Aircraft track calculation method based on periodic coordinate system transformation

Abstract

The embodiment of the invention provides an aircraft track calculation method based on stage coordinate system transformation. The method comprises the following steps: setting task parameters, and setting a driving plan of a ship, a route point set of an aircraft task execution stage and a standard route point set of a recovery landing stage; setting an absolute coordinate system and a relative coordinate system; the method comprises the following steps: calculating a flight path in a takeoff stage, recording a current position of a ship as an original point of a relative coordinate system when the aircraft takes off, initializing position information of the aircraft, and calculating a corresponding distance of the aircraft flying at a set speed within a set time interval based on the relative coordinate system; converting latitude and longitude coordinates of the aircraft in a relative position absolute coordinate system according to the real-time position of the ship; transition from a take-off stage to a task execution stage is carried out; calculating a task execution stage track; transition from a task execution stage to a recovery landing stage is carried out; and calculating the flight path of the recovery landing stage, and determining the flight segment of the recovery landing stage of the aircraft, so that the aircraft lands on the ship.

Description

Technical Field

[0001] The invention relates to the technical field of aviation control, and in particular to an aircraft track calculation method based on staged coordinate system transformation. Background Art

[0002] With the development of aviation technology, more and more flight missions require accurate trajectory calculation to ensure flight safety and efficiency. Especially in the field of air traffic control, aircraft need to go through multiple stages during the mission, including taking off from the ship, performing flight missions, and recovery landing. This series of actions puts forward strict requirements on trajectory calculation, especially when switching between different flight stages.

[0003] Traditional aircraft trajectory calculation methods usually rely on absolute means such as the Global Positioning System (GPS), using a single absolute coordinate system to calculate the position, heading and other information of the aircraft. However, this method has obvious limitations:

[0004] 1. High computational complexity: During the entire flight process, especially during the recovery phase, the iterative calculation of the trajectory using relative coordinates to absolute coordinates for all waypoint sets will greatly increase the computational complexity, resulting in waste and excessive consumption of resources, and high CPU usage.

[0005] 2. Low result accuracy: During the recovery phase, the aircraft needs to wait for the standard route corresponding to the spacecraft; during the landing phase, the aircraft needs to align with the position of the ship. When the ship is in motion, the position of the standard waiting route corresponding to it changes dynamically relative to the aircraft. The track calculation based only on absolute coordinates is difficult to accurately reflect the relative position relationship between the aircraft and the landing platform. The accuracy of the track calculation result is reduced, which increases the landing risk.

[0006] 3. Lack of flexibility: A single coordinate system cannot adapt to the characteristics of different flight phases, affecting the flexibility of track calculation and the accuracy of calculation results.

[0007] To overcome the above problems, a new track calculation method is needed, which can flexibly switch the coordinate system according to the characteristics of different flight phases. Summary of the invention

[0008] In view of the above problems existing in the prior art, an embodiment of the present invention provides an aircraft track calculation method based on staged coordinate system transformation, which is particularly suitable for the case where the aircraft takes off from a ship and returns to land after completing the mission. The method optimizes the aircraft track calculation process by adopting different coordinate system transformation strategies in different flight stages, thereby improving the calculation efficiency and accuracy.

[0009] An embodiment of the present invention provides an aircraft track calculation method based on phased coordinate system transformation, comprising:

[0010] Step 1: Set the mission parameters, including the ship's travel plan, the waypoint set for the aircraft's mission execution phase, and the standard route point set for the recovery and landing phase;

[0011] Step 2: Set the coordinate system, including setting the absolute coordinate system and the relative coordinate system;

[0012] Step 3: Calculate the takeoff track, record the current position of the ship when the aircraft takes off, as the origin (0,0) of the relative coordinate system, initialize the position information of the aircraft, calculate the corresponding distance flown by the aircraft at the set speed within the set time interval based on the relative coordinate system, and convert the latitude and longitude coordinates of the relative position of the aircraft in the absolute coordinate system according to the real-time position of the ship;

[0013] Step 4: Transition from the takeoff phase to the mission execution phase, and determine the flight segment of the aircraft between the takeoff phase and the mission execution phase;

[0014] Step 5: Calculate the mission execution phase trajectory and determine the flight segment of the aircraft during the mission execution phase;

[0015] Step 6: Transition from the mission execution phase to the recovery and landing phase, and determine the flight segment of the aircraft from the mission execution phase to the recovery and landing phase;

[0016] Step 7: Calculate the recovery and landing phase trajectory and determine the recovery and landing segment of the aircraft so that the aircraft can land on the ship.

[0017] In some embodiments of the present invention, in step 1, the method specifically includes:

[0018] Step 11: According to the mission requirements, set the ship's travel plan, including the latitude and longitude of the ship's starting and ending points, and the speed;

[0019] Step 12: Set the waypoint set for the aircraft mission execution phase. The attributes of each point in the waypoint base include the absolute position of the point, the altitude and speed that should be reached when reaching the point;

[0020] Step 13: Set the standard route point set for the recovery landing phase. The attributes of each point in the standard route point set include the relative position of the point, specifically the distance and direction relative to the ship, and the height and speed that should be reached when reaching the point;

[0021] If there is an arc between two waypoints, the attributes of the previous point also include the position of the turning center point, specifically the distance and direction relative to the ship, the turning radius, and the turning arc.

[0022] In some embodiments of the present invention, in step 2, the method specifically includes:

[0023] Step 21: When setting the absolute coordinate system, the World Geodetic System 1984 coordinate system is used as the absolute coordinate system for the trajectory calculation of the aircraft during the mission execution phase;

[0024] Step 22: When setting the relative coordinate system, take the real-time position of the ship as the origin and establish a plane rectangular coordinate system as the relative coordinate system for trajectory calculation during takeoff and recovery and landing phases.

[0025] In some embodiments of the present invention, in step 3, the method specifically includes:

[0026] Step 31: After receiving the take-off command, the aircraft takes off from the ship and records the current position of the ship as the origin (0,0) of the relative coordinate system;

[0027] Step 32: Using the ship's starting position as the take-off point, initialize the aircraft's position information;

[0028] Step 33: Set the time interval to 1 second, and calculate the corresponding distance that the aircraft flies at the set speed within the time interval based on the relative coordinate system;

[0029] Step 34: According to the real-time position of the ship, the relative position of the aircraft is converted into longitude and latitude coordinates in the absolute coordinate system, and the position of the ship is updated according to the speed of the ship.

[0030] In some embodiments of the present invention, in step 4, the method specifically includes:

[0031] Step 41: When the aircraft flies to a distance of 20 kilometers from the ship, the absolute coordinates of the aircraft's take-off point and the current point are calculated based on the position of the ship, and the take-off point and the current point represent the first flight segment of the aircraft;

[0032] Step 42: Switch the relative coordinate system to the absolute coordinate system, and form the second segment of the aircraft to be flown according to the end point in the first segment and the first waypoint in the mission execution phase, and calculate the headings of the first segment and the second segment. If the headings are different, an arc segment is generated as a transition between the two segments according to the pressure point turning method;

[0033] Step 43: Calculate the arc length, arc angle, radius and latitude and longitude of the turning arc according to the heading of the first flight segment, the heading of the second flight segment and the longitude and latitude of the three points;

[0034] Step 44: Set the time interval to every second, convert the longitude and latitude into Mercator projection, calculate the corresponding distance that the aircraft flies at a certain speed within the time interval based on the absolute coordinate system, obtain the Mercator projection coordinates of the next point, and then convert it into longitude and latitude to obtain the next position of the aircraft;

[0035] Step 45: Continue along the segment in this manner, completing the turning arc and the second straight segment.

[0036] In some embodiments of the present invention, in step 5, the method specifically includes:

[0037] Step 51: In the mission execution phase, according to the mission waypoint set, a sliding window method is used to select three consecutive waypoints each time to calculate the parameters including heading and distance in the current segment and the next segment;

[0038] Step 52: If the headings are inconsistent, a turning arc is generated according to the pressure point turning method, and the arc length, arc angle, radius and longitude and latitude of the turning center of the turning arc are calculated;

[0039] Step 53: If the heading is consistent, continue flying along the straight segment;

[0040] Step 54: convert the longitude and latitude of the current position of the aircraft into Mercator projection coordinates, fly the corresponding distance according to the set time interval and the current speed of the aircraft, advance to the next point along the flight segment, and calculate and update the Mercator projection of the aircraft;

[0041] Step 55: Convert the updated Mercator projection coordinates into longitude and latitude coordinates as the next position of the aircraft;

[0042] Step 56: If the current flight segment is not completed, continue to move forward along the current flight segment; if the current flight segment is completed, the sliding window moves forward one point, and steps 51 to 55 are repeated to generate subsequent tracks until the mission phase flight is completed.

[0043] In some embodiments of the present invention, in step 6, the method specifically includes:

[0044] Step 61: After the aircraft completes the mission, the next flight segment of the aircraft is formed according to the end point of the mission execution phase and the first waypoint of the recovery and landing phase, and the heading is calculated;

[0045] If it is different from the last segment of the mission execution phase, an arc segment is generated as a transition between the two segments according to the pressure point turning method;

[0046] Step 62: When the aircraft reaches the end of the turning arc, the absolute coordinates of the aircraft are converted into relative coordinates according to the real-time position of the ship, the distance and direction of the aircraft relative to the ship are calculated, and the relative coordinate system is switched. At this time, the position of the aircraft can be regarded as the first waypoint of the recovery landing phase.

[0047] In some embodiments of the present invention, in step 7, the method specifically includes:

[0048] Step 71: Based on the previous waypoint and the preset standard route point set for the recovery and landing stage, a complete waypoint set for the recovery and landing stage is formed;

[0049] Step 72: In this stage, based on the relatively comprehensive attribute information of the points, the method of forming a flight segment with two points is adopted to directly determine whether the current flight segment is a straight line or an arc, and the flight segment information including the length and heading is calculated;

[0050] Step 73: Set the time interval to every second, and calculate the new position of the aircraft after it flies a certain distance within the time interval based on the relative coordinate system;

[0051] Step 74: converting the calculated relative position into longitude and latitude in an absolute coordinate system to represent the specific position information of the aircraft;

[0052] Step 75: If the current flight segment is completed, move forward one point and repeat steps 72 to 74 to generate a subsequent track until the recovery and landing phase of the flight is completed and the aircraft lands on the ship.

[0053] Compared with the prior art, the beneficial effects of the aircraft track calculation method based on the staged coordinate system transformation provided by the embodiment of the present invention are: it improves the calculation efficiency: by using absolute coordinates to calculate the track in the mission stage and using relative coordinates to calculate the track in the recovery stage, the calculation complexity is significantly reduced, thereby improving the overall calculation efficiency; enhanced flexibility and accuracy: by automatically switching the coordinate system according to the different stages of the flight, the flexibility of the track calculation is improved, so that the track calculation is more in line with the actual flight requirements. In the mission execution stage, the absolute coordinate calculation is used to ensure the accuracy of the aircraft position; in the recovery and landing stages, the relative coordinate calculation is used to achieve high-precision landing guidance, and the accuracy of the calculation results is improved; error accumulation is reduced: for long-distance flight missions, the use of a relative coordinate system in the recovery stage can effectively reduce the position error caused by long-term accumulation. In summary, the present invention effectively solves the problems existing in the traditional track calculation method by introducing the staged coordinate system transformation, and has significant advantages in terms of calculation efficiency, flexibility and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A flow chart of an aircraft track calculation method based on phased coordinate system transformation provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0055] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0056] Various aspects and features of the present application are described herein with reference to the accompanying drawings.

[0057] These and other characteristics of the present application will become apparent from the following description of a preferred form of embodiment given as a non-limiting example with reference to the accompanying drawings.

[0058] It should also be understood that, although the present application has been described with reference to some specific examples, those skilled in the art will be able to realize many other equivalent forms of the present application that have the features described in the claims and are therefore within the scope of protection defined thereby.

[0059] The above and other aspects, features and advantages of the present application will become more apparent in view of the following detailed description when taken in conjunction with the accompanying drawings.

[0060] Specific embodiments of the present application are described hereinafter with reference to the accompanying drawings; however, it should be understood that the embodiments applied for are merely examples of the present application, which may be implemented in a variety of ways. Well-known and / or repeated functions and structures are not described in detail to determine the true intent based on the user's historical operations and to avoid unnecessary or redundant details that make the present application unclear. Therefore, the specific structural and functional details applied for herein are not intended to be limiting, but are merely used as the basis and representative basis for the claims to teach those skilled in the art to use the present application in a variety of ways with substantially any suitable detailed structure.

[0061] This specification may use the phrases "in one embodiment," "in another embodiment," "in yet another embodiment," or "in other embodiments," all of which may refer to one or more of the same or different embodiments according to the present application.

[0062] The embodiment of the present invention provides a method for calculating the trajectory of an aircraft based on phased coordinate system transformation, such as Figure 1 As shown, the calculation method includes:

[0063] Step 1: Set the mission parameters, including the ship's travel plan, the waypoint set for the aircraft's mission execution phase, and the standard route point set for the recovery and landing phase;

[0064] Step 2: Set the coordinate system, including setting the absolute coordinate system and the relative coordinate system;

[0065] Step 3: Calculate the takeoff track, record the current position of the ship when the aircraft takes off, as the origin (0,0) of the relative coordinate system, initialize the position information of the aircraft, calculate the corresponding distance flown by the aircraft at the set speed within the set time interval based on the relative coordinate system, and convert the latitude and longitude coordinates of the relative position of the aircraft in the absolute coordinate system according to the real-time position of the ship;

[0066] Step 4: Transition from the takeoff phase to the mission execution phase, and determine the flight segment of the aircraft between the takeoff phase and the mission execution phase;

[0067] Step 5: Calculate the mission execution phase trajectory and determine the flight segment of the aircraft during the mission execution phase;

[0068] Step 6: Transition from the mission execution phase to the recovery and landing phase, and determine the flight segment of the aircraft from the mission execution phase to the recovery and landing phase;

[0069] Step 7: Calculate the recovery and landing phase trajectory and determine the recovery and landing segment of the aircraft so that the aircraft can land on the ship.

[0070] The technical solution is as follows:

[0071] 1. Flight Phase Division

[0072] First, three different flight phases are defined: takeoff phase, mission execution phase, and recovery and landing phase. The takeoff phase refers to the process of the aircraft taking off from the ship and flying to a certain distance from the ship; the mission execution phase refers to the process of the aircraft performing flight missions such as reconnaissance and transportation according to the predetermined route after leaving the takeoff phase; the recovery and landing phase refers to the process of the aircraft completing the mission and preparing to return to wait and land.

[0073] 2. Coordinate system selection

[0074] Set the coordinate system selection at different stages. In the mission execution stage, the absolute coordinate system is used to calculate the trajectory of the aircraft. This stage mainly focuses on the position and motion state of the aircraft in the wide space. In the takeoff and recovery landing stages, the relative coordinate system is used for trajectory calculation. The position of the aircraft is updated in real time as the ship moves, simplifying the calculation complexity.

[0075] 3. Track Calculation

[0076] During the takeoff phase, the aircraft uses the location of the ship as the starting point to initialize its position information. Based on the relative coordinate system, the distance and direction relative to the ship after a certain time interval are calculated, and then the latitude, longitude and heading of the aircraft are calculated based on the location of the ship.

[0077] During the mission execution phase, in the form of a sliding window, two straight segments are formed each time according to three consecutive points in the waypoint set as the current segment and the next segment, and their heading, distance and other parameter information are calculated. If the headings of the two segments are inconsistent, the pressure point turning method is set to calculate the arc length, radius, and turning center of the arc segment. At this time, the three points form a three-segment segment of [straight line, arc, straight line]. Based on the absolute coordinate system, the longitude and latitude of the aircraft's location are converted into Mercator projection, and the corresponding distance is advanced along the segment at a certain time interval. The Mercator projection position of the next point is calculated based on the Mercator projection position, forward distance and heading of the previous point, and then the Mercator projection is converted into longitude and latitude to obtain the longitude and latitude position of the next point. When the flight of the segment ends, the sliding window advances one point, and the segment is iteratively generated and the track is calculated in the same way again.

[0078] During the recovery and landing phase, the track is calculated based on the relative coordinate system, just like during the takeoff phase. The position information of the standard route is expressed as the distance and azimuth relative to the ship, and the position information of the aircraft is also expressed as the two-dimensional projection coordinates converted from the distance and azimuth from the ship. In the relative coordinate system, the position after advancing a certain distance within a certain time interval is calculated based on the current position of the aircraft (the two-dimensional projection coordinates of the distance and azimuth), and then converted into the distance and azimuth from the ship, so as to calculate the longitude and latitude of the aircraft based on the longitude and latitude of the ship.

[0079] 4. Transition Processing between Phases

[0080] A smooth transition mechanism from relative coordinates to absolute coordinates is set up between the take-off phase and the mission execution phase, and a smooth transition mechanism from absolute coordinates to relative coordinates is set up between the mission execution phase and the recovery phase to ensure the continuity and stability of the coordinate system during transformation.

[0081] To facilitate understanding of the above technical solution, the following is a detailed description with reference to the accompanying drawings, as follows:

[0082] Figure 1 It is the overall flow chart of the technical solution of the present invention, combined with Figure 1 The specific implementation of the aircraft track calculation method based on phased coordinate system transformation proposed in the above embodiment of the present invention is as follows:

[0083] Step 1: Set task parameters

[0084] Step 11: Set the ship's travel plan according to the mission requirements, that is, the latitude and longitude of the ship's starting and ending points, and the speed;

[0085] Step 12, set the waypoint set for the aircraft mission execution phase, and the attributes of each point include the absolute position of the point, i.e., longitude and latitude, and the altitude and speed that should be reached when reaching the point;

[0086] Step 13, set the standard route point set for the recovery and landing phase. The attributes of each point include the relative position of the point, i.e., the distance and direction relative to the ship, the altitude and speed that should be achieved when reaching the point. If there is an arc between two waypoints, the attributes of the previous point should also include the position of the turning center point, i.e., the distance and direction relative to the ship, the turning radius, and the turning arc.

[0087] Step 2: Coordinate system setting

[0088] Step 21, absolute coordinate system: adopt WGS84 (World Geodetic System 1984) coordinate system as the absolute coordinate system for the trajectory calculation of the aircraft during the mission execution phase;

[0089] Step 22, the relative coordinate system takes the real-time position of the ship as the origin, and establishes a plane rectangular coordinate system as the relative coordinate system, which is used for trajectory calculation during the take-off and recovery landing phases.

[0090] Step 3: Takeoff phase trajectory calculation

[0091] Step 31, after receiving the take-off command, the aircraft takes off from the ship and records the current position of the ship as the origin (0,0) of the relative coordinate system;

[0092] Step 32, using the ship's starting position as the take-off point, initialize the aircraft's position information. The distance relative to the ship is 0, the orientation relative to the ship is 0, the heading is the ship's current heading, the speed is 450 km / h, and the altitude is 300 meters;

[0093] Step 33, setting the time interval to every second, and calculating the corresponding distance that the aircraft flies at a certain speed within the time interval based on the relative coordinate system;

[0094] Step 34, based on the real-time position (latitude and longitude) of the ship, the relative position (distance and orientation) of the aircraft is converted into latitude and longitude coordinates in an absolute coordinate system. At the same time, the position of the ship is updated based on the speed of the ship.

[0095] Step 4: Transition from takeoff phase to mission execution phase

[0096] Step 41, when the aircraft flies to a distance of 20 kilometers from the ship, the absolute coordinates of the aircraft's take-off point and the current point, i.e., longitude and latitude, are calculated based on the position of the ship. These two points also represent the first leg of the aircraft's flight;

[0097] Step 42, switch the relative coordinate system to the absolute coordinate system, and form the second segment of the aircraft to be flown according to the end point in the first segment and the first waypoint in the mission execution phase. Calculate the headings of the first segment and the second segment. If the headings are different, generate an arc segment as a transition between the two segments according to the pressure point turning method;

[0098] Step 43, calculating the arc length, arc angle, radius and latitude and longitude of the turning arc segment according to the heading of the first flight segment, the heading of the second flight segment and the longitude and latitude of the three points;

[0099] Step 44, set the time interval to every second, convert the longitude and latitude into Mercator projection, calculate the corresponding distance that the aircraft flies at a certain speed within the time interval based on the absolute coordinate system, obtain the Mercator projection coordinates of the next point, and then convert it into longitude and latitude to obtain the next position of the aircraft.

[0100] Step 45, proceed along the segment in this manner to complete the flight of the turning arc segment and the second straight segment.

[0101] Step 5: Track calculation during mission execution

[0102] Step 51, in the mission execution phase, according to the mission waypoint set, a sliding window method is used to select three consecutive waypoints each time to calculate the heading, distance and other parameters of the current segment and the next segment;

[0103] Step 52, if the headings are inconsistent, a turning arc is generated according to the pressure point turning method, and the arc length, arc, radius and longitude and latitude of the turning center of the turning arc are calculated;

[0104] Step 53, if the heading is consistent, continue flying along the straight segment;

[0105] Step 54, converting the longitude and latitude of the current position of the aircraft into Mercator projection coordinates, flying a corresponding distance according to the set time interval and the current speed of the aircraft, advancing along the flight segment to the next point, and calculating and updating the Mercator projection of the aircraft;

[0106] Step 55, converting the updated Mercator projection coordinates into longitude and latitude coordinates as the next position of the aircraft;

[0107] Step 56, if the current flight segment is not completed, continue to move forward along the current flight segment; if the current flight segment is completed, the sliding window moves forward one point, and steps 51 to 55 are repeated to generate subsequent tracks until the mission phase flight ends.

[0108] Step 6: Transition from mission execution to recovery and landing

[0109] Step 61, after the aircraft completes the mission, the aircraft calculates the heading of the next segment to be flown based on the end point of the mission execution phase and the first waypoint of the recovery and landing phase. If it is different from the last segment of the mission execution phase, an arc segment is generated as a transition between the two segments according to the pressure point turning method;

[0110] Step 62, when the aircraft reaches the end of the turning arc, the absolute coordinates of the aircraft are converted into relative coordinates according to the real-time position of the ship, the distance and orientation of the aircraft relative to the ship are calculated, and the relative coordinate system is switched. At this time, the position of the aircraft can be regarded as the first waypoint of the recovery landing stage;

[0111] Step 7: Calculation of trajectory during recovery and landing phase

[0112] Step 71, forming a complete waypoint set for the recovery and landing phase according to the previous waypoint and the preset standard waypoint set for the recovery and landing phase;

[0113] Step 72, in this stage, based on the relatively comprehensive attribute information of the points, the method of forming a flight segment with two points is adopted to directly determine whether the current flight segment is a straight line or an arc, and calculate the length, heading and other information of the flight segment;

[0114] Step 73, setting the time interval to every second, and calculating the new position (distance and orientation) of the aircraft after it flies a certain distance within the time interval based on the relative coordinate system;

[0115] Step 74, converting the calculated relative position into longitude and latitude in an absolute coordinate system to represent the specific position information of the aircraft;

[0116] Step 75, if the current flight segment is completed, move forward one point and repeat steps 72 to 74 to generate a subsequent track until the recovery and landing phase of the flight is completed and the aircraft lands accurately on the ship.

[0117] It can be known from the above technical scheme that the beneficial effect of the aircraft track calculation method based on the staged coordinate system transformation provided by the above embodiment of the present invention is that: it improves the calculation efficiency: by using absolute coordinates to calculate the track in the mission stage and using relative coordinates to calculate the track in the recovery stage, the calculation complexity is significantly reduced, thereby improving the overall calculation efficiency; enhance flexibility and accuracy: by automatically switching the coordinate system according to the different stages of the flight, the flexibility of the track calculation is improved, so that the track calculation is more in line with the actual flight requirements. In the mission execution stage, the absolute coordinate calculation is used to ensure the accuracy of the aircraft position; in the recovery and landing stages, the high-precision landing guidance is achieved through the relative coordinate calculation, which improves the accuracy of the calculation results; reduces error accumulation: for long-distance flight missions, the use of a relative coordinate system in the recovery stage can effectively reduce the position error caused by long-term accumulation. In summary, the present invention effectively solves the problems existing in the traditional track calculation method by introducing the staged coordinate system transformation, and has significant advantages in terms of calculation efficiency, flexibility and accuracy.

[0118] The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A method for calculating an aircraft track based on staged coordinate system transformation, characterized in that: include: Step 1: Set the mission parameters, including the ship's travel plan, the waypoint set for the aircraft's mission execution phase, and the standard route point set for the recovery and landing phase; Step 2: Set the coordinate system, including setting the absolute coordinate system and the relative coordinate system; Step 3: Calculate the takeoff track, record the current position of the ship when the aircraft takes off as the origin of the relative coordinate system, initialize the position information of the aircraft, calculate the corresponding distance flown by the aircraft at the set speed within the set time interval based on the relative coordinate system, and convert the latitude and longitude coordinates of the relative position of the aircraft in the absolute coordinate system according to the real-time position of the ship; Step 4: Transition from the takeoff phase to the mission execution phase, and determine the flight segment of the aircraft between the takeoff phase and the mission execution phase; Step 5: Calculate the mission execution phase trajectory and determine the flight segment of the aircraft during the mission execution phase; Step 6: Transition from the mission execution phase to the recovery and landing phase, and determine the flight segment of the aircraft from the mission execution phase to the recovery and landing phase; Step 7: Calculate the recovery and landing phase trajectory and determine the recovery and landing segment of the aircraft so that the aircraft can land on the ship.

2. The method for calculating the flight path of an aircraft based on staged coordinate system transformation according to claim 1, characterized in that: In step 1, the method specifically includes: Step 11: According to the mission requirements, set the ship's travel plan, including the latitude and longitude of the ship's starting and ending points, and the speed; Step 12: Set the waypoint set for the aircraft mission execution phase. The attributes of each point in the waypoint base include the absolute position of the point, the altitude and speed that should be reached when reaching the point; Step 13: Set the standard route point set for the recovery landing phase. The attributes of each point in the standard route point set include the relative position of the point, specifically the distance and direction relative to the ship, and the height and speed that should be reached when reaching the point; If there is an arc between two waypoints, the attributes of the previous point also include the position of the turning center point, specifically the distance and direction relative to the ship, the turning radius, and the turning arc.

3. The method for calculating the flight path of an aircraft based on staged coordinate system transformation according to claim 2, characterized in that: In step 2, the method specifically includes: Step 21: When setting the absolute coordinate system, the World Geodetic System 1984 coordinate system is used as the absolute coordinate system for the trajectory calculation of the aircraft during the mission execution phase; Step 22: When setting the relative coordinate system, take the real-time position of the ship as the origin and establish a plane rectangular coordinate system as the relative coordinate system for trajectory calculation during takeoff and recovery and landing phases.

4. The method for calculating the flight path of an aircraft based on staged coordinate system transformation according to claim 3, characterized in that: In step 3, the method specifically includes: Step 31: After receiving the take-off command, the aircraft takes off from the ship and records the current position of the ship as the origin of the relative coordinate system; Step 32: Using the ship's starting position as the take-off point, initialize the aircraft's position information; Step 33: Set the time interval to 1 second, and calculate the corresponding distance that the aircraft flies at the set speed within the time interval based on the relative coordinate system; Step 34: According to the real-time position of the ship, the relative position of the aircraft is converted into longitude and latitude coordinates in the absolute coordinate system, and the position of the ship is updated according to the speed of the ship.

5. The method for calculating the flight path of an aircraft based on staged coordinate system transformation according to claim 4, characterized in that: In step 4, the method specifically includes: Step 41: When the aircraft flies to a distance of 20 kilometers from the ship, the absolute coordinates of the aircraft's take-off point and the current point are calculated based on the position of the ship, and the take-off point and the current point represent the first flight segment of the aircraft; Step 42: Switch the relative coordinate system to the absolute coordinate system, and form the second segment of the aircraft to be flown according to the end point in the first segment and the first waypoint in the mission execution phase, and calculate the headings of the first segment and the second segment. If the headings are different, an arc segment is generated as a transition between the two segments according to the pressure point turning method; Step 43: Calculate the arc length, arc angle, radius and latitude and longitude of the turning arc according to the heading of the first flight segment, the heading of the second flight segment and the longitude and latitude of the three points; Step 44: Set the time interval to every second, convert the longitude and latitude into Mercator projection, calculate the corresponding distance that the aircraft flies at a certain speed within the time interval based on the absolute coordinate system, obtain the Mercator projection coordinates of the next point, and then convert it into longitude and latitude to obtain the next position of the aircraft; Step 45: Continue along the segment in this manner, completing the turning arc and the second straight segment.

6. The method for calculating the flight path of an aircraft based on staged coordinate system transformation according to claim 5, characterized in that: In step 5, the method specifically includes: Step 51: In the mission execution phase, according to the mission waypoint set, a sliding window method is used to select three consecutive waypoints each time to calculate the parameters including heading and distance in the current segment and the next segment; Step 52: If the headings are inconsistent, a turning arc is generated according to the pressure point turning method, and the arc length, arc angle, radius and longitude and latitude of the turning center of the turning arc are calculated; Step 53: If the heading is consistent, continue flying along the straight segment; Step 54: convert the longitude and latitude of the current position of the aircraft into Mercator projection coordinates, fly the corresponding distance according to the set time interval and the current speed of the aircraft, advance to the next point along the flight segment, and calculate and update the Mercator projection of the aircraft; Step 55: Convert the updated Mercator projection coordinates into longitude and latitude coordinates as the next position of the aircraft; Step 56: If the current flight segment is not completed, continue to move forward along the current flight segment; if the current flight segment is completed, the sliding window moves forward one point, and steps 51 to 55 are repeated to generate subsequent tracks until the mission phase flight is completed.

7. The method for calculating the flight path of an aircraft based on staged coordinate system transformation according to claim 6, characterized in that: In step 6, the method specifically includes: Step 61: After the aircraft completes the mission, the next flight segment of the aircraft is formed according to the end point of the mission execution phase and the first waypoint of the recovery and landing phase, and the heading is calculated; If it is different from the last segment of the mission execution phase, an arc segment is generated as a transition between the two segments according to the pressure point turning method; Step 62: When the aircraft reaches the end of the turning arc, the absolute coordinates of the aircraft are converted into relative coordinates according to the real-time position of the ship, the distance and direction of the aircraft relative to the ship are calculated, and the relative coordinate system is switched. At this time, the position of the aircraft can be regarded as the first waypoint of the recovery landing phase.

8. The method for calculating the flight path of an aircraft based on staged coordinate system transformation according to claim 7, characterized in that: In step 7, the method specifically includes: Step 71: Based on the previous waypoint and the preset standard route point set for the recovery and landing stage, a complete waypoint set for the recovery and landing stage is formed; Step 72: In this stage, based on the relatively comprehensive attribute information of the points, the method of forming a flight segment with two points is adopted to directly determine whether the current flight segment is a straight line or an arc, and the flight segment information including the length and heading is calculated; Step 73: Set the time interval to every second, and calculate the new position of the aircraft after it flies a certain distance within the time interval based on the relative coordinate system; Step 74: converting the calculated relative position into longitude and latitude in an absolute coordinate system to represent the specific position information of the aircraft; Step 75: If the current flight segment is completed, move forward one point and repeat steps 72 to 74 to generate a subsequent track until the recovery and landing phase of the flight is completed and the aircraft lands on the ship.

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