RU2388059C1 - Method of evaluating proximity of path of aircraft to earth's surface - Google Patents

Abstract

FIELD: physics; control. ^ SUBSTANCE: invention relates to air traffic control. According to the proposed method, position of an aircraft is determined using a navigation system. Parametres of the current dynamic status are determined. A forecast path is calculated and proximity of the path to topographical features is evaluated. The evaluation of the proximity of the path to the Earth's surface is done by constructing a set of spheres whose centres are on the path, and whose radii are equal to minimum distance to the topographical features and artificial obstacles to the corresponding centres. The spheres are constructed such that, the centre of each next sphere lies on the point of intersection of the approximated forecast path of the aircraft with the surface of the previous sphere. ^ EFFECT: invention increases flight safety of aircraft through dynamic evaluation of proximity of the path of the aircraft to the Earth's surface. ^ 1 dwg

Description

The invention relates to the field of flight safety and, in particular, to methods for determining the proximity of the trajectories of aircraft (LA) to the elements of the earth's surface. The invention is intended for use on any type of aircraft, including those having high maneuverability.

State of the art

There are and are widely used methods designed both for accurate determination and for assessing the proximity of aircraft trajectories to terrain features. They are based on determining the position of the aircraft using the navigation system, determining the parameters of the current dynamic state, calculating the predicted trajectory, forming a zone of a certain shape that provides the necessary distance to the elements of the earth's surface, comparing it with the terrain and, as a result, varying in degree of accuracy assessment of the proximity of the trajectory to the terrain based on a comparison of the sizes of such a zone and the relief elements that fall into it [RU 7000106, US 60097895, US 7321813, US 70185652, US 70050101].

In these methods, the assessment of the proximity of the trajectory to the earth's surface is done by analyzing the presence of terrain features in the spatial region at the aircraft heading [see, for example, RU 7000106, US 60097895, US 7321813, US 70185652, US 70050101].

The disadvantage of such existing methods is due to the limited ability to assess the proximity of the earth's surface to the trajectory for any predicted point in time, as well as their low applicability to aircraft with high maneuverability. These shortcomings are found due to the fact that determining the proximity of the earth’s surface is based on an analysis of the penetration of relief elements into a spatial zone of a fixed shape, which in various works is called a “security corridor”, “security profile” or “security zone”, and which degree takes into account the possible development of the flight situation in time. Thus, the terrain element located in close proximity to the current position of the aircraft or its predicted trajectory, but not falling into the “safety zone”, due to the peculiarities of its construction, will not be taken into account, which can lead to a collision. Meanwhile, in order to avoid a collision, in many cases, it is necessary to have information about the proximity of the earth for all points of the predicted trajectory in all directions in order to be able to pre-adjust the trajectory based on a constant assessment of its proximity to the earth's surface, which is of particular importance for highly maneuverable aircraft.

As the closest analogue of the proposed method, the selected method for assessing the proximity of the aircraft trajectory to the terrain described in US60097895. It should be noted that this method is only a partial analogue of the claimed.

In the method selected as the closest analogue, the most common and characteristic actions are performed, which serve to assess the proximity of the aircraft trajectory to the earth's surface, namely, determine the location of the aircraft using the navigation system, determine the parameters of the current dynamic state, form the so-called "profile security ”, check the absence of terrain features and artificial obstacles in it. In case of detection of relief elements, an estimate is obtained of the proximity of the path section for which a “safety profile” containing the relief element to the earth's surface is built.

This method provides the ability to determine the proximity of the earth's surface only in a fairly limited area near the immediate location of the aircraft. The determination of the proximity of the terrain is carried out without taking into account the forecast of the development of the situation for a certain time ahead and only if it falls into the “safety profile”, at other times when the “safety profile” is clear, the pilot does not have any information about the proximity of the terrain. This circumstance makes it impossible for the pilot to make early decisions regarding further actions based on the current and predicted altitude.

Thus, the determination of the proximity of a dangerous terrain is not fully implemented.

Disclosure of invention

The basis of the claimed invention is the task of improving flight safety, which is achieved by assessing the proximity of the aircraft trajectory to the earth's surface. An assessment of the proximity of the trajectory to the terrain is used in flight safety systems, including active ones, to assist the crew in making decisions regarding aircraft control modes and, as a result, to prevent collisions with the earth's surface.

In accordance with this, to implement the method, it is necessary to have data on the passage in space of the trajectory, the proximity of which to the elements of the terrain is estimated. In the case of determining the proximity of the earth's surface to the predicted trajectory, the initial conditions for its calculation are set by the current dynamic parameters of the aircraft.

The essence of the proposed method is based on an estimate of the minimum distance to terrain features for each of the points belonging to the predicted trajectory. In this case, the determination of the minimum distance is made in all directions and is based on the principle of constructing spheres free from terrain features and artificial obstacles, centered at the point of the predicted trajectory, for which the proximity of the earth's surface is estimated. The construction of the spheres is carried out in such a way that the center of each subsequent sphere is located at the intersection of the approximate predicted trajectory of the aircraft with the surface of the previous sphere.

Thus, for a section of the trajectory located inside the zone formed by the spheres, an estimated distance to the terrain is formed, which is determined by the radius of the corresponding sphere. In the process of combining the spheres constructed in this way, the proximity of the aircraft trajectory to the earth's surface is estimated for any predicted point in time.

Brief Description of the Drawings

The drawing shows a set of spheres, the radius of each of which forms the minimum distance from the center point of the sphere belonging to the aircraft trajectory to the elements of the earth's surface. A trajectory point inside the sphere is considered as far from the terrain as the shortest distance from this point to the surface of the sphere, provided that this surface is not part of the subsequent or previous sphere.

The implementation of the invention

The inventive method is implemented by the following sequence of actions.

ω_у и др.).Using the navigation system, the location and current parameters of the dynamic state of the aircraft 1 are determined (ground speed - W _p , vertical speed - W _y , track angle - PU, turn speed -

ω _y , etc.).

The next step is to calculate the predicted trajectory 2, for a certain time ahead. The predicted trajectory is calculated in a separate functional block by solving the system of differential equations of motion for the aircraft.

Further implementation of the method is carried out using the on-board database (BDB) functional block.

The BBB contains a digital terrain model, which is a set of elevation elevation elevation 3 values that are tied to the corners of the grid and are a digital expression of the elevation characteristics of the terrain on a topographic map. Additionally, the BDB contains information on man-made obstacles of anthropogenic origin, including information on aerodromes (coordinates and excess of control points of aerodromes, coordinates and excess of thresholds of the runway (runway), magnetic / true runway track angles). The on-board database can be implemented in a separate functional unit.

Based on the current coordinates of the aircraft in the form of X, Y, Z (where X is the current geographic latitude, Y is the current geographic longitude, Z is the aircraft altitude above the geoid at the current moment) obtained using the navigation system, and the actual heading block BDB transmitted predicted trajectory specified, for example, in the form of an array of points approximating a curve in space, or in any other way.

At the output of the BBB block, after processing the received information, an array of radii 5 is returned, equal to the minimum distance 4 to the terrain and artificial obstacles for the centers of the corresponding spheres, and the true heights of the aircraft in the same centers.

The data received from the BBB block are combined together, as a result of which the spheres 6, in accordance with the calculated radii, form an estimate of the proximity of the aircraft trajectory to the earth's surface.

Claims (2)

1. A method for assessing the proximity of the trajectories of aircraft (LA) to the earth's surface, according to which the location of the aircraft is determined using the navigation system, the parameters of the current dynamic state are determined, using the obtained parameters and the actual course of the aircraft, the predicted aircraft trajectory is calculated, characterized in that they build a set terrain-free spheres with centers located on the predicted trajectory and radii equal to the minimum distance from the corresponding centers to lementov terrain and man-made obstacles, and the proximity portion of the trajectory located within the zone formed by spheres, is judged by the respective radii of the spheres. 2. The method according to claim 1, characterized in that the construction of the spheres is carried out in such a way that the center of each subsequent sphere is at the intersection of the approximated predicted trajectory of the aircraft with the surface of the previous sphere.