RU2498342C1 - Method of intercepting aerial targets with aircraft - Google Patents

Abstract

FIELD: physics.SUBSTANCE: method involves measuring polar coordinates of a target and an airplane in the horizontal plane; the control point estimating polar and rectangular coordinates thereof, the heading of the target and velocity of the airplane and the target; introducing an auxiliary point A lying on the velocity vector of the airplane at a distance D; determining the required heading ?of the airplane, the value of which is sent from the control point to the airplane, where its current heading ?is measured and the control parameter ??=?-?is determined; controlling the trajectory of the airplane, wherein the control point estimates the heading ?of the airplane and the point A is selected by setting its rectangular coordinates; calculating the target viewing angle relative point A; determining bearing angles which are angles between velocity vectors of point A and the target, respectively, and the "point A - target" viewing line; determining the value of the required heading ?of the airplane based on the condition of equality of velocity projections of point A and the target on the perpendicular to the "point A - target" viewing line; the pilot assesses the possibility of intercepting aerial targets with the airplane using a visual image on a display screen of the predicted position of the target (point of interception), for which the computer system of the control points finds rectangular coordinates of the point of interception using corresponding formulae.EFFECT: high situational awareness of the pilot on the end results of navigation and simple corresponding computations.8 dwg

Description

The present invention relates to methods for aiming aircraft (LA) at air targets, in particular, to methods for aiming aircraft used in command radio control systems.

In modern conditions, much attention is paid to multi-functional aircraft control systems. When hovering over air targets, the first stage is the long-range guidance (NAM) [1, p. 218, 219].

A significant role at the stage of NAM is played by the process of controlling the aircraft on the course. Guidance methods for the course predetermine the formation of the required values ψ _{T of the} course, determining the desired guidance path in the horizontal plane. In this case, the mismatch parameters that determine the algorithms of the trajectory control of the aircraft in the manual control mode are formed according to the rule:

in which ψ _c is the current value of the course.

Aircraft guidance methods implemented by the long-range guidance system (SDS) should provide: minimum guidance time, maximum range, minimum instantaneous overload of the aircraft, minimum energy consumption of control signals, practical feasibility, invariance of the control system to the conditions of use, interfacing with the methods used on subsequent stages of the combat mission. In this case, a good combination of guidance methods for SDS and the homing system used in the future, which ensures an organic (without significant transient processes) transition of the aircraft radio control system from the long-range to the short-range guidance, is of greatest importance.

Among the known methods of guidance on the course in SDS by airplanes, maneuver method, interception method and direct method are most widely used [1, pp. 228-231].

With the direct method, also called the chase method, it is required to combine the longitudinal axis of the aircraft with the direction to the target all the time. The disadvantages of the method include: the difficulty of piloting an airplane due to the constant change in heading and roll, the increased flight time before meeting.

The maneuver method ensures that the aircraft enters the target detection area of the onboard radar, optoelectronic station or telescopic sight at a given angle ψ _to at a given distance to the target. The disadvantages of the method are: the long time it takes to get the aircraft to the capture line, high fuel consumption, which reduces the time for conducting air combat, restrictions on the intercept angles from the front hemisphere, due to the need to take the plane to the rear hemisphere, the complexity of calculating the trajectory and its implementation.

The interception method, which is taken as a prototype, is a variation of the parallel approach method [1, pp. 230-231]. Its peculiarity is that according to the method of parallel approach, it is not the aircraft itself that is induced, but some auxiliary (fictitious) point A located along the velocity vector V _c at a distance D _c from the induced aircraft (Fig. 1). As the range D _s can be used the detection range of the airborne radar. This means that in the process of long-range guidance, the direct AO _c moves parallel to itself. Such a technique ensures that the aircraft is located at the point O _c at the boundary D _z at the moment when point A “meets” at the anticipated meeting point O _ut with the target.

In the drawing, the points O _c , O _pu and O _c correspond to the position of the aircraft, the control point (guidance) and the target; V _c and V _c - the speed of the induced aircraft and the target; x _c , z _c and x _s , z _c - the current rectangular coordinates of the target and the plane. Estimates of the coordinates x _c , z _c and x _c , z _c are formed on the basis of the measured in the radar associated with the control point, the ranges D _c , D _c and azimuths φ _c , φ _{from the} target and aircraft (Fig. 2) using the rules:

Using the coordinates of the target x _c , z _c and the plane x _s , z _c and taking into account that the anticipated range D _y is equal to the sum of D _c and the distance O _c O _c flown by the plane during the guidance time t _n (Fig. 1), we obtain the system of equations [1, p. 230]: -

with three unknowns ψ _Т , t _н and Д _у . Upon receipt of (3), it was assumed that the target and the plane move uniformly and rectilinearly with velocities V _c and V _c and course angles ψ _c and ψ _T, respectively. Solving this system under the condition that the rectangular coordinates are determined according to the rules (1), (2), ψ _Т , t _н and Д _у are calculated.

From (3) it follows that to implement the method of interception, it is necessary to evaluate the rectangular coordinates of the target and the aircraft, the speed of the aircraft and the target, and the target angle ψ _c . The latter requires a sufficiently long tracking of the target.

A simple solution to the system (3) is obtained provided that the aircraft is hovering in oncoming or catch-up courses. In this situation, taking into account (2) from (3) get [1, p. 231]:

Where

From (4) and (5) it follows that in order to implement the interception method, it is necessary to evaluate the ranges and azimuths of the target and the aircraft, as well as the speed V _c and V _c and the target angle ψ _c .

The main advantages of the interception method are:

high cost-effectiveness of guidance, due to guidance in a pre-determined point almost along a straight line path;

providing a predetermined line of interception at any angle of guidance.

It should also be noted that this method provides a good pairing of a rectilinear section of the trajectory of the aircraft with the trajectory of the rocket [2, p. 388]. The disadvantage of this method of interception is the low level of situational awareness of the pilot of the guided aircraft about the expected results of the guidance process at a given air target, which makes it difficult for them to assess the tactical situation. In addition, to implement the prototype method, it is necessary to solve a system of nonlinear equations (3), which requires the implementation of a complex computational procedure, which is organized in the information-computer system of a control point (PU). In the linearization of equations (3), the required aircraft heading is calculated with large errors at target angles other than zero.

The purpose of the invention is to increase the situational awareness of the pilot about the possible final guidance results and to simplify the computational procedure for determining the desired course and guidance time.

The technical result consists in increasing the information content of the long-range guidance system, based on the introduction of data generation procedures characterizing the spatial position of the intercept point and the time of aiming at an air target, and visual display of these data on the guided aircraft, in reducing the computational cost in the information and computing system of the missile launcher. In addition, it provides an extension of the scope of the interception method when aiming not only at air targets, but also at other types of targets, for example, surface targets.

To implement the claimed technical result, the polar coordinates of the target and the plane are measured in a horizontal plane, the polar and rectangular coordinates of the target and the plane, the target course and the speed of the plane and the target are measured at the control point, the auxiliary point A located on the line along the speed vector V _{c of the} plane a distance _h is determined desired rate ψ _T of the aircraft, which value is transmitted to the UE on a plane where its measured current rate ψ _to determine control parameters and Δψ = _ψ ψ _T -ψ _c, sound control is performed Lenie trajectory of movement of the plane. In contrast to the prototype, on the control panel, the course ψ _{ñ of the} aircraft is estimated and the rectangular coordinates of the fictitious point A are set

z _a = z _c + D _s sinψ _T

x _a = x _c + D _s cosψ _T

where x _a , z _a , x _c , z _c are the estimates of the rectangular coordinates of point A and the plane, the angle of sight of the target relative to point A is calculated, the angles of the bearing φ _a and φ _c , which are the angles between the velocity vectors V _c and V _{c of the} point, are determined A and the target, respectively, and the line of sight “point A - target”, determine the value of the required course ψ _T of the aircraft motion from the condition that the projections of the velocities of the speeds of point A and the target perpendicular to the line of sight “point A - target” are equal, the pilot estimates the expected results of solving the interception problem airborne target using a visual display on the screen of the indicator of the predicted position of the target (interception point) at the end of the long-range guidance stage and the guidance time, for which the rectangular coordinates of the interception point are found in the control computer system using the formulas:

x _yt = x _a + V _c t _н cosψ _T , z _ut = z _a + V _c t _н sinψ _T ,

or

x _yt = x _c + V _c t _n cosψ _c , z _ut = z _c + V _c t _n sinψ _c ,

and guidance time

,

,

or

,

,

where x _c , z _c are the estimates of the rectangular coordinates of the target, ψ _c is the target's course, this data is output and transmitted via the command radio control line to the display system on the plane.

List of figures:

Figure 1 and Figure 2, the Interception method of the prototype [1, p. 230-231].

Figure 3. The geometry of the aircraft pointing at an air target using the proposed method.

Figure 4. Generalized block diagram of a radio control system.

Figure 5. The results of the simulation of interception for the prototype method.

6. Interception simulation results for the prototype method with a linearized algorithm.

7. The results of the simulation of interception for the prototype method with a linearized algorithm with new source data for the fighter.

Fig. 8. Interception simulation results for the modified method.

To obtain a technical result by the proposed method, we use the well-known equations for the parallel approach method, in which the line AO _c connecting point A and target O _c must move parallel to itself.

The geometry of the relative position of all objects involved in the process of pointing the aircraft at an air target is shown in Fig. 3.

In the triangle AO _ut O _{c, the} angles of the bearing φ _a and φ _c are the angles between the velocity vectors V _c and V _c, respectively, and the line of sight of the AO _c . The viewing angle ε _{c of the} target from point A is formed by the beams AX _os and AO _c . Accordingly, ε _Ца is the angle of sight of point A relative to the target О _Ц.

From figure 3 it is seen that the rectangular coordinates of point A are equal to:

The viewing angles are associated with the rectangular coordinates of the corresponding points A, O _c and O _{with the} following ratios (figure 3):

In turn, the angles of the bearing φ _a and φ _{c are} determined by the following equalities:

As you know, with the method of parallel approach of point A and the target of projection of the speeds of point A and the target, perpendicular to the line of sight of AO _c , should be equal to each other:

When substituting in (9) the values of φ _a and φ _c from (8) we obtain:

In (10), ψ _Т is the required aircraft course with the exact implementation of the modified interception method when the ψ course _{from the} aircraft coincides with its required value. It follows that the required course of the aircraft:

In the process of guidance, the actual ψ _c and the required ψ _t courses may not coincide. Therefore, when determining the rectangular coordinates of point A in expressions (6-7), instead of ψ _T, it is necessary to substitute ψ _s . It follows that the modified method of intercepting requires an additional assessment of the course ψ _{from the} aircraft using the results of primary measurements of the polar coordinates of the aircraft at the control station.

If the interception of an air target is carried out at small angles φ _a and φ _c , i.e. on the oncoming or catch-up courses, then the formula (11) is simplified:

where a = V _c / V _c - coefficient characterizing the ratio of the speeds of the target and the plane.

To find the guidance time t _n, you can use the relations that relate the rectangular coordinates of the interception point, the coordinates of point A, the rectangular coordinates of the target, the desired airplane course, target course and guidance time (Fig. 3):

,

,

,

,

Equating the coordinates of the intercept point of the same name from (13) and (14), the guidance time is found:

or

To calculate the guidance time t _H, one can use formula (15) or (16).

Necessary for the implementation of the method of intercepting estimates of the coordinates and motion parameters of the target and the aircraft are formed using well-known estimation (filtering) algorithms given in the scientific and technical literature, for example, in [3, p. 183-217].

The pilot can evaluate the predicted results of solving the problem of intercepting an air target by an aircraft by using a visual display on the screen of the indicator of the spatial position of the calculated interception point and indicating the guidance time. For this, it is necessary to perform calculations according to formulas (13) - (16) and to carry out the procedure for deriving and displaying calculation results.

Implementation of the proposed guidance method is provided by a radio control system, an example of which is shown in FIG. four.

The coordinates of the target and the aircraft are measured at the radar station (RLP) 1 and through the data transmission system (SPD) 2 are transmitted to the control room 12, where they enter the computer system (AC) 3 and the information display device (UOI) 4. At the control point, operator 5 responsible for the overall organization of the process of pointing the aircraft to the chosen target. When implementing a modified guidance method, the operator controls the guidance process. To ensure successful interception of the target, the pilot needs to know the possible consequences of decisions made at the launcher and the requirements for piloting the aircraft. With regard to solving a specific interception task, he should have an idea of the possible spatial position of the interception point at the time of the end of the stage of the attack and the duration of the stage of the attack. For this, in the computing system 3, the calculations of its rectangular coordinates and guidance time are performed according to expressions (13) - (16).

In addition, the aircraft 3 evaluates the coordinates and motion parameters of the target and the aircraft, as well as determines the desired course of the aircraft. Using the command radio control line (KRU) 13, the value of the required course, the coordinates of the interception point and the guidance time are transmitted to the on-board computer system (BVS) 8 of the guided aircraft 14. The course sensor (DK) 9 measures the current course of the aircraft and provides its value in the BVS 8, where a control parameter is generated, which is displayed on the indicator screen (EI) 10. Pilot 11 evaluates the tactical situation using EI 10, determines the value of the control parameter, and pilotes the plane so as to maintain the control parameter equal to zero.

To assess the effectiveness of the proposed method, a simulation of the process of intercepting a target by an induced aircraft with PU was performed. For this, a simulation model of the interception process was developed.

In the simulation, it was assumed that the air target moves uniformly and rectilinearly.

For an induced aircraft, the derivatives of its rectangular coordinates for known values of speed V _c and course ψ _{s are} calculated by the formulas:

,

.

,

.

In this expression, ψ _c is the aircraft heading associated with its lateral acceleration by the ratio [1, p.176]:

.

.

In the simplest case, lateral acceleration is determined by the formula [1, p. 190]:

,

,

where k ₁ is the transmission coefficient of self-propelled guns and aircraft, as a control object.

Since the aircraft is aimed at the target by the claimed method, ψ _T is determined by expression (14). The control parameter is generated according to the rule

Δ _ψ = ψ _T -ψ _s ,

where ψ _c is the simulated course of the aircraft.

The coordinates of point A were calculated based on relations (6).

Models of forming viewing angles and bearings for the developed method of interception are described by relations (7) and (8).

The models for estimating the coordinates and motion parameters of the target and the aircraft characterize the algorithms for constructing their trajectories in the information and computing system of the control system, which are based on filtering the results of indirect measurements of the rectangular coordinates of the target and the aircraft, respectively.

Aerial target interception simulation was carried out in Matlab 7.3.0 for three options for calculating a given fighter heading:

1) a nonlinear system of equations (3) was solved;

2) the target course of the fighter and the guidance time were found using the linearized equations (4) and (5);

3) the required course was calculated using the developed method, based on equation (11), and the guidance time - in accordance with one of the equivalent equations (15), (16).

The calculation of the required course of the fighter was carried out with a resolution of five seconds. At the same time intervals, the current coordinates of the air target and the fighter were determined. Simulation of all three options was carried out with the following initial data: a given range of D _z = 30 km, the initial course of the fighter ψ _c = 270 ° and the initial course of the target ψ _c = 90 ° and the angle of sight of the target relative to the fighter ε _sc = -45 °.

The initial course of the fighter ψ _о was set in the opposite direction to the target ψ _c , therefore, to reach the desired course, the fighter turns around Δψ _and = ψ _Т -ψ _о .

The simulation results of all the described guidance options are presented in FIG. 5-8, which show the trajectory of the aircraft pointing (dashed line) to a moving target (solid line).

The results of the first variant of interception simulation by the method (3) of the target are shown in FIG. 5.

The results of the second variant of target interception simulation during linearization of the guidance algorithm (3) are shown in FIG. 6.

The results of the second version of the simulation of target interception with new initial ones, satisfying the linearization conditions, at which (4) was obtained, are shown in FIG. 7.

The simulation results of the third embodiment (modified algorithm) of interception are shown in FIG. 8.

As can be seen from FIG. 6, when the fighter is guided at the rate calculated in accordance with equation (4), interception of the target occurs. This is understandable, since when deriving equation (4) from system (3), the assumption is made that guidance is carried out on overtaking or oncoming courses. In this regard, the initial position of the fighter was changed so that it provided guidance of the fighter with a course close to the oncoming relative to the target (see Fig. 7)

As can be seen from FIG. 8, when fighter is guided at the heading calculated in accordance with equation (11), the fighter’s paths and targets are identical to their trajectories in the first interception variant. Thus, aiming at an air target in accordance with the proposed method ensures the movement of the fighter in exact accordance with the system of equations (3) with the possibility of obtaining the desired course by simple calculations.

Detailed modeling of the process of intercepting an air target according to the modified method with arbitrary initial data showed that the aircraft is guided with high accuracy and has good stability.

Thus, the modified interception method in comparison with the known method is characterized by increased information content and ease of calculating the required course of the induced aircraft and the guidance time.

Literature

1. Aviation systems of radio control: a textbook for military and civilian universities and research organizations. / IN AND. Merkulov, B.C. Chernov, V.A. Gandurin, V.V. Drogalin, A.N. Savelyev. Ed. IN AND. Merkulova. - M.: Publishing. VVIA them. prof. NOT. Zhukovsky, 2008. p. 176, 190, 218, 219, 228-231.

2. Reference officer of the Air Force and Air Defense Forces / ed. I.P. Azarenka. - Minsk: command of the Air Force and Air Defense Forces, 2009 338.

3. Kuzmin S.Z. Digital radar. Introduction to the theory. - Kiev: KVSCh Publishing House, 2000. p. 183-217.

Claims (1)

The method of intercepting an air target by an aircraft, which consists in measuring the polar coordinates of the target and the aircraft in a horizontal plane, using the control point (PU) to evaluate the polar and rectangular coordinates of the target and the aircraft, the target and the speed of the aircraft and the target, and set a fictitious point A located on the line coinciding with the velocity vector V _c plane at a distance _of D from the plane determined desired rate value ψ _T of the aircraft, the value of which is transmitted to the UE on a plane, where it is measured _with the current rate ψ and determining pairs Control meter Δψ = ψ _T -ψ _c, administers motion trajectory plane, characterized in that the PU to estimate ψ course _with the aircraft, the point A is selected by setting rectangular coordinates
z _a = z _c + Д _з sinψ _T ,
x _a = x _c + D _s cosψ _T ,
where x _a , z _a , x _c , z _c are the estimates of the rectangular coordinates of point A and the plane, the angle of sight of the target relative to point A is calculated, the angles of the bearing φ _a and φ _{c are} determined, which are the angles between the velocity vectors V _c and V _{c of the} point A and the target, respectively, and the line of sight “point A - target”, determine the value of the required course ψ _T of the aircraft motion from the condition that the projections of the velocities of the speeds of point A and the target perpendicular to the line of sight “point A - target” are equal, the pilot estimates the expected results of solving the interception problem airborne target aircraft with Using a visual display on the screen of the indicator projected target position in the distal end of step guidance coinciding with the pickup point, and guidance of time for which the computing system PU are rectangular coordinates of the point of interception of the formulas:
x _yt = x _a + V _c t _н cosψ _T , z _ut = z _a + V _c t _н sinψ _T
or
x _yt = x _c + V _c t _n cosψ _c , z _ut = z _c + V _c t _n sinψ _c
and determine the guidance time

where x _c , z _c are the estimates of the rectangular coordinates of the target, ψ _c is the target's course, these data are output and transmitted via the command radio control line to the display system on the plane.

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