EP0401693B1 - Method for improving the accuracy of hit of a controlled missile - Google Patents

Description

The invention relates to a method according to the preamble of claim 1.

As a rule, a missile which is intended to fly to a specific target will be equipped with a seeker head which is capable of identifying the target itself and generating guide signals for the pursuit of this target after the target perception, as in DE-A1- 33 03 763, described in DE-A1-15 78 299 or in DE-A1-28 30 502. This has the advantage of tracking the missile into the target position of the target point by regulating the influences of path disturbances, in particular air currents acting transversely to the trajectory, even if the target performs evasive maneuvers. Here, as shown in DE-C1-18 15 727, to achieve a more favorable hit position depending on the sensor-determined approach to the target object, a path advance specified in the control program can be provided by switching the squint angle during the remaining time of the target approach.

In other cases, such as with the guidance of the guide beam according to DE-A1-29 51 941, the target point is determined by reconnaissance means arranged outside the missile with transmission of target and / or correction information to the projectile already in the approach. Fixed orbital data for stationary targets can also be corrected as a function of the missile-related path deviations of the missile. Such an autonomous missile with control that does not seek a target along a preprogrammed or externally predetermined trajectory is equipped for navigation with inertial systems or corresponding sensors which provide the current actual position and thus the deviation from the known target trajectory in order to provide the missile's autopilot with this error information Food. This causes a real trajectory to the specified target point via the missile positioning system, despite disturbances acting transversely to the trajectory (such as air currents in particular).

To improve the ammunition effect in the target as a result of increased impact speed, an additional engine acting in the longitudinal direction is fired or activated, for example, only shortly before the target hits.

The invention has for its object to provide a method of the type mentioned, with which a target control of a fixed or a movable target with high accuracy is possible without the missile is equipped with a seeker head, a high accuracy is also achieved , if the programmed flying missile is affected by path disturbances such as strong ground winds.

The method with the features of claim 1 solves this problem.

The final phase path reserve provided according to this solution is therefore of a different nature than the previously known squint angle change in order to achieve a more favorable hit position, controlled from the sensor-based approach to the target. Rather, in the present solution it is a question of compensating the lateral forces acting on the trajectory, which can be determined on board the missile via the control deviation of the target trajectory, in their influence on the changed longitudinal velocity of the missile in such a way that before or at least during the final phase acceleration the missile is forced to change orbit contrary to the resulting path shift.

The flight path ahead can be calculated in advance in an orbital extrapolation model operated on board the missile in accordance with the respective ideal target position and the current actual position of the missile, taking into account also the influences of other flight condition variables. The target path correction in the sense of reducing this error is then derived from the resultant hit error. To minimize the remaining hit error, such a path extrapolation can expediently be repeated in a plurality of iterations. Here, ie at The trajectory extrapolation carried out in several iterations preferably takes into account the future acceleration profile of the missile, so that, including future trajectory disturbances and taking current external trajectory disturbances into account, a target trajectory results with a minimal hit error. The target path optimized in this way serves as a reference or target specification for an autopilot of the missile.

Fig.1

eine Blockschaltung zur Verdeutlichung des Verfahrens zur Verbesserung der Treffgenauigkeit eines programmiert fliegenden Flugkörpers, und

Fig.2

eine grafische Darstellung des Einflusses einer Bahnstörung auf die Flugbahn des programmiert fliegenden Flugkörpers bzw. auf seine Treffgenauigkeit.

Further details, features and advantages of the method according to the invention are described below with reference to the drawing. It shows:

Fig. 1

a block circuit to illustrate the method for improving the accuracy of a programmed flying missile, and

Fig. 2

a graphic representation of the influence of a path disturbance on the flight path of the programmed flying missile or on its accuracy.

If a missile does not have a seeker head because, for example, this should be saved for cost reasons, or because the seeker head would not be suitable for recognizing the target to be combated, or because the geodetic location of the target to be combated is known from prior clarification, which is particularly important for stationary targets such as bridges, buildings or the like. the case is, the missile can only move along a programmed trajectory to the target to be fought. It is assumed that the programmed flying missile both its ideal target path, which leads it to the target to be fought, from pre-programmed data or by transmission via a so-called. Data-link knows, and also has sensors and / or an inertial navigation unit that delivers the actual position to the missile. This situation is shown schematically in a block diagram in FIG. A web extrapolation model 10 is closed with a control unit 12 a self-contained system connected, which is indicated by the two arrows 14 and 16. The web extrapolation model 10 has two inputs 18 and 20 and one output 22. The input 18 is connected to the output 24 of a reference unit 26, which is indicated by the arrow 28. The reference unit 26 has an input 30 through which data preprogrammed into the reference unit 26 is input.

The output 22 of the orbit extrapolation model 10 is connected to an input 32 of an autopilot 34, which is illustrated by the connecting line 36. The autopilot 34 has a second input 38 and an output 40, the output 40 of the autopilot 34 being connected to an actuating system 42. The control system 42 is connected to the missile dynamics illustrated by block 44. The output 46 of the missile dynamics 44 represents the trajectory of the missile. This trajectory is characterized by the trajectory disturbances indicated by the arrow 48, which are, for example, gusts of wind, ground wind or the like. acts, influences. Sensors 50 serve to detect the flight path or the flight path disturbances, the output 52 of the sensors 50 being connected to the second input 38 of the autopilot 34. In addition, the output 52 of the sensors 50 is connected to an inertial navigation unit 54, at the output 56 of which the actual position of the missile is given. The actual position of the missile is entered through the input 20 of the orbital extrapolation model 10 and the ideal target path of the missile is entered through the input 18 of the orbital extrapolation model 10. The output 22 of the orbit extrapolation model 10 represents the target path of the missile, while the arrow 14 between the orbit extrapolation model 10 and the control unit 12 represents the hit error.

Depending on the accuracy of the sensors 50, the autopilot 34 and the positioning system can be used 42 to influence the missile dynamics so that the real trajectory of the missile despite the external disturbances - which are indicated by the arrow 48 - leads to the target to be combated.

• 1. Bei der Bewegung des Flugkörpers in einem Windfeld ergibt sich ein resultierender inertialer Geschwindigkeitsvektor v als Überlagerung, d.h. als Vektorsumme des Geschwindigkeitsvektors v_a gegenüber ruhender Luft und des Windgeschwindigkeitsvektors v_w . In Fig.2 ist eine Vektordarstellung in einer Horizontalebene x-y gezeichnet, entsprechendes gilt selbstverständlich auch für die zu dieser Horizontalebene senkrechte Vertikalebene. Ergibt sich nun in einem stationären Zielanflug der inertiale Bahnwinkel b₁ als resultierende Flugrichtung zum Ziel mit der Geschwindigkeit v_a1 und der Windgeschwindigkeit v_w zur resultierenden Geschwindigkeit v₁, so ändert sich bei Schuberhöhung die Geschwindigkeit v_a1 zur Geschwindigkeit v_a2, wobei der Windgeschwindigkeitsvektor v_w gleich bleibt. Das bedeutet jedoch, daß die aus v_a2 und v_w resultierende Geschwindigkeit v₂ als neue inertiale Geschwindigkeit auftritt, die mit der x-Achse einen von b₁ abweichenden Winkel b₂ einschließt. Es ergibt sich also ein Winkelfehler Δb als Differenz zwischen den beiden genannten Winkeln b₁ und b₂ in der Zielpunktrichtung und folglich eine Verringerung der Treffgenauigkeit, da Bahnkorrekturen des beschleunigten Flugkörpers im Ergebnis zu großen Ablagen führen.
• 2. Ein zur Geschwindigkeitserhöhung dienendes Triebwerk des Flugkörpers wird typischerweise seine Schubkraft in Flugkörper-Längsrichtung, d.h. in Richtung des Vektors v_a entwickeln. Befindet sich der Flugkörper vor der Beschleunigungsphase im Schiebeflug, so bewegt er sich inertial in der in Fig.2 dargestellten Horizotalebene x-y nicht in der Flugkörper-Längsrichtung sondern in einer von der Windgeschwindigkeit v_w abhängigen resultierenden Bahnrichtung, die durch den Autopiloten 34 (s. Fig.1) in Zielpunktrichtung gedreht wird. Wird nun der Flugkörper beschleunigt, so wird er nicht in der inertialen Bahnrichtung zum Ziel sondern in seiner Flugkörper-Längsrichtung beschleunigt und kann nur unter unrealistischen Manövereingriffen des Autopiloten 34 zum zu bekämpfenden Ziel korrigiert werden, was ebenfalls zu einer Verringerung der Treffgenauigkeit führt. Entsprechendes gilt selbstverständlich auch für die Bewegung in der Vertikalebene.

If the missile is to be strongly accelerated to increase the impact velocity at the target to be combated in the end phase of the trajectory in order to improve the effectiveness of the missile, the following problems arise in a missile without a search head:

• 1. When the missile moves in a wind field, a resulting inertial speed vector v results as a superimposition, ie as a vector sum of the speed vector v _a compared to still air and the wind speed vector v _w . A vector representation is drawn in a horizontal plane xy in FIG. 2; the same applies of course also to the vertical plane perpendicular to this horizontal plane. Now results in a stationary target approach the inertial orbit angle b₁ as the resulting flight direction to the target with the speed v _a1 and the wind speed v _w to the resulting speed v₁, so the speed v _{a1 changes} to the speed v _a2 when the thrust is increased, the wind speed vector v _w stays the same. However, this means that the velocity v₂ resulting from v _a2 and v _w occurs as a new inertial velocity, which includes an angle b₂ deviating from b₁ with the x-axis. So there is an angle error Δb as the difference between the two angles b₁ and b₂ mentioned in the direction of the target point and consequently a reduction in the accuracy, since path corrections of the accelerated missile result in large deposits.
• 2. A missile engine used to increase the speed typically becomes its thrust develop in the longitudinal direction of the missile, ie in the direction of the vector v _a . If the missile is in the push flight before the acceleration phase, it moves inertially in the horizontal plane xy shown in FIG. 2 not in the longitudinal direction of the missile but in a resulting orbital direction dependent on the wind speed v _w , which is determined by the autopilot 34 (see FIG. Fig.1) is rotated in the direction of the target point. If the missile is now accelerated, it is accelerated not in the inertial orbital direction to the target but in its longitudinal direction and can only be corrected under unrealistic maneuvering by the autopilot 34 to the target to be combated, which likewise leads to a reduction in accuracy. The same naturally also applies to the movement in the vertical plane.

The two problems mentioned, which lead to a deterioration in the accuracy of the hit, can be solved if the target path of the missile, which is indicated by the connecting line 36 between the orbit extrapolation model 10 and the autopilot 34 in FIG. 1, occurs before and during the acceleration of the missile a path reserve is provided, which compensates for the error sketched for the horizontal plane in FIG. 2 by trajectory disturbances (see arrow 48 in FIG. 1). For this purpose, in the rail extrapolation model 10, the flight path ahead is calculated in advance according to the ideal target position (input 18 of the rail extrapolation model 10 in FIG. 1) and according to the current actual position (input 20 of the rail extrapolation model 10 in FIG. 1), and according to further flight state variables. From the resultant predicted hit error, 12 path corrections of the target path are determined in the web extrapolation unit via the control unit, which lead to a reduction in the hit error. With this orbit extrapolation, which preferably runs in several iterations, the future acceleration profile of the Missile taken into account so that a target trajectory is created, which, including future trajectory disturbances and current external trajectory disturbances, leads to a minimization of the hit error. This optimized target path (connecting line 36 in FIG. 1) serves the autopilot 34 as a reference or target specification.

Claims (5)

1. Method of improving the target accuracy of a missile without homing head, which may be controlled along a desired flight path, may be post-accelerated in the final phase of the target approach and may be influenced by external current-related disturbances in flight path, characterised in that the desired flight path of the controlled missile without homing head is provided with a path guidance dependent on the given path disturbances and on its longitudinal acceleration profile.
2. Method according to Claim 1, characterised in that the anticipated flight path is calculated beforehand in a path extrapolation model in accordance with the ideal desired position and the current actual position and in accordance with further flight variables, wherein path corrections to the desired path are determined from the forecast target errors resulting herein in a path extrapolation unit via a control unit to reduce the target error.
3. Method according to Claim 1 or 2, characterised in that the path extrapolation is carried out in several iterations.
4. Method according to Claim 3, characterised in that in the path extrapolation carried out in several iterations, the future acceleration profile of the missile is taken into account, thus resulting in a desired flight path with minimum target error to include future path disturbances and take into account current external flight path disturbances.
5. Method according to one of the preceding claims, characterised in that the optimised desired path acts as a reference or desired preset value for an autopilot of the missile.

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