JPS5825206B2 - Drifting buoy position measurement method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a technique for measuring the position of a drifting buoy, and more particularly to a method and apparatus for measuring the position of a drifting buoy, which is characterized by the angle measurement used in the three-point diagonal method.

Background of the Invention This invention is based on the conventional practice of controlling the discharge of heated wastewater discharged from thermal power plants, nuclear power plants, etc. into the ocean.

This is because, in order to preserve the marine environment, the behavior of thermal wastewater and the temperature changes that it causes to the sea must be adequately controlled.

For this reason, the above-mentioned management has conventionally been carried out using a drifting buoy equipped with a self-recording thermometer.

When using this drifting buoy, the boat should accompany the drifting buoy,
The reliability of this method was poor, as workers on the boat determined the position of the drifting buoy using landmarks on land.

Regarding the position measurement of this drifting buoy, for example, if we use the triangulation method used in the general field of surveying,
Surveying takes a relatively long time, and it is not possible to measure positions very continuously.

Another possibility is to emit radio waves from a drifting buoy and use these radio waves to measure the distance to the drifting buoy, but in this case it would be necessary to mount a dog-like device on the drifting buoy.
The size of the drifting buoy increases.

An increase in the size of the drifting buoy reduces its ability to follow the current well, resulting in deviation from the original purpose of the drifting buoy.

Due to these circumstances, the current situation is that the position of a drifting buoy is measured in batches.

In order to overcome this current situation, the patent applicant filed a patent application, Patent Application No. 55-21009 (Japanese Unexamined Patent Publication No. 56-1
A technique disclosed in ``Method for Measuring the Position of Drifting Buoy'' (Japanese Publication No. 17110) was proposed.

In summary, the method for measuring the position of a drifting buoy disclosed herein is a method of measuring the position of a drifting buoy using the principle of triangulation, and attempts to capture the angle measurement used in the triangulation method as a function of time. It is something to do.

That is, light sources are provided at two fixed positions having a predetermined distance between them and the drifting buoy, and light receiving devices whose light receiving direction rotates are provided at the two fixed positions.

The angle is then determined by the ratio of the time it takes for one light receiving device to detect the light source of the buoy and the light source of the other light receiving device to the time it takes for one light receiving device to rotate once.

However, it has been found that the techniques proposed above include problems that need to be further resolved.

That is, the drifting buoy is also provided with a light source, but in order to avoid undesirable effects from noise such as sunlight, it is necessary to increase the brightness of the light source provided on the drifting buoy.

However, since the batteries that serve as the power source for such light sources need to be mounted on the drifting buoy, there is a limit to their size, and the light sources must be kept on for a certain amount of time. Because of the necessity, the brightness of the light source cannot be made very high, and currently it is said that it is impossible to use it at a distance of about 100 meters or more.

Also, in order to measure the positions of several drifting buoys simultaneously, light modulation is necessary, but there is a limit to increasing the measurement accuracy and identifying the modulated light, so simultaneous measurements are possible. The number of drifting buoys was naturally limited.

Therefore, the main object of the present invention is to provide a method and apparatus for measuring the position of a drifting buoy that overcomes the above-mentioned problems.

This invention is based on the premise that there are three fixed positions A.

B and C are determined, and a predetermined distance d1 between fixed positions A and B is determined.
, the predetermined distance d2 between the fixed positions B and C, and the angle BDA defined by the drifting buoy position and the fixed positions A and B (
=α) and the angle BDC (=β) defined by the drifting buoy position and the fixed positions B and C, the drifting buoy position is measured by the three-point double angle method.

In summary, the method of the present invention can be summarized as follows:
, B, and C are provided, and the light beams emitted from these light sources are set to be parallel to each other and rotate in the same direction at a constant speed.A light receiving device is provided on the drifting buoy, and the light receiving device is set to the drifting buoy. The device is configured so that the emitted light beams from each of the fixed positions A, B, and C are sequentially incident on the device in the order of fixed positions A, B, and C, and the angle α is
is determined as a function of the time from when the light receiving device detects the light ray from fixed position A to when the light ray from fixed position B is detected, and the angle β is obtained when the light receiving device detects the light ray from fixed position B. It is characterized in that it is determined as a function of the time from when the light beam from the fixed position C is detected.

In summary, the device of this invention has three fixed positions A, B.
, C, and the light beams emitted from each light source are set to be directed parallel to each other and rotate in the same direction at a constant speed. It is equipped with a photoelectric conversion element that converts an optical signal received by the photoelectric conversion element into an electric signal, and a recording device that records the output signal from the photoelectric conversion element over time, and reads the time difference between the signals recorded on this recording device. By doing so, the angle α and the angle β are determined.

Other objects and features of the present invention will become more apparent from the detailed description given below with reference to the drawings.

FIG. 1 is an illustrative perspective view for explaining the basic principle of this invention.

Referring to FIG. 1, three fixed positions A, B, and C are determined at a location where the equipment can be easily installed, such as on land.

The distance between fixed positions A and B is dl, and fixed position B
, C is d2.

These distances d1. d2 is predetermined.

On the sea, the position of the drifting buoy 1 whose position is to be measured is the angle ADH (-α), the angle BDC (-β),
It can be determined when the distances d1 and d2 are determined.

This angle α. The feature of this invention lies in the way β is determined.

FIG. 2 is a geometrical illustration for explaining the angle measurement method.

FIG. 3 is a waveform diagram of the optical signal received by the light receiving device of the drifting buoy.

As shown in FIG. 1, rotating light source devices 2A, 2B, and 2C are provided at each fixed position A, B, and C, respectively.

Each rotating light source device 2A, 2B, 2C is configured as shown in FIG. 5, for example.

Explaining according to the rotating light source device 2A shown in FIG. 5, the light from the light source 3 becomes plane light when it passes through the lens 4, the slit 5, the lens 6, and the semicylindrical lens 7.

The semicylindrical lens 7 and the reflecting mirror 8 are rotated as a unit on a turntable 9.

The turntable 9 is rotated at a constant speed by a motor 10A.

Therefore, the light that has passed through the semicylindrical lens 7 is turned into a plane light extending perpendicularly to the water surface by the reflecting mirror 8, and is rotated by 360 degrees while being emitted in one direction.

On the other hand, the drifting buoy 1 is provided with a light receiving device 11 in a portion that stands out from the water surface.

The light receiving device 11 is composed of, for example, a phototransistor having a light receiving and photoelectric conversion function.

With reference to FIG. 2, an output light beam 12A emitted from the rotating light source devices 2A, 2B, and 2C located at each fixed position A, B, and C.
, 12B, and 12C are set to face parallel to each other, and are set to rotate in the same direction at a constant speed as described above.

By doing this, the order of the light beams that enter the light receiving device 11 of the drifting buoy 1 at the position is determined.

Become.

That is, the output light beams 12A, 12B, 12C, 12A,
... is always maintained.

FIG. 3 shows this state.

In FIG. 3, the symbols above each pulse indicate each fixed position A.

It corresponds to the rays from B and C.

In addition, each rotating light source device 2A seen from the drifting buoy 1 side,
Since the angles α and β of 2B and 2C do not exceed 180°, it always takes more than “the time required for half a rotation” to receive the output rays 12A, 12B, 12C and receive these rays during the next rotation. Since there is a large interval between the two, it is possible to easily identify which pulse corresponds to which outgoing light beam.

With reference to FIGS. 2 and 3, each rotating light source device 2A,
Outgoing light beams 12A and 12B of 2B and 2C.

The time required for 12C to make one rotation is TO, the time from when the light receiving device 11 receives the emitted light beam 12A until it receives the emitted light beam 12B is tl, and the time from when the light receiving device 11 receives the emitted light beam 12B until it receives the emitted light beam 12C. 12, angles α and β can be expressed as follows by geometric analysis in FIG.

. tlα −−X 360°・・・・・・・・・・・・
・・・・・・・・・・・・・・・(1) TO 2 β0−−X 360°・・・・・・・・・・・・・・・
・・・・・・・・・(2) TO In this way, the time difference between the received light pulse signals due to the emitted light beam received by the light receiving device 11 of the drifting buoy 1, and the time required for one rotation of the rotating light source device. The angles α and β were determined by the ratio of .

Next, a method of determining the position of the drifting buoy 1 from the angles α and β will be explained.

FIG. 4 is a geometrical illustration for explaining the position calculation method.

Distance d1 shown in FIG. d2° and angles α and β are the fourth
As shown in the figure.

For convenience of explanation, FIG. 4 shows fixed positions A, B,
Assume that C exists on a straight line.

In FIG. 4, the fixed position B is set as the origin, the y-axis is defined from there in the direction of the fixed position A, and the y-axis is defined perpendicularly to this y-axis in the direction of the sea from the fixed position B.

At this time, the coordinates of the position where drifting buoy 1 exists are (X,
y).

To find the position D(x, y), it is sufficient to find the distance r and angle θ shown in FIG.

The distance r corresponds to the straight-line distance between the fixed position B and the position of the drifting buoy 1.

The angle θ corresponds to the angle between the straight line BD and the y-axis.

The angle θ is determined by the following formula.

13□θ-Knee” Oil f1 Tracing Buddha-1991,, (3) x
(d1+d2) tanα−tanβ In this way, the angle θ is determined, and using this θ, the distance r is determined as follows.

cos' (α+θ) r=d ・□・・・・・・・・・・・・・・・・・・
(4) 1S1nα In the above manner, the position D (x, y) of the drifting buoy 1 is calculated from the angles α and β.

The drifting buoy 1 is equipped with a recording device and a power source (not shown) for recording electrical signals output from the light receiving device 11.

As the recording device, for example, a tape recorder is advantageously used.

Preferably, the recording device records the output signal from the light receiving device 11, and also records a clock pulse so that the time and the time difference between the pulse signals from the light receiving device 11 can be easily read later. recorded.

In this way, after recovering the drifting buoy 1, the data recorded in the recording device can be easily processed.

Such data processing is performed based on Equations 1 to 4 above, thereby making it possible to determine the locus of change in position of the drifting buoy 1 over time.

Furthermore, in addition to the information related to position measurement as described above, the recording device of the drifting buoy 1 can record data such as water temperature and water depth on separate tracks of the recording tape, so that a large number of various data can be recorded. can be processed or analyzed at the same time, which is convenient.

Rotating light source device 2A at each fixed position A, B, C.

The light source 3 used in 2B and 2C preferably uses a light source other than visible light that is not easily affected by sunlight, and is of high brightness.

For this purpose, for example, xenon lamps using a discharge of xenon gas are advantageously used, which have a high brightness and a strong spectrum in the near-infrared region.

In addition to this, it is preferable to use a filter in relation to the light incident on the light receiving section of the light receiving device 11 of the drifting buoy 1.

This filter is for removing the influence of natural light, and cuts incident light of wavelengths outside a certain band.

For example, when a xenon lamp is used as the light source 3 as described above, a filter is used that cuts wavelengths other than those around 8500λ.

More specifically, a solid filter using a semiconductor is advantageously used as the filter.

This solid filter has the feature that the filter range can be changed freely.

As mentioned above, in this invention, each rotating light source bag.

An important point is rotation control to maintain the rotation precision of the positions 2A, 2B, and 2C and their parallel relationship.

Here, it is known that in order to keep the angle measurement error within 0.001 rad, it is necessary to reduce the rotational unevenness of the rotating part to 0.0158% or less.

To do this, the motor must be carefully selected, but among the quartz lock direct drive motors for record players currently on the market, there is a rotational unevenness of 0.01.
It was found that there were some with a content of 5% or less and that they could be used conveniently.

Furthermore, each of the rotating light source devices 2A, 2B, and 2C is equipped with a motor, but in order to eliminate subtle errors in rotation between these motors, the rotation control of the three motors must be controlled in one.
This can be done using individual control parts.

FIG. 5 is a schematic diagram showing a preferred embodiment of a rotation control system for a rotating light source device.

FIG. 6 is a geometrical illustrative diagram that supplements the explanation of the positional relationship between the rotating light source device and the control center and the rotation control method shown in FIG. 5.

FIG. 1 is a waveform diagram of an optical signal received by a light receiving device of a control center.

As shown in FIG. 1, a control center 13 is installed at a suitable fixed position E on land.

The control center 13 includes each rotating light source device 2A.

It is equipped with a device for collectively controlling the rotation of the motors included in 2B and 2C.

The control center 13 also includes each rotating light source device 2.
A.

A light receiving device 14 receives the emitted light beams from 2B and 2C.
is provided.

The structure of the light receiving device 14 is almost the same as that of the light receiving device 11 provided on the drifting buoy 1, and includes, for example, a phototransistor 1.
Contains 5.

The difference from the light receiving device 11 on the drifting buoy 1 side is that this light receiving device 14 only needs to be provided at a fixed position E and configured to receive light rays from fixed positions A, B, and C. It may have some kind of specific directivity.

On the other hand, since it is not known in which direction the drifting buoy 1 will rotate, the light receiving device 11 of the drifting buoy 1 needs to be configured to be able to receive light from all directions.

This light receiving device 14 is also equipped with
Preferably, a filter 16 is provided.

FIG. 6 shows the positions of the rotating light source devices 2A, 2B, 2C and the control center 13.

The light receiving device 14 includes a rotating light source device 2C. 2B, 2A, 2
The respective output rays enter in the order of C, . . . .

Angle 11 between each rotating light source device 2C, 2B, 2A and the control center 13 in FIG. The time differences corresponding to yf2 are T1.yf2 in FIG. 7, respectively. It is T2.

By always keeping this time difference T1°T2 at a predetermined time and controlling the time TO required for one rotation of each rotating light source device 2A, 2B, 2C to be always constant, the rotating light source device 2A, 2B, 2C It is possible to maintain the rotation accuracy of each of the two and the mutual parallel relationship.

In order to control the rotation of the three rotating light source devices 2A, 2B, and 2C, one reference rotating light source device, for example, the rotating light source device 2B, is determined, and the other two rotating light sources are connected between this and the rotational light source device 2B. By controlling the rotation of the devices 2A and 2C, the final result is a fully rotating light source device 2A.

The rotations of 2B and 2C can be controlled all at once.

FIG. 5, which will be described below, and FIG. 8, which will be described later, illustrate rotation control of one of the rotating light source devices 2A with respect to the rotating light source device 2B based on this principle.

Therefore, although not specifically illustrated and explained, it will be understood that the rotation control for the other rotation control device 2C is also controlled in the same manner as for the rotation control device 2A.

Referring to FIG. 5, the rotating portion of the rotating light source device 2A is driven by a motor 10A.

Similarly, the rotating part of the rotating light source device 2B is driven by a motor 10B.

To control the rotation of both motors 10A and 10B, an output signal from a phototransistor 15 of a light receiving device 14 provided in a control center 13 is used.

This output signal has a waveform equivalent to that shown in FIG.

The output signal from the phototransistor 15 is transmitted to the amplifier circuit 17.
The signal is input to the time difference detection circuit 18, where it is amplified and input to the time difference detection circuit 18.

The time difference detection circuit 18 detects the time difference shown in FIG. T,,T2
are detected respectively.

Since only the rotational control of the motors 10A and 10B will now be explained with reference to FIG. 5, the following explanation will be made only about the time difference T2 related to this.

A signal related to the time difference T2 detected by the time difference detection circuit 18 is input to a comparison circuit 19.

On the other hand, the output from the time setting circuit 20 is input to the comparison circuit 19 .

In the time setting circuit 20, a predetermined value for the above-described time difference T2 is set in advance.

In the comparison circuit 19, the measured/actual time difference T2 from the time difference detection circuit 18 is compared with a predetermined value for the predetermined time difference T2.

A signal representing the result of this comparison is input to the servo circuit 21.

The servo circuit 21 is a rotating light source device 2B that serves as a reference for rotation.
a rotation control unit for rotating the motor 10B at a constant rotation speed independently of other motors;
It includes a rotation control section that controls the rotation of the motor 10A in a desired relationship with respect to the motor IOH, which is rotationally controlled independently in this manner.

A preferred example of such a servo circuit 21 will be described below.

FIG. 8 is a block diagram showing details of the servo circuit 21.

This servo circuit 21 includes a rotation control section 22A for the above-described motor 10A and a rotation control section 22B for the motor 10B.

The rotation control units 22A and 22B each include a motor 1.
Pickups 23A and 23B are included for detecting the rotational states of 0A and 10B.

The pickups 23A and 23B are each configured to include, for example, an optical or magnetic incremental encoder, and output a corresponding motor I.
A sine wave signal or pulse signal with a frequency corresponding to the rotational speed of the OA and 10B is derived.

The outputs of the pickups 23A and 23B are applied to phase comparator circuits 25A and 25B forming PLLs 24A and 23B, respectively.

The phase comparator circuits 25A and 25B are each PLL
Frequency dividers 528A and 28 that constitute 24A and 24B
Receive the output of B.

These phase comparison circuits 25A and 25B compare the phases of the output signals from the corresponding pickups 23A and 23B and the output signals from the frequency dividers 28A and 28B, and generate pulses according to the phase difference between the two inputs. A pulse signal having a width is derived.

The pulse signals from the phase comparator circuits 25A and 25B are applied to low-noise filters (LPF) 26A and 26B, respectively, and converted into DC voltages, and then used as control voltages for voltage controlled oscillators (VOC) 27A and 27B. Given.

The oscillation output signals from the vC027A and 27B are applied to the frequency dividers 28A and 28B, and also to the second phase comparison circuits 29A and 29B.

In this way, PLLs 24A and 24B are configured.

The rotation control units 22A and 22B are further provided with reference oscillators 30A and 30B, respectively.

These reference oscillators 30A and 30B each include, for example, a crystal oscillator, and the oscillation operation thereof is very stable.

The outputs of reference oscillators 30A and 30B are provided to variable frequency divider 31A and fixed frequency divider 31B, respectively.

The variable frequency divider 31A is provided with a signal from the time difference comparison circuit 19 that corresponds to the difference between the actual time difference and the set desired time difference, for example, as a digital signal, and the variable frequency divider 31A The frequency division ratio is set according to the detected difference.

On the other hand, a fixed frequency division ratio is set in advance in the fixed frequency divider 31B in order to control the motor 10B.

The outputs of frequency dividers 31A and 31B are provided as other inputs of phase comparison circuits 29A and 29B, respectively.

Therefore, phase comparator circuits 29A and 29B
Oscillation output signals from C27A and 27B and frequency divider 3
Compare the phase with the output signals from 1A and 31B, and
A signal corresponding to the phase difference between two input signals is derived.

Motor control circuits 32A and 32B are phase comparator circuit 2.
A predetermined motor drive voltage is generated according to the phase difference signals from 9A and 29B.

Motor 10B is frequency divided. Since the frequency divider 31B is a fixed frequency divider in which a constant frequency division ratio is set, constant speed control is performed at a rotation speed according to the frequency division ratio.

On the other hand, the motor 10A is controlled according to a signal from the time difference comparison circuit 19.

For example, if the motor 10A is rotating with respect to the other motor 10B in a state where the time difference is further advanced than the desired time difference, that is, in a state where the time difference is small, the time difference comparison circuit 19
detects that.

Then, depending on the degree of advance, the variable frequency divider 31A determines the desired time difference between the motors 10A and 10B.

Yes, the frequency division ratio is set.

The phase comparator circuit 29A compares the signal from the VCO 27A with the signal frequency-divided by a frequency division ratio that takes such a time difference into consideration. A phase difference signal is derived.

In such a case, the motor control circuit 32A provides a reverse rotation signal or a brake voltage to decelerate the motor 10A.

Therefore, the motors 10A and IOB are controlled to rotate stably with the time difference set by the time setting circuit 20.

The servo circuit 21 is a rotation control section 22A including such a PLL.

22B, frequency divider 28A.

The rotational speed of motors 10A and 10B can be controlled with a resolution that depends on the frequency division ratio of 28B, and the constant speed of rotation of motors 10A and 10B can be improved up to the frequency stability of reference oscillators 30A and 30B.

As described above, according to the present invention, the following effects are achieved.

The light emitted from the rotating light source device is directed in a specific direction, so there is no need to emit light all around the circumference.

Further, the rotating light source device is installed at a fixed position where power can be easily supplied.

For these reasons, high-intensity light can be easily emitted.

Therefore, the light can be transmitted further, and the range in which the position of the drifting buoy can be measured can be widened.

On the other hand, a drifting buoy only needs to be equipped with a light-receiving device and a recording device1, so its power source only needs to be small, and it does not increase the weight of the drifting buoy, eliminating its original function as a drifting buoy. It will not be done.

In particular, according to the device of the present invention, since the recording device is mounted on the drifting buoy, even if the number of such drifting buoys is increased without limit, the position of each drifting buoy cannot be determined later. It is easy to perform and provides highly accurate measurement results.

Further, the angle can be easily calculated from the data regarding the time difference recorded in the recording device in this way, and the position of the drifting buoy can be efficiently measured.

Although the rotational control of each rotating light source device has been described with reference to FIGS. 5 to 8, it is needless to say that it is not limited to this.

In other words, it is sufficient that the rotating light source devices are rotated with high rotation accuracy and in a parallel relationship with each other.

Therefore, a worker is assigned to each rotating light source device,
Each of these workers may communicate with each other and manually control the rotating light source device in their charge.
Of course, each rotation control device may be configured to rotate the three rotary light source devices as desired using a single rotation drive source, for example, via a chain.

[Brief explanation of drawings]

FIG. 1 is an illustrative perspective view for explaining the basic principle of this invention. FIG. 2 is a geometrical illustration for explaining the angle measurement method. FIG. 3 is a waveform diagram of the optical signal received by the light receiving device of the drifting buoy. FIG. 4 is a geometrical illustrative diagram for explaining the position calculation method. FIG. 5 is a schematic diagram showing a preferred embodiment of a rotating light source device and its rotation control system. FIG. 6 is a geometrical illustrative diagram that supplements the explanation of the positional relationship between the rotating light source device and the control center and the rotation control method shown in FIG. 5. FIG. 7 is a waveform diagram of an optical signal received by the light receiving device of the control center. FIG. 8 is a block diagram showing details of the servo circuit of FIG. 5. In the figure, A, B, and C are fixed positions, 1 is a drifting buoy, and 2
A, 2B, and 2C are rotating light source devices, 3 is a light source, 8 is a reflecting mirror, 9 is a turntable, and 10A. 10B and 10C are motors, 11 is a light receiving device, and 12A. 12B and 12C indicate outgoing light rays.

Claims (1)

[Claims] Thirteen fixed positions A, B, and C are determined, and a predetermined distance d1 between the fixed positions A and B, a predetermined distance d2 between the fixed positions B and C, and a drifting buoy position. From the angle BDA, (-α) defined by the fixed positions A and B, and the angle BDC (=β) defined by the drifting buoy position and the fixed positions B and C, the drifting buoy is calculated using the three-point double angle method. A method for measuring position, wherein a light source is provided at each of the three fixed positions A, B, and C, and the light beams emitted from each of the light sources are directed parallel to each other and rotate in the same direction at a constant speed. The drifting buoy is provided with a light receiving device, so that the light rays emitted from the fixed positions A, B, and C are sequentially incident on the light receiving device in the order of fixed positions A, B, and C, and the angle α is The angle β is determined as a function of the time from when the light receiving device detects the light ray from fixed position A to when the light ray from fixed position B is detected, and the angle β is calculated as a function of the time from when the light receiving device detects the light ray from fixed position B. 1. A method for measuring the position of a drifting buoy, characterized in that it is determined as a function of time until a light beam from a fixed position C is detected. 23 fixed positions A, B, and C are determined, and a predetermined distance d1 between fixed positions A and B, a predetermined distance d2 between fixed positions B and C, and a drifting buoy position and fixed positions A and B are determined. From the angle BDA (-α) defined by and the angle BDC (-β) defined by the drifting buoy position and fixed positions B and C,
This device continuously measures the position of a drifting buoy using the three-point double angle method, and includes light sources respectively installed at the three fixed positions A, B, and C, and the light beams emitted from each of the light sources are parallel to each other. The drifting buoy is configured to rotate in the same direction at a constant speed, and the drifting buoy includes: a light receiving section; a photoelectric conversion element that converts an optical signal received by the light receiving section into an electrical signal; and the photoelectric conversion element. A device for measuring the position of a drifting buoy, comprising: a recording device that records output signals from the buoy over time; and the angle α and the angle β are determined by reading the time difference between the signals recorded on the recording device. .