JPH0625666B2 - Sounding device with seafloor reference point - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sounding device using a seafloor reference point.

[Prior art] For example, for seafloor topography surveys of marine civil engineering works (bridges, breakwaters, offshore artificial islands, etc.), seafloor excavation surface shape surveys, performance surveys, rubble mound average shape surveys, etc. The method of measuring with an ultrasonic sounder from a ship on the sea is generally used. In addition, a technique of suspending a traveling robot or a pedestal on the seabed and measuring with an ultrasonic sounding machine mounted on these is partially used.

[Problems to be Solved by the Invention] In the above-mentioned conventional method, the former measures the bathymetric position from the coast by optical surveying, radio wave surveying, etc., corrects the shaking of the vessel and adds it to the bathymetric data to determine the depth to the seabed. To measure the
It was difficult to keep the accuracy within plus or minus several tens of cm.

The latter is a so-called SBL type transponder method that uses a plurality of transponders installed at the bottom of the sounding position to measure distance using ultrasonic waves. There was an error of.

In addition, the full-text specification of Japanese Utility Model Laid-Open No. 60-148974 makes it easy to measure water depth without a correction even if the speed of sound changes, by using a surveying instrument on the seabed and using an underwater working machine linked to it. There is disclosed a leveling device for an underwater working machine which can be carried out. However, it is not possible to obtain the plane coordinates and depth of the sea floor (specifically, contour maps, depth distribution maps and cross-sectional views).

SUMMARY OF THE INVENTION It is an object of the present invention to solve these problems and provide a bathymetry device with a seafloor reference point that obtains plane coordinates and depth of the seafloor with high accuracy.

[Principle] As a result of various researches on the present invention, a high-precision water depth gauge is installed at a reference point where the depth has been accurately measured in advance on the seabed, while a similar high-precision water depth gauge is installed on a platform suspended from a support ship. By adding the depth of the reference point to the differential pressure of these two high-precision water depth gauges, the suspension depth of the gantry is calculated, and the depth of the sea bottom can be measured with high accuracy based on the suspension depth. I found it.

That is, the water depth D of the water depth meter is D = (P-PA) × (1 / d) × (1 / g) where P: water depth gauge PA: atmospheric pressure d: seawater density g: gravity acceleration The density d varies depending on the temperature and salinity of seawater, and it is difficult to accurately determine the depth due to the gradient change from the sea surface to the sea bottom.

On the other hand, as shown in FIG. 1, a base (or a traveling robot) suspended from a reference point P and a support ship (not shown).
Depth of the gantry T is D0 + (DT-DP), where depth gauges MP and MT are provided at T, pressures of these depth gauges are PP and PT, water depths are DP and DT, and depth of the depth gauge MP is D0. = D0 + {(PT-PA) * (1 / d) * (1 / g)}-{(PP / -PA) * (1 / d ') * (1 / g)}, and DP and DT When the difference is small, d≈d ′, and D0 + (DT−DP) = D0 + (PT−PP) × (1 / d) × (1 / g), the atmospheric pressure is offset, and both depth gauges The depth of the gantry can be accurately determined by the differential pressure between MP and MT, and therefore the depth of the sea floor can be accurately determined.

In addition, a transponder is installed on the gantry, and the transponder is installed at a plurality of locations on the seabed in advance.Ultrasonic signals are transmitted to transponders with known installation coordinates, and the plane coordinates of the gantry can be accurately determined from the response time. I found it. The present invention has been made based on such a principle.

[Means for Solving the Problems] According to the present invention, a first transponder, a first water depth meter, and an inclinometer, which are fixedly installed on a cradle suspended from a support ship,
A gyro compass and an ultrasonic sonar movably provided on the gantry, and a second responsive to a signal from the first transponder, the ultrasonic sonar being provided at a plurality of locations on the seabed whose installation coordinates are known.
A transponder, a second depth gauge installed at a reference point on the seabed, and a processing device provided on the support vessel,
The underwater position measuring device connected to the first transponder, the gyro indicator connected to the gyro compass and the inclinometer, the sonar control device connected to the ultrasonic sonar, and the first to the processing device. A computer to which the water depth gauge is connected, the underwater position measuring device, a sonar control device and a data recording device having a display and a printer connected to the computer, and a display for processing a floppy disk of the data recording device, An output computer that includes a printer and a plotter and outputs a contour map, a depth distribution map, a sectional view, and the like is provided.

The water depth gauge is preferably a tide gauge equipped with a crystal oscillation type pressure sensor, for example.

[Operation] In the sounding device with the seafloor reference point configured as described above, an ultrasonic signal is transmitted from the first transponder of the gantry to the second transponder, and the plane position of the gantry is determined from its response time.

Then, the depth of the gantry is obtained from the pressure difference between the first and second depth gauges.

Then, the azimuth angle, trim angle, and heel angle of the mount are corrected by the tilt angle and the gyro compass, and the position coordinates of the ultrasonic toner are three-dimensionally obtained.

Then, the ultrasonic sonar is moved to scan the seabed to measure the distance to the seabed, and the plane coordinate and depth of the seabed are obtained from the distance measurement data and the position coordinates by the position measuring device, for example, an isobath map, Obtain a processing device for depth distribution maps, cross-sectional maps, etc.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 2, from the support vessel 1, a platform indicated by reference numeral 10 is suspended on the seabed, and a plurality of (three in the illustrated example) second transponders are provided around the platform 10. A certain slave station transponder 2 is provided, and at the seafloor reference point P, a second tide gauge 3 having a crystal oscillation type pressure sensor which is a second water depth gauge is provided.

In FIG. 3, parallel rails 12, 12 are provided on the legs 11, 11 of the gantry 10. A master station transponder 13 that is a first transponder and a first tide gauge 14 similar to the second tide gauge 3 that is a first water gauge are provided at one end of the rail, in proximity to the master station transponder 13. A gyro compass 15 and an inclinometer 16 are provided near one of the legs 11. A traveler 17 is provided on the rails 12, 12 so as to be movable in the longitudinal direction by a hydraulic drive device 18, and a rotary encoder 19 (FIG. 4) for measuring the amount of movement is provided. Reference numerals 11a and 11a in the figure are balance weights.

A beam 19a is fixedly mounted on the traveler 17 orthogonally to the rails 12, 12, and ultrasonic sonars 20, 20 are provided below the ends of the beam 19a, respectively.

In FIG. 4, the support ship 1 is provided with a processing device indicated by the whole symbol PU, and the processing device PU has a pedestal 10
Main station transponder 13, an underwater position measuring device 23 to which a water temperature gauge 21 is connected, a position display device 24, a gyro compass 15 and a gyro indicator 2 to which an inclinometer 16 is connected.
5 and the sonar control device 2 to which the ultrasonic sonar 20 is connected
6, a sonar color indicator 27, a handheld computer 28 to which the first tide gauge 14 is connected, a wireless modem 2
9, a hydraulic control device 18, a motor control panel 30 to which the rotary encoder 19 is connected, and a controller 31 are provided. The wireless modem 29 communicates with a handheld computer 32 provided in the strong current buoy 4 and connected to the second tide gauge 3 via a wireless modem 33.

Further, the underwater position measuring device 23, the sonar control device 26, the handheld computer 28 and the controller 31 are
An output personal computer 38 which is connected to a data recording device 36 having a display 34 and a printer 35 and processes the floppy disk 37 is provided. The personal computer 38 includes a display 39, a printer 40 and a plotter 41. It is connected.

At the time of measurement, an ultrasonic signal is oscillated from the master station transponder 13 to the slave station transponder 2 which is installed at three locations on the seabed in advance and whose installation coordinates are known, and the position of the master station transponder 13 is determined by the underwater position measuring device 23 from the response time. taking measurement. At this time, theoretically accurate data cannot be obtained for the data in the water depth direction if the difference between the installation water depths of the gantry 10 and the slave station transponder is small.

On the other hand, from the pressure difference between the first tide gauge 14 and the second tide gauge 3, an accurate depth is calculated as shown in the principle, and the plane coordinates (X, Y) by the transponders 2 and 13 described above are calculated. Input as rough data to reduce the measurement error of plane coordinates.

The position (X, Y, Z coordinates) of the gantry 10 thus obtained is used as a reference, and the data of the azimuth angle α, the trim angle β and the heel angle γ of the gyro compass 15 and the inclinometer 16 are used in FIGS. As shown in the figure, the position coordinates of the ultrasonic sonars 20, 20 depending on the posture of the gantry 10 are three-dimensionally corrected.

For the measurement, the ultrasonic sonar 20 measures the scanning angle by, for example, a mechanical scanning method with a rotary encoder for scanning angle (not shown), and the movement amount of the gantry 10 in the longitudinal direction is measured by the rotary encoder 19, and the scanning of the scanning beam B The distance measurement data corresponding to the angle θ is fetched, and the sonar control device 26 measures the distance in a plane, and the plane coordinates and depth of the seabed scanned from the distance measurement data and the three-dimensional coordinates of the ultrasonic sonar 20 are calculated. In addition, the diameter of the scanning beam B is as small as 30 cm with respect to the beam diameter of 1 m when scanning 60 m below the sea surface by the conventional ultrasonic sonar, and the uneven shape can be accurately measured.

The data stored in the floppy disk 37 of the plane coordinates and depth of the sea bottom obtained by the ultrasonic sonar 20 as described above is processed by the personal computer 38, and a predetermined contour map C1 (Fig. 8) and depth distribution map C2 ( FIG. 9), a sectional view in which the horizontal axis represents one-directional coordinates and the vertical axis represents depth.
Figure) is created.

In this embodiment, as shown in FIG. 9, X = 10 m divided by 40 × 49 mesh (mesh size 25 cm), Y =
Although the depth distribution map C2 of 12.25 m is output, it is divided into a maximum of 100 × 100 mesh per installation point, and the depth measurement range of X = 14.5 m, Y = 20 m is added to the position accuracy plus / minus. Within 40 cm, within ± 10 cm of sounding accuracy, and within 5 mm of depth variation,
It can be output in a bathymetry time of 10 minutes. The ninth
The number of vertical lines in the figure represents the depth.

[Advantages of the Invention] Since the present invention is configured as described above, it has the effects described below.

(A) By scanning a beam from an ultrasonic sonar suspended on the seabed, the beam diameter can be made much smaller than in the prior art, and the uneven shape can be accurately measured. Further, the plane coordinates (X, Y coordinates) of the gantry can be accurately measured by the parent and child transponders without being affected by the tidal current or the water temperature gradient.

(B) Further, the depth (Z coordinate) of the gantry can be accurately measured without being affected by water temperature, salinity concentration, atmospheric pressure, tide level change, etc. by the pressure difference between the two tide gauges.

(C) Therefore, it is possible to obtain the plane coordinates and the depth of the sea bottom with high accuracy, and obtain a contour map, a depth distribution map, a sectional view, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a drawing for explaining the principle based on the present invention, FIG. 2 is a perspective view showing the outline of an apparatus for carrying out the present invention, and FIG. 3 shows the details of the gantry shown in FIG. An explanatory perspective view, FIG. 4 is an overall configuration diagram of the device, FIGS. 5, 6, and 7 are azimuth angles of the mount,
The side view showing the correction state of the trim angle and the heel angle, No. 8
FIG. 9, FIG. 9 and FIG. 10 are a contour map, a depth distribution map and a sectional view showing the measurement results. P: seabed reference point, PU: processing device, 1 ... support ship,
2 …… Slave station transponder, 3 …… Second tide gauge, 10
…… Stand, 13 …… Master station transponder, 14 …… 1st
Tide gauge, 15 gyro compass, 16 inclinometer, 18 hydraulic drive, 19 rotary encoder, 20 ultrasonic sonar, 23 underwater position measuring device, 38 output personal Computer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaaki Ueda 1-2-7 Moto-Akasaka, Minato-ku, Tokyo Within Kashima Construction Co., Ltd. Kashima Construction Co., Ltd. Osaka Branch (72) Inventor Kuniyoshi Nakagome 1-3-15 Awaza, Nishi-ku, Osaka City, Osaka Prefecture Kashima Construction Co., Ltd. Osaka Branch (56) References: Actual Development Sho 60-148974 (JP, U)

Claims (1)

[Claims] 1. A first transponder, a first water depth meter, an inclinometer, a gyro compass, and an ultrasonic sonar movably provided on the pedestal suspended from a support ship, and installation coordinates. , A second transponder provided at a plurality of known locations on the seabed for responding to signals from the first transponder, a second water depth gauge installed at a reference point on the seabed, and provided on the support vessel. A sonar control in which the underwater position measuring device connected to the first transponder, the gyro indicator connected to the gyro compass and the inclinometer, and the ultrasonic sonar are connected to the processing device. Device, a computer to which the first depth gauge is connected, the underwater position measuring device, a sonar controller and a display and printer to which the computer is connected A seafloor reference point provided with a data recording device and an output computer which is equipped with a display for processing a floppy disk of the data recording device, a printer and a plotter, and outputs an isobogram, a depth distribution map, a sectional view, etc. Sounding device.