A small area single machine grid search flight path planning method

Abstract

This invention discloses a method for planning flight paths for a single-aircraft search in a small area using a grid-like structure. Given a search area at a given time, a single-aircraft grid-like search model is established in a plane based on kinematic equations and the principles of plane geometry. Using plane geometry methods, and considering visibility and helicopter flight characteristics, the key waypoints of the search helicopter are planned, thus obtaining a complete search route. This method overcomes the shortcomings of slow speed and low accuracy of manual estimation, transforming the search application problem into a simple and intuitive geometric problem. It features easy implementation via computer programming, high accuracy, and good real-time performance, meeting the accuracy and effectiveness requirements of ground target search missions. This method is particularly suitable for helicopter command systems used in ground target reconnaissance or search and rescue applications.

Description

Technical Field

[0001] This invention relates to a method for planning a single-aircraft grid-shaped search route in a small area, which is used to realize the action planning of helicopter reconnaissance and search for targets in a small area. It is particularly suitable for helicopter command systems to formulate reconnaissance and search and rescue missions against ground targets. Background Technology

[0002] Ground target reconnaissance or search and rescue is a typical mission for helicopters. Upon receiving a target reconnaissance and search mission, it is necessary to estimate the number of reconnaissance and search helicopters required and plan flight routes based on the size of the area. Large areas typically require multi-aircraft coordinated reconnaissance, while smaller areas are handled by single-aircraft reconnaissance. The aim is to achieve efficient search coverage of the mission area, leaving no area unsearched while minimizing flight costs. Currently, this mainly relies on navigators' map work, manual measurement, or rough estimations based on experience. This method is slow and inaccurate, failing to meet the timeliness and accuracy requirements of modern combat or non-combat search and rescue operations. Summary of the Invention

[0003] This invention proposes a method for planning a small-area single-aircraft grid-shaped search for a known search area at a given moment. Based on the required search area length, width, and visibility distance, the method automatically plans a reciprocating flight path for the helicopter to cover the search area, and then calculates the navigation parameters. This method overcomes the inaccuracies and poor real-time performance of methods such as map manipulation calculations or manual estimations. It boasts advantages such as high accuracy, good real-time performance, and ease of automation by computer. It can meet the requirements of mission planning for the effectiveness and accuracy of small-area target reconnaissance and search operations, and can provide excellent auxiliary decision-making services for navigation personnel through automated planning.

[0004] The technical solution adopted in this invention is as follows:

[0005] A method for single-aircraft grid-shaped search route planning in a small area includes the following steps:

[0006] (1) Estimate the maximum length and maximum width of the search task area based on the target activity range to obtain a rectangular search area with a length of L1 and a width of L2;

[0007] (2) Based on the visibility d, the interval between each side of the search grid is determined to be 1.75 times the visibility distance. Then, the number of search sides required to search the entire area is N = L1 / (1.75d).

[0008] (3) Determine the search area entry point of the search helicopter based on the width of the rectangular search area and the current visibility d. That is, take the position 1.75d / 2 away from one end boundary on the long side of the rectangular search area as the entry point for the helicopter to fly into the search area, and then fly straight towards the turning point along the width direction.

[0009] (4) Turning flight at the turning point. The turning flight methods are as follows: The first method is to make a 90° turn at the turning point to the first leveling point, and then fly horizontally along the length direction for 1.75d-2r distance to the next turning point, and then make a 90° turn to the next leveling point, where r is the helicopter's aerial turning radius; The second method is to make a turn at the turning point with a turning diameter of 1.75 times the visibility, and make a turning flight with a turning slope of 180° to the next leveling point.

[0010] (5) Fly along the width direction to the next turning point from the next flat point, return to step ④, and exit the rectangular search area after completing the N edge search.

[0011] Complete the planning of single-aircraft grid-shaped search routes in a small area.

[0012] Furthermore, when entering and exiting the rectangular search area, the horizontal flight distance of the search edge in the width direction of the rectangular search area is L2-r, and the horizontal flight distance of the other search edges is L2-2r;

[0013] Where r = TAS × TAS / (g × tanβ), TAS = (W - Ucosf) / cosp;

[0014] In the formula, W is the helicopter's ground speed, U is the wind speed, f is the wind angle, p is the yaw angle, β is the helicopter's turning angle, and g is the local gravitational acceleration.

[0015] Furthermore, in step (4), if a 90° turn is adopted, then at the distance from the turning point... The first leveling point is located at the intersection of the long side and the long side along the length direction; if a 180° turn is adopted, the leveling point is located 1.75d away from the turn point along the length direction.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. The small-area single-aircraft grid-shaped search route planning method introduced in this invention, knowing the approximate area and visibility of the search target, uses plane geometry principles combined with the characteristics of helicopter flight to transform the search application problem into a simple mathematical problem that is clear and intuitive.

[0018] 2. This invention mainly adopts the planar geometry method, which is simple to implement in software programming and can be easily implemented automatically on a computer. It has a fast calculation speed and high accuracy. The calculation results can be directly provided to our aircraft as flight waypoints and flight parameters, which can meet the requirements of planning and precise command and guidance for rapid reconnaissance and search and rescue missions, and greatly improve the degree of automation of helicopter command system operations. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a 90° turn flight model for small-area single-aircraft grid-shaped search route planning according to the present invention.

[0020] Figure 2 This is a schematic diagram of a small-area single-aircraft grid-shaped search route planning 180° turn flight model. Detailed Implementation

[0021] Reference Figure 1 , Figure 2 This invention provides a method for planning a single-aircraft grid-shaped search route in a small area. Considering kinematics and plane geometry principles, it establishes a single-aircraft grid-shaped search route model in a two-dimensional space. Specifically, it includes the following steps:

[0022] (1) Determine the search area: Considering the target's mobility, the search range is normalized into a rectangular search area ABCD with a length of L1 and a width of L2. The position coordinates of the four corners can be known.

[0023] (2) Given that the visibility distance on the day is d, in order to ensure that no target is missed in the search, the horizons of each side of the flight path need to have a certain overlap. The overlap rate is usually 25%. Therefore, the interval of each side of the search grid is determined to be 1.75 times the visibility distance (i.e. 7d / 4). Then, the number of search sides required to search the entire area is N = L1 / (1.75d).

[0024] (3) Determine the entry point A for the helicopter to search the area: If the helicopter is planned to search from left to right, then point E, which is 1.75d / 2 east of point A, will be the entry point for the search.

[0025] (4) Determine the location of the first turning point F: The first turning point F is located at a distance of L2-r due south of point E.

[0026] The specific calculation process for point F is as follows:

[0027] (301) Given that the ground speed of the helicopter is W, the wind speed is U, the wind angle is f, and the yaw angle is p, then the vacuum speed is TAS = (W - Ucosf) / cosp;

[0028] (302) Given that the helicopter's turning angle is β and the local gravitational acceleration is g (usually 9.8 m / (s×s)), the helicopter's aerial turning radius r = TAS×TAS / (g×tanβ);

[0029] (303) The coordinates of point F are obtained from the coordinates of point E. The first turning point, point F, is located at a distance of L2-r from due south of point E.

[0030] (5) Perform a turning flight at turning point F. There are two ways to perform a turning flight: The first way is to make a 90° turn at the turning point to the first leveling point G, and then fly horizontally along the length direction for 1.75d-2r at leveling point G to the next turning point H, and then make a 90° turn to the next leveling point I; The second way is to make a turn at the turning point with a turning diameter of 1.75 times the visibility, and make a turning flight with a turning slope of 180° to leveling point I.

[0031] like Figure 1 As shown, if a 90° turn is taken, then:

[0032] The method for determining the coordinates G of the first leveling point of my machine is as follows: at a distance of 45° southeast of point F. That point is G;

[0033] Determine the level flight distance on side BC: Starting from the first leveling point G, the level flight distance in the due east direction is 1.75d-2r, and the coordinates of the second turning point H are obtained;

[0034] Determine the location of the second leveling point I: 45° northeast of turning point H. The location is the second leveling point I, and its coordinates can be obtained.

[0035] Determine the location of the next turning point J: The location of J is a distance of L2-2r from due north of the leveling point I, and its coordinates can be obtained;

[0036] The subsequent turning points, leveling points, and level flight distances are obtained sequentially until N edges are searched. After exiting the rectangular search area, the coordinates of all key waypoints on the search flight path are obtained, and the search route planning is completed.

[0037] like Figure 2 As shown, if a 180° turn is taken, then:

[0038] The turning radius is 1.75d / 2, and the first leveling point I is located 1.75d away from point F in the due east direction.

[0039] Determine the location of the next turning point J: The location of J is a distance of L2-2r from due north of the leveling point I, and its coordinates can be obtained;

[0040] The subsequent turning points, leveling points, and level flight distances are obtained sequentially until N edges are searched. After exiting the rectangular search area, the coordinates of all key waypoints on the search flight path are obtained, and the search route planning is completed.

[0041] Complete the single-aircraft sector search route planning for small area targets.

Claims

1. A method for planning flight paths in a small-area single-machine grid-like search, characterized in that, Includes the following steps: (1) Estimate the maximum length and maximum width of the search task area based on the target activity range to obtain a rectangular search area with a length of L1 and a width of L2; (2) Based on the visibility d, the interval between each side of the search grid is determined to be 1.75 times the visibility distance. Then, the number of search sides required to search the entire area is N = L1 / (1.75d). (3) Determine the search area entry point of the search helicopter based on the width of the rectangular search area and the current visibility d. That is, take the position 1.75d / 2 away from one end boundary on the long side of the rectangular search area as the entry point for the helicopter to fly into the search area, and then fly straight towards the turning point along the width direction. (4) Turning flight at the turning point. The turning flight methods are as follows: The first method is to make a 90° turn at the turning point to the first leveling point, and then fly horizontally along the length direction for 1.75d-2r distance to the next turning point, and then make a 90° turn to the next leveling point, where r is the helicopter's aerial turning radius; The second method is to make a turn at the turning point with a turning diameter of 1.75 times the visibility, and make a turning flight with a turning slope of 180° to the next leveling point. (5) Fly along the width direction to the next turning point from the next flat point, return to step ④, and exit the rectangular search area after completing the N edge search. Complete the planning of single-aircraft grid-shaped search routes in a small area.

2. The method for planning a small-area single-aircraft grid-shaped search route according to claim 1, characterized in that, When entering and exiting the rectangular search area, the horizontal flight distance of the search edge in the width direction of the rectangular search area is L2-r, and the horizontal flight distance of the other search edges is L2-2r; Where r = TAS × TAS / (g × tanβ), TAS = (W - Ucosf) / cosp; In the formula, W is the helicopter's ground speed, U is the wind speed, f is the wind angle, p is the yaw angle, β is the helicopter's turning angle, and g is the local gravitational acceleration.

3. The method for planning a small-area single-aircraft grid-shaped search route according to claim 2, characterized in that, In step (4), if a 90° turn is adopted, then at the distance from the turning point The first leveling point is located at the intersection of the long side and the long side along the length direction; if a 180° turn is adopted, the leveling point is located 1.75d away from the turn point along the length direction.

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