DE19638968A1 - Fighting method for approaching flying object - Google Patents

Abstract

The method involves detecting an approaching flying object (40) by a device of a sensor system with large view range. The recorded image data is processed by a computer device (6, 18), the object is fought with a weapon according to the recorded image data. The object is passively detected by the sensor system with a high resolution, and the resolution of the recorded image data is reduced for an evaluation of whether the object should be fought, so that the data quantity for the evaluation is reduced. The processed image data are transmitted to an optical tracking sensor which follows the flying object position, to enable aiming at the object with the weapon.

Description

The invention relates to a method and an apparatus for Combating approaching missiles.

In a known method of this type, detection and Tracking ("tracking") the missile turned on a radar system sets which detects the target with radar and approaching flight bodies (planes, helicopters, rockets) at greater distances anti-missile and smaller distances (less than 2000 m) fought with machine guns. A disadvantage of this The method is, on the one hand, that radar systems have active sensors point, which emit electromagnetic waves and thus reveal, so that an opponent can grasp the location. On the other hand, a radar system sets complicated, voluminous ones and expensive technical equipment ahead. To a hit probability Combativity, especially for small fighters distance to achieve is a barrel weapon with extreme high sequence of shots required, with the continuous fire over a comparatively long time must be shot.

From DE 33 40 133 C2 a method is known which means Photodiode arrays in a 3-dimensional measuring room during a flight body can record, the amount of data generated by a Data reduction process is reduced. With this procedure should be from DE-OS 31 32 168 and DE 24 02 204 C3 known 2-dimensional method for determining the position of a Penetration point of a projectile from a measuring plane to one 3-dimensional measuring room can be expanded.

The invention is based, a method and a task Training device of the type mentioned so that the disadvantages mentioned are avoided and nevertheless a fighter missile approaching (missiles, airplanes, helicopters) is made possible with a high probability of being hit.

A method according to Patentan is used to solve this problem award 1 and a device according to claim 13.

Advantageous embodiments of the invention are in the sub claims under protection.

With the invention, the missile with a sensor system recorded in high resolution. This enables early detection of the missile still far away. The sensor system detected direction of approach of the missile is in itself known track sensor passed, but only one Ele vation and azimuth angle range with lower resolution white is routed. Since the track sensor only works in the "close range" the lower resolution is sufficient to record the flight body through the track sensor. Reducing the resolution causes a simple and quick transfer of the recorded data to the track sensor. By capturing with high resolution Despite the passive sensors, the necessary safety is guaranteed Guaranteed missile perception.

By using passive sensors that do not have an electroma emit magnetic waves, the electronic capture made impossible by the opposing defense. This increases the Probability of survival significantly, with simple structure and small volume of the optical sensor system used, which, for example, TV or infrared cameras for both Coarse detection with a large field of vision as well as for "tracking" with a long focal length (narrow field of view) against one much more complex and voluminous radar system essential to additional advantages result.  

The method and the device according to the invention enable the precise tracking of the weapon, so that the target with a short volley with a high probability of being hit can. This eliminates the use of a complex and expensive pipe weapon with high cadence or firing order in continuous fire.

The invention is based on schematic drawings closer to an embodiment with further details explained. Show it:

Figure 1 is a schematic representation in plan view of a device according to the invention.

Fig. 2 is an illustration of the device of Figure 1 Be tenansicht with a high block diagram with a relationship of a control computer and a fire control computer.

Fig. 3 is a path diagram, based on which the individual steps of the method are illustrated depending on the distance of the flying missile;

Fig. 4 schematically shows the subdivision into pixels and segments of an inventive captured image.

The device shown in FIGS . 1 and 2 has an optical sensor system with two fixed cameras 2 and 4 arranged parallel to one another at a distance from one another for detecting an approaching missile. The two cameras 2 , 4 are aligned in the same direction, and they have a large field of view A and B of z. B. 40 ° in azimuth and 8 ° in elec tion. The cameras 2 , 4 preferably each consist of a camera block with four camera modules, each camera module being formed from a CCD camera. Each camera module has a pixel field of 738 × 576. This results in a resolution of 0.014 °, ie approximately 0.8 'or +/- 0.4'. With such a high resolution, missiles can be recognized at an early stage, even if they are small in size and have a camouflage color. The early detection saves time for the evaluation of the image data.

The output signals of the cameras 2,4 to be entered as shown in FIG. 2 in a control computer 6, the more output signals from a track sensor 8 long focal length, that is with a small field of view C of z. B. 1 °.

The track sensor 8 includes a laser range finder (not shown separately), and the track sensor 8 is mounted together with this laser range finder on a platform 10 movable about two axes (azimuth axis and elevation axis). This platform is also equipped with two high-precision protractors of a known type (not shown) for detecting the pivoting movements of the platform 10 about the two axes, namely the axis of elevation e and the azimuth axis a.

The reference number 12 denotes an azimuth drive for the platform 10 for generating a tracking swivel about the azimuth axis a. Reference number 14 denotes an elevation drive for generating a tracking swivel about the elevation axis e of the platform 10 . Both drives 12 and 14 are controlled by the control computer 6 for tracking the platform 10 .

The output 16 of the control computer 6 leads to a fire control computer 18 , which acts on a gun 20 via a downstream control unit 19 . This barrel weapon 20 is mounted on a platform 22 which is pivotable about an azimuth axis a 'by means of an azimuth drive 24 . The azimuth drive 24 is controlled via the output line 26 of the fire control computer 16. Furthermore, there is an elevation drive 28 which can be controlled via an output line 30 and can pivot the barrel weapon 20 about an elevation axis e '.

The sensor system 2 , 4 and the track sensor 8 with computers 6 , 18 , barrel weapon 20 with platform 22 and the drives 24 and 28 can be mounted on an armored vehicle 32 .

The operation of the method and the device according to the invention will now be explained with reference to FIGS. 1 and 2, including FIG. 3. The output signals of the two cameras 2 , 4 are correlated in real time in the control computer 6, in order to thereby detect even the smallest movements (in the pixel area) and thereby an approaching missile, for. B. to detect a rocket early.

The direction of the flying missile can be determined from the position of the detected movement in the camera images evaluated by the control computer 6 . Known Track Senso ren require an accuracy of the direction of about +/- 3 mrad or +/- 10 '.

The evaluation of the output signals of the cameras 2 , 4 in the control computer 6 is preferably carried out according to the following method steps:

• 1. The signals from the individual cameras 2 , 4 or the individual camera modules of the cameras 2 , 4 are digitized in parallel. The amount of data generated here is in the order of 80 MB per second, for example. This amount of data results, for example, in the case of 2 × 4 camera modules with 738 × 576 pixels × 25 frames / second (81.08 MB), with one byte being stored for each pixel, which represents a gray level detected at the pixel.
• 2. In a first evaluation process, mean _values P _{xyref are} calculated for the individual pixels P _{xy of} the respective images captured by the cameras 2 , 4 , which are used for comparison with the current pixels. Slow changes such as changes in brightness, e.g. B. by clouds, and oscillating changes, for example trees swinging back and forth in the wind, are eliminated by comparing the current pixels with the corresponding mean values.
  The mean _{values are} calculated, for example, according to the following formula: P _{xyref, i} = P _{xyref, i-1} · Gew + P _xyakt (1-Gew), which is applied recursively, an average value P _{xyref, i of} a gray level of a pixel P _xy is determined from a previous mean value P _{xyref, i-1} and the currently measured gray level, where Gew is a weighting factor that has a value of 0.9, for example. The weighting factor Gew is preferably in the range from 0.7 to 0.95 and determines the temporal depth with which the measured images influence the mean value image.
• 3. In a second evaluation process, a differential image is obtained, in which the difference between the pixels of the average image P _xyref that of the current picture P _xyakt according to the following formula is determined: P _xyDiff = P _xyref -P _xyakt In this difference image P _xyDiff remain only still gray values of objects that have changed their shape or position on the image captured by cameras 2 , 4 . All other static objects are deleted from the difference image.
• 4. In a third evaluation process, the pixels or Pixel reduced to a bit of object signal, which is only the Contain information whether a pixel changes or has not changed. Each pixel has one such bit Object signal assigned, the bit is set when the gray level of the pixel above a predetermined threshold value, and the bit is deleted when the gray value is below the predetermined threshold. This will the amount of data in an image is reduced by a factor of 8 because each byte representing a grayscale by a single one Bit is replaced.
• 5. In a fourth evaluation process, the pixels reduced to one bit are combined into segments of, for example, 4 × 4 pixels. The image thus consists of a large number of segments S of the same size ( FIG. 4). A bit is in turn assigned to each segment S, the bit representing a reduced pixel which is set when a single pixel or pixel contained in the segment is set. The image composed of the reduced pixels thus reproduces the previously determined image of the objects which have changed in shape or position with a lower resolution. As a result of this reduction in resolution, the data obtained when combining 4 × 4 pixels are reduced by a factor of 16.
• 6. The previously processed parallel video signals are now merged, the previously separate object signals are summarized in data words containing the respective camera number, line information and column information. The information compressed in this way is filtered, and the pictorial representation of the detected object, which is referred to as a signature, is evaluated according to size, shape and movement on the image. If the signature does not correspond to a body of a predetermined size that is flying straight towards the sensor unit, it is deleted. The evaluation rules are to be created specifically for the type of object to be recorded. If an incoming rocket is to be fought, the image must be scanned for a gradually increasing circular disk. In addition, for example, only disks are selected which do not significantly change their position when approached, since a missile with a signature that moves strongly in the image would fly past its target or at least the missile defense device according to the invention. Another missile, in particular non-straight-line missiles, other assessment rules must be applied. This evaluation makes a pre-selection of the objects flying into the tax calculator. The data words containing the respective camera number, line information and column information indicate the elevation and azimuth angle range of the detected incoming missile, so that these angle ranges are passed on to the track sensor by transfer of these data words to the fire control computer 18 .

The reduction in the fourth evaluation process by reducing the resolution makes the amount of data obtained much faster and easier to handle, whereby the knowledge is used that a high-resolution sensor system is advantageous for the early detection of the missile flying at a great distance, but it does Surprisingly, it is not necessary to carry out the evaluation of the detected object as to whether it corresponds to the missile to be combated with the high resolution with which the missile is detected. It is essential for the success of the anti-aircraft device according to the invention that this evaluation is carried out quickly and correctly. Due to the data reduction shown in FIG. 4, the resolution of the captured image being reduced, the objects can be evaluated with the necessary speed and with the necessary security. The functionality of the device according to the invention could be demonstrated in practical tests to ward off approaching missiles.

Furthermore, the track sensor, which only works in the close range, the directional data with this low resolution or precision transmitted. Because this directional data or directional information are given in angular ranges, the size of the by the angular ranges indirectly defined surface segments tional to the distance, so that also by the relatively "uneven nauen "(+/- 10 ′) angular ranges in the vicinity of the missile sufficiently precise descriptive area segment defined is.

The parallel reduction of the data and the subsequent merging of the reduced amount of data allows the object data to be obtained from the control computer 6 within one to three seconds. This means that a large, passively recorded amount of data can be evaluated and used to control the track sensor 8 within a very short time.

A missile that flies to one of the two cameras 2 , 4 on a camera axis cannot be perceived by this camera, or can only be perceived very late, because its signature hardly changes in the detected image. The provision of the two cameras 2 , 4 creates a redundant system, so that reliable detection is possible with at least one of the two cameras 2 , 4 even when a missile is flying directly towards a camera. The two cameras 2 , 4 are therefore not used to generate a stereo image, but are each evaluated separately, with a comparison and a corresponding correction being carried out when the two video signals processed in parallel are combined.

The fact that a digitally recorded, huge amount of data in can be reduced to the little data in the shortest possible time it is possible to quickly determine the direction of the missile and this with the necessary speed, security and ge forward accuracy to the track sensor.

With the aid of the object data, the optical track sensor 8 is “placed” on the direction of the missile. The missile is also tracked with the aid of digital image processing of the camera image obtained with the track sensor. The azimuth angle and the elevation angle of the missile are determined by means of the two angle sensors. The distance of the missile is continuously measured with the laser range finder. The approach direction of the missile is calculated in real time from the data obtained in this way, whereupon the control computer 6 outputs signals via lines 11 , 13 for actuating the drives 12, 14 of the track sensor 8 and thus for tracking this track sensor. Furthermore, 6 signals are passed to the fire control computer 18 via the output line 16 of the control computer, which in turn generates tracking signals for the lines 26 , 30 to the drives 24 , 28 for the platform via the control unit 19 . The fire control computer 18 uses the track sensor 8 and the weapon and system-specific data to calculate the reserve of the barrel weapon 20 , tracks the barrel weapon 20 and triggers a shot or a short sequence of shots when the specified combat range is reached.

The optical sensor system can also be formed from cameras 2 , 4 , with large-area sensors of, for example, 4,096 × 4,096 pixels, which are preferably freely addressable (random access). In such freely addressable areas, certain areas on the sensor can be selected separately by the evaluation device and read out separately.

Cameras with these large-area, freely addressable sensors can be used not only to record the missiles, but also simultaneously as track sensors, with a sensor subarea being selected based on the above-described, reduced data ( FIG. 4) by means of guided evaluation of the approaching missiles with which the approaching missile is detected. This limited sensor partial area then serves as a track sensor, which does not have to be adjusted mechanically, but can be tracked by moving the sensor partial area on the sensor to the approaching missile. By evaluating a sub-area of the sensor, there are no large amounts of data during "tracking", which, like the track sensor known per se, are preferably evaluated by separate evaluation electronics. Two or three units of such evaluation electronics can also be connected to a sensor for "tracking", so that several can be tracked or "tracked" to flying missiles at the same time.

If a sensor sub-area takes over the function of the track sensor, this reduces the mechanical, hydraulic and electronic control effort essential. In addition, there is no time span ne that a track sensor needs to approach on an approaching  Swing in the missile.

The image sensors can be optical (VISible), ultraviolet (UV), near and far infrared (IR) sensitive sensors ver be applied. The sensors can be used as CCD (charge coupled devi ce), CID (charge injection device), IICCD (image intensified CCD), IICID (image intensified CID), HDRC (high dynamic range CMOS) or as a bipolar BPDA (photodiode array) be.

The sensor is preferably a so-called smart optical sensor trained, d. that is, simple "intelligent" Components are integrated, for example a first data make reduction. This can accelerate both the evaluation as well as a simplification of the structure will.

In the illustration according to FIG. 3, a horizontal axis s is shown, on which arrows labeled in ascending order with increasing Roman numerals indicate striking distances to a zero point at arrow V in the location of a device according to the invention. The distance between the arrow I and the zero point V is 2000 meters, between the arrow II and the zero point 900 to 700 meters and between the arrow IV and the zero point V 500 to 300 meters.

The approaching missile designated by the reference number 40 in FIG. 3 is roughly detected when the arrow II is flown over, that is to say at a distance of 900 to 700 meters from the zero point V. This is possible with the passively working device according to the invention, which can detect objects of approximately 10 cm in diameter, larger approaching missiles from a distance of approximately 900 meters, however, accordingly earlier. The track sensor 8 then touches the determined flight path of the missile, and the platform 22 of the barrel weapon 20 is tracked in accordance with the movement of the platform 10 of the track sensor 8 . This tracking process is completed when the missile 40 flies over location IV. Then the shot is released.

For larger targets, such as airplanes or helicopters, the rough target acquisition takes place much earlier, as I said. In this case, the approaching missile can also be combated with a missile instead of a cannon, which can be launched, for example, when the missile 40 is flown at position I (2000 m distance from the zero point V). A starter housing for such a rocket is designated by the reference number 42 in FIG. 1.

Claims (28)

1. A method for combating incoming missiles, in which missiles ( 40 ) are detected by means of a sensor system with a large field of view, the captured image data are processed by a computer ( 6 , 18 ), and the missile ( 40 ) with a weapon in accordance with the combat captured image data, characterized in that the missile ( 40 ) is passively captured by the sensor system ( 2 , 4 ) with a high resolution and the resolution of the captured image data for an assessment of whether or not the missile should be combated, is reduced so that the amount of data for the evaluation process is reduced. 2. The method according to claim 1, characterized in that the processed image data are passed on to an optical track sensor that follows the missile ( 40 ) ver, so that the weapon on the missile ( 40 ) can be targeted and combated. 3. The method according to claim 2, characterized in that the directional information about the missile, which are passed on to the track sensor by an elevation and azimuth angle range, which is not larger than the visual range of the track sensor ( 8 ). 4. The method according to claim 1, characterized in that the sensor system has at least one large-area sensor, with a first evaluation unit and a two-th evaluation unit, which, after the approaching missile has been evaluated as relevant for combat, a sensor sub-area selects and evaluates in which the missile is depicted and the sensor sub-area corresponding to the movement of the missile ( 40 ). 5. The method according to one or more of claims 1 to 4, characterized in that the sensor system has two cameras ( 2 , 4 ) whose video signals are digitized in parallel. 6. The method according to one or more of claims 1 to 5, characterized in that image data acquired with the sensor system ( 2 , 4 ) represent images subdivided into pixels P _xy , a gray level being assigned to each pixel. 7. The method according to claim 6, characterized in that mean values of the gray levels of the pixels P _xy of successive images are determined. 8. The method according to claim 7, characterized in that the mean values of the gray _{levels of} the individual pixels are calculated according to the following formula P _{xyref, i} = P _{xyref, i-1} · Gew + P _xyakt (1-Gew), which is applied recursively, wherein an average value P _{xyref, i of} a gray level of a pixel P _{xy is determined} from a previous average value P _{xyref, i-1} and the currently measured gray level P _xyakt , where Gew is a weighting factor that has, for example, a value of 0.9 and preferably is in the range of 0.7 to 0.95. 9. The method according to claim 8, characterized in that a difference image is determined in which the difference between P _{xyref of} the mean value image with the pixels P _{xyakt of} the current image is calculated according to the following formula: P _xyDiff = P _xyref - P _xyakt . 10. The method according to claim 9, characterized, that the value of the pixels is reduced to a bit object signal that only contains the information whether the Verify the value of the pixel in the successive images has changed. 11. The method according to one or more of claims 1 to 10, characterized in that the resolution of the image data is reduced by combining a plurality of pixels P _xy to form a segment S, each segment S being assigned a single bit, which represents a reduced pixel that is set when a single pixel contained in segment S is set. 12. The method according to claim 11, characterized, that a segment S comprises at least 4 × 4 pixels. 13. The method according to claim 11 and / or 12, characterized, that a signature of a detected missile by size, Shape and movement in the picture is assessed whether the on flying missile is relevant, d. i.e. whether he is fighting shall be. 14. The method according to one or more of claims 5 to 13, characterized,  that the data processed in parallel are merged the, with the object signals each in a data word be summarized, the respective camera number, Zei contains leninformation and column information. 15. The method according to one or more of claims 1 to 3 or 5 to 14, characterized in that

• - The rough approach direction of the missile ( 40 ) is determined from the image data acquired with the sensor system ( 2 , 4 ),
• - The optical track sensor ( 8 ) is placed on the flight direction determined in this way,
• - The angular position of the missile in azimuth and elevation of two angle encoders and the distance of the missile pers is detected by a range finder, from the data output by the track sensor ( 8 ), the range finder and the angle encoders, the space coordinates of the missile are calculated in real time will,
• - The calculated space coordinates of the missile are entered into a fire control computer ( 18 ),
• - The fire control computer ( 18 ) controls the weapon to track and combat the missile ( 40 ).

16. A device for combating approaching missiles, in particular for carrying out the method according to one or more of claims 1 to 15, with

• a sensor system with a large field of vision for detecting a missile ( 40 ),
• - a computer ( 6 ) for processing the captured image data,
• a weapon ( 20 ) for combating the missile ( 40 ) in accordance with the captured image data,

characterized in that the sensor system ( 2 , 4 ) has passive sensors. 17. The apparatus according to claim 16, characterized in that a track sensor ( 8 ) for detecting the missile ( 40 ) is provided in the vicinity and the track sensor ( 8 ) together with a range finder and angle sensors on one perpendicular to each other Axis pivotable platform ( 10 ) is arranged. 18. The apparatus according to claim 16 and / or 17, characterized in that the computer ( 6 ), a control computer ( 6 ) for processing the output data of the sensor system ( 2 , 4 ) and for driving the platform ( 10 ) of the track sensor ( 8 ) and a fire control computer ( 18 ). 19. The device according to one or more of claims 16 to 18, characterized in that the sensors ( 2 , 4 ) of the sensor system are cameras with a large field of view. 20. The device according to one or more of claims 16 to 19, characterized in that the sensors ( 2 , 4 ) of the sensor system each consist of a camera block with, for example, four camera modules, each camera module being formed from a camera with a large field of view. 21. The apparatus of claim 19 or 20, characterized, that the cameras with large field of view CCD cameras or HDRC cameras are. 22. The apparatus of claim 19 or 21, characterized, that the cameras with a large field of view are TV cameras.   23. The device according to claim 19 or 22, characterized, that the cameras with a large field of view are infrared cameras. 24. The device according to one or more of claims 16 to 23, characterized in that the weapon is a tubular weapon ( 20 ) which is arranged on a special, pivotable platform ( 22 ) which with two separate angle encoders for azimuth and Eleva tion angle is equipped and from a fire control computer ( 18 ) downstream control unit ( 19 ) is trackable. 25. The device according to claim 24, characterized in that the barrel weapon ( 20 ) is rigidly attached to the platform ( 22 ) and that the platform is pivotable in azimuth and elevation. 26. The device according to one or more of claims 16 to 23, characterized in that the weapon is a barrel weapon ( 20 ) which is arranged together with the track sensor ( 8 ) on a platform ( 10 ), the track sensor ( 8 ) can be set independently of the barrel weapon ( 20 ) on the platform ( 10 ). 27. The device according to one or more of claims 16 to 23, characterized, that the weapon has anti-missiles.