A sextant simulator-based virtual training system for ship positioning

Abstract

The application discloses a kind of ship positioning virtual training system based on sextant simulator, including for obtaining 3D modeling reproduction module, the data setting module of setting virtual positioning practice data, the simulation scene construction module of setting sea virtual training scene, interactive training module and the positioning model construction module of obtaining celestial positioning model and landmark positioning model;Comprehensive evaluation storage module is used to obtain the result data of each operation training stage and operation level score, and based on the result data of each operation training stage, according to the constructed celestial positioning model or landmark positioning model, the virtual training result of ship navigation positioning is obtained.The application solves the problem that the traditional operation training usually relies on actual ship training, but there are certain limitations and problems, due to the high cost of real ship training, great safety risk and the reason that complex marine environment cannot be truly reproduced, it is difficult to provide diversified and flexible operation training scene, so that the crew cannot effectively understand and master the ship positioning principle and skill experience under various complex marine environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of navigation and positioning of marine vessels, and in particular to a virtual training system for positioning of marine vessels based on a sextant simulator. BACKGROUND

[0002] High-precision navigation and positioning of marine vessels helps the duty officer to keep abreast of the navigation environment of the vessel and supervise the execution of the route. With the development of modern technology, navigation technologies such as GPS provide support for navigation and positioning of marine vessels.

[0003] However, in the absence of electronic systems and satellite signals and other equipment, or when the management and maintenance of some equipment are not in place, or in a complex electromagnetic environment, the navigation and positioning of marine vessels cannot be accurately and efficiently achieved due to excessive reliance on satellite navigation. Therefore, in the process of training of crew members, it is particularly important for the crew members to understand the principles and experiences of positioning of marine vessels in different sea conditions when satellite navigation fails. Traditional operation training usually relies on actual ship training, but there are certain limitations and problems. Due to high cost, great safety risk and inability to truly reproduce complex navigation environment, it is difficult to provide diversified and flexible operation training scenarios, so that the crew members cannot effectively understand and master the principles and experience of positioning of marine vessels in various complex navigation environments. SUMMARY

[0004] The present application provides a virtual training system for positioning of marine vessels based on a sextant simulator to overcome the above technical problems.

[0005] To achieve the above-mentioned purpose, the technical solution of the present application is as follows:

[0006] A virtual training system for positioning of marine vessels based on a sextant simulator, comprising a 3D modeling reproduction module for obtaining the structure of a sextant simulator,

[0007] a data setting module for setting virtual positioning practice data,

[0008] a simulation scene construction module for setting a virtual training scene at sea according to the virtual positioning practice data, a virtual interactive training module for performing astronomical positioning virtual training and landmark positioning virtual training based on the sextant simulator structure obtained by the 3D modeling reproduction module according to the virtual training scene at sea;

[0009] a positioning model construction module for obtaining an astronomical positioning model and a landmark positioning model;

[0010] The data setting module comprises a script editing setting module for setting astronomical positioning training data and landmark positioning training data based on the positioning model construction module, a stage operation scoring module and a comprehensive evaluation storage module;

[0011] The script editing and setting module is used to set script data for virtual positioning exercises of navigation and positioning of marine vessels through a preset editing interface, and to set sub-script data for several operation training stages in the script data according to the training type of the virtual positioning exercise.

[0012] Furthermore, the sub-script data is used to characterize each operation training stage in the corresponding script data during virtual positioning practice;

[0013] The operation training phase includes at least the following phases: the image motion simulation training phase for the sextant moving mirror inspection and correction function, the image motion simulation training phase for the sextant fixed mirror inspection and correction function, the sextant index difference measurement simulation training phase, and the sextant celestial altitude measurement simulation training phase.

[0014] The stage operation scoring module is used to obtain the result data of the virtual interactive training and, based on the preset operation standard threshold, to score the operation level of the result data of the training operation in each operation training stage.

[0015] The operation level is a score threshold obtained by manually dividing the operation standard threshold.

[0016] The comprehensive evaluation and storage module is used to acquire the result data and operation level scores of each operation training stage, and based on the result data of each operation training stage, obtain the virtual training results of ship navigation and positioning according to the constructed astronomical positioning model or land landmark positioning model.

[0017] Based on the error tolerance difference between the virtual training results and the actual ship navigation and positioning results, it is determined whether the virtual training of the trainees has met the standards. Based on the operation level score, the operation training stage that does not meet the virtual training requirements is identified, so as to carry out targeted simulation training.

[0018] Furthermore, the method for the positioning model construction module to obtain the astronomical positioning model specifically includes the following steps:

[0019] S01: Construct a celestial orientation mathematical model to obtain celestial data in real time through the celestial orientation mathematical model; and the celestial data includes celestial altitude and celestial orientation;

[0020] To dynamically simulate and obtain the dynamic orientation of celestial bodies through celestial models;

[0021] S02: Based on the sextant measurement method, measurement data is obtained according to the dynamic orientation of celestial bodies;

[0022] The measurement data includes at least the measurement data of celestial altitude and index difference;

[0023] Furthermore, the measured data of the index difference is the celestial body time angle deviation;

[0024] Based on celestial altitude data and index difference measurement data, virtual ship position lines are drawn and obtained in conjunction with ship navigation scenarios to determine the ship position of the preset virtual ship. The error triangle method is then used to optimize the virtual ship position to obtain an astronomical positioning model.

[0025] Furthermore, the method for constructing the mathematical model of celestial orientation in S01 is as follows:

[0026] S011: Construct a mathematical model for the Julian Day, and calculate and obtain the Julian Day parameter J based on the input year / month / day and UTC. Its expression is:

[0027]

[0028] In the formula: year represents the input year of the Julian Day mathematical model; month represents the input month of the Julian Day mathematical model; date represents the input day of the Julian Day mathematical model; CMT represents the input UTC of the Julian Day mathematical model;

[0029] S012: Based on the Julian sun parameter J and the simulation time of the virtual sextant simulator, obtain the declination Dec and local time angle LHA of the celestial body. Their expressions are as follows:

[0030]

[0031] In the formula: M represents the standard meridian of the simulated time zone; t s Indicates the simulation time of the simulation scenario;

[0032] S013: Based on the declination Dec and local time angle LHA of a celestial body, construct a method for calculating the altitude h of the celestial body. c With celestial position A c The mathematical model of celestial orientation is expressed as follows:

[0033]

[0034] Furthermore, S02 specifically includes the following steps:

[0035] S021: Based on the sextant measurement method, measurement data is obtained according to the dynamic orientation of celestial bodies;

[0036] Based on the celestial altitude data and the index difference measurement data, the true altitude h of the celestial body is obtained. t And the corresponding celestial local time angle LHA1; its expression is:

[0037] h t =h0+d+p1+p2

[0038]

[0039] In the formula: GHA represents the Green's time angle of the observed celestial body; ms represents the basic variable of the Green's time angle; v represents the time angle deviation; p1 represents the longitude of the virtual ship's environment; p2 represents the celestial body altitude correction; p0 represents the solar additional correction parameter; h0 represents the celestial body altitude measured by manipulating the sextant; d represents the eye height difference.

[0040] S022: Based on the local time angle LHA1 of the celestial body, obtain the declination Dec of the geographical location point b corresponding to the observed celestial body position B according to step S13;

[0041] S023: Based on the zenith position of the virtual ship (Z) c The celestial position B and the Earth's pole P N Draw an astronomical triangle for the vertices and project it onto the Earth's surface to obtain the projected triangle cbp. n ;

[0042] With geographical point b as the center and the true altitude h of the celestial body t Draw the ship position curve II with radius , and intersect the ship position curve II with the projected triangle cbp. n The intersection point k is the tangent point Ⅱ-Ⅱ of the ship position curve II, which is the ship position line;

[0043] S024: Confirm the number of celestial bodies involved in the ship's navigation and positioning, and the number of celestial bodies includes at least two or three;

[0044] If it is confirmed that there are two celestial bodies, then two ship position lines are obtained based on step S023, and the intersection of the two ship position lines is taken as the ship position of the preset virtual ship. Its expression is

[0045]

[0046] Z 1,2 =90°-h t1,2

[0047] In the formula: Z 1,2 Indicates intermediate parameter variables; h t1,2 Indicates the true altitude of the corresponding two celestial bodies;

[0048] If the number of celestial bodies is confirmed to be three, then three ship position lines are obtained based on step S023, and the intersection of the three ship position lines is used as the vertex to obtain the ship area positioning triangle.

[0049] The error triangle method is used to optimize the ship's regional positioning triangle. This involves obtaining the angle bisectors of the three angles of the ship's regional positioning triangle and using the intersection of the angle bisectors as the ship's position for the preset virtual ship. Its expression is

[0050]

[0051] In the formula: R represents the Earth's radius; d i,j Let i represent the spherical distance between any two vertices, where i,j = 1, 2, 3.

[0052] Furthermore, the method for the positioning model construction module to obtain the landmark positioning model specifically includes the following steps:

[0053] S001: Determine the number and height of the targets used for ship positioning;

[0054] The number of objects includes at least two or three;

[0055] S002: If the number of targets is confirmed to be two, obtain the known target height H using the sextant simulator obtained from the 3D modeling and reproduction module. i object M i vertical angle α i And according to the vertical angle α i With the height H of the object i Obtain the virtual ship landmark measurement distance D i , i = 1, 2;

[0056] The virtual ship landmark measurement distance D i The expression is

[0057]

[0058] S003: The virtual azimuth angle of the target is obtained by measuring the virtual azimuth angle of the target with the measurement error ΔC set according to the empirical value, and the true azimuth angle TB of the target is obtained by summing the virtual azimuth angle of the target with the measurement error ΔC set according to the empirical value.

[0059] Two bearing lines are drawn along the TB±180° direction, and the intersection of the two bearing lines is taken as the pre-defined virtual ship's position, expressed as follows:

[0060]

[0061] In the formula: M1(x1,y1) and M2(x2,y2) represent the position coordinates of the two objects respectively; e represents the eccentricity of the elliptical meridian; D1 and D2 represent the measured distances from the virtual ship to the two objects respectively; A, B, and C represent intermediate parameters.

[0062] S004: If the number of targets is confirmed to be three, obtain the known target height H using the sextant simulator obtained from the 3D modeling and reproduction module. i object M i vertical angle α i And according to the vertical angle α i With the height H of the object iObtain the virtual ship landmark measurement distance D i i = 1, 2, 3;

[0063] S005: The virtual azimuth angle of the object is obtained by measuring the virtual azimuth angle of the object using a sextant simulator, and the true azimuth angle TB of the object is obtained by summing the virtual azimuth angle of the object with the measurement error ΔC.

[0064] Three azimuth lines are drawn along the TB±180° direction, and the intersection of the three azimuth lines is used as the vertex to obtain the ship's regional positioning triangle;

[0065] S006: The position of the preset virtual ship is determined using the center-of-gravity method based on the ship's regional positioning triangle. The expression is as follows:

[0066]

[0067]

[0068] In the formula: x 12 y 12 x 13 y 13 x 23 y 23 The coordinates of the vertices of the ship's area positioning triangle are represented; M1(x1,y1), M2(x2,y2), and M3(x3,y3) represent the position coordinates of the three landmarks, respectively; θ mi M represents the observation angle between the sextant simulator and each object, where i = 1, 2, 3; i,j x represents the distance between any two objects; bc The x-coordinate of the centroid of the ship's area positioning triangle; y bc This represents the centroid ordinate of the ship's regional positioning triangle.

[0069] Beneficial Effects: This invention provides a virtual training system for ship positioning based on a sextant simulator. By simulating the structure and operational logic of a real sextant, including functions such as line-of-sight adjustment, angle measurement, and error correction, trainees can master the use of a sextant in a virtual environment. By constructing mathematical models for astronomical and landmark positioning and optimizing the positioning results using the error triangle method, trainees can perform high-precision ship positioning training using a sextant. The sextant simulator allows trainees to operate a sextant for ship positioning training in a virtual environment, avoiding the complex scheduling and high costs of actual ship training. Through systematic training and assessment, trainees' operational skills with the sextant are evaluated in real time, effectively improving their ability to operate a sextant for astronomical and landmark positioning. Attached Figure Description

[0070] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0071] Figure 1 This is a schematic diagram of the sextant simulator virtual system of the present invention;

[0072] Figure 2 A diagram showing the two distances between the virtual observation vessel positions in this embodiment is provided.

[0073] Figure 3 A diagram showing the three-distance positioning of the virtual observation vessel in this embodiment is provided.

[0074] Figure 4 This is a schematic diagram of the Earth and celestial sphere structure in this embodiment;

[0075] Figure 5 This is a schematic diagram illustrating the modeling process and effects of the virtual training simulation scenario in this embodiment;

[0076] Figure 6 This is a schematic diagram of the 3D model of the sextant in this embodiment;

[0077] Figure 7 This is a 3D modeling effect diagram of the sextant in this embodiment;

[0078] Figure 8 This is a virtual simulation diagram of the sun in this embodiment;

[0079] Figure 9 This is a virtual simulation image of Sagittarius in this embodiment;

[0080] Figure 10 This is a virtual simulation image of the Ursa Major constellation in this embodiment;

[0081] Figure 11 This is the core block diagram of the sextant simulator virtual system in this embodiment. Detailed Implementation

[0082] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0083] This embodiment provides a virtual training system for ship positioning based on a sextant simulator, such as... Figure 1 As shown, it includes a 3D modeling and reproduction module for obtaining the structure of a sextant simulator; wherein, the 3D modeling and reproduction module is used to perform 3D modeling on an existing sextant simulator to obtain a virtually constructed sextant simulator, ensuring the consistency of the model with the appearance and layout of the real sextant, such as... Figures 6-7 As shown, the virtual sextant simulator is imported into Unity software for material assignment and lighting adjustment. The model's hierarchy and interactive areas are also set. Based on the virtual sextant simulator, a sextant measurement principle model is constructed. This model is based on the principle of plane mirror reflection, adjusting the mirror angle to align the target image with the horizontal line to measure the elevation angle. The angle reading consists of whole angles, fractional angles, and small vernier values, consistent with the actual equipment. Combining the elevation angle, azimuth angle, and observation position and time, the target's position in the horizon and equatorial coordinate systems is obtained through angular geometry. The method for virtualizing the sextant simulator is based on existing known technology and will not be elaborated further here.

[0084] Data setting module for setting virtual positioning practice data;

[0085] A simulation scenario construction module for setting up virtual training scenarios at sea based on virtual positioning practice data;

[0086] Specifically, such as Figure 5 As shown, the simulation scene construction module, based on pre-acquired radar data, electronic nautical chart data, and high-resolution image data of a specific location, uses 3DMax modeling and Unity3D engine rendering technology to construct a virtual training scene at sea. The method for constructing the virtual training scene at sea is a well-known existing technology and will not be elaborated upon here. It also includes precise mathematical modeling of the celestial bodies such as the Sun, Sagittarius, and Ursa Major based on astronomical principles. This precise mathematical model of celestial body orientation is implemented through a pre-set C# script. The simulation effect is as follows: Figures 8-10 As shown, high-precision terrain data is imported to obtain port and related building models to ensure the realism of the virtual environment;

[0087] A virtual interactive training module used to perform virtual training for astronomical positioning and virtual training for landmark positioning based on the sextant simulator structure obtained by the 3D modeling and reproduction module in the context of a virtual training scenario at sea.

[0088] A positioning model building module used to obtain astronomical positioning models and landmark positioning models;

[0089] The data setting module includes a positioning model construction module, a script editing and setting module for setting astronomical positioning training data and land landmark positioning training data, a stage operation scoring module, and a comprehensive evaluation storage module.

[0090] The script editing and setting module is used to set script data for virtual positioning exercises of navigation and positioning of marine vessels through a preset editing interface, and to set sub-script data for several operation training stages in the script data according to the training type of the virtual positioning exercise.

[0091] Furthermore, the sub-script data is used to characterize each operation training stage in the corresponding script data during virtual positioning practice;

[0092] The operation training phase includes at least the following phases: the image motion simulation training phase for the sextant moving mirror inspection and correction function, the image motion simulation training phase for the sextant fixed mirror inspection and correction function, the sextant index difference measurement simulation training phase, and the sextant celestial altitude measurement simulation training phase.

[0093] Specifically, the virtual interactive training module is used to set the virtual sextant interactive functions according to each operational training stage, which includes...

[0094] Virtual interactive operation during the image motion simulation training phase of sextant moving mirror inspection of correction function:

[0095] a. Place the sextant horizontally;

[0096] b. Pinch the clamp and rotate the indicator arm to between 30° and 40°;

[0097] c. Observe the sextant frame and the reflected angle of the sextant frame from the upper side of the sextant;

[0098] d. Adjust the calibration screws until the reflection angle frame and the direct viewing angle frame are on the same horizontal line, and check that the calibration is complete;

[0099] Virtual interactive operation during the image motion simulation training phase of sextant fixation function examination:

[0100] a. Place the sextant vertically;

[0101] b. Aim the viewpoint at the target object and observe for any errors.

[0102] c. Adjust the calibration screws until the objects on the telescope no longer overlap or separate, and the observed objects are fully displayed. The fixed lens check is complete.

[0103] Virtual interactive operation during the simulation training phase of sextant index difference measurement:

[0104] The instrument simulates the index difference caused by the offset of the sextant lens, generating a deviation effect consistent with actual observation. At the same time, it provides the water line, stars or the sun as reference targets. By adjusting the sextant calibration screw, the index difference is eliminated and the measurement accuracy is adjusted.

[0105] Virtual interactive operation during the training phase of sextant measurement of celestial altitude simulation:

[0106] Based on the principle of plane mirror reflection, the process of measuring the altitude angle of a celestial body is simulated by simulating that the angle of incidence of light is equal to the angle of reflection. The angle of the sextant is adjusted so that the line of sight of the target celestial body coincides with the horizontal plane, and the altitude angle of the celestial body is measured.

[0107] The stage operation scoring module is used to obtain the result data of the virtual interactive training and, based on the preset operation standard threshold, to score the operation level of the result data of the training operation in each operation training stage.

[0108] The operation level is a score threshold obtained by manually dividing the operation standard threshold.

[0109] The comprehensive evaluation and storage module is used to acquire the result data and operation level scores of each operation training stage, and based on the result data of each operation training stage, obtain the virtual training results of ship navigation and positioning according to the constructed astronomical positioning model or land landmark positioning model.

[0110] In a specific embodiment, the method by which the positioning model construction module obtains the astronomical positioning model is as follows: Figures 2-4 Specifically, it includes the following steps:

[0111] S01: Construct a celestial orientation mathematical model to obtain celestial data in real time through the celestial orientation mathematical model; and the celestial data includes celestial altitude and celestial orientation;

[0112] To dynamically simulate and obtain the dynamic orientation of celestial bodies through celestial models;

[0113] Specifically, the method for constructing the mathematical model of celestial orientation in S01 is as follows:

[0114] S011: Construct a mathematical model for the Julian Day, and calculate and obtain the Julian Day parameter J based on the input year / month / day and UTC. Its expression is:

[0115]

[0116] In the formula: year represents the input year of the Julian Day mathematical model; month represents the input month of the Julian Day mathematical model; date represents the input day of the Julian Day mathematical model; GMT represents the input world time of the Julian Day mathematical model;

[0117] S012: Based on the Julian sun parameter J and the simulation time of the virtual sextant simulator, obtain the declination Dec and local time angle LHA of the celestial body. Their expressions are as follows:

[0118]

[0119] In the formula: M represents the standard meridian of the simulated time zone; t s Indicates the simulation time of the simulation scenario;

[0120] S013: Based on the declination Dec and local time angle LHA of a celestial body, construct a method for calculating the altitude h of the celestial body. c With celestial position A c The mathematical model of celestial orientation is expressed as follows:

[0121]

[0122] S02: Based on the sextant measurement method, measurement data is obtained according to the dynamic orientation of celestial bodies;

[0123] The measurement data includes at least the measurement data of celestial altitude and index difference;

[0124] Furthermore, the measured data of the index difference is the celestial body time angle deviation;

[0125] Based on celestial altitude data and index difference measurement data, virtual ship position lines are drawn and obtained in conjunction with ship navigation scenarios to determine the ship position of the preset virtual ship, and the error triangle method is used to optimize the virtual ship position to obtain an astronomical positioning model.

[0126] Specifically, S02 includes the following steps:

[0127] S021: Based on the sextant measurement method, measurement data is obtained according to the dynamic orientation of celestial bodies;

[0128] Based on the celestial altitude data and the index difference measurement data, the true altitude h of the celestial body is obtained. t And the corresponding celestial local time angle LHA1; its expression is:

[0129] h t =h0+d+p1+p2

[0130]

[0131] In the formula: GHA represents the Green's time angle of the observed celestial body; ms represents the basic variable of the Green's time angle; v represents the time angle deviation; p1 represents the longitude of the virtual ship's environment; p2 represents the celestial body altitude correction; p0 represents the solar additional correction parameter; h0 represents the celestial body altitude measured by manipulating the sextant; d represents the eye height difference.

[0132] S022: Based on the local time angle LHA1 of the celestial body, obtain the declination Dec of the geographical location point b corresponding to the observed celestial body position B according to step S13;

[0133] S023: Based on the zenith position of the virtual ship (Z) cThe celestial position B and the Earth's pole P N Draw an astronomical triangle for the vertices and project it onto the Earth's surface to obtain the projected triangle cbp. n ;

[0134] With geographical point b as the center and the true altitude h of the celestial body t Draw the ship position curve II with radius , and intersect the ship position curve II with the projected triangle cbp. n The intersection point k is the tangent point Ⅱ-Ⅱ of the ship position curve II, i.e., the ship position line; the method or means of drawing the ship position curve is the existing known technology and is not the inventive point of this application, so the drawing process will not be described in detail here.

[0135] S024: Confirm the number of celestial bodies involved in the ship's navigation and positioning, and the number of celestial bodies includes at least two or three;

[0136] If it is confirmed that there are two celestial bodies, then two ship position lines are obtained based on step S023, and the intersection of the two ship position lines is taken as the ship position of the preset virtual ship. Its expression is

[0137]

[0138] Z 1,2 =90°-h t1,2

[0139] In the formula: Z 1,2 Indicates intermediate parameter variables; h t1,2 Indicates the true altitude of the corresponding two celestial bodies;

[0140] If the number of celestial bodies is confirmed to be three, then three ship position lines are obtained based on step S023, and the intersection of the three ship position lines is used as the vertex to obtain the ship area positioning triangle.

[0141] The error triangle method is used to optimize the ship's regional positioning triangle. This involves obtaining the angle bisectors of the three angles of the ship's regional positioning triangle and using the intersection of the angle bisectors as the ship's position for the preset virtual ship. Its expression is

[0142]

[0143] In the formula: R represents the Earth's radius; d i,j Let i,j = 1,2,3;

[0144] This embodiment also includes a method for optimizing the position of a preset virtual ship using the error radius. Specifically, the optimal position of the ship is obtained through a weighted average method, the expression of which is:

[0145]

[0146] In the formula: p i Indicates the position of the preset virtual ship; E σi This represents the random error of the i-th ship's position line;

[0147] The error radius r is used to further correct the ship's position to reduce the error in the ship's optimal position. Its expression is:

[0148]

[0149] In the formula: θ represents the angle between the position lines of two adjacent points; E σ This indicates random error in the ship's position line;

[0150] Specifically, the method for the positioning model construction module to obtain the landmark positioning model includes the following steps:

[0151] S001: Determine the number and height of the targets used for ship positioning;

[0152] The number of objects includes at least two or three;

[0153] S002: If the number of targets is confirmed to be two, obtain the known target height H using the sextant simulator obtained from the 3D modeling and reproduction module. i object M i vertical angle α i And according to the vertical angle α i With the height H of the object i Obtain the virtual ship landmark measurement distance D i , i = 1, 2;

[0154] The virtual ship landmark measurement distance D i The expression is

[0155]

[0156] S003: The virtual azimuth angle of the target is obtained by measuring the virtual azimuth angle of the target with the measurement error ΔC set according to the empirical value, and the true azimuth angle TB of the target is obtained by summing the virtual azimuth angle of the target with the measurement error ΔC set according to the empirical value.

[0157] Two bearing lines are drawn along the TB±180° direction, and the intersection of the two bearing lines is taken as the pre-defined virtual ship's position, expressed as follows:

[0158]

[0159] In the formula: M1(x1,y1) and M2(x2,y2) represent the position coordinates of the two objects respectively; e represents the eccentricity of the elliptical meridian; D1 and D2 represent the measured distances from the virtual ship to the two objects respectively; A, B, and C represent intermediate parameters.

[0160] This embodiment also includes obtaining the ship position of the preset virtual ship according to S003, and using the distance position The optimal ship position is obtained by optimizing it with the radius r of the error circle, and its expression is:

[0161]

[0162] Where: ε B Indicates systematic error; E represents the distance from the ship to the target as measured by a sextant. σ θ represents the random error of the ship's position line; θ represents the azimuth angle between the two azimuth lines.

[0163] S004: If the number of targets is confirmed to be three, obtain the known target height H using the sextant simulator obtained from the 3D modeling and reproduction module. i object M i vertical angle α i And according to the vertical angle α i With the height H of the object i Obtain the virtual ship landmark measurement distance D i i = 1, 2, 3;

[0164] S005: The virtual azimuth angle of the object is obtained by measuring the virtual azimuth angle of the object using a sextant simulator, and the true azimuth angle TB of the object is obtained by summing the virtual azimuth angle of the object with the measurement error ΔC.

[0165] Three azimuth lines are drawn along the TB±180° direction, and the intersection of the three azimuth lines is used as the vertex to obtain the ship's regional positioning triangle;

[0166] S006: The position of the preset virtual ship is determined using the center-of-gravity method based on the ship's regional positioning triangle. The expression is as follows:

[0167]

[0168] In the formula: x 12 y 12 x 13 y 13 x 23 y 23 The coordinates of the vertices of the ship's area positioning triangle are represented; M1(x1,y1), M2(x2,y2), and M3(x3,y3) represent the position coordinates of the three landmarks, respectively; θ miM represents the observation angle between the sextant simulator and each object, where i = 1, 2, 3; i,j x represents the distance between any two objects; bc The x-coordinate of the centroid of the ship's area positioning triangle; y bc This represents the centroid ordinate of the ship's regional positioning triangle.

[0169] This embodiment also includes the final ship position p. 最优 And it is optimized using the radius r of the error circle:

[0170]

[0171] In the formula: E σi θ represents the random error of the i-th azimuth line; i D represents the angle between the azimuth lines of two adjacent targets. i Let i be the distance from the ship to the target measured by a sextant, i = 1, 2, 3;

[0172] Based on the error tolerance difference between the virtual training results and the actual ship navigation and positioning results, it is determined whether the virtual training of the trainees has met the standards. Based on the operation level score, the operation training stage that does not meet the virtual training requirements is identified, so as to carry out targeted simulation training.

[0173] This embodiment demonstrates an implementation case of the training and assessment module for landmark distance positioning, as follows:

[0174] S100: Enter the pre-set student ID to log in to the system. After logging in, select the landmark distance positioning training. Set the scenario to the waters of the Zhongshan Islands in China. The ship speed is 8 knots and the heading is 92.8°. The landmark parameters are shown in Table 1.

[0175] Table 1. Landmark Parameters in Virtual Training Scenarios

[0176]

[0177] S200: Through the virtual interactive training module, trainees use a pre-defined script to perform adjustments on the moving and fixed mirrors of the sextant simulator, which is virtually constructed by the 3D modeling and reproduction module, in order to align the top of the target landmass with the horizontal line and read the sextant data.

[0178] S300: Input the vertical angle and height data of Xiaoban Island, Huangxing Island and Dongfushan measured by the sextant into the landmark positioning model, and obtain the distance between the ship and the target as shown in Table 2 based on the landmark positioning model;

[0179] Table 2. Landmark Parameters in Virtual Training Scenarios

[0180]

[0181] S400: Based on the data in Table 2, the coordinates of the vertex of the error triangle are obtained, and the calculated coordinates of the vertex of the error triangle are compared with the coordinates of the electronic chart in the training system in Table 3.

[0182] Table 3. Comparison of the estimated error triangle and the actual error triangle

[0183]

[0184] S500: Set the standard deviation of random error σ B =1.5°. Based on the distance calculation results of the landmarks in Table 2 and the formula for the three-distance ship position error radius, the three-distance positioning error radius is obtained as 0.0041 nautical miles. The calculated virtual ship position is (122.5569, 30.1659), and the virtual ship position in the scenario is (122.5580, 30.1657). The actual error of the land-based ship positioning based on the three-mark distance is 0.00118 nautical miles. The positioning training and assessment show that it has passed.

[0185] In this embodiment, the sextant simulator virtual system, such as Figure 11 As shown, it also includes a sextant virtual operation teaching, training and assessment module: used to guide students to master the inspection and correction operation of the sextant moving mirror and fixed mirror through pictures, texts and videos; and simulate actual operation to help students master the correction method, and display readings and adjustment functions simultaneously; at the same time, it sets error thresholds, evaluates students' operation performance and generates score records to ensure that students are proficient in sextant operation;

[0186] Sextant index difference measurement teaching, training and assessment module: Through virtual operation, students are guided to master the index difference measurement method. In the training stage, students simulate operation and learn to measure the apparent radius of the sun with a sextant. In the assessment stage, the error range is set, the students' operating accuracy is evaluated and the scores are recorded.

[0187] Sextant for measuring celestial altitude: This module guides students through text, images, and videos to master the skill of measuring celestial altitude angles. During the training phase, students simulate altitude measurement by aligning the sextant with the celestial body. Based on the training mode, observation time weighting and accuracy thresholds are added for assessment.

[0188] The basic principles of astronomical and landmark positioning are demonstrated and interacted with in a virtual environment. The working principle of the astronomical and landmark positioning model is dynamically displayed, and interactive functions are added to allow students to understand the principles of astronomical and landmark positioning through operation.

[0189] The marine sun alignment positioning teaching, training and assessment module: trains trainees to use a sextant to measure the altitude angle and azimuth angle and to perform sun alignment positioning methods. It is equipped with random question generation and assessment functions to improve practical operation skills.

[0190] Distance positioning teaching, training and assessment module: Based on the landmark positioning model, the landmark positioning process is simulated to train trainees to use a sextant to perform accurate distance measurement and positioning. The system demonstrates the basic principles and steps, and scores the trainees based on parameters such as positioning accuracy and operation time after training, providing corresponding assessment results to improve trainees' operational skills.

[0191] Samsung Positioning Teaching, Training and Assessment Module: Based on the astronomical positioning model, this module simulates the astronomical positioning process and demonstrates the principles and steps of Samsung positioning in detail. It aims to train students to use a sextant for accurate astronomical positioning. After students complete the operation training in the virtual environment, the system scores them based on indicators such as operational efficiency and provides the assessment results.

[0192] The comprehensive assessment system module allows for setting exam content in the backend, generating random questions, customizing tasks, and conducting assessments. It records the operational results and steps of each assessment point in the student's single or comprehensive practical simulation, and automatically provides scores based on the recorded results and an assessment mathematical model, enabling students to conduct targeted training based on the scores.

[0193] This embodiment simulates the structure and operational logic of a real sextant, including functions such as line-of-sight adjustment, angle measurement, and error correction. This allows trainees to master the use of a sextant in a virtual environment. By constructing mathematical models for astronomical and landmark positioning and optimizing the positioning results using methods such as error triangles and error radii, trainees can perform high-precision ship positioning training using a sextant. The sextant simulator allows trainees to operate a sextant for ship positioning training in a virtual environment, avoiding the complex scheduling and high costs of actual ship training. Through systematic training and assessment, trainees' operational skills with the sextant are evaluated in real time, effectively improving their ability to operate a sextant for astronomical and landmark positioning.

[0194] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sextant simulator based virtual training system for ship positioning, characterized in that, The application relates to a virtual training system for celestial navigation and landmark positioning, which comprises a 3D modeling reproduction module for acquiring sextant simulator structure, a data setting module for setting virtual positioning practice data, a simulation scene construction module for setting a marine virtual training scene according to the virtual positioning practice data, a virtual interactive training module for carrying out celestial positioning virtual training and landmark positioning virtual training according to the marine virtual training scene and based on the sextant simulator structure acquired by the 3D modeling reproduction module, a positioning model construction module for acquiring celestial positioning models and landmark positioning models, the method for acquiring the celestial positioning model by the positioning model construction module specifically comprises the following steps: S01: constructing a celestial body azimuth mathematical model to acquire celestial body data in real time through the celestial body azimuth mathematical model; the celestial body data comprises celestial body altitude and celestial body azimuth; acquiring the dynamic azimuth of the celestial body by dynamically simulating the celestial body through the celestial body model; S02: acquiring measurement data according to the dynamic azimuth of the celestial body based on a sextant measurement method; the measurement data at least comprises celestial body altitude and index difference measurement data; the index difference measurement data is the celestial body hour angle excess error; acquiring a virtual ship position line by combining the celestial body altitude data and the index difference measurement data, drawing and acquiring the virtual ship position line in a marine navigation scene to determine the position of a preset virtual ship, and optimizing the virtual ship position by an error triangle method to acquire the celestial positioning model; the data setting module comprises a script editing setting module for setting celestial positioning training data and landmark positioning training data based on the positioning model construction module, a stage operation scoring module and a comprehensive evaluation storage module; the script editing setting module is used for setting script data of virtual positioning practice about marine ship navigation positioning through a preset editing interface, and setting sub-script data of a plurality of operation training stages in the script data according to the training type of the virtual positioning practice; the sub-script data is used for representing each operation training stage in the script data during the virtual positioning practice; the operation training stage at least comprises an image motion simulation training stage of sextant mirror movement checking and homing, an image motion simulation training stage of sextant mirror fixing checking and homing, a sextant index difference measurement simulation training stage and a sextant measurement celestial body altitude simulation training stage; the stage operation scoring module is used for acquiring result data of the virtual interactive training, and scoring the result data of the training operation in each operation training stage based on a preset operation standard threshold value; the operation level is a score threshold value obtained by artificially dividing according to the operation standard threshold value; the comprehensive evaluation storage module is used for acquiring the result data and the operation level score of each operation training stage, obtaining a virtual training result of ship navigation positioning based on the result data of each operation training stage according to the constructed celestial positioning model or landmark positioning model, 2. A sextant simulator based virtual training system for ship positioning as claimed in claim 1, wherein, judging whether the virtual training of the operation trainee meets the requirements according to the error tolerance difference between the virtual training result and the actual ship navigation positioning result, and confirming the operation training stage which does not meet the virtual training requirements based on the operation level score to carry out targeted simulation training. S011: Construct a Julian day mathematical model, and calculate and obtain a Julian day parameter according to an input year / month / day and a universal time J The expression is In the formulae: represents the input year of the Julian day mathematical model; represents the input month of the Julian day mathematical model; represents the input day of the Julian day mathematical model; represents the input universal time of the Julian day mathematical model; S012: obtaining the julian day parameter J and the simulation time of the simulation scene of the virtual sextant simulator, obtaining the declination of the celestial body the method for constructing the celestial body azimuth mathematical model in S01 is and the local hour angle of the celestial body Dec whose expression is In the formulae: represents a simulation time zone standard meridian; represents a simulation time of the simulation scene; S013: according to the declination of the celestial body LHA with the local hour angle of the celestial body Dec LHA , a mathematical model for calculating the altitude of the celestial body with the azimuth of the celestial body A c whose expression is 。 3. A sextant simulator based virtual training system for ship positioning as claimed in claim 2, wherein, The S02 specifically comprises the following steps: S021: obtaining measurement data according to the dynamic azimuth of the celestial body based on the sextant measurement method; According to the celestial body height data and the index difference measurement data, the true height of the celestial body is obtained h t and the corresponding celestial body local hour angle LHA1 ; The expression is wherein: GHA represents the Greenwich hour angle of the observed celestial body; m.s represents the Greenwich hour angle base variable; v represents the hour angle excess; represents the environment longitude where the virtual ship is located; represents the celestial body altitude correction; represents the sun additional correction parameter; represents the manipulated sextant measured celestial body altitude; d represents the eye height difference; S022: based on the local hour angle of the celestial body LHA1 , the observed celestial body position is acquired according to step S13 B the corresponding geographical position point b the declination Dec. S023: drawing an astronomical triangle with the position of the virtual ship as a vertex Z c the position of the celestial body B and the Earth's poles P N draw an astronomical triangle with the position of the virtual ship as a vertex and project it onto the Earth's surface to obtain a projected triangle; with the geographical position point b as the center and the true altitude of the celestial body as the radius, draw a position curve I-I, and pass through the intersection point of the position curve I-I and the projection triangle h t as the center and the true altitude of the celestial body as the radius, draw a position curve I-I, and pass through the intersection point of the position curve I-I and the projection triangle k get the position curve tangent point II-II of the position curve I-I, i.e. the position line S024: confirming the number of celestial bodies participating in the navigation and positioning of the ship, and the number of celestial bodies is at least two or three; If the number of celestial bodies is confirmed to be two, two lines of position are obtained based on step S023, and the intersection of the two lines of position is taken as the ship position of the preset virtual ship The expression is wherein: denotes an intermediate parameter variable; denotes the true altitude of a celestial body corresponding to two celestial bodies; If it is confirmed that the number of celestial bodies is three, three ship position lines are obtained based on step S023, and a ship area positioning triangle is obtained with the intersection of the three ship position lines as the vertex; The error triangle method is used to optimize the ship area positioning triangle, that is, the angle bisectors of the three angles of the ship area positioning triangle are obtained, and the intersection point of the angle bisectors is taken as the ship position of the preset virtual ship The expression is wherein: R represents the earth radius; represents the spherical distance between any two vertices and .

4. A sextant simulator based virtual training system for ship positioning as claimed in claim 1 wherein, The method for obtaining the landmark positioning model by the positioning model construction module specifically comprises the following steps: S001: constructing the number of landmarks and the height of the landmarks for ship positioning; The number of landmarks is at least two or three; S002: If the number of targets is two, obtain the height of the known target through the sextant simulator obtained based on the 3D modeling reproduction module of the target of the vertical angle , and obtain the virtual ship target measurement distance according to the vertical angle and the target height , ; The virtual ship target measures distance The expression is S003: Measure the target virtual azimuth angle respectively through the sextant simulator, and compare the target virtual azimuth angle with the measurement error set according to the experience value Sum up the target true azimuth angle TB ; and along directions, the intersection of the two azimuth lines as the ship position of the preset virtual ship, which is expressed as C= wherein: M 1( ) M 2( ) represent the position coordinates of two targets, respectively; e represents the eccentricity of the elliptic meridian; D 1and D 2represent the measured distances from the virtual ship to the two targets, respectively; , C represents an intermediate parameter quantity; S004: If the number of targets is three, obtain the height of the known target through the sextant simulator obtained based on the 3D modeling reproduction module of the target of the vertical angle , and obtain the virtual ship target measurement distance according to the vertical angle and the target height , ; S005: Measure the target virtual azimuth angle respectively through the sextant simulator, and obtain the target virtual azimuth angle and the measurement error Sum the target true azimuth angle TB ; and along direction to draw three azimuth lines, and the intersection of the three azimuth lines is taken as a vertex to obtain a ship area positioning triangle. S006: determining the ship position of the preset virtual ship according to the ship area positioning triangle by using the barycentric method, and the expression is wherein: , , , , , represents the coordinate position of the vertex of the ship area positioning triangle; M 1 ) ,M 2 , M 3 respectively represent the coordinate position of the three objects; represents the observation angle between the sextant simulator and each object and ; represents the distance between any two objects; represents the horizontal coordinate of the center of gravity of the ship area positioning triangle; represents the vertical coordinate of the center of gravity of the ship area positioning triangle.

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