Tracking maneuvering targets. Automatic target tracking

All-round detection radar (SRS) is designed to solve the problems of searching, detecting and tracking air targets, determining their nationality. The SRS implements various survey procedures that significantly increase noise immunity, the probability of detecting low-observable and high-speed targets, and the quality of tracking of maneuvering targets. The developer of the RLO is the Research Institute of Instrument Engineering.

The combat control post (PBU) of the air defense system as part of the grouping carries out, according to the coordinate information of the SART, the linkage and tracking of the routes of the detected targets, the opening of the air enemy strike plan, the distribution of targets between the air defense systems in the group, the issuance of target designations of the air defense systems, the interaction between the air defense systems conducting combat operations, as well as interaction with other forces and means of air defense. A high degree of automation of processes allows the combat crew to focus on solving operational and operational-tactical tasks, using the advantages of man-machine systems to the fullest extent. The PBU provides combat work from higher command posts and, in cooperation with the PBU, controls of neighboring groups.

The main components of the S-ZOOPMU, S-ZOOPMU1 air defense systems:

Multifunctional radar for target illumination and missile guidance(RPN) receives and develops target designations from 83M6E controls and attached autonomous sources of information, detection, incl. in autonomous mode, capturing and auto-tracking targets, determining their nationality, capturing, tracking and guiding missiles, highlighting fired targets to ensure the operation of semi-active homing heads of guided missiles.

The on-load tap-changer also performs the functions of an ADMS command post: - according to information from PBU 83M6E, it controls the ADMS assets; - selects targets for priority firing; - solves the launch problem and determines the results of firing; - provides information interaction with the PBU of 83M6E controls.

The all-round view increases the search capabilities of air defense systems in the independent conduct of hostilities, and also ensures the detection and tracking of targets in sectors that, for some reason, are inaccessible to the SART and RPN. The 36D6 radar and the 5N66M low-altitude detector can be used as an autonomous attached tool.

Attached autonomous means of detection and target designation

Launchers Launchers (up to 12) are designed for storage, transportation, pre-launch preparation and missile launch. Launchers are placed on a self-propelled chassis or road train. Each launcher has up to 4 missiles in transport and launch containers. Provides long-term (up to 10 years) storage of missiles without any maintenance measures with the opening of containers. The developers of the launcher are the design bureau of special engineering, the design bureau of the Nizhny Novgorod Ministry of Health.

Launchers

rockets- single-stage, solid-propellant, with a vertical start, equipped with an onboard semi-active radio direction finder. The lead developer of the rocket is MKB Fakel.

83M6E controls provide: - detection of aircraft, cruise missiles in the entire range of their practical application and ballistic missiles with a launch range of up to 1000 km; - route tracking up to 100 targets; - management of up to 6 air defense systems; - maximum detection range - 300 km.

The S-ZOOPMU1 air defense system is a deep modernization of the S-ZOOPMU and is actually a transitional link to third-generation systems.

S-ZOOPMU1 provides: - hitting targets at ranges from 5 to 150 km, in the range of altitudes from 0.01 to 27 km, speed of hit targets up to 2800 m/s; - defeat of non-strategic ballistic missiles with a launch range of up to 1000 km at ranges of up to 40 km when receiving target designation from 83M6E controls; - simultaneous firing of up to 6 targets with guidance of up to 2 missiles for each target; in the basic type of missiles - 48N6E; - rate of fire 3-5 sec.

If necessary, the S-ZOOPMU1 air defense system can be modified to use the 5V55 missiles of the S-ZOOPMU system.

The ancestor of the S-ZOOP family - the S-ZOOPMU air defense system provides:-> defeat targets at ranges from 5 to 90 km, in the altitude range from 0.025 to 27 km, the speed of hit targets up to 1150 m / s; - defeat of ballistic targets with a launch range of up to 300 km at ranges of up to 35 km with target designation from controls; - simultaneous firing of up to 6 targets with guidance of up to 2 missiles for each target; - basic type of missiles 5V55; - rate of fire 3-5 sec.

ALTEC-300

Educational and training complex

MAIN CHARACTERISTICS The training complex "ALTEK-300" is part of the additional means of the S-300PMU1, S-300PMU2 anti-aircraft missile systems and 83M6E, 83M6E2 controls and is intended for training and training combat crews without spending the resource of combat assets. "ALTEK-300" is implemented on the basis of a local area network of personal electronic computers (PC) of general use, operating under the Microsoft Windows XP operating system using the Microsoft SQL Server DBMS and emulating, using specialized software, workstations of air defense systems and control systems with their display/control bodies. The specialized software of the "ALTEK-300" complex includes: - basic models of anti-aircraft missile system means and basic models of control means, reflecting the properties and algorithms of functioning of means in various conditions; - basic models of air attack means, reflecting their combat properties; - the basic model of the area of ​​possible hostilities, reflecting its physical and geographical features; - programs for preparing initial data for training combat crews; - a database designed to store options for initial data for conducting and documenting training; - multimedia textbook. TECHNICAL SUPPORT During the life cycle of the training complex, it is provided for its maintenance and refinement (at the request of the customer), including: - expanding the range of basic models of air attack weapons that reflect their combat properties; - Refinement of basic models of anti-aircraft missile systems and basic models of controls, reflecting the properties and algorithms of the functioning of the upgraded means in various conditions; - installation of a basic model of the area of ​​possible hostilities, reflecting its physical and geographical features using a digital map of a given defense area; Regarding the modernization of the equipment of the training complex, it is envisaged: - deployment of a mobile version of the complex based on portable computers. MAIN ADVANTAGES Due to the use of specialized software for training and education of combat crews and through the use of general-purpose personal electronic computers in the ALTEK-300 complex instead of real equipment for air defense systems and control systems, the following is provided: - reduction in the cost of training combat crews by more than 420 times in comparison with the costs when using real equipment for the preparation of combat crews; - saving the resource of fixed assets of air defense systems and control systems in the preparation of combat crews - up to 80%; - reduction in the time of performing the following operations compared to the standard one: - formation of a tactical situation for training - 10-15 times; - evaluation of the results of training training of combat crews - 5-8 times; - study of theoretical material to a predetermined level in comparison with the traditional method of preparation - 2-4 times; - training of personnel of combat crews to fulfill the standards for combat work at a given level - by 1.7-2 times. At the same time, the number of tactical situational tasks performed by a trainee per unit of time using a training complex is 8-10 times greater than when working on real equipment with the possibility of simulating such a tactical situation that cannot be created on existing training systems of real equipment.

The maneuver of the target in the horizontal plane is reduced to a change in course and flight speed. The influence of the maneuver of an aerial target on the first and second stages of guiding a fighter by the "Maneuver" method manifests itself in various ways.

Let us assume that guidance is carried out at the first stage, when the air target and the fighter were respectively at the points AT and BUT (Fig. 7.9.), And their meeting was possible at the point C o .

Rice. 7.9. Influence of target maneuver in the horizontal plane

to the flight path of a fighter

If the air target is at the point AT made a maneuver in the course and in time t turned to a corner w c t , then in order for the fighter to follow a tangent to the turn arc of the second stage of guidance, its course must change by the angle w and t . After the air target has completed the maneuver, a meeting with it will become possible at the point With , and the path length of the air target to the point will change to DSc.

If we imagine that the turn start point is moving along with the CC, located relative to it at the same interval and distance as the fighter at the start of the turn, then the fighter is guided to this point by the "Parallel approach" method. If the CC is at a long distance Before from a fighter, compared with which the interval I and predicted turning distance dupr can be neglected, then in general the properties of the "Maneuver" method are close to those of the "Parallel approach" method.

To a later meeting of a fighter with a target (DSc > 0) leads her lapel from the fighter (DΘ and > 0) , and turning towards the fighter leads to an earlier encounter. Therefore, the countermeasure against the maneuver of the target heading, as in the case of guidance by the "Parallel approach" method, can be the simultaneous guidance of groups of fighters on it from different sides.

As the distance to the CC decreases, the difference between the properties of the "Maneuver" method and the properties of the "Parallel rendezvous" method manifests itself more and more. During the turnaround time of the VC, the fighter needs to turn around at increasingly large angles, that is, its angular velocity w increases.

Value change w and when flying a fighter on a collision course with an air target (UR = 180°) characterizes the dependence graph of the ratio of angular velocities w and / w c from the range, expressed in fractions of the lead turn distance D/Dupr.

As can be seen from the graph, at long ranges (D / Dupr = 5÷ 10) attitude w and / w c differs slightly from unity, that is, the angular velocity of the fighter is slightly different from the angular velocity of the maneuvering target. With a decrease in range, up to about three Supr , the value of wi grows rapidly, and when the fighter approaches the turn start point (D / Dupr = 1)w and increases to infinity.

Thus, when pointing by the "Maneuver" method at a maneuvering AT, it is almost impossible to bring the fighter to the turn start point with the calculated radius.

Rice. 7.10. Dependence of the ratio of angular velocities w and / w c during target maneuver

at the first stage of guidance in relation to D / Dupr

During the guidance process at the first stage, the air target can maneuver repeatedly. So, for example, an air target at a point IN 1 can turn on a fighter, resulting in a point A1 it must be turned away from its previous course and the direction of the previously envisaged turn must be changed. As a result, the fighter's trajectory at the first stage of guidance turns from a straight line into a complex line consisting of turning arcs with a variable radius and straight line segments between them. All this complicates the flight to air combat.

The influence of the maneuver of an air target at the second stage of guiding a fighter by the "Maneuver" method will be considered using Figure 7.11.:

Rice. 7.11. Influence of air target maneuver in the horizontal plane

at the second stage of guidance by the "Maneuver" method on the flight path of a fighter

Let us assume that at some moment of the second stage of guidance, the fighter and the air target are, respectively, at the points BUT and AT and to meet the target at the point So the fighter performs a turn with a radius Ro and angular velocity w and = Vi/Rо .

If for some period of time Dt air target will change direction of flight by an angle w c × Dt , then meeting with it will become possible at the point With . To get to this point from the point BUT the fighter would need to perform a turn with a different radius R . But in advance for the time Dt he would have to additionally tighten the corner w and D × Dt .

Thus, the maneuver of an air target at the second stage of guidance leads to the appearance of an additional angular velocity of the turn of the fighter w and D . The smaller the remaining turning angle UR fighter, the greater the value w and D , and as the fighter approaches the end point of the turn w and D increases to infinity.

Thus, it is practically impossible to bring a fighter to a predetermined position relative to a maneuvering air target at the second stage of guidance by the "Maneuver" method.

In this regard, in the case of maneuvering an air target, at the second stage, as a rule, they switch to guiding a fighter using the Chase method.

As a result of the primary processing of radar information, two streams of target marks arrive at the input of the autotracking algorithm:

"true targets", grouped near the actual position of the targets;

"false targets"", one of which is tied to areas of interference and reflections from local objects, and the other is evenly distributed throughout the station's field of view.

If it is decided that a certain set of marks received by each in its radar survey refers to the same trajectory, then the next task is to evaluate the parameters of this trajectory, which consists in calculating the parameters considered in Section 2.2 X 0 ,At 0 ,H 0 ,V x ,V y ,V H ,a x ,a y and a H. If there are two marks about the target as initial coordinates X 0 ,At 0 and H 0 the coordinates of the last mark are received, the components of the speed V x , V y and V H are calculated in the same way as with auto-capture of the trajectory.

If a larger number of marks are distinguished, it is possible to switch to a more complex model of target movement and smooth the trajectory parameters. Smoothing is performed in order to reduce the impact of radar target coordinate measurement errors on tracking accuracy. The most common in ACS are a linear model of target movement and successive smoothing of trajectory parameters.

The essence of the successive smoothing method is that the smoothed values ​​of the trajectory parameters in the next k-th range are determined by the smoothed values ​​obtained in ( k-1)-th review, and the results of the last k th observation. Regardless of the number of observations made, only the previous estimate and the result of a new observation are used in the next calculation cycle. At the same time, the requirements for the capacity of storage devices and the speed of the equipment are significantly reduced.

The final expressions for smoothing the position and velocity in the kth radar survey are as follows:

It can be seen from these formulas that the smoothed value of the coordinate is equal to the sum extrapolated to the moment k-observations of the smoothed coordinate U* KE and taken with a coefficient  k deviations of the extrapolated coordinate from the measurement result.

Smoothed speed value in k th review V * U K is the sum of the smoothed speed V * U K-1 in ( k-1)-th review and taken with a coefficient  k speed increment that is proportional to the deflection.

U=U K- U KE.

H

Rice. 2.5. Smoothing of target trajectory parameters.

and Fig. 2.5 shows the section of the target trajectory, the true positions of the target at the moments of location and the results of measurements. Segments of straight lines depict the trajectory of movement calculated by the ACS computer when coordinates are not smoothed (velocity components in each survey are determined by the results of the last two observations). The target is moving in the direction of the velocity vector. At the moment of taking coordinates, the velocity components are recalculated, the current coordinates and the direction of target movement change abruptly.

The dotted line in Fig. 2.5 means the smoothed target trajectory calculated in the ACS computer in k th review. Due to the fact that the coefficients of the smoothed coordinates  k and  k lie within 0...1, the smoothed initial coordinate is in the interval U* KE ... U K, and the smoothed speed is V * U K-1... V * U K.

It is proved that for a rectilinear uniform motion of the target, the tracking errors will be minimal if the coefficients  k and  k are calculated according to the formulas:

(2.9)

Figure 2.6 shows the dependence  k and  k from review number k. It can be seen from the graphs of the figure that the coefficients asymptotically approach zero. In the limit at k This achieves the complete elimination of target tracking errors. In practice, there are always deviations of the target trajectory from a straight line.

Therefore, the values ​​of the coefficients  k and  k decrease only to certain limits.

Qualitatively, the effect of smoothing on the accuracy of target tracking can be estimated using Fig. 2.7. In the area of ​​rectilinear motion, the error of the smoothed target coordinates is less than the unsmoothed ones: segments of dotted lines are closer to the true trajectory of the target than segments of solid lines. In the maneuver section, due to the discrepancy between the true nature of the target’s movement and the hypothetical one, dynamic tracking errors occur. Now segments of solid lines more accurately determine the actual position of the target compared to segments of dashed lines.

In the air defense automated control system, when tracking non-maneuvering targets, the choice of coefficients  k and  k produced in various ways: they can either be recalculated from initial to some final values, or remain unchanged during the entire maintenance period. In the latter case, the optimal successive smoothing turns into the so-called exponential smoothing. Target maneuver detection can be performed visually by the operator or automatically. In both cases, the target is considered maneuvering if the measured target coordinate differs from the extrapolated one by an amount that exceeds the allowable coordinate measurement errors.

W

Rice. 2.6. Dependence of smoothing coefficients on K.

Knowing the trajectory parameters allows you to calculate the current position of the target at any time t:

Rice. 2.7. Effect of Smoothing Trajectory Parameters on Target Tracking Accuracy

Usually, the calculation of the current (extrapolated at a given point in time) coordinates of the target is timed to the moments of issuing information to indicators, communication channels, memory zones of other algorithms, etc. The calculation of the predicted values ​​of the target coordinates is carried out according to the formulas:

(2.10)

where t y- lead time, counted from the current moment t.

Usually t y when assessing the air situation, it is set by commanders, and when solving other data processing tasks, it is read from the permanent memory of the ACS computer.

The final stage of target tracking is the solution of the problem of correlating newly appearing marks with existing trajectories. This problem is solved by mathematical gating of airspace areas. Its essence lies in the machine verification of the fulfillment of equalities, with the help of which it is established that the mark belongs to the area under study. In this case, rectangular or circular gates are most often used. Their parameters are shown in Figure 2.8.

Let be X uh, At E - extrapolated target coordinates at some point in time t. To find out which of the marks received in the next survey belongs to this trajectory, it is necessary to check the conditions:

P

Rice. 2.8. Strobe parameters

When using rectangular gates -

|X 1 -X E |  X pp; | Y 1 -Y E |  Y pp; (2.11)

when using a circular strobe -

(X i – X E) 2 + ( Y i – Y E) 2  R str, (2.12)

where X page, Y str - dimensions of a rectangular gate;

R str - the size of the circular gate.

As a result of the enumeration of all possible pairs of "trajectory-mark" in each survey, it is established which marks continue the existing ones, and which ones initiate new traces.

From the description of target trajectory tracking algorithms, it can be seen that the processing of information about the air situation is a very laborious process that requires large amounts of RAM and computer speed of the automated control system.

The maneuver of the tracked target, which is longer than the period of updating information at the input of the SVR, manifests itself in the appearance of a systematic component in the dynamic filtering errors.

Let us consider as an example the process of constructing a target trajectory, which, up to the point B(Fig. 12.15) moved evenly and in a straight line, and then began the maneuver with a large (1), medium (2) or small (3) overload (dash-dotted lines). Based on the estimation of the parameters of the rectilinear section of the trajectory based on the results of filtering n measurements (marked with a circle in the figure), the current coordinates of the target (dashed line) and the extrapolated coordinates on ( n+1)th review (triangle).

BUT

B

As can be seen from the figure, after the start of the maneuver, the current coordinates of the target given to consumers will contain a dynamic error, the value of which is the greater, the greater the target overload during the maneuver and the space survey period.

In order to automatically track the target under these conditions, it is necessary, firstly, to detect (reveal) the maneuver and, secondly, abandoning the hypothesis of rectilinear and uniform target movement, determine the maneuver parameters and, on this basis, use a new target movement hypothesis.

There are a number of methods for detecting a maneuver based on the results of discrete measurements of target coordinates:

1. The basis for terminating filtering according to the hypothesis of rectilinear uniform motion may be the excess of the modulus of the discrepancy of some constant value. In this case, a necessary condition for continuing filtering after receiving n-th mark can be represented in the following form:

; (1)

where: Δ P, Δ D- constants that determine the allowable value of the discrepancy and depend on the radar survey period and the accepted value of the target overload during the maneuver;

P n , D n- bearing and range values ​​measured in the n-th survey;

, - extrapolated at the time of the n-th measurement of the bearing and range values.

2. With higher requirements for the quality of detecting a maneuver in a horizontal plane under conditions of tracking trajectories in a rectangular coordinate system, the permissible value of the discrepancy is determined on each survey and the problem is solved as follows:

a) based on the results of each measurement of coordinates, the residual modules of extrapolated and measured values ​​of coordinates are calculated

;

;

b) the variance of errors of discrete measurements is calculated

where σ D, σ P- root-mean-square errors of discrete measurement of range and bearing;

c) the variance of extrapolation errors is calculated

,

d) the variance of the total error of coordinate measurement and extrapolation is calculated

(5)

e) values ​​are compared d and , where is a coefficient chosen for reasons of ensuring an acceptable probability of false detection of a maneuver.

If, by comparison, it turns out that d> , then the decision "waiting for maneuver" is made. If the inequality is satisfied for the second time, then the decision "maneuver" is made and the filtering of the trajectory parameters according to the hypothesis used is terminated.

3. Another approach to the choice of a maneuver detection criterion is also being used. In each survey, the autocorrelation function of the residuals of polar coordinates in the previous and current surveys is calculated

,

If there is no maneuver, then Δ D n and Δ P n are independent from survey to survey and the autocorrelation functions of residuals are small or even equal to zero. The presence of a maneuver significantly increases the mathematical expectation of the residual product. The decision to start the maneuver is made when the autocorrelation functions exceed a certain threshold level.

SECOND STUDY QUESTION: Tracking the target on the maneuver.

In the simplest case, when the start of a maneuver is detected after the (n + 1)-th target exposure at two points - the estimate of the coordinates in the n-th survey (open circle) and the measured coordinates in ( n+1)-th survey (solid circle) calculates the target's velocity vector, which can be used to compute current coordinates and extrapolated coordinates to ( n+2) th review. In the future, to build the target trajectory and calculate the extrapolated coordinates, the target coordinates measured in the current and previous surveys are used. A filter that works according to this algorithm is called a two-point extrapolator.

When using such an extrapolator, the deviation of the extrapolated coordinates from the true position of the target ( L 1 , L 2 , L 3) with a long review period and large target overloads on a maneuver, it can be very significant; in this case, with large errors, the current coordinates of the target will be given to consumers. Large extrapolation errors can cause the next target mark to be outside the boundaries of the autotracking strobe. Since false marks are usually present within the strobe, one of them will be selected and used to continue the trajectory in the false direction, and autotracking of the true target will be disrupted.

During a long maneuver with a constant overload, the target tracking accuracy can be improved by determining the rectangular components of the target acceleration , according to the first three marks obtained on the curved section of the trajectory, and further filtering the acceleration. This task is solved using "α-β-γ"- filter, the recurrent algorithm of which, in terms of estimating the coordinates and the rate of their change, remains the same as in "α-β"- filter, and the target acceleration estimate, for example, by the coordinate X upon receipt of the mark in n th review is calculated by the formula