JP2002370694A - Wave forecast information using method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further accurately make a course plan by measuring an in-wave speed reduction characteristic. SOLUTION: A ship speed s made to correspond to the wave height and the wave direction is determined on the basis of a ship position and the time obtained from a GPS receiver, wave forecast information, and a log speed. The ship speed s is also made to correspond to a propeller rotating speed n of a ship propelling engine, and information on the in-wave speed reduction characteristic is gathered and learnt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for deriving the amount of deceleration of a ship in waves or the speed of a ship decelerated with waves. The present invention particularly relates to a method for performing the derivation using wave forecast information.

[0002]

2. Description of the Related Art In operating a ship, it is desirable to formulate a route plan so that navigation can be made in a water area as calm as possible. This is because sailing in a calm water area, i.e., a water area in which the ship shakes little, enables safe navigation, shortens the time required to reach the destination, and suppresses fuel consumption. In other words, the speed of a ship generally decreases during a wave, so that the time required for navigation increases and the fuel consumption increases. Further, in order to prevent the hull and the load from being damaged due to the waves, the rotation speed of the marine vessel propulsion engine may be intentionally reduced or the engine may be stopped. In order to prevent various losses due to waves, including delays in arrival and waste of fuel for these reasons,
The shortest route in consideration of weather conditions (Note: The shortest route is not always the shortest route for the reasons described above)
The plan was to take measures.

[0003] When making a route plan in consideration of the weather, for example, the following equation is used.

V = VCALM−ΔV VCALM = a−bn ² ΔV = A {1−exp (−Bh ^C )} exp (−D}
^E ) + F｝ where V: ship speed in waves (knots) VCALM: ship speed in calm waters (knots) ΔV: amount of deceleration by waves (knots) n: propeller speed of ship propulsion engine (rpm) h: Significant wave height (m) ψ: Angle of dominant wave direction to ship course (rad) a, b: Ship-dependent constants A to F: Ship-specific constants empirically determined 1 knot = 1 nautical mile (1852 m) / 1 Time = 0.514
4 m / sec 1 rpm = number of revolutions per minute is used. This equation is an equation showing the deceleration state of the ship due to the waves, that is, a relational equation giving the deceleration characteristics in the waves.

[0004]

In order to accurately derive the deceleration amount ΔV and the boat speed V according to the above equations, the constants a,
b, AF must be accurate. Since each constant should theoretically take a different value for each ship, precise determination of each constant requires detailed theoretical calculations and actual measurements for each ship. However, in reality, such an operation is difficult or impossible to perform, so that it is usually determined according to the type and type of ship. It is not specified for each individual ship. Therefore, in general, since each constant is a value different from the true value specific to the ship, the deceleration amount ΔV and the ship speed V obtained according to the above equations are not accurate values, and can be used as a rough guide. It is only about a value. In addition, there are derived equations other than the equations listed above, but since all of them include similar ship-specific constants, the same problem also occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is intended to solve the above problem by utilizing wave forecast information without using a derivation formula including a ship-specific constant. It is an object of the present invention to be able to derive the speed of a ship decelerated due to the amount of deceleration of the ship or the waves. The present invention enables more accurate route planning and ship operation in a shorter time and with less fuel consumption by achieving this object.

[0006]

In order to achieve such an object, the present invention provides (1) wave forecast information including information on a wave height and an absolute wave direction with respect to a ship position and time, while 2) Enter the actual measured values of the position, course and speed of the ship and the positioning result information indicating the current time from the measuring equipment mounted on the ship, and (3) enter the wave forecast information and the positioning result information Based on this characteristic, the characteristic of the deceleration amount or speed with respect to the wave height and the relative wave direction, that is, the characteristic of deceleration in waves, which is unique to each ship, is sequentially learned.

As described above, in the present invention, by utilizing wave forecast information available through communication with a land station, together with output of a measuring device such as a GPS (Global Positioning System) receiver, a gyro, and a log, Learn the deceleration characteristics in waves. Since this learning is based on the output of the measurement equipment mounted on the ship and the wave forecast information available on the ship, the resulting wave deceleration characteristic is the wave deceleration characteristic of the ship. It is a characteristic. Therefore, when drafting an operation plan of a ship or the like, a more accurate deceleration amount or speed than before can be obtained by using the wave deceleration characteristics obtained by learning.

[0008] Further, by using information on the rotational speed of the engine for propelling the ship for learning, it is possible to obtain, as the wave deceleration characteristic, a wave deceleration characteristic using the rotational speed of the engine as a parameter. . Further, only when the engine speed is within a predetermined range including the engine speed frequently used during normal voyage, learning is sufficient for practical use. Then, at least the positioning result information may be wirelessly transmitted from the ship to the land-based station, and the land-based station may collect and manage this information. In that case, as long as the wave forecast information can be used, the learning can be performed even on a land-based station. The result of the learning may be reflected later on the ship side.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a functional configuration of an apparatus according to an embodiment of the present invention. The device shown in this figure is a device mounted on a ship, and is connected to some of measuring instruments and communication devices mounted on the ship. Specifically, it is connected to measuring equipment such as a GPS receiver, a heading / water speed meter, a main engine tachometer, and a wireless communication device that can be used for communication with a land station for receiving wave forecast information. ing. Among them, the GPS receiver is a device that receives a signal from a GPS satellite and measures a current position, a moving speed, and the like of a mounting ship. The output of the current position PG from the GPS receiver is normally an output in the form of latitude / longitude (Longitude / Latitude: L / L). From the GPS receiver, UT
An output of the current time TG synchronized with C (Universal Time) is also obtained. A so-called GPS with multiple GPS receivers
When functioning as a gyro, information on the course (heading) of the ship is also obtained. In addition, the heading / water speed meter measures the course θ and speed v
That is, it is a device for measuring the course and speed based on the water surface. Examples include a gyrocompass and an electromagnetic log. The main engine tachometer is a device for detecting the number of revolutions of the engine propelling the ship, specifically, the number of revolutions n of the propeller.

The apparatus according to this embodiment includes a time / position input unit 10, a wave forecast information storage unit 12, and an averaging / storage unit 1.
Four.

First, the time / position input section 10 inputs information relating to the position PG (x, y) of the mounting ship and the current time TG from the GPS receiver. Time / position input unit 10
Further, according to the arrival of the forecast time t, the position PG (x,
y) and information about the current time TG are output. Here, the forecast time t is the forecast time of the wave forecast information described later, and is usually 0:00 or 12:00 in UTC. When the current time TG obtained from the GPS receiver coincides with the forecast time t (however, a difference that can be regarded as substantially coincident is allowed), the time / position input unit 10 outputs the current time TG, Forecast time t and its time t
Is output to the wave forecast information storage unit 12 with the position PG (x, y) which is the measurement result in.

The wave forecast information storage unit 12 has a function of storing and holding wave forecast information. The wave forecast information is, for example, information obtained through data communication with a land station by a wireless communication device (not shown), and includes information that gives a wave height wh and a wave direction wd for each point specified by the latitude x and the longitude y. In. More specifically, the wave forecast information is along a mesh that partitions the earth's surface into virtual grids of about 2.5 degrees latitude × 2.5 degrees longitude, that is, a representative point of each grid, for example, the center or Vertex latitude x and longitude y
Is information that gives information on the wave height wh and the wave direction wd in association with. Since the wave forecast information is usually updated once a day (including the forecast up to several days in advance), the wave height wh and the wave direction wd in the wave forecast information are further associated with the forecast time t. I can say. Therefore, in the present application, the wave height wh and the wave direction wd in the wave forecast information are set to the wave height wh.
(T, x, y) and the wave direction wd (t, x, y). The wave height wh (t, x, y) usually represents a significant wave height, and its unit is m. Wave direction wd (t, x,
y) is usually the dominant wave direction with reference to a predetermined azimuth (that is, the absolute wave direction), and its unit is degree. In applications such as this embodiment, the resolution of the wave height wh (t, x, y) is:
It may be about 0.1 m or about 0.5 m. Wave direction w
The resolution of d (t, x, y) may be about 16-minute azimuth, that is, for example, such that "north-northeast" and "northeast" can be distinguished.

The wave forecast information storage unit 12 stores
Maintain the latest wave forecast information that is still reliable. For example, every time new wave forecast information is received from the land station, the old wave forecast information is discarded. If a predetermined period of time, for example, three days, has passed since reception, the wave height wh and the wave height can be accurately determined even if the wave forecast information is no longer used. It is considered that the direction wd cannot be obtained and the wave forecast information is discarded.
In this way, only the latest wave forecast information that is sufficiently new is held. Alternatively, the wave forecast information received from the land station is retained for a predetermined period of time, for example, three days in the past, and the wave forecast information after a predetermined period of time, for example, three days, is discarded (or when the latest wave forecast information is received). The oldest wave forecast information among the stored information is discarded). In any case, the wave forecast information storage unit 12 stores at least the wave height wh (t,
Wave forecast information including information on (x, y) and the wave direction wd (t, x, y), which is up-to-date and still worthy of trust and use, is retained.

When information on the time t and the position PG (x, y) is given from the time / position input unit 10, the wave forecast information storage unit 12 stores the latest and reliable information among the stored wave forecast information. From the position PG (x,
By selecting the wave forecast information for the position closest to y), the wave height wh (t, x, y) and the wave direction wd (t, x, y) at the position PG (x, y) at time t are calculated as follows: Ask. Wave height wd (t,
(x, y) is a wave direction based on a predetermined azimuth, that is, an absolute wave direction. Therefore, the wave forecast information storage unit 12 inputs a heading (heading θ) from a heading gauge such as a gyro, and outputs a wave direction wd.
(T, x, y) is converted into a wave direction represented by the bow direction reference, that is, a relative wave direction wd ′ (t, x, y). The wave forecast information storage unit 12 further obtains, from the heading / water speed meter, a measurement result of the water speed v, which is information representing the speed of the mounting ship,
input. As a result, information on the wave height and wave direction at the current time and the current position and information on the speed of the loading ship at the current time are prepared. The wave forecast information storage unit 12 stores the wave height wh at the current time and the current position.
(T, x, y) and the wave direction wd (t, x, y) are associated with the speed given by the water speed v, and the resulting boat speed information s (wh, wd) is averaged.・ Storage unit 1
4 In addition, as a water speed meter, water speed v
Instead of a type that outputs the measurement result as it is, it is better to use a type that outputs a moving average or the like, that is, a type that outputs a minute output change or an output change at a high frequency after smoothing. Alternatively, it is desirable to execute this averaging process in the wave forecast information storage unit 12. The same applies to the heading (heading θ). Instead of the heading (heading θ), use azimuth information obtained from the GPS receiver (tracking. Since it is based on the ground, it does not always match the heading θ based on the water surface. An error occurs especially in water areas with fast tides). Can also.

The speed information s (wh, wd ') having the wave height wh and the wave direction wd' as variables or parameters is supplied to the averaging / storage unit 14. Averaging·
The storage unit 14 stores the boat speed information s (wh, wd ′) as a parameter of an output of a main engine tachometer (not shown), that is, a measurement result related to the propeller speed n of the marine propulsion engine. The averaging / storage unit 14 stores the ship speed information s (wh, w
d ′) and the propeller speed n are accumulated each time they are obtained. As a result, for example, a wave deceleration characteristic in waves as illustrated in FIG. 2 is obtained. That is, as also appears in the relational formulas listed above as the prior art, the amount of deceleration of the ship due to the waves is an amount that can be substantially determined by the significant wave height and the dominant wave direction, and exhibits characteristics unique to the ship. Quantity. The speed of a ship in waves is generally determined by the rotation speed of the ship propulsion engine in addition to the above. Therefore, by combining the ship speed information s (wh, wd ') with the measured propeller speed n, it is possible to obtain the wave deceleration characteristics.

Further, the ship speed information s (wh, w
When accumulating d ′) and the number of revolutions of the propeller n, averaging is performed by, for example, performing filtering using a first-order lag characteristic or performing an operation such as a moving average to suppress variations in speed.
If possible, the ship speed information s is obtained sequentially so that the curve representing the wave deceleration characteristics (the curve shown in FIG. 2) becomes smooth.
Correction is made to (wh, wd ') and the stored information about the adjacent point on the same curve. Through the learning through the averaging and the correction, it is possible to obtain a stable wave deceleration characteristic in which the fluctuations and errors of the measured values are preferably eliminated.
In order for the information stored by the averaging / storage unit 14 to quickly converge to the intended wave deceleration characteristics in waves,
For example, it is desirable that appropriate initial data such as information collected at the time of test operation and characteristics assumed at the time of design at a shipyard be written in the averaging / storage unit 14 in advance.

The wave deceleration characteristics thus obtained are peculiar to the ship on which they are mounted. In other words, the shape and structural characteristics of the ship, the state of fouling of the ship, the degree of aging of the ship or its mounted equipment, the accuracy and tendency of the measurement equipment mounted on the ship (error occurrence, etc.) ),
It reflects the characteristics of the wave forecast information (for example, the characteristics that the numerical values are higher) and the like. Therefore, by deriving the amount and speed of deceleration in waves using the deceleration characteristics in waves, the reliability is closer to the actual value compared to the derivation by the conventional method of switching constants according to the type and type of ship. And the deceleration amount and speed suitable for the ship can be derived. as a result,
It is possible to accurately formulate a route plan that considers the weather.

In the example shown in FIG. 2, wd ', n is treated as a discrete parameter for the purpose of saving storage capacity and the like. That is, wd 'is 180, 12
For n, 113, 107,...
As such, it is rounded to discrete values. If characteristics relating to intermediate parameters are required, interpolation calculation may be performed. Similarly, wh can be a discrete value. Further, in normal navigation, the ship propulsion engine is often rotated at a rotation speed of about 85% load. Therefore, only when the rotation speed n obtained by the main engine tachometer takes a value of 85% of the specified rotation speed corresponding to 100% load and a value in the vicinity thereof,
The boat speed information s (wh, wd ') may be stored in the averaging / storage unit 14. As a result, the amount of storage can be saved, and there is no particular problem in the course planning. Further, the information input by the time position input unit 10 or the information input from the water speed dynamometer, or the ship speed information s obtained therefrom
(Wh, wd ') may be wirelessly transmitted to the land station. In that case, a function corresponding to the averaging / storage unit 14 can be provided on the land station side. In other words, the land-based station can obtain the results of the actual measurement learning for each ship of the deceleration characteristics in waves that can be used for drafting a route plan. In addition, the “wave direction” shown in FIG. 2 is strictly the dominant wave direction with respect to the course of the ship, and the wave direction wd included in the wave forecast information is global information, that is, information based on a predetermined direction. In addition, information on the course of the loading ship is obtained from a sensor such as a gyro or obtained by time measurement of the position PG (x, y) to compensate for a difference between the two directions. Further, theoretically, the wave cycle, wind power, wind direction, cargo condition, and the like are also related to the wave deceleration characteristics. Therefore, where possible, these are also used as learning materials. However, if the number of parameters is too large, the learning content becomes complicated. Therefore, in practice, it is desirable to perform learning as in the present embodiment. Furthermore, instead of the course θ, the GPS
When using the route obtained from the receiver, it is desirable to perform processing such as discarding data obtained in a water area with a fast tide.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a functional configuration of an apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a wave deceleration characteristic calculated and stored by an averaging / storage unit.

[Explanation of symbols]

10 time / position input unit, 12 wave forecast information storage unit,
14 Averaging and storage unit.

Claims (4)

[Claims] 1. While maintaining wave forecast information including information on a wave height and an absolute wave direction with respect to a ship position and time, an actual measurement of the ship position, course and speed of the ship from a measuring instrument mounted on the ship. Enter the value and the positioning result information indicating the current time, and based on the wave forecast information and the positioning result information, the characteristics of the deceleration amount or speed with respect to the wave height and relative wave direction, that is, the wave deceleration, which is unique to each ship A method characterized by learning characteristics sequentially. 2. The method according to claim 1, further comprising using information on the number of revolutions of an engine for propulsion of the ship, so as to reduce the in-wave deceleration characteristic by using the number of revolutions of the engine as a parameter. A method characterized by learning deceleration characteristics sequentially. 3. The method according to claim 1, wherein the learning is performed only when the rotational speed of the engine is within a predetermined range including a rotational speed frequently used during normal voyage. 4. The method according to claim 1, wherein at least the positioning result information is wirelessly transmitted from the ship to a land-based station, and the learning is performed by using one of a land-based station and the ship. A method characterized by being performed by both parties.