) and velocity vector v _r (t), and the speed of sound c(p) at each position are given in advance. p means an arbitrary position vector. The subscript s of each vector means a source, and the subscript r means a receiver.

Next, in order to facilitate understanding of the propagation delay time calculation method by the propagation delay time calculation device of the first embodiment, two comparative examples will be described.

Using Fig. 1 as a model, when generating a pseudo signal that simulates a received wave signal that propagates through a medium with sound radiated from a transmitter and arrives at a receiver, By obtaining the propagation delay time required for the waved sound wave to reach the receiver, it is possible to simulate the received wave signal reflecting both the delay time due to propagation and the frequency shift due to the Doppler effect.

(Comparative example 1)
A propagation delay time calculation method of Comparative Example 1 will be described. If the transmitter and receiver are stationary, the propagation path should be considered from the stationary transmitter position to the receiver position. However, when one or both of the transmitter and receiver are moving, as shown in FIG. 1, the position of the receiver moves by the propagation delay time.

Therefore, in Comparative Example 1, the propagation delay time to the moved receiver position is obtained. FIG. 2 is a flow chart showing the procedure of the propagation delay time calculation method according to Comparative Example 1. As shown in FIG. i is the transmission time index. The transmission time index i corresponds to an index indicating the time at which sound waves are simulated to be transmitted from the transmitter at a constant cycle. The initial value of the transmission time index i is 0, and the final transmission time index, which is the final index of the transmission time index i, is L.

Regarding the propagation delay time estimation processing in step S502, the case of transmission time index i=0 (step S501) will be described. FIG. 3 is a table showing an example of searching for the received wave time lag. In order _to estimate _{the propagation} delay time more accurately _, as shown in FIG _. It is necessary to calculate the propagation delay times d _{t0 and tn} by performing propagation calculations with the receiver position p _r (t _n ). The propagation delay times _{dt0 and tn} can be obtained, for example, by acoustic ray calculation such as the Bellhop model.

Here, the Bellhop model is a computational model for predicting the sound pressure field in ocean acoustics. , propagation loss, angle of arrival, etc.

Using the propagation delay times _{dt0 and tn} , the received wave time difference τ̂(0) is calculated as in the following equation (1). In the equations and tables, the received wave time lag is represented by a symbol with a ^ on top of τ.

Equation (1) is a propagation delay time at which the time difference between the time of transmission and the time of reception that can be assumed matches the propagation delay time to the position of the receiver at the time of reception that can be assumed is the estimated propagation delay time , indicates that it is selected. Taking FIG. 3 as an example, the delay time surrounded by the thick line frame is selected as the estimated propagation delay time.

However, in the method of Comparative Example 1, in order to solve the equation (1), it is necessary to calculate the propagation delay times d _t0,tn (n=0, 1, . computational cost increases.

(Comparative example 2)
Next, the method of Comparative Example 2 will be described with reference to FIGS. 2 and 4. FIG. Comparative Example 2 is a method that replaces the calculation of Equation (1), considering that two assumptions are satisfied. FIG. 4 is an image diagram for explaining the propagation delay time calculation method of Comparative Example 2. In FIG.

As assumption 1, regarding the movement of the receiver, it is assumed that the movement of the receiver is uniform linear motion with a speed of _vr between time t ₀ and time (t ₀ +τ^(0)) as shown in FIG. do. As _assumption 2 _, the propagation _{of sound} may be any propagation including refraction. We assume linear propagation of the isosonic field. The distance l t0,tn between the transmitter position p _s (t ₀ ) at the transmission time t ₀ and the receiver position p _r ( _{t n )} at the transmission time _{t n} is given by equation (2): be done.

From assumption 1 of uniform linear motion, equation (2) can be rewritten as equation (3).

_{Subsequently , the following} equation ( ₄ ) _is solved to obtain The time required for propagation of the distance l _t0,tn is found to be (t _n -t ₀ ).

Here, on the right side of equation (4), the effect of the receiver velocity v _r on the sound propagation path length is the sound propagation direction {p _r (t ₀ ) −p _s (t ₀ )}. Therefore, the right side of Equation (4) can be rewritten as Equation (5) below.

By rearranging the equations (4) and (5), the equation (6) is obtained.

In this way, assuming straight propagation of a uniform linear motion and a uniform sound velocity field, the estimated propagation delay time τ^(0) is the moving direction v _r of the wave receiver and the traveling direction of the wave {p _r (t ₀ ) -p _s (t ₀ )}, it can be obtained by formulating considering the change in the propagation path at time t ₀ . Thus, in Comparative Example 2, referring to the procedure shown in FIG. 2, when the transmission time index i=0 (step S501), the estimated propagation delay time τ^(0) is calculated in step S502. .

In the propagation calculation process in step S503, the propagation delay time τ(0) between the transmitter position p _s (t ₀ ) and the receiver position p _r (t ₀ +τ^(0)) is determined by the Bellhop model or the like. Calculated by sound ray calculation. Thereafter, while updating the wave transmission time index i (step S505), the processing of steps S502 to S503 is repeated until the wave transmission time index i reaches the final wave transmission time index L.

As described above, in the simulation of the received wave signal that reflects both the delay time due to propagation and the frequency shift due to the Doppler effect, in order to accurately calculate the propagation delay time of a wave transmitted at a certain time, the propagation delay time should be calculated with respect to the position of the receiver at the true time of reception.

In the method of Comparative Example 1, it is necessary to perform propagation calculations for the number of combinations between the transmitter position and the receiver position at each transmission time to calculate the propagation delay time, and the calculation cost is high. There is a problem that the

On the other hand, the method of Comparative Example 2 assumes that the movement of the receiver is uniform linear motion, and that the propagation of sound waves in the movement of the receiver within the propagation delay time is uniform sound velocity (straight propagation). The estimated propagation delay time can be calculated without solving the combinatorial problem. However, when the receiver makes an arbitrary motion accompanied by acceleration, in equation (6), if _vr is the instantaneous receiver velocity, the longer the distance between the transmitter and the receiver, the more the motion There is a problem that the estimation error increases as the acceleration of the motor increases.

On the other hand, in the propagation delay time calculation method of the first embodiment, in the method of estimating the propagation delay time for any motion accompanied by acceleration, the adaptive block length according to the position and motion is averaged An estimated propagation delay time is obtained using the receiver velocity vector. According to the first embodiment, it is possible to obtain an estimated propagation delay time with an improved estimation error without requiring propagation calculation between the transmitter position and the receiver position in many combinations of time lags. , which can reduce the computational cost.

The configuration of the propagation delay time calculation device according to the first embodiment will be described. 5 is a diagram showing a configuration example of a propagation delay time calculation device according to Embodiment 1. FIG.

The propagation delay time calculation device 1 is an information processing device such as a computer. As shown in FIG. 5 , the propagation delay time calculation device 1 has an input section 2 , a storage section 3 , a control section 4 and an output section 5 . The storage unit 3 is, for example, an HDD (Hard Disk Drive) device. The output unit 5 is, for example, a display device. The control unit 4 has a memory 11 that stores programs and a CPU (Central Processing Unit) 12 that executes processes according to the programs. The memory 11 is, for example, a non-volatile memory such as flash memory.

FIG. 6 is a functional block diagram showing one configuration example of the control unit shown in FIG. The control unit 4 has a first propagation calculation means 21 , an average speed calculation means 22 , a propagation delay time estimation means 23 and a second propagation calculation means 24 . A first propagation calculation means 21, an average speed calculation means 22, a propagation delay time estimation means 23 and a second propagation calculation means 24 are configured by the CPU 12 executing the programs.

The storage unit 3 is divided into a plurality of memory areas. In the configuration example shown in FIG. 6, the storage unit 3 includes a transmitter position memory 31, a receiver position memory 32, a receiver velocity memory 33, and a propagation information memory 34 as memory areas for storing data. have Hereinafter, the transmitter position memory 31 and the receiver position memory 32 are collectively referred to as "position memory", and the receiver speed memory 33 is abbreviated as "speed memory".

The configuration of each memory will be explained. 7 is a diagram showing an example of information stored in the transmitter position memory shown in FIG. 6. FIG. The transmitter position memory 31 stores the transmitter position information shown in FIG. The transmitter position information is information in which the transmitter position _ps is stored corresponding to the transmission time index i. 8 is a diagram showing an example of information stored in a receiver position memory shown in FIG. 6. FIG. The receiver position memory 32 stores the receiver position information shown in FIG. The receiver position information is information in which the receiver position _pr is stored corresponding to the transmission time index i.

9 is a diagram showing an example of information stored in the receiver speed memory shown in FIG. 6. FIG. The receiver speed memory 33 stores receiver speed information shown in FIG. The receiver velocity information is information in which the receiver velocity _vr is stored corresponding to the transmission time index i. 10 is a diagram showing an example of information stored in the propagation information memory shown in FIG. 6. FIG. The propagation information memory 34 stores the propagation information shown in FIG. The propagation information is information in which the propagation delay time τ and the propagation loss TL (transmission on loss) are stored corresponding to the transmission time index i. The propagation loss TL means an amplitude attenuation amount [dB] indicating how much the amplitude is attenuated from the time of sound wave transmission, with reference to the time of sound wave transmission from the sound source.

Next, the configuration of the control section 4 will be described. The first propagation calculation means 21 receives the transmission time index i, the information in the transmitter position memory 31, and the information in the receiver position memory 32, and calculates the position of the transmitter and the receiver at the time of transmission. A provisional propagation delay time, which is a provisional propagation delay time, is calculated. The first propagation calculation means 21 outputs the calculated provisional propagation delay time to the average velocity calculation means 22 .

The average velocity calculation means 22 receives the tentative propagation delay time output from the first propagation calculation means 21 and the information in the receiver velocity memory 33, and calculates the average velocity of the receiver, which is the average velocity of the receiver. Calculate The average velocity calculator 22 uses the provisional propagation delay time as the time interval for calculating the receiver average velocity. The average velocity calculator 22 outputs the calculated receiver average velocity to the propagation delay time estimator 23 .

The propagation delay time estimating means 23 inputs the receiver average velocity output from the average velocity calculating means 22, the information in the transmitter position memory 31, and the information in the receiver position memory 32, and estimates the propagation delay. Calculate time. The propagation delay time estimation means 23 outputs the estimated propagation delay time to the second propagation calculation means 24 .

The second propagation calculating means 24 receives the estimated propagation delay time output from the propagation delay time estimating means 23, the information in the transmitter position memory 31, and the information in the receiver position memory 32, and receives the transmitted wave. The propagation delay time from the position of the transmitter at the time to the position of the receiver predicted by the estimated propagation delay time is calculated. As a result, a highly accurate propagation delay time is calculated. The second propagation calculation means 24 writes the calculated propagation delay time into the propagation information memory 34 .

Each means of the first propagation calculation means 21, the average speed calculation means 22, the propagation delay time estimation means 23, and the second propagation calculation means 24 updates the transmission time index i, and Repeat process.

Next, the operation of the propagation delay time calculation device 1 according to the first embodiment will be explained. FIG. 11 is an image diagram for explaining the propagation delay time calculation method according to the first embodiment. 12 is a flow chart showing the procedure of the propagation delay time calculation method according to Embodiment 1. FIG.

As in Comparative Examples 1 and 2, taking the propagation of sound waves as an example, propagation in pseudo signal generation that simulates the received waveform of the wave receiver in a situation where the position vectors of the wave transmitter and the wave receiver change over time. A method of calculating the delay time will be described. Here, the transmitter position information at each time is stored in the transmitter position memory 31, the receiver position information at each time is stored in the receiver position memory 32, and the receiver velocity at each time is stored. information is stored in the receiver speed memory 33 .

First, the control unit 4 initializes the transmission time index i to 0 (step S101). In step S102, the first propagation calculation means 21 performs the first propagation calculation processing as follows. From the information in the transmitter position memory 31, the first propagation calculation means 21 calculates the transmitter position _ps (i)=[ _ps,x (i),ps _,y (i),p _s,z (i)]. Further, the first propagation calculation means 21 calculates, from the information in the receiver position memory 32, the receiver position p _r (i)=[ _{pr, x} (i), p _{r , y} (i), p _r,z (i)]. Then, the first propagation calculation means 21 obtains a provisional propagation delay time τ'(i) between p _s (i)→p _r (i). The tentative propagation delay time τ'(i) corresponds to the tentative propagation delay time. For example, a provisional propagation delay time can be obtained using a sound ray calculation model such as the Bellhop model.

In step S103, the average velocity calculation means 22 performs receiver average velocity calculation processing as follows. The average velocity calculation means 22 refers to v _r (i), _{v r} (i+1), . Then, the average velocity calculation means 22 calculates the average velocity vector v _r [ave] of the wave receiver using Equation (7). In the equations and tables, the average velocity vector of the receiver is represented by a symbol with "-" indicating the average value above the receiver velocity vector _vr .

ceil[·] shown in Equation (7) means a rounding up operation toward positive infinity. Also, Δt is the time interval of positions stored in the position memory and the time interval of velocities stored in the velocity memory. By calculating the average velocity of the receiver using Equation (7), any motion in the time interval from the time of wave transmission to the time of wave reception is approximated to uniform linear motion of the average velocity of the receiver.

In step S104, the propagation delay time estimation means 23 performs propagation delay time estimation processing as follows. The propagation delay _time estimating means 23 calculates the estimated propagation delay time τ _^ ( Calculate i).

In step S105, the second propagation calculation means 24 performs the second propagation calculation processing as follows. The second propagation calculation means 24 calculates the distance between the transmitter position p _s (i) at the transmission time and the receiver position p _r (i+round[τ^(i)/Δt]) at the true reception time. propagation delay time τ(i) of is calculated by sound ray calculation of the Bellhop model or the like in the same manner as in step S102. Here, round [·] means a rounding operation. The second propagation calculation means 24 stores the calculated propagation delay time τ(i) at the address corresponding to the transmission time index i in the propagation information of the propagation information memory 34 .

In step S106, the control unit 4 determines whether or not the wave transmission time index i is the final wave transmission time index L. As a result of the determination, if the wave transmission time index i is not the final wave transmission time index L, the control unit 4 adds 1 to the wave transmission time index i (step S107) and returns to the process of step S102. In this way, while updating the wave transmission time index i, the processing of steps S102 to S105 is repeated until the wave transmission time index i reaches the final wave transmission time index L. FIG.

The effect of the propagation delay time calculation method by the propagation delay time calculation device 1 of the first embodiment will be described. As described with reference to FIG. 12, in the first embodiment, even if one or both of the transmitter and the receiver perform arbitrary motion accompanied by acceleration, the transmitter and the receiver are is replaced by uniform linear motion due to the mean velocity of the receiver in the time interval corresponding to the tentative propagation delay time. As a result, without considering the combination of the transmitter position of the wave transmission time and the receiver positions of a plurality of wave reception times, the wave reception time approximated to the true wave reception time can be estimated by one propagation calculation. be able to. As a result, the propagation delay time can be determined with higher accuracy than using the instantaneous receiver velocity.

FIG. 13 is used as an example of confirming the effect of the first embodiment. FIG. 13 is a diagram showing an example of one-dimensional acceleration motion opposition. In FIG. 13, at time t=0, the distance between the transmitter and the receiver is 9000 m, the initial velocity of the receiver is 0 [m/s], and the acceleration is transmitted by the receiver. 8 [m/s ² ] in the direction away from the device.

14 is a table showing various values at each time in the example shown in FIG. 13 in Embodiment 1. FIG. In the text, norm symbols in formulas and tables are represented by absolute value symbols.

|P _r |[m] in the second row of the table is the position of the receiver at each time, that is, the true value of the distance between the transmitter and the receiver. |v _r | [m/s] in the third row of the table is the true value of the receiver velocity at each time. The τ _{true value} [s] in the fourth row of the table is the true value of the propagation delay time of the sound transmitted at each time. τ _{Comparative Example} [s] in the fifth row of the table is the value obtained by the method of Comparative Example 2 for the propagation delay time of the sound transmitted at each time. _{τreal 1} [s] in the sixth row of the table is the value obtained by the method of the first embodiment for the propagation delay time of the sound transmitted at each time.

Also, the D _{true value} [s] in the seventh row of the table is the true value of the Doppler coefficient of the sound transmitted at each time. _{Comparative example} D [s] on the eighth row of the table is a value obtained by estimating the Doppler coefficient of the sound transmitted at each time by the method of comparative example 2. _{Dactual 1} [s] in the 9th row of the table is a value obtained by estimating the Doppler coefficient of the sound transmitted at each time by the method of the first embodiment.

Here, when the sampling frequency fs=1 kHz and the block length Nb=fs[sample], the Doppler coefficient D is obtained using the equation (9) representing expansion and contraction of the block due to the delay error.

In this example, in estimating the propagation delay time τ, for example, when the _true value τ of the propagation delay time is 6.09920 [s] at time t = 0, the propagation delay time τ estimated in Comparative Example 2 _{The comparative example} is 6.09600 [s] and has an error of 3.20 [ms]. On the other hand, the propagation delay time _{τreal 1} [s] estimated by the method of the first embodiment is 6.09915 [s], and the error can be suppressed to 0.05 [ms].

Furthermore, in estimating the Doppler coefficient D, _{the true} value D of the Doppler coefficient is 0.96471, whereas the Doppler coefficient D estimated in Comparative _Example 2 is 0.96528. The Doppler coefficient D _{real 1} estimated by is 0.96474.

As a result, in frequency estimation, for example, when the transmission frequency is 1 kHz, at the estimated time t=0, the true value of 964.71 Hz is 965.28 Hz in Comparative Example 2, resulting in an error of about 11 Hz. . On the other hand, in the method of Embodiment 1, the frequency is 964.74 Hz, and the error can be suppressed to 0.03 Hz. In particular, in acoustic communication and active sonar pseudo signal generation, where the accuracy of Doppler coefficient estimation is important, it is significant in that it can reproduce intended frequency changes.

The propagation delay time calculation device 1 of Embodiment 1 has a first propagation calculation means 21 , an average speed calculation means 22 , a propagation delay time estimation means 23 and a second propagation calculation means 24 . The first propagation calculation means 21 obtains a provisional propagation delay time using a calculation model predetermined for the position of the transmitter and the position of the receiver at time t. The average velocity calculation means 22 obtains the receiver average velocity, which is the average velocity of the receiver during the provisional propagation delay time. The propagation delay time estimating means 23 calculates an estimated propagation delay time from the receiver average velocity and the transmitter position and receiver position at time t. The second propagation calculation means 24 calculates the propagation delay time from the position of the transmitter at time t to the position of the receiver predicted by the estimated propagation delay time using a calculation model.

The first embodiment is a comparative example in which the larger the acceleration of the movement of the wave receiver or the longer the distance between the transmitter and the receiver, the more possible wave reception times must be considered. Compared to 1, the effect of suppressing the amount of calculation is large. On the other hand, in the first embodiment, the estimation accuracy can be kept higher than in the comparative example 2 in which the estimation error of the propagation delay time due to the change in the received wave velocity during the passage of the propagation delay time is large.

Embodiment 2.
The second embodiment is to calculate the propagation delay time more accurately. In the second embodiment, the same components as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The configuration of the propagation delay time calculation device according to the second embodiment will be described. Since the overall configuration of the propagation delay time calculation device 1 of Embodiment 2 is the same as the configuration shown in FIG. 5, detailed description thereof will be omitted. 15 is a functional block diagram showing a configuration example of a control unit of the propagation delay time calculation device according to Embodiment 2. FIG.

The control unit 4a has receiver position interpolation means 25, delay error calculation means 26 and determination means 27 in addition to the means shown in FIG. In Embodiment 2, the storage unit 3 does not have to have the wave receiver speed memory 33 shown in FIG.

Receiver position interpolation means 25 receives as input the provisional propagation delay time, which is the provisional propagation delay time output from first propagation calculation means 21, and the information in receiver position memory 32, and calculates Interpolation processing is performed on the position of the wave receiver to calculate an interpolated position of the wave receiver, which is the position of the wave receiver after the provisional propagation delay time has elapsed. The receiver position interpolation means 25 outputs the calculated interpolated receiver position to the average velocity calculation means 22 . The average velocity calculator 22 receives the interpolated receiver position output from the receiver position interpolator 25 and calculates the receiver average velocity. The average velocity calculator 22 outputs the calculated receiver average velocity to the propagation delay time estimator 23 .

The propagation delay time estimating means 23 receives the receiver average velocity output from the average velocity calculating means 22, the information in the transmitter position memory 31, and the information in the receiver position memory 32, and calculates the estimated propagation delay time. calculate. The propagation delay time estimation means 23 outputs the calculated estimated propagation delay time to the second propagation calculation means 24 and the delay error calculation means 26 . When the estimated propagation delay time output from the propagation delay time estimation means 23, the information in the transmitter position memory 31, and the information in the receiver position memory 32 are input to the second propagation calculation means 24, A propagation delay time is calculated in the same manner as in the first embodiment. The second propagation calculation means 24 outputs the calculated propagation delay time to the delay error calculation means 26 .

When the estimated propagation delay time output from the propagation delay time estimating means 23 and the propagation delay time output from the second propagation calculating means 24 are inputted, the delay error calculating means 26 calculates a delay time difference and calculates a delay. It outputs the time difference and the propagation delay time to the determination means 27 .

A judging means 27 judges the validity of the precision of the propagation delay time calculated by the second propagation calculating means 24 . Specifically, when receiving the delay error and the propagation delay time output from the delay error calculation means 26, the determination means 27 determines whether or not the delay error satisfies a predetermined condition. If the delay error does not satisfy the condition, the determination means 27 outputs the propagation delay time to the receiver position interpolation means 25 as a new provisional propagation delay time. Until the delay error satisfies the condition, the determination means 27 repeats the process of outputting to the receiver position interpolation means 25 in order to update the propagation delay time as the provisional propagation delay time. On the other hand, if the delay error satisfies the condition, the determination means 27 stores the propagation delay time in the propagation information of the propagation information memory 34 .

First propagation calculation means 21, receiver position interpolation means 25, average velocity calculation means 22, propagation delay time estimation means 23, second propagation calculation means 24, delay error calculation means 26 and determination means 27 are: , while updating the transmission time index i, the processing is repeated until the final transmission time index L.

Next, the operation of the propagation delay time calculation device 1 according to the second embodiment will be explained. FIG. 16 is a flow chart showing the procedure of the propagation delay time calculation method according to the second embodiment. As in the case of the first embodiment, the second embodiment also takes the propagation of sound waves as an example, and simulates the received waveform of the wave receiver in a situation where the position vectors of the wave transmitter and the wave receiver change over time. Consider signal generation.

The processing of steps S201 and S202 shown in FIG. 16 is the same as steps S101 and S102 described with reference to FIG. 12 in Embodiment 1, so detailed description thereof will be omitted. 16 are the same as steps S104 and S105 described with reference to FIG. 12 in Embodiment 1, so detailed description thereof will be omitted.

In step S203, the receiver position interpolation means 25 performs receiver position interpolation processing as follows in order to obtain the propagation delay time with higher accuracy. The receiver position interpolation means 25 uses the information in the receiver position memory 32 to apply, for example, Equation (10), which is linear interpolation, to the provisional propagation delay time τ'(i) that is the processing result of step S202. is used to determine the position of the receiver considering the provisional propagation delay time. This receiver position corresponds to the interpolated receiver position. In Expression (10), floor[·] means a round-down operation.

In step S204, the average velocity calculation means 22 performs receiver average velocity calculation processing as follows. Using the following equation (11), the average velocity calculation means 22 calculates the distance from the receiver position at the transmission time to the receiver position calculated by equation (10) as the provisional propagation delay time τ' ( By dividing by i), the receiver average velocity _vr is calculated.

In step S207, the delay error calculation means 26 performs delay error calculation processing as follows. The delay error calculator 26 calculates the delay error Δτ using equation (12). Specifically, the delay error calculation means 26 calculates the difference between the receiver position p _r (i+round[τ̂(i)/Δt]) corrected by the estimated propagation delay time τ̂(i) and the transmitter position. and the estimated propagation delay time τ^(i) is calculated as the delay error Δτ.

In step S208, the determination unit 27 compares the delay error Δτ with a preset delay time accuracy threshold T to determine whether the delay error Δτ is smaller than the delay time accuracy threshold T. If Δτ≧T as a result of the determination in step S208, the determining means 27 determines that the estimation accuracy of the propagation delay time τ(i) is insufficient. Then, the determining means 27 updates the propagation delay time τ(i) whose accuracy is improved from the first calculated provisional propagation delay time τ'(i) as a new provisional propagation delay time τ'(i). Then, the determination means 27 outputs the updated provisional propagation delay time τ′(i) to the receiver position interpolation means 25 . Until the determination condition of step S208 is satisfied, the determining means 27 repeats the process of updating the provisional propagation delay time to a more accurate value.

On the other hand, if Δτ<T as a result of the determination in step S208, the determining means 27 determines that the propagation delay time has sufficiently approached the true value. Then, the determination means 27 writes the propagation delay time τ(i) into the propagation information of the propagation information memory 34 .

The effect of the propagation delay time calculation method by the propagation delay time calculation device 1 of the second embodiment will be described. As described with reference to FIG. 16, in the second embodiment, the estimated propagation delay time is estimated even if one or both of the transmitter and receiver are in any motion including acceleration motion. Using the error from the propagation delay to the position of the receiver, the estimation of the propagation delay time is repeated until the set conditions are met. Therefore, although the calculation cost is higher than that of the method of the first embodiment, the calculation cost is lower than that of the comparative example 1, and the propagation delay time can be estimated with higher accuracy than that of the first embodiment.

As an example of confirming the effect of the second embodiment, FIG. 13 is used as in the first embodiment. 17 is a table showing various values at each time in the example shown in FIG. 13 in Embodiment 2. FIG. In the text, norm symbols in formulas and tables are represented by absolute value symbols.

|P _r |[m] in the second row of the table is the position of the receiver at each time, that is, the true value of the distance between the transmitter and the receiver. |v _r | [m/s] in the third row of the table is the true value of the receiver velocity at each time. |v _r | _{true value} [m/s] in the fourth row of the table is the true value of the average speed of movement of the receiver until the sound transmitted at each time is received. |v _r | _{Actual 1} [m/s] in the fifth row of the table indicates the average speed of movement of the receiver until the sound transmitted at each time is received. This is the value estimated by the method. |v _r | _{Ex 2} [m/s] in the sixth row of the table indicates the average speed of movement of the receiver until the sound transmitted at each time is received. This is the value estimated the first time before the repetition of the determination process of No. 2 (step S208).

The τ _{true value} [s] on the 7th row of the table is the true value of the delay time of the sound transmitted at each time. _{τreal 1} [s] in the eighth row of the table is the value obtained by the method of the first embodiment for the delay time of the sound transmitted at each time. _{τreal 2} [s] in the 9th row of the table is the value obtained by the method of the second embodiment for the delay time of the sound transmitted at each time.

The D _{true value} on the 10th row of the table is the true value of the Doppler coefficient of the sound transmitted at each time. D _-1 on the 11th row of the table is a value obtained by estimating the Doppler coefficient of the sound transmitted at each time by the method of the first embodiment. D _{-actual 2} on the 12th row of the table is a value obtained by estimating the Doppler coefficient of the sound transmitted at each time by the method of the second embodiment.

Here, when the sampling frequency fs=1 kHz and the block length Nb=fs[sample], the Doppler coefficient D is obtained using the equation (9) representing expansion and contraction of the block due to the delay error. Further, the calculation is made with the threshold T=1 ms.

In the second embodiment, the position of the wave receiver is determined more accurately than in the first embodiment by using equation (10) using linear interpolation. Therefore, for example, at time t=1, the accuracy of the estimation of the receiver average velocity is improved by 12.4 mm/s.

In estimating the propagation delay time τ, for example, when the true value τ _{true value} is 6.09920 s at time t=0, the propagation delay time τ _{real 1} estimated by the method of Embodiment 1 is 6.09915 s, The error can be suppressed to 0.05 ms. On the other hand, the propagation delay time _{τreal 2} estimated by the method of Embodiment 2 is 6.09921 s, which can be suppressed to an error of 0.01 ms.

Furthermore, in the estimation of the Doppler coefficient D, the true value D _{true value} is 0.96471, whereas the Doppler coefficient D _{real 1} estimated by the method of Embodiment 1 is 0.96474. The Doppler coefficient D _{real 2} estimated by the method of No. 2 is 0.96470.

As a result, in frequency estimation, for example, when the transmission frequency is 1 kHz, at the estimated time t=0, the true value of 964.71 Hz is 964.74 Hz with the method of Embodiment 1, and the error is 0.74 Hz. 03 Hz. On the other hand, in the method of Embodiment 2, the frequency is 964.70 Hz, and the error is suppressed to 0.01 Hz.

At time t>0, the method of Embodiment 1 tends to increase the estimation error gradually. On the other hand, according to the second embodiment, the estimation error is suppressed by performing the additional propagation calculation once. For this reason, repeating the calculation of the average received wave velocity using the position of the receiver by interpolation and the propagation calculation by the estimation error judgment as in the second embodiment can obtain the propagation delay time with high accuracy. Effective when necessary.

In the first and second embodiments described above, the case of a single information processing device has been described, but the arithmetic device that calculates the propagation delay time may be a system having a plurality of information processing devices. 18 is a block diagram showing another configuration example of the propagation delay time calculation device according to Embodiment 1. FIG.

The propagation delay time calculation system 10 shown in FIG. 18 has information processing devices 101-103. Information processing apparatuses 101 to 103 are connected to each other via a network 200 such as the Internet. For example, the information processing device 101 has the storage unit 3 shown in FIG. has the propagation delay time estimation means 23 and the second propagation calculation means 24 shown in FIG. In this case, since the arithmetic processing necessary for executing the propagation delay time calculation method of the first embodiment is distributed among the plurality of information processing devices 101 to 103, the load on each information processing device is reduced, and the arithmetic processing speed can be increased.

It should be noted that although the case where the device described in the first embodiment is applied to the system has been described with reference to FIG. 18, the device described in the second embodiment may be applied to the system. Also, although FIG. 18 shows a case where there are three information processing apparatuses, the number of information processing apparatuses is not limited.

(Usage form)
In the first embodiment, the propagation of sound has been described as an example, but it is also applicable to waves, for example, radar.

In Embodiment 1, in the first propagation calculation processing in step S102 and the second propagation calculation processing in step S105 shown in FIG. 12, Bellhop model sound ray calculation was described as an example. If the propagation delay time can be obtained, another acoustic ray model or a wave model such as a normal mode with improved simulation accuracy may be used at the expense of calculation speed.

In Embodiment 1, in the receiver average velocity calculation process of step S103 shown in FIG. If the length is about the length corresponding to the time τ' (i), even if it is not a rounding up operation (i ~ i + ceil [τ' (i) / Δt]), a rounding down operation (i ~ i + floor [τ' (i) /Δt]) or a rounding operation (i˜i+round[τ′(i)/Δt]).

In Embodiment 1, in the receiver average velocity calculation process of step S103 shown in FIG. is not limited to the method described in . For example, due to the trade-off between calculation cost and calculation accuracy, as described in step S204 shown in FIG. The receiver average velocity may be calculated from the delay time.

In the first embodiment, as a method of calculating the predicted position of the receiver, the case of referring to the receiver position information stored in the receiver position memory 32 and adopting the closest receiver position has been described. However, the interpolation positions described in the second embodiment may be adopted.

In the second embodiment, as a method of judging the validity of the accuracy of the propagation delay time, the propagation delay time from the transmitter position to the receiver position predicted by the provisional propagation delay time and the receiver average Although the case where the delay error from the estimated propagation delay time calculated from the velocity is used as the determination index has been described, the determination index is not limited to the delay error. Further, as a method of determining the validity of the accuracy of the propagation delay time, for example, the degree of change from the previous value of the delay error described above may be used. In this case, if the degree of change from the previous value of the delay error is greater than a predetermined threshold value, it is determined that the accuracy of the propagation delay time is inappropriate. Any decision index can be adopted as long as it is a decision index that can determine the validity of the accuracy of the propagation delay time.

In the second embodiment, the expression (10) for obtaining the position of the receiver was explained using floor [τ'(i)/Δt]. (i)/Δt] or ceil[τ′(i)/Δt] may be used.

In Embodiment 2, the average received wave position is obtained by linear interpolation, but another interpolation such as spline interpolation may be used depending on the trade-off between calculation cost and calculation accuracy, for example.

1 Propagation Delay Time Calculation Device 2 Input Section 3 Storage Section 4, 4a Control Section 5 Output Section 10 Propagation Delay Time Calculation System 11 Memory 12 CPU
21 first propagation calculation means 22 average velocity calculation means 23 propagation delay time estimation means 24 second propagation calculation means 25 receiver position interpolation means 26 delay error calculation means 27 determination means 31 transmitter position memory 32 receiver Position memory 33 Receiver velocity memory 34 Propagation information memory 101 Information processing device 102 Information processing device 103 Information processing device 200 Network

Claims (9)

Propagation delay time calculation for calculating a propagation delay time until a wave transmitted from the transmitter and the receiver arrives at the receiver at an arbitrary time when one or both of the transmitter and the receiver are moving a device,
first propagation calculation means for obtaining a provisional propagation delay time, which is a provisional propagation delay time, using a calculation model predetermined for the position of the transmitter and the position of the receiver at the time;
Average velocity calculation means for calculating an average velocity of the receiver, which is the average velocity of the receiver during the provisional propagation delay time;
Propagation delay time estimating means for calculating an estimated propagation delay time from the average velocity of the receiver and the position of the transmitter and the position of the receiver at the time;
a second propagation calculation means for calculating, using the calculation model, the propagation delay time from the position of the transmitter at the time to the position of the receiver predicted by the estimated propagation delay time;
A propagation delay time calculation device having The average speed calculation means is
using the interim propagation delay time as a time interval for calculating the receiver average velocity;
The propagation delay time calculation device according to claim 1. Receiver position interpolation means for performing interpolation processing on the position of the receiver at the provisional propagation delay time to calculate an interpolated position of the receiver, which is the position of the receiver after the provisional propagation delay time has elapsed. has
The average speed calculation means is
calculating the receiver average velocity by dividing the distance between the receiver position and the interpolated receiver position at the time by the provisional propagation delay time;
The propagation delay time calculation device according to claim 1. determining means for determining validity of accuracy of the propagation delay time calculated by the second propagation calculating means;
The determination means is
If it is determined that the accuracy of the propagation delay time is not appropriate, updating the propagation delay time as the provisional propagation delay time,
The average speed calculation means is
calculating the receiver average velocity based on the provisional propagation delay time updated by the determining means;
The propagation delay time calculation device according to any one of claims 1 to 3. The determination means is
A value based on the propagation delay time from the transmitter position to the predicted receiver position and the estimated propagation delay time calculated from the receiver average velocity is used as the validity determination index. do,
5. The propagation delay time calculation device according to claim 4. The determination means is
Using the degree of change of the determination index to determine the validity,
6. The propagation delay time calculation device according to claim 5. Propagation delay time calculation for calculating a propagation delay time until a wave transmitted from the transmitter and the receiver arrives at the receiver at an arbitrary time when one or both of the transmitter and the receiver are moving a system,
first propagation calculation means for obtaining a provisional propagation delay time, which is a provisional propagation delay time, using a calculation model predetermined for the position of the transmitter and the position of the receiver at the time;
Average velocity calculation means for calculating an average velocity of the receiver, which is the average velocity of the receiver during the provisional propagation delay time;
Propagation delay time estimating means for calculating an estimated propagation delay time from the average velocity of the receiver and the position of the transmitter and the position of the receiver at the time;
a second propagation calculation means for calculating, using the calculation model, the propagation delay time from the position of the transmitter at the time to the position of the receiver predicted by the estimated propagation delay time;
A propagation delay time calculation system having Propagation delay time calculation for calculating a propagation delay time until a wave transmitted from the transmitter and the receiver arrives at the receiver at an arbitrary time when one or both of the transmitter and the receiver are moving a method,
obtaining a provisional propagation delay time, which is a provisional propagation delay time, using a calculation model predetermined for the position of the transmitter and the position of the receiver at the time;
obtaining a receiver average velocity, which is the average velocity of the receiver at the provisional propagation delay time;
calculating an estimated propagation delay time from the receiver average velocity and the transmitter position and the receiver position at the time;
calculating, using the calculation model, a propagation delay time from the position of the transmitter at the time to the position of the receiver predicted by the estimated propagation delay time;
Propagation delay time calculation method having A computer that calculates the propagation delay time until a wave transmitted from the transmitter and the receiver at an arbitrary time arrives at the receiver when one or both of the transmitter and the receiver are moving,
first propagation calculation means for obtaining a provisional propagation delay time, which is a provisional propagation delay time, using a calculation model predetermined for the position of the transmitter and the position of the receiver at the time;
Average velocity calculation means for calculating an average velocity of the receiver, which is the average velocity of the receiver during the provisional propagation delay time;
Propagation delay time estimating means for calculating an estimated propagation delay time from the average velocity of the receiver and the position of the transmitter and the position of the receiver at the time;
and a second propagation calculation means for calculating, using the calculation model, the propagation delay time from the position of the transmitter at the time to the position of the receiver predicted by the estimated propagation delay time. program.

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