JP3358177B2 - Optical distance measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an installation distance between opposing stations between base lines in which an observation station is laid on an area such as the sea bottom or a lake bottom, and a fluctuation in light propagation speed based on a fluctuation in water temperature or the like is corrected. The present invention relates to an optical distance measuring apparatus that determines whether or not a distortion amount has occurred between opposing stations based on an arithmetic expression for calculating L.

[0002]

2. Description of the Related Art Ultrasonic rangefinders are installed at two places on the sea floor,
In the ultrasonic distance measurement method, which detects the expansion and contraction of the baseline from the change in the propagation time of the ultrasonic wave between the two, and uses it in the research data on the mechanism of earthquake occurrence, the ultrasonic wave propagation speed is affected by changes in the salt concentration, water temperature, etc. Because there are reasons such as fluctuation due to influence,
It is difficult to obtain a stable measurement result with an accuracy of about mm. For this reason, the present applicants have developed an optical distance measuring device that can accurately measure the propagation time using laser light instead of ultrasonic waves. We have already filed an application and obtained a patent (Japanese Patent No. 2906232)
issue).

[0003] Referring to FIG. 25, which conceptually shows a measuring line laid on the seabed, which comprises this optical distance measuring device, a laser beam transmitting station 903a and a number of relay stations 903b which constitute the optical distance measuring device. And the last-stage receiving station 903n
For example, as far as possible, the sea bottom E is selected and arranged at intervals of 30 m. Then, an optical pulse M ₁ generated from a laser light source (not shown) of the optical transmitting station 903a is
From the light transmitting window 905a to the light receiving window 90 of the next relay station 903b
And sending to 5b, it propagates the sending pulse M ₂ to the next repeater (not shown), the receiving station 903 of the last stage this way
The light is received by the light receiving window 905b of n. Transmitting station 903a, the relay station 903b, · · ·, and a pulse P obtained by photoelectrically converting the optical pulse M ₁ ··· M _n branched triangular prism at the final station 903N, ground observation station 9 via the cable 902
01 to the last receiving station 903 from the transmitting station 903a.
measuring the distribution設基line laser light propagation time T _t of up to n, it is to determine if it has an expansion and contraction of the base line as opposed to the propagation time T ₀ the previously measured.

As shown in FIG. 26A, two sets of measuring lines 910 and 911 composed of the optical distance measuring device constructed as described above are individually arranged so as to cross at right angles or obliquely across a tomogram 909. Then, the observation data in two directions collected by the measurement lines 910 and 911 is transmitted to the ground station by the transmission cable 919 via the transmission cables 907 and 908. Alternatively, FIG.
As shown in (B), two sets of measuring lines 912 and 913 of the optical distance measuring device are arranged on the seabed at right angles to each other across the tomography 909, and two directions collected by each measuring line 912 and 913 are shown. Of the observation data via transmission cables 915 and 916,
It is transported to the ground station by the transport cable 919.

[0005]

In the above-mentioned optical distance measuring apparatus, the propagation speed of light in water is not as high as that of ultrasonic waves, but changes according to changes in parameters such as the refractive index n and the water temperature. This indicates a value in which the propagation time of the light pulse between the base lines has changed. Therefore, if the parameter of the liquid such as the refractive index or the water temperature at the time of the measurement of the reference propagation time measured last time is not equal to the parameter of the liquid such as the refractive index or the water temperature at the next measurement, the fluctuation between the baselines will occur. Even if does not actually exist, there is a problem that it is erroneously recognized that the fluctuation has occurred between the baselines, and it is not possible to perform accurate observation, and because it is a method of observing only the propagation time between the baselines, There is a problem that it is not possible to recognize the physical state of the surrounding seawater such as the water pressure at the installation position of the optical distance measuring device.

Furthermore, in the system in which two sets of optically independent measuring lines are arranged orthogonally as described above, even if the crossing angle is changed or the measuring line distance is extended, the observation area is at most two sets. There is a problem in that the measurement data is limited from the direction in which the survey line is provided and the range of the extension of the survey line, and measurement data from a wider observation area in more directions from the survey line cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to eliminate the influence of fluctuations in the light pulse propagation speed in a liquid due to fluctuations in the refractive index. Based on the result of the difference between the true installation distance L between the opposing stations between the baseline measured at the time of the reference value measurement and the true installation distance L between the opposing stations at the time of measurement after a predetermined time has elapsed from the time of the reference value measurement. Identify the presence or absence of water bottom distortion between opposing stations,
An object of the present invention is to provide an optical distance measuring apparatus capable of obtaining a distortion amount based on a result of a ratio of a difference between the true installation distances between the opposite stations and an average value of the true installation distances between the opposite stations. .

According to a second aspect of the present invention, a short-time average correction amount for correcting an apparent fluctuation of the installation distance L between the opposite stations before the correction is defined as a plurality of short-time average correction amounts. The sum of the respective short-term average correction amounts <g> of the parameter g, or the sum of the respective short-time average correction amounts <g> of the plurality of parameters g at each station of the opposing station is added and divided by the number of opposing stations 2. When an “average value” is used, an optical distance measuring apparatus used as <δL ′ (parameter)> is provided.

A third aspect of the present invention provides a method for transmitting a laser beam from a transmission station at the head of a measurement line to a reception station at the end via a relay station, the propagation time of the laser beam measured at the time τ 1, Optical distance measurement using a new temperature correction method that checks the propagation time measured at τ2 and detects whether or not a fault has occurred even if the entire measurement line receives uniform temperature fluctuations. It is to provide a device.

According to a fourth aspect of the present invention, forward and backward measurement data in the light pulse propagation direction are obtained by arranging a return optical system in parallel to the forward optical system provided on the measurement line. Accordingly, an object of the present invention is to provide an optical distance measuring device that improves measurement accuracy.

According to a fifth aspect of the present invention, there is provided an optical distance measuring apparatus capable of laying an observation network having a surface spread on the water bottom by laying the measuring lines in parallel.
The invention of the present invention optically branches the transmission light pulse of the measuring line in multiple directions, and enables the laying of the measuring line in multiple directions by transmitting the light, thereby enlarging and forming the laying area of the measurement network on the water bottom. It is another object of the present invention to provide an optical distance measuring apparatus which enables measurement data to be obtained from a wider observation network.

According to a seventh aspect of the present invention, an observation station is laid at a position where a number of triangle vertices are formed on the water floor, each observation station receives a light propagation pulse from an adjacent station, and further transmits an optical signal to the adjacent station. Provided is an optical distance measuring device that enables the presence or absence of water floor distortion to be identified for each observation station by transmitting light and transmitting a propagation pulse to each other, and that can form a wider observation network. It is in.

According to the present invention, each branch pulse output from the stations installed opposite to each other is set as one set, and the time width ΔT of the set of branch pulses is counted by a plurality of clock signals having different frequencies. An object of the present invention is to provide an optical distance measuring device for obtaining an accurate measurement result by integrating the respective counting results.

According to a ninth aspect of the present invention, even when the water temperatures interposed between the stations constituting the measurement line are different from each other, the water temperature difference between the two opposing stations obtained at the time of the reference value measurement is not affected by the water temperature difference. The difference between the optical path length of one of the branched pulse lights that penetrates the water and the optical path length of the other branched pulse light that propagates through the optical fiber path of the distributed optical fiber thermometer between the two opposing stations, and the reference value measurement Based on the result of comparison with the difference between the two optical path lengths obtained at the time of measurement after a lapse of a predetermined time from the time, it is possible to accurately determine the presence or absence of a fault, or the presence or absence of the expansion and contraction of the fault, the presence or absence of crustal deformation. An object of the present invention is to provide an optical distance measuring device.

[0015]

Therefore, the invention of claim 1 is provided.
Is a transmission that transmits a light pulse through a fault at the bottom of the water
Station and a relay station that receives the light pulse and transmits the light pulse to the next station.
And the last receiving station that receives the light pulse from the relay station.
Are provided opposite to each other at predetermined intervals, and
From the propagation optical pulse propagated to the receiving station via the relay station
The optical pulse for observation is branched for each station from the
Luss row and each station detected by the sensor provided for each station
The refractive index of water around the installation, salinity, water temperature, water pressure, flow velocity,
And ground direction data via the transmission cable
At the time of reference value measurement
t₁And measurement after a lapse of a predetermined time from the measurement of this reference value.
Regular time t_TwoAt the photoelectric conversion
One set of pulses, one-way pulses between the opposing stations for each set obtained
Based on the propagation time width ΔT and the detected data,
For identifying the occurrence of horizontal distortion between opposing stations
An optical distance measuring device having a processing device, wherein the data
The processing device performs the measurement t₁And measurement time t_TwoAt the opposite
Refraction that gives an apparent variation to the installation distance L between stations
Rate, salinity, water temperature, water pressure, flow velocity, and flow direction parameters.
Data g is repeatedly detected N times, and the following equation (2) is used.
The measurement time t obtained by the following equation (1)₁And measurement
Time t_TwoVelocity of light pulse in water between opposite stations
At the time of measurement by substituting the pulse propagation time width ΔT between
t₁And measurement time t_TwoDistance between opposing stations before correction
L is calculated, and based on the following arithmetic expression (3),
N times of any one parameter g in one station
Measurement time t calculated by dividing the sum of repeated detection values by N₁
And measurement time t_TwoThe short-time average correction amount <g> in <
δL (parameter)> and is represented by the following arithmetic expression (3 ′).
When the above <δL (parameter)> is measured t₁And during measurement
t_TwoOf installation distance L between opposing stations before correction in
As a short-term average correction amount for correcting fluctuations in
According to the following equation (4), t₁Correction in
Previous installation distance L between opposing stations_(j)And short-time average correction amount <δL
(Parameter)>_t1True opposition after correction based on the sum of
The installation distance L between stations is obtained, and measured by the following arithmetic expression (4 ′).
Regular time t_TwoInstallation distance L before correction in_(j)And short
Time average correction amount <δL (parameter)>_t2Based on the sum of
To obtain the true installation distance L between the opposing stations after correction, and calculate
The above (measurement time t) shown in the formula (5A) or (5B)_TwoIn
Distance L between corrected opposing stations after correction_t2) From the value
Regular time t₁Corrected inter-station distance L after correction in_t1)
Of distortion between opposing stations based on the result of the difference
Is identified, and based on the following equation (5A)
And the above (at the time of measurement t_TwoTrue inter-station setup after correction in
Distance L_t2And the time of measurement t₁True after correction in
Installation distance L between opposing stations_t1) And the above (at the time of measurement t₁
And t_TwoCorrected inter-station distance L after correction in_t1Passing
And L_t2From the average value) or the following arithmetic expression (5B)
Based on the above (at the time of measurement t_TwoTrue pair after correction in
Installation distance L between stations_t2And the time of measurement t₁Correction in
True installation distance L between opposite stations_t1Value) and the above (measurement
Regular time t₁Corrected inter-station distance L after correction in _t1)
And the amount of distortion [ε (i, i +
1)]_t1 ^t2Is obtained. Operational expression (1): v = C₀/ N, where n is the measurement time t₁
And t_TwoMeasured refractive index of water of each station at C₀Is in a vacuum
Light speed (3 × 10⁸m / s) and v is t at the time of measurement₁And t
_TwoEquation (2): v × ΔT = L, where ΔT is the distance between the opposing stations.
Indicates the one-way propagation time width of the light pulse ofHere, <g> is an average value of N measurements of each parameter g,
That is, the short-time average correction amount of each parameter g, <δL (parameter
Parameter)> indicates the apparent installation distance L between opposing stations before correction
Short-term average correction amount for correcting the above fluctuation, i, (i
+1) is the i-th station, the (i + 1) -th station, δg_(j)And δ
L_(j)Indicates the j-th measured amount of N repeated detections. Equation (4): Measurement time t₁True opposite station at
Installation distance L = [L_t1 ^C(I, i + 1)] = (measurement time t
₁In the opposite station before correction [L_(j)(I, i
+1); t = t₁]) + (At the time of measurement t)₁Short time flat in
Average correction amount <δL (parameter)>_t1), Equation (4 '): t during measurement_TwoTrue opposition after correction at
Station installation distance L = [L_t2 ^C(I, i + 1)] = (at the time of measurement
t_TwoIn the opposite station before correction [L_(j)(I,
i + 1); t = t_Two]) + (At the time of measurement t)_TwoShort time in
Average correction amount <δL (parameter)>_t2), Equation (5A): [ε (i, i + 1)]_t1 ^t2≡ ｛(Measure
Time t_TwoOf the true installation distance between opposing stations [L_t2 ^C
(I, i + 1)])-(at the time of measurement t₁True after correction in
Installation distance [L_t1 ^C(I, i + 1)])｝ /
0.5 × ｛(at measurement t₁Between true opposing stations after correction at
Installation distance [L_t1 ^C(I, i + 1)]) + (measurement t_TwoTo
Corrected distance between opposing stations after correction [L_t2 ^C(I, i
+1)])｝, Equation (5B): [ε (i, i + 1)]_t1 ^t2≡ ｛(Measure
Time t_TwoOf the true installation distance between opposing stations [L_t2 ^C
(I, i + 1)])-(at the time of measurement t₁True after correction in
Installation distance [L_t1 ^C(I, i + 1)])｝ /
(At the time of measurement₁Corrected distance between opposing stations after correction
[L_t1 ^C(I, i + 1)]).

The invention of claim 2 is characterized in that the above-mentioned <δL (parameter
T)> is the time t₁And measurement time t_TwoCorrection in
Correct the apparent fluctuation of the installation distance L between the previous opposing stations
Any one of the above opposing stations as the short-time average correction amount for
Of each of the plurality of parameters g at each station
When adding the average correction amount <g> or when adding
Short-term average correction amount of arbitrary parameters g <
When the average value is obtained by adding g> and dividing by the number of opposing stations 2
Is represented as <δL ′ (parameter)>,
According to (4A), measurement time t₁Between opposing stations before correction
Installation distance L_(j)And short-time average correction amount <δL '(parameter
Ta)>_t1At the time of measurement based on the sum of₁After correction in
Is calculated as the true inter-station distance L, and the following equation (4B)
The measurement time t_TwoDistance between opposing stations before correction
L_(j)And short-time average correction amount <δL '(parameter)>
_t2At the time of measurement based on the sum of_TwoTrue after correction in
The installation distance L between the opposing stations is obtained, and the following arithmetic expression (5A) or
(5B) (at the time of measurement t_TwoTrue opposition after correction at
Station installation distance L_t2) Value (measurement time t₁Correction in
True installation distance L between opposite stations_t1) Based on the result of the difference
To identify whether or not distortion has occurred between opposing stations, and
Then, based on the following equation (5A),_TwoIn
Distance L between corrected opposing stations after correction_t2Value and measurement
Time t₁Corrected inter-station distance L after correction in_t1The value of the
Difference) and the above (at the time of measurement t)₁And t_TwoAfter correction in
True distance L between opposing stations_t1And L_t2Average)
Or based on the following equation (5B):_Two
Corrected inter-station distance L after correction in_t2The value of and
Measurement time t₁Corrected inter-station distance L after correction in_t1
(Difference in the value of₁True opposition after correction at
Station installation distance L_t1) And distortion generated between opposite stations
Quantity [ε (i, i + 1)]_t1 ^t2It is characterized by seeking. Equation (4A): t at the time of measurement₁True opposition after correction at
Station installation distance L = [L_t1 ^C(I, i + 1)] = (at the time of measurement
t₁In the opposite station before correction [L_(j)(I,
i + 1); t = t₁]) + (At the time of measurement t)₁Short time in
Average correction amount <δL '(parameter)>_t1), Equation (4B): t during measurement_TwoTrue opposition after correction at
Station installation distance L = [L_t2 ^C(I, i + 1)] = (at the time of measurement
t_TwoIn the opposite station before correction [L_(j)(I,
i + 1); t = t_Two]) + (At the time of measurement t)_TwoShort time in
Average correction amount <δL '(parameter)>_t2), Equation (5A): [ε (i, i + 1)]_t1 ^t2≡ ｛(Measure
Time t_TwoOf the true installation distance between opposing stations [L_t2 ^C
(I, i + 1)])-(at the time of measurement t₁True after correction in
Installation distance [L_t1 ^C(I, i + 1)])｝ /
0.5 × ｛(at measurement t₁Between true opposing stations after correction at
Installation distance [L_t1 ^C(I, i + 1)]) + (measurement t_TwoTo
Corrected distance between opposing stations after correction [L_t2 ^C(I, i
+1)])｝, Equation (5B): [ε (i, i + 1)]_t1 ^t2≡ ｛(Measure
Time t_TwoOf the true installation distance between opposing stations [L_t2 ^C
(I, i + 1)])-(at the time of measurement t₁True after correction in
Installation distance [L_t1 ^C(I, i + 1)])｝ /
(At the time of measurement₁Corrected distance between opposing stations after correction
[L_t1 ^C(I, i + 1)]).

According to a third aspect of the present invention, a fault at the bottom of the water is interposed.
And a transmitting station that transmits optical pulses and
A relay station that transmits light to the next station and an optical pulse from the relay station
The last receiving station that receives the light is installed facing each other at predetermined intervals.
Transmission line from the transmitting station to the receiving station via the relay station.
Light pulse for observation for each station from light pulse for propagation
And the photoelectric conversion pulse train is transmitted via a transmission cable.
To the ground station, and when measuring the reference amount τ₁In, photoelectric conversion
Pulse train, and the branching path between stations
One set of pulses, and each set of one-way pulse transmission
Calculate the seeding time width ΔT, add it, and refer to the propagation time T of the survey line
Determined as the propagation time, the reference propagation time T and the reference amount measurement time τ
₁Measurement time after_TwoIs compared with the propagation time T found in
Of horizontal strain on the bottom of the seabed
An optical distance measuring device equipped with a data processing device that identifies nothing
Each station has a temperature sensor to detect the water temperature around the installation.
A refractometer for detecting the refractive index n of the sensor and water,
The data processing device calculates the reference amount τ₁Initially measured water temperature of
Temperature t_As° C and the measured refractive index of water at
Folding ratio n_AsAnd the initial refractive index n_AsInto Equation 1 below
The propagation speed of the light pulse obtained by_Asage,
Furthermore, the measured pulse propagation time width Δ for each pair between the stations
T is the initial propagation time T_AsStored in the storage means as
At the time of measurement after measurement of reference quantity τ_TwoActual measured water temperature t_nActual measurement at ℃
Refractive index n_nInto the following equation 1 to calculate the light pulse propagation speed
Degree v_nTo calculate the measured pulse propagation time width ΔT for each set
Is the actual propagation time T_nMeasurement after the reference amount measurement.
Scheduled τ_TwoMeasured propagation time T_nAnd the propagation velocity v_nAnd the initial
Propagation speed v_AsAt the time of propagation calculated by substituting
Interval T_AsnAt the time of measurement after the reference amount measurement τ_TwoMeasurements in Japan
Sowing time T_nIs the initial temperature t _AsInitial propagation time T in ° C_As
Time T corrected for temperature_AsnAs a memory
At the time of reference value measurement τ₁Initial propagation time T_AsAnd temperature compensated propagation
Time T_AsnAnd horizontal distortion based on the comparison result.
Characterized in that it is configured to identify the presence or absence of only Equation 1: v = C₀/ N, where n is the reference amount measurement
Time τ₁And the measurement time τ after the reference amount measurement_TwoActual refraction of water
Rate, C₀Is the speed of light in a vacuum (3 × 10⁸m / s), v is
When measuring the calculated reference amount τ₁And measurement after the measurement of the reference amount.
Scheduled τ_TwoEquation 2: T, which indicates the initial propagation speed of the light pulse in the water._Asn= (V_n・ T_n) / V_As, Where v
_AsIs τ when measuring the reference amount. ₁Of light pulse in water measured at
Initial propagation velocity, v_nIs τ when measuring the reference amount.₁When measuring after
τ_TwoVelocity of light pulse in water at T_nIs
Scheduled τ_TwoMeasured propagation time, T_AsnIs the measurement time τ_TwoActual measurement
Sowing time T_nAt the time of the above-mentioned reference amount measurement τ₁Initial temperature t_As℃
Initial propagation time T_AsShows the propagation time with temperature compensation
You.

According to a fourth aspect of the present invention, there is provided, in parallel with the optical measuring system disposed in the direction of transmitting a laser beam from a transmitting station for transmitting an optical pulse, for each station on the measurement line, By arranging the optical measurement system in the direction opposite to the light transmission direction, a round-trip optical measurement system is formed on the measurement line, and the pulse propagation time width data detected by the round-trip optical measurement system and each station And transmitting the detection data from the sensor provided to the data processing device.

According to a fifth aspect of the present invention, there is provided a transmission line for transmitting a light pulse for propagation of a survey line, comprising: a plurality of survey lines comprising a train of a transmitting station, a relay station, and a receiving station positioned at the head of the survey line; , Laying so that the top transmitting station of each survey line is located in parallel,
The transmission line transmission station and the head transmission station of each measurement line are optically coupled so as to sequentially propagate the propagation light pulse branched from the propagation light pulse transmitted by the transmission line transmission station to the head transmission station of each measurement line. The transmitting optical pulse is transmitted from the head transmitting station of each path to the receiving station via the relay station, and is branched from the transmitting optical pulse branched from the head transmitting station, the relay station, and the receiving station of each path. A photoelectric conversion pulse train of optical pulses for observation and detection data from a sensor provided for each station are transmitted to a data processing device.

According to a sixth aspect of the present invention, the predetermined station on the measurement line is a branch station for branching the propagation optical pulse transmitted from the transmitting station, and the transmitting station positioned at the head of the branch station in a plurality of directions from the branch station. A plurality of branch paths including a station, a relay station, and a receiving station are laid in a branch, the propagation optical pulse is branched at the branch station, and light is transmitted from the head transmitting station of each branch path to the receiving station via the relay station. From the head transmitting station, relay station, and receiving station of each branch path, the photoelectric conversion pulse train of the observation light pulse branched from the propagation optical pulse, and the detection data of the sensor provided at each station of each branch path, It is characterized in that it is transmitted to a data processing device.

According to a seventh aspect of the present invention, an observation station is laid at each position forming the vertices of a large number of triangles on the water floor. By transmitting light to half of the observation stations, and receiving light propagation pulses transmitted from the other half of the adjacent observation stations, the observation stations can communicate with each other. An optical distance measuring device optically coupled to each other, comprising: an observation station and data transmitted and received between each observation station adjacent to the observation station; The detection data of the sensor provided in the observation station is transmitted to a data processing device.

According to an eighth aspect of the present invention, the above-described photoelectric conversion pulse train is transmitted to a ground station via a transmission cable, and a set of branch pulses between the stations installed opposite to each other is set as a pulse propagation time width ΔT for each set. , Counting by a plurality of clock pulses having different frequencies.

According to a ninth aspect of the present invention, there is provided a transmitting station for transmitting an optical pulse through a fault at the bottom of the water, a relay station for receiving the optical pulse and transmitting the light pulse to a next station, and a light from the relay station. Lay out a survey line that arranges the receiving stations at the final stage receiving the pulse at predetermined intervals, and connect the transmission cable from the ground station equipped with the data processing device to the transmitting station, the relay station, and the receiving station,
The transmission cable interposed between the stations facing each other, the distributed optical fiber thermometer which connects the stations to each other and additionally provided respectively, the reference measuring time t ₁ and the surveying Ordinary t ₁ from a predetermined time has elapsed after the measurement time t At the time of each measurement of ₂ , one branch optical pulse Sw branched from the one opposing station is transmitted from one opposing station to the other opposing station through the underwater optical path interposed between the opposing stations. At the same time, the other branch light pulse Sc is transmitted via the optical fiber optical path of the distributed optical fiber thermometer connecting the opposite stations, and the branch light pulse Sc and the reference light pulse Sp are measured and calculated in the other counter station. A first component signal received and detected by a first component detection unit of the device and indicating a phase difference between the two pulses Sc and Sp, a branch light pulse Sw and a reference light pulse S
p is received by the second component detection unit of the measurement and calculation device, and the reference amount measurement time t ₁ and the measurement time t indicating the phase difference with the second component signal indicating the phase difference between the two detected pulses Sw and Sp. ₂ is transmitted to the ground station via the transmission cable, and the ground station calculates the phase difference between the detection signal at the time of measurement of the reference amount t ₁ and the detection signal at the time of measurement t ₂ . Based on the comparison result, based on the comparison result, regardless of the difference between the water temperature between the opposing stations constituting the survey line and the water temperature between the other opposing stations, the presence or absence of a fault, expansion or contraction of the fault, crustal crust It is characterized by the presence or absence of a change.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a configuration of a laser light transmitting station of the present invention disposed on the sea floor,
(A) is a partial cross-sectional view of the transmitting station cut along the cutting line AA ′ of (B) and viewed from the direction of arrow P, (B) is a perspective view of the transmitting station shown in (A), FIG. 2 is a cross-sectional view schematically showing an internal configuration of a relay station of a survey line. FIG. 3 is a transmission cable for transmitting observation data from a transmitting station, a relay station, and a receiving station on the sea floor to a ground station, and one-side power supply. FIG. 4A is a sectional view of an optical amplifier provided in a transmitting station, a relay station, and a receiving station, and FIG. 4B is an erbium ( _Er ) -doped optical amplifier as an example of the optical amplifier. FIG. 5 shows a configuration diagram of a type optical fiber type optical amplifier, FIG. 5 shows a coupler for splitting optical power, (A) is a diagram of a front stage optical coupler disposed in a transmitting station, viewed from the side, and (B). Is a side view of the optical coupler disposed after the optical coupler preceding the transmitting station, and FIG. FIG. 6 is a side view of an optical coupler provided in a receiving station at the last stage of FIG. 6. FIG. 6 is a schematic cross section of each station configuration of the first set of measurement lines AA shown in FIG. FIG. 7 is an explanatory view of transmitting photoelectric conversion pulses transmitted from each station via an external cable while transmitting light to the final receiving station 10n via the relay station 10b... FIG. 7 is shown in FIG. FIG. 4 shows a schematic cross section of the configuration of each station of the second set of measurement lines BB. FIG. FIG. 8 is an explanatory diagram for transmitting a photoelectric conversion pulse transmitted from each station via an external cable. FIG. 8 is an overall arrangement diagram of the optical distance measuring apparatus according to the first installation method of the present invention, showing two sets of measurement lines. 9A is a block diagram in which line AA and line B are shown. Optical pulse train is sending from each station _{M a, M b, ··· M} n, and M'
_a , M ′ _b ,... M ′ _n , and (B) shows attenuated light for the purpose of compensating for attenuation of light intensity due to branching and propagation of light during transmission of an optical pulse from each station. FIG. 7C is an attenuation / amplification fluctuation waveform diagram of the light intensity obtained by optically amplifying the light intensity to the light intensity of the laser light emitted from the laser light source, and FIG. 9C shows the photoelectric conversion pulse trains P _a , P _b ,. _n and P '
_{a, P'b,} ··· _P'n and the propagation time width [Delta] T _ab between pulses, [Delta] T _bc, · · · [Delta] T _mn, and ΔT' _ab, ΔT'
FIG. 6 is a waveform diagram showing _bc ,... ΔT ′ _mn .

As shown in FIG. 1A, an optical transmission station 10a having a built-in pulse laser light source 4 which is turned on at predetermined time intervals in accordance with a command signal from a data processing device of a ground station is installed on the sea floor E. The pressure-resistant container 1 is made of iron, has a square pillar shape, a height of, for example, about 1.5 m, a weight of, for example, 200 to 300 kg, and the inside of the container 1 has a vacuum. It is maintained in a state or an atmospheric pressure, and has an optical system described later. Further, a refractometer 12 for detecting the refractive index of seawater, a temperature sensor 13 for detecting a water temperature using a thermistor, etc., and a water pressure sensor 1 using a strain gauge or the like are provided on the outer surface or the top surface of the pressure vessel 1.
4, for example, as a laser Doppler type flow velocity sensor 15 for flow velocity detection, a flow direction meter 16, and a salt concentration meter, for example,
A sodium ion electrode type or conductive salt concentration meter 17 is juxtaposed, and a seismometer 10 and an inclinometer 11 for detecting an inclination state of the light source light transmitting station 10a are provided inside the container 1, Is transmitted to a ground station (not shown) via a signal line 18 disposed in the container 1 and an external cable 103A described later.

As shown in FIG. 3, the outer cable 103A penetrating the lower part of the side wall of the pressure vessel 1 is, for example, an optical fiber cable for transmitting an optical signal from each station and a communication for transmitting observation data such as a photoelectric conversion pulse. Transmission cable 113 composed of a single line and a one-sided power supply line 123 surrounding the transmission cable 113
And the outer portion 133 surrounding the transmission cable 113 and the power supply line 123. The cable 103A interposed between the opposing pressure-resistant containers 1 is not affected even if the seabed between the opposing pressure-resistant containers 1 is distorted. The connection is made with a slack so that the container 1 does not fall down by absorbing the influence. In addition,
An iron wire may be wound around the exterior part 133 as necessary to increase the tensile strength. Of course, the armored cable 103B of the measuring line BB shown in FIG. 8 has the same configuration.

As can be seen from FIG. 1 (B), the 4
A window 3 made of Pyrex (registered trademark) or the like having pressure resistance and light transmissivity is provided on each side surface. Are provided with four eaves 2 projecting toward
However, it should not be contaminated by dead bodies such as plankton that settle on the sea floor.

Next, referring to FIG. 1A again, the optical system in the container 1 will be described. The laser pulse light emitted from the laser light source 4 is shown in FIG. In FIG. 5, the shape is schematically shown by a T-shape.
As shown in FIG. 4A, the optical power is incident on the port 51 of the preceding optical power branching coupler 5A to divide the optical power into two, and one of the branched pulse lights L1 is passed through the port 52 as shown in FIG. The lamp is turned on by the current supply from the power supply E1 through the switch SW closed by the incidence to transmit the light L2, and the lamp light L2 is transmitted to the photoconductor F of the optical amplifier. And a current is supplied from a power source E2 to an EL (electroluminescent element), and an optical pulse signal L3 obtained by amplifying the optical attenuation due to the above-mentioned branching to have the same light intensity as the light intensity emitted from the laser light source 4 is obtained. Emit.

Alternatively, as shown in FIG.
For example, erbium (E _r) Additive type optical fiber
Using a bar amplifier 6 ', the laser light is amplified and emitted.
You may. The configuration of the amplifier 6 'will be schematically described.
And Erbium (E_r) Is silicate glass, or
Optical fiber OF doped with phosphate glass
The input optical coupler IC and the filter
Ruta FIL, loop forming part of optical fiber OF, and its
An optical coupler C is connected to the output side, and further, the output side
And one of them has E_r980 nm, or 14
Pont with semiconductor laser coincident with 80 nm absorption line
The laser PL emits an optically amplified laser beam to the other side.
There is provided a light emitting part OT for power.

Then, the laser light of the pump laser PL is used.
Erbium (E) _rPhotoexcitation
And the dotted line input to the entrance IT of the optical fiber OF
The weak incident light having the wavelength of 1550 nm shown in FIG.
(Corresponding to the incident light L1 in (A)), and a solid line in the optical fiber OF.
The light is amplified while propagating as shown by
The output light of 1550 nm (shown by a solid line in FIG. 4 (A)
(Corresponding to the amplified optical pulse signal L3)
May be.

Then, the light is transmitted toward the subsequent branch coupler 5B shown in FIG. 5 (B). As shown in FIG. 5A, the other branched pulse light is incident on the photoelectric converter 9 through the port 53 whose end shown by the dotted line is bent slightly downward as shown in FIG. 1 (A)), which is converted into an electric pulse P.

Note that reference numerals D1 and D2 shown in FIG. 4A are transparent electrodes, and the glass adhered to the surface thereof is omitted. The branch coupler 5A shown in FIG. 5 is also used as a branch coupler for a relay station shown as a representative example in FIG. The branch coupler 5A is connected to the measurement line B
When used for the first transmitting station 20a of B, the transmitting station 10a
It is a matter of course that the end of the port 51 of the branch coupler 5A is configured to be slightly bent toward the light transmitting window of the transmitting station 10a so that the pulse light transmitted from the transmitting station 10a can be received.

To continue, as shown in FIG. 5 (B), one of the branched pulse lights which enters the port 51 of the subsequent optical power splitting coupler 5B and is split into the optical amplifier 6 via the port 52. Then, the other branched pulse light is transmitted as a propagation light pulse through the port 53, through the light transmission window 3 (not shown) provided on the side wall of the transmitting station 10a, and into the sea, and is transmitted to the adjacent one. The light is received via a light transmitting window 3 for receiving the branched light provided on the side wall of the head transmitting station 20a of the measurement line BB, and the laser light source 4
Amplifies the light so as to have the same light intensity as that of the laser beam from the light source and passes through the condenser lens 8 (see FIG. 2) and the light transmission window 3 to the next-stage relay station 20b. Light is sent.
On the other hand, a light absorbing member (or an optical isolator) 56 provided at the end of the port 54 absorbs the reflected light from the port 53.

In this way, the propagation pulse light is transmitted to the last relay station 10m (not shown), not shown, and from this relay station, as shown in FIG. One branch pulse light as an observation light pulse, which is incident on the port 51 of the branch coupler 5C provided in the receiving station 10n at the stage and is divided into the ports 52 and 53, is provided at the end of the port 52. The light is absorbed by the member 55, and the end portion is incident on the photoelectric converter 9 through the bent port 53, and is converted into an electric pulse P. Port 52
An optical amplifier 6 is provided at the end of the optical amplifier.

Note that the condensing lens 8 shown in FIG. 1 (A) is provided with an adjacent station when the container 1 lands on an inclined plane or when it lands on the sea floor with a level difference. A rotation for slightly rotating the lens 8 around the axis in the vertical direction of the pressure-resistant container 1 for the purpose of transmitting and receiving pulsed light without any trouble even if the light transmitting window and the light receiving window do not face each other accurately. Motion mechanism,
Angle of inclination with respect to the horizontal plane parallel to the transmission and reception directions, that is,
It is needless to say that a rotation mechanism for finely adjusting the inclination is provided to finely adjust the position of the lens 8 so as to enable reliable transmission and reception of light.

FIG. 2 shows the pressure-resistant container 1 of the relay stations 10b to 10m on the measurement line AA. Compared with the structure of the pressure-resistant container 1 of the transmitting station 10a, the difference is that the laser light source 4 and the branch coupler 5B are provided. And a condenser lens 8 is provided in front of the optical amplifier 6 before the branch coupler 5A.

The pressure-resistant container 1 of the last receiving station 10n.
When compared with the pressure-resistant container 1 of 10b to 10m for the relay station shown in FIG. 2, as shown in FIGS. 6 and 7, instead of the branch coupler 5A, the And that the lens 8 is not provided at the subsequent stage of the branch coupler 5C. Further, the branch couplers at the head transmitting station 20a, the relay stations 20b to 20m, and the receiving station 20n of the measurement line BB are configured similarly to the measurement line AA.

In FIG. 1 (A) and FIG. 2, reference numeral 20 indicates a stable holding for a long period of time without overturning the pressure-resistant container 1 under the influence of the pressing force of a low-rise water flow, sand drift, erosion and the like. For example, a leg member which is attached to the bottom surface of a weight 19 attached below the container 1 and has a sharp tip portion and is inserted into the seabed by the weight of the pressure-resistant container and water pressure. Is shown.

Now, as shown in the first installation example of FIG.
For example, a first set of survey lines A including stations 10a to 10n arranged at intervals of 30 m across the fault 60 of the seabed E.
A is arranged in parallel with the line AA.
The second is composed of the stations 20a to 20n arranged at 0 m intervals.
A set of measurement lines BB are arranged across the fault 61.

Next, the measurement line A shown in FIG. 6, FIG. 7, and FIG.
About the pulse generated and transmitted in A and the measurement line BB,
This will be described with reference to the waveform diagrams of FIGS.
As shown in FIG. 9 (A), and incident pulsed laser beam M _a laser light source 4 of the transmitting station 10a of survey line AA in branch coupler 5A, incident one branch pulsed light after the optical amplifier 6, FIG. As shown in FIG. 9 (B), a propagation pulse light, which is optically amplified so as to have the same light intensity as the light intensity of the laser light source 4 by the light attenuation due to the branching, is incident on the subsequent branch coupler 5B,
One of the branched pulse lights enters the optical amplifier 6 in the subsequent stage, and is further transmitted to the relay station 10b in the next stage through the light transmission window 3 of the pressure-resistant container 1. Light transmission window 3 of relay station 10b
The through, the optical pulse M _b which optically amplifies the same light intensity and the light intensity of the propagating light pulse of the laser light source 4 is incident on the branching coupler 5A of the relay station 10b by an optical amplifier 6, the light transmission window 3
Then, the light is transmitted to the next-stage repeater (not shown). In this manner, from the relay station 10m (not shown) to the final receiving station 10n
Is input to the optical amplifier 6 through the light transmission window 3, and after the optical amplification, the pulse light _Mn is branched and the pulse light is input to the branch coupler 5C.

Then, the branch coupler 5A of the transmitting station 10a
, The other branch pulse light M _a , the relay station 10b
Other branched light pulses M _b which is branched at the branch coupler 5A of the M _c · · ·, branch coupler 5C receiving station 10n of the final stage other branch pulsed light M _n as an observation light pulse respectively, each is incident on the photoelectric converter 9 ..., transmits electrical pulses P _a, P _b, the P _c ... P _n at the transmission cable 103.

In the measurement line BB, the transmitting station 1 of the measurement line AA
0a is branched by a branch coupler 5B (FIG. 5 (B)),
The branch pulse light transmitted into the sea through the light transmission window 3 is located at the head of the measurement line BB as shown in FIGS. 5A and 8 showing the branch coupler 5A as a propagation light pulse. The light enters the optical amplifier 6 in the pressure-resistant container 1 through the light transmission window 3 of the transmitting station 20a, and is optically amplified to the same light intensity as the laser light source. The pulse light transmitted from the optical amplifier 6 is branched by the branch coupler 5A, and one of the branched pulse lights is transmitted through the light transmission window 3 to the next-stage relay station 20b.
Light. Then, while transmitting light from the repeater 20b to the next-stage relay station (not shown), the light is transmitted to the final-stage receiving station 20n. Other branched light pulses _M'a branched by the branch coupler 5A of the relay station 20a, and the other branched light pulses M'
_b a · · · _M'n, respectively is incident on the photoelectric converter 9 as an observation optical pulses, the electrical pulses _{P'a, P'b} · · ·
The _P'n transmits to the ground station by transmission cable 103B.

[0043] The pulse P _a shown in FIG. 9 (C),
P _b, and _{··· P n, P'a, P'} b ··· P'n and the armored cable 103A, without transmitting to the ground station at 103B, the branch pulsed light as it is (or optical amplification After) A method of transmitting to the ground station is also possible. It is also possible to use a method in which a clock pulse is transmitted from a ground station to each station installed on the sea floor, the wavelength of the above-mentioned branched pulse light is counted, and this count value is transmitted to the ground station. Further, a set of branch pulses of the photoelectric conversion pulse train transmitted to the ground station, which is set between the stations installed opposite to each other, and the propagation time width ΔT of each set of the branch pulses is measured by a clock signal having a different frequency. Accurate measured values can be obtained by integrating the respective measured results.

Next, at the reference value measurement time t _{1 on the} measurement lines AA and BB and the measurement time t ₂ after a lapse of a predetermined time from the measurement of the reference value, the one-way optical pulse propagation time width between the opposed installation stations is measured. Data for obtaining ΔT, the propagation speed v of the light pulse, and the installation distance L between the opposing stations, and correcting the installation distance L of the opposing station that apparently fluctuates in response to the change in its parameter such as the refractive index n or the water temperature. A data processing device that performs processing and identifies whether or not a distortion amount has occurred between opposing stations will be described with reference to a functional block diagram shown in FIG.

FIG. 10 shows a printer connected to the CPU,
Has input / output devices such as a keyboard and mouse not shown
Data processing as described below.
Microcomputer that executes the control program of
Is a functional block diagram of a personal computer. Functionally explain this
First, in the measurement line AA, the detection unit
Depending on the installed sensor, measurement time t₁And t_TwoIn each
One measurement time, that is, N times for each short time of one second to several seconds
Refractive index of seawater, salt concentration, temperature and other parameters
And iterative detection, and as shown in FIG.
Then, each pressure vessel 1 on the seabed, that is, from each station to the ground station one after another
Photoelectric conversion pulse P transmitted to_a, P _b, P_c,
..P_nAnd then the counter section measures
Regular time t₁And t_TwoOne set of pulses P for each_aP_bAt the time of propagation between
Spacing ΔT_abAnd P_bP_cPropagation time width ΔT between_bcWhen,··
..P_mP_nPropagation time width ΔT between_mnCount and store in memory
Each propagation time width is stored.

The underwater light propagation velocity v at each station is given by the following equation (1) where v = C ₀ / n, where C ₀ is the light velocity in vacuum of 3 × 10 ⁸ (m / s). ) And n indicate the refractive index of water detected by a refractive index sensor installed at each station. Then, the relationship between the product of the propagation speed v and the propagation time ΔT of the underwater light pulse and the installation distance L between the opposing stations on the measurement line AA is expressed by an arithmetic expression (2) of v × ΔT = L. .

Therefore, when the value of the parameter g such as the refractive index n between the opposing stations, the salt concentration of seawater, the water temperature, the water pressure, the flow velocity, and the flow direction changes, the propagation speed v of the light pulse in the seawater changes. For this reason, for example, the installation distance L between the opposing stations between the i-th station and the (i + 1) -th station is affected by the fluctuation of the underwater propagation speed of the light pulse based on the fluctuation of the parameter g such as the refractive index. One-way propagation velocity v of the underwater light pulse between the i-th station and the (i + 1) -th station before correction: v _(j (i, i +
1)] and the measured propagation time width ΔT of the underwater light pulse from the i-th station to the (i + 1) -th station: [T _(j) (i, i +
1)], that is, (propagation velocity before correction [v _(j) (i, i + 1)]) × (measured propagation time width before correction [T _(j) (i, i + 1)]) = ( The distance between opposite stations before correction [L _(j) (i, i + 1)])... (2 ′), where i and (i + 1) are positive values and v _(j) , T _(j) indicate the values of the propagation speed and the propagation time width at the j-th measurement.

The ith of the right side of the above equation (2 ') and (i +
1) The opposing distance L between the stations does not depend on the occurrence or expansion and contraction of seafloor distortion, but rather fluctuates due to changes in the refractive index and parameters such as seawater temperature, salt concentration, flow velocity, and current direction. Is shown. Then, the i-th and (i
The true installation distance L between the (+1) th opposing stations, that is, the apparent inter-station distance after correcting the apparent fluctuation, is the above-mentioned distance [L _(j) ( i, i +
1)] and the correction amount δL of the i-th and (i + 1) -th opposing station installation distances, that is, (true inter-station installation distance L) = (inter-office installation distance L before correction) + (Correction amount). Specifically, (true installation distance between opposing stations [L _(j) (i, i + 1)]) = (installation distance between opposing stations before correction [L _(j) (i, i + 1)]) + (Correction amount [δL _(j) (i, i + 1)]) (2 ″) The numerical value of the distance L before correction of the first term on the right side of the equation (2 ″) is calculated by the above calculation. Although the value itself obtained by Expression (2) is shown, the calculation of the (correction amount) of the second term on the right side will be described below.

In general, it is not preferable to use only one measurement data as the correction amount because a more accurate result cannot be obtained. As already described, since the installation distance between the opposite stations is relatively short, for example, 30 m,
It is unlikely that the refractive index distribution and the parameter distributions such as the salt concentration during that period fluctuate greatly. Therefore, the i-th station and (i +
1) Among the stations, it is considered that the correction using either the average value <g> of the parameter detection values of the i-th station or the average value <g> of the parameter detection values of the (i + 1) -th station is sufficient. Can be

Therefore, the average correction amount calculating section of the data processing device, for example, for each measurement time t ₁ and t ₂ ,
The i-th and (i +
1) The detected values of each parameter g such as the refractive index, seawater temperature, salinity concentration, flow velocity, and flow direction, which are repeatedly detected N times by the sensors 12 to 17 installed in both stations, are calculated by the respective refractive index and salinity concentration. By dividing and adding each parameter, and dividing each addition value by the number of detections N, the i-th station,
Alternatively, the short-term average value of each parameter g such as the refractive index at the (i + 1) -th station, in other words, the short-time average correction amount <g
> Ask for.

By the way, the correction amount [δL _(j) (i, i + 1)] shown in the second term on the right side of equation (2 ″), that is, <δL>
Is a function of variation (δg) of each parameter g such as a refractive index, a salt concentration, and a water temperature in a propagation path of a laser pulse light;
Since they are expressed as the sum of artificial fluctuations caused by noise of measuring equipment, these are combined and the short-term average correction amount <δL> =
F (parameter) + <δL (measurement device)>. In the following, for the sake of simplicity, <δL (measurement device)> is assumed to be zero, but of course, <δL (measurement device)> may be estimated by a test of a measurement device separately performed. And
When the above F (parameter) is linearly approximated as <δL (parameter)> and expressed as the sum of linear linear approximation formulas for each parameter, <δL (parameter)> = <δL (influence of variation only in refractive index)> + <ΔL (influence of fluctuation only in salt concentration)> + <δL (influence of fluctuation only in water temperature) ++ <δL
(Influence of fluctuation only in water pressure)> + <δL (Effect of fluctuation only in flow velocity)> + <δL (Effect of fluctuation only in flow direction) ++.
・ It can be described as

Actually, for example, any one of the parameters g such as the refractive index is selected, and the short-time average correction amount <g> calculated by the average correction amount calculation unit is set to <
δL (parameter)>, and this <δL (parameter)> is the true short-time average correction amount <δL for the correction calculation of the distance L between each station shown in the second term of the above equation (2 ″). >
It was decided to use it as equivalent to. <ΔL (parameter)>, which is the short-time average correction amount, is as follows: <δL (parameter)> = (Σ _(j) ^N [δL (parameter) _(j) (i, i + 1)]) / N · ··· (3 ′) The measurement accuracy is improved by √N times by obtaining the average value of the N repeated detection values as described above. Thus, the true distance L obtained by adding the installation distance L between the opposite stations before the correction and the short-time average correction amount <δL (parameter)> is stored in the memory.

Next, in the measurement line AA, the parameter g
To select only the refractive index n of one of the stations,
Calculation of true installation distance L between station and (i + 1) th station
And the measurement time t₁To t_TwoCalculate the amount of distortion that occurred during
Will be described. As shown in FIG.
If the tomographic observation start time t₁That is, one second to several seconds
Short time t₁During the i-th station or (i + 1) -th station
N repetitions of the refractive index n of water by the installed refractometer 12
Detection is performed and the observation start time (when measuring the reference value) t₁From
Time t after elapse of predetermined time_TwoAs well as a short time of one second to several seconds
t_TwoWhile performing N repetitive detections of the refractive index n during
The i-th and (i) calculated by the above arithmetic expressions (1) and (2)
+1) the distance L between the stations before correction and the data
I-th, calculated by the average correction amount calculation unit of the processing device
Or the short-time average of the refractive index n detected at the (i + 1) -th station.
Average correction amount <δL (parameter)>_t1And t = t
₁Between the i-th and (i + 1) -th stations after correction in
Distance L of_t1 ^CWhen expressed as (i, i + 1), the distance calculation unit
Then, L_t1 ^C(I, i + 1) = (measurement time t₁Complement in
Installation distance [L_{(j )}(I, i + 1)]) +
(At the time of measurement₁Short-term average correction amount <δL (parameter
Data)>_t1)... (4), and similarly, t = t
_TwoAfter correction between the i-th and (i + 1) -th opposing stations in
Is the true distance L of_t2 ^CDenoting (i, i + 1), L_t2
^C(I, i + 1) = (measurement time t_TwoOpposition before correction in
Installation distance between stations [L _(j)(I, i + 1)]) + (at the time of measurement
t_TwoShort-term average correction amount <δL (parameter)>
_t2) (4 ′)

Further, at the time of measurement t _{1 to} t ₂ and the change in strain ε
FIG. 11 showing the relationship with the fluctuation tendency of
The fluctuation amount of the true installation distance L between the i-th and (i + 1) -th opposing stations during the measurement time t _{1 to} t ₂ , in other words, the distortion change amount ε is represented by the following equation: [ε (i, i + 1)] _t1 ^t2 ≡
{(True opposite station between the installation distance corrected in the measurement time t _{2 ^{[L t2 C (i, i +}} 1) ] - (opposite station between the installation distance before correction in the measurement time t _{1 ^{[L t1 C (i, i +}} 1 )])｝ ／
0.5 × ｛(true inter-station distance after correction at measurement time t ₁ [L _t1 ^C (i, i + 1)]) + (true inter-station distance after correction at measurement time t ₂ [ L _t2 ^C (i, i
+1)])｝ (5A) or the following arithmetic expression:
[Ε (i, i + 1)] _t1 ^t2 ≡ {(true between the opposing station installation distance after correction in the measurement time t _{2 ^{[L t2 C (i, i +}} 1) ]
− (Setting distance between opposing stations before correction at measurement time t ₁ [L
^{_{t1 C (i, i + 1}} ) ])} / (the true opposite station between the installation distance corrected in the measurement time t _{1 ^{[L t1 C (i, i +}} 1) ])
(5B)

[0055] In comparison unit, the difference measurement capability (measured at the calculated value of the true distance L _t2 after the correction in t ₂₎ and (calculated value of the true distance L _t1 corrected in the measurement time t ₁₎ If the difference is equal to or less than the limit (for example, 10 ⁻⁸ ) and equal, no significant distortion occurs between the reference value measurement time t ₁ and the measurement time t ₂ after a lapse of a predetermined time. It is determined that a distortion has occurred, and a signal indicating the amount of distortion change obtained by the above-described arithmetic expression (5A) or (5B) is output.

The same applies to the measurement line BB.
Using only the refractive index n of one of the stations as data g
Of the true installation distance L between the i-th station and the (i + 1) -th station
Calculation and measurement time t₁To t_TwoCalculation of the amount of distortion that occurred during
Will be explained. As shown in Fig. 11, seafloor fault observation
Start time t₁I-th station or (i + 1) -th station
Of the refractive index n of water N times
Re-detection is performed, and the observation start time (when measuring the reference value) t₁Or
Time after a predetermined time elapses_TwoN times anti-refractive index
Detection, and the above equations (1) and (2) are used.
Between the i-th and (i + 1) -th stations calculated
The distance L in front and the average correction amount calculation unit of the data processing device
Detected at i-th or (i + 1) -th station
Short-term average correction amount of refractive index n <δL (parameter)
>_t1And the distance calculation unit uses the corrected i-th and (i +
1) Let the true distance L between the stations be L_t1 ^C(I, i + 1)
= (At measurement t₁In the opposite station before correction [L
_{(j )}(I, i + 1)]) + (measurement t₁Short time in
Average correction amount <δL (parameter)>_t1) ... (4)
T = t_TwoAnd the (i +
1) The corrected true distance L between the opposing stations is L
_t2 ^C(I, i + 1) = (measurement time t_TwoBefore correction in
Installation distance between stations [L _(j)(I, i + 1)]) + (measurement
Time t_TwoShort-term average correction amount <δL (parameter)
>_t2) (4 ′)

Further, the fluctuation amount of the true installation distance L between the i-th and (i + 1) -th opposing stations during the measurement time t _{1 to} t ₂ , that is, the distortion change amount ε is calculated by the following equation (5A), [ε
(I, i + 1)] _t1 ^t2 ≡ {(true opposite station between the installation distance corrected in the measurement time t ₂ [L _t2 ^C (i, i + 1)] -
(Opposite station between the installation distance before correction in the measurement time t ₁ [L _t1
^C (i, i + 1)])｝ / 0.5 × ｛(True installation distance after correction at measurement time t ₁ [L _t1 ^C (i, i +
1)]) + (True installation distance between corrected opposing stations [L _t2 ^C (i, i + 1)])｝ after correction at measurement time t ₂ , or the following equation (5B), [ε (i, i + 1)] ] _t1 ^t2 ≡ {(true opposite station between the installation distance corrected in the measurement time t ₂ [L _t2
^C (i, i + 1)] - (opposite station between the installation distance before correction in the measurement time t _{1 ^{[L t1 C (i, i +}} 1) ])} / (true inter opposite station after correction in the measurement time t ₁ installed Distance [L _t1 ^C
(I, i + 1)]).

[0058] In comparison unit, the difference measurement capability (measured at the calculated value of the true distance L _t2 after the correction in t ₂₎ and (calculated value of the true distance L _t1 corrected in the measurement time t ₁₎ If the difference is equal to or less than the limit (for example, 10 ⁻⁸ ) and equal, no significant distortion occurs between the reference value measurement time t ₁ and the measurement time t ₂ after a lapse of a predetermined time. It is determined that a distortion has occurred, and a signal indicating the amount of distortion change obtained by the above-described arithmetic expression (5A) or (5B) is output.

Next, it was arranged over the faults 60 and 61.
The operation of the measurement lines AA and BB will be described below. Now, FIG.
It is generated from the laser light source 4 of the optical transmitting station 10a shown in FIG.
The split optical pulse is split by the splitter coupler 5A at the previous stage,
The amount of attenuation due to the branch is reflected by the optical amplifier 6 from the laser light source 4.
Light pulse M amplified to the same intensity as the light intensity of the light pulse
_a(FIG. 9A) is incident on the subsequent branch coupler 5B,
Further, the amount of attenuation due to the branch is calculated by the optical pulse from the laser light source 4.
(FIG. 9 (B)), and passes through the light transmission window 3.
Then, the light is transmitted toward the light transmission window 3 of the relay station 10b at the next stage.
You. The other branch branched by the branch coupler 5A
A pulse P obtained by photoelectrically converting the pulse light by the photoelectric converter 9 _a
To the ground station (not shown) via the transmission cable 103A.
(FIG. 9C).

The light pulse received through the light transmission window 3 of the repeater 10b at the next stage is amplified by the optical amplifier 6 to the same intensity as the light intensity of the light pulse from the laser light source 4, and is branched by the branch coupler 5B. Is input to the optical amplifier 6 and further transmitted through the light transmission window 3 to the next-stage relay station. In this way, the branched pulse light is successively transmitted to the subsequent relay station. I do. The other branch pulse light M _b branched by the branch coupler 5A of the relay stations 10b,.
M _c, ··· M _m electricity by photoelectric converter 9 pulses P _b, P _c, converted into · · · P _m, the transmission cable 103
To a ground station (not shown). In the receiving station 10n at the last stage, one of the branched pulse lights incident through the light transmission window 3 is amplified by the optical amplifier 6 to the same intensity as the light intensity of the optical pulse from the laser light source 4, and branched by the branch coupler 5C. photoelectric conversion pulse P _n of the other branched light pulses M _n was
Is transmitted via the transmission cable 103 in the same manner.

On the other hand, as shown in FIGS.
The branched pulse light branched by the 0a branch coupler 5B is incident on the optical amplifier 6 at the preceding stage via the light transmission window 3 of the transmitting station 20a at the head of the adjacent measurement line BB, and has the same intensity as the light intensity of the laser light source 4. One of the optically amplified branched pulse lights M '
_a is input to the branch coupler 5A, one of the branched pulse lights is input to the optical amplifier 6 at the subsequent stage, and is amplified to the same intensity as the optical intensity of the laser light source 4; 2
0b. Then, it sent into an electric pulse _P'a the other branch pulsed light branching coupler 5A by the photoelectric converter 9. Thus, one of the branched optical pulses is successively transmitted to the final receiving station 20n via the subsequent relay station 20b. On the other hand, the relay station 20b,
· Branch coupler 5A other split pulsed light _M'b which is branched at, M _c ', ··· _M'n electrical pulses by a photoelectric converter 9 _{P'b, P'c,} ··· P Convert to _´n
The signal is transmitted to a ground station (not shown) via the transmission cable 103.

Referring to the flowchart shown in FIG.
The processing of the detection data transmitted from the station will be described.
You. In the detection unit of the data processing device of the ground station, FIG.
As shown in the figure, the transmitting station 10a of the survey line AA, the relay station 10
b,..., light sequentially transmitted from the receiving station 10n
Electric conversion pulse P_a, P_b, P_c, ... P_nAnd survey line B
B relay stations 20a,...
The transmitted photoelectric conversion pulse P '_a, P '_b, P '_c,
... P '_nAlong with the path from survey line AA.
Luth P_aP_bPropagation time width ΔT between_ab, Pulse P_bP_cwhile
Propagation time width ΔT _bc, ..., Pulse P_mP_nBiography
Seeding time width ΔT_mnAnd the pulse P 'from the measurement line BB_aP '_b
Propagation time width ΔT 'between_ab, Pulse P '_bP '_cPropagation between
Time width ΔT '_bc, ..., pulse P '_mP '_nBiography
Seeding time width ΔT '_mnAre counted by the counter section, and at the time of measurement t
₁, T_TwoStore each propagation time ΔT in the memory
(Step S1). Then, each of the measurement lines AA and BB
Refractive index of station location, water temperature, water pressure, flow direction, flow velocity, salt concentration
The degree parameter g is set to the i-th or (i + 1) -th pair.
A refractometer 12, a temperature sensor 13, and a hydraulic pressure
Sensor 14, flow rate sensor 15, flow direction meter 16, salt concentration meter 1
T = t at the time of measurement by the sensor 7₁And from this time
Measurement time after elapse of fixed time t = t_TwoIn, for example, 1 second
N times detection within a short time of ~ several seconds (step
Step S2). And the speed of light in vacuum stored in the memory
Degree C₀And the refractive index n into the arithmetic expression (1),
The propagation speed v is obtained, and the propagation speed v and the i-th and (i +
1) Substitute the propagation time ΔT between the stations into the arithmetic expression (2)
To calculate the distance L before correction (step 3).

Next, in the average correction amount calculating section, step S
Refractive index, water temperature, salt on the measurement lines AA and BB detected in 2
Short-term average correction amount by each parameter g such as partial concentration (Σ
_(j) ^N[Δg_(j)(I, i + 1)]) / N
Out, that is, <δL (parameter)> is obtained (step
S4). In the distance calculation unit, the bending calculated in step S4 is performed.
Of the short-time average correction amounts <g> such as the folding index n, the refractive index n
The short-term average correction amount <g>, in other words, <δL (P
Calculation of the true installation distance L between the opposing stations using
Go out.

That is, the fluctuation amount of the true inter-installation distance L between the opposing stations of the measurement lines AA and BB, for example, between the i-th station and the (i + 1) -th station, that is, the distortion amount ε, The calculated true distances L _t1 ^C and L _t2 ^C after correction at ₁ and t ₂ are calculated by the following equation: [ε (i, i + 1)] _t1 ^t2 ≡ ｛(true opposition after correction at measurement time t ₂ ) between stations installation distance ^{_{[L t2 C (i, i +}} 1) ] - (between opposing station installation distance before correction in the measurement time t _{1 ^{[L t1 C (i, i +}} 1) ])} / 0.5 × {(measured Corrected installation distance between opposing stations at time t ₁ [L _t1 ^C (i, i + 1)] + (corrected installation distance between opposing stations at measurement time t ₂ [L _t2 ^C (i, i + 1) )])} · · · (5A), or, [ε (i, i + 1)] _t1 ^t2 ≡ {(opposite station between the installation distance corrected in the measurement time t _{2 ^{[L t2 C (i, i +}} 1) ]) (Measurement time t ₁ opposite station between the installation distance ^{_{[L t1 C (i, i +}} 1) ] after correction in)} / (measured at the true opposite station between Installation distance after correction in t ₁ [L _t1 ^C (i , I + 1)]) (5B) (step S5).

In the comparison section, the difference between (the calculated value of the corrected true distance L _t2 at the measurement time t ₂ ) and (the calculated value of the corrected true distance L _t1 at the measurement time t ₁ ) is the measurement capability. limit (e.g., 10 ^-8) if below (step S6), and does not generate significant strain during the measurement time t ₁ ~t ₂ if the two values are equal (step S8), and significant otherwise strain Is generated (step S7), and the identification signal and a signal indicating the estimated value of the distortion are output.

Thus, the discrimination signal is sent to the refractometer 12, the temperature sensor 13, the water pressure sensor 14, the flow direction meter 15, and the current meter 1.
6. Water temperature, water pressure, flow direction measured by the salinity meter 17,
The data is sent to the printer and the CRT together with the measurement data of the parameters such as the flow velocity and the salt concentration (step S9). AA,
The presence / absence of distortion between all opposing stations in the BB is identified, and the amount of distortion is calculated. At the time of measurement t
It is a matter of course that the presence or absence of distortion and the amount of distortion are detected from each measurement value at the measurement time t ₃ ... T _n after the lapse of ₂ and each measurement time t ₁ .

In the above-described example, the shape of the side portion of the storage container of the optical distance measuring device is specified as a quadrangular prism, and light transmitting windows are provided on the four side surfaces. Only the side wall at the height position is formed in a cylindrical shape, or the entire side wall is formed in a cylindrical shape, and light transmitting and receiving directions are provided in three directions by providing light transmitting windows at 120 °, 90 °, 60 ° or 45 ° intervals. , 4
It is also possible to arbitrarily branch the directions, six directions, and eight directions to enable transmission and reception, or to provide a light transmission window at every 90 ° and to configure three directions as transmission and reception directions. Further, when light is branched and transmitted in multiple directions, the branch coupler shown in FIG. 5 is branched in two directions. For example, in order to branch received light in three directions, the branch coupler is interposed with an optical amplifier. It suffices that two couplers are provided vertically. Therefore, the number of branch couplers corresponding to the increase in the number of branch directions may be arranged in the branching station.

Further, since the inclinometer 10 is provided in the casing, when the optical distance measuring device of the present invention is laid in an inclined state, the inclination signal of the inclinometer is transmitted to the ground station and identified. Then, the operator who pulls the cable (not shown) provided in each relay station using, for example, a cable laying work boat, can correct and install the inclination of each relay station. Further, in the above embodiment, a data processing device is provided in any one of the transmitting station, the relay station, and the receiving station, and performs processing of the detection data to obtain discrimination data, and then transfers the data to the ground station. Of course, it is good.

Next, the already described <δL (parameter)>
Is not limited to the short-time average correction amount of any one parameter g in any one of the opposing stations, but may be any of a plurality of arbitrary parameters g obtained in any one of the opposing stations. When the short-time average correction amount <g> is added,
Alternatively, the short-term average correction amount <g> of an arbitrary plurality of parameters g obtained in each of the opposing stations is added and the number of opposing stations is 2
This is also applied to the case where the average value is divided by the following expression. In these cases, the short-time average correction amount is set to <δL for discrimination.
'(Parameter)>. By the way, when adding the short-time average correction amount <g> of the plurality of parameters g obtained in any one of the opposite stations, the arithmetic expression (3
According to A), <δL ′ (parameter)> = <δL (effect of variation only in refractive index)> + <δL (effect of variation only in salt concentration) ++ <δL (effect of variation only in water temperature) + <Δ
L (influence of fluctuation only in water pressure)> + <δL (influence of fluctuation in only flow velocity)> + <δL (influence of fluctuation in only flow direction)> When the short-term average correction amount <g> of the parameter g is added and the number of opposing stations is 2, in other words, when the average value obtained by dividing by 0.5 is represented by the arithmetic value (3B), <δL ′ (parameter)>
= 0.5 × ｛([<δL (influence of variation only in refractive index)) ++ δL (influence of variation only in salt concentration) ++ <δL (influence of variation only in water temperature)> + <ΔL
(Influence of fluctuation only in water pressure)> + <δL (Effect of fluctuation only in flow velocity)> + <δL (Effect of fluctuation only in flow direction)>)) +
([<ΔL (influence of variation only in refractive index)) ++ δL (influence of variation only in salinity)> + <δ in the other station
L (Influence of fluctuation only in water temperature)> + <δL (Effect of fluctuation only in water pressure)> + <δL (Influence of fluctuation only in flow velocity)> + <
δL (influence of fluctuation only in flow direction)>])｝.

Next, a value obtained by adding the short-time average correction amounts <g> of arbitrary parameters g obtained by any one of the opposing stations, or “arbitrary parameters obtained by each opposing station” The average value obtained by adding the short-time average correction amounts <g> of the plurality of parameters g and dividing by the number of opposing stations 2 ”is expressed as <δL ′ (parameter)>, and the distortion amount using The calculation will be described. In this case, the process before calculation of each short-time average correction amount <δL (parameter)> when any one parameter g of any one of the opposite stations is selected is the same. Since the subsequent processing steps are slightly different, the differences will be described below.

First, <δL ′ (parameter)> is the sum of the respective short-time average correction amounts using a plurality of arbitrary parameters g detected at the measurement times t ₁ and t ₂ , and any one of the opposite stations is used. When any of a plurality of parameters g obtained at the station, for example, the parameters g of the refractive index and the salt concentration, are selected, <δL ′ (parameter)> is obtained by the arithmetic expression (3A).
= <ΔL (influence of variation only in refractive index)> + <δL (influence of variation only in salt concentration)> to calculate the true installation distance L between the opposite stations after correction, (4B)
To the second term on the right side of. Further, each short-time average correction amount <g> using an arbitrary plurality of parameters g obtained in each station of the opposite station, for example, the refractive index in each station,
When the parameter g of the salt concentration and the water temperature is selected, <δL ′ (parameter)> = 0.5 by the arithmetic expression (3B).
× ｛([<δL (influence of variation only in refractive index)) in one station> + <δL (influence of variation only in salt concentration)> + <
δL (effect of fluctuation only in water temperature)>) + ([<δL (effect of fluctuation only in refractive index)) ++ δL in the other station
(Influence of variation only in salt concentration)> + <δL (Influence of variation only in water temperature)>))｝ is calculated, and in this case, similarly, the following calculation for calculating the true corrected installation distance L between opposing stations is similarly performed. Equation (4
A) and (4B) are substituted for the second term on the right side.

In any case, the true installation distance L between the opposing stations after the correction at the measurement time t ₁ is L = [L _t1 ^C (i, i + 1)] = (the value before the correction at the measurement time t ₁ ) Distance between opposing stations [L _(j) (i, i + 1); t = t ₁ ]) + (short-time average correction amount at measurement time t ₁ <δL '(parameter)> _{t 1} ) as shown in (4A), the correction in the measurement time t ₁ from the sum of the measured time between the opposed stations before correction in t ₁ installation distance L _(j) and the short-term average correction amount <δL'(parameter)> _t1 true with obtaining the opposite station between the installation distance L after, installation distance L between the true opposite station after correction in the measurement time t ₂ is between true opposite station installation after correction in the measurement time t ₂ distance L = [L _t2 ^C (i, i + 1)] = (Distance between opposite stations before correction at measurement time t ₂ [L _(j) (i, i + 1); t = t ₂ ) ]) + (Measured at the short-term average correction amount in t ₂ <δL'(parameters)> As shown in _t2) · · · arithmetic expression (4B), between the opposing station installation distance before correction in the measurement time t ₂ L _(j) and the short-term average correction amount <δL'(parameter)> obtaining a true between the opposing station installation distance L after correction in the measurement time t ₂ from the sum of _t2.

Next, Δ (at the time of measurement t_TwoOf the true installation distance between opposing stations [L_t2 ^C(I, i + 1)])-(measurement t₁Of the true installation distance between opposing stations [L_t1 ^C(I, i + 1)])｝ / 0.5 × ｛(t at the time of measurement₁The corrected installation distance between opposing stations [L_t1 ^C(I, i + 1)]) + (measurement t_TwoCorrected distance between opposing stations [L_t2 ^C(I, i + 1)])｝ ... Equation (5A) or ｛(measurement t_TwoOf the true installation distance between opposing stations [L_t2 ^C(I, i + 1)])-(measurement time t₁Of the true installation distance between opposing stations [L_t1 ^C(I, i + 1)))｝ / (measurement t₁Of the true installation distance between opposing stations [L_t1 ^C(I, i + 1)])... Of the numerator of the arithmetic expression (5B)_TwoBetween true opposing stations after correction at
Installation distance L_t2), (At the time of measurement t₁After correction in
True distance L between stations_t1) Based on the result of the difference
To identify whether or not distortion has occurred between opposing stations, and
Then, based on the arithmetic expression (5A),_TwoIn
True corrected installation distance L between opposing stations_t2And the time of measurement t
₁Corrected inter-station distance L after correction in_t1Of the value of
Difference) and the above (t₁And t_TwoTrue after correction in
Installation distance L between opposing stations_t1And L_t2Average value of｝)
From the opposite station [ε (i, i + 1)]_t1 ^t2
Or ｛(measurement time t)_TwoTo
Corrected distance L between opposing stations after correction_t2Value and measurement
Regular time t ₁Corrected inter-station distance L after correction in_t1of
Value) and the above (at the time of measurement t)₁True pair after correction in
Installation distance L between stations_t1Occurs between opposing stations based on the ratio of｝)
Distortion [ε (i, i + 1)]_t1 ^t2Can ask for
You.

Next, a description will be given of an embodiment in which a large number of measurement lines for executing the above-described measurement processing are branched and arranged in several directions across several slices. FIG. 13 is a block diagram of a second installation example in which a large number of survey lines are branched and arranged in multiple directions across several faults in order to further expand the observation area. Transmitting station 10A, relay station 1
.. 10F,... 10M and the receiving station 10N are laid in a straight line across the toms 71 and 72, and the optical pulse transmitted from the transmitting station 10A is
OB,... 10M, and propagates to the receiving station 10N one after another.

The relay station 10F of the measurement line AA is an optical pulse branching station, and an optical pulse is transmitted through two light transmission windows (not shown) to one of the measurement lines BB arranged in the orthogonal direction.
Is transmitted to the light transmitting window of the first transmitting station 30A, and further transmitted to the final receiving station 30N via a relay station (not shown), while being transmitted to the light transmitting window of the first transmitting station 40A of the other measurement line CC. The light is transmitted to a final-stage receiving station 40N via a relay station (not shown).

Also, the relay station 10M is an optical pulse branching station, and the optical pulse is transmitted through the two light transmission windows (not shown) to the optical transmitter of the head transmitting station 50A of one of the measurement lines HH arranged in the orthogonal direction. While transmitting the light to the transmission window and transmitting the light to the final receiving station 50N via the relay station (not shown), the light is transmitted to the light transmission window of the head transmitting station 60A of the other measurement line JJ, and the relay station (not shown) is transmitted. The light is transmitted to the receiving station 60N at the final stage via the optical path.

Further, the receiving station 10N of the measurement line AA is an optical pulse branching station, and the optical pulses are arranged at an angle of about 90 ° with each other through the light transmitting window and straddling the tomographic cross section 73. To the head transmitting station 70A of one of the measurement lines KK, and the final receiving station 70N via a relay station (not shown).
And the head transmitting station 80A of the other measurement line LL
And the light is transmitted to the final receiving station 80N via a relay station (not shown).

Then, the measurement lines AA, BB, HH, JJ, K
The photoelectric conversion pulse P generated from each station of K and LL and the measured refractive index, water temperature, water pressure, flow direction, flow velocity, and salt concentration data of seawater are converted into parallel transmission cables 103A, 103B,
Via 103C, 103H, 103J, 103K, 103L, it is transported via a transmission cable 103T accommodating these transport cables, and the ground station executes the data processing already described. As mentioned above, the observation area is 7
Since it is laid by the measurement lines, it is possible to expand the observation area.

Next, referring to FIG. 14, which shows a block diagram of a third installation example in which a large number of survey lines are laid in parallel on the sea floor, for example, a transmitting station 10a which generates optical pulses arranged at intervals of 30 m, The relay station 10b ..., the measuring line AA in which the receiving station 10n is laid in a straight line, the head transmitting station 20a to which the branch optical pulse from the transmitting station 10a is transmitted, the relay station 20b, ...
A measuring line BB in which the receiving stations 20n are laid in a straight line, and a head transmitting station 30a, a relay station 30b,..., The receiving station 30 to which the branch optical pulse from the head transmitting station 20a of the measuring line BB is transmitted.
n The line CC laid in a straight line, and the head transmitting station 4 to which the branch optical pulse from the head transmitting station 30b of the line CC is transmitted.
0a, a relay station 40b,..., A measuring line DD in which receiving stations 40n are laid in a straight line, and one of the first transmitting station 50a, the relay station 50b, to which a branch optical pulse is transmitted from the first transmitting station 40a of the measuring line DD. .. and a measuring line EE in which the receiving stations 50n are laid in a straight line are arranged in parallel on the sea floor. And line A
A, the photoelectric conversion pulse P generated from each station on the measurement line BB, the measurement line CC, the measurement line DD, and the measurement line EE, and the measurement data of the seawater temperature, water pressure, flow direction, flow velocity, and salinity concentration at the laying position were respectively arranged in parallel. Transport cable 103
Transported to ground stations via A, 103B, 103C, 103D, and 103E. Also in this case, the same data processing as the data processing such as the temperature compensation due to the seawater temperature fluctuation described above is performed.

FIG. 15 shows a fourth example in which an observation station is laid so as to form a two-dimensional spread at each vertex forming position of a large number of triangles on the sea floor, similarly to the triangulation network installed on the ground by the Geographical Survey Institute. It is a block diagram of an example of an installation. In this embodiment, the propagation time between two adjacent stations is measured.
Identifying the presence or absence of difference between the measured value of the time t ₁ from the measurement time t ₁ and the measurement value of the predetermined time elapsed measured time t _2, thereby, the presence of expansion and contraction of the crust interposed between two stations Although this embodiment is different from the above-described embodiments in the point of discrimination, the subsequent data processing such as temperature correction is the same as that described above.

In FIG. 15, for example, every 30 m, the observation stations 10A1.
6B, 10B1, 10B7, 10C1, 10C7, 10D2,
10D7... Are laid, for example, at each vertex forming position of an equilateral triangle.

Next, with reference to FIG. 16 showing a trapezoidal region S of the observation network extracted from FIG. 15, the configuration of the observation station used in this observation network, the propagation of the optical pulse between the observation stations, and the propagation time T Will be described. Although all of these observation stations have the same configuration, the observation station 10B3, which is the center of the explanation of the measurement of the propagation time, will be described with reference numerals for the related members, and the adjacent observation stations will be described with respect to the members related to the above description. Only the reference numerals will be described, and the description will not be duplicated.

The horizontal line position on the left side of the horizontal axis in the observing station 10B3 is set to 0 °, and 6 degrees clockwise from here.
Three photoelectric converters 9A, 9 at an angular interval of 0 °
B, 9C, and the horizontal line position on the right
The laser light sources 4C, 4C, which generate pulsed light, are spaced at an angular interval of 60 ° clockwise from here.
B, 4A. The laser light sources 4A, 4B, and 4C are connected to a power supply cable in a transport cable (not shown), and are configured to be simultaneously turned on at predetermined time intervals according to a command from a data processing device of a ground station. . According to the configuration of the observation station, it is not necessary to provide the branch couplers 5A to 5C and the optical amplifier 6 unlike the observation station described so far, and the configuration can be simplified.

Next, as an example, the propagation of the optical pulse to the adjacent station centering on the observation station 10B3 and the propagation times T ₁ , T ₁ between this station 10B3 and the adjacent stations 10A2 and 10A3.
₂ , the propagation time T between adjacent stations 10B2 and 10B4
₃ , T ₄ and the measurement of the propagation times T ₅ and T ₆ between the adjacent stations 10C3 and 10C4 will be described.

The light transmitting pulse from the adjacent station 10A1 (see FIGS. 15 and 16) is received by the photoelectric converter 9A of the station 10A2.
The generated photoelectric conversion pulse K1 is transmitted to the transmission cable 104A1.
To the counter section in the data processing device of the ground station. Then, the optical pulse of the laser light source 4A which is turned on at the same time is transmitted to the photoelectric converter 9C of the adjacent station 10B2, the optical pulse of the laser light source 4B is transmitted to the photoelectric converter 9B of the adjacent station 10B3, and the generated pulse K2 is transmitted. The data is transmitted to the counter section via the cable 104B5, and the opposite stations 10A2 and 10B are transmitted.
3 to output the count value of an optical pulse propagation time T ₁ of the between, also the optical pulse of the laser light source 4C neighbor 10A3
To the photoelectric converter 9A, and transmits the generated pulse K3 to the counter unit via the cable 104A4.

The optical pulse from the laser light source 4A of the station 10A3 is transmitted to the photoelectric converter 9C of the adjacent station 10B3.
6, the pulse K3 is transmitted to the counter unit to which the pulse is transmitted. Therefore, count value indicating the propagation time T ₂ of the optical pulse between the counter station 10A3 and 10B3 is output.

The optical pulse from the adjacent station 10B1 (FIG. 15,
16) is received by the photoelectric converter 9A of the station 10B2, and the generated pulse K5 is transmitted to the counter unit via the cable 104B1. On the other hand, the photoelectric converter 9A of the adjacent station 10B3 receives the optical pulse from the laser light source 4C of the station 10B2 via the cable 104B4 in this counter section.
Since the generated pulses K6 is transmitted, the count value of the optical pulse propagation time T ₃ between this from the counter and the counter station 10B2 10B3 is output.

The laser light sources 4A to 4C of the station 10B3 are simultaneously turned on, the optical pulse of the laser light source 4A is transmitted to the photoelectric converter 9C of the adjacent station 10C3, and the generated pulse K8 is transmitted via the cable 104C6 and transmitted. is input to the counter unit is, the count value of the propagation time T ₅ of the optical pulse between the counter station 10B3 and 10C3 is output.

The optical pulse from the laser light source 4B of the station 10B3 is received by the photoelectric converter 9B of the adjacent station 10C4.
The generated pulse K9 is transmitted to the station 10B via the cable 104C8.
3 is input to the counter unit to which the generated pulse K6 is transmitted via the cable 104B4, and the opposite stations 10B3 and 10B3
Count of propagation time T ₆ of the optical pulse between C4 is output.

Further, from the laser light source 4C of the station 10B3
Is transmitted to the photoelectric converter 9A of the adjacent station 10B4.
The generated pulse K7 is transmitted to the station 1 via the cable 104B7.
Generated pulse K6 from 0B3 via cable 104B4
Is transmitted to the counter unit
Optical pulse propagation time T between the stations 10B3 and 10B4 _Four
Is output. In the ground station data processing equipment
Is the above propagation time T₁~ Propagation time T₆Detect
However, for other data processing such as temperature correction,
Perform as described. In addition, the above observation stations are equilateral triangles.
Has been explained at the vertex position of
And other triangles with arbitrary angles
Noh. In that case, three photoelectric converters and three lasers
The laser light source is designed to perform the functions described in the above embodiments.
The example of arranging at an arbitrary angle was described.
It is also possible to arrange over the.

The embodiments shown in FIGS. 13 to 15 also have a short-time average correction amount <δL (parameter)>,
It goes without saying that the above-described measurement processing for obtaining the true installation distance L between stations on the measurement line using <δL ′ (parameter)> can be applied.

Next, referring to FIG. 17, the change in the propagation speed v of the light pulse due to the change in the water temperature will be described with reference to FIGS.
An example of the optical distance measuring apparatus according to the second embodiment of the present invention, which can perform temperature compensation more precisely than the optical distance measuring apparatus shown in FIG.

As shown in FIG.
For example, a transmission cable 103A extending from a ground station (not shown) passes through the transmitting station 10a ', the plurality of relay stations 10b',...
It is articulated. Then, between the transmitting station 10a 'and the first-stage relay station 10b', between the second-stage relay station 10b 'and the last relay station 10m', relay stations connected to each other, and finally, the relay station 10m ' , Between the outermost peripheral surface of the transmission cable 103A penetrating each station, and the distribution type optical fiber thermometer TH1, TH2,... Shown in FIG.・ ・, THm is attached.

Referring to FIG. 19A, the distributed optical fiber thermometer TH1 will be briefly described. The optical fiber thermometer TH1 has a clad CL on the outer periphery of a core CR,
When a pulsed laser beam is incident on the incident end IT of the optical fiber thermometer TH1 which is heated at multiple points along its longitudinal direction, Raman is applied at various points of the optical fiber thermometer TH1. Scattered light (frequency fluctuates) is generated, but the intensity of Raman scattered light has temperature dependence. When the backscattered light is detected, the time from when the pulsed light is incident to when it returns is different depending on the position where the Raman scattered light is generated.
The temperature of the optical fiber thermometer TH1 is obtained for each position, and the temperature distribution along the longitudinal direction of the optical fiber thermometer TH1 can be obtained. The temperature measurement range of this type of optical fiber thermometer is, for example, −200 ° C. to 500 ° C., and a temperature distribution up to a length of 30 km can be measured.

In the present invention, the optical fiber thermometer T
It is not always necessary to detect the temperature distribution along the longitudinal direction of H1. The pulse laser light whose propagation speed fluctuates according to the seawater temperature on the outer periphery of the distributed optical fiber thermometer TH1 may be simply detected. Therefore, in the present invention, the pulse laser light Sc is input to the input end IT of the optical fiber thermometer TH1, and the transmitted light pulse or the forward scattered light pulse is also detected at the output end OT.

As shown in FIG. 18, each of the measurement operation devices 800 provided in each of the relay stations 10b '... And the receiving station 10n' is transmitted from the ground station via the cable 103A. A reference light pulse generator 801 which is energized by the drive pulse DS to generate a reference light pulse.
And component detection units 802 and 803, and a measurement calculation unit 804.

The first component detector 802 receives the reference light pulse SP emitted from the reference light pulse generator 801 and the pulse laser light Sc emitted from the emission end of the optical fiber thermometer TH1. A first component light pulse signal indicating a phase difference between the two pulses is obtained with reference to the light pulse SP, converted into an electric signal, input to the measurement operation unit 804, and converted into a digital electric signal. Similarly, the second component detection unit 803 also operates as the reference light pulse generation unit 801.
A reference light pulse SP emitted from the light source and a pulse laser beam Sw transmitted through the sea, which will be described later, are incident, and a second component light pulse signal indicating a phase difference between the two pulses is obtained with reference to the reference light pulse SP. Is converted into an electric signal,
4 and converted into a digital electric signal. Then, the measurement calculation unit 804 compares the phase difference signal indicating the optical path length of the pulse Sc with the phase difference signal indicating the optical path length of the pulse Sw, and outputs the phase difference signal indicating the difference between the two optical paths to the cable 103A.
To the ground station via.

The configuration of the transmitting station, relay station, and receiving station shown in FIG. 17 differs from that described with reference to FIGS. The difference is that the temperature correction is performed based on the phase difference measurement indicating the optical path difference between the pulse laser beam Sc propagating through the distributed optical fiber thermometer and the pulse laser beam Sw passing through the sea.

Next, referring to FIGS. 17 to 19,
The identification of the presence / absence of a fault by the distributed optical fiber thermometer will be described.

First, the laser light source 4 of the transmitting station 10a 'is energized by the driving pulse DP transmitted from the ground station via the cable 103A. The pulse laser beam Sc is divided into two by the branch fiber described above (step S11), and the distributed optical fiber thermometer T is transmitted from the transmitting station 10a '.
H1 is propagated (step S14), and the connected relay station 10
The drive pulse DP similarly transmitted from the ground station to the component detection unit 802 of the measurement / calculation device 800 for b ′ is input to the reference light pulse generation unit 801, and the reference light pulse SP synchronously generated therefrom Also incident and pulse Sc
And a phase difference between the reference phase pulse SP and the reference phase pulse SP.

On the other hand, the other pulsed laser light Sw that is split by the prism 5 and transmitted through the sea is projected into the sea through the optical amplifier 6 and the light transmitting window 3 of the transmitting station, and then transmitted to the relay station 10b '. After passing through the light receiving window 3, the light is branched by the prism 5 and is incident on the component detection unit 803 of the measurement and calculation device 800 of the relay station 10 b ′. The synchronously generated reference light pulse SP also enters, and both pulses Sw
A phase difference between the reference pulse SP and the reference light pulse SP is detected, and is input to the measurement calculation unit 804 as a second phase difference signal, and is converted into a digital value. Then, the measurement calculation unit 804 compares the first phase difference signal, that is, the signal indicating the optical path length of the pulse Sc, with the second phase difference signal, that is, the signal indicating the optical path length of the pulse Sw, and compares them. A signal indicating the phase difference of the signal is output and transmitted to the ground station via the transmission cable 103A.

Similarly, between the relay station 10c '(not shown) and the opposite relay station 10d',..., And finally, between the relay station 10m 'and the receiving station 10n', The digital value indicating the phase difference between the optical pulse SP and the underwater transmission pulse Sw, and the digital value indicating the phase difference between the reference optical pulse PS and the pulse Sc propagating through the distributed optical fiber thermometer THm are transmitted via the cable 103A to the ground station. Is transmitted to

Thus, from each of the measurement calculation devices 800,..., The transmission optical path length of the laser light Sc propagating through the distributed optical fiber thermometer TH1 and the transmitted light path length of the laser light Sw in the sea between the opposing stations are determined. A phase difference signal indicating the optical path difference is output.

When cold water or hot water is interposed only between two opposed stations, the light pulse Sc is affected by only the temperature of hot water or cold water via the distributed optical fiber thermometer TH1. As a result, the propagation speed of the light pulse fluctuates,
Since the light pulse Sw transmitted through the seawater is output after receiving a change in the propagation speed due to the influence of the seawater temperature, the temperature dependence of both optical paths is canceled. Therefore, at the time of the previous measurement, that is, a phase difference signal indicating the optical path difference between both optical path lengths at the measurement time t ₁ ,
That is, the first relay station 10b 'facing the transmitting station 10a'.
The value Z1 of the optical path difference between the optical path lengths of both pulses Sc and Sw
The value Z2 of the optical path difference between the optical path lengths of both pulses Sc and Sw between the leading relay station 10b 'and the opposite relay station 10c'.
Output the value Zm of the optical path difference between the optical path lengths of both the pulses Sc and Sw of the relay station 10m 'and the receiving station 10n' at the last stage (step S15); The data is transmitted to the data processing device and stored in the memory. Then, both the optical path length of the phase difference signal Z1' in the measurement time t _2, Z2 ', and it outputs the ··· Zm' (step S16), and transmits same to the data processing apparatus on the ground observation station, in the memory Remember.

Therefore, for example, hot water between two opposed stations,
Or, when cold water is interposed, but hot water or cold water is not interposed between the other stations, that is, even if the seawater temperature between the stations is not the same, the phase difference at the measurement time t ₁ (at the start of observation) signals Z1, Z2, and · · · Zm, the phase difference signal Z1 of the measurement time t ₁ than after the predetermined period of time measured at t ₂ ', Z2',
.. Zm 'are individually compared (step S17), and Zm'
If there is no difference in the numerical value of the set of 1 and Z1 ', and there is no difference in the numerical value of the set of Z2 and Z2', if there is no significant difference in the numerical value of the set of Zm and Zm ', It is determined that the distance has not changed significantly, or the fault has not been activated, and no significant crustal deformation has been observed (step S1).
9) If a significant difference occurs in any one set of numerical values, it is determined that some abnormality such as fault activity has occurred between two opposing stations in the set in which the difference has occurred (step S1).
8). Then, display and printing of the presence / absence of horizontal distortion, and the measured values of the water pressure, flow velocity, flow direction, water temperature (see FIG. 1) measured by the temperature sensor 13, the refractive index, and the salt concentration measured in step S 12 are performed. (Step S20), Step S
Returning to step 11, the above processing is executed.

Note that the first-stage prism 5 in the relay station 10b 'shown in FIG. 17 is removed, and the measurement arithmetic unit 800 is provided at this position. Then, instead of the optical amplifier 6 located on the back side of the prism 5, the laser light source 4 that emits light simultaneously with the laser light source 4 of the transmitting station based on a command signal from the ground station is provided. It is also possible.

Next, as shown in FIG. 20, FIG.
6, the top surface of each pressure-resistant vessel 1 of the transmitting station 10a, the relay station 10b,..., And the receiving station 10n is formed in a frusto-conical shape, and the bottom layer flow in the direction directly above (in the sea surface direction) or obliquely upward. In order to detect the flow velocity distribution, a plurality of ultrasonic transmitters / receivers 201,... Are provided in parallel, and further, in order to detect the flow velocity distribution of the bottom layer flow on both side surfaces of each station, each side surface of the four sides of the eave 2 is detected. An ultrasonic transceiver 202 is provided for each. The ultrasonic transceivers 201,... And the ultrasonic transceivers 202,... Of the transmitting station 10a, the relay station 10b, and the receiving station 10n periodically transmit ultrasonic waves toward the sea. Receive the reflected wave from. This ultrasonic transmission wave and its reception wave are converted into electric pulses, and transmitted to the data processing device of the ground station via the outer cable 103A. Then, the presence or absence of the Doppler frequency displacement and the magnitude thereof are measured, and each station is measured. Detects the velocity of the surrounding bottom laminar flow. Note that the above-mentioned ultrasonic transceiver is replaced with the above-described ultrasonic transceiver shown in FIG.
Of course, it is also possible to provide the underwater distance measuring device shown in FIG.

Next, the propagation time of the laser light measured at τ1 when the reference amount is transmitted from the transmitting station at the head of the measurement line to the receiving station at the end via the relay station, and measured at τ2 after the elapse of a predetermined time. The third embodiment of the present invention adopts a temperature correction method that checks the propagation time and detects the presence or absence of a fault without being affected by the uniform temperature fluctuation of the entire survey line. This will be described with reference to FIGS. Note that the third embodiment described above differs from the first embodiment only in the temperature correction method, and other configurations, that is,
Transmitting station, relay station, and receiving station, armored cables connecting these stations, various sensors installed in each station, optical amplifiers,
Built-in instruments such as optical power splitting couplers, and survey lines AA,
The BB optical pulse transmission method, as shown in FIG. 9, is all the same in terms of obtaining the propagation time width of each photoelectric conversion pulse train extracted by branching the optical pulse to be transmitted to each station. Referring again to FIG. 9, the data processing block for temperature correction shown in FIG.
22 based on the flow chart of the temperature correction data processing shown in FIG.
The point that the temperature correction can be performed as shown in FIG.

For example, the sum of the respective pulse propagation time widths ΔT between the stations during observation of the measurement line AA at the water temperature t ₅ ° C and the measurement line BB at the water temperature t ₆ ° C, that is, the measured propagation time T ₅ as the reference propagation time, calculates the T _6, data processing for correcting the variation of the propagation velocity of the light pulse which these measured propagation time T _5, T ₆ is varied in response to temperature variations of the seawater and measuring lines AA, distribution of measuring lines BB Regarding the data processing device that measures the refractive index, water temperature, water pressure, flow direction, flow velocity, and salinity of seawater at the installation position, refer to the functional block diagram shown in FIG. 21 and the flowchart for executing the control shown in FIG. I will explain it.

FIG. 21 is a functional block diagram of a microcomputer or a personal computer that executes a control program for data processing described below. To explain this functionally, this data processing device is shown in FIG.
As shown in (C), photoelectric conversion pulses P _a , P _b , which are sequentially transmitted from each pressure vessel 1 on the sea floor to the ground station,
P _c, comprising a detection unit for sequentially capturing · · · P _n, then the set of pulse P _a P _b between the propagation time width [Delta] T _ab, P
and _b P _c between the propagation time width [Delta] T _bc, a counter section for counting the ···· P _m P _n propagation time width [Delta] T _mn between, and stores the respective propagation time width into the memory. Then, the adding unit, the sum of the propagation time width measuring line AA, ie, calculates the measured propagation time _{T As = ΔT ab + ΔT bc} + ··· + ΔT mn as reference propagation time, is stored in the memory.

By the way, the propagation velocity v of light in water is v =
Denoted by C ₀ / n, where C ₀ is the speed of light 3 in vacuum
× 10 ⁸ (m / s), n indicates the refractive index of water. As is well known, the refractive index n is determined by temperature, salt concentration,
It depends on the situation such as density, and is represented by a function n (n∝F (density, temperature, salt concentration, etc.)), that is, refraction when the temperature t is a standard temperature of 4 ° C. as shown in FIG. Since the refractive index n is the highest, and has a characteristic that it decreases as the temperature t rises or falls above 4 ° C., the light propagation velocity v in water having a functional relationship with the refractive index is 4 ° C. The light propagation speed v shows the above characteristics, and the propagation time T also decreases as the temperature t rises and falls around 4 ° C. It shows the characteristics of

Therefore, when measuring the reference amount τ₁At the survey line
AA seawater temperature t_As° C and the refractive index n at that temperature_As
Are actually measured by the temperature sensor 13 and the refractometer 12, respectively.
In the correction unit, the measured refractive index n_AsWith the above equation (v = C₀
/ N) into n _AsLight in seawater at ℃
Luth propagation speed v_As(M / s) and calculate these values
Is the initial temperature t_As° C, initial refractive index n_As, Initial propagation velocity v_As
As well as
Pulse signal P transmitted from the station_a, P_b, P_c,
..P_nSum T of each propagation time width ΔT between_AsIs the initial propagation time
As a memory. In addition, about survey line BB
Is also not shown, when measuring the reference amount τ₁Seawater temperature,
The measured refractive index and the calculated light pulse propagation velocity
And the initial temperature t_Bs° C, initial refractive index n_Bs, And initial propagation speed
Degree v_BsTo the memory as
Loose signal P '_a, P '_b, P '_c, ... P '_nBetween each
Sum T of propagation time width ΔT '_BsWith initial propagation time as memory
To be stored.

Next, at the measurement line AA, the measured water temperature measured at the measurement time τ ₂ after the elapse of a predetermined time from the measurement of the reference amount τ ₁ is represented by t
_When the measured refractive index is n ₅ at ₅ ° C., the correction unit calculates the calculated propagation velocity v ₅ of the light pulse in water by the arithmetic expression v = C ₀ / n as described above. In the adder,
Adding the respective propagation time ΔT by obtaining the measured propagation time T ₅ in the measurement time tau ₂ after the reference measuring determined. Relationship between the actually measured propagation time T ₅ , the calculated propagation velocity v ₅ , the initial propagation time v _As of the light pulse at the initial temperature t _As ° C. at the time of the reference amount measurement τ ₁ of the measurement line AA, and the initial propagation time T _As Is represented by the following equation: V = L (distance) / T (propagation time)
If the times τ1 and τ2 are close, ie, (τ
When the absolute value of 1−τ2) is small, the distance L is considered to be constant, and is represented by L = V · T. Therefore, it is represented by the relational expression v _As · T _As = v ₅ · T _5. . Therefore, the correction unit substitutes v ₅ , T ₅ , and v _As for the arithmetic expression T _As = (v ₅ · T ₅ ) / v _As = T _As5 obtained from this relational expression to obtain T _As , that is, at the time of measurement. τ
The measured propagation time T ₅ at the measured water temperature t ₅ ° C of ₂ is calculated as the propagation time T _As5 temperature-corrected at the initial temperature t _As ° C of the reference amount measurement time τ ₁ . T _As described above, that is, T
_As5, as shown in FIG. 22, the initial propagation time in the actual measurement the measured propagation time T ₅ of the water temperature t ₅ ° C., the initial temperature t _As ° C. of the reference measuring time tau ₁ of measuring line AA in the measurement time tau ₂ described above T _It is stored in a memory as a propagation time T _As5 indicated by temperature-corrected _As . Next, the temperature-corrected initial propagation time T _As5 is compared with the initial propagation time T _{As of} the reference amount measurement time τ ₁ stored in the memory by the comparison unit, and if there is no difference, the horizontal distortion change on the sea floor is observed. It is determined that the horizontal distortion has not occurred, and if there is a difference, it is determined that the horizontal distortion has changed. In this way,
The discrimination signal, together with the measured data of the water temperature, water pressure, flow direction, flow velocity, and salinity concentration measured by the refractometer 12, the temperature sensor 13, the water pressure sensor 14, the flow direction meter 15, the flow velocity meter 16, and the salinity concentration meter 17, together with the printer, Send to CRT.

Regarding the measurement line BB, when the measured water temperature at the time of measurement τ ₂ after the reference amount measurement is t ₆ ° C and the measured refractive index is n ₆ , the seawater of the light pulse calculated by the arithmetic expression v = C ₀ / n The initial velocity t _Bs ° C and the initial refractive index n stored in the memory at the measured propagation time T ₆ obtained by adding the medium velocity v ₆ , each propagation time ΔT, and the measurement time τ ₁ of the measurement line BB. of light pulses which is calculated in the _Bs and the initial propagation velocity v _Bs, v _Bs · T
_Bs = v ₆ · T ₆ arithmetic expression T _bs determined from the relationship equation _{= (v 6 · T 6)} / v by substituting _bs = T _BS6 calculating the T _bs. The measured propagation time T _Bs of the measurement line BB at the measurement time τ ₂ at the measured water temperature t ₆ ° C.
₆ is the initial temperature t of the measurement line BB at the time of measuring the reference amount τ ₁ .
_It is stored in a memory as a propagation time T _{Bs6 obtained} by temperature-correcting the initial propagation time T _Bs at _Bs ° C. Then, the temperature-corrected propagation time T _Bs6 and the initial propagation time T of the reference amount measurement time τ ₁
The presence or absence of significant distortion is determined based on the comparison result in the comparison unit with _Bs .

Next, the operation of the measurement lines AA and BB to which the third embodiment of the present invention is applied over the tomographic planes 60 and 61 shown in FIGS. 6 and 8 will be described. Now, the propagation light pulse generated from the laser light source 4 of the optical transmission station 10a is branched by the preceding branch coupler 5A, and the attenuation due to the branch is made equal to the light intensity of the light pulse from the laser light source 4 by the optical amplifier 6. The optical pulse M _a that has been amplified to
(A)) is incident on the subsequent branch coupler 5B,
The amount of attenuation due to the branch is amplified to the light intensity of the light pulse from the laser light source 4 (FIG. 9B), and transmitted through the light transmission window 3 to the light transmission window 3 of the relay station 10b at the next stage. . Also,
Is branched by the branch coupler 5A, the other branch pulsed light as observation light pulses, transmits the pulse P _a photoelectrically converted by the photoelectric converter 9 to the ground station (not shown) via a transmission cable 103A (FIG. 9 (C)).

The optical pulse received through the optical transmission window 3 of the repeater 10b at the next stage is amplified by the optical amplifier 6 to the same intensity as the optical intensity of the optical pulse from the laser light source 4, and is branched by the branch coupler 5B. Is input to the optical amplifier 6 and further transmitted through the light transmission window 3 to the next-stage relay station. In this way, the branched pulse light is successively transmitted to the subsequent relay station. I do. The other branch pulse light M _b branched by the branch coupler 5A of the relay stations 10b,.
M _c, ··· M _m electricity by photoelectric converter 9 pulses P _b, P _c, converted into · · · P _m, the transmission cable 103
To a ground station (not shown). In the receiving station 10n at the last stage, one of the branched pulse lights incident through the light transmission window 3 is amplified by the optical amplifier 6 to the same intensity as the light intensity of the optical pulse from the laser light source 4, and branched by the branch coupler 5C. photoelectric conversion pulse P _n of the other branched light pulses M _n was
Is transmitted via the transmission cable 103 in the same manner.

On the other hand, as shown in FIG. 7 and FIG.
The pulse light branched by the 0a branch coupler 5B is input as a propagation light pulse to the optical amplifier 6 in the preceding stage via the light transmission window 3 of the head transmitting station 20a of the adjacent measurement line BB, and the light intensity of the laser light source 4 light amplified one of the split pulse light _M'a incident on the branching coupler 5A in the same intensity and incident to one of the branch pulsed light after the optical amplifier 6, an optical amplification in the optical intensity and the same intensity of the laser light source 4 Then, the light is transmitted to the next-stage relay station 20b via the light transmission window 3. Then, the other branch pulsed light branching coupler 5A as an observation light pulse, and sends it into an electric pulse _P'a by the photoelectric converter 9. Thus, one of the branched optical pulses is transmitted to the last receiving station 20n one after another via the following relay station. On the other hand, the branch coupler 5 of the relay station 20b,.
The other branch pulse light M ′ _b , M _c ′,
.., M ′ _n is converted by the photoelectric converter 9 into electric pulses P ′ _b ,
Are converted to P ′ _c ,... P ′ _m , P ′ _n and transmitted to a ground station (not shown) via the transmission cable 103.

Next, refer to the flowchart shown in FIG.
And processing of detection data transmitted from each station
explain. In the data processing device of the ground station, FIG.
As shown, when measuring the reference amount τ₁In the transmission of the survey line AA
From the transmitting station 10a, the relay station 10b,..., The receiving station 10n
Photoelectric conversion pulse P transmitted one after another_a, P_b,
P _c, ... P_nAnd the top transmitting station 20a of the measurement line BB, middle
..,..., Successively transmitted from the receiving station 20n.
The transmitted photoelectric conversion pulse P '_a, P '_b, P ' _c,
... P '_n(Step S1)
1) The water temperature at the installation position of the measuring lines AA and BB is
Thus, for example, t_Five° C, t₆℃, refractive index
By means of the refractometer 12, for example, n_Five, N₆Real
Measurement (step S12), and further, the water pressure sensor 14,
Lines are set using a direction meter 15, current meter 16, and salt concentration meter 17.
Location water pressure, ocean current direction, ocean current velocity, salinity data
The data is fetched (step S13). Next, from survey line AA
Pulse P_aP_bPropagation time width ΔT between_ab, Pulse P_bP
_cPropagation time width ΔT between_bc, ..., Pulse P_mP_nwhile
Propagation time width ΔT_mnAnd the pulse P 'from the measurement line BB_aP
´_bPropagation time width ΔT 'between_ab, Pulse P '_bP '_cAmong
Propagation time width ΔT '_bc, ..., pulse P '_mP '_nwhile
Propagation time width ΔT '_mnIs counted by the counter section,
Each propagation of the AA from the transmitting station 10a to the receiving station 10n
Sum of time widths, that is, measured propagation time T_Five= ΔT _ab+ ΔT
_bc+ ... + ΔT_mnAnd the relay station of the survey line BB
Total of each propagation time width from 20a to receiving station 20n
Sum, ie, the measured propagation time T₆=, ΔT ′_ab+ ΔT '_bc+
... + ΔT '_mnIs calculated and stored in the memory (step
S14). Then, the detected water temperature t of the measurement line AA_FiveCompatible with ° C
Measured refractive index n_FiveIs calculated by the following equation: v = C₀Substitute / n for n
And the initial propagation speed v of the light pulse_FiveIs calculated. Measurement line BB
Then, the detected temperature t₆Measured refractive index n in ° C₆Is the arithmetic expression
v = C₀/ N to n₆To
It is calculated (step S15).

Next, the measured propagation time T on the survey line AA_Five
And the measured temperature t_Five° C, the measured refractive index n_FiveCalculation in
Seeding speed v_FiveAnd the survey line AA stored in the memory in advance
When measuring the reference amount of τ₁Initial temperature t_As℃
The initial propagation velocity v of the light pulse_AsAnd the initial propagation time T_As
And the expression T_As= (V_Five・ T_Five) / V_As To T_AsIs calculated. This T_AsIs the actual line AA
Temperature measurement t_FiveMeasured propagation time T in ° C_FiveIs the basis of the survey line AA
At the time of reference value measurement τ₁Initial temperature t_AsInitial propagation time in ° C
(T_As) And the propagation time T obtained by temperature correction_As5As
It is stored in the memory (step S16). Thus the measurement ends
After completion, the initial temperature t_AsInitial propagation time T in ° C_AsAnd
Τ when measuring the reference amount of line AA_TwoStored in the memory of
Initial temperature t _AsPropagation time corrected to the propagation time in ° C
Interval T_As5(Step S17), and T_AsAnd T_Fiveof
If there is no significant difference between them, the horizontal distortion does not change (step
Step S19), if there is a significant difference, the horizontal distortion has changed.
Can be determined (step S18). Asked in this way
Seawater temperature, water pressure, current direction, flow velocity, salt concentration
(Step S)
20). Then, the process jumps to step S11, where the data
Repeat the process.

Similarly, for the measurement line BB, T _Bs is calculated based on the above equation. This T _Bs is obtained by calculating the actual propagation time T ₆ of the measurement line BB at the measured temperature t ₆ ° C by the initial propagation time T of the reference line BB at the measurement time τ _{1 at} the initial temperature t _Bs ° C.
And stores it in the memory as a propagation time TB ₆ that temperature compensation to _bs. Then, to determine the presence or absence of a change in the horizontal distortion based on the result of comparison between the initial propagation time T _Bs and the temperature corrected propagation times T _BS6. Since the refractive index n is also a function of the salt concentration as described above, even when the salt concentration fluctuates and the speed fluctuation of the laser pulse light propagating in the seawater occurs, the salt concentration at the time of the reference amount measurement τ ₁ is measured. and the refractive index of the previous variation, after the reference propagation time measurement of the measurement time tau ₂ actually measuring the refractive index after salinity variation, as already mentioned, during the reference measuring time tau ₁ at refractometry a subsea propagation velocity v ₁ and transect the measured propagation time T ₁ of the pulse, the time of refractive index measurement at the measurement time tau ₂ after the reference propagation time measured and sea propagation velocity v ₂ and measuring lines of the measured propagation time T ₂ of the pulse It is obtained and substituted into the above-mentioned arithmetic expression, and it is possible to correct the fluctuation of the light pulse propagation velocity in the sea based on the fluctuation of the salt concentration, and to accurately identify the presence or absence of significant fault activity or crustal deformation.

When the reference amount is measured, τ₁Later measurements are described above
At the time of the second measurement τ_TwoNot only after a certain period of time
τ_Three, Τ_Four, ..., τ_nMeasurement of reference amount is repeated
Time τ ₁And τ_Three, Τ_Four, ..., τ_nof
Observe by comparing the values obtained at the time of each measurement individually.
Of course. Further, the temperature compensation shown in FIGS.
The correct method is described in FIGS. 13, 14, 15 and 2 described above.
0 can be applied to the apparatus shown in FIG.

Finally, on the measurement lines AA and BB shown in FIGS. 6 to 8, the optical transmission stations 10a and 20a to the relay station 10b.
.., 20b..., The last receiving station 10n,
Uses a single optical path measurement system that transmits the propagation laser light in the forward direction toward 20n, but can transmit the laser light in the reverse direction from the receiving stations 10n and 20n to the optical transmitting stations 10a and 20a. Since the measurement accuracy can be improved by the above, an optical distance measuring apparatus including a reciprocating optical path optical measuring system will be described with reference to a plan view 24 schematically showing the configuration.

In contrast to the serial arrangement of the outgoing branch coupler 5B and the optical amplifier 6 of the transmitting station 10a on the measurement line AA, the multipath serial coupler 5A and the optical amplifier 6 are arranged in parallel, and the receiving station 10b. ..Optical amplifiers 6 and branch couplers 5 for the outbound path
A, the serial arrangement of the optical amplifier 6, the optical amplifier 6 for multiple paths, the branch coupler 5A, and the serial arrangement of the optical amplifier 6 are arranged in parallel, and further, the optical amplifier 6 for the forward path of the receiving station 10n, In contrast to the serial arrangement of the branch coupler 5C and the optical amplifier 6, the serial arrangement of the multi-path optical amplifier 6, the branch coupler 5C and the optical amplifier 6 is arranged in parallel, and the laser light is emitted from the optical amplifier 6 for the forward path. Side and the space between the entrance side of the optical amplifier 6 for the return path,
Prisms PR1 and PR2 for refracting the propagation laser light from the forward optical amplifier 6 into the backward optical amplifier 6 are provided.

Similarly, the branch coupler 5A for the return path and the optical amplifier 6 are arranged in parallel with the branch coupler 5A for the forward path and the optical amplifier 6 of the head transmitting station 20a of the measurement line BB.
The serial arrangement of the optical amplifier 6, the branch coupler 5A, and the optical amplifier 6 for the multi-path is arranged in parallel with the serial arrangement of the optical amplifier 6, the branch coupler 5A, and the optical amplifier 6 for the forward path b. Furthermore, the serial arrangement of the multi-path optical amplifier 6, the branch coupler 5C, and the optical amplifier 6 is arranged in parallel with the serial arrangement of the optical amplifier 6, the branch coupler 5C, and the optical amplifier 6 for the forward path of the receiving station 20n. And a prism for refracting and propagating the propagation laser light from the forward optical amplifier 6 to the backward optical amplifier 6 in the space on the outgoing optical amplifier 6 at the laser light emitting side and the incoming side of the backward optical amplifier 6. PR1 and PR2 are provided. Of course,
A photoelectric converter 9 (not shown) is provided on a branch path of the branch couplers 5A to 5C of the measurement line AA and the measurement line BB. In addition, the code | symbol 3 in a figure shows a light transmission window.

With the formation of the optical measurement system for the reciprocating optical path, the laser light for propagation from the laser light source 4 on the measurement line AA passes through the branch coupler 5B and the optical amplifier 6, and as shown by the arrow, the relay station 10b at the next stage. , Via the optical amplifier 6, the branch coupler 5C, and the optical amplifier 6 in the final receiving station 10n.
, Are refracted by the prisms PR1 and PR2, then pass through the optical amplifier 6, the branch coupler 5C, and the optical amplifier 6, pass through the relay stations 10b,.
The light enters the branch coupler 5A via the optical amplifier 6 of FIG.

The measurement line BB is also used as indicated by the arrow.
The propagation laser light branched by the branch coupler 5B of the transmission station 10a of A enters the optical amplifier 6 through the light transmission window 3 of the head transmitter 20a of the measurement line BB, and further the branch coupler 5B
A, the light is sequentially transmitted to the next-stage relay station 20b... Via the optical amplifier 6 and then to the prisms PR1 and PR2 via the optical amplifier 6, the branch coupler 5C, and the optical amplifier 6 of the receiving station 20n.
, And is emitted from the optical amplifier 6, the branch coupler 5C, and the optical amplifier 6, and is transmitted to the next-stage relay station 20b.
Finally, the optical amplifier 6 and the branch coupler 5 of the head transmitting station 20a
A. In the meantime, the branch couplers 5A to 5C in the reciprocating optical paths of the measurement line AA and the measurement line BB transmit the laser light to the not-shown photoelectric converters 9 to obtain measurement data in the reciprocation optical path measurement system. Such a reciprocating optical path measuring system is shown in FIGS. 13, 14, and 22.
The present invention is also applicable to the apparatus of the present invention shown in FIG.

[0127]

According to the present invention as mentioned above, according to the present invention, the data processing apparatus, the reference value for each measurement time t ₁ and a measurement time t ₂ after a predetermined time, one of the opposite station Short-term average correction amount of any one parameter g in the station <g
> As <δL (parameter)>, and the measurement time t ₁ ,
The installation distance L between the opposing stations before correction is determined from the product of the propagation speed v of the light pulse in water at t ₂ and the propagation time width ΔT of each set of photoelectric conversion pulse trains between the opposing stations, and obtains a true between the opposing station installation distance L after correction in the measurement time t ₂ from the opposite station between the installation distance L and the short-term average correction amount before correction <[delta] L (parameters)> sum _t2) at t ₂ when, also (between the opposing station installation distance L and the short-term average correction amount before correction in the measurement time t ₁ <[delta] L (parameter)> _t1 sum of) the true opposite station between the installation distance L _t1 determined after correction in the measurement time t ₁ from further, the opposite station on the basis of the difference between (among true opposite station after correction in the measurement time t ₂ the installation distance L _t2) and (inter true opposite station after correction in the measurement time t ₁ the installation distance L _t1) The presence or absence of distortion between them,
(True counter-station installation distance L after correction at measurement time t ₂
The value of _t2, and the difference) of the true value of the counter station between the installation distance L _t1 corrected in the measurement time t _1, (a value between the true opposite station after correction in the measurement time t ₂ the installation distance L _t2 and the average value of the true value of the counter station between the installation distance L _t1 corrected in the measurement time t ₁₎
From the ratio of the, or, (the difference between the measured time the true value of the counter station between the installation distance L _t2 after the correction in t _2, and the true value of the counter station between the installation distance L _t1 corrected in the measurement time t ₁ ) And (true corrected installation distance L _t1 between opposing stations at measurement time t ₁ ) to calculate the amount of distortion generated between the opposing stations. It is possible to accurately determine whether significant distortion has occurred between the opposing stations that form the survey line without being affected by the fluctuations in the measurement line, and to calculate the amount of distortion that occurs between the opposing stations. Becomes

According to the invention of claim 2, "added value of each short-time average correction amount <g> of a plurality of parameters g such as water temperature in one of the opposing stations" or "each station of the opposing station" Short-term average correction amount <g> of a plurality of parameters g at
ΔL ′ (parameter)> as the short-time average correction amount for correcting the apparent fluctuation of the installation distance L between the opposite stations before the correction.
Is applied so that a more accurate short-time average correction amount can be obtained than when one parameter g is used.

According to the third aspect of the present invention, when the reference amount is measured τ
₁Initial temperature t of water temperature_AsInitial refractive index n of water at ℃_As
Is calculated by the following equation: v = C₀/ N substitute for n
Initial propagation velocity v of pulse_AsAnd the actual number of each set between stations
Initial propagation time T, which is the sum of measured pulse propagation time width ΔT_AsWhen
Is stored in the storage means, and the time τ_TwoMeasurement of
Water temperature t_nMeasured refractive index n in ° C_nIs calculated in the same way
Propagation speed v_nAnd measured pulse propagation for each set
Measured propagation time T_nAt the time of measurement τ_Two
Measured propagation time T_nAnd the propagation velocity v_nAnd the initial propagation speed
v_AsAnd the arithmetic expression T_Asn= (V_n・ T_n) / V_ASAssigned to
T_AsnAt the time of measurement τ_TwoMeasured propagation time T_nTo
Initial temperature t_AsPropagation time T, temperature corrected to ° C_AsnNote as
Τ₁Initial propagation time T
_AsAnd propagation time T corrected for temperature_AsnAnd the contrast
Configure to identify the presence or absence of horizontal distortion based on the result
Even if the entire survey line is subject to uniform fluctuations in water temperature, etc.
When measuring reference amounts without being affected by fluctuations in light propagation speed
τ₁Initial propagation time T_ASAnd the measurement time τ after the reference amount measurement _Two
Propagation time T corrected for effects of water temperature, etc._ASnPair with
Ratio allows accurate measurement of the propagation time between baselines
In addition, provide the refractive index of water around the survey line installation, temperature data, etc.
Can be shown.

According to the fourth aspect of the present invention, since the round-trip optical measurement system is provided on the measurement line, measurement data in the forward and reverse directions of the light pulse propagation direction can be obtained, thereby improving the measurement accuracy. Is peeled off.

According to the fifth aspect of the present invention, a large number of survey lines consisting of a head transmitting station, a relay station, and a receiving station are laid in parallel on a survey line, and the propagation line branched from the optical pulse transmitting station on the survey line is provided. The optical pulse is optically coupled so as to be sequentially propagated to each of the leading transmitting stations of the plurality of survey lines, and light is transmitted from each of the leading transmitting stations of the survey line to the receiving station via the relay station of its own survey line. In addition, since the photoelectric conversion pulse from each station in a large number of survey lines is configured to be transmitted to the data processing device via the transmission cable, an observation network having a surface spread on the water bottom surface can be laid.

According to the invention of claim 6, a predetermined station in the above-mentioned survey line is a branch station, and a branch survey line consisting of a head transmitting station, a relay station, and a receiving station is laid in a plurality of directions from the branch station. As a result, the observation area on the water floor can be expanded in a similar manner.

According to the seventh aspect of the present invention, since observation stations are laid on the water bottom at each of the vertices of a large number of triangles, a water bottom observation area having a two-dimensional spread is similarly formed. Can be done.

According to the eighth aspect of the present invention, the photoelectric conversion pulse train is transmitted to the data processing device via the transmission cable, and the observation light pulse branched between the stations installed opposite to each other is set as one set. The pulse propagation time width ΔT is calculated separately for each of a plurality of clock pulses having different frequencies, so that the counting results of the pulse propagation time width ΔT for each set can be comprehensively compared. It is possible to obtain more accurate measurement values.

According to the ninth aspect of the present invention, the reference amount measurement time t
_A distributed optical fiber thermometer is added to the optical path length of the branch light pulse Sw passing through the water interposed between the opposing stations detected in ₁ and the transmission cable interposed between the opposing stations, and between the opposing stations. and the difference in optical path length of the split light pulse Sc to be transmitted through an optical fiber light path of the distributed optical fiber thermometer mediated measured during both pulse Sw is detected at the measurement time t ₂ after a predetermined time has elapsed since t _1, the Sc The difference between the two optical path lengths is compared with each other, and the presence or absence of distortion is determined based on the comparison result. Therefore, even if hot water or cold water is interposed between the opposite stations, both pulses Sw , Sc are affected by the same water temperature, so that the influence of the temperature on both light paths is eliminated, whereby even if the water temperatures between the opposite stations forming the survey line are different,
Without being affected by the occurrence of a fault, or
The presence or absence of existing fault activity can be accurately determined.

[Brief description of the drawings]

(A) is a partial cross-sectional view of the laser light transmitting station of the present invention, taken along the cutting line AA ′ shown in (B) and viewed from the direction of arrow P, and (B) is (B). It is a perspective view of the transmitting station shown to A).

FIG. 02 is a sectional view schematically showing an internal configuration of a relay station of the present invention laid on the sea floor.

FIG. 03 is a cross-sectional view of an outer cable including a transmission cable for transmitting data observed by a station installed on the sea floor to a ground station and a power supply line for performing one-side power supply.

(A) is a configuration diagram of an optical amplifier provided in a transmitting station, a relay station, and a receiving station, and (B) is a configuration diagram of an erbium-doped optical fiber amplifier.

FIG. 05 shows a branch coupler for branching optical power;
(A) is a side view of an optical coupler at a preceding stage provided in a transmitting station, (B) is a side view of an optical coupler provided at a subsequent stage of an optical coupler at a preceding stage of the transmitting station, and (C) is a side view of a final stage. It is a side view of the optical coupler provided in the receiving station.

FIG. 06 is a schematic configuration sectional view of each station along a measurement line AA shown in FIG. 08.

FIG. 07 is a schematic cross-sectional view of each station along the measurement line BB shown in FIG. 08.

FIG. 08 is an overall arrangement diagram of a first installation example of two sets of measurement lines including the optical distance measuring device of the present invention.

FIG. 9A shows an optical pulse train transmitted from each station of two sets of measurement lines, and FIG. 9B shows an attenuation of light intensity obtained by optically amplifying the attenuated light intensity to a laser light source emitted from a laser light source.
FIG. 3C is a waveform diagram showing two sets of branched photoelectric conversion pulse trains and a propagation time width between each pulse.

FIG. 10 is a functional block diagram of a data processing device that calculates a propagation time width of an optical signal between stations and identifies whether or not a significant distortion amount ε has occurred.

FIG. 11 is a graph showing a relationship between a measurement time and a distortion amount generated during the measurement time.

FIG. 12 is a flowchart of a data processing device that controls data processing.

FIG. 13 is a block diagram of a second installation example of the present invention in which a large number of measurement lines are branched and laid in multiple directions.

FIG. 14 is a block diagram of a third installation example in which a large number of measurement lines are laid in parallel on the sea floor.

FIG. 15 is a block diagram of a fourth installation example in which a plurality of triangles are laid at each vertex formation position on the seabed and have a two-dimensional spread.

16 is a diagram illustrating a trapezoidal region S of the observation network of FIG. 15 extracted and enlarged.

FIG. 17 is a diagram showing another optical system according to the present invention for detecting the occurrence of significant fault activity or crustal activity by eliminating the influence of the temperature when the temperature between the two opposing stations forming a part of the survey line is different. It is a block diagram of a type distance measuring device.

18 is a diagram illustrating a configuration example of a measurement operation device provided in each of the relay stations 10b ′... And the reception station 10n ′ illustrated in FIG.

19 (A) is a perspective view of a part of the distributed optical fiber thermometer, and FIG. 19 (B) is a flowchart showing execution of functions of the apparatus shown in FIG.

FIG. 20 is a diagram of a submarine arrangement of another optical distance measuring apparatus according to the present invention, in which an ultrasonic transceiver is provided in each station to observe the presence or absence of a bottom laminar flow, a situation, and the like.

FIG. 21 is a functional block diagram of a data processing device according to a third embodiment of the present invention which differs in a temperature correction method.

22 is a side line AA according to the third embodiment of the present invention provided with the data processing device shown in FIG. 21; a refractive index n of seawater around a standard temperature; a propagation speed v of an optical pulse in seawater; FIG. 7 is a diagram showing a change tendency of the light propagation time T and measured values before and after temperature correction.

FIG. 23 is a flowchart of a data processing device that executes data processing control of the device of FIG. 21;

FIG. 24 shows a measurement line AA and a measurement line BB shown in FIGS.
FIG. 2 is a block diagram of a schematic configuration for explaining a measurement system including a reciprocating optical path, as viewed from above.

FIG. 25 is a conceptual diagram of a measurement line laid on the sea floor and configured by a conventional optical distance measuring device.

FIG. 26 (A) is a layout diagram of conventional measurement lines individually arranged in two directions across a fault, and FIG. 26 (B) is a layout of conventional measurement lines arranged at one time orthogonally in two directions across a fault. FIG.

[Explanation of symbols]

10a ... transmitting station, 10b ... relay station, 10n ... receiving station, 12 ... refractometer, 13 ... temperature sensor, 14 ...
Water pressure sensor, 15 ··· current meter, 16 · · flow direction meter, 17 ·
・ Salt concentration meter, 5a, 5b, 5c ・ ・ Branch coupler,
6 '.. Erbium-doped optical amplifier, TH1 to TH (n
-1) ··· Distributed optical fiber thermometer, Sw ··· Pulse laser light transmitted through the sea, Sc ··· Pulse laser light transmitted through the distributed optical fiber thermometer, 201, 202 ···
Ultrasonic transceiver.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01V 1/22 G01C 3/06 G01V 8/10

Claims (9)

(57) [Claims] 1. A transmitting station for transmitting an optical pulse through a fault at the bottom of the water, a relay station for receiving the optical pulse and transmitting the light pulse to a next station, and receiving an optical pulse from the relay station. A measurement line is provided in which a receiving station at the final stage is disposed opposite to the receiving station at predetermined intervals, and a light beam for observation is transmitted from the transmitting station to the receiving station via the relay station. The pulse is branched, the photoelectrically converted pulse train, and the refractive index, salt concentration, and the water around each station installed detected by the sensor provided for each station.
Water temperature, water pressure, flow rate, and transmitted to the ground station and the detection data of the flow direction through the transmission cable, takes in the photoelectric conversion pulse train, when the reference measurement t ₁ and after a predetermined time has elapsed from the time of the reference measurement Measurement time t ₂
In the above, the photoelectric conversion pulses between the stations arranged opposite to each other are regarded as one set, and based on the obtained one-way pulse propagation time width ΔT between the opposite stations and the detected data, the horizontal distance between the opposite stations on the underwater base is determined. An optical distance measuring device including a data processing device for identifying the presence or absence of distortion, wherein the data processing device performs a measurement with respect to an installation distance L between the opposite stations at the measurement time t ₁ and the measurement time t ₂ . Refractive index, salt concentration, water temperature, water pressure, flow velocity, or flow direction parameter g that gives apparent fluctuation
Are repeatedly detected N times, and the following equation (2) is used to determine the propagation velocity v of the underwater light pulse between the opposing stations at the measurement time t ₁ and the measurement time t ₂ obtained by the following equation (1). Pulse propagation time width between stations Δ
By substituting T with each other, the installation distance L between the opposing stations before the correction at the measurement time t ₁ and the measurement time t ₂ is obtained. The respective short-time average correction amounts <g> at the measurement times t ₁ and t ₂ calculated by dividing the sum of N repeated detection values of one parameter g by N are represented by <δ
L (parameter)>, and the above <δL (parameter)> shown in the following arithmetic expression (3 ′) is the apparent installation distance L between the opposing stations before the correction at the measurement time t ₁ and the measurement time t ₂ . used is regarded as the short-term average correction amount for correcting the variation, according to the following arithmetic expression (4), between the opposed stations before correction in the measurement time t ₁ installation distance L and _(j) the short-term average correction amount <[delta] L
(Parameters)> sought installation distance L between the true opposite station corrected based on the sum of the _t1, by the following arithmetic expression (4 '), between the opposed stations before correction in the measurement time t ₂ installation distance L _{( j)} and short-term average correction amount <δ
L (parameters)> based on the sum of _t2 determined the true opposite station between the installation distance L after correction the true corrected in the (measured at t ₂ represented by the following arithmetic expression (5A), or (5B) from values between the opposite station installation distance L _t2) whether the distortion occurred between opposite station on the basis of the result of the difference between the value of (inter true opposite station installation distance corrected in the measurement time t ₁ L _t1) Identify and calculate the following equation (5A)
Based on, the above (the difference between the measured time the true value of the counter station between the installation distance L _t2 after the correction in t _2, and the true value of the counter station between the installation distance L _t1 corrected in the measurement time t ₁₎ , from the ratio between the (average values of the measured time between the true opposite station installation distance corrected in t ₁ and t ₂ L _t1 and L _t2), or on the basis of the following arithmetic expression (5B), the (time of measurement true value of the counter station between the installation distance L _t2 after the correction in t _2, and a true difference in the value of the counter station between the installation distance L _t1) after correction in the measurement time t _1,
The amount of strain occurring between the opposed stations from the ratio of the (true between the opposing station installation distance L _t1 corrected in the measurement time t ₁₎ [ε
(I, i + 1)] An optical distance measuring apparatus characterized in that _{t1 and} ^t2 are determined. Equation (1): v = C ₀ / n, where n is the measurement time t ₁
And the measured refractive index of water at each station at t ₂ , C ₀ is the light velocity in vacuum (3 × 10 ⁸ m / s), and v is the measurement time t ₁ and t
_2, which indicates the propagation speed of the optical pulse between the opposing stations in Equation (2): v × ΔT = L, where ΔT indicates the one-way propagation time width of the optical pulse between the opposing stations, Here, <g> is an average value of N measurements of each parameter g,
That is, the short-time average correction amount of each parameter g, <δL (parameter)>, is a short-time average correction amount for correcting an apparent variation of the installation distance L between the opposite stations before correction, i, (i
+1) is the i-th station, the (i + 1) -th station, δg _(j) and δ
L (parameter) _(j) represents a measure of the j-th of the N iterations detection, calculation formula (4): between true opposite station after correction in the measurement time t ₁ installation distance L = [L _t1 ^C (I, i + 1)] = (measurement time t
₁ the distance between the opposing stations before correction [L _(j) (i, i
+1); t = t ₁ ]) + (short-time average correction amount at measurement time t ₁ <δL (parameter)> _{t 1} ), Expression (4 ′): true inter-office after correction at measurement time t ₂ installation distance L = ^{_{[L t2 C (i, i +}} 1) ] = (opposite station between the installation distance before correction in the measurement time t ₂ [L _(j) (i,
i + 1); t = t ₂ ]) + (short-time average correction amount at measurement time t ₂ <δL (parameter)> _{t 2} ), Expression (5A): [ε (i, i + 1)] _t 1 ^{t 2} ≡ ｛(measurement The true installation distance between opposing stations after correction at time t ₂ [L _t2 ^C
(I, i + 1)]) − (True installation distance after correction at measurement time t ₁ [L _t1 ^C (i, i + 1)])｝ /
0.5 × ｛(true inter-station distance after correction at measurement time t ₁ [L _t1 ^C (i, i + 1)]) + (true inter-station distance after correction at measurement time t ₂ [ L _t2 ^C (i, i
+1)])}, the calculation formula (5B): [ε (i, i + 1)] _t1 ^t2 ≡ {(true opposite station between the installation distance corrected in the measurement time t ₂ [L _t2 ^C
(I, i + 1)]) − (True installation distance after correction at measurement time t ₁ [L _t1 ^C (i, i + 1)])｝ /
(True corrected inter-station distance [L _t1 ^C (i, i + 1)] after correction at measurement time t ₁ ). 2. The above-mentioned <δL (parameter)> is calculated at the time of measurement₁And measurement time t_TwoBefore correction
Time to correct the apparent fluctuation of the installation distance L between
As the inter-average correction amount, one of the above opposing stations
Short-term average correction amount of arbitrary parameters g <
g>, or any of the opposing stations
The short-term average correction amount <g> of the plurality of parameters g of
<Δ when the average value is calculated by dividing by 2
L ′ (parameter)>, and the above measurement time t is calculated by the following arithmetic expression (4A).₁Complement in
Installation distance L between the opposing stations in front_(j)And short-term average correction amount <δ
L '(parameter)>_t1At the time of the above measurement based on the sum of
t₁, The true installation distance L between the opposing stations after the correction is obtained, and the above measurement time t is calculated by the following arithmetic expression (4B)._TwoComplement in
Installation distance L between the opposing stations in front_(j)And short-term average correction amount <δ
L '(parameter)>_t2At the time of the above measurement based on the sum of
t_Two, The true installation distance L between the opposing stations after the correction is obtained, and is expressed by the following equation (5A) or (5B) (measurement time t_Two
Corrected inter-station distance L after correction in_t2) Value
(At the time of measurement₁Corrected inter-station distance L after correction in
_t1) Based on the result of the difference between
The presence or absence of occurrence is identified, and based on the following arithmetic expression (5A)
Then, (measurement time t_TwoTrue inter-station setup after correction in
Distance L_t2And the time of measurement t₁True after correction in
Installation distance L between opposing stations_t1) And the above (at the time of measurement t₁
And t_TwoCorrected inter-station distance L after correction in_t1Passing
And L_t2From the average value) or the following arithmetic expression (5B)
Based on (measurement time t_TwoTrue opposite station at
Installation distance L_t2And the time of measurement t₁After correction in
True distance L between opposing stations_t1Difference) and the above (during measurement)
t₁Corrected inter-station distance L after correction in_t1) With
The amount of distortion generated between the opposite stations based on the ratio [ε (i, i + 1)]
_t1 ^t22. The optical measurement according to claim 1, wherein
Distance device. Equation (4A): t at the time of measurement₁True opposition after correction at
Station installation distance L = [L _t1 ^C(I, i + 1)] = (at the time of measurement
t₁In the opposite station before correction [L_{(j )}(I,
i + 1); t = t₁]) + (At the time of measurement t)₁Short time in
Average correction amount <δL '(parameter)>_t1), Equation (4B): t during measurement_TwoTrue opposition after correction at
Station installation distance L = [L_t2 ^C(I, i + 1)] = (at the time of measurement
t_TwoIn the opposite station before correction [L_(j)(I,
i + 1); t = t_Two]) + (At the time of measurement t)_TwoShort time in
Average correction amount <δL '(parameter)>_t2), Equation (5A): [ε (i, i + 1)]_t1 ^t2≡ ｛(Measure
Time t_TwoOf the true installation distance between opposing stations [L_t2 ^C
(I, i + 1)]｝-(measurement t₁True after correction in
Installation distance [L_t1 ^C(I, i + 1)])｝ /
0.5 × ｛(at measurement t₁Between true opposing stations after correction at
Installation distance [L_t1 ^C(I, i + 1)]) + (measurement t_TwoTo
Corrected distance between opposing stations after correction [L_t2 ^C(I, i
+1)])｝, Equation (5B): [ε (i, i + 1)]_t1 ^t2≡ ｛(Measure
Time t_TwoOf the true installation distance between opposing stations [L_t2 ^C
(I, i + 1)])-(at the time of measurement t₁True after correction in
Installation distance [L_t1 ^C(I, i + 1)])｝ /
(At the time of measurement₁Corrected distance between opposing stations after correction
[L_t1 ^C(I, i + 1)]). 3. A transmitting station for transmitting an optical pulse through a fault at the bottom of the water, a relay station for receiving the optical pulse and transmitting the light pulse to a next station, and receiving an optical pulse from the relay station. A measurement line is provided in which a receiving station at the final stage is disposed opposite to the receiving station at predetermined intervals, and a light beam for observation is transmitted from the transmitting station to the receiving station via the relay station. The pulse is branched, and the photoelectrically converted pulse train is transmitted to a ground station via a transmission cable. At the time of reference amount measurement τ ₁ , the photoelectric conversion pulse train is fetched, and the branch pulse between the opposed stations is set to 1 And a one-way pulse propagation time width ΔT between the opposing stations for each set.
Is obtained and added to obtain the propagation time T of the survey line as a reference propagation time. The reference propagation time T is compared with the propagation time T obtained at the measurement time τ ₂ after the reference amount measurement time τ ₁ , What is claimed is: 1. An optical distance measuring device comprising: a data processing device for identifying the presence or absence of a change in horizontal distortion in a water base from the presence or absence of the difference. The data processing device is configured to set the measured water temperature at the reference amount measurement time τ ₁ to an initial temperature t _As ° C, and to set the measured refractive index of water at the water temperature to an initial refractive index n _As. The propagation velocity of the light pulse obtained by substituting the initial refractive index n _As into the following equation 1 is defined as the initial propagation velocity v _As ,
The sum of the measured pulse propagation time width ΔT for each set between the stations is stored in the storage means as the initial propagation time T _As , and the measured refractive index at the measured water temperature t _n ° C at the measurement time τ ₂ after the measurement of the reference amount is measured. calculating the propagation velocity v _n of light pulses by substituting n _n the following arithmetic expression 1, it calculates the sum of the measured pulse propagation time width ΔT of said set each as measured propagation time T _n, after the reference measuring the measured propagation time T _n and the propagation velocity v _n of the measurement time tau _2, the propagation time T _Asn found by replacing the above initial propagation velocity v _as the following operation expression 2, when measured after the reference measuring tau ₂ is the measured propagation time T _n and the initial temperature t
Stored and held as a temperature compensated propagation time T _Asn in the initial propagation time T _As at _As ° C., by comparison with the reference amount initial propagation time of the measuring time tau ₁ T _As the temperature corrected the propagation time T _{As n,} An optical distance measuring apparatus characterized in that the presence or absence of horizontal distortion is identified based on the comparison result. Arithmetic formula 1: v = C ₀ / n, where n is the actually measured refractive index of water at the time of measuring τ ₁ and τ ₂ after measuring the reference amount, and C ₀ is the speed of light in vacuum ( 3 × 10 ⁸ m / s), and v represents the calculated initial propagation velocity of the light pulse in water at the time of measurement of the reference amount τ ₁ and the time of measurement τ ₂ after the measurement of the reference amount. Equation 2: T _Asn = (V _n · T _n ) / v _As , where v
_As early propagation speed of light pulses in water was measured in the reference measuring time tau _1, v _n is the propagation velocity in water of light pulses in the measurement time tau ₂ after the reference measuring time tau _1, T _n is The measured propagation time T ₂ at the measurement time τ ₂ , T _Asn is the propagation time obtained by temperature correction of the measured propagation time T _n at the measurement time τ _{2 to} the initial propagation time T _As at the initial temperature t _As ° C at the time of the reference amount measurement τ _1. Show. 4. An optical measuring system disposed in a direction of transmitting a laser beam from a transmitting station that transmits the optical pulse, for each station on the measurement line, and in the direction of transmitting the laser beam. By providing an optical measurement system in the opposite direction to the above, a round-trip optical measurement system is formed on the measurement line, and the pulse propagation time width data detected by the round-trip optical measurement system and each station The optical distance measuring device according to claim 1, wherein the detection data from the sensor provided in (1) is transmitted to the data processing device. 5. 5. The transmission line transmitting a light pulse for propagation of the path, a plurality of transmission lines composed of a sequence of a transmission station, a relay station, and a reception station positioned at the head of the path, Laying so that the leading transmitting station is located in parallel, the transmitting station of the above-mentioned survey line, and the leading transmitting station of each survey line each transmit a propagation light pulse branched from the propagation light pulse transmitted by the transmitting station of the above-mentioned survey line. Optically coupled so as to sequentially propagate to the top transmission station of the survey line, from the top transmission station of each measurement line to the receiving station via the relay station,
A light transmission pulse is transmitted, and a photoelectric conversion pulse train of an observation light pulse branched from the propagation light pulse branched from the head transmitting station, the relay station, and the reception station of each measurement line, and a sensor provided for each station 4. The optical distance measuring apparatus according to claim 1, wherein the detected data is transmitted to the data processing device. 6. A predetermined station on the survey line is a branch station for branching a propagation optical pulse transmitted from the transmitting station,
In a plurality of directions from the branch station, a plurality of branch measurement lines each consisting of a transmission station, a relay station, and a reception station positioned at the head are laid and branched, and the propagation light pulse is branched at the branch station. Light is transmitted from the head transmitting station of each branch path to the receiving station via the relay station, and an observation optical pulse branched from the propagation optical pulse from the head transmitting station, relay station, and receiving station of each branch path. 4. The optical system according to claim 1, wherein the photoelectric conversion pulse train and the detection data of a sensor provided at each station of each of the branch survey lines are transmitted to the data processing device. 5. Distance measuring device. 7. An observation station is laid at each position where a number of triangle vertices are formed on the water floor. The observation station transmits a light propagation pulse generated from the observation station to an observation station adjacent to the observation station. By transmitting light to half of the observation stations, and receiving light propagation pulses transmitted from the remaining half of the adjacent observation stations, the observation stations can communicate with each other. An optical distance measuring device optically coupled to the observation station, and transmitted between the observation station and each observation station adjacent to the observation station, the detection propagation time width data of the light propagation pulse received and received,
4. The optical distance measuring apparatus according to claim 1, wherein said detection data of a sensor provided at each observation station is transmitted to a data processing device. 8. The above-mentioned photoelectric conversion pulse train is transmitted to a ground station via a transmission cable, and a set of branch pulses from stations installed opposite to each other is set, and a pulse propagation time width ΔT for each set is set.
The optical distance measuring apparatus according to claim 1 or 3, wherein the number is counted by a plurality of clock pulses having different frequencies. 9. A transmitting station that transmits an optical pulse through a fault at the bottom of the water, a relay station that receives the optical pulse and transmits the optical pulse to a next station, and receives an optical pulse from the relay station. A survey line with the last receiving stations arranged at predetermined intervals is laid, and a transmission cable from a ground station equipped with a data processing device is connected to the transmitting station, relay station, and receiving station. the transmission cable interposed between each other, the distributed optical fiber thermometer which connects respective stations to each other and additionally provided respectively, the reference measuring time t ₁ and the surveying from each scheduled t ₁ after a predetermined time during measurement t ₂ At the time of measurement, one of the opposing stations is directed from one opposing station to the other opposing station, and one of the branched optical pulses Sw branched at the one opposing station is transmitted through the underwater optical path interposed between the opposing stations. And the other branch light pulse Sc Transmitted via the optical fiber optical path of a distributed optical fiber thermometer connecting the stations, and receiving the branch light pulse Sc and the reference light pulse Sp by the first component detection unit of the measurement and calculation device installed in the other counter station. Then, the first component signal indicating the detected phase difference between the pulses Sc and Sp, the branch light pulse Sw and the reference light pulse Sp are received and detected by the second component detection unit of the measurement and calculation device. transmitted to the ground station via respective transmission cables the reference amount detection signal of the measuring time t ₁ and a measurement time t ₂ indicating the phase difference between the second component signal indicating a phase difference between the pulses Sw and Sp, ground at the station, compared with the detection signal at the time of measurement in the reference measuring time t _1, a phase difference between the detection signal at the time of measurement in the measurement time t _2, on the basis of the comparison result, between the opposed stations constituting survey line Temperature and the remainder An optical distance measuring apparatus for identifying the presence or absence of a fault, the presence or absence of the expansion and contraction of a fault, and the presence or absence of crustal deformation irrespective of a difference in water temperature between the opposite stations.