JPH0619476B2 - Tidal current commutation timing prediction method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tidal current commutation timing prediction method for predicting the tidal current commutation timing in a strait or narrow water supply.

[Prior art]

Ships that pass through the strait or narrow water supply may not be able to operate freely before and after tidal current changes, especially before and after commutation in which the direction of the flow changes, causing collisions with other ships, landing on reefs, and other marine accidents. There is a risk. As measures against this, conventionally, the tidal table announced by the Japan Coast Guard is used to predict changes in tidal current, or the signal board is mechanically inverted by the direction of the ocean current as a tidal current signal. It was displayed.

However, there is a problem in that it is impossible to predict the local tidal current change in the strait or narrow water supply, especially the commutation time, by the method of predicting the tidal current change using the tide table. Further, in the case where the signal plate is mechanically inverted depending on the direction of the ocean current, the method of displaying only the direction of the tidal current has a drawback that it is extremely difficult to predict the tidal current change, especially the commutation time.

As a countermeasure against this, the applicant has previously developed a power flow prediction method and applied for a patent (Japanese Patent Application No. 60-197299).
(JP-A-62-58186)}. This tidal current forecasting method creates an approximate expression indicated by those data from past observed tidal current data (tidal current data), calculates an error from a predicted value by the approximate expression and a value from the observed data, and calculates the error at a certain time. Uncertainty of the forecasted value immediately before the commutation by predicting the time (commutation time) to reach the commutation determination angle (determined by the applicable sea area) by performing the grade evaluation corresponding to the amount of error and obtaining the correction angle. In order to eliminate (detailed later), the prediction is fixed when it enters a predetermined range of the commutation prediction time.

[Problems to be solved by the invention]

However, although the above tidal current prediction method has the effect of eliminating the instability of the forecasted value forecast immediately before the time of commutation, as will be described in detail later, the predicted timing of the commutation and the actual commutation timing depend on the unique situation of the tidal current. There is a problem in that a large error may occur, which may hinder the proper operation of the sailing ship.

The present invention has been made in view of the above points, and eliminates the instability of the predicted value forecast immediately before the time of commutation, and greatly reduces the predicted commutation timing and the actual commutation timing depending on the peculiar situation of the tidal current. An object of the present invention is to provide a tidal current commutation timing prediction method that does not cause an error.

[Means for solving problems]

In order to solve the above problems, the present invention observes a tidal current, creates tidal current data from the observation result, stores the tidal current data for a certain period of time, and calculates a current direction and an angle-converted current direction by the stored past tidal current data. Create an approximation formula shown below, calculate the error between the predicted value of the flow direction value at the time of acquisition of observation data predicted by the approximation formula and the ground of the flow direction angle based on the observation data, and perform grade evaluation at regular time intervals. The correction angle is calculated by, and the commutation time is calculated and predicted by the correction angle, and in the vicinity of the time when the tidal current velocity becomes zero, the predicted value of the flow velocity and the observed value are compared, and the difference between the two is within a predetermined range. In the case of outside, newly create an approximate expression of the flow velocity and time from the observed value of the flow velocity, update the approximate expression until the difference between the two falls within a predetermined range, and continuously update the correction angle by the guilade evaluation, According to the updated approximation It was configured to change in the calculation prediction of commutation time.

[Action]

According to the present invention, an error between the predicted value at the time of observation data acquisition in which the flow direction angle is predicted by the approximate expression and the flow direction angle obtained from the observation data at the time of acquisition is calculated, and the error is graded at regular intervals. By calculating the correction angle and calculating and predicting the commutation timing based on the correction angle, the predicted value of the flow velocity and the observed value are compared in the vicinity of the commutation timing when the flow velocity of the tidal current becomes zero, and the difference between the two is determined. If the value is out of the range, a new approximation formula for the flow velocity and time is newly created from the observed value of the flow velocity until it reaches the predetermined range, and the correction angle is continuously updated by grade evaluation, and the commutation timing of the updated approximation formula is calculated. Since the calculation is changed to the prediction, it is possible to make the predicted value of the commutation timing substantially coincide with the actual commutation timing.

〔Example〕

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

FIG. 2 is a block diagram showing the system configuration of a data processing device used in the tidal current commutation timing prediction method of the present invention. As shown in the figure, this data processing device is
The data processing device 3 processes the observation signal of the flow velocity and the flow direction of the tidal current from the tidal current sensor 2 which is sunk in the revision of the predetermined location of
It is sent to the signal device 4, and in the signal processing device 4, tidal current prediction data such as the tidal current direction, velocity and commutation time is displayed on the display panel 5 which can be observed from a ship navigating the strait or narrow water supply, or The tidal current prediction data is notified to the marine vessel by voice through the voice reproduction device 6 and the speaker 7.

FIG. 3 is a block diagram showing the configuration of the data processing device 3. As shown in the figure, the data processing device 3 receives the observation signals of the flow velocity and the flow direction of the tidal current from the tidal current sensor 2 in a central processing unit (CPU) 22. Input to the central processing unit 22
Input / output (I /
O) circuit 21, storage device 23, printing device 24, operation panel 2
5, the CRT 26 and the like, the central processing unit collects the observation signals of the flow velocity and the flow direction from the tidal current sensor 2, stores the observation data in the storage device 23, and based on these observation data, the commutation time, etc. The tidal current prediction value is calculated, and a forecast is issued to the marine vessel through the display panel 5 and the speaker 7. As shown in FIG. 2, the tide flow of the strait or narrow channel 1 becomes westward or eastward as shown by arrow A or B, and further becomes a vortex as shown by arrow C or D. Or

FIG. 4 is a diagram showing the flow direction and flow velocity of the tidal current in the strait or narrow water supply 1. As shown in the figure, the direction of the tidal current changes, that is, commutation occurs at the points of time t _1, t _2, t _3, ... At which the flow velocity changes with time and the flow velocity becomes zero. The velocity and direction of this tidal current can be approximated by the following equation.

Y (t) = Σ {a _i sin (c _i t + k) b _i cos (d _i + k)} ... (1) where the flow velocity is the absolute value of Y (t) and the flow direction is the 4 is a phase angle of FIG. If this phase angle is θ, θ = sin ⁻¹ {Y (t) / MaxY (t)} ± 2n π = sin ⁻¹ {Σ {a _i sin (c _i t + k) + b _i cos (d _i + k)} / Max {Σa _i sin (c _i t + k) + Σb _i cos (d _i + k)}] ± 2nπ where Σb _i cos (d _i + k) is independent of the time and It corresponds to the bias value (DC component added to AC).
In most cases, this value is close to zero, and in this case, θ = sin ^-1 [Σa _i sin (c _i t + k) / Max Σa _i sin (c _i t + k)] ± 2n
π In addition, Y (t) is often repeated at almost the same cycle, so if a _i and c _i are represented by a and c, respectively, θ = sin ⁻¹ {sin (ct + k) / 1 } ± 2nπ = ct + k ± 2nπ.

However, k, c _i , and d _i are fixed constants determined by the operation of the celestial body,
a _i and b _i are coefficients determined from past observation data, t
Is time. Since k, c _i , d _i , a _i , and b _i change with time, i = 1, 2, 3, ... If the flow velocity and flow direction of the tidal current can be expressed by the above approximate expression, the above coefficient a can be calculated from the observation data of a certain past period (i = 1, 2, 3, ...).
_i , b _i are obtained, and the time when the flow of the tidal current changes, that is, the so-called commutation time can be predicted by the observation data from the tidal current sensor 2.

The central processing unit 22 calculates the coefficients a _i and b _i from the past observation data, and predicts the flow velocity and the flow direction of the tidal current based on the observation time based on the observation data at every predetermined time. that time,
Regarding the flow direction, the predicted value is corrected at each of the predetermined observation times by the grade evaluation method described later.

FIG. 6 is a diagram showing a flow of processing for commutation prediction.
The flow direction angle θ is determined from the observation data from the tidal current sensor 2 (step 201). Next, the flow direction angle θ'of the predicted value is obtained based on the above equation (1) (step 202). The flow direction angle θ ′ of these predicted values and the flow direction angle θ from the observed data are compared, and the angle difference between them, that is, the angle error θe (θ′−θ = θe)
Is calculated (step 203). The angle error θe is obtained by grade evaluation described later to obtain a correction angle Δθ (step 204), a correction angle θ ″ = θ ′ + Δθ obtained by correcting the flow direction angle θ ′ of the predicted value is obtained (step 205), and the prediction is performed in advance. The predicted commutation time is changed (step 206).
When a predetermined time (for example, 15 minutes) has elapsed (step 20
7) return to step 201 and repeat the above process,
That is, the processing for prediction is periodically performed at predetermined time intervals to improve the accuracy of prediction of commutation time.

FIG. 7 is a diagram showing the relationship between grade evaluation and correction angle.
As shown in the figure, the grade is divided into five stages of A, B, C, D and E according to the magnitude of the angle error θe, and a correction angle Δθ is given according to each grade A to E. That is, in step 204 of the processing flow of FIG. 6, the correction angle Δθ is obtained by referring to the table shown in FIG. 7 stored in the storage device 4, and in step 205, the prediction correction, that is, the correction angle Δθ is calculated. Then, a correction angle θ ″ = θ ′ + Δθ obtained by correcting the flow direction angle θ ′ of the predicted value is obtained.

As described above, the approximate expression shown by these past observation data is obtained from the observation data of the past fixed period, and the flow direction angle from the observation data obtained by the observation and the flow direction angle of the predicted value obtained by the approximation expression are obtained. The method of determining the angle error of the, estimating the angle error and predicting the commutation time is accurate if the flow direction of the tidal current changes accurately with time as shown in FIG. As shown in FIGS. 5 (a) and 5 (b), the predicted commutation timing may be earlier or later than the actual observed commutation timing depending on the unique situation of the tidal current. Fifth
Figures (a) and (b) are enlarged views of the portion A in Figure 4,
The figure (a) shows the case where the predicted commutation time is earlier than the actual
Ta is the time when the commutation time is predicted in the conventional grade evaluation, Tb is the predicted commutation time predicted thereby, and Tc is the actually observed observed commutation time. The figure (b) shows the case where the predicted commutation time is later than the actual time, Td is the time when the commutation time is predicted by the conventional grade evaluation method, Te is the predicted commutation time predicted thereby, and Tf is the actual time. Indicates the observed observation commutation time.

Therefore, in this embodiment, the observed current commutation time Tb in FIG. 5B is actually observed while the observed current commutation time Tc in FIG. 5B is actually observed. Processing is performed to bring it closer to Tf.

FIG. 1 is a flowchart showing the flow of processing of the tidal current commutation timing prediction method according to the present invention. In FIG. 6, the grade evaluation correction angle in step 101 is the step 20 in FIG.
This is equivalent to obtaining the correction angle Δθ by grade evaluation of No. 4, and the prediction correction of Step 102 is Step 20 of FIG.
5 corresponds to the predictive correction, that is, the predictive correction for obtaining the corrected angle θ ″ = θ ′ + Δθ obtained by correcting the flow direction angle θ ′ of the predicted value by the corrected angle Δθ.

When the correction angle Δθ is obtained by the grade evaluation in step 101, the commutation prediction time is corrected (step 102). That is, the correction angle θ ″ = θ ′ + Δθ is obtained. In this case, the correspondence between each time until the commutation time, that is, the time when the flow velocity of the tidal current becomes zero and the tidal current velocity is predicted. Prediction / observation comparison processing for comparing the predicted value predicted at each of the times with the observed value actually observed at that time is performed.Next, in step 104, the matching between the predicted value and the observed value is confirmed, If they match, the state in which the predicted value is displayed is continued in step 105. If the predicted value and the observed value do not match in step 104, a sample of the observed value of the flow velocity is collected in step 106, and the sample before that time is collected. Approximate expression creation processing is performed including the specified amount of observation data (step 10).
7). In this case, an example of a typical approximate expression is y = kx ⁿ . Here, y = change in tidal current velocity x = time k = constant n = constant. Next, the predicted value of the tidal current velocity at each time obtained using the approximate expression obtained in step 107 is compared with the observed value of the tidal current velocity actually observed at that time (step 108). Determine match (step 1
09), if they match, the process moves to the display of step 105. If they do not match, the process returns to the sample collection of the observed value of the tidal current velocity in step 106, and the processes from step 106 to step 109 are executed.

A specific example of the above processing will be described below.

Assuming that the flow velocity at Ta in FIG. 5 is ya and the flow velocity at the next observation is ya ₁ , the difference in flow velocity in this case Δya ₁
When the time interval of Δya ₁ = ya-ya ₁ flow velocity observation is regarded as a unit time, x = 1, and Δya ₁ = k is obtained. When the flow velocity ya ₂ is obtained as the next observation value, ya
The difference Δya ₂ from Δya ₂ is Δya ₂ = Δya ₁ 2 ² (∵x = 2). That is, logΔya ₂ = logΔya ₁ + nlog2, and since Δya ₂ and Δya ₁ are known here, n is calculated as n = (logΔya ₂ −logΔya ₁ ) / log ₂ . Sweet potato above ya, ya ₁ , ya
_From the observation of ₂ , an approximate expression of the flow velocity change can be obtained. Although will be now able to predict for the third round of the measured values ya _3, the result of the prediction, if the error between the actual measurement value ya ₃ is recognized as the range that do not operational problems, the approximate expression 4th If it is determined that this error is large, the approximate expression is updated in the same procedure as above using the second and third actual measurements. This operation is repeated to bring the predicted value closer to the actual commutation time.

〔The invention's effect〕

As described above, the tidal current commutation timing prediction method according to the present invention, until near the final commutation timing, the error between the predicted value of the flow direction angle at the time of observation data acquisition predicted by the approximate expression and the value from the observation data. Calculated, the grade is evaluated at regular intervals of the error, the correction angle is calculated by the grade, the commutation timing is calculated and predicted by the correction angle, and in the vicinity of the commutation timing when the flow velocity of the tidal current is zero, The estimated value of the flow velocity is compared with the observed value, and the approximation formula is continuously updated until the difference between the two falls within a predetermined range, and the commutation time is predicted by the updated approximation formula. Compared with the case where the calculation and prediction of the commutation time is performed only by continuously updating the correction angle, the tidal current commutation time can be accurately predicted, which is extremely effective for safe navigation of a ship traveling in the strait or narrow water.

[Brief description of drawings]

FIG. 1 is a flow chart showing the flow of processing of the tidal current commutation timing prediction method according to the present invention, FIG. 2 is a block diagram showing the system configuration of the tidal current prediction apparatus, and FIG. 3 is the system of the data processing apparatus of FIG. Block diagram showing the configuration, FIG. 4 is a diagram showing the flow direction and flow velocity of the tide of the strait or narrow water supply, and FIGS. 5 (a) and 5 (b) are enlargements of part A (near commutation timing) of FIG. FIG. 6 is a diagram showing a flow of processing for commutation prediction,
FIG. 7 is a diagram showing the relationship between grade evaluation and correction angle. In the figure, 1 ... Channel or narrow water supply, 2 ... Tidal current sensor, 3 ...
… Data processing device, 4 …… Signal device, 5 …… Display panel, 6
...... Voice playback device, 7 ... speaker, 21 ... input / output circuit, 22 ... central processing unit, 23 ... storage device, 24 ...
… Printing device, 25 …… Operation panel, 26 …… CRT.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazuo Ibarata 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (56) References Japanese Patent Publication 4-31358 (JP, B2)

Claims (1)

[Claims] 1. A tidal current is observed, tidal current data is created from the result of the observation, the tidal current data is stored for a certain period of time, and an approximate expression indicating a current direction and an angle-converted current direction is created from the stored past tidal current data. Calculating the error between the predicted value of the flow direction angle when acquiring the observation data predicted by the approximate expression and the value of the flow direction angle based on the observation data, performing grade evaluation at regular time intervals, and calculating the correction angle according to the grade , The commutation timing is calculated and predicted from the correction angle, and the predicted value of the flow velocity and the observed value are compared near the time when the tidal current velocity becomes zero, and the flow velocity is observed if the difference between the two is outside the specified range. An approximate expression of the flow velocity and time is newly created from the value, the approximate expression is updated until the difference between the two is within a predetermined range, and the continuous update of the correction angle by the grade evaluation is performed by the updated approximate expression. Prediction of commutation time by Trends commutation timing prediction method characterized by further.