JP2011064677A - Water surface profile measuring device and water surface profile measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water surface profile measuring device that uses an observation device comparatively easy to be installed and managed and measures the water surface profile of sea or the like, and to provide a water surface profile method. <P>SOLUTION: The water surface profile measuring device includes a plurality of radars 10 that radiate pulse-like microwaves to the water surface, receive back scattered waves plural times at each of predetermined timings, detect the back scattered waves at each of a plurality of measuring points, and output a plurality of Doppler signals corresponding to the respective back scattered waves. The plurality of Doppler signals output by the respective radars 10 are used to generate information concerning the movement of water particles on the water surface at the plurality of measuring point provided in the radiation directions of the pulse-like microwaves of the radars, and the advancing direction of waves is determined based on the information indicating angles formed by the radiation directions of the pulse-like microwaves of the respective radars 10 and the advancing direction of waves. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an apparatus and a measurement method for measuring waves generated in the ocean, lake water, and the like.

  Information representing changes in the shape of the water surface, such as waves in the ocean and lake water, is important in the design and operation of ships, coasts, and offshore structures affected by the water surface. Therefore, various observations have been made to grasp the actual situation.

  As an example, there is a direct observation method using an ocean bottom ultrasonic wave height meter or an ocean buoy to observe ocean waves. In addition, there is a remote sensing method using a navigation radar, a synthetic aperture radar (SAR) mounted on an aircraft or an artificial satellite.

Chang-KyuRheem, Ocean Wave Observation by Continuous Wave Doppler Radar and Effect of Radar Irradiation Width on Wave Observation, Proceedings of the Japan Society of Marine Science and Technology, No.8, December 2008, pages 61 to 69 Chang-KyuRheem, Experimental Aquarium Wave Observation by Microwave Doppler Radar, Proceedings of Japan Society of Marine Science and Technology, No.6, December 2007, pages 65 to 73

  However, in the conventional observation, it is not easy to install and operate the observation equipment because it requires measuring equipment on the surface of the sea or requires an aircraft or an artificial satellite. It may also interfere with other marine activities such as fishing.

  Therefore, there is a demand for a technique for measuring the surface shape of the ocean or the like using an observation device that is relatively easy to install and operate. Non-Patent Documents 1 and 2 disclose methods relating to ocean waves using a microwave Doppler radar.

  The present invention has been made in view of the above circumstances, and provides a water surface shape measuring apparatus and a water surface shape measuring method capable of measuring the water surface shape of the ocean or the like using an observation device that is relatively easy to install and operate. Is one of its purposes.

The present invention for solving the problems of the above-described conventional example is a water surface shape measuring apparatus, which emits pulsed microwaves to the water surface, and sets backscattered waves of the emitted microwaves at a predetermined timing. A plurality of radars that receive a plurality of times, detect a backscattered wave at each of a plurality of measurement points for each pulsed microwave, and output a plurality of Doppler signals corresponding to each backscattered wave, A plurality of Doppler signals output from each of the radars generate information on the movement of water particles on the water surface at a plurality of measurement points arranged along the pulsed microwave radiation direction of each radar, and First direction specifying means for specifying an angle between the pulsed microwave radiation direction of each radar and the traveling direction of the waves based on the information on the movement of water particles on the water surface at a plurality of measurement points; Second direction specifying means for determining the traveling direction of the waves based on information representing the angle formed by the pulsed microwave radiation direction of the encoder and the traveling direction of the waves, and information on the movement of water particles on the water surface And information specifying the water surface shape is output based on the traveling direction information of the waves.
In addition, the water surface shape measurement apparatus according to one aspect of the present invention provides a center of the spatial distribution of signal intensity based on the time change of the signal intensity of the backscattered wave of the emitted microwave every time the microwave is emitted. Information representing the arrival time of the backscattered wave corresponding to the position, and information representing the arrival time of the backscattered wave corresponding to the center position of the plurality of spatial distributions of the signal intensities obtained by multiple times of microwave radiation From the difference, a means for generating and outputting information indicating fluctuations in the height of the water surface is further provided.

  Furthermore, the water surface shape measuring method according to one aspect of the present invention radiates a pulsed microwave to the water surface, receives the backscattered wave of the emitted microwave a plurality of times at predetermined timings, Detecting a backscattered wave at each of a plurality of measurement points for each pulsed microwave and outputting a plurality of Doppler signals corresponding to each backscattered wave using a computer connected to the plurality of radars, A plurality of Doppler signals output from each of the plurality of Doppler signals generated along the pulsed microwave radiation direction of each radar to generate water particle motion information on the water surface at a plurality of measurement points, and Generating information representing the angle between the pulsed microwave radiation direction of each radar and the traveling direction of the waves based on the information on the movement of water particles on the water surface at the measurement point; Determining the traveling direction of the waves based on information representing the angle between the pulsed microwave radiation direction of each radar and the traveling direction of the waves, and causing the computer to execute the motion of the water particles on the water surface. Based on this information and information on the traveling direction of waves, information for specifying the water surface shape is output.

  According to the present invention, since it is possible to measure from a position away from the surface of water to be observed, such as land or a fixed marine structure, the shape of the water surface can be measured using a device that is relatively easy to install and operate.

It is a block diagram showing the example of a structure of the water surface shape measuring apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the example of the wave used as the object of a measurement by the water surface shape measuring apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the example of the signal containing the backscattered wave which the water surface shape measuring apparatus which concerns on embodiment of this invention receives. It is explanatory drawing showing the freedom degree of the advancing direction of the wave which the water surface shape measuring apparatus which concerns on embodiment of this invention estimates. It is explanatory drawing showing the determination operation | movement of the advancing direction of a wave by the water surface shape measuring apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the example of a time change of the signal transmitted and received by the water surface shape measuring apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the example of arrangement | positioning of the measurement point used as the measuring object in each radar part of the water surface shape measuring apparatus which concerns on embodiment of this invention. It is a block diagram showing another structural example of the water surface shape measuring apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the example of the measurement result by the water surface shape measuring apparatus which concerns on embodiment of this invention. It is explanatory drawing showing the radiation direction of the microwave of the water surface shape measuring apparatus which concerns on embodiment of this invention.

  Embodiments of the present invention will be described with reference to the drawings. As illustrated in FIG. 1, the water surface shape measuring apparatus 1 according to the present embodiment includes a first radar unit 10 a, a second radar unit 10 b, and a calculation unit 20. Each radar unit 10a, b has the same configuration, that is, control unit 11, oscillator 12, transmission unit 13, distributor 14, phase shifter 15, reception unit 16, multipliers 17-1, 17-2, analysis. A unit 18 and an antenna 19 are provided.

  Here, the control unit 11 is a microcomputer having a memory that stores a program and also operates as a work memory, and controls each unit according to a predetermined program. The control unit 11 outputs a signal indicating that the microwave should be emitted to the transmission unit 13 at the timing of the microwave emission. In addition, every time a plurality of predetermined reception times (t1, t2,...) Elapse from the timing of the microwave radiation, an instruction to detect the output signal from the multiplier 17 is output to the analysis unit 18. To do.

  In the present embodiment, the control unit 11 causes the microwave to be radiated again after the time T has elapsed since the last microwave was radiated (where T is greater than the reception time).

  The oscillator 12 generates a microwave having a predetermined wavelength. In accordance with an instruction input from the control unit 11, the transmission unit 13 radiates through the antenna 19 at a predetermined timing for a predetermined time (transmission time). That is, the transmission unit 13 generates and outputs a microwave pulse signal at a timing instructed by the control unit 11.

  The distributor 14 distributes the microwave generated by the oscillator 12 and outputs it to the multiplier 17-1 and the phase shifter 15. The phase shifter 15 shifts the phase of the microwave output from the distributor 14 by π / 2 and outputs the phase to the multiplier 17-2.

  The receiving unit 16 receives a signal arriving at the antenna 19 and outputs the signal to the multiplier 17-1 and the multiplier 17-2.

  Multiplier 17-1 multiplies the signal output from receiver 16 by the signal output from distributor 14, and outputs an I-phase signal. The multiplier 17-2 multiplies the signal output from the receiving unit 16 and the signal output from the phase shifter 15 and outputs a Q-phase signal.

  The analysis unit 18 receives the signals output from the multipliers 17-1 and 17-2, and extracts a signal at a plurality of time points for each timing when an instruction is input from the control unit 11. That is, the output signals from these multipliers 17 change according to the elapsed time t after the pulsed microwave is emitted, as illustrated in FIG. A signal arriving at the time t from the time point t when the elapsed time from the time when the microwave was radiated is assumed to be c / 2t from the antenna 19 (because a round-trip is necessary). A signal based on the backscattering of the microwave at the measurement point is included with a position separated by 2) as a measurement point.

Therefore, signals at a plurality of elapsed times t 1, t 2,.
ri = c / 2ti (i = 1, 2,...)
The signal based on the backscattering of the microwaves at the measurement points that are far away from each other is included.

  Water particles near the surface of the ocean and lake water move under the influence of ocean currents, tidal currents, blowing currents, waves, and the like. The movement of water particles due to ocean currents, tidal currents, and insufflation currents in this area can be considered constant on a time scale of about a dozen minutes. On the other hand, the motion of water particles due to waves is a motion with a relatively short time period of several seconds to tens of seconds. Now, if a wave is illustrated in a cross section along the traveling direction, it will be as shown in FIG.

  In FIG. 2, water particles in the vicinity of the water surface move as indicated by white arrows in accordance with the wave phase. That is, it moves along the traveling direction at the highest wave height, and moves in the direction opposite to the traveling direction at the lowest wave height. In addition, when the waves travel along the wave traveling direction from a low wave height to a high wave height, the direction of movement of the water particles changes clockwise.

Now, when the wavelength of the emitted microwave is L and the initial phase is p0, the phase of the backscattered wave from the measurement point at the position r from the antenna 19 is
p = -4πr / L + p0
It becomes.

Therefore, the time change of the phase is dp / dt = − (4π / L) × dr / dt.
Thus, by knowing the temporal change of this phase, the water particle moving speed Vd = dr / dt at the measurement point can be calculated.

  The analysis unit 18 according to the present embodiment calculates each of the signals input from the multipliers 17-1 and 17-2 from the I-phase component and the Q-phase component at time t 1, t 2,. The phases p1, p2,... Of microwaves received at times t1, t2,... Are detected and stored in the memory.

  The analysis unit 18 uses the phases p1, p2,... Based on the backscattered wave from the next microwave (hereinafter, the phases stored in the memory are written as pA1, pA2,. The newly received phase is written as p1, p2,..., The phase time change pi−pAi (i = 1, 2,...) Is calculated, and this is divided by the microwave radiation interval T, and the coefficient − ( Multiply by (L / 4π) to obtain the water particle moving velocity Vdi (i = 1, 2,...).

  This Vdi represents the moving speed of water particles on the water surface separated from the antenna 19 by a distance ri = c / 2ti corresponding to the time ti (radiation direction component of microwave radiated from the antenna 19). As another method, Vdi may be obtained by using a short time Fourier transform (STFT) method from the I-phase component and the Q-phase component of a plurality of consecutive received signals.

  Next, the relationship between the wave traveling direction and the microwave radiation direction of the antenna 19 when focusing on one measurement point will be described. In addition, since the method of producing | generating the information of the water surface in one measurement point should just employ | adopt the method disclosed in the nonpatent literatures 1 and 2, it only gives only the outline | summary here.

  The wave is approximated by a cosine wave, where x is the traveling direction of the wave and y is the height direction of the wave. The cosine wave with displacement amplitude A and initial phase ε traveling in the x direction is

となる。

It becomes.

  The movement of water particles near the water surface is performed in the plane of xy, and the velocity is

である。

It is.

  As shown in FIG. 2, the antenna 19 is inclined at an angle θ from the vertically lower side, and the angle between the microwave radiation direction and the wave traveling direction (x) by the antenna 19 is represented by φ. The component of the moving speed of particles in the microwave radiation direction is

ただし、

However,

となる。

It becomes.

  As described above, if a plurality of microwaves are emitted, a plurality of measurement results Vd of the microwave radiation direction component of the moving speed of the water particles can be obtained by calculation. Assuming that it is equal to Vm, it is possible to obtain the frequency spectrum of the moving speed of water particles at each measurement point (the amplitude AωK and the phase k ri cosφ-ωt + α for each motion component of the angular frequency ω of the microwave radiation direction component Vm). Similarly, the analysis unit 18 also uses the STFT method to detect the amplitude AωK and the phase k ri cosφ − for each motion component of the angular frequency ω of the microwave radiation direction component Vm of the moving speed of the water particles at each measurement point. ω t + α (frequency spectrum) can be obtained.

  In this way, the amplitude AωK of the motion component of each angular frequency ω of the moving speed of the water particles at the measurement points S1, S2... At the distances r1, r2... From the antenna 19 in the microwave radiation direction and the phase k ri cosφ − ω t + α is obtained, and from these amplitude and phase, the analysis unit 18 uses the equations (4), (5), and (6) to radiate the microwave of the wave component of each angular frequency ω. The angle φ formed by the direction and the wave traveling direction, the displacement amplitude A, and the initial phase ε are obtained.

  Since general waves can be expressed as the superposition (sum) of cosine waves shown in equation (1), the analysis unit 18 determines the height yi (wave height) of the water surface at the measurement points S1, S2,. This is expressed by the angle φ formed by the microwave radiation direction of the wave component of each angular frequency ω and the wave traveling direction, the displacement amplitude A, and the initial phase ε.

  Here, the angle φ between the microwave radiation direction and the wave traveling direction of the wave component of each angular frequency ω is the measured value and the theoretical value k dr of the phase difference between the measurement points having different distance dr Calculated from the relationship with cosφ.

  However, this alone has the following degrees of freedom in the direction of the waves. That is, the analysis unit 18 here observes the component in the microwave radiation direction by one antenna 19 and calculates the angle φ formed by the wave traveling direction and the microwave radiation direction. Therefore, as shown in FIG. 4, is there a wave traveling direction at an angle shifted by φ clockwise relative to the microwave radiation direction (A), or shifted by φ counterclockwise relative to the microwave radiation direction? It is not known whether the wave has a traveling direction of the angle (B) (since the cosine of φ is involved in the calculation, the sign of φ is not clear). Since determination of the traveling direction of the waves is difficult by measurement with one antenna 19, the analysis unit 18 uses the information generated by the above processing (the amplitude A of the wave component of each angular frequency ω as information representing the water surface). , The initial phase ε, and the angle φ between the wave and the microwave radiation direction are output to the arithmetic unit 20.

  The calculation unit 20 is detected by each radar unit 10 from the analysis unit 18a of the first radar unit 10a (here, subscripts a and b are attached for distinction) and the analysis unit 18b of the second radar unit 10b. The amplitude A of the wave component of each angular frequency ω, the initial phase ε, and the angle φ formed by the wave and the microwave radiation direction are received.

  The calculation unit 20 includes information φa of the angle φ output from the analysis unit 18a of the first radar unit 10a, information φb of the angle φ output from the analysis unit 18b of the second radar unit 10b, and the micro of the first radar unit 10a. Using the wave radiation direction information fa and the microwave radiation direction information fb of the second radar unit 10b, processing for determining the wave traveling direction is performed as follows. Here, the microwave radiation direction information f of each radar is assumed to represent the azimuth with, for example, 0 in the north and π / 2 in the east. Further, it is assumed that fa> fb (FIG. 5).

  The computing unit 20 calculates fa−φa and fb + φb, and checks whether or not the absolute value X = | fa−fb−φa−φb | of these differences is below a predetermined threshold value Δ. If X is below the threshold value Δ, the wave traveling direction x (wave movement direction) is made parallel to fa−φa (or fb + φb). If X is not less than the threshold value Δ, the wave traveling direction x is parallel to fa + φa (or fb−φb). Note that X = | fa−fb−φa−φb | and Y = | fa−fb + φa + φb | are compared, and when X <Y, the wave traveling direction x is parallel to fa−φa (or fb + φb), and X When> Y, the wave traveling direction x may be parallel to fa + φa (or fb−φb).

  As a result of the above processing, the computing unit 20 uses the amplitude A of the wave component of each angular frequency ω, the initial phase ε, and the angle formed by the wave and the microwave radiation direction of each antenna 19a, b as information representing the water surface. φa, φb, and further, the wave traveling direction x is obtained, from which the wave direction, wave period, height, specific time and wave at a specific measurement point existing on the surface of the water area to be measured The phase is determined.

  The apparatus according to the present embodiment has the above configuration and operates as follows. The plurality of radar units 10 provided in the present embodiment are installed on land or a fixed offshore structure, respectively, so that microwaves can be emitted toward the water surface. Each radar unit 10 is arranged such that the radiation directions of the respective microwaves are different from each other. As an example, it is installed so that there is no microwave radiation direction of other radar devices within ± 15 ° from the radiation direction of microwaves of a certain radar device. As illustrated in FIG. 6, pulsed microwaves that last for a time of width τ are radiated at predetermined time intervals T. Further, a backscattered wave on the water surface of each pulsed microwave is received, and a backscattered wave is obtained every time a predetermined time t1, t2,. Here, each time the predetermined times t1, t2,... Elapse, the backscattered waves are backscattered waves on the water surface (measurement points) at distances r1, r2,. Hereinafter, as illustrated in FIG. 7, measurement points at distances r1, r2,... Along the radiation direction of the microwave radiated from the antenna 19a of the radar unit 10a are represented as measurement points A-1, A-2,. The measurement points at distances r1, r2,... Along the radiation direction of the microwave radiated from the antenna 19b of the radar unit 10b are represented as measurement points B-1, B-2,.

  Using a plurality of pulsed microwaves, the frequency spectrum of the water surface displacement is calculated from the backscattered waves at the measurement points (A-1, A-2, ...) at the distances r1, r2, ..., which respond to each pulse, using a method such as STFT. Ask. The method for obtaining the frequency spectrum of the water surface displacement corresponding to each measurement point can be performed by the methods disclosed in Non-Patent Documents 1 and 2.

  Further, the radar unit 10 specifies an angle formed by the microwave radiation direction and the wave motion direction based on the distance between the measurement points different from each other and the phase difference between the measurement points.

  Then, each radar unit 10 has a wave direction (wave angle, height, specific time, and wave at a specific measurement point) at each measurement point. Output each phase information.

  The arithmetic unit 20 identifies the wave moving direction by using information on the angle formed by the microwave radiation direction and the wave motion direction of each radar unit 10 among the above information output from the plurality of radar units 10. To do.

  As described above, in the present embodiment, there is no need to float the device on the water surface, and there is no need to use an aircraft or an artificial satellite, but there is a radar device deployed on land or a fixed offshore structure. The direction, wave period, height, and wave phase at a certain measurement point can be measured.

  The oscillator 12 and the transmitter 13 may be shared by the plurality of radar units 10 and used for signal emission from each radar in a time-sharing manner. In this case, the output signal of the transmitter 13 may be switched and output to the antennas 19a, b... Of each radar unit 10a, b.

  Furthermore, the radar unit 10 in the water surface shape measuring apparatus 1 of the present embodiment includes a control unit 11, an oscillator 12, a transmission unit 13, a distributor 14, a phase shifter 15, a reception unit 16, as illustrated in FIG. In addition to the multipliers 17-1 and 17-2, the analysis unit 18, and the antenna 19, a signal strength analysis unit 21 and a water level change amount calculation unit 22 may be included. In addition, about the thing which has the structure similar to what was already demonstrated, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  Here, the signal strength analysis unit 21 can be realized by a microcomputer having a memory that stores a program and also operates as a work memory. The signal intensity analysis unit 21 changes the intensity of the signal output by the reception unit 16 from the time when the transmission unit 13 starts to radiate microwaves (t0) until the time T elapses. Record. Specifically, at a predetermined time interval, a value obtained by digitizing the intensity of the signal output from the receiving unit 16 may be recorded in association with the elapsed time from t0. The contents of this record are conceptually illustrated as shown in FIG. As described above, the elapsed time from t0 corresponds to the distance to the water surface reflected by the microwave along the radiation direction of the microwave radiated by the antenna 19, and the time change of this signal intensity is It can also be regarded as a spatial distribution of microwave reception intensity.

  The signal strength analyzing unit 21 records the time α1 when the signal strength exceeds a predetermined threshold from t0 in the order of recording, and then the strength of the signal output by the receiving unit 16 falls below the predetermined threshold. Find time α2. Then, the time αM from the time t0 until the backscattered wave corresponding to the center position of the spatial distribution of signal intensity arrives is calculated as αM = (α1 + α2) / 2. The signal strength analysis unit 21 stores the calculated time value αM.

  The signal intensity analysis unit 21 performs the above processing every time the microwave is radiated, and the back scattered wave corresponding to the center position of the spatial distribution of the signal intensity from each time of the microwave radiation time t0 calculated each time. Times αM1, αM2,... Until arrival are obtained, and these values are output to the water level change amount calculation unit 22.

The water level change amount calculation unit 22 calculates the difference between αMi and αMi + k (i = 1, 2,..., K = 1, 2,...)
ΔL = c / (2 × αMi + k) −c / (2 × αMi)
And Here, the value of k may be determined in advance. Further, the water level change amount calculation unit 22 uses the depression angle θ in the microwave radiation direction from the antenna 19 (see FIG. 10), and the change amount of the water level between the time point represented by αMi and the time point represented by αMi + k. ΔH is calculated and output as follows.
ΔH = ΔL · cos θ

Here, from t0, a time α1 when the signal strength exceeds a predetermined threshold value and a time α2 when the signal strength output from the receiving unit 16 falls below the predetermined threshold value are found. The average time is the center position of the spatial distribution. However, the present invention is not limited to this, and the water level change amount calculation unit 22 determines, for example, the arrival time of the peak of the signal intensity (distance corresponding to the arrival time) as the center position of the spatial distribution. It is good. In this case, assuming that the time from the microwave radiation start time t0 of each time (i-th) to the arrival of the peak is αMi,
ΔL = c / (2 × αMi + k) −c / (2 × αMi)
Ask for.

  That is, in the present embodiment, the time variation of the intensity of the backscattered wave signal on the water surface of the pulsed microwave (which continues for time τ) radiated at a predetermined time interval T (after microwave radiation) , The signal intensity of the backscattered wave every time a predetermined time t1, t2,. Of the time variations of the signal intensity of the backscattered wave corresponding to multiple times of microwave radiation, the reference time of each time at the time corresponding to each other (for example, the microwave radiation start time as described above may be used. And the time elapsed from the end of the microwave emission). Here, the time points corresponding to each other may be, for example, the time points of arrival of the backscattered waves corresponding to the center position of the spatial distribution of signal intensity.

Then, using the difference ΔL of the center position of the spatial distribution of the signal intensity obtained corresponding to the multiple times of microwave radiation and the depression angle θ in the direction of microwave radiation from the antenna 19, the change amount ΔH of the water level is ΔH = ΔL · cos θ
As and output.

  The information on the amount of change in the water level is output to the calculation unit 20, and the calculation unit 20 may output information on the amount of change in the water level together with the information indicating the water surface.

DESCRIPTION OF SYMBOLS 1 Water surface shape measuring device, 10 Radar part, 11 Control part, 12 Oscillator, 13 Transmission part, 14 Divider, 15 Phase shifter, 16 Reception part, 17 Multiplier, 18 Analysis part, 19 Antenna, 20 Calculation part, 21 Signal strength analysis unit, 22 Water level change calculation unit

Claims (3)

A pulsed microwave is emitted to the water surface, and the backscattered wave of the emitted microwave is received a plurality of times at predetermined timings, and the backscattering is performed at a plurality of measurement points for each pulsed microwave. Equipped with multiple radars that detect waves and output multiple Doppler signals corresponding to each backscattered wave,
A plurality of Doppler signals output from each of the plurality of radars generate information on the movement of water particles on the water surface at a plurality of measurement points arranged along the pulsed microwave radiation direction of each radar. First direction specifying means for specifying an angle formed between the pulsed microwave radiation direction of each radar and the traveling direction of the waves based on the information on the movement of water particles on the water surface at the plurality of measurement points;
Second direction specifying means for determining the traveling direction of the waves based on information representing an angle formed between the pulsed microwave radiation direction of each radar and the traveling direction of the waves;
A water surface shape measuring device characterized by outputting information for specifying a water surface shape based on information on the movement of water particles on the water surface and information on the traveling direction of waves.   The water surface shape measuring apparatus according to claim 1, wherein each time the microwave is radiated, based on a temporal change in the signal intensity of the backscattered wave of the radiated microwave, the signal is measured at the center position of the spatial distribution of the signal intensity. Information indicating the arrival time of the corresponding backscattered wave is obtained, and the difference between the information indicating the arrival time of the backscattered wave corresponding to the center position of the plurality of spatial distributions of the signal intensities acquired by the multiple times of microwave radiation. The water surface shape measuring device further comprising means for generating and outputting information representing fluctuations in the height of the water surface. A pulsed microwave is emitted to the water surface, and the backscattered wave of the emitted microwave is received a plurality of times at predetermined timings, and the backscattering is performed at a plurality of measurement points for each pulsed microwave. Using a computer connected to multiple radars that detect waves and output multiple Doppler signals corresponding to each backscattered wave,
A plurality of Doppler signals output from each of the plurality of radars generate information on the movement of water particles on the water surface at a plurality of measurement points arranged along the pulsed microwave radiation direction of each radar. Generating information representing an angle formed between the pulsed microwave radiation direction of each radar and the traveling direction of the waves based on the information on the movement of water particles on the water surface at the plurality of measurement points;
Determining the traveling direction of the waves based on information representing the angle formed between the pulsed microwave radiation direction of each radar and the traveling direction of the waves;
The water surface shape measuring method characterized in that the computer is executed to output information for specifying the water surface shape based on the information on the movement of the water particles on the water surface and the information on the traveling direction of the waves.

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