Abstract:
A method steers a missile towards a flying target. In order to permit precise flight to the target even under poor visibility conditions owing to the weather, a radar which is remote from the missile detects the target and transmits data relating to a first location area of the target to the missile. The missile determines, from the data of its own missile radar, a second location area of the target, processes both location areas to form a target area and flies to the target area.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the priority, under 35 U.S.C. §119, of German application DE 10 2016 003 238.3, filed Mar. 16, 2016; the prior application is herewith incorporated by reference in its entirety. 
       BACKGROUND OF THE INVENTION 
       [0002]    Field of the Invention 
         [0003]    The invention relates to a method for steering a missile towards a flying target. 
         [0004]    In ground-based air defence, a flying target is detected by ground radar and a location area of the target in the air space is determined from the radar data. Data relating to this location area is transmitted to an air defence missile which heads for the target on the basis of this data. However, with such external alignment by data link there is the problem that the target data which is transmitted for the purpose of alignment contains errors and is at risk of dropping out, and in addition reaches the missile only with a delay. The status variables of the target which are estimated by the guidance of the missile correspondingly contain errors. Therefore, only an imprecise approach flight is possible. 
         [0005]    In order to achieve a precise final approach, modern medium-range aerial target engagement systems comprise, for example, an image-resolving infrared homing system with which the target which is being approached by air is detected as an image. On the basis of the image data, the missile can determine a location area of the target with high precision, flies towards the target and effectively engage with it. 
       SUMMARY OF THE INVENTION 
       [0006]    An object of the present invention is to specify an improved method for steering a missile towards a flying target. 
         [0007]    This object is achieved by a method of the type mentioned at the beginning, in which according to the invention a radar which is remote from the missile detects the target and transmits data relating to a first location area of the target to the missile, the missile determines, from the data of its own missile radar, a second location area of the target, processes both location areas to form a target area and flies to the target area. 
         [0008]    The invention is based on the idea that the missile is steered to the first location area of the target exclusively on the basis of the data of the remote radar, until a possibly present close-range homing device locks onto the target. Although a predicted impact point (PIP) is calculated from the first location area to which the missile is directed, this impact point (PIP) can be relatively remote from the actual target or impact point owing to an alignment error. Without a close-range homing device, the missile flies past the target by a large distance. If a close-range homing device is present, when it locks onto the target the alignment error becomes visible and can be compensated. After the locking on, a necessary condition for a hit is that the alignment error must be completely eliminated in the remaining flight time of the missile to the target. Here, the detection range of, for example, passive infrared homing devices given clear visibility is a multiple of the minimum detection range predefined by the necessary condition for a hit. Under favorable weather conditions, the missile therefore has a generous steering margin, also to cope with unexpected manoeuvres of the target. The detection range can, however, be limited by influences due to the weather. If the target is locked onto only below the minimum detection range for the close-range homing device owing to meteorological conditions, a hit is no longer guaranteed. 
         [0009]    In order to solve this problem, the missile is equipped with a missile radar which, even when there is no optical contact with the target, can already detect the target or determines data relating to the target. In this context it is sufficient if, for example, only distance data is determined. Although the data which is determined by the missile radar is, under certain circumstances, not sufficient for independent alignment, since, for example, a direction indication is missing, the data can be processed together with the data of the first location area of the target, determined by the remote radar, to form a sufficiently precise target area. If, for example, the first location area of the target which is determined by the remote radar is too large to permit precise steering of the missile in the end phase of the approach flight, linking of the location probabilities of the target in the first and second location areas can give rise to a smaller target area which is within the minimum detection range. Even if the target is in a cloud and also cannot be detected optically until engagement, the target range can be so small that engagement is possible entirely without optical contact. 
         [0010]    The missile is expediently a missile for ground-supported air defence with a rocket motor and, in particular, with a homing head with a homing system for two-dimensional angled detection of the target in the azimuth direction and elevation direction with respect to the axis of the missile. The system which is referred to below as an image-processing homing system or close-range homing device can be a passive infrared homing system with a detector which is sensitive in the infrared spectral range and with which images of the surroundings are detected. Likewise, an active radar homing device is possible with which direction-resolved detection of targets is made possible, also only in the final phase of the approach flight owing to the required energy supply. 
         [0011]    The radar which is remote from the missile can be a ground radar or a radar of an aircraft. The missile radar expediently contains a radar sensor which is immobile relative to an external housing of the missile. As a result, the radar sensor technology can be kept particularly simple and cost-effective. This data of the radar sensor can be evaluated by a control unit of the missile, wherein for reasons of saving costs, installation space and weight, expediently only distance data are determined from the data of the radar sensor. 
         [0012]    The location areas must be strictly delimited areas in the airspace. A location area can be a probability distribution in space with or without limitation, e.g. a distribution of the location probability of the target in space. The same applies to the target area. If a spatial limitation of the location areas or of the target area occurs, this can occur, for example, as a result of the combination of all those areas in which the location probability is above a predetermined limiting value. 
         [0013]    The processing of the two location areas to form a target area can be achieved by fusing the data of the two location areas by means of a common entry in a state filter. The processing of the two location areas to form a target area occurs immediately when location probability data of the remote radar and of the missile radar are processed to form the target area. This can be done by data fusion, for example by inputting the data of the missile radar and of the remote radar into a state estimator, for example a Kalman filter. The data relating to the location areas advantageously contains a two-dimensional or three-dimensional function of the location probability of the target as a function of the position. Dividing the location areas respectively into a multiplicity of sub-areas with various location probabilities can also be understood to be such a function. The position-dependent location probability is expediently determined by a state filter, for example a Kalman filter. 
         [0014]    In one advantageous embodiment of the invention, position-resolved location probabilities of the target in the two location areas are combined in the missile to form a superordinate, position-resolved location probability. The target area can be determined from this superordinate position-resolved location probability of the target. The combination can be carried out by multiplying the probabilities. 
         [0015]    In a further embodiment of the invention, the missile radar measures the distance from the target, and the missile, expediently a control unit of the missile, determines a probability of the target being located in the second location area from the data of the distance measurement. The position-resolved location probability of the first location area can be linked by the missile to the location probability resulting from the distance measurement. As a result, a small target area can be determined for precise steering of the missile in the direction of the target. 
         [0016]    Depending on the position of the remote radar with respect to the direction of flight of the missile it may be the case that the two location areas are located with respect to one another in such a way that their intersection areas result in a target area which is unfavorably large or is unfavourably distributed in space. It therefore may be the case, for example, that the target area contains sub-areas in which the target can be located which are at a distance from one another in space. Depending on the selection of the sub-area by the missile, in this context the target can be missed. In order to avoid this, it is advantageous if the missile has at least three forward-oriented radar sensors. The radar sensors are expediently oriented in different spatial directions, with respect to the axis of the missile. The radar sensors expediently each monitor just one spatial segment of at least three spatial segments lying one next to the other. The spatial segments can adjoin one another or partially overlap one another. As a result of the different orientation of the radar sensors in space, a rough determination of the direction can be derived from the signals of the sensors. This determination may be sufficient to clarify a target area ambivalence and to avoid an incorrect selection of the sub-area. In order to determine the correct sub-area, the segment probabilities, that is to say location probability of the target in the respective segment of the radar sensor, can be processed together with location probabilities in the two location areas. 
         [0017]    If the target flies in a cloud when it is approached by the missile, it may be the case that the missile cannot detect the target by a homing system until engagement. A position-resolved optical image, for example in the infrared spectral range, cannot be used to steer the missile. However, the distance of the missile from the target is known from the data of the missile radar. If the missile flies past the target, the measured distance increases again, with the result that a position of maximum approach can be estimated from the development of the distance data. In the vicinity of this position, an active body of the missile can be fired, and the target can be engaged with even without optical contact. In this regard it is advantageous if the missile radar is used as a proximity sensor for the firing of a charge of the missile. 
         [0018]    In the presence of a plurality of radar sensors which are oriented in different directions, it is additionally possible to determine a direction or example a directional area in which the target lies, as it flies past, relative to the axis of the missile. Engagement effectiveness can be increased if the charge is fired in a direction-dependent fashion, wherein directional data of the missile radar, for example a segment number in which the target is located, are used during the determination of the firing direction. The charge can be concentrated in a directional area, as a result of which an effective engagement radius is increased. In this respect, the spatial segment in which the target is located is expediently determined as the missile flies past the target, and firing of the explosive charge is controlled at least largely into this spatial segment. The term largely can be understood here to mean more than 50% of the total effective force. The spatial segment extends expediently in an azimuth angle range of less than 180°, in particular less than 140°, about the axis of the missile. 
         [0019]    The approach flight of the missile can be divided into a plurality of phases in which directional control of the flight of the missile is dependent on data from various data sources. In an alignment phase, the flight control occurs only, or predominantly, by data of the remote radar. It is possible to dispense with the use of the data of the missile radar, insofar as it is already available. In a middle phase following the alignment phase, the directional control of the flight of the missile expediently takes place only, or predominantly, by linking the data of the remote radar and that of the missile radar. The alignment and middle phase can be delimited from one another by the time at which the missile radar detects the target or recognizes it as such and has determined the distance from the target. In a third optional final phase, the directional control of the flight of the missile can take place only, or predominantly, by linking the data of the missile radar and of an image-resolving homing system of the missile, in particular of an infrared homing system of the missile. In principle, the directional control in the end phase can also take place solely by the internal homing system, but support by means of the data of the missile radar is advantageous, in particular for controlling the steering deflection, that is to say the flight agility. The middle phase and end phase can be delimited from one another by the time at which the missile-internal homing system recognizes the target as such and has determined the direction of the target relative to an axis of the missile. 
         [0020]    If the missile is in this respect expediently equipped with an image-resolving infrared homing system with the data of which the missile is controlled at least in an end phase of the approach flight to the target. A precise approach flight can be achieved under initially poor visibility conditions if the missile flies at least largely under radar control to the target area before the target can be sighted optically in the IR homing system, and after optical detection of the target by the IR homing system flies at least largely under optical control towards the target. The radar control expediently takes place using the data of the target generated by the missile radar. Predominant approaching of the target with one or other system can take place in that the radar data or optical data is evaluated more highly in a state estimation than the data of the corresponding other system. 
         [0021]    Before two-dimensional detection of the target by a homing system, the homing system will search for the target in a spatial area and expediently scan the spatial area. Such a search can be simplified or sped up if the position of the second location area of the target which is determined by the missile radar is used to control a viewing direction of the homing system relative to the missile axis. The position of the first location area is expediently also used for this, or the position of the target area, for example relative to the missile axis. Before the target becomes visible to the homing system, the orientation of the homing system can be controlled into the target area, wherein the orientation of the homing system can be held in the target area during the approach flight and before the optical target detection. 
         [0022]    If the target has been detected in a two-dimensional fashion by the homing system and if the missile flies towards the target on the basis of the data generated by the homing system, it is advantageous to know the distance from the target and to take this into account in the control of the flight. In this respect it is advantageous if the distance and/or approach speed of the missile to the target, which are determined by the missile radar, are used as parameters for controlling the flight. If the missile is, for example, steered towards the target by proportional navigation, the line of sight spin rate can be used as steering parameter. The spin rate can be adjusted to zero, in order to remain on a collision course with the target. Surface deflection is dependent here on the line of sight spin rate of the target and expediently on the distance and/or approach speed of the missile to the target. 
         [0023]    The invention is also directed to a missile which according to the invention is equipped with a distance radar, an IR homing system with two-dimensional resolution, control surfaces for controlling a steered flight, and a control unit which is prepared for generating steering signals from the data of the distance radar and of the IR homing system and for actuating the control surfaces with said signals. When the IR homing system does not have sight of the target, the missile can firstly be steered to the target by using the data from the distance radar. Steering to the target can also be carried out precisely even under unfavourable weather conditions. 
         [0024]    If the target is still outside the range of the distance radar, it is advantageous if the control unit is prepared to process data from a remotely arranged radar, for example a ground radar. A first location area which is determined by the ground radar can be linked to, by a second location area determined by the distance radar, to a target area towards which the missile is steered. 
         [0025]    The distance radar is advantageously equipped with at least three forward-oriented radar sensors. The scanning range of the radar sensors expediently lies in each case in just one spatial segment of at least three spatial segments lying one next to the other. 
         [0026]    A favorable arrangement of a plurality of radar sensors can be achieved if they are arranged in the region of a transition cone between a missile head and a missile body. The radar sensors are expediently fixedly attached to an external housing of the missile, with the result that their viewing direction is oriented immovably with respect to the axis of the missile. 
         [0027]    The previously provided description of advantageous refinements of the invention contains numerous features, a plurality of which are represented combined in a number of dependent claims. However, these features can also be expediently considered individually and combined to form appropriate further combinations, in particular with back references of claims, with the result that a single feature of a dependent claim can be combined with a single feature or a plurality of features or all the features of another dependent claim. Furthermore, these features can each be combined individually and in any suitable combination both with the inventive method and with the inventive device according to the independent claims. Therefore, method features can also be considered to be formulated in physical terms as properties of the corresponding device unit and functional device features can also be formulated as corresponding method features. 
         [0028]    The properties, features and advantages of this invention which are described above as well as the way in which they are achieved become clearer and more clearly comprehensible in conjunction with the following description of the exemplary embodiments which are explained in more detail in conjunction with the drawings. The exemplary embodiments serve to explain the invention and do not limit the invention to the combination of features specified therein, and not in relation to functional features either. Furthermore, features of each exemplary embodiment which are suitable for this can also be considered explicitly in isolation, removed from an exemplary embodiment, introduced into another exemplary embodiment to supplement it and/or combined with any of the claims. 
         [0029]    Other features which are considered as characteristic for the invention are set forth in the appended claims. 
         [0030]    Although the invention is illustrated and described herein as embodied in a method for steering a missile towards a flying target, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
         [0031]    The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
         [0032]      FIG. 1  is a diagrammatic, perspective view of a missile in the form of a guided missile with a homing head, an effective part and a rocket engine, according to the invention; 
           [0033]      FIG. 2  is an illustration showing the flying missile which is aligned by a ground radar with a target concealed by a cloud; 
           [0034]      FIG. 3  is an illustration showing the missile in an approach flight to the target whose position is estimated from two location areas; and 
           [0035]      FIG. 4  is a perspective view of the missile as it flies past the target during the triggering of an charge of the effective part, oriented towards the target. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0036]    Referring now to the figures of the drawings in detail and first, particularly to  FIG. 1  thereof, there is shown a missile  2  in the form of a guided missile for ground-based air defence. The missile  2  is equipped with a rocket motor  4 , an effective part  6  which contains an explosive charge, and a homing head  8  which has an IR homing system  10  for detecting a target which is luminous in the infrared spectral range, with two-dimensional resolution in the front spatial area in front of the missile  2 . In order to steer the missile  2  towards the target, the missile  2  contains control surfaces  12  on control vanes  14  which are arranged in the rear of the missile  2  and are actuated by a control unit  16 . A missile radar  20  is arranged in a transition area  18  between the homing head  8  and the body part which is embodied in a thicker fashion radially with respect thereto and lies behind the homing head  8 . This system which is arranged in the conical transition area  18  contains four radar sensors  22  which each detect a spatial segment  24  by a sensor. The spatial segments  24  are indicated by dashed lines in  FIG. 1  and each have an azimuthal extent of 90° and are arranged adjoining one another, adjacently symmetrical about the longitudinal axis of the missile  2  or axis of the missile. Their elevation angle is from 110° relative to the axis of the missile up to −3° in the forward direction, with the result that the spatial segments  24  overlap by approximately 6° in the forward direction. 
         [0037]      FIG. 2  shows a flying target  26  (indicated only by a cross) for example a rocket which has an explosive head and is to be engaged with by the missile  2 . For this purpose, the target  26  is detected as such by a radar  28  which is remote from the missile  2 . The radar  28  is a ground radar  28  in this exemplary embodiment but can also be an air-based radar of an aircraft. The target is detected by the ground radar  28  and classified as an object to be engaged with. For the purpose of engagement, the missile  2  is started from a platform which can be a ground-based platform or a flying platform. After the target  26  has been detected by the ground radar  28 , alignment data are sent to the missile  2  from the ground radar  28 . The data contains information relating to a first location area  30  within which the ground radar  28  has made out the target  26 . The detection of the target  26  by the ground radar  28  is extremely precise in terms of the distance from the ground radar  28  to the target  26 , but the determination of angles by the ground radar  28  takes place significantly less precisely. The location area  30  therefore has the shape of a pressed-flat rotational ellipsoid, which is illustrated in simplified form in  FIG. 2  by an ellipse. The extent of the rotational ellipsoid is significantly larger perpendicularly with respect to the direction of the ground radar  28  than in the direction of the ground radar  28 . 
         [0038]    The steering of the missile  2  towards the target  26  takes place in three chronologically successive phases. In the first alignment phase, target coordinates of the target  26  are generated exclusively from the alignment data of the ground radar  28 . Expressed in simplified terms, the flight of the missile  2  is controlled exclusively on the basis of the alignment data of the ground radar  28 . In the subsequent middle phase, alignment data of the ground radar  28  are fused with data of the missile radar  20 . In this middle phase or radar fusion phase, the flight of the missile  2  is controlled on the basis of fusion data which are acquired from the processing of the data of the ground radar  28  and of the missile radar  20 . In the third and last phase, the final phase, the flight control is performed at least largely on the basis of the data of the IR homing system  10  of the missile  2 . It is possible to dispense with the use of the alignment data of the ground radar  28 , and the radar data of the missile radar  20  is used merely to assist, for example for the distance measurement for controlling the agility. The determination of direction to the target expediently takes place exclusively by means of the missile&#39;s own homing system  10 . 
         [0039]    In the exemplary embodiment illustrated in  FIG. 2 , the sight of the missile  2  of the target  26  is blocked by a cloud  32 . In the first alignment phase, the missile  2  firstly flies exclusively with alignment data of the ground radar  28  in the direction of the location area  30 . The location of the target  26  within the location area  30  is still unclear. Therefore, the missile  2  aims for a preliminary target point  34  which, expressed in simple terms, can lie at the geometric center point of the location area  30 . In  FIG. 2 , this flight route is indicated by a line of narrow dashes. 
         [0040]    If the missile  2  were to fly through the cloud  32  on this flight route, the missile  2  would acquire sight of the actual target  26  just before the theoretical target point  34 . The optical distance  36  to the target  26  is relatively short in this case and is indicated by a dot-dashed line. Although the infrared homing system  10  would detect the target  26 , and the missile  2  would attempt to swerve in towards the target  26  on the basis of the data of the homing system  10 , as a result of the short optical distance  36  which is below a minimum lock-on range, that is to say a minimum distance at which the target must be picked up optically in order to achieve a high hit rate, the hit rate or probability of a hit will be very low. The missile  2  will fly past the target  26 . 
         [0041]    In order to avoid such incorrect control, the missile  2  is equipped with a missile radar  20 . During the alignment phase, the missile radar  20  actively emits radiation and finally detects the target  26 . The detection takes place exclusively by means of distance detection, with the result that the distance r of the missile  2  from the target  26  is determined. On the basis of this distance r, a second location area  38 , in which there is a high probability of the target  26  being located solely on the basis of the data of the missile radar  20 , is obtained. The location area  38  is in the shape of a spherical cup, the radial thickness of which depends on the distance-measuring accuracy of the missile radar  20 . In order to simplify the illustration, this location area  38  is illustrated in  FIG. 2  by a dotted circular section. 
         [0042]    From the comparison of the two location areas  30 ,  38  it becomes clear that the probability of the target  26  being located at the theoretical target point  34  which is determined on the basis of the data of the ground radar  28  is set low. This is because this target point  38  lies significantly further away than the distance measurement of the missile radar  20  has indicated. Therefore, the data of the ground radar  28  is combined with the data of the missile radar  20  and processed to form a target area  40 . This can be done by transferring the data of the two radars  20 ,  28  to an algorithm for estimating the location probability of the target  26 , for example to a Kalman filter as input data and by calculating the location probability of the target  26  therefrom. In this respect, the position-resolved probabilities of the target  26  being located in the two location areas  30 ,  38  are combined in the missile  2  to form a superordinate, position-resolved location probability of the target area  40 . In particular, the position-resolved probability of the target  26  being located in the first location area  30 , which probability is supplied by the ground radar  28 , is linked to the location probability of the target  26  in the second location area  38 , which results from the distance measurement. 
         [0043]    The location areas  30 ,  38  can be bounded or unbounded entities and each contain a location probability distribution of the target  26  in space. The conceptualization of the areas  30 ,  38 ,  40  is merely for the sake of better illustration. An area can be a spatial entity in which the location probability of the target  26  in the space is above a limiting value. This entity can be but does not have to be specifically formed in the missile  2 . 
         [0044]    At the start of the middle phase or radar fusion phase, the flight of the missile  2  is therefore corrected, with the result that it flies towards the target area  40 . This is illustrated in  FIG. 2  by the line of long dashes. The precise target point which is aimed at within the target area  40  can be the geometric center point or some other point with a larger location probability, for example with the maximum location probability corresponding to the current state estimation. 
         [0045]    During the middle phase, the missile  2  flies towards the target area  40  in a manner controlled by the data which have been fused by the two radars  20 ,  28 . In the illustration in  FIG. 2 , the missile  2  leaves the cloud  32  just before reaching the target area  40  and obtains unimpeded sight of the target  26 . The optical distance  42  or the target concealment distance from which the target  26  becomes optically visible to the missile&#39;s own homing system  10  is also very short here, and not significantly longer than the optical distance  36 . However, the flight direction correction which is to be performed is significantly smaller, with the result that the minimum lock-on range is shorter than before. The optical distance  42  is longer than the minimum lock-on range, and the missile  2  can, during its flight, swerve in towards the target  26  and directly hit it. 
         [0046]    During the middle phase, the missile-internal homing system  10  does not yet lock on to the target  26 , and the target  26  has therefore not yet been detected by the homing system  10 . However, the approximate position of the target  26  in the target area  40  is known. This position and/or the extent of the target area  40  are used to control the orientation of the homing system  10 . Therefore, a search space of the homing system  10 , which is scanned by it, can be limited, for example, to the target area  40  or to some other area which is determined as a function of the geometry of the target area  40 , for example which extends beyond the target area  40  in a predefined fashion. 
         [0047]    During the final phase, the data of the internal homing system  10  is used for the direction control of the missile  2 , with the result that after the homing system  10  has locked on to the target  26  the final phase of the target approach flight begins. In this final phase, the data of the missile-internal homing system  10  is used to steer the missile  2  to the destination  26 . The distance from the destination and/or the approach speed of the missile  2  to the target  26  which are determined by the missile radar  20  can be used as an additional parameter of the flight control. 
         [0048]      FIG. 3  shows a further exemplary embodiment of a location area  30  which has been determined from data of a remotely arranged radar and of a location area  38  which has been determined from data of the missile radar  20  of the missile  2 . The following description is limited essentially to the differences with respect to the exemplary embodiment from  FIG. 2 , to which reference is made in relation to features and functions which remain the same. In order to avoid having to repeat what has already been described, all the features of a preceding exemplary embodiment are generally adopted in the respective following exemplary embodiment, without being described again, unless features are described as differences with respect to one or more preceding exemplary embodiments. 
         [0049]    In order to simplify the illustration, the location area  30  in  FIG. 3  is illustrated in turn as an ellipse, and the location area  38  as a circular arc-shaped segment. It is apparent that the location area  38  penetrates or intersects the location area  30  in a plurality of target areas  44 . In the illustration in  FIG. 3 , this is illustrated in the form that the location area  38  is concealed in the inner area between the two target areas  44  by the location area  30 . This is shown by a dotted illustration of the location area  38 . However, in the outer area of the location area  30  the location area  38  lies in front of the location area  30 , which is illustrated by continuous lines. The arrangement in front of or behind can be understood in terms of the view of the missile  2 . 
         [0050]    Given a theoretically virtual spherical cap shape of the location area  38  and a circular face of the location area  30 , the target areas  44  are combined in a circular shape in a target area. Depending on the radial thickness of the two location areas  30 ,  38 , this target area  44  is geometrically more complex, wherein the complexity increases further as a result of the different probabilities of location at the center or in the peripheral areas of the location areas  30 ,  38 . The illustration from  FIG. 3  is therefore to be understood only as a schematic illustration which makes it clear that data fusion of data of the missile radar  20  and of the ground radar  28  can also give rise to a large and complex target area  44 . An extremely accurate approach of the target  26  can be impeded by this. 
         [0051]    In order nevertheless to achieve a precise approach flight to the target, the missile radar  20  is equipped with the multiplicity of radar sensors  22 . In the illustration in  FIG. 3 , it is clear that the lower target area  44  would be detected by the lower radar sensor  22 —if that is where the target  26  were located—and the upper target area  44  would be detected by the upper radar sensor  22 . However, since target detection occurs only by one of the radar sensors  22 , it is clear which spatial segment  24  the target  26  is located in. Even if the spatial segments  24  overlap, the location of the target  26  can be determined unambiguously since the overlapping areas of the spatial segments  24  are expediently considerably smaller than the spatial segments  24  themselves. In this respect, the spatial segment  24  is determined having the highest probability of the target  26  being located in this spatial segment  24 , this is abbreviated as the segment probability. This segment probability is used during the determination of the position-resolved probability of the target  26  being located in the target area  40 . 
         [0052]    In the exemplary embodiment shown in  FIG. 3 , the target  26  lies in the upper target area  44 , with the result that on the basis of the data of the missile radar  20  the target area  44  can be limited to the upper target area  44 . The missile  2  can then be steered to this target area  44  in the middle phase. When the cloud  32  is exited, the optical distance  42  or the target concealment distance from the missile  2  to the target  26  is shorter than the minimum lock-on range  46 , with the result that the target  26  can be hit. Therefore, after the detection of the target  26  by the missile-internal homing system  26  in the transition from the middle phase into the final phase, the missile  2  swerves in from the theoretical target point  48  of the target area  44  onto the actual target  26  and then flies specifically towards the target  26 . 
         [0053]    In the exemplary embodiments shown in  FIGS. 2 and 3 , a movement of the target  26  itself is not taken into account. However, this is not critical since both the ground radar  28  and the missile radar  20  continuously supply target data, with the result that the location areas  30 ,  38  or the target area  40 ,  44  can always be calculated in an updated fashion, for example by state estimation. In accordance with this calculation or data fusion, the target  26  is continuously tracked in its movement by the missile  2 . 
         [0054]    Given particularly poor visibility conditions, it may be the case that the steering towards the target  26  has to take place without a final phase, since the on-board homing system  10  cannot detect the target  26  because of poor visibility. If the target  26  is located, for example, in a cloud, the sight of the target  26  may be permanently blocked. A target approach flight can then take place without the involvement of the infrared homing system  10 . 
         [0055]      FIG. 4  shows such an exemplary embodiment in which the missile  2  flies towards the target  26  without optical sight. The approach flight is, of course, not as precise as when the homing system  10  is used, with the result that a flypast takes place, as illustrated in  FIG. 4 . The missile  2  flies past the target  26  at a very short distance  50 . From the detection of the target  26  by one of the radar sensors  22  it is clear which spatial segment  24  the target  26  is located in. In the exemplary embodiment illustrated in  FIG. 4 , the target  26  is located in the spatial segment  24  (illustrated above) of the radar sensor  22  which is oriented upwards in  FIG. 4 . In this respect, the current distance of the missile  2  from the target  26 , and the spatial segment  24  in which the target  26  is located relative to the axis of the missile  2 , are always known. The distance from the target is then constantly monitored. The distance decreases continuously and reaches its minimum at the moment of the flypast. At the moment when the distance increases again, it is clear that the missile  2  has flown past the target  26 . If the minimum distance  50  of the missile  2  from the target  26  is less than a predefined maximum engagement distance, the effective part  6  of the missile  2  is fired in the flypast and a splitter charge is ejected by the missile  2  in order to engage with the target  26 . In this respect, the missile radar  20  is used as a direction-sensitive approach sensor for controlling direction-dependent firing of the charge of the missile  2 . 
         [0056]    In the exemplary embodiment illustrated in  FIG. 4 , the effective area  52  into which the charge of the effective part  6  is largely ejected, is illustrated by two thickly dashed lines. In a simple embodiment, the charge could be ejected in a belt shape around the missile  2 , with the result that all-round engagement with the target  26  takes place. More effective engagement can be achieved if the effective part  6  is triggered in a directional fashion. The directional triggering is expediently possible into a multiplicity of sectors which can correspond, in particular in their azimuthal extent, to the spatial segments  24 . In the exemplary embodiment shown in  FIG. 4 , the effective part  6  is triggered only into the upper sector in accordance with the upper spatial segment  24  in which the target  26  is located during the flypast. As a result of this directional engagement, a relatively large engagement distance can be achieved. 
         [0057]    The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention:
     2  Missile     4  Rocket motor     6  Effective part     8  Homing head     10  Homing system     12  Control surface     14  Control vane     16  Control unit     18  Transition area     20  Missile radar     22  Radar sensor     24  Spatial segment     26  Target     28  Remote radar, ground radar     30  Location area     32  Cloud     34  Target point     36  Optical distance     38  Location area     40  Target area     42  Optical distance     44  Target area     46  Minimum lock-on range     48  Target point     50  Distance     52  Effective area   r Distance