RU2601494C1 - Method of aircraft coordinates determining based on using two directional angles and one of elevation angles - Google Patents

Abstract

FIELD: aircraft engineering.

SUBSTANCE: invention relates to methods of aircraft coordinates determining. For determining of aircraft coordinates information is received and generated in spatially spaced apart receivers, information is simultaneously recorded based on aircraft two directional angles and elevation angle, processed in computer in certain manner, determining aircraft coordinates in geodesic coordinate system.

EFFECT: reduced time of information processing when determining aircraft spatial coordinates.

1 cl, 2 dwg

Description

The invention relates to the field of detection and determination of coordinates of aircraft and can be used in military equipment.

There are various methods for determining the coordinates of objects using methods for transmitting and receiving radio signals from ground-level radio beacons (RF patent No. 2436232) and a method of triangulating targets (RF patent No. 2423720) [1, 2]. The disadvantages of these methods is the complexity of processing the information received from the points of detection of objects, the use of only the active radar range of electromagnetic waves.

A method for automatically determining the coordinates of unmanned aerial vehicles (RF patent No. 2523446 - prototype) [3] consists in the use of all-round cameras, a space-oriented video monitor, a computer and a laser rangefinder to illuminate the aircraft, characterized in that the all-round cameras are placed symmetrically and are directed in different directions, so as to conduct 360 ° observation in the optical range of electromagnetic waves day and night, and the appearance of the aircraft is automatically detected as a hindrance, knowing the video sequence on the frame relative to the previous one, and the obtained data are processed on a computer, where the angular values of the aircraft’s location are generated in the horizontal height relative to the center of the angle measuring device, which, using rotary mechanisms, directs the laser rangefinder to the aircraft to measure the distance to it, then the measured distance from the aircraft enters the device for processing and displaying information (computer), where there is an automated determination of the spatial coordinates X _{UAV, UAV} Y, Z _UAV aircraft.

The main disadvantages are the unmasking component of this method associated with the use of laser radiation, which reduces the efficiency of using the above method for detecting and determining the spatial coordinates of aircraft in a hidden mode of operation, as well as large errors of the rotary mechanisms in the process of aiming the laser rangefinder and processing the received information.

As a common drawback of these methods for determining the coordinates of aircraft is the incomplete use of measurement data and, as a consequence, non-maximum accuracy.

The challenge facing the present invention is to increase the accuracy of determining the coordinates of aircraft and reduce the time it takes to process the received information in passive and active modes of operation.

The problem is solved as follows.

At present, the direction-finding method for determining the coordinates of objects is widespread in the practice of optical and radar external trajectory measurements. It is based on measuring the angular coordinates of the object in the horizontal (azimuth or directional angle) and vertical (elevation angle) planes (Fig. 1). In this case, two measurement points (PI) are enough to uniquely determine the spatial coordinates of the aircraft.

As a result of measurements from two PIs, the values of the directional angles and elevation angles (α ₁ ; ε ₁ ) and (α ₂ ; ε ₂ ) are determined, according to which the coordinates of the object are recalculated in a rectangular geodetic coordinate system.

where B is the base, i.e. distance between FE;

And _X is the azimuth (directional angle) from one IP to another.

Further necessarily synchronous measurements of these angles allow us to calculate the coordinates of the object related to subsequent time instants.

But even in this case, it is noteworthy that the totality of the measured parameters, which are four numbers, contains a certain redundancy of data, since the minimum information necessary to determine the position of the center of mass of an object (aircraft) in any SC should contain three independent measurements. This is also evidenced by the fact that the number of degrees of freedom of a material point is three. This fact is confirmed by the form of the above dependencies, which as arguments contain only three quantities (A ₁ , A ₂ , ε ₁ ). Usually the fourth parameter is either completely discarded, or at best used for control. However, in either case, information is lost.

It is known from theory that a pair of numbers (α; ε) geometrically uniquely defines a line in space. With two measuring points of such lines, two can be built. These lines intersect at the point where the object is located at the time of notching. However, if there are measurement errors, the direct SP _i -O in the general case will not intersect at one point, but will be crossed. The true position of the object will be determined by a certain region of space, which will be the greater, the lower the accuracy of measurement of quantities (A _i , ε _i ). Improving the reliability of the results can be achieved by increasing the number of PIs, but in this case it is not possible to use the classical dependences (1). Thus, it is necessary to look for other ways of processing the results of VTI.

The minimum information necessary to determine the position of the center of mass of an object (aircraft) in any SC should contain three independent measurements.

In the future, the problem is reduced to recalculating the three initial values of the spherical SC into the three of the desired values of the rectangular SC. The number of possible combinations of triples of numbers from four is equal to C ³ ₄ = 4. Two fundamentally different geometric approaches to solving the problem of determining the object are possible here.

From the four measured values, we choose (α ₁ ; ε ₁ ; α ₂ ) or (α ₁ ; α ₂ ; ε ₂ ). Of these, two quantities (α ₁ ; ε ₁ ) determine the line passing through AND ₁ in the direction of the object. The geometrical location of the points for which α ₂ = cosnt is the vertical plane passing through PI ₂ (Fig. 2). Thus, the position of the object will be determined by the point of intersection of the line and the plane.

In the general case, a plane and a straight line in space can be located in one of the following images.

1. The line belongs to the plane. In this case, these objects will have an infinite number of common points.

2. The line is parallel to the plane, but does not belong to it. In this case, these objects do not have common points.

3. The line crosses the plane. In this case, the line and the plane have one common point.

будет иметь координаты (0; 1; 0). Вектора $$\overrightarrow{A}\text{ и }\overrightarrow{B}$$

принадлежат вертикальной плоскости (1), тогда нормаль этой плоскостиWe determine the coordinates of the aircraft in the HSC X _g h _g Y _g using the minimum necessary information for this, i.e. three independent quantities, for example (α ₁ ; α ₂ ; ε ₂ ). We compose the equation of the vertical plane (1) passing through the IP ₁ in the direction of α ₁ . To this end, we consider a unit horizontal vector A (figure 2). The projections of this vector on the HSC axis will be equal to (cos α ₁ ; 0; sinα ₁ ). Unit vertical vector $$\overrightarrow{B}$$

will have coordinates (0; 1; 0). Vectors $$\overrightarrow{A}\text{and}\overrightarrow{B}$$

belong to the vertical plane (1), then the normal of this plane

n = A × B = (- sin α ₁ ; 0; cosα ₁ ).

A vector with a beginning at point IP ₁ and with an end at an arbitrary point M (x; h; y) belonging to the plane (1) will have coordinates (xx ₁ ; hh ₁ ; yy ₁ ). Here the index "G" is omitted. It is orthogonal to the normal of the plane n, so their scalar product is zero, i.e.

-sinα ₁ (xx ₁ ) +0 (hh ₁ ) + cosα ₁ (yy ₁ ) = - х · sinα ₁ + y · cosα ₁ +

+ (x ₁ sinα ₁ -y ₁ cosα ₁ ) = 0.

Because the canonical equation of the plane has the form:

Ax + By + Cz + D = 0,

and in terms of the problem being solved

Ax + Bh + Cy + D = 0,

then

A = -sinα-1; B = 0; C = cosα ₁ ; D = x ₁ sinα ₁ -y ₁ cosα ₁ .

We define the equation of a straight line passing through FE ₂ in the direction to the aircraft and set by the values of α ₂ and ε ₂ . To do this, we consider the unit vector C. Its projections on the HSC axis are equal (cosε ₂ cosα ₂ ; sinε ₂ ; cosε ₂ sinα ₂ ). Thus, the equation of the desired line is written in the form:

Because the canonical equation of the line has the form:

(x-a) / m = (y-b) / n = (z-c) / p,

where (a; b; c) - coordinates of a point belonging to a line;

(m; n; p) are the coordinates of a vector parallel to the line, then under the conditions of the problem being solved:

(x-a) / m = (h-b) / n = (y-c) / p = k,

where a = x ₂ ; b is h ₂ ; c = y ₂ ; m = cosε ₂ cosα ₂ ; n = sinε ₂ ; p = cosε ₂ sinα ₂ .

The point of suppression of the line and the plane is determined by the following algorithm.

1. The parameter k is determined - the coefficient of proportionality in the equation of a straight line in space

k = - (Aa + Bb + Cc + D) / (Am + Bn + Cp).

2. The coordinates of the point of intersection of the line and the plane are determined

x = a + mk; y = b + nk; z = c + pk.

In the conditions of the problem being solved

k = - (- x ₂ sinα ₁ + y ₂ cosα ₁ + x ₁ sinα ₁ -y ₁ cosα ₁ ) /

(-cosε ₂ cosα ₂ sinα ₁ + cosε ₂ sinα ₂ cosα ₁ ) =

= [(x ₂ -x ₁ ) sinα ₁ + (y ₁ -y ₂ ) cosα ₁ ] / [cosε ₂ sin (α ₂ -α ₁ )].

Finally

k = [(x ₂ -x ₁ ) sinα ₁ - (y ₂ -y ₁ ) cosα ₁ ] / [cosε ₂ sin (α ₂ -α ₁ )],

x _LA = x ₂ + k · cosε ₂ cosα ₂ ; h _LA = h ₂ + k · sinε ₂ ; for _LA = y ₂ + k cosε ₂ sinα ₂ ,

where (x _G ; h _G ; z _G ) - the coordinates of the aircraft in the HSC.

Reference information: sin (α-β) = sinα · cosβ-sinβ · cosα.

For another similar combination of measured parameters (α ₁ ; ε ₁ ; α ₂ ), the solution geometry does not change, i.e. the intersection of the plane and the straight line is sought.

Thus, the method of determining the spatial coordinates of aircraft based on the use of two directional angles and elevation angle allows you to determine the point at the intersection of the line and the plane, which reduces the processing time of the received information from sensors operating in the optical and radar ranges of electromagnetic waves.

Information sources

1. Panov V.P., Prikhodko V.V. A method for transmitting and receiving radio signals of terrestrial beacons. - FIPS. Patent for invention No. 2436232, 12/10/2011

2. Bezyaev B.C. A way to triangulate goals. - FIPS. Patent for invention №2423720, July 10, 2011

3. Shishkov S.V. A method for automatically determining the coordinates of unmanned aerial vehicles. - FIPS. Patent for invention No. 2523446, 05/26/2014

Claims (1)

A method for determining the coordinates of aircraft based on the use of two directional angles and one elevation angle, which consists in receiving and generating information in spatially separated receivers while simultaneously recording information about the aircraft and analyzing it on a computer, characterized in that the information received from the two separated receivers is processed based on the use of information from two directional angles and the elevation angle of the aircraft, the proportionality coefficient is determined in the equation straight line in space k = [(x ₂ -x ₁ ) sin α ₁ - (y ₂ -y ₁ ) cos α ₁ ] / [cos ε ₂ sin (α ₂ -α ₁ )], and determine the coordinates of the aircraft in the geodesic coordinate system x _LA = x ₂ + k · cos ε ₂ cos α ₂ ; h _LA = h ₂ + k · sin ε ₂ ; for _LA = y ₂ + k · cos ε ₂ sin α ₂ , which reduces the processing time of the received information from sensors operating in active and passive modes in the optical and radar ranges of electromagnetic waves.

Images