JP2520734B2 - Ultrasonic power flow measuring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention automatically sets the depth of a tidal current measurement layer to be always constant with respect to the seabed, and complicates the setting operation of the tidal current measurement layer, and The present invention relates to an ultrasonic power flow measuring device that eliminates inaccuracy and impossibility.

(Prior Art and Problems to be Solved) In preparing a distribution map of the velocity and direction of a tidal current in the sea, a tidal current measuring device based on the following principle using ultrasonic waves is used.

For example, as shown in FIGS. 1 (a) and (b) and FIG. 2, this device is controlled by a transmission control signal P ₁ from a control unit (1) by a transmission drive signal P ₂ from a transmission unit (2). Four ultrasonic beams S _a , S _b , S _c , S _d in the front-back and left-right directions of the ship which were simultaneously launched in the oblique direction of the seabed B from the transducers (3a) (3b) provided in To do. And Figure 3 (a) from the plankton floating in the sea based on these
Of the reflected waves R _pa , R _pb , R _pc , R _pd (only R _pa is shown in the figure) and the reflected waves R _Ba , R _Bb , R from the seabed B in FIG. 3 (a).
_It receives _Bc and R _Bd (only R _Ba is shown in the figure) and converts them into electrical signals. After that, the receiving amplifier (4a) in Fig. 2
After amplification to the required level by (4b), (4c), and (4d), the slice circuit (5a) (5b) is utilized by utilizing the fact that the level of the seafloor reflection signal is larger than the level of the reflection signal from plankton, for example. ) (5c) and (5d) detect submarine reflection signals R _Ba , R _Bb , R _Bc , and R _Bd above the threshold level shown by the broken line in FIG. 3 (d), and thereby the gate signal generation circuit (6a) By controlling (6b), (6c) and (6d), the gate signals g _1a , g _1b , g _1c and g _1d shown in FIG. 3 (c) are produced. And by these, the gate circuit for submarine reflection signal acquisition (7a)
(7b) (7c) (7d) is opened for a certain period of time, and the seabed reflection signals R _Ba , R _Bb , R _Bc , and R _Bd of a certain time width are extracted for each transmission, and the arithmetic circuit (8) is extracted. Add.

On the other hand, the seabed reflection signals R _Ba , R _Bb , R _Bc , and R _Bd obtained from the slice circuits (5a) (5b) (5c) (5d) are compared by a comparison circuit (9), and the deepest water among them is extracted. To detect shallow ocean bottom reflection signals. Based on this, the gate is controlled manually by the output signal of the manual depth setting circuit (10) that sets the time from the transmission of the water corresponding to the depth of the tidal current measurement layer to the return of the reflected wave from the tidal current measurement layer. The signal generation circuit (11) produces the gate signal g ₂ of FIG. 3 (b). And by these, the gate circuits (12a) (12b) (12c) (12d) for acquisition of reflected signals such as plankton are opened for a certain period of time, and the plankton at a set depth shallower than the depth of the seabed is transmitted for each transmission. Operation circuit by extracting signals R _Pa , R _Pb , R _Pc , and R _Pd of constant time width based on the reflection of
To enter.

Then, the arithmetic circuit (8) is included in the seabed reflection signals R _Ba , R _Bb , R _Bc , R _Bd input here and the reflection signals R _Pa , R _Pb , R _Pc , R _Pd from plankton or the like. Utilizing the fact that the frequency component changes due to the Doppler effect, reflected signals R _Pa , R _Pb , R _Pc such as plankton are transmitted every time the transmission is performed, that is, every time the transmission control signal P ₁ is added from the control unit (1). , R _Pd to calculate the ship speed V _Wa , V _Wb , V _Wc , V _Wd and calculate the seabed reflection signal R _Ba , R _Bb , R
Calculate ship speeds V _Ea , V _Eb , V _Ec , and V _Ed from _Bc and R _Bd , respectively. Further, the difference between the watercraft speed and the groundcraft speed in the front-rear direction and the left-right direction is calculated, and then converted into a vector, and the speed and direction of the tidal current are vectorically calculated for each transmission,
The display device (13) is adapted to display.

By the way, when measuring the tidal current in the tidal current measurement layer with a constant water depth as shown by the broken line a in Fig. 1 (c), when the water depth of the seabed B becomes shallow, the reflected signal from the plankton etc. And the reflected signals from the seabed overlap or are extremely close. Therefore, it is unavoidable that the measurement cannot be performed or the measurement result is inaccurate. Therefore, in such a case, it is necessary to change the setting of the water depth of the tidal current measurement layer as shown by the broken line b in FIG. 1 (c), but in the conventional device, this setting should be made manually as described above. Therefore, the setting operation becomes extremely troublesome especially when the undulations of the seabed change drastically. Therefore, the conventional device has a problem that must be solved in terms of measurement operation and maintenance of measurement accuracy.

(Object of the Invention) The present invention is intended to solve the problems of the conventional device as described above by automatically setting the tidal current measuring layer having a constant water depth shallower than the seabed. is there.

(Means of the present invention for solving the problem) In the present invention, the water depth of the seabed is measured at each transmission time, and the water depth of the tidal current measurement layer that is shallower than the seabed depth at that time by a certain distance is calculated from this. By controlling the gate circuit, it automatically follows the changes in the water depth of the seabed, so that the reflected signal from the plankton at a depth shallower than the seabed can be obtained. It is designed to prevent bothersomeness and overlap of the reflected signal from the seabed and the plankton. Next, the present invention will be described with reference to examples.

FIG. 4 is a block circuit diagram of an embodiment of the present invention.
(The same reference numerals as those of the conventional device shown in FIG. 2 indicate the same parts.) In the figure, (1) is a control unit, (2) is a transmission unit,
(3a) and (3b) are front-rear and left-right transducers (4a)
(4b) (4c) (4d) are receiving amplifiers, (5a) (5b) (5c
(5d) is a slicing circuit, (6a) (6b) (6c (6d) is a gate signal generating circuit, (7a) (7b) (7c) (7d) is a submarine reflection signal acquisition gate circuit, and (8) is an operation Circuit, (12a) (1
2b) (12c) ((12d) is a gate circuit for acquiring a reflected signal from plankton, etc., (9) is a comparison circuit, (13) is a display circuit, and the above circuit configuration is the conventional device of FIG. Is the same as.

The circuit denoted by reference numeral (14) is an automatic water depth setting circuit for the tidal current measuring layer provided for carrying out the present invention, and is formed of the following parts. (15) is an arithmetic circuit, (16) is a water depth setting circuit, and (17) is a gate signal generating circuit. Arithmetic circuit (1
5) is a transmission control signal P ₁ from the control unit (1) and the ultrasonic beams S _a , S _b , S _c , S _d obtained by the comparison circuit (9) as shown in FIG. Submarine reflection signals based on R _Ba , R _Bb ,
The seafloor reflection signal of the shallowest water depth among R _Bc and R _Bd , such as R _Ba
Then, the time τ ₁ from transmission to reception is calculated, that is, the time τ ₁ corresponding to the depth of the seabed shown in FIG. 5 (b) is calculated,
Further depth setting circuit (16) required for power flow measuring layer depth to 1 time corresponding to the seabed depth at the measurement start time based on the designation from, i.e. a fixed time tau ₂ from the seabed depth shown in FIG. 5 (e) Only for a short time, τ ₃ is calculated and stored. When the next transmission control signal P ₁ enters from the control unit at the time of transmitting, by the time tau ₃ after the gate signal generating circuit (17), making the gate signal g ₂ of a predetermined time width shown in FIG. 5 (d) , The gate circuits (12a) (12b) (12c) (12d) for acquiring the reflection signal from the plankton etc. open the gate for a fixed time width by the gate signal g ₂ to obtain the reception amplifier (4a).
From the reflection signals obtained through (4b), (4c), and (4d), as shown in FIG. 5 (e), the reflection signal R _Pa from a plankton or the like at a constant depth H from the seabed reflection signal R _{Ba at a} constant distance H. , R _Pb , R _Pc , R _Pd are obtained (only R _pa is shown in the figure) and added to the arithmetic circuit (8).

That is, according to the present invention, it is possible to automatically obtain a reflection signal from a plankton or the like at a constant water depth shallower than the seabed, regardless of the fluctuation of the water depth of the seabed, thereby eliminating the drawbacks of the conventional device.

The above circuit may be provided with a manual setting circuit similar to the conventional one so that either automatic or manual can be selected.

(Effects of the Invention) As described above, according to the present invention, the tidal current measurement layer can be automatically set to a constant depth shallower than the seabed based on the depth information. Therefore, the inconvenience associated with the manual setting operation as in the conventional device, and the drawbacks such as the measurement error and the measurement failure due to the overlap between the reflection signal from the plankton and the seabed reflection signal are eliminated, and the present invention is particularly suitable for the seabed. It has a great effect on the tidal current measurement on the rugged sea floor.

[Brief description of drawings]

1, 2 and 3 are explanatory views of a conventional device, and FIG.
FIG. 5 and FIG. 5 are explanatory views of an embodiment of the present invention.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location G01S 15/60 8907-2F G01S 7/52 J

Claims (1)

(57) [Claims] 1. A reflection signal from a plankton or the like at a required water depth set by a gate circuit from a reflection signal based on an ultrasonic beam emitted obliquely to the front and rear and left and right directions and a plankton at a required water depth. In the ultrasonic power flow measuring device that extracts the signals and calculates and displays the speed and direction of the tidal current by adding them to the arithmetic circuit, a circuit that measures the depth of the seabed at the time of transmitting the ultrasonic beam, and from this seabed depth signal A circuit for obtaining a shallow depth signal at a desired fixed distance, and a reflection signal from a plankton at a depth shallower than the seabed depth from the reflected signals of the plankton etc. controlled by this depth signal at the time of the next transmission And a circuit for extracting the ultrasonic wave.