JPH02218982A - Ultrasonic apparatus for measuring speed of ship - Google Patents

Abstract

PURPOSE:To enable prevention of lowering of functions of a system apparatus to which a value of the speed of a ship is supplied, by displaying the ship speed determined from the number of rotations of a propeller shaft when there is a difference of a prescribed value or above between a ground speed determined by an ultrasonic wave and said speed. CONSTITUTION:A transducer 16 transmits an ultrasonic pulse downward and supplies a received reflected wave to a receiver 18. A frequency counter 20 counts a specified depth and the deviation of the Doppler frequency of the reflected wave from the seabed and supplies a counted value to an arithmetic unit A22. The arithmetic unit 22 calculates a log speed VW/ground speed VB of a ship and supplies the same to an arithmetic unit B30, a comparator 32 and a switch 36. Besides, a rotation number data signal of an engine/propeller shaft is supplied to the arithmetic unit 30 and related therein to the relationship of the speed VW/VB. The comparator 32 compares the speed VW/VB with a ship speed V and supplies the switch 36 with a switching signal for outputting the ship speed V (VW/VB) in the case when a difference between these speeds is a prescribed value or above (below). Based on this switching signal, the switch 36 supplies a display unit 40 with a signal showing each speed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ultrasonic ship speed measuring device, and more specifically, when measuring ship speed by transmitting and receiving ultrasonic pulses, In addition to measuring the Doppler frequency deviation from the signal,
Calculate a first speed relative to the ground and/or water (hereinafter referred to as ship speed as necessary), further calculate a second ship speed from the engine or shaft rotation speed of the ship,
After that, when bubble formation occurs and the first ship speed value decreases, the occurrence state of bubble formation is displayed, and the second
An ultrasonic ship that displays the ship speed as a reference value and sends it as a signal, thereby effectively preventing functional deterioration in the operation of system equipment, such as radar, to which the ship speed value signal is provided. This invention relates to a speed measuring device.

[Prior Art] Conventionally, in an ultrasonic ship speed measuring device installed on a ship, an ultrasonic pulse is emitted into the sea from a transmitter via a transducer installed on the bottom of the ship, and then the ultrasonic pulse is emitted into the sea via a transducer installed on the bottom of the ship. Ultrasonic pulses reflected from underwater targets are received by the transducer, and ship speed is calculated from the Doppler frequency deviation of the signal obtained here. Furthermore, the obtained ship speed value is integrated to calculate the cruising distance, which is also displayed.

[Problem to be Solved by the Invention] However, this type of ultrasonic ship speed measuring device has the disadvantage that, like other ultrasonic devices, it is susceptible to the effects of air bubbles when transmitting and receiving ultrasonic pulses. There is. When installing a transducer on the bottom of a ship, it is difficult to find the optimal position that will not be affected by air bubbles, and even if the optimal position is determined, the transducer cannot be installed in the optimal position because of its large shape. There are cases. In such a case, the transmitted and received ultrasonic pulses are affected by the bubbles and cannot indicate the correct value of the ship's speed. In particular, in the Hiraki area, even if there are no obvious problems, foam formation that sometimes occurs due to cargo conditions, sea conditions, etc. can lead to an extreme decrease in ship speed compared to the actual value. Such ship speed values may be determined by other system equipment, e.g.
Ship speed information is sent to the N5S, radar, data logger, etc. In such a case, the operating functions of the system equipment mentioned above will not be maintained properly, and therefore, cooperation with these system equipment will not be possible. This will significantly hinder the operation of ships based on the above regulations.

The present invention has been made in view of the above points, and displays a second ship speed calculated from a signal indicating the engine rotation speed or shaft rotation speed as a reference value together with the normally obtained first ship speed, And by sending it to the system equipment,
It is an object of the present invention to provide an ultrasonic ship speed measurement device that can minimize the adverse effects of other system equipment that operates based on the reference value.

[Means for Solving the Problems] In order to achieve the above object, an ultrasonic ship speed measuring device including a transmitter and a receiver that transmit and receive ultrasonic pulses via a transducer according to the present invention is provided. A first method that measures a Doppler frequency deviation from the ultrasonic pulses generated by the vessel and calculates a first velocity of the vessel relative to the ground and/or water.
an input circuit into which a signal indicating the rotational speed from a ship's engine tachometer or shaft tachometer is input;
a second calculation means for calculating a second ship speed from a signal via the input circuit; a comparison means for comparing the first speed with respect to the ground and/or water and the second ship speed; When the first speed relative to the ground and/or water has a difference of more than a predetermined value compared to the second speed,
Alternatively, the apparatus is characterized in that it is configured to include a display means for displaying a second velocity in place of the first velocity relative to the water.

[Function] In the ultrasonic ship speed measuring device of the present invention configured as described above, in addition to the normally obtained first ship speed, the second ship speed calculated based on the engine rotation speed or the shaft rotation speed can be measured. is displayed as a reference value and sent out as an output signal, and as a result, the influence on other system equipment is suppressed to a minimum.

[Example] Hereinafter, an example of the ultrasonic ship speed measuring device according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows the configuration of an embodiment of the present invention. This example includes a transmitter 12 that transmits ultrasonic pulses, a transmission/reception switching circuit 14, and an ultrasonic pulse transmission/transmission device 16, and further includes a receiver 18, a frequency counter 20, and a first It includes a computing unit (A) 22 which is a computing means, and an input circuit 26 into which a signal indicating the engine rotational speed or the shaft rotational speed is input.

Furthermore, it is composed of a keyboard 2ill, a computing unit (B) 30 which is a second computing means, a comparator 32, a switch 36 and a display 40.

Next, the measuring device of the present invention having the above configuration will be explained in detail with reference to FIGS. 2 and 3.

First, an ultrasonic pulse generated by the transmitter 12 is supplied to an ultrasonic pulse transducer 16 via a transmission/reception switching circuit 14 . The transducer 16 emits ultrasonic pulses obliquely downward in the bow direction, receives the reflected waves, converts the received reflected waves into electrical signals, and supplies the electrical signals to the receiver 18 . Then, the frequency counter 20 counts the Doppler frequency deviation of the reflected waves at the specified depth and the Doppler frequency deviation of the seabed reflected waves, and the obtained data signal is sent to the computing unit (A) 22. supply In this computing unit (A) 22,
Based on the Doppler frequency deviation data, a signal that calculates the water speed Vw of the ship with respect to the moving object in the water and the ground speed VB of the ship with respect to the seabed is supplied to the calculator (B) 30, the comparator 32, and the switch 36. do. In addition, the arithmetic unit (A
) 22, calculate the standard deviation indicating the dispersion of the data of the water speed VW and the ground speed V8, and calculate the derived signals as the standard deviation σ of the water speed V, and the ground speed V, respectively.
The standard deviation σ of B is supplied to the arithmetic unit (B) 30 and the comparator 32.

On the other hand, a rotational speed data signal obtained from a tachometer or the like of the engine or shaft (not shown) is supplied to the arithmetic unit (B) 30 via the input circuit 26.

The arithmetic unit (B) 30 associates the input water speed V1w and ground speed V8 with the rotational speed data signal. Figure 2 shows these relationships. The data that should serve as the basic relationship is obtained during speed tests. The speed test is usually performed four times at different rotational speeds, and in FIG. 2, R1, R2, R3, and R4 correspond to this. The ship speeds V1, V2, V3, and V4 at this time are the water speed VW or the ground speed VB input from the computing unit (A) 22. These ship speeds can also be input from the keyboard 2B as values announced by the shipyard. Arithmetic unit (B) 30
Then, based on these values, an approximate expression of a cubic curve a representing the relationship between the number of revolutions and the ship speed is calculated by the least squares method, and is stored in an internally provided RAM or the like.

t=AR3+BR2+CR+D...(1)
Here, V is the ship's speed, R is the rotation speed, and A, B, and C.

D represents the calculated coefficient.

During normal voyages, depending on the wind, current, cargo condition, etc.
The ship speed does not match the above-mentioned approximation formula (1), and as shown in FIG. 3, it is considered that it varies with a width of ±α with respect to the curve a. In FIG. 3, the curve S represents the upper limit of the variation, and the curve C represents the lower limit of the variation. In order to eliminate this variation, the computing unit (B) 30 corrects approximate expression (1) from the rotational speed input at regular intervals and the water speed VW or ground speed Vn.

The problem here is the water velocity V. or ground speed v,
The accuracy is l. Normally, these speeds VW or VIl have an accuracy of ±1% or less, but when air bubbles flow into the transducer surface, the frequency spectrum expands, and the calculated boat speed value becomes - true for boat fishing. The value will be smaller than the value.

It is well known that in extreme cases, the value will be less than half of the true value. The standard deviation σ of the water velocity VW can be used as a measure of the bubble-filled state. That is, when bubble formation occurs, σ becomes a large value. Therefore, the arithmetic unit (B) 30 can prevent abnormal data from being taken in by not performing the calculation of the approximation formula (1) when the value of σ is greater than a certain value. I can do it.

On the other hand, the comparator 32 compares the water speed VW or the ground speed V input from the calculator (A) 22 with the calculator (B) 30.
, and if the difference between them is less than a predetermined value, a switching signal for outputting the water speed Vw or the ground speed V is supplied to the switch 36. Furthermore, a switching signal for outputting the boat speed V is supplied to the switching device 36 even when the boat speed is equal to or higher than a predetermined value. The switch 36 operates to supply a signal indicating the water speed VW or the ground speed Vll to the display 40, or a signal indicating the ship speed V, based on the switching signal.

In addition, when a signal indicating the ship speed V is supplied, it is indicated that the ship speed V is calculated and displayed based on the rotation speed of the engine tachometer or shaft tachometer, since it is affected by air bubbles. information signals are also supplied to the display 40.

If such rotational speed and true ship speed are obtained in advance, the data is input to the calculator (B) via the keyboard 28.
It is also possible to input it to 30.

[Effects of the Invention] As described above, according to the ultrasonic ship speed measuring device of the present invention,
When transmitting and receiving ultrasonic pulses, the Doppler frequency deviation is measured from the received signal, a first speed relative to the ground and/or water is calculated, and a second speed is calculated from the ship's engine or shaft rotation speed. The ship speed is calculated, and after that, when foam formation occurs and the first ship speed value decreases, the state of occurrence of foam formation is displayed, and the second ship speed is displayed as a reference value. and a system device that provides a value of ship speed by transmitting it as a signal,
For example, it has the effect of preventing functional deterioration of NN5S routers, data loggers, etc.

[Brief explanation of the drawing]

Fig. 1 is a circuit block diagram showing an embodiment of the ship speed measurement and display device according to the present invention, Fig. 2 is an explanatory diagram showing the relationship between the rotation speed and the ship speed, and Fig. 3 is an explanatory diagram showing the relationship between the rotation speed and the ship speed. FIG. 3 is an explanatory diagram showing the relationship between upper and lower limits. 12... Transmitter 14... Transmission/reception switching circuit 16... Transducer/receiver 18... Receiver 2
0...Frequency counter 26...Input circuit 30...Arithmetic unit (B) 36...Switcher 22...Arithmetic unit (A) 28...Keyboard 32...Comparator 40. ··display

Claims (1)

[Claims] (1) In an ultrasonic ship speed measurement device that includes a transmitter and a receiver that transmit and receive ultrasonic pulses via a transducer, it measures the Doppler frequency deviation from the received ultrasonic pulses and measures the Ground and/or water first
a first calculation means for calculating the speed of the ship; an input circuit into which a signal indicating the rotational speed from the engine tachometer or the shaft tachometer of the ship is input; and a second calculation means for calculating the speed of the ship from the signal via the input circuit. a second calculation means for calculating; a comparison means for comparing the first speed with respect to the ground and/or water and a second ship speed; display means for displaying a second speed in place of the first speed relative to the ground and/or water when the difference is greater than a predetermined value compared to the first speed relative to the ground and/or water; An ultrasonic ship speed measurement device comprising: