CN116045899A - Curve recognition method based on inland ship longitude and latitude data - Google Patents

Abstract

The curve identification method based on the longitude and latitude data of inland water ships belongs to the field of ship energy, and is used to solve the problem of fully automatic identification of inland water ship route curves. The longitude and latitude data are segmented, and the longitude and latitude data corresponding to the index are projected into plane coordinates; Perform polynomial fitting on the plane coordinates; calculate the radius of curvature of the plane coordinates of the latitude and longitude data corresponding to the index according to the polynomial fitting result of the plane coordinates; calculate the curvature according to the radius of curvature of the plane coordinates of the latitude and longitude data corresponding to the index The inland river ship cornering speed drop value corresponding to the radius; according to the inland river ship cornering speed drop value, mark the curve corresponding to the longitude and latitude data of the index, and the effect is to automatically and accurately identify the navigation curve through the longitude and latitude data of the inland river ship.

Description

Curve recognition method based on latitude and longitude data of inland ships

technical field

The invention belongs to the field of ship energy management, and in particular relates to a curve identification method used for route segmentation in the early stage of speed optimization of an inland river ship in an energy management method.

Background technique

Energy saving and emission reduction is an important theme in today's era. As a carrier of bulk commodities, ships account for more than 80% of the world's total trade and play an important supporting role in international trade and regional economic development. However, ships are also considered to be the largest contributor to fuel consumption in the transportation industry . According to relevant research, reducing the ship's navigation speed by 2 to 3 knots on the basis of the design speed will greatly reduce the ship's fuel consumption and reduce operating costs. Therefore, speed optimization is a simpler and more efficient way to improve ship energy efficiency.

For inland ships, the route is basically fixed and highly repeatable, and the hydrology of the inland river changes significantly. Especially for container ships and bulk cargo transportation, the demand is stable and the delivery time is stable. Therefore, the optimization of reducing the speed of inland ships under fixed routes Management is important. Under the fixed route, while meeting the requirements of the voyage period, through the optimized management of the voyage speed, the goal of the lowest total fuel consumption and the least carbon dioxide emission can be achieved, and the goal of energy saving, emission reduction and fuel cost reduction for inland waterway ships can be realized.

Based on this, the optimal management of reducing the speed of inland ships under the fixed route requires the support of the route segment in the early stage of the speed optimization of inland ships. Among them, the identification of inland river bends is an important technical route for support. For more accurately identified bends, Requiring the ship to slow down and turn, not only improves the safety of the ship, but also optimizes the management of reducing the speed according to the situation of the bend. In the past, in the route segmentation of inland ship route optimization, scholars usually used manual segmentation according to the route cities: for example, the route from Wuhan to Shanghai was divided into Wuhan-Jiujiang section, Jiujiang-Nanjing section, and Nanjing-Shanghai section. Or use manual segmentation according to the curve in the route map. In this way, the identification of inland river bends usually requires manual marking, which is not efficient and the accuracy is greatly affected by subjectivity.

Contents of the invention

In order to solve the problem of fully automatic identification of inland ship route curves, according to some embodiments of the present application, the method for identifying curves based on inland ship latitude and longitude data includes:

Step 1: Set the index of obtaining N sequential latitude and longitude data through navigation from 0 to N-1;

Step 2: Segment the latitude and longitude data according to the latitude and longitude data of the starting index i, and the segmentation result includes the latitude and longitude data corresponding to index i and index j and all indexes between index i and index j;

Step 3: Project the latitude and longitude data corresponding to index i and index j and all indexes between index i and index j into plane coordinates, and the index of plane coordinates is the same as the index of latitude and longitude data;

Step 4: Carry out polynomial fitting to described plane coordinate;

Step 5: According to the serial numbers i and j of the index i and the index j, determine the index serial numbers k and l; through the polynomial fitting result of the plane coordinates, calculate the index k and the index l and all between the index k and the index l The radius of curvature of the plane coordinates of the latitude and longitude data corresponding to the index;

According to the radius of curvature of the plane coordinates of the longitude and latitude data corresponding to the index k and the index l and all indexes between the index k and the index l, calculate the inland river ship cornering speed drop value corresponding to the curvature radius;

Mark the curves of the longitude and latitude data corresponding to index k and index l and all indexes between index k and index l according to the drop value of the inland waterway ship's cornering speed;

Step 6: re-determine the starting index i according to the serial numbers i and j of the index i and the index j, and the marking serial number of the re-determined starting index is greater than the marking serial number of the starting index;

Step 7: Repeat Step 2-Step 6 until the curve marking of all the latitude and longitude data is completed.

According to some embodiments of the present application, the method for identifying curves based on latitude and longitude data of inland watercraft, the segmented method of step 2 includes

Starting from the latitude and longitude data of the starting index i, the serial number of the index j increases from i+1, and every time one is added, check the difference between the minimum longitude and the maximum longitude of the latitude and longitude data corresponding to all the indexes from index i to index j, where, The value of the difference between the minimum longitude and the maximum longitude is set to x, the minimum value of the fixed number is y, and the maximum value of the fixed number is z;

S2.1. If the difference between the minimum longitude and the maximum longitude is greater than x degrees, the serial number of index j stops increasing. At this time, if j-i is less than y, then the serial number j=i+y, if j-i is greater than y then No operation, get the serial number of index j;

If the difference between the minimum longitude and the maximum longitude is not greater than x degrees, then the sequence number of index j continues to increase until the difference between the minimum longitude and maximum longitude is greater than x degrees, then the sequence number of index j stops increasing. If j -i is less than y, then the sequence number j=i+y, if j-i is greater than y, no operation is performed, and the sequence number of index j is obtained;

If the serial number of the index j increases to exceed i+z and still does not meet the requirement that the difference between the minimum longitude and the maximum longitude is greater than x degrees, the serial number of the index j stops increasing and the serial number j=i+z, and the serial number of the index j is obtained;

S2.2. For the calculation of the sequence number of the obtained index j and the sequence number of the starting index i, through the remainder of (j-i)÷3, the sequence number j is increased or decreased by one or unchanged, so that (j-i) It can be divisible by 3 to obtain the serial number of the final index j, so as to obtain the longitude and latitude data corresponding to all indexes including index i and index j and between index i and index j.

According to the curve identification method based on the latitude and longitude data of inland watercraft in some embodiments of the present application, in the step 3, the latitude and longitude data corresponding to the index i and index j and all indexes between index i and index j are projected into plane coordinates method, including

S3.1. After extracting the segmented index i and index j and the minimum longitude and maximum longitude among all the longitude and latitude data between index i and index j;

S3.2. The central meridian of the projection zone in the Gauss Kruger projection is equal to one-half multiplied by the sum of the minimum and maximum longitudes;

S3.3. Project the index i and index j and the latitude and longitude data between index i and index j into plane coordinates (x, y) through the central meridian.

According to some embodiments of the present application, the curve recognition method based on the latitude and longitude data of inland watercraft, the method for polynomial fitting of the plane coordinates in the step 4 includes:

S4.1. Perform a translation operation on the plane coordinates (x, y) of the central meridian projecting the index i and index j and the latitude and longitude data between index i and index j;

S4.2. Perform polynomial fitting on the plane coordinates (x, y) after the translation operation in four ways: abcd:

a directly performing polynomial fitting on the plane coordinates (x, y) after the translation operation;

b performing polynomial fitting after exchanging the x and y values of the plane coordinates (x, y) after the translation operation;

c. After the plane coordinates (x, y) after the translation operation are rotated 45 degrees to the right along the origin of the coordinates, polynomial fitting is performed;

d Perform polynomial fitting after the plane coordinates (x, y) after the translation operation are rotated 45 degrees to the left along the origin of the coordinates;

S4.3. Calculate the R square of the fitting results of the four methods of abcd, and select the fitting result with the largest R square as the final fitting result. If the largest fitting result in the R square is qualified, proceed to step 5; if the largest fitting result in the R square If the results are all unqualified, perform polynomial fitting in the fifth way:

eStarting from the plane coordinates (x, y) after the translation operation, rotate the coordinate points clockwise with the coordinate origin as the center and in units of 30 degrees to generate 12 sets of plane coordinates in total, and perform polynomial fitting on each set of plane coordinates , get 12 groups of you and the result;

S4.4. Calculate the R square of the 12 sets of fitting results in the e method, and select the fitting result with the largest R square as the final fitting result. If the largest fitting result in the R square is qualified, proceed to step 5; if the largest in the R square If the fitting result is unqualified, the fitting fails, and the largest fitting result among the R squares among the fitting results is selected to proceed to step 5.

According to the curve recognition method based on the latitude and longitude data of inland watercraft in some embodiments of the present application, the step S4.1 specifically includes projecting the index i and index j and the plane coordinates (x, y) of the latitude and longitude data between index i and index j )’s x and y values are all subtracted from the x minimum value and y minimum value in this segment, and then add 10 respectively to make the plane coordinates of this segment move closer to the coordinate origin;

In the step S4.2, the method of rotating the plane coordinates (x, y) after the translation operation by 45 degrees to the right along the origin of the coordinates includes

First convert the Cartesian coordinates (x, y) to polar coordinates (ρ, θ);

Then add π/4 to θ in polar coordinates;

Then the polar coordinates are converted to Cartesian coordinates (x, y) values;

Finally, the x and y values of each coordinate are subtracted from the x minimum value and y minimum value of all coordinates to ensure that all values are positive;

In the step S4.2, the method of rotating the plane coordinates (x, y) after the translation operation by 45 degrees to the left along the origin of the coordinates includes

First convert the Cartesian coordinates (x, y) to polar coordinates (ρ, θ);

Then subtract π/4 from θ in polar coordinates;

Then the polar coordinates are converted to Cartesian coordinates (x, y) values;

Finally, the x and y values of each coordinate are subtracted from the minimum x and y values of all coordinates to ensure that all values are positive.

According to some embodiments of the present application, the curve recognition method based on the latitude and longitude data of inland ships, the fitting result evaluation index uses the R square coefficient of determination, and the R square greater than 0.999 means that the fitting is qualified;

The polynomial fitting is specifically as follows: starting from the fifth-degree polynomial fitting, if the fitting result R square is qualified, then the polynomial fitting is ended; if the fitting result R square is unqualified, then the number of polynomials is increased by one, and the fitting is performed again, and the fitting result R If the square is qualified, it will end; if the polynomial degree increases to 20 and the fitting result R square is still unqualified, the polynomial fitting will be forcibly terminated.

According to some embodiments of the present application, the curve identification method based on the latitude and longitude data of inland ships, in the step 5, according to the index numbers i and j, the method for determining the index numbers k and l includes

When the serial number of the starting index i is equal to 0, it means that this segment is the starting segment, at this time, the serial number of the index k is equal to the serial number of the index i is equal to 0, and the serial number of the index l is equal to i+(j-i)÷3×2;

When the serial number of index j is greater than or equal to N-1, it means that this segment is the end segment. At this time, the serial number of index k is equal to the serial number of index l in the previous iteration, and the serial number of index l in this iteration is equal to N-1;

When the serial number of index i and the serial number of index j do not meet the above two conditions, it means that this segment is an intermediate segment. At this time, the serial number of index k is equal to the serial number of index l in the previous iteration, and the serial number of index l in this iteration It is equal to i+(j-i)÷3×2.

According to some embodiments of the present application, the curve recognition method based on the latitude and longitude data of inland ships, in step 5, according to the plane coordinates of the latitude and longitude data corresponding to the index k and index l and all indexes between index k and index l Radius of curvature, the method for calculating the drop value of inland river ship cornering speed corresponding to the radius of curvature, including

According to the maximum fitting result in the qualified R square in the step step, calculate the radius of curvature of each plane coordinate of the corresponding longitude and latitude data of the index k to the index l;

Calculate the specific value of the speed drop corresponding to the curvature radius through the Felsov speed drop formula, and use this value as the curve mark of the latitude and longitude data corresponding to the plane coordinate point. Among them, the Felsov speed drop formula:

In the formula: V _c is the speed of the ship during the turning process; V ₀ is the initial speed of the ship turning, R is the radius of curvature of turning, and L is the length of the ship.

According to the curve recognition method based on the latitude and longitude data of inland watercraft in some embodiments of the present application, the closer the specific value of the speed drop is to 1, the larger the curvature radius of the curve is, and the closer to a straight line, the smaller the cornering resistance; the smaller the specific value of the speed drop, the smaller the curve. The smaller the radius of curvature of the curve, the greater the cornering resistance, so you need to slow down when cornering.

According to some embodiments of the present application, the curve recognition method based on the longitude and latitude data of inland ships, in step 6, according to the sequence numbers i and j of the index i and index j, the method of re-determining the starting index i includes the method of re-determining the index i in the current iteration and the sequence number of index j, the sequence number of the re-determined starting index i is increased by (j-i)÷3.

Beneficial effect:

In the present invention, segmenting through the longitude difference can ensure that the deformation of the subsequent projection can be controlled in a very small range.

The subdivision strategy of the present invention, which is based on the fixed longitude difference mode and supplemented by the fixed number mode, ensures that a small number of inland river routes in the north-south direction (the direction with small longitude changes) can also be successfully segmented. By adjusting the longitude difference and the maximum and minimum number of segments, it can adapt to navigation data of different collection frequencies and routes with too dense curves.

The present invention uses one-half of the sum of the maximum and minimum values of each segment of longitude as the central meridian to form a local Gauss Kruger projection zone instead of using a standard projection zone, thereby further reducing the deformation of the Gauss Kruger projection.

The present invention carries out polynomial fitting through five methods of abcde, and greatly improves the success rate of polynomial fitting under the premise of ensuring that the route is not deformed.

The present invention greatly improves the operation speed under the premise of ensuring the success rate through a specific polynomial fitting method.

The present invention only calculates the radius of curvature in the middle of each section without considering the two ends, eliminating the special situation that the curve appears at both ends of a certain section, which causes inaccurate fitting and calculation of the radius of curvature.

Additional aspects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

Figure 1 is the basic flow chart.

Figure 2 is the latitude and longitude data map of a certain voyage.

Figure 3 is the route map for the first segment.

Fig. 4 is the projection result map of the latitude and longitude coordinates of the first segment.

Fig. 5 is a graph of the fitting results of the first segment abcd four ways.

Figure 6 is a graph showing the results of marking using the velocity drop value.

Fig. 7 is a route diagram of the curve recognition result.

FIG. 8 is an iterative diagram for determining the specific serial number values of index k and index l and index i.

Detailed ways

The embodiments of the present application are described in detail below with reference to the accompanying drawings. Examples of the embodiments are shown in the accompanying drawings. The present invention proposes a method for identifying waterway bends based on inland waterway ship navigation data. In the method, a certain navigation To obtain the latitude and longitude data, for convenience of explanation, use N to represent the number of latitude and longitude data, and the index of each latitude and longitude data in order is from 0 to N-1. In the present invention, for the index i, it can be understood as the index that the serial number is i, i represents the serial number of index i. According to the latitude and longitude data, the curve recognition method includes the following steps:

Step 1: Segment all the latitude and longitude data in a specific way, and the segmentation result is the latitude and longitude data between index i and index j. In the preferred solution, in step 1, segmentation is performed by mainly using the fixed longitude difference method and supplemented by the fixed number method. Specifically, when the number of segmented data intercepted by the fixed longitude difference method is too large or too small, it is automatically converted to a fixed number of segmented data. Among them, the curve characteristics of the route are represented by the size and density of the curve in the route. The smaller the curve is, the denser it is, the value of the longitude difference should be appropriately reduced, and the value of the maximum and minimum numbers should be appropriately reduced at the same time to ensure that the intercepted section There will not be too many bends to cause polynomial fitting; the higher the collection frequency of latitude and longitude data, the shorter the actual length of a section of the route intercepted under the same number, and the value of the maximum and minimum numbers should be increased appropriately at the same time to Ensure that the actual length of the intercepted section of the route does not change much; the smaller the Gauss Kruger projection deformation is required, the lower the value of the longitude difference, and vice versa. In the preferred scheme, the longitude difference of each segment is set to be 0.1 degrees, and the minimum fixed number is set to 33, and the maximum is 99. It is understandable that the set parameters can be deformed according to the latitude and longitude data of different acquisition frequencies and the Gauss Kruger projection Appropriate adjustments are required.

Firstly, each piece of longitude and latitude data is intercepted by a fixed longitude difference. Segmentation starts from the latitude and longitude data of the i-th index, and the serial number of the index j increases from the i+1th, and every time one is added, the difference between the minimum longitude and the maximum longitude of all data between index i and index j is checked. If the longitude difference is greater than 0.1 degrees, the serial number j of the index j stops increasing. At this time, if j-i is less than 33, force j=i+33, and if j-i is greater than 33, no operation is performed. If the difference in longitude is not greater than 0.1 degrees, the serial number j of index j continues to increase until the longitude difference requirement is met. If the sequence number j of the index j increases beyond i+99 and still fails to meet the longitude difference requirement, the sequence number j of the index j stops increasing and j=i+99 is forced. Finally, through the remainder of (j-i)÷3, the serial number j of index j is increased or decreased by one or remains unchanged, ensuring that (j-i) is divisible by 3, and the segment ends and step 2 begins.

Step 2: Project the longitude and latitude data between index i to j into plane coordinates by Gauss Kruger projection method, and the plane coordinates are the same as the index of the corresponding longitude and latitude data. In the preferred solution, the specific content of step 2 includes extracting the minimum longitude and maximum longitude of all latitude and longitude data between index i and index j after step 1 is segmented, and in the Gauss Kruger projection, the central meridian of the projection zone It is equal to one-half times the sum of the minimum and maximum longitudes. Then project the longitude and latitude data between index i to index j as plane coordinates (x, y) through the central meridian.

Step 3: Carry out polynomial fitting to the plane coordinates in a specific way. In the preferred version, the specific content of said step 3 includes:

Firstly, translate a segment of plane coordinates (x, y) output in step 2: subtract the minimum value of x and minimum value of y in the segment from the x and y values of all coordinates, and then add 10 to make the entire segment The plane coordinates move closer to the origin of the coordinates, which is beneficial to the polynomial fitting effect. The fitting result evaluation index uses the R square coefficient of determination, and the R square greater than 0.999 indicates that the fitting is qualified.

Then polynomial fitting is performed in four ways of abcd:

a. Directly perform polynomial fitting according to the original plane coordinates (x, y);

B. carry out polynomial fitting after the value interchange (that is mirror image along straight line y=x) of whole section x and y;

c. After rotating the entire original plane coordinates (x, y) 45 degrees to the right along the origin of the coordinates, polynomial fitting is performed;

d. After rotating the entire segment of the original plane coordinates (x, y) 45 degrees to the left along the origin of the coordinates, perform polynomial fitting.

The specific operation of plane coordinate rotation is: first convert the Cartesian coordinate (x, y) value to polar coordinate (ρ, θ), then add or subtract π/4 to θ in the polar coordinate, and then convert the polar coordinate to Cartesian Coordinates (x, y) value, the x and y values of each coordinate are subtracted from the x minimum value and y minimum value of all coordinates, and 10 is added to each of them to ensure that all values are positive.

The specific method of polynomial fitting is as follows: start from 5th degree polynomial fitting, if the fitting result R square is qualified, then end the polynomial fitting; if the fitting result R square is unqualified, add one to the polynomial degree, fit again, and the fitting result R square If it is qualified, it will end; if the degree of polynomial increases to 20 and the fitting result R square is still unqualified, the polynomial fitting will be forcibly terminated. It can be understood that, for any polynomial fitting of a to e, the specific polynomial fitting method can be used.

Then calculate the R square of the fitting results of the four methods of abcd, select the fitting result with the largest R square as the final fitting result, and start step 4 if the largest R square is qualified. If the R square of the fitting results of the four methods is unqualified, an additional fifth e-mode polynomial fitting is performed:

e. Starting from the original plane coordinates (x, y), rotate the coordinate points clockwise by 30 degrees to generate 12 sets of plane coordinates, and perform polynomial fitting on each set of plane coordinates.

Finally, calculate the R square of the 12 sets of fitting results in the e method, select the fitting result with the largest R square as the final fitting result, and start step 4 if the largest R square is qualified. If the maximum R square is still unqualified, the best fitting result graph will be printed out and "fitting failure" will be prompted. Therefore, in this scheme, you can choose the largest fitting result in the R square in the fitting result to proceed to the step 5.

Step 4: Calculate the curvature radius of the plane coordinates of a specific part (index k to index l) through the fitting result curve, and use the inland river ship cornering speed drop corresponding to the curvature radius as a mark. As a preferred solution, the step 4 divides each section (index i to j) into three parts on average in order to prevent the curve from appearing at both ends of a certain section (index i to j) and cause inaccurate fitting and curvature radius calculation. Parts, only the radius of curvature of the middle part (index k to l) is calculated. However, since each segment is segmented using the strategy of longitude difference segmenting as the main method and the number segmenting method as the supplementary method, the length of each segment may be different, and the calculation of the radius of curvature for some longitudes and latitudes may be skipped. Therefore, the step 4 specifically determines that the specific sequence number values of the indexes k and l are determined by the following method:

When the serial number i of the index i is equal to 0, it means that this segment is the initial segment. At this time, the serial number of the index k is equal to i equal to 0, and the serial number of the index l is equal to i+(j-i)÷3×2.

When the serial number of index j is greater than or equal to N-1, it means that this segment is the end segment. At this time, the serial number of index k is equal to the serial number of index l last time, and the serial number of index l this time is equal to N-1.

When the serial numbers of index i and index j do not meet the above two conditions, it means that this segment is an intermediate segment. At this time, the serial number of index k is equal to the serial number of index l last time, and the serial number of index l this time is equal to i+(j-i )÷3×2.

Since the radius of curvature is only calculated for the middle part of a segment each time, the serial number i of the index i before each segment is iteratively calculated by the following formula:

The determination of the specific serial number values of index k and index l and the iteration of index i are shown in Figure 8. According to Figure 8, the present invention determines the specific serial number values of index k and index l as follows:

1. Only the middle part is calculated to eliminate the problem of inaccurate fitting and curvature radius calculation caused by the appearance of curves at both ends of a certain section.

2. (Assuming that the number of each segment is equal) Since only the middle part is calculated, only 1/3 of the steps can be advanced to ensure that the middle part of this time and the middle part of the previous time are connected in serial number.

3. Since the number of segments is different each time, the middle segment cannot be connected again, so the method that this time k is equal to the previous l is forced to connect.

According to the design idea, the present invention uses the strategy of assigning different index serial numbers under different segmentation conditions, cooperates with the iterative assignment of index serial numbers, and uses the assignment that the serial number of index l is equal to i+(j-i)÷3×2 way, the purpose is to cooperate so that under the segmentation strategy adopted by the present invention, each segment is divided into three parts, and when each iteration is segmented, the way forward is to increase the sequence number of index i by (j-i)÷3, where In this way, the segment of this iteration and the segment of the last iteration can have overlapping parts (for example, about the last 2/3 of the previous segment and the first 2/3 of the next segment are overlapped), Thus after each iteration only the radius of curvature of the middle part of the segment (indices k to l) is calculated for the current segment.

Under such a technical solution, the problem of inaccurate fitting and calculation of the radius of curvature caused by the bend appearing at both ends of a certain section can be solved as much as possible. After each iteration, the serial number of the index k is equal to the serial number of the previous index l. Under such a technical solution, it can be solved as much as possible in the present invention. , resulting in the problem that the length of each segment may be different, and the calculation of the radius of curvature of some latitude and longitude may be skipped.

Calculate the radius of curvature of each plane coordinate between index k and index l determined in step 4 through the curve fitting result in step 3. Then, the specific value of the speed drop corresponding to the radius of curvature is calculated by the following Felsoff speed drop formula. And use this specific value as the curve mark of the latitude and longitude data corresponding to the plane coordinate point. The larger the value, the closer to 1, the larger the curvature radius of the curve, the closer to the straight line, and the smaller the cornering resistance; the smaller the value, the smaller the curvature radius of the curve , the greater the cornering resistance, the need to decelerate to corner.

Felsoff speed drop formula:

In the formula: V _c is the speed of the ship during the turning process; V ₀ is the initial speed of the ship turning; R is the radius of curvature of turning, and L is the length of the ship.

After marking, determine the specific serial number value of index i before the next segment through the iterative method of index i in step 4, and then repeat steps 1-5 until the curve marking of all latitude and longitude data is completed.

Step 5: Start the second segment after advancing a specific amount of latitude and longitude data, repeat steps 1-4, and so on, until the entire navigation data curve identification is completed. As a preferred solution, the specific content of step 5 is: the specific number is equal to (j-i)÷3, and the way forward is to increase the serial number of index i by (j-i)÷3, and then repeat step 1 to segment again. Then repeat the subsequent steps in sequence until the curve recognition of all the latitude and longitude data is completed.

Wherein, the specific number is equal to (j-i)÷3, as mentioned above, the serial number i of the index i is iteratively calculated by the following formula:

In a specific example, as shown in Figure 1, on the basis of the above-mentioned curve recognition method, the curve recognition method of the present invention is based on a total of 2936 longitude and latitude data obtained by a certain voyage, as shown in Figure 2, according to The sequence index from 0 to 2935 is taken as an example to further illustrate the curve recognition method of the present invention. The recognition method specifically includes:

Step 1: Carry out segmentation by using the fixed longitude difference method as the main method and the fixed number method as the auxiliary method. Specifically, when the number of segmented data intercepted by the fixed longitude difference method is too large or too small, it is automatically converted to a fixed number of segmented data. The longitude difference of each section is set to 0.1 degrees, and the fixed number is set to a minimum of 33 and a maximum of 99. The setting parameters can be adjusted appropriately according to the latitude and longitude data of different collection frequencies and the Gauss Krüger projection deformation requirements.

Firstly, each piece of longitude and latitude data is intercepted by a fixed longitude difference. The first segment starts from the latitude and longitude data corresponding to the index i, where the serial number i of the index i=0, and the serial number j of the index j increases from i+1, each time one is added, check the minimum value of all data between the index i and the index j The difference between the longitude and the maximum longitude. When the serial number j of the index j increases to 78, the longitude difference is greater than 0.1 degrees, and the serial number j stops increasing. At this time, j-i=77, which is greater than 33. If the longitude difference is still less than 0.1 when the sequence number j of the index j is increased beyond i+99, the sequence number j stops increasing and the sequence number j=i+99 is forced. Finally, through the remainder of (j-i)÷3, the serial number j is increased or decreased by one or remains the same, ensuring that (j-i) can be divisible by 3, (j-i)÷3=1, j=77+1=78, divided end of segment. The result of the first segment is i=0, j=78, and the route of the first segment is shown in FIG. 3 .

Step 2: Extract the minimum longitude and maximum longitude of all latitude and longitude data between index i=0 and index j=78 after segmenting in step 1, and then take half of the sum of the minimum and maximum longitude as the Gauss Kruger projection zone , and then project the longitude and latitude data from index i=0 to index j=78 into plane coordinates (x, y). The projection results of the first segment of latitude and longitude coordinates are shown in Figure 4.

Step 3: Carry out polynomial fitting to the plane coordinates in a specific way. Firstly, translate a segment of plane coordinates (x, y) projected in step 2: subtract the minimum value of x and minimum value of y in the segment from the x and y values of all coordinates, and then add 10 to each, so that the whole The segment plane coordinates move closer to the coordinate origin. The fitting result evaluation index uses the R square coefficient of determination, and the R square greater than 0.999 indicates that the fitting is qualified.

Then polynomial fitting is performed in four ways of abcd:

a. Directly perform polynomial fitting according to the original plane coordinates (x, y);

B. carry out polynomial fitting after the value interchange (that is mirror image along straight line y=x) of whole section x and y;

c. After rotating the entire original plane coordinates (x, y) 45 degrees to the right along the origin of the coordinates, polynomial fitting is performed;

d. After rotating the entire segment of the original plane coordinates (x, y) 45 degrees to the left along the origin of the coordinates, perform polynomial fitting.

The fitting results of the four ways of abcd in the first segment are shown in Figure 5.

Then calculate the R square of the fitting results of the four ways of abcd, which are R square_a=0.9861, R square_b=0.9564, R square_c=0.9957, R square_d=0.9999. Among them, R squared_d is the largest, so the fitting result of d is selected as the final fitting result. Obviously, at this time, R squared_d>0.999 is qualified, and step 4 can be started. If the largest R-square <0.999 is still unqualified, an additional fifth e-mode polynomial fit is performed:

e. Starting from the original plane coordinates (x, y), rotate the coordinate points clockwise by 30 degrees to generate 12 sets of plane coordinates, and perform polynomial fitting on each set of plane coordinates.

Finally, calculate the R square of the 12 sets of fitting results in the e method, select the fitting result with the largest R square as the final fitting result, and start step 4 if the largest R square is qualified. If the maximum R square is still unqualified, the best fitting result graph will be printed out and "fitting failure" will be prompted.

Step 4: Calculate the curvature radius of the plane coordinates of a specific part (index k to index l) through the fitting result curve, and use the inland river ship cornering speed drop corresponding to the curvature radius as a mark. First, determine the specific serial number values of the specific part index k and index l according to three situations: when the serial number of the index i is equal to 0, it means that this segment is the starting segment, at this time the serial number of the index k is equal to the serial number i is equal to 0, and the serial number of the index l The serial number is equal to i+(j-i)÷3×2. When the sequence number of index j is greater than or equal to N-1, it means that this segment is the end segment. At this time, the sequence number of index k is equal to the sequence number of index l last time, and the sequence number of index l this time is equal to N. When the serial number i and the serial number j of the index do not meet the above two conditions, it means that this segment is an intermediate segment. At this time, the serial number of the index k is equal to the serial number of the last index l, and the serial number of the index l this time is equal to i+(j-i )÷3×2. At this time, the serial number i=0 of index i and the serial number j=78 of index j satisfy the first condition, so the serial number k of index k=0 and the serial number of index l=i+(j-i)/3*2=52.

Then, the curvature radius of each plane coordinate corresponding to the part of the longitude and latitude data corresponding to index k to index l is calculated based on the fitted curve result in step 3. Finally, the following Felsoff velocity drop formula is adopted:

Combined with the length of the ship L=189.9m and the radius of curvature corresponding to each coordinate, calculate the specific value of the corresponding speed drop. At the same time, use this value as the curve mark of the latitude and longitude data corresponding to the plane coordinate point, and the marking result is shown in Figure 6. The larger the value, the closer to 1, the larger the curvature radius of the curve, the closer to the straight line, and the smaller the cornering resistance; the smaller the value, the smaller the curvature radius of the curve, the greater the cornering resistance, and you need to slow down to corner.

Step 5: advance the serial number i of the index i, after advancing (j-i)÷3=26 latitude and longitude data, start the second segment from i=26, repeat steps 1-4, and so on, until the entire voyage is completed Data curve recognition. If the latitude and longitude coordinates marked with a speed drop value less than 0.99 are identified as curves, the route map of the curve recognition results is shown in Figure 7.

According to the solution, the present invention can ensure that the deformation of the subsequent Gauss-Krüger projection can be controlled in a very small range by segmenting through the longitude difference. Because the degree of deformation of the Gauss Kruger projection is only related to the longitude difference between the point and the central meridian, setting the longitude difference of each segment controls the maximum deformation of each segment of the Gauss Kruger projection. The subdivision strategy of the present invention, which is based on the fixed longitude difference mode and supplemented by the fixed number mode, ensures that a small number of inland river routes in the north-south direction (the direction with small longitude changes) can also be successfully segmented. By adjusting the longitude difference and the maximum and minimum number of segments, it can adapt to navigation data of different collection frequencies and routes with too dense curves.

According to the scheme, the present invention uses half of the sum of the maximum and minimum values of each segment of longitude as the central meridian to form a local Gauss Kruger projection zone instead of using a standard projection zone, which further reduces the Gauss Kruger projection. deformation.

According to the scheme, the present invention performs polynomial fitting in five ways of abcde, and greatly improves the success rate of polynomial fitting on the premise of ensuring that the route is not deformed.

According to the solution, the present invention greatly improves the calculation speed under the premise of ensuring the success rate through a specific polynomial fitting method.

According to the solution, the present invention only calculates the radius of curvature of the middle portion of each section without considering the two ends, eliminating the special situation that the curve appears at both ends of a certain section, which causes inaccurate fitting and calculation of the radius of curvature.

As used herein, the terms "one embodiment," "some embodiments," "example," "specific examples," or "some examples" mean specific features, structures, materials, or features described in connection with the embodiment or example. A feature is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the described specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples and features of different embodiments or examples described in this specification without conflicting with each other.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope of the disclosure of the present invention, according to the present invention Any equivalent replacement or change of the created technical solution and its inventive concept shall be covered within the scope of protection of the present invention.

Claims (10)

1. A method for identifying curves based on latitude and longitude data of inland ships, characterized in that, comprising Step 1: Set the index of obtaining N sequential latitude and longitude data through navigation from 0 to N-1; Step 2: Segment the latitude and longitude data according to the latitude and longitude data of the starting index i, and the segmentation result includes the latitude and longitude data corresponding to index i and index j and all indexes between index i and index j; Step 3: Project the latitude and longitude data corresponding to index i and index j and all indexes between index i and index j into plane coordinates, and the index of plane coordinates is the same as the index of latitude and longitude data; Step 4: Carry out polynomial fitting to described plane coordinate; Step 5: According to the serial numbers i and j of the index i and the index j, determine the index serial numbers k and l; through the polynomial fitting result of the plane coordinates, calculate the index k and the index l and all between the index k and the index l The radius of curvature of the plane coordinates of the latitude and longitude data corresponding to the index; According to the radius of curvature of the plane coordinates of the longitude and latitude data corresponding to the index k and the index l and all indexes between the index k and the index l, calculate the inland river ship cornering speed drop value corresponding to the curvature radius; Mark the curves of the longitude and latitude data corresponding to index k and index l and all indexes between index k and index l according to the drop value of the inland waterway ship's cornering speed; Step 6: re-determine the starting index i according to the serial numbers i and j of the index i and the index j, and the marking serial number of the re-determined starting index is greater than the marking serial number of the starting index; Step 7: Repeat Step 2-Step 6 until the curve marking of all the latitude and longitude data is completed. 2. The curve recognition method based on inland waterway ship latitude and longitude data according to claim 1, characterized in that, the segmented method of the step 2 includes Starting from the latitude and longitude data of the starting index i, the serial number of the index j increases from i+1, and every time one is added, check the difference between the minimum longitude and the maximum longitude of the latitude and longitude data corresponding to all the indexes from index i to index j, where, The value of the difference between the minimum longitude and the maximum longitude is set to x, the minimum value of the fixed number is y, and the maximum value of the fixed number is z; S2.1. If the difference between the minimum longitude and the maximum longitude is greater than x degrees, the serial number of index j stops increasing. At this time, if j-i is less than y, then the serial number j=i+y, if j-i is greater than y then No operation, get the serial number of index j; If the difference between the minimum longitude and the maximum longitude is not greater than x degrees, then the sequence number of index j continues to increase until the difference between the minimum longitude and maximum longitude is greater than x degrees, then the sequence number of index j stops increasing. If j -i is less than y, then the sequence number j=i+y, if j-i is greater than y, no operation is performed, and the sequence number of index j is obtained; If the serial number of the index j increases to exceed i+z and still does not meet the requirement that the difference between the minimum longitude and the maximum longitude is greater than x degrees, the serial number of the index j stops increasing and the serial number j=i+z, and the serial number of the index j is obtained; S2.2. For the calculation of the sequence number of the obtained index j and the sequence number of the starting index i, through the remainder of (j-i)÷3, the sequence number j is increased or decreased by one or unchanged, so that (j-i) It can be divisible by 3 to obtain the serial number of the final index j, so as to obtain the longitude and latitude data corresponding to all indexes including index i and index j and between index i and index j. 3. The curve identification method based on the latitude and longitude data of inland watercraft according to claim 1, wherein in said step 3, the latitude and longitude corresponding to all indexes between index i and index j and index i and index j Methods for projecting data into planar coordinates, including S3.1. After extracting the segmented index i and index j and the minimum longitude and maximum longitude among all the longitude and latitude data between index i and index j; S3.2. The central meridian of the projection zone in the Gauss Kruger projection is equal to one-half multiplied by the sum of the minimum and maximum longitudes; S3.3. Project the index i and index j and the latitude and longitude data between index i and index j into plane coordinates (x, y) through the central meridian. 4. The curve recognition method based on the latitude and longitude data of inland ships according to claim 1, wherein the method for polynomial fitting of the plane coordinates in the step 4 includes S4.1. Perform a translation operation on the plane coordinates (x, y) of the central meridian projecting the index i and index j and the latitude and longitude data between index i and index j; S4.2. Perform polynomial fitting on the plane coordinates (x, y) after the translation operation in four ways: abcd: a directly performing polynomial fitting on the plane coordinates (x, y) after the translation operation; b performing polynomial fitting after exchanging the x and y values of the plane coordinates (x, y) after the translation operation; c. After the plane coordinates (x, y) after the translation operation are rotated 45 degrees to the right along the origin of the coordinates, polynomial fitting is performed; d Perform polynomial fitting after the plane coordinates (x, y) after the translation operation are rotated 45 degrees to the left along the origin of the coordinates; S4.3. Calculate the R square of the fitting results of the four methods of abcd, and select the fitting result with the largest R square as the final fitting result. If the largest fitting result in the R square is qualified, proceed to step 5; if the largest fitting result in the R square If the results are all unqualified, perform polynomial fitting in the fifth way: eStarting from the plane coordinates (x, y) after the translation operation, rotate the coordinate points clockwise with the coordinate origin as the center and in units of 30 degrees to generate 12 sets of plane coordinates in total, and perform polynomial fitting on each set of plane coordinates , get 12 groups of you and the result; S4.4. Calculate the R square of the 12 sets of fitting results in the e method, and select the fitting result with the largest R square as the final fitting result. If the largest fitting result in the R square is qualified, proceed to step 5; if the largest in the R square If the fitting result is unqualified, the fitting fails, and the largest fitting result among the R squares among the fitting results is selected to proceed to step 5. 5. The curve identification method based on the latitude and longitude data of inland watercraft according to claim 4, wherein said step S4.1 specifically includes the process of projecting the latitude and longitude data between index i and index j and index i and index j The x and y values of the plane coordinates (x, y) are both subtracted from the x minimum value and y minimum value in this segment, and then add 10 to each, so that the plane coordinates of this segment move closer to the coordinate origin; In the step S4.2, the method of rotating the plane coordinates (x, y) after the translation operation by 45 degrees to the right along the origin of the coordinates includes First convert the Cartesian coordinates (x, y) to polar coordinates (ρ, θ); Then add π/4 to θ in polar coordinates; Then the polar coordinates are converted to Cartesian coordinates (x, y) values; Finally, the x and y values of each coordinate are subtracted from the x minimum value and y minimum value of all coordinates to ensure that all values are positive; In the step S4.2, the method of rotating the plane coordinates (x, y) after the translation operation by 45 degrees to the left along the origin of the coordinates includes First convert the Cartesian coordinates (x, y) to polar coordinates (ρ, θ); Then subtract π/4 from θ in polar coordinates; Then the polar coordinates are converted to Cartesian coordinates (x, y) values; Finally, the x and y values of each coordinate are subtracted from the minimum x and y values of all coordinates to ensure that all values are positive. 6. The curve recognition method based on the latitude and longitude data of inland watercraft according to claim 4, characterized in that the fitting result evaluation index uses the R square coefficient of determination, and the R square is greater than 0.999 to represent that the fitting is qualified; The polynomial fitting is specifically as follows: starting from the fifth-degree polynomial fitting, if the fitting result R square is qualified, then the polynomial fitting is ended; if the fitting result R square is unqualified, then the number of polynomials is increased by one, and the fitting is performed again, and the fitting result R If the square is qualified, it will end; if the polynomial degree increases to 20 and the fitting result R square is still unqualified, the polynomial fitting will be forcibly terminated. 7. The curve identification method based on the latitude and longitude data of inland ships according to claim 1, wherein, in the step 5, according to the index numbers i and j, the method for determining the index numbers k and l comprises When the serial number of the starting index i is equal to 0, it means that this segment is the starting segment, at this time, the serial number of the index k is equal to the serial number of the index i is equal to 0, and the serial number of the index l is equal to i+(j-i)÷3×2; When the serial number of index j is greater than or equal to N-1, it means that this segment is the end segment. At this time, the serial number of index k is equal to the serial number of index l in the previous iteration, and the serial number of index l in this iteration is equal to N-1; When the serial number of index i and the serial number of index j do not meet the above two conditions, it means that this segment is an intermediate segment. At this time, the serial number of index k is equal to the serial number of index l in the previous iteration, and the serial number of index l in this iteration It is equal to i+(j-i)÷3×2. 8. The curve recognition method based on the longitude and latitude data of inland watercraft according to claim 7, wherein in said step step 5, according to the index k and index l and the index k and index l corresponding to all indexes between the index k and index l The radius of curvature of the plane coordinates of the latitude and longitude data, and the method of calculating the drop value of the inland waterway ship’s cornering speed corresponding to the radius of curvature, including According to the maximum fitting result in the qualified R square in the step step, calculate the radius of curvature of each plane coordinate of the corresponding longitude and latitude data of the index k to the index l; Calculate the specific value of the speed drop corresponding to the curvature radius through the Felsov speed drop formula, and use this value as the curve mark of the latitude and longitude data corresponding to the plane coordinate point. Among them, the Felsov speed drop formula:

In the formula: V _c is the speed of the ship during the turning process; V ₀ is the initial speed of the ship turning, R is the radius of curvature of turning, and L is the length of the ship. 9. The curve recognition method based on the longitude and latitude data of inland ships according to claim 8, wherein the closer the specific numerical value of the speed drop is to 1, the larger the radius of curvature of the curve is, and the closer to a straight line, the smaller the cornering resistance; The smaller the specific value of the drop, the smaller the radius of curvature of the curve, and the greater the resistance to cornering, so you need to slow down when cornering. 10. The curve identification method based on the longitude and latitude data of inland ships according to claim 7, wherein, in step 6, according to the serial numbers i and j of the index i and the index j, the method for re-determining the initial index i includes passing For the sequence number calculation of index i and index j in the current iteration, the sequence number of the re-determined starting index i is incremented by (j-i)÷3.

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