A method for real-time calculation and two-dimensional display of shielding margin of shipborne TT&C equipment

Abstract

The present application relates to a kind of shipborne measurement and control equipment sheltering margin real-time calculation and two-dimensional display method, including overall view and sub-equipment view;Wherein overall view can be observed the linkage change of heading and each device azimuth angle, pitch angle and sheltering margin in real time, accordingly can directly obtain the conclusion whether ship steering is reasonable;Sub-equipment view is used to monitor whether the device falls in and avoids shadow area in measurement and control arc segment, accordingly can directly judge whether sub-equipment enters sheltering area;The present application uses the method of data and display separation, designs general database table, realizes the configurability of antenna sheltering data, the selectivity of antenna equipment data display and the selectivity of ship posture ship position data source, applicable to each ship different equipment.This method can calculate and display the sheltering margin of antenna equipment in real time, and is displayed in real time through two-dimensional graphics, provides decision information for judging whether shipborne antenna is tracked and is sheltered.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of space measurement working condition design, and relates to a shipborne antenna device shielding margin real-time calculation and two-dimensional display method. The method acquires the azimuth, elevation and other information of the shipborne antenna device in real time, combines with the heading information, and calculates and displays the shielding margin of the antenna device in real time, so as to provide decision information for judging whether each antenna is shielded during tracking. BACKGROUND

[0002] The sea activity measurement and control platform is the organic combination of the ship and the special system including the measurement and control and communication equipment. Various large test equipment is densely arranged along the bow and stern line of the platform, and the electromagnetic signals are easily shielded and reflected by the antenna covers and the ship body buildings such as the chimney, the mast and the bridge, thereby affecting the signal strength, generating interference and further affecting the measurement accuracy. In order to ensure the equipment performance, the space measurement and control task is reasonably planned in the design according to the target theoretical flight trajectory, the ship position and the antenna pointing are reasonably planned, and the shielding area is avoided. If the task sea area is limited, or the target elevation is too low, or the target maneuvering range is too large, the shielding problem is inevitable, and a shielding prediction model needs to be researched. In the task implementation process, the shielding margin is calculated and monitored in real time, and the heading is changed to take corresponding measures, so that the target is kept in the whole process of unobstructed view and smooth communication, thereby ensuring the smooth completion of the arc segment task.

[0003] The meaning of the shielding margin: the shielding area is related to the position, height and width of the shielding object and the geometric relationship between them, and can be expressed as a shielding function. Assuming that the shielding object is in a static state, the shielding shadow will appear only when the azimuth angle and the elevation angle of the shielded device satisfy a certain relationship from the perspective of the shielded device. Therefore, the shielding relationship can be regarded as a function of the azimuth angle x and the elevation angle y. The meaning of the shielding margin is: the distance (unit: °) between the current azimuth pointing and the nearest shadow edge at the current elevation angle. When the shielding margin is negative, it means that it falls into the shadow area; when the shielding margin takes the maximum value 360°, it means that there is no shielding in the 360° direction.

[0004] Figure 1 A typical antenna shielding azimuth diagram is shown, and the shielding area in the diagram is described as follows:

[0005] (1) When the azimuth angle is in the range of (20°-160°, -20°-160°) and the elevation angle is greater than -5°, there is no shielding.

[0006] (2) When the azimuth angle is in the range of 0-±20° and the elevation angle is greater than 33°, there is no shielding.

[0007] (3) When the azimuth angle is in the range of (160°-200°) and the elevation angle is greater than 24°, there is no shielding.

[0008] In order to avoid the shielding, the shielding margin should be kept or increased as much as possible. There are two strategies to increase the shielding margin: one is to increase the elevation angle, and the other is to change the azimuth direction. For the first strategy, the elevation angle can be increased by tilting the ship body in theory while keeping the target tracking, but this method is not easy to operate and it is difficult to maintain the tilting action in the sea wave environment. For the second strategy, the translation of the antenna azimuth angle can be realized by using the ship body turning, which is easy to operate and the angular velocity and the range of the heading change are relatively controllable. Therefore, for the task with the risk of shielding, the strategy of changing the heading measurement is generally adopted to deal with it.

[0009] The elements of the changing heading measurement include the starting time, the turning direction, the turning angular velocity and the turning range. These four elements are closely related to the shielding margin. In order to accurately control these four elements and realize the shielding avoidance, the shielding margin needs to be calculated, monitored and predicted in real time. SUMMARY

[0010] The technical problem to be solved by the present application is to provide a shipborne antenna device shielding margin real-time calculation and two-dimensional display method, which can be used for real-time calculation and display of the shielding margin of multiple shipborne antenna devices. The present application adopts a time-driven method to calculate the device shielding margin in real time, and the calculation frequency is 1Hz.

[0011] The technical scheme adopted by the present application to solve the above problems is a shipborne antenna device shielding margin real-time calculation and two-dimensional display method, which comprises the following steps:

[0012] Step A, database design: including the interrelated "antenna shielding area description table", "antenna device identification table" and "ship attitude and position data table"; reading the database tables in a certain order and rules, and checking the legality of the data in the database tables;

[0013] Step B, display picture design: including the overall view and the device view, which are complementary to each other. The overall view is used for real-time observation of the linkage change of the heading and the azimuth angle, the elevation angle and the shielding margin of each device, and the conclusion whether the ship turning is reasonable can be directly obtained. The device view is used for monitoring whether the device falls into or avoids the shadow area in the whole measurement control arc segment.

[0014] Step C, shielding margin calculation: (1) using the top view projection coordinate system, the shielding area of a single device and the projection curve of the device pointing axis are drawn; (2) using a 360° dial to draw the azimuth angle of the device, the azimuth indicating line drawn from the center of the dial indicates the actual azimuth angle of the device, and the radial length of the indicating line indicates the actual elevation angle of the device; (3) the radial direction of the dial represents the elevation angle, which gradually increases from the center of the dial to the outside, and the 0° elevation angle is at 1 / 2 of the radial length.

[0015] Step D, data two-dimensional display: the received data is time-stamped and aligned, the shielding allowance of each device is calculated at the whole second point and displayed in real time on the overall view and the sub-view; if the shielding allowance is too small or has a negative trend, an alarm will be prompted on the interface and a steering suggestion will be given.

[0016] Preferably, the "antenna shielding area description table" includes 7 fields, the field "area identification number" is the primary key, each shielding area is configured with an identification number, and the same antenna can have multiple "area identification numbers", and these areas together form the shielding area of the antenna; each shielding area is composed of the fields "front left azimuth angle", "front right azimuth angle", "rear right azimuth angle", "rear left azimuth angle", and "elevation angle", and the field "antenna identification number" is the foreign key, used to point to the "antenna device identification table";

[0017] The "antenna device identification table" stores the basic information of the antenna device of the measurement platform, including the antenna identification number, the antenna name, the antenna data identification code, whether to calculate, and the ship attitude and position identification number, wherein the field "antenna data identification code" is used to identify the azimuth and elevation data of the antenna from network data; and the field "ship attitude and position identification number" is the foreign key, pointing to the "ship attitude and position data table", used to specify the ship attitude and position device matched with the antenna;

[0018] The "ship attitude and position data table" stores the basic information of the ship attitude and position device, and when there are multiple sets of ship attitude and position measurement devices, the data of one set of measurement devices is selected for actual calculation, including the "ship attitude and position identification number" as the primary key, the "ship attitude and position device name", and the "ship attitude and position device identification code".

[0019] Preferably, step A specifically includes 1) reading the "antenna shielding area description table" according to the "antenna identification number", and reading while sorting according to the elevation angle from small to large, generating the shielding area array of each antenna, forming data in the following form: {antenna identification number, [front left azimuth angle, front right azimuth angle, rear right azimuth angle, rear left azimuth angle, elevation angle]}, wherein the "+" sign indicates that there are multiple groups of data; +

[0020] 2) reading the "antenna device identification table" according to the "antenna identification number" from small to large, converting the "antenna data identification code" therein from hexadecimal to decimal; according to the "ship attitude and position identification number" therein, reading the corresponding record from the "ship attitude and position data table", and associating the "ship attitude and position device identification code" with the "antenna identification number";

[0021] Preferably, the size relationship of the azimuth angle is:

[0022] Front left azimuth angle ≤ front right azimuth angle ≤ rear right azimuth angle ≤ rear left azimuth angle. ​

[0023] Preferably, the overall view in step B includes counting the number of records in the "antenna device identification table" field "whether to calculate" as TRUE, in the order of "antenna identification number" from small to large, the left part of the view is drawn in turn the shielding margin diagram of each device; the right part of the view displays the heading information of the measurement platform, the azimuth data, the elevation data and the shielding margin data of each device.

[0024] Preferably, the number of sub-equipment views in step B is consistent with the number of shielding margin diagrams in the overall view, each sub-equipment view is only different in device data and shielding data, and the display mode is completely consistent, according to the data of the device in the "antenna shielding area description table", the shielding area of a single device and the projection curve of the device pointing axis are drawn in the top view coordinate system; a 360° dial is drawn to express the azimuth angle of the device, the azimuth indicating line from the center of the dial indicates the actual azimuth angle of the device, and the radial length of the indicating line indicates the actual elevation angle of the device, which is initialized to 0°; the radial scale of the dial is drawn to express the elevation angle of the device, and a 0° elevation angle reference circle is drawn at 1 / 2 of the radial length.

[0025] Preferably, on the ship measurement and control data service network, two types of data are collected according to the communication protocol: ①the original measurement data of the measurement and control device, from which the azimuth angle and the elevation angle of the device under the deck system are extracted; ②the ship attitude and position data of the inertial navigation device, from which the current position, heading and speed information are obtained.

[0026] Compared with the prior art, the advantages of the present application are that:

[0027] 1、The ship-borne measurement and control device shielding margin real-time display view designed in the present application can observe the linkage changes of the heading and the azimuth angle, the elevation angle and the shielding margin of each device in real time, and thus the conclusion of whether the ship turning is reasonable can be intuitively obtained; the sub-equipment view is used to monitor whether the device falls into and avoids the shadow area in the measurement and control arc segment, and thus whether the sub-equipment enters the shielding area can be intuitively judged.

[0028] 2、The "antenna shielding area description table", the "antenna device identification table" and the "ship attitude and position data table" designed in the present application realize the configurability of the antenna shielding data, the selectivity of the antenna device data display and the selectivity of the ship attitude and position data source, and are suitable for different devices of each ship, and have strong applicability. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1is the blocking relationship schematic diagram involved in the present application. The horizontal coordinate x is the azimuth angle, and the vertical coordinate y is the elevation angle, both of which adopt the deck coordinate system, wherein the azimuth angle x is [0°, 360°], and the elevation angle y is [0°, 90°]. The diagram shows that there is blocking when the azimuth angle is in [0°, 20°] and the elevation angle is <= 33°; there is blocking when the azimuth angle is in [160°, 200°] and the elevation angle is <= 24°; there is blocking when the azimuth angle is in [340°, 360°] and the elevation angle is <= 33°; and there is no blocking in the remaining area. For the equipment on the measuring platform, the blocking shadow generally appears on the bow and stern line of the ship, i.e. is distributed on both sides of x = 0 and x = 180.

[0030] Figure 2 is the overall view of the satellite blocking angle real-time display designed in the present application. A 360° dial is used to draw the ship heading, and the heading indication line at the center of the dial indicates the actual heading of the ship; the blocking margin diagrams of each equipment are sequentially drawn on the heading indication line, and the blocking situation and the azimuth direction of the equipment are drawn on each diagram, so that the overall situation of the blocking of each equipment can be easily known, i.e. when the azimuth direction on the diagram enters the shadow part, the equipment is blocked; the right part of the view sequentially displays the heading information of the measuring platform, the azimuth data, the elevation data and the blocking margin data of each equipment, wherein the blocking margin data is displayed in red color when the equipment is blocked.

[0031] Figure 3 is the partial view of the satellite blocking angle real-time display designed in the present application. A top view projection coordinate system is used to draw the blocking area of a single equipment and the projection curve of the equipment pointing axis; a 360° dial is used to draw the azimuth angle of the equipment, and the azimuth indication line drawn from the center of the dial indicates the actual azimuth angle of the equipment, and the radial length of the indication line indicates the actual elevation angle of the equipment; the radial direction of the dial represents the elevation angle, and the elevation angle gradually increases from the center of the dial to the outside. DETAILED DESCRIPTION

[0032] The present application is further described in detail below with reference to the embodiments of the drawings.

[0033] A shipborne antenna equipment blocking margin real-time calculation and two-dimensional display method. The method comprises the following steps:

[0034] Step A, database design. The present application designs three database tables: an antenna blocking area description table, an antenna equipment identification table and a ship attitude and position data table.

[0035] Step A.1, design the antenna blocking area description table to store the azimuth and elevation information of the antenna blocking area. The field "antenna identification number" is a foreign key, pointing to the antenna equipment identification table; the azimuth angle is the angle between the deck system and the north direction, clockwise positive and counterclockwise negative.

[0036] Table 1 Antenna Shading Area Description Table

[0037]

[0038] Step A.2, design the "Antenna Equipment Identification Table" to store the basic information of the measuring platform antenna equipment, including antenna identification number, antenna name, antenna data identification code, etc. The field "antenna data identification code" is used to identify the azimuth and elevation data of the antenna from the network data; the field "ship attitude and position identification number" is a foreign key pointing to the "ship attitude and position data table" to specify the ship attitude and position equipment matched with the antenna.

[0039] Table 2 Antenna Equipment Identification Table

[0040]

[0041]

[0042] Step A.3, design the "ship attitude and position data table" to store the basic information of the ship attitude and position equipment. When there are multiple sets of ship attitude and position measuring equipment, the data of one set of measuring equipment should be selected for actual calculation.

[0043] Table 3 Ship Attitude and Position Data Table

[0044] Field Type Meaning Ship position identification number Integer Primary key, numbered from 1 Ship position device name String Chinese name of the antenna Ship position device identification code Hexadecimal integer Hexadecimal integer starting with 0x, used to identify ship position data from the network

[0045] Step B, display screen design. The display screen is designed in the whole view + device view way, and the number of devices in the whole view and the number of sub-views are closely related to the "antenna equipment identification table" configured by the user, and the value is consistent with the number of "whether to calculate" field value in the table. "Yes".

[0046] Step B.1, whole view design. The whole view draws the ship heading and each device on a dial, and the user can observe the real-time changes of the heading and the device azimuth, elevation and shading margin, and can intuitively draw the ship turning conclusion, as shown in Figure 2

[0047] Step B.2, sub-device view design. The sub-device view uses the top-down projection coordinate system to draw the shading area of a single device and the projection curve of the device pointing axis, and the user can monitor whether the device falls into and avoids the shadow area during the task period, Figure 3 which shows the shading area of the lightning detection equipment and the process of a lateral measurement.

[0048] ​Step C, Design of the Obstruction Margin Calculation Algorithm. This algorithm is based on the obstruction data in the "Antenna Obstruction Area Description Table". Assume that the obstruction array of a certain antenna is [front left azimuth, front right azimuth, rear right azimuth, rear left azimuth, elevation angle], and has been sorted in descending order of elevation angle, where the i-th element is denoted as sheltArray[i]. Assume the azimuth angle of the current device is azimAngle and the elevation angle is eleAngle. Then, the obstruction margin calculation algorithm is as follows:

[0049] Step C.1: If eleAngle is greater than the pitch angle in sheltArray[0], then the device is unobstructed, i.e. the obstruction margin is 360°, and the obstruction margin calculation ends; otherwise, proceed to step C.2.

[0050] Step C.2: Find the position of eleAngle in the occlusion array, i.e., find the position that satisfies...

[0051] “sheltArray[i].pitch angle >= eleAngle > sheltArray[i+1].pitch angle”

[0052] The data element. If the search is successful, then record the occlusion angle data in sheltArray[i] and execute step C.3; if the search fails, then use the occlusion angle data of the last data element in the sheltArray[] array.

[0053] Step C.3: Based on the occlusion azimuth data in sheltArray[i], calculate the occlusion margin by category. First, the value of "front left azimuth" needs to be converted to between 0 and 360°, that is, if "front left azimuth < 0", then "front left azimuth += 360". Then perform the following operations:

[0054] (1) If the occlusion angle data shows "Front left azimuth angle == front right azimuth angle" and "Rear left azimuth angle != rear right azimuth angle", it means that the device is only obstructed from the rear. Therefore, it is only necessary to determine the rear obstruction situation, i.e.:

[0055] ① If "eleAngle < rear right azimuth angle", then the occlusion margin value is "rear right azimuth angle - eleAngle". This value is positive, and the target is located in the blank area on the right, with no occlusion.

[0056] ② If “Rear right azimuth <= eleAngle <= rear left azimuth”, then the occlusion margin is the larger of “Rear right azimuth - eleAngle” and “eleAngle - rear left azimuth”. If this value is negative, the target is located in the rear occlusion area.

[0057] ③ If "eleAngle > rear left azimuth angle", then the occlusion margin value is "eleAngle - rear left azimuth angle", and this value is positive, indicating that the target is in the rear blank area.

[0058] (2) If in the occlusion angle data, "front left azimuth angle!= front right azimuth angle" and "rear left azimuth angle == rear right azimuth angle", it means that there is only occlusion in the front of the device. Then, only the front occlusion situation needs to be judged, that is:

[0059] ① If "eleAngle <= front right azimuth angle", then the occlusion margin value is "eleAngle – front right azimuth angle", and this value is negative, indicating that the target is in the right front occlusion area;

[0060] ② If "front right azimuth angle < eleAngle < front left azimuth angle", then the occlusion margin value is the smaller value between "eleAngle – front right azimuth angle" and "front left azimuth angle - eleAngle", and this value is positive, indicating that the target is in the blank area;

[0061] ③ If "eleAngle > front left azimuth angle", then the occlusion margin value is "front left azimuth angle – eleAngle", and this value is negative, indicating that the target is in the left front occlusion area.

[0062] (3) If in the occlusion angle data, "front left azimuth angle!= front right azimuth angle" and "rear left azimuth angle!= rear right azimuth angle", it means that there is occlusion in both the front and rear of the device. Then, the occlusion situations in both the front and rear need to be judged simultaneously, that is:

[0063] ① If "eleAngle <= front right azimuth angle", then the occlusion margin value is "eleAngle – front right azimuth angle", and this value is negative, indicating that the target is in the right front occlusion area;

[0064] ② If "front right azimuth angle < eleAngle < rear right azimuth angle", then the occlusion margin value is the smaller value between "eleAngle – front right azimuth angle" and "rear right azimuth angle - eleAngle", and this value is positive, indicating that the target is in the blank area;

[0065] ③ If "rear right azimuth angle <= eleAngle <= rear left azimuth angle", then the occlusion margin value is the larger value between "rear right azimuth angle - eleAngle" and "eleAngle - rear left azimuth angle", and this value is negative, indicating that the target is in the rear occlusion area;

[0066] ④ If "rear left azimuth angle < eleAngle < front left azimuth angle", then the occlusion margin value is the smaller value between "eleAngle – rear left azimuth angle" and "front left azimuth angle - eleAngle", and this value is positive, indicating that the target is in the blank area;

[0067] ⑤ If “eleAngle>= front left azimuth angle”, then the occlusion margin value is “front left azimuth angle – eleAngle”. This value is negative, and the target is located in the left front occlusion area.

[0068] In addition to the above embodiments, the present invention also includes other embodiments. All technical solutions formed by equivalent transformation or equivalent substitution should fall within the protection scope of the claims of the present invention.

Claims

1. A method for real-time calculation and two-dimensional display of a shipborne antenna device obscuration margin, characterized in that The method comprises the following steps: Step A, Database Design: This includes the interrelated "Antenna Obstruction Area Description Table," "Antenna Equipment Identification Table," and "Ship Attitude and Position Data Table." The database tables are read according to a specific order and rules, and the data in the database tables is checked for validity. Specifically, this includes: 1) Reading the "Antenna Obstruction Area Description Table" by "Antenna Identification Number," simultaneously sorting it by elevation angle from smallest to largest, generating an array of obstruction areas for each antenna, forming data in the following format: {Antenna Identification Number, [Forward Left Azimuth, Forward Right Azimuth, Rear Right Azimuth, Rear Left Azimuth, Elevation Angle]} + The "+" sign indicates that there are multiple sets of data. 2) reading the "antenna device identification table" in order from small to large according to "antenna identification number", converting the "antenna data identification code" therein from hexadecimal to decimal; according to the "ship attitude and position identification number" therein, reading the corresponding record from the "ship attitude and position data table", and associating the "ship attitude and position device identification code" with the "antenna identification number"; The size relationship of the azimuth angle is: Front left azimuth angle ≤ front right azimuth angle ≤ rear right azimuth angle ≤ rear left azimuth angle; Step B, display screen design: including overall view and device view, which are complementary to each other, the overall view is used for real-time observation of the linkage change of the heading and the azimuth angle, the elevation angle and the shielding margin of each device, and the conclusion of whether the ship turning is reasonable can be directly obtained; the device view is used for monitoring whether the device falls into and avoids the shadow area in the whole monitoring arc segment; Step C, shielding margin calculation: (1) using the top-down projection coordinate system, the shielding area of a single device and the projection curve of the device pointing axis are drawn; (2) using a 360° dial to draw the azimuth angle of the device, the azimuth indicating line drawn from the center of the dial indicates the actual azimuth angle of the device, and the radial length of the indicating line indicates the actual elevation angle of the device; (3) the radial direction of the dial represents the elevation angle, the elevation angle gradually increases from the center of the dial, and the 0° elevation angle is at 1 / 2 of the radial length; the shielding margin is calculated by using the elevation angle of the current device and the elevation angle and azimuth angle of the shielding area array; Step D, two-dimensional display of data: the received data is time-stamped and aligned, the shielding margin of each device is uniformly calculated at the whole second point, and the shielding margin is displayed in real time on the overall view and the device view; if the shielding margin is too small or has a negative trend, an alarm will be prompted on the interface and a turning suggestion will be given.

2. The method for calculating and displaying the shielding margin of a shipborne antenna equipment in real time according to claim 1, characterized in that: The "antenna shielding area description table" comprises seven fields, the field "area identification number" is the primary key, each shielding area is configured with an identification number, the same antenna can have multiple "area identification numbers", and the several areas jointly form the shielding area of the antenna; each shielding area is composed of the fields "front left azimuth angle", "front right azimuth angle", "rear right azimuth angle", "rear left azimuth angle" and "elevation angle", and the field "antenna identification number" is the foreign key and is used for pointing to the "antenna device identification table"; The "antenna device identification table" stores the basic information of the antenna device of the measurement platform, including the antenna identification number, the antenna name, the antenna data identification code, whether to calculate and the ship attitude and position identification number, wherein the field "antenna data identification code" is used to identify the azimuth and elevation data of the antenna from the network data; the field "ship attitude and position identification number" is the foreign key and points to the "ship attitude and position data table", and is used to specify the ship attitude and position device matched with the antenna; The "ship attitude and position data table" stores the basic information of the ship attitude and position device, and when there are multiple sets of ship attitude and position measurement devices, the data of one set of measurement devices is selected for actual calculation, including the "ship attitude and position identification number" as the primary key, the "ship attitude and position device name" and the "ship attitude and position device identification code".

3. The method for real-time calculation and two-dimensional display of obstruction margin of shipborne antenna equipment according to claim 1, characterized in that... The whole view in step B includes counting the number of records with the field "whether to calculate" as TRUE in the "antenna equipment identification table", and drawing the shielding margin diagram of each equipment in the left part of the view in ascending order of "antenna identification number"; the right part of the view displays the heading information of the measurement platform, the azimuth data, the elevation data and the shielding margin data of each equipment.

4. The method for real-time calculation and two-dimensional display of obstruction margin of shipborne antenna equipment according to claim 1, characterized in that... The number of the sub-equipment views in step B is consistent with the number of the shielding margin diagrams in the whole view, each sub-equipment view is different only in equipment data and shielding data, and the display mode is completely consistent, according to the data of the equipment in the "antenna shielding area description table", the shielding area of a single equipment and the projection curve of the equipment pointing axis are drawn in the top view coordinate system; a 360° dial is drawn to express the azimuth angle of the equipment, the azimuth indicating line drawn from the center of the dial indicates the actual azimuth angle of the equipment, the radial length of the indicating line indicates the actual elevation angle of the equipment, which is initialized as 0°; the radial scale of the dial is drawn to express the elevation angle of the equipment, and the reference circle of 0° elevation angle is drawn at 1 / 2 of the radial length.

5. The method for real-time calculation and two-dimensional display of obstruction margin of shipborne antenna equipment according to claim 1, characterized in that... On the ship TT&C data service network, two types of data are collected according to the communication protocol: ①the original measurement data of the TT&C equipment, from which the azimuth angle and the elevation angle of the equipment under the deck system are extracted; ②the ship attitude and position data of the inertial navigation equipment, from which the current ship position, heading and speed information are obtained.

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