Ship structure ice load peak value and period effective extraction method, program, equipment and storage medium

Abstract

The invention belongs to the technical field of load identification and analysis, and particularly relates to an effective extraction method, program and equipment for a peak value and a period of an ice load of a ship structure and a storage medium. According to the method, on the basis of mobile retrieval and local judgment thoughts, the valley value decline factor is introduced, multiple judgment is carried out on the position relation between two adjacent peak values and the valley value between the two adjacent peak values, and the refinement degree of extraction of characteristic parameters such as the ice force peak value event, the corresponding ice load peak value and the period can be remarkably improved. According to the method, a peak value interval factor is introduced before peak value extraction, and interference of signal burrs on the extraction process can be effectively eliminated by judging the relation between the time interval of two adjacent peak values and the data sampling period; threshold value screening is carried out after peak value extraction, and convenience can be provided for accurate calculation and synchronous extraction of the ice load period. The method is novel in form and high in subsequent expansibility, and can be used as a novel, efficient and reliable ship structure ice load peak value and period extraction tool.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of load identification analysis, and particularly relates to a method, program, device and storage medium for effectively extracting ice load peak value and period of a ship structure. BACKGROUND

[0002] Ice load is the primary threat to the safety of polar ship navigation in ice area, and real ship monitoring is a relatively direct and effective way to obtain ice load. The technical route is to place strain sensors on the load-bearing components at typical ice-breaking positions, and then input the measured ice impact strain into the identification model to solve the ice load. Since the ice-breaking process of the ship has strong randomness, the peak value, period and other characteristic parameters are usually extracted from the identification results, and the distribution characteristics of the ice load are studied based on statistical analysis of the above parameters.

[0003] However, in addition to sea ice impact, the ship will also be subjected to open water resistance or wave load during ice-breaking, although the resulting strain response is small, but it will also cause changes in the readings of the strain sensor. Therefore, the identification results not only contain ice load, but also inevitably mix other components. In order to extract the sea ice impact event and the corresponding ice load peak value, period and other characteristic parameters from it, the existing method defines the time when the time history curve crosses the preset load horizontal line (threshold) as the start and end points of the event, and the maximum load between the start and end points is the only ice load peak value in the event, while the peak values that do not exceed the threshold and are less than the maximum load are all discarded, and the ice load period is defined as the difference between the start and end times. However, there will also be a significant unloading process in the time history curve, in which the load level does not drop below the threshold. This situation may also be caused by sea ice damage or ship-ice relative motion. Therefore, the above method lacks rationality and cannot effectively extract all ice load peak values and periods from the identification results, making it difficult to provide reliable data support for the study of ice load distribution characteristics. SUMMARY

[0004] The purpose of the present application is to provide a method, program, device and storage medium for effectively extracting ice load peak value and period of a ship structure, which can further separate several independent ice force peak value events from sea ice impact events, and accurately extract all ice load peak values and periods to meet the needs of current ice load distribution characteristic research.

[0005] An effective extraction method of ice load peak and period of ship structure, the ice load identification result time curve is obtained, for two adjacent peaks and the valley value between them in the ice load identification result time curve, the valley value drop factor is introduced to judge the drop degree of the valley value relative to the smaller peak, and the independent ice load peak event is separated out; the peak interval factor is introduced to judge the relationship between the time interval of two adjacent peaks and the data sampling period, and the interference of signal burr on the ice load peak and period extraction process is eliminated; the ice load screening threshold is set, and the occurrence period of the ice load is determined according to the ice load peak greater than the threshold screened out.

[0006] Further, an effective extraction method of ice load peak and period of ship structure, comprising the following steps:

[0007] Step 1: peak-valley value retrieval;

[0008] The data starting point of the ice load identification result time curve is moved to retrieve the i-th data point f(i), and f(i) is judged:

[0009] (1) If f(i)>f(i-1) and f(i)>f(i+1), f(i) is a peak P;

[0010] (2) If f(i)<f(i-1) and f(i)<f(i+1), f(i) is a valley V.

[0011] The judgment of the valley value must be carried out after the peak value is retrieved, so as to ensure that the data points are arranged in the order of "peak-valley-peak"; if two peak values and several valley values have been retrieved, step 2 is started to be executed; otherwise, step 1 is continuously executed;

[0012] Step 2: peak-valley value and action period extraction;

[0013] The previous peak value retrieved in step 1 is P1, the latter peak value is P2, and the minimum value of the valley value is V min , the time interval of P1 and P2 is Δt, and the sampling period of the data is T;

[0014] The peak interval factor η is introduced, η>1, and the corresponding operation is executed according to the following peak interval and sampling period relationship:

[0015] (1) If Δt≤ηT and P1<P2, P1 is a signal burr, P1 is discarded from the extracted peak value, P2 is extracted and taken as the previous peak value for the next round of judgment; if the valley value extracted in the last round is greater than V min , it is discarded and V min is extracted, and the valley value retrieved in this round is not brought into the next round;

[0016] (2) If Δt≤ηT and P1>P2, then P2 is a signal glitch, extract P1 and take it as the previous peak value for the next round of judgment, and take the valley value searched in this round into the next round;

[0017] (3) If Δt>ηT, then P1 and P2 are not signal glitches, then further introduce a valley value descending factor ξ, 0<ξ<1, and perform corresponding operations according to the following peak-valley value position relationship:

[0018] (3-1) If V min <ξmin(P1,P2), then extract P1, P2 and V min , take P2 as the previous peak value for the next round of judgment, and do not take the valley value searched in this round into the next round;

[0019] (3-2) If V min >ξmin(P1,P2) and P1 min , then discard the valley value extracted in the last round and extract V min , and do not take the valley value searched in this round into the next round;

[0020] (3-3) If V min >ξmin(P1,P2) and P1>P2, then extract P1 and take it as the previous peak value for the next round of judgment, and take the valley value searched in this round into the next round;

[0021] If the time corresponding to the ith extracted peak value and valley value is t P (i) and t V (i) respectively, then the action period of the load is t V (i+1)-t V (i), the loading time is t P (i+1)-t V (i), and the unloading time is t V (i)-t P (i). The above parameters are extracted synchronously;

[0022] Step 3: Threshold screening and occurrence period extraction;

[0023] According to the noise level in the ship open water navigation data, set the ice load screening threshold α, eliminate the peak value and its two adjacent valley values less than α from the extraction results of step 2, and synchronously eliminate the associated load action period, loading time and unloading time; if the time corresponding to the jth ice load peak value screened out is t P (j), then the occurrence period of the ice load is t P (j+1)-t P (j).

[0024] A computer device / system, comprising a memory, a processor and a computer program stored on the memory, the processor executing the computer program to implement the steps of the above method for effective extraction of ice load peak and period of ship structure.

[0025] A computer readable storage medium having stored thereon a computer program / instructions, which, when executed by a processor, implement the steps of the above method for effective extraction of ice load peak and period of ship structure.

[0026] A computer program product comprising a computer program / instructions, which, when executed by a processor, implement the steps of the above method for effective extraction of ice load peak and period of ship structure.

[0027] The present application has the following advantages:

[0028] The present application is based on the idea of mobile search and local determination, introduces a valley drop factor, and through multiple determinations of the positional relationship between two adjacent peaks and the valley therebetween, can significantly improve the refinement degree of extraction of ice force peak event and corresponding ice load peak, period and other characteristic parameters. The present application introduces a peak interval factor before peak extraction, determines the relationship between the time interval of two adjacent peaks and the data sampling period, and can effectively eliminate the interference of signal burrs on the extraction process; threshold screening is performed after peak extraction, which can facilitate accurate calculation and synchronous extraction of ice load period. The present application is novel in form, has strong follow-up expandability, can be used as a new, efficient and reliable tool for extraction of ice load peak and period of ship structure, and has certain research and application value in the field of load identification and analysis technology. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The present application is based on the idea of mobile search and local determination, introduces a valley drop factor, and through multiple determinations of the positional relationship between two adjacent peaks and the valley therebetween, can significantly improve the refinement degree of extraction of ice force peak event and corresponding ice load peak, period and other characteristic parameters. The present application introduces a peak interval factor before peak extraction, determines the relationship between the time interval of two adjacent peaks and the data sampling period, and can effectively eliminate the interference of signal burrs on the extraction process; threshold screening is performed after peak extraction, which can facilitate accurate calculation and synchronous extraction of ice load period. The present application is novel in form, has strong follow-up expandability, can be used as a new, efficient and reliable tool for extraction of ice load peak and period of ship structure, and has certain research and application value in the field of load identification and analysis technology.

[0030] Figure 2 The present application is based on the idea of mobile search and local determination, introduces a valley drop factor, and through multiple determinations of the positional relationship between two adjacent peaks and the valley therebetween, can significantly improve the refinement degree of extraction of ice force peak event and corresponding ice load peak, period and other characteristic parameters. The present application introduces a peak interval factor before peak extraction, determines the relationship between the time interval of two adjacent peaks and the data sampling period, and can effectively eliminate the interference of signal burrs on the extraction process; threshold screening is performed after peak extraction, which can facilitate accurate calculation and synchronous extraction of ice load period. The present application is novel in form, has strong follow-up expandability, can be used as a new, efficient and reliable tool for extraction of ice load peak and period of ship structure, and has certain research and application value in the field of load identification and analysis technology.

[0031] Figure 3 The present application is based on the idea of mobile search and local determination, introduces a valley drop factor, and through multiple determinations of the positional relationship between two adjacent peaks and the valley therebetween, can significantly improve the refinement degree of extraction of ice force peak event and corresponding ice load peak, period and other characteristic parameters. The present application introduces a peak interval factor before peak extraction, determines the relationship between the time interval of two adjacent peaks and the data sampling period, and can effectively eliminate the interference of signal burrs on the extraction process; threshold screening is performed after peak extraction, which can facilitate accurate calculation and synchronous extraction of ice load period. The present application is novel in form, has strong follow-up expandability, can be used as a new, efficient and reliable tool for extraction of ice load peak and period of ship structure, and has certain research and application value in the field of load identification and analysis technology.

[0032] Figure 4 The present application is based on the idea of mobile search and local determination, introduces a valley drop factor, and through multiple determinations of the positional relationship between two adjacent peaks and the valley therebetween, can significantly improve the refinement degree of extraction of ice force peak event and corresponding ice load peak, period and other characteristic parameters. The present application introduces a peak interval factor before peak extraction, determines the relationship between the time interval of two adjacent peaks and the data sampling period, and can effectively eliminate the interference of signal burrs on the extraction process; threshold screening is performed after peak extraction, which can facilitate accurate calculation and synchronous extraction of ice load period. The present application is novel in form, has strong follow-up expandability, can be used as a new, efficient and reliable tool for extraction of ice load peak and period of ship structure, and has certain research and application value in the field of load identification and analysis technology. min The present application is based on the idea of mobile search and local determination, introduces a valley drop factor, and through multiple determinations of the positional relationship between two adjacent peaks and the valley therebetween, can significantly improve the refinement degree of extraction of ice force peak event and corresponding ice load peak, period and other characteristic parameters. The present application introduces a peak interval factor before peak extraction, determines the relationship between the time interval of two adjacent peaks and the data sampling period, and can effectively eliminate the interference of signal burrs on the extraction process; threshold screening is performed after peak extraction, which can facilitate accurate calculation and synchronous extraction of ice load period. The present application is novel in form, has strong follow-up expandability, can be used as a new, efficient and reliable tool for extraction of ice load peak and period of ship structure, and has certain research and application value in the field of load identification and analysis technology.

[0033] Figure 5 The present application is based on the idea of mobile search and local determination, introduces a valley drop factor, and through multiple determinations of the positional relationship between two adjacent peaks and the valley therebetween, can significantly improve the refinement degree of extraction of ice force peak event and corresponding ice load peak, period and other characteristic parameters. The present application introduces a peak interval factor before peak extraction, determines the relationship between the time interval of two adjacent peaks and the data sampling period, and can effectively eliminate the interference of signal burrs on the extraction process; threshold screening is performed after peak extraction, which can facilitate accurate calculation and synchronous extraction of ice load period. The present application is novel in form, has strong follow-up expandability, can be used as a new, efficient and reliable tool for extraction of ice load peak and period of ship structure, and has certain research and application value in the field of load identification and analysis technology. min The present application is based on the idea of mobile search and local determination, introduces a valley drop factor, and through multiple determinations of the positional relationship between two adjacent peaks and the valley therebetween, can significantly improve the refinement degree of extraction of ice force peak event and corresponding ice load peak, period and other characteristic parameters. The present application introduces a peak interval factor before peak extraction, determines the relationship between the time interval of two adjacent peaks and the data sampling period, and can effectively eliminate the interference of signal burrs on the extraction process; threshold screening is performed after peak extraction, which can facilitate accurate calculation and synchronous extraction of ice load period. The present application is novel in form, has strong follow-up expandability, can be used as a new, efficient and reliable tool for extraction of ice load peak and period of ship structure, and has certain research and application value in the field of load identification and analysis technology.

[0034] Figure 6 V min Figure 1 shows a schematic diagram of the case when P1>P2 and P1>P2. DETAILED DESCRIPTION

[0035] The application will be further described below with reference to the accompanying drawings.

[0036] The application provides an effective extraction method for ice load peak and period of ship structure, which can further separate several independent ice force peak events from the ice impact event and accurately extract all ice load peaks and periods to meet the needs of current ice load distribution characteristic research.

[0037] The application introduces a valley value drop factor to determine the drop degree of the valley value relative to the smaller peak value based on the comparison of two adjacent peaks and the valley value therebetween in the time history curve of the ice load identification result, and separates several independent ice force peak events from the ice load identification result; introduces a peak interval factor to determine the relationship between the time interval of two adjacent peaks and the data sampling period to eliminate the interference of signal burrs on the ice load peak and period extraction process; and places the threshold filtering process at the rear end to realize the accurate calculation and synchronous extraction of the ice load action period, loading (unloading) time and occurrence period.

[0038] Step 1: peak and valley value retrieval;

[0039] The data starting point of the time history curve of the ice load identification result is moved to retrieve, and the ith data point is f(i). f(i) is determined according to the following position relationship:

[0040] (1) If f(i)>f(i-1) and f(i)>f(i+1), f(i) is a peak value P.

[0041] (2) If f(i)<f(i-1) and f(i)<f(i+1), f(i) is a valley value V.

[0042] It should be noted that the determination of the valley value should be performed after the peak value is retrieved to ensure that the data points are arranged in the order of "peak-valley-peak". If two peak values and several valley values have been retrieved, step 2 is started to be performed; otherwise, step 1 is continuously performed.

[0043] Step 2: peak and valley value and action period extraction;

[0044] The previous peak value retrieved in step 1 is P1, the latter peak value is P2, the minimum value in the valley value is V min , the time interval of P1 and P2 is Δt, and the sampling period of the data is T.

[0045] A peak interval factor η (η > 1) is introduced, and corresponding operations are performed according to the following peak interval and sampling period relationship:

[0046] (1) If Δt ≤ ηT and P1 < P2, P1 is a signal spur, P1 is discarded from the extracted peaks, P2 is extracted and taken as the previous peak value for the next round of judgment; if the valley value extracted in the last round is greater than V min , it is discarded and V min is extracted, and the valley value searched in the current round is not brought into the next round.

[0047] (2) If Δt ≤ ηT and P1 > P2, P2 is a signal spur, P1 is extracted and taken as the previous peak value for the next round of judgment, and the valley value searched in the current round is brought into the next round.

[0048] (3) If Δt > ηT, both P1 and P2 are not signal spurs, a valley drop factor ξ (0 < ξ < 1) is further introduced, and corresponding operations are performed according to the following peak-valley position relationship:

[0049] (3-1) If V min < ξ min (P1, P2), P1, P2 and V min are extracted, P2 is taken as the previous peak value for the next round of judgment, and the valley value searched in the current round is not brought into the next round.

[0050] (3-2) If V min > ξ min (P1, P2) and P1 < P2, P1 is discarded from the extracted peaks, P2 is extracted and taken as the previous peak value for the next round of judgment; if the valley value extracted in the last round is greater than V min , it is discarded and V min is extracted, and the valley value searched in the current round is not brought into the next round.

[0051] (3-3) If V min > ξ min (P1, P2) and P1 > P2, P1 is extracted and taken as the previous peak value for the next round of judgment, and the valley value searched in the current round is brought into the next round.

[0052] Let the time corresponding to the ith extracted peak and valley value be t P (i) and t V (i) respectively, then the action period of the load is t V (i+1)-t V (i), the loading time is t P (i+1)-t V (i), and the unloading time is t V (i)-t P (i). The above parameters are synchronously extracted.

[0053] Step 3: threshold screening and occurrence period extraction;

[0054] According to the noise level in the open water navigation data of the ship, an ice load screening threshold a is set, peaks less than a and adjacent valleys on both sides of the peaks from the extraction results of step 2 are removed, and the associated load action period and loading (unloading) time are also removed. Let the time corresponding to the jth ice load peak screened out be t P (j), then the occurrence period of the ice load is t P (j+1)-t P (j), and the parameter is synchronously extracted.

[0055] The present application is based on the mobile search and local decision-making idea, introduces a valley drop factor, and through multiple judgments on the positional relationship between two adjacent peaks and the valley therebetween, the fine degree of extraction of ice force peak events and corresponding ice load peak, period and other characteristic parameters can be significantly improved.

[0056] The present application introduces a peak interval factor before peak extraction, and through judgment on the relationship between the time interval of two adjacent peaks and the data sampling period, the interference of signal burrs on the extraction process can be effectively eliminated; threshold screening is performed after peak extraction, which can facilitate accurate calculation and synchronous extraction of ice load period.

[0057] The present application is novel in form and has strong follow-up expandability, and can be used as a new, efficient and reliable tool for extracting ice load peak and period of ship structure, and has certain research and application value in the field of load identification and analysis technology.

[0058] Example 1:

[0059] As Figure 1 shown, the present application provides an effective extraction method for ice load peak and period of ship structure, which includes three steps of peak-valley value search, peak-valley value and action period extraction, threshold screening and occurrence period extraction.

[0060] Step 1: peak-valley value search

[0061] First, the ice load measured data is imported; then, the search is started from the beginning of the data, the position relationship among the adjacent three points f(i-1), f(i), f(i+1) is determined to determine the peak and valley, when two peaks and several valleys are searched, step 2 is started.

[0062] Step 2: peak-valley value and action period extraction

[0063] First, the peak interval factor η is introduced, the relationship between the time interval Δt of two adjacent peaks P1, P2 and the data sampling period T is determined and corresponding operation is performed:

[0064] Figure 2This is the case when Δt≤ηT and P1<P2. Figure 3 This is the case where Δt ≤ ηT and P1 > P2. For both of these cases, extract max(P1, P2).

[0065] Figures 4 to 6 For the case where Δt > ηT, a valley value reduction factor ξ is further introduced, which applies to the minimum value V in the valley. min Determine the positional relationship with the smaller peak value min(P1, P2) and perform the corresponding operation:

[0066] Figure 4 For V min When ξmin(P1, P2) < ξmin(P1, P2), P1 and P2 are treated as the peak values ​​of two independent ice force peak events, and P1, P2 and V are extracted. min .

[0067] Figure 5 For V min The case where ξmin(P1,P2) > and P1<P2. Figure 6 For V min The case where ξmin(P1,P2) and P1>P2. For both of these cases, extract max(P1,P2).

[0068] Finally, based on the extracted time t corresponding to the i-th peak and trough values... P (i), t V (i) Calculate the load's period t V (i+1)-t V (i) Loading time t P (i+1)-t V (i) Unloading time t V (j)-t P (i), and extract the above parameters synchronously.

[0069] Step 3: Threshold Filtering and Periodicity Extraction

[0070] First, an ice load screening threshold α is set based on the noise level in the ship's open water navigation data. Then, peak values ​​smaller than α and their adjacent valley values ​​are removed from the extraction results of step 2, along with associated load application periods and loading / unloading times. Finally, the time t corresponding to the j-th ice load peak value selected based on the threshold is determined. P (j), calculate the occurrence period t of the ice load. P (j+1)-t P (j), and extract the parameter synchronously; finally, output the peak value and period extraction results of ice load.

[0071] The above merely provides the preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the principles and technical scope of the present application shall fall into the scope of the present application.

Claims

1. A method for extracting ice load peak and period of a ship structure, characterized in that: a time history curve of ice load identification result is obtained, for two adjacent peaks and the valley between them in the time history curve of ice load identification result, a valley drop factor is introduced to determine the drop degree of the valley relative to the smaller peak, and independent ice load peak events are separated; a peak interval factor is introduced to determine the time interval of two adjacent peaks and the relationship with the data sampling period, and the interference of signal glitches on the ice load peak and period extraction process is eliminated; an ice load screening threshold is set, and the occurrence period of the ice load is determined according to the ice load peaks greater than the threshold screened out. Starting from the data starting point of the time history curve of ice load identification result, the i th data point is f (i) ; If f (i) > f (i-1) and f (i) > f (i+1), f (i) is a peak P; 2. The method of claim 1, wherein: If f (i) < f (i-1) and f (i) < f (i+1), f (i) is a valley V. The determination of the valley must be carried out after the peak is retrieved, so as to ensure that the data points are arranged in the order of "peak-valley-peak". 3.A method for extracting ice load peak and period of a ship structure according to claim 2, characterized in that: (2) If Δt≤ηT and P1>P2, P2 is a signal glitch, P1 is extracted and taken as the previous peak in the next round of determination, and the valley retrieved in this round is brought into the next round; (3) If Δt>ηT, P1 and P2 are not signal glitches. The previous peak value is P1, the next peak value is P2, and the minimum value in the valley is V min The time interval of P1 and P2 is Δt, and the sampling period of the data is T; a peak interval factor η is introduced, and η>1; (1) If Δt≤ηT and P1 min , then P1 is a signal glitch, P1 is discarded from the extracted peaks, P2 is extracted and taken as the previous peak for the next round of decision; if the valley value extracted in the previous round is greater than V min , then it is discarded and V min is extracted, and the valley value extracted in the current round is not taken into the next round. If Δt>ηT, P1 and P2 are not signal glitches, a valley drop factor ξ is introduced, 0<ξ<1; The steps include:

4. The method of claim 3, wherein: Step 1: peak-valley retrieval; (3-1) If V min If <ξmin(P1, P2), then extract P1, P2 and V min Take P2 as the previous peak value for the next round of determination, and do not bring the valley value searched in this round into the next round. (3-2) If V min > min(P1, P2) and P1 < P2, then P1 is discarded from the extracted peaks, P2 is extracted and taken as the previous peak for the next round of determination; if the valley value extracted in the previous round is greater than V min , then it is discarded and V min is extracted, and the valley value searched in the present round is not taken into the next round. (3-3) If V min > min(P1, P2) and P1 > P2, then extract P1 and take it as the previous peak value for the next round of determination, and take the valley value searched in this round into the next round.

5. A method of efficiently extracting ice load peaks and periods from a ship structure according to claim 4, characterized in that: The time corresponding to the ith extracted peak and valley is t P (i) and t V (i), the action period of the load is t V (i+1)-t V (i), the loading time is t P (i+1)-t V (i), the unloading time is t V (i)-t P (j), the above parameters are extracted synchronously with the peak and valley.

6. A method of efficiently extracting ice load peaks and periods from a ship structure according to claim 5, characterized in that: According to the noise level in the open water navigation data of the ship, an ice load screening threshold a is set, peaks less than a and adjacent valleys on both sides thereof are removed from the extraction results, and the associated load action period, loading time and unloading time are also removed; the time corresponding to the jth ice load peak screened out is t P (j), and the occurrence period of the ice load is t P (j+1)-t P (j).

7. A method for efficient extraction of ice load peaks and periods of a ship structure, characterized by, Starting from the data starting point of the time history curve of ice load identification result, the i th data point is f (i), and f (i) is determined: (1) If f (i) > f (i-1) and f (i) > f (i+1), f (i) is a peak P; (2) If f (i) < f (i-1) and f (i) < f (i+1), f (i) is a valley V. The determination of the valley must be carried out after the peak is retrieved, so as to ensure that the data points are arranged in the order of "peak-valley-peak". If two peaks and several valleys have been retrieved, step 2 is started to be executed; otherwise, step 1 is continued to be executed; Step 2: peak-valley and action period extraction; A peak interval factor η is introduced, η>1, and corresponding operations are performed according to the following peak interval and sampling period relationship: (2) If Δt≤ηT and P1>P2, P2 is a signal glitch, P1 is extracted and taken as the previous peak in the next round of determination, and the valley retrieved in this round is brought into the next round; The previous peak value searched in step 1 is P1, the next peak value is P2, and the minimum value in the valley is V min The time interval between P1 and P2 is Δt, and the sampling period of the data is T. (3) If Δt>ηT, P1 and P2 are not signal glitches, a valley drop factor ξ is further introduced, 0<ξ<1, and corresponding operations are performed according to the following peak-valley position relationship: (1) If Δt≤ηT and P1<P2, then P1 is a signal spike. Discard P1 from the extracted peak values, extract P2 and use it as the previous peak value for the next round of judgment; if the valley value extracted in the previous round is greater than V min Then discard it and extract V. min The valley value found in this round of retrieval will not be carried over to the next round; Step 3: threshold screening and occurrence period extraction; The processor executes the computer program to realize the steps of the method of any one of claims 1 to 7. (3-1) If V min If min(P1, P2) < ξ, then extract P1, P2 and V min Take P2 as the previous peak value for the next round of determination, and do not bring the valley value searched in this round into the next round. (3-2) If V min > min(P1, P2) and P1 < P2, then P1 is discarded from the extracted peaks, P2 is extracted and taken as the previous peak for the next round of decision; if the valley value extracted in the previous round is greater than V min , then it is discarded and P min is extracted, and the valley value extracted in the current round is not taken into the next round. (3-3) If V min > min(P1, P2) and P1 > P2, then extract P1 and take it as the previous peak value for the next round of determination, and take the valley value searched in this round into the next round. The time instants corresponding to the extracted ith peak and trough are t P (j) and t V (j), the action period of the load is t V (i+1)-t V (i), the loading time is t P (i+1)-t V (i), the unloading time is t V (i)-t P (i). The above parameters are extracted synchronously; The computer program / instructions are executed by the processor to realize the steps of the method of any one of claims 1 to 7. According to the noise level in the open water navigation data of the ship, the ice load screening threshold a is set, the peak value less than a and the adjacent valley value on both sides thereof are removed from the extraction result of step 2, and the associated load action period, loading time and unloading time are removed synchronously; if the time corresponding to the jth ice load peak value screened out is t P (j), the occurrence period of the ice load is t P (j+1)-t P (j).

8. A computer apparatus / device / system comprising a memory, a processor, and a computer program stored on the memory, characterized in that: ​ 9. A computer readable storage medium having stored thereon computer programs / instructions, characterized in that: ​ 10. A computer program product comprising computer programs / instructions, characterized in that: The computer program / instructions, when executed by the processor, implement the steps of the method of any one of claims 1 to 7.

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