EP2118615B1 - Method and device for defence against airborne threads - Google Patents

Abstract

A method and apparatus for defending against airborne assault ammunition. The assault ammunition is located with at least one position-locating device. The flight path of the assault ammunition is iteratively calculated using the determined ballistic coefficient of the assault ammunition. A firing control solution is determined for firing a fragmentation-type defense ammunition, which is fired with a large-caliber weapon, especially one having a caliber of at least 76 mm. A fuse of the defense ammunition is set after the firing and/or the defense ammunition is remotely detonated, and after the firing the defense ammunition is ignited or remotely ignited at an ignition time point TZ. Alternatively, the ignition of the defense ammunition is initiated by a proximity igniter disposed in the defense ammunition.

Description

The invention relates to a method and a device for protection against flying attack ammunition. Flying assault ammunition can be used in particular for missiles and artillery and mortar missiles (so-called RAM threat) or cruise missiles, aircraft and parachute objects, and the like. represent. Such a method is known from EP 0 547 391 A1 which is a starting point for independent claims 1 and 6.

Methods are known in which it is attempted to protect objects against flying assault ammunition by firing defensive ammunition with fragmentation action in the direction of the previously located assault ammunition body in order to combat it before striking. At firing of defense ammunition body this is, in particular the shell, decomposed into a plurality of splinters, which are additionally accelerated by the explosion. The spreading of the splinters is usually cone-shaped. If the assault ammunition encounters a splinter, it can be effectively countermeasure provided that the splitter is of sufficient magnitude and velocity to penetrate through the shell of the assault ammunition body.

Such a method, together with the radar equipment required for locating is, for example, in the DE 44 26 014 B4 , of the DE 100 24 320 C2 , of the EP 1 518 087 B1 and the DE 600 12 654 T2 described. Shrapnel grenades are usually used as defense ammunition, which are fired with a launcher. An ammunition with splinter effect is for example in the DE 100 25 105 B4 and in the DE 101 51 897 A1 described. As locating devices for locating and tracking the attack ammunition and for determining the trajectory parameters of the attack ammunition body short-range radars, long-range radars and optical sensors are used.

In the known methods, the objects to be protected mainly include vehicles and devices in the vicinity of the firing weapon. In this case, a short range is understood to mean a radius of a few 100 m to a maximum of 500 m. In the remote area beyond, the procedures can not be used. This is partly due to the fact that the typical fragment grenade launchers used in the process are only able to fire grenades with a firing speed of a few 100 m / s. These can thus only be effective in the near range, since with increasing distance the speed and thus the energy of the defensive ammunition body, which influence the energy of the splinters and which Thus, for a successful fight against the attack ammunition necessary, decreases sharply.

The known methods are thus disadvantageous because they can not be used or only with great effort to protect spatially extended objects. For example, to protect a field camp covering an area of a few square kilometers, a very large number of launchers would have to be set up. Furthermore, in the known methods, the defensive ammunition used used only against special attack ammunition, for example, anti-tank ammunition or missile, so that protection against all assault ammunition is not given.

In addition, a fight at close range is disadvantageous, since this carries with it the danger that by the fight itself, for example by splinters, damage to the objects to be protected takes place. Furthermore, the problem may arise that in the case of unsuccessful control, the time of a further attempt at control is too short.

A disadvantage of the known method is also that the fragmentation grenades are tempiert before firing, ie the ignition is set before firing and given the fragmentation grenade. The disadvantage here is that, inter alia, due to the tolerances of the weapon, the propellant and the ammunition scattering of the shot development time, which includes the time from closing the contact to ignite the primer or - in howitzers - up to the exit of the projectile from the mouth, or the ballistic scattering is present, so that the specified time is unlikely to be the optimal time for the ignition since For example, the defense ammunition body at the time of ignition can be far removed from the attack ammunition. Tolerable results can thus again be achieved only in the near range, since in the fight in the far field inaccuracies, such as an angle error, lead to significantly higher absolute deviations of the distance between the attack ammunition and defense ammunition in the ignition.

Also known is an embodiment in which the defense ammunition body has a proximity fuse. The disadvantage here, however, is that the setting of the correct triggering distance is critical. Further, the assault ammunition can be very small, whereas the determined probable common space may be large due to the inaccuracies of the sensors and the scatters, so that there is a high probability of failure of proximity ignition. In addition, the active sensors, such as an active radar, or the passive sensors, such as an infrared sensor, the proximity fuse can be disturbed by the opponent, whereby ignition can be prevented.

The EP 1 742 010 A1 describes a non-lethal bullet with a programmable and / or adjustable detonator. The non-lethal ammunition can act here, inter alia, by electromagnetic impulses, color, chemical irritants, fog or the like. All applications are equal, that in particular no persons should come to harm by the projectile. For this reason, a detonable detonator is used so that the presence of bullets does not nullify non-lethality.

The DE 10 2005 024 179 A1 describes without specifying the specific applications, a method and an apparatus for temping and / or correction of the ignition timing of a projectile. Here, the velocity of a projectile is measured after firing. By the measurement is closed to the muzzle velocity, which is then used to adjust and / or correct the Zündstellzeit. A particular disadvantage of the method is that further parameters which have an influence on the ignition time are not taken into account.

The invention has the object to provide a method which can be used effectively for protection against flying attack ammunition.

The invention solves the problem procedurally with the features of claims 1 and 6.

It is a basic idea of the invention to determine the trajectory of the assault ammunition body after the location of an assault ammunition by at least one locating device. The faster and more accurately the trajectory is determined, the more likely is successful combat of the assault ammunition. The locating device, which comprises at least one sensor (eg radar, active and / or passive optoelectronic), should provide coordinates and / or speed of the assault ammunition body at sufficiently many times so that the determination can be made, in particular via the determination of the ballistic coefficient c of the assault ammunition the trajectory is possible. The locating device is preferably arranged georeferenced to the weapon.

In a preferred embodiment, the locating device detects the coordinates of the assault ammunition body at discrete times. From this, the speed of the assault ammunition can be determined by subtraction, for example by dividing the velocity difference of the assault ammunition body at two or more times by the elapsed time. Reducing the speed of the assault ammunition is a measure of its specific air resistance. From this specific air resistance, the ballistic coefficient c of the assault ammunition can be determined. This makes it possible to set up and solve the motion differential equations of the outer ballistics of the attack ammunition. As a result, this provides the track of the assault ammunition body as well as its impact point and launch site.

Furthermore, a first fire control solution for firing a defense ammunition body, in particular an explosive projectile, is determined in particular by means of a fire control computer, which can be arranged inside a fire control center. Then the defense ammunition body is fired according to this Feuerleitlösung with a large caliber weapon. The weapon has a caliber of at least 76 mm, preferably 120 mm or 155 mm. Such large-caliber weapons have a long range and a high achievable muzzle velocity of the defensive ammunition, so that even in the long-range fighting the assault ammunition body can be achieved. Preferably, the weapon used has a high precision, in particular with regard to the alignability.

The use of large calibers is also advantageous over the use of small calibers, since in small caliber splinters derive their energy primarily from the web speed, because due to the volume usually only a Zerlegerladung can be installed in a small caliber defense ammunition. However, with increasing distance, the speed and energy of the defense ammunition body decreases sharply. In the case of large calibers, on the other hand, an HE charge can be used, from which the splinters primarily draw their energy, so that this energy is independent of the range. Thus it can be achieved that even in the protection of larger objects the defense ammunition in the near and far, as well as against the hardest attacking object are equally effective. The anti-ammunition body should be at least 800 m away. However, a fight can also take place at much greater distances, for example at a distance of 3000 m, with the probability of control decreasing at greater distances.

The defensive ammunition body is ignited in a first embodiment of the invention after firing at a time T _Z or remotely ignited directly. In a second embodiment according to the invention, the defense ammunition body merely has a proximity fuse, which initiates the ignition of the defense ammunition body when the attack ammunition is within the effective range of the fragment-protective defense ammunition body.

In the first embodiment according to the invention, the exact ignition time T _Z , especially in the long-range, is essential for the effectiveness of the control, since even small deviations due to the high level of ignition Speeds and long distances can lead to large deviations between the predicted and the actual Zündort. For this reason, a defensive ammunition body is used, which is stampable after firing and / or remotely ignitable.

The defense ammunition body can have a receiving unit for receiving signals which have been transmitted by a transmitting unit, which is connected in particular to the fire control computer. If the firing of the defensive ammunition body is remote-controlled, in particular radio-controlled, the determined ignition time T _Z can be used to ignite the defense ammunition body at this time. The receiving unit in this case receives remote control signals, which lead via a particular programmable ignition control unit to the ignition. However, since also the transmission from the transmitting to the receiving unit requires a not exactly predictable time, in a preferred embodiment, a sufficient time before ignition, tempier signals, which contain the detected ignition timing T _Z , transmitted to the receiving unit of the defense ammunition. The ignition control unit then ignites the defense ammunition to the predetermined ignition, which can be dispensed with in this embodiment to a direct remote ignition. An increased security can be achieved here, if the reception of the ignition timing T _{Z is} confirmed by the defense missile, for example to the Feuerleitstelte, so that the correct reception of the correct ignition timing T _{Z is} ensured.

Advantageously, the determination of the ignition timing T _Z will take place after the defense ammunition has been fired. In particular, thus, the further trajectory of the attack ammunition body can be considered. Furthermore, the movement of the Defensive missile are considered in the determination of the optimal ignition timing T _Z. For this reason, it is advantageous if the velocity v _{M of} the defense ammunition body and the direction at a specific time T _M , is determined by means of at least one measuring device. In this case, they can be used to form the reference for the spatially fixed coordinate system of the ballistic calculations.

In one embodiment, the speed v _{M may be} the muzzle velocity v ₀ , wherein in this case the measuring device may in particular comprise a coil which is arranged in particular in the region of the mouth opening of the weapon barrel of the weapon. A coil for measuring the muzzle velocity of a projectile, for example, in the EP 1 482 311 A1 described in principle.

In another embodiment, the time T _{M is} a time at which the defense ammunition has already left the weapon. In this case, the measuring device may in particular comprise a radar device. In order not to unnecessarily lose time in this embodiment, the measuring device can be designed to be directional and be directed in the direction of the direction of firing already and at the time of firing the defensive ammunition. This can be achieved for example by a coupling between the weapon and the measuring device.

The determined speed v _M and the direction at the time T _M can be taken into account in the determination of the time T _{Z of} the ignition of the defense ammunition. Thus, the actual, time-dependent trajectory of the defense missile can be determined more accurately, so that a higher probability of a successful Is achieved. Therefore, a measuring device with a high accuracy should be used. In particular, a measuring device is used whose standard deviation in the velocity determination is less than 0.5 m / s. Furthermore, the signal propagation times should be kept short, preferably real-time capable components should be used.

The determination of the ignition timing T _Z can be made such that the time is determined in which there is a high, preferably the highest probability of successful combat, and in particular from the product of the hit probability, which indicates whether a splinter hits the attack ammunition, with the probability of destruction, indicating whether this splinter is capable of destroying the shell of the assault ammunition body. This probability of control is thus dependent on various parameters. The more parameters are taken into account in the determination of the ignition timing T _Z , the better the prediction.

The measurements and determinations of the measuring device and the locating device may be subject to errors, for example inaccuracies in the timing, the determination of the speed, in the angle determination and the distance measurement may occur. If these tolerances are known, they should be taken into account, as they have a bearing on the probable location of the attacking and defense ammunition bodies in a manner similar to ballistic scattering, such as deviations of azimuth and elevation of the weapon, as well as the shot development time.

Also, the nature of the assault ammunition, in particular its hardness, may have an influence on the optimal ignition timing T _Z. The military hardness of an assault ammunition body depends essentially on its wall thickness. In particular, there is a positive correlation between caliber and wall thickness, ie larger caliber usually have a greater wall thickness and are thus militarily harder. In this respect, the ignition should take place at a high hardness of the attack ammunition rather late, so that although the probability of likelihood lower but the probability of destruction due to the greater kinetic energy is greater, thus achieving a high probability of control.

In addition, the nature of the defensive ammunition body, in particular its properties such as splinter matrix, which includes the spatial distribution of the splitter by number and size, splitter cone build-up time and inaccuracies of the Tempierzeit, ie the scattering of the time of the actual initiated by the ignition control ignition at set ignition, of importance , Furthermore, the shot development time of the defense ammunition body and the ballistic scattering can influence the ignition timing T _Z.

The determination of the ignition timing T _Z should be as fast as possible because the time between the firing and the firing of the defense ammunition body is short. The time of flight at a control distance of eg 1000 m is typical projectile speeds only of the order of 1 s, and in this period to the velocity v _M of the defensive ammunition measured, a new fire control and the ignition timing calculated from T _Z and transfer the data to the initiator become. Therefore, fast algorithms are needed to calculate the fire control solution. For this reason, an analytical procedure should be used.

Added to this is the aspect of the data transmission between different system components, for example between the locating devices, fire control computer, measuring device, transmitting and receiving device and ignition control unit. Thus, in addition to a real-time capable operating system of the fire control computer and real-time capable bus systems each component should be designed for fast transmission of data.

In an advantageous embodiment, the defense ammunition body additionally has a proximity fuse. It is advantageous here that in the case in which the determined ignition time was actually too late, there is a certain chance that the defense ammunition body is previously initiated by means of the proximity fuse.

In the second embodiment according to the invention, the defense ammunition body only has an approach fuse as an igniter. This initiates the ignition when the defensive ammunition is in a particular adjustable distance to the attack ammunition. This is sufficient for effective control in cases where the scattering of the system is so small that it is highly probable that the assault ammunition reaches the effective range of the splinter-acting defense ammunition body.

In order to determine the trajectory, the ballistic coefficient of the assault ammunition body, which is essentially determined from the ratio of cross-sectional area to mass of the assault ammunition body, is initially determined in both embodiments. With their help The equations of motion of the outer ballistics of the attacking ammunition can be set up and solved analytically or numerically. By a forward calculation can thus be determined the place of impact of the attack ammunition and the data for the determination of the Feuerleitlösung to combat the assault ammunition. Furthermore, the launch site of the attack ammunition body can be determined by a backward calculation.

A basic idea of the method of determining the ballistic coefficient and the trajectory is that the air resistance which decelerates the assault ammunition during flight is determined from the decrease in its kinetic energy. In this case, this mass-related air resistance force can be determined from the difference between two mass-related kinetic energies, based on the distance covered in the process.

The kinetic energy of the attack ammunition at a location of the trajectory can be calculated from their speed, the speed in turn can be determined from two Radarortmessungen (time and place). The air resistance is represented by the ballistic coefficient. This is essentially dependent on the projectile velocity, the projectile geometry and atmospheric properties. By knowing the ballistic coefficient, the equations of motion for the attack ammunition can be solved numerically and the trajectory can be calculated from a location averaged from two radar measurements. If terrain information is available, by comparing the calculated trajectory with the terrain profile in a suitable reference system, the geographic coordinates (length, width, height) of the launching point of the attack ammunition body can be or the meeting point with the defense ammunition body.

Thus, only four measurements, in particular pure distance measurements along an axis, preferably the radar beam, are sufficient for determining the trajectory, since two radar location measurements are required for calculating the kinetic energy at a location of the trajectory, as explained above. In order to be able to determine the required ballistic coefficient c , on the other hand, the kinetic energy must be known in another location, so that two further measurements are necessary. Due to the fact that the locating device only needs to record four measuring points, the method is sufficiently fast.

One advantage of the presented method is, on the one hand, the high accuracy of the calculated trajectory and thus of the predicted meeting point or place of launch of the assault ammunition body. On the other hand, the method allows the formula work to be able to determine the necessary sensor inaccuracies with the help of error propagation in order to equip early-warning and air defense systems with specific properties and to test their suitability. This can be achieved by the special form of the motion differential equations, the separation of the drag coefficient into fixed and variable components and by applying a specific reference function for its speed-dependent component. Thus, it can be achieved that the method only determines the fraction that is actually dependent on the assault ammunition, which also enables a classification.

The classification of the located assault ammunition can be carried out by means of the ballistic coefficient. This is due to the fact that the ballistic coefficient for a type of attack ammunition is always in a constant narrow range. If these ranges of values are known, which can be obtained, for example, by evaluating shooting tables, an attack ammunition type can be assigned for a specific coefficient.

The first determined Feuerleitlösung, after which the defense ammunition is fired, is preferably dimensioned such that the compensation of tolerances used, sensors containing locating and measuring device and used, effectors containing weapon and defensive ammunition by the firing point determined after firing T _Z possible is.

By determining the likelihood of successful control, the ammunition requirement, i. the nature and number of defense ammunition bodies and the required deployment. When deployed to protect a field camp, it can also be used in planning to determine how weapons should be deployed to provide effective protection against various attack scenarios.

The defense ammunition can be fired in accordance with the determined ammunition requirement, as long as the successful combat of the attack ammunition body is not recognized. Here either a weapon can fire several defense ammunition or several weapons can be used. In this context, various confidence levels of likely successful control can be given. At a high confidence level is also aimed at a high probability of successful control. For this reason, the number or type of defense ammunition can be adjusted according to the desired level of confidence so as to influence the likelihood of successful control. In the determination of the munition requirement, it is also advantageous to take into account the parameters already mentioned above for determining the ignition timing T _Z , ie preferably the consideration of measurement inaccuracies of the measuring device, in particular in the determination of time, speed, azimuth, elevation and / or distance, Measuring inaccuracies of the locating device, in particular in the determination of time, speed, azimuth, elevation and / or distance, type of attack ammunition, in particular its hardness, type of defensive ammunition, in particular its properties such as splinter matrix, splitter cone construction time, inaccuracies of the tempier time, shot development time of the defensive ammunition body and ballistic Scattering.

As an advantageous safety aspect, it can be provided that the defensive ammunition body is pre-preheated before firing to a point in time T _which predicts the time T _B predicted by the firing solution determined before the firing, in which the defensive ammunition strikes the ground when ignited. Thus, it is ensured that, for example, in the case where the transmission of the ignition timing or the remote control signals have not been properly transmitted, the defense ammunition body ignites before striking the ground, so that no persons or facilities on the ground come to harm. However, so that the ignition is not too early, especially not before the time at which the signals are received by the defensive ammunition can provision is made for the time T to lie _{ahead of} the time T _A , which is determined by the ignition time T _{Z of} the defense ammunition body predicted by the firing solution determined before the firing.

In order to achieve high accuracy in the determination of the trajectory parameters of the assault ammunition body with little effort, after the first location of the attack ammunition by the locating device, the location data to a second locating device, in particular a Zielfolderadargerät be passed, which the measurement of the determination of the trajectory necessary sizes. In this case, a round search radar can be used as the first locating device.

Since the trajectory of the assault ammunition body is known, a warning, such as an audible warning, for the area determined by the detected trajectory of the assault ammunition body impact point is delivered to the ground, so that in this area preventive measures can be taken to prepare for the case to be that the fight against the attack ammunition body was not successful.

It is also advantageous if it is concluded from the determined trajectory of the first located assault ammunition on the launch site, so that preferably with the same weapon that fights the attack ammunition, even the attacker, who can often be far away, can be combated.

Fig. 1

ein Feldlager mit vier Waffen zum Schutz gegen fliegen- de Angriffsmunitionskörper in einer schematischen Dar- stellung,

Fig. 2

ein Flussdiagramm zum Ablauf des Verfahrens,

Fig. 3

ein 3D-Koordinatensystem zur Radarortgeometrie,

Fig. 4

eine 2D-Projektion der Radarortgeometrie nach Fig. 3,

Fig. 5

ein weiteres Koordinatensystem zur Radarortgeometrie,

Fig. 6

ein Koordinatensystem zur Geometrie des Splitterkegels,

Fig. 7

ein Koordinatensystem zur Geometrie des Splitterkegels mit Ellipsenzylinder,

Fig. 8

ein Diagramm zum Munitionsbedarf zur erfolgreichen Be- kämpfung bei einem Konfidenzniveau von 50%,

Fig. 9

ein Diagramm zum Munitionsbedarf zur erfolgreichen Be- kämpfung bei einem Konfidenzniveau von 99%, und

Fig. 10

eine Vorrichtung zum Schutz gegen Angriffsmunitionskör- per in einer schematischen Darstellung.

Possible embodiments of the invention will be described with reference to FIGS FIGS. 1 to 10 explained. Show it:

Fig. 1

a field camp with four weapons for protection against flying assault ammunition in a schematic representation,

Fig. 2

a flow chart for the procedure of the method,

Fig. 3

a 3D coordinate system for radar location geometry,

Fig. 4

a 2D projection of the radar location geometry Fig. 3 .

Fig. 5

another coordinate system for radar location geometry,

Fig. 6

a coordinate system for the geometry of the fragment cone,

Fig. 7

a coordinate system for the geometry of the fragment cone with elliptical cylinder,

Fig. 8

A chart of ammunition needs to successfully fight at a confidence level of 50%.

Fig. 9

a chart on ammunition requirements for successful combat at a confidence level of 99%, and

Fig. 10

a device for protection against assault ammunition in a schematic representation.

The method and the device are for the protection of a spatially extended field camp 1 with quadrangular base after Fig. 1 used. It is placed in each corner of the field camp, a device 20, which is schematically in Fig. 10 is shown. It has a weapon 2, which can fire Abwehrmunitionskörper 3 with splinter effect, a first locating device 12, a second locating device 5, a measuring device 10, a signal transmission unit 7 and a Feuerleitrechner 6 on. The weapon 2, the locating device 5, the measuring device 10 and the signal transmission unit 7 are connected via data lines 11 with the Feuerleitrechner 6. For optimum control the locating device 5 and the weapon 2 are spatially close to dislocate. The defense ammunition body 3 includes a Ignition control unit 9, a signal receiving unit 8, an igniter 13 and an explosive charge 14. The arrangement in the region of the corners of the field camp 1 can be avoided to shoot over the field camp 1 in the course of combating assault ammunition 4 with the defense ammunition 3. Another advantage of using multiple weapons 2 is that the likelihood of frontal combat increases with the smallest possible impact angle, which is advantageous due to the high speed difference between assault ammunition 4 and splinters.

• I. Ortung des Angriffsmunitionskörpers 4 mit einer ersten Ortungseinrichtung 12;
• II. Übergabe der Zieldaten an eine zweite Ortungseinrichtung 5 und Zielverfolgung;
• III. Berechnung der Feuerleitlösung durch den Feuerleitrechner 6;
• IV. Klassifikation des Angriffsmunitionskörpers 4;
• V. Richten der Waffe 2;
• VI. Abfeuern des Abwehrmunitionskörpers 3, um eine Bekämpfung in der gewünschten Entfernung durchzuführen;
• VII. Messung der Abwehrmunitionskörpergeschwindigkeit v_M und Übermittlung der Daten an den Feuerleitrechner 6;
• VIII. Berechnung einer korrigierten Feuerleitlösung und Bestimmung des Zündzeitpunkts T_Z;
• IX. Fernübermittlung des Zündzeitpunkts T_Z an die Zündsteuereinheit 9, (alternativ: direkte Fernauslösung des Zünders 13)
• X. Zündung der Sprengladung 14, Ausbildung des Splitterkegels

The control procedure is according to Fig. 2 as follows:

• I. Locating the assault ammunition 4 with a first locating device 12;
• II. Transfer of the target data to a second locating device 5 and target tracking;
• III. Calculation of the Feuerleitlösung by the fire control computer 6;
• IV. Classification of the assault ammunition 4;
• V. Aligning the weapon 2;
• VI. Firing the defensive ammunition body 3 to perform combat at the desired distance;
• VII. Measurement of defense ammunition body speed v _M and transmission of the data to the fire control computer 6;
• VIII. Calculation of a corrected Feuerleitlösung and determination of the ignition timing T _Z ;
• IX. Remote transmission of the ignition timing T _Z to the ignition control unit 9, (alternatively: direct remote release of the igniter 13)
• X. Ignition of the explosive charge 14, formation of the fragment cone

It is generally noted that the order of the steps presented does not necessarily correspond to the order given got to. Thus, for example, the classification of the attack munitions body 4 can be carried out even after judging the weapon 2.

To I. Locating the assault ammunition 4 with a first locating device 12:

As the first locating device 12, a known Rundsuchradar is used.

As an assault ammunition 4 is a mortar shell (82 mm) of cast iron with a mass of 3.31 kg and a wall thickness of about 9 mm to 10 mm is considered as an example, which at a launch speed of 211 m / s at a distance of 3040 m below was fired at an angle of 45 °.

To II. Transfer of the target data to a second location device 5 and target tracking:

After locating by the first locating device 12, the target data is transferred to a second locating device 5 configured as a destination follower radar for further tracking of the target. This second locating device 5 comprises a radar system, which comprises a radar sensor of the designation MWRL-SWK. This is a Russian air traffic control radar for airfields with a radar range of 1 km to 250 km, standard deviation in azimuth and elevation of 0.033 °, standard deviation in the distance measurement of 10 m, standard deviation in the time determination of 66.7 ns and an angular velocity of 18 ° / s up to 90 ° / s.

For the purpose of determining the error budget of the second locating device 5, the bases of the locating measurements are specified at this point in order to be able to calculate the radar location of the assault ammunition 4 using the measured variables of an imput radar azimuth a , elevation ε and the time t . Alternatively, for a radar device with a rotating antenna, the radar angular velocity is used to calculate three radar locations.

$$z_i=x_i\tan {\alpha }_i$$

mit a_i als dem Azimutwinkel des Angriffsmunitionskörpers 4 vom Radar, x_AP und z_AP als Koordinaten des Abschusspunktes sowie ψ als Azimut der Schusslinie gegenüber der Abszisse des Referenzsystems.The coordinates of the location of the assault ammunition 4 ( i = 1 ... 4) are determined using the location trigonometry according to Fig. 3 and Fig. 4 determined (equation 1a and equation 1b): $$x_i=\frac{z_{\mathit{AP}}-x_{\mathit{AP}}\tan \psi }{\tan {\alpha }_i-\tan \psi }$$

$$z_i=x_i\tan {\alpha }_i$$

with a _i as the azimuth angle of the assault ammunition 4 from the radar, x _AP and z _AP as coordinates of the launch point and ψ as the azimuth of the firing line with respect to the abscissa of the reference system.

$$R_i=\sqrt{x_i^2+z_i^2}$$

The y coordinate of a radar location i is determined from the distance of the location of the assault ammunition 4 from the radar R and the elevation of the radar beam ε (Eq 2a and GL 2b): $$y_i=R_i\tan {\epsilon }_i$$

$$R_i=\sqrt{x_{\mathrm{<figure-callout\; id="2"\; label="i"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">i</figure-callout>}}^2+{\mathrm{<figure-callout\; id="2"\; label="z\; i"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">z\; </figure-callout>}}_i^{}}$$

wird genutzt, um die dem Radarort entsprechende Flugzeit des Angriffsmunitionskörpers 4 und die Höhenkoordinate des Radärortes y_i aus der Lösung des Differentialgleichungssystems zu berechnen. Damit lässt sich dann der gesuchte Elevationswinkel des Radars bestimmen (Gl. 4): $${\epsilon }_i=\arctan \frac{y_i}{\sqrt{x_i^2+z_i^2}},i=1\dots 4$$

The horizontal distance of the radar location from the launch point (Eq. $$x_{R_i}=\sqrt{{\left(x_i-{\mathrm{<figure-callout\; id="2"\; label="x\; AP"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">x\; </figure-callout>}}_{\mathit{AP}}\right)}^2+{\left(z_i-{\mathrm{<figure-callout\; id="2"\; label="z\; AP"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">z\; </figure-callout>}}_{\mathit{AP}}\right)}^2}$$

is used to calculate the radar location corresponding time flight of the assault ammunition 4 and the altitude coordinate of Radärortes y _i from the solution of the differential equation system. With this, the desired elevation angle of the radar can be determined (equation 4): $${\epsilon }_i=\arctan \frac{y_i}{\sqrt{x_i^2+{\mathrm{<figure-callout\; id="2"\; label="z\; i"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">z\; </figure-callout>}}_i^{}}}.i=1...4$$

sowie der Distanz Abschusspunkt-Radarort ergeben (Gl. 6a und Gl. 6b): $$x_i=\left(x_{R_i}-x_{R_{i-1}}\right)\cos \psi +x_{i-1}$$

$$z_i=\left(x_{R_i}-x_{R_{i-1}}\right)\sin \psi +z_{i-1}$$

mit i= 2...4.In the case of a radar device with a rotating antenna, let the first azimuth angle of the location of the assault ammunition 4 and thus its coordinates be Eq. 1, so that the three following radar loci result from the radar angular velocity ω (Eq. $$t_i={\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">t</figure-callout>}}_1+\frac{2\pi }{\omega }\left(i-1\right).i=1...4$$

and the distance of the launch point radar location (Eqs 6a and Eq 6b): $$x_i=\left(x_{R_i}-x_{R_{i-1}}\right)\cos \psi +x_{i-1}$$

$$z_i=\left(x_{R_i}-x_{R_{i-1}}\right)\sin \psi +z_{i-1}$$

with i = 2 ... 4.

The searched azimuth angles are calculated as follows (equation 7): $${\alpha }_i=\arctan \frac{z_i}{x_i}.i=2...4$$

The elevation angles ε _i result from Eq. 4th

To III. Calculation of the Feuerleitlösung by the fire control computer 6:

In order to determine a first Feuerleitlösung, first the equations of motion of the assault ammunition 4 must be solved.

$$\mathit{pʹ}=\frac{\mathrm{d}p}{\mathrm{d}x}=-\frac{g}{{\upsilon }_x{\left(x\right)}^2}$$

$$\mathit{yʹ}=\frac{\mathrm{d}\mathit{y}}{\mathrm{d}x}=p\left(x\right)$$

$$\mathit{tʹ}=\frac{\mathrm{d}t}{\mathrm{d}x}=\frac{1}{{\upsilon }_x\left(x\right)}$$

mit:

• v: Geschwindigkeit
• v_x : Geschwindigkeitskomponente in x-Richtung
• c₂ (M_a): Luftwiderstandskoeffizient, von der Mach'schen Zahl und dem ballistischen Koeffizienten abhängig
• K_y : Faktor zur Korrektur der Geschwindigkeit für die Höhe
• y: Weg in y-Richtung
• x: Weg in x-Richtung
• p: tαnθ
• g: Erdbeschleunigung
• t: Zeit
• Θ: Schusswinkel.

The equations of motion of the projectile 4 to be counteracted are derived from the set of center of gravity, whereby the projectile 4 is regarded as a point mass and simplistically acts on this as external forces only the air resistance and the gravitational force. They are applied in the path-dependent form (Eqs 8a to 8d): $${\upsilon }_x^{\text{'}}=\frac{\mathrm{d}{\upsilon }_x}{\mathrm{d}x}=-{\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">c</figure-callout>}}_2\left(\mathit{Ma}\right)\upsilon \left(x\right)K_y$$

$$\mathit{p\text{'}}=\frac{\mathrm{d}p}{\mathrm{d}x}=-\frac{G}{{\upsilon }_x{\left(x\right)}^2}$$

$$\mathit{y\; \text{'}}=\frac{\mathrm{d}\mathit{y}}{\mathrm{d}x}=p\left(x\right)$$

$$\mathit{t\; \text{'}}=\frac{\mathrm{d}t}{\mathrm{d}x}=\frac{1}{{\upsilon }_x\left(x\right)}$$

With:

• v : speed
• v _x : velocity component in x-direction
• c ₂ ( M _a ) : aerodynamic coefficient, depending on the Mach number and the ballistic coefficient
• K _y : factor for correcting the speed for the altitude
• y : way in y direction
• x : path in x- direction
• p: tαnθ
• g : acceleration of gravity
• t : time
• Θ: shooting angle.

The coefficient c ₂ (Ma) is composed of a shell-dependent, an empirical velocity-dependent and an atmospheric fraction: c ₂ (Ma) = f ₁ (c) * f ₂ (c _Ma ) * f ₃ (c _a ). The projectile-dependent fraction f ₁ (c) contains the ballistic coefficient c = A / m. The velocity-dependent fraction f ₂ (c _Ma ) is present as a reference function, which was determined experimentally or calculated by known methods and can be used for ballistic projectiles. The third fraction f ₃ (c _a ) depends on the atmospheric conditions (eg air pressure, temperature). For example, be regarded as constant for short shooting distances with low altitudes. If necessary, corrections for the standard values of temperature and barometric pressure can be added to this part.

The differential equation system for describing the projectile motion is solved by conventional numerical methods. Forward integration determines the point of impact at the destination. The backward calculation gives the point of launch. For this purpose, the air resistance coefficient c ₂ (M _a ) is required as an input parameter.

• Der ballistische Koeffizient c kann aus der am Geschoss 4 wirkenden Luftwiderstandskraft bestimmt werden, wobei sich diese Luftwiderstandskraft aus der Differenz der kinetischen Energie des Geschosses 4 am Ort A und B und der zwischen diesen beiden Orten gemessenen Wegstrecke ergibt (siehe Fig. 5). Die kinetische Energie in A und B lässt sich dazu durch die Geschossgeschwindigkeiten ausdrücken.

The initially unknown ballistic coefficient c of the projectile 4 is thus the decisive parameter for starting from a location B determined from radar measurements by iterative numerical solution of the equations Eq. 8a to Eq. 8d to calculate the further trajectory and for y = 0 the place of impact. The following method for the experimental determination of air resistance is used to determine the ballistic coefficient c and thus the air resistance coefficient c ₂ ( Ma ):

• The ballistic coefficient c can be determined from the aerodynamic force acting on the projectile 4, this aerodynamic force resulting from the difference between the kinetic energy of the projectile 4 at location A and B and the distance measured between these two locations (see Fig. 5 ). The kinetic energy in A and B can be expressed by the projectile velocities.

Decisive here is that the velocity-dependent fraction f ₂ (c _Ma ) is known by the reference function and the part dependent on the atmosphere f ₃ (c _a ) is assumed to be constant. Therefore, only the proportion of the air resistance coefficient c ₂ (M _a ) is to be determined, which actually depends on the projectile. This proportion is called the ballistic coefficient c .

wobei c₂(M_a) wie folgt definiert ist (Gl. 10): $$c_2\left(\mathit{Ma}\right)=\frac{\rho }{2}\cdot \frac{c_{W}A}{m}$$

The determination of the air resistance coefficient c ₂ (M _a ), from which the ballistic coefficient c can be easily calculated, results from the equilibrium of forces with the known resistance function and the mean deceleration force of the air resistance (equation 9): $$F_W=\frac{\mathrm{<figure-callout\; id="2"\; label="\rho "\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">\rho </figure-callout>}}{2}{c}_W{\mathrm{<figure-callout\; id="2"\; label="\upsilon "\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">\upsilon </figure-callout>}}^{2}A=m{a}_W$$

where c ₂ (M _a ) is defined as follows (equation 10): $${\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">c</figure-callout>}}_2\left(\mathit{Ma}\right)=\frac{\mathrm{<figure-callout\; id="2"\; label="\rho "\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">\rho </figure-callout>}}{2}\cdot \frac{c_{W}A}{m}$$

With this definition and equation 9, and then adding the velocity correction K _y already used in the equation system 8, the determination equation for c ₂ (M _a ) (equation 11) results: $${\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">c</figure-callout>}}_2\left(\mathit{Ma}\right)=\frac{a_{\mathrm{<figure-callout\; id="2"\; label="W\; \upsilon \; m"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">W\; </figure-callout>}}}{{\upsilon }_m^{}}$$

$${\upsilon }_m=\frac{{\upsilon }_{x_A}+{\upsilon }_{x_B}}{2}$$

For the delay a _w and the mean horizontal velocity v _m (Eqs 12 to 13): $$a_W=\frac{1}{2}\frac{{\upsilon }_{x_A}^2-{\upsilon }_{x_B}^2}{x_{\mathit{FROM}}}$$

$${\upsilon }_m=\frac{{\upsilon }_{x_A}+{\mathrm{<figure-callout\; id="2"\; label="\upsilon \; x\; B"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">\upsilon \; </figure-callout>}}_{x_B}}{2}$$

By subsequently determining the ballistic coefficient c = A / m from the air resistance coefficient c ₂ (Ma), strictly speaking only for the location of the measurement, c ₂ (Ma) can be adapted to changed speeds of the assault ammunition and changed atmospheric conditions and thus more accurate results achieve in the iterative solution of the equation system 8. In addition, this allows the described classification of the attack ammunition.

The horizontal distance of the averaged radar locations A and B results from the geometry (Eq.14): $$x_{\mathit{FROM}}=\sqrt{{\left(x_B-{\mathrm{<figure-callout\; id="2"\; label="x\; A"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">x\; </figure-callout>}}_A\right)}^2+{\left(z_B-{\mathrm{<figure-callout\; id="2"\; label="z\; A"\; filenames="imgf0005.png,imgf0008.png"\; state="\{\{state\}\}">z\; </figure-callout>}}_A\right)}^2}$$

The velocities and the spatial coordinates in the x and z directions at locations A and B are calculated from two projectile locations determined by a pulse radar with respect to the coordinate system of the radar device. Due to the special form of the motion differential equations, which results from the conversion of the time-dependent form of the motion differential equations into a location-dependent form, only the horizontal components of the speed and the horizontal distance between the averaged radar locations A and B are required. The fact that the track of the attack ammunition body is considered only in its projection on an axis (here: x-axis), can be dispensed with a complete track tracking in all three axes. Thus distance measurements are sufficient. Thus, a rapid determination of the necessary measurements for the determination of the trajectory can be achieved.

The effect of radar site measurement errors on the length spread (width of weft strip 2ω containing x% (ie 50%) of all fired shots N when the center meeting point lies on the centerline of this strip), the width spread (analogous to length spread, however, the strip lies perpendicular to the weft direction and horizontally) as well as the Circular Error Probability (CEP) of the meeting point, which is determined by the radius around the meeting point, in the circular area of which x% of all the shots N issued, is determined in order to determine the error budget of the radar sensors of the locating device 5. All systematic measurement errors are eliminated by adjustment or calibration, so that only the measurements of the azimuth a , the elevation ε and the time t are subject to random error influences. It is assumed that these are normally distributed with the mean value μ = 0 and the standard deviations σ _a , σ _ε , α _{t are} given by the respective measuring devices.

In the case of a locating device 5 with a rotary antenna, its angular velocity ω is also subject to the standard deviation σ _ω , the size of which results from the error of the time measurement.

With the ballistic coefficient c , starting from the averaged bullet location B, iterative numerical solution of the equations Eq. 8a to Eq. 8d the further trajectory and the meeting point are determined. Therefore, the errors in the radar location measurements propagate beyond the ballistic coefficient to the meeting point and determine its sought-after dispersion.

To determine the length dispersion, first the standard deviation σ _{c of} the ballistic coefficient c is calculated from the random errors of the azimuth, the elevation and the time, wherein the time error with the speed of light in vacuum can be determined from the range error of the radar device 5. In a radar device 5 with rotating antenna, the standard deviation of the angular velocity results from the time error. It will be in this context the laws of Gaussian error propagation are applied.

Subsequently, with the approach of varying perturbation parameters by generating normally distributed random numbers for the ballistic coefficient and numerical solution of the differential equation system, the length dispersion of the meeting point can be determined. From the measurement errors of the time and the azimuth and the underlying locating geometry, the width spread is calculated directly.

The Circular Error Probability (CEP) of the impact location is calculated from the latitude and longitude scatter of the impact location. This is calculated numerically according to a method presented in the literature with the standard deviations in the x and z directions and the associated covariance cov (x, z) as input parameters for the desired confidence level.

In the present embodiment, the assault ammunition 4 is to be fought at a distance of 1000 m in a target height of 500 m. This leads to a launch angle of about 26.6 °. The location distance of the radar is also 1000 m.

To IV. Classification of the assault ammunition 4:

A classification of the located assault ammunition 4 is carried out on the basis of the ballistic coefficient c . The ranges of values of the ballistic coefficient c of various possible and likely to be expected assault ammunition bodies 4 were previously obtained by evaluation of shots. Thus everyone can ballistic coefficients c are assigned to a type of an assault ammunition 4. This assignment is carried out by the fire control computer 6.

The application of the determination of the type of assault ammunition 4 can be limited only in the rare cases when the ranges of the coefficient c overlap. Irrespective of this, however, the location accuracy of the radar sensor used by the locating device 5 has a significant influence on the uniqueness of the result.

In any case, from the knowledge of the ballistic coefficient, it is possible to gain important information about the attacking munition 4 to be combated. If the attack ammunition 4 is known, e.g. Its caliber and hardness can be determined, for example, from a table.

To V. Aligning the weapon 2:

As a weapon 2 a Panzerhaubitze is used. This self-propelled artillery gun is able to fire projectiles 3 with a caliber of 155 mm. After straightening the gun barrel of the Panzerhaubitze 2 the firing time is waited.

To VI. Firing the defensive ammunition body 3 to combat at the desired distance:

As a defense ammunition body 3, a HE-explosive projectile (155 mm) is used as an example, which is fired with the Panzerhaubitze 2. To achieve a high muzzle velocity, the largest possible propellant charge is used. The splinter mass distributions and splintering speeds of the defensive ammunition body 3 were previously determined during blasting experiments in a forecourt. The splitter cone build time is considered to be the time at which the diameter of the splitter cone is equal to the radar CEP area.

The fragmentation effect of explosive projectiles results from the dismantling of the projectile shell into thousands fragments, which are accelerated by the explosion in addition. The splitter mass distributions determined in the course of blasting and the splitter speeds are evaluated after a series of blast tests. From this, the experimental splitter matrices known from the literature are determined, in which the splinters are classified according to their splitter outlet angle and their mass.

Upon initiation of the explosive charge 14 on the trajectory, a splitter cone opened in the direction of movement forms, the opening angle of which depends on the velocity of the defense ammunition body 3, the initial velocity of the splitter and the splitter outlet angle. Since the fragmentation distribution in a forecourt was determined under static conditions, the translational velocity of the projectile 3 is to be vectorially superimposed at the initiation time and the dynamic splitter outlet angle to be determined. Due to the air resistance, the speed of the splinters decreases with increasing distance from the initiation site.

The number of effective splinters depends on whether the kinetic energy of the splinters is greater than the minimum energy required to destroy the assault ammunition 4 at an assumed angle of incidence. The splinters that fulfill this condition are effective. The minimum energy results from the energy needed to break through the bullet wall of a RAM target and to detonate the explosive charge. The well-known from the literature shell formula de Marre is used to estimate the breakdown energy of assault ammunition 4.

In the described attack ammunition 4, for example, an energy of 1200 J can be specified as the minimum energy.

Based on the impact sensitivity of typical explosives, the energy is determined to bring the explosive of the attack ammunition 4 to the explosion. The impact of a splitter on an assault ammunition body 4 is modeled as a plastic impact process and the occurring conversion of mechanical into internal energy ultimately corresponds to the energy that is available to destroy the assault ammunition 4 available.

To VII. Measurement of defense ammunition body speed v _M and transmission of the data to the fire control computer 6:

The measurement of the speed v _M can be carried out by means of a radar. By determining can be concluded that the muzzle velocity v ₀ . When measuring the velocity v _M by means of a radar device, the Doppler method or the pulse transit time method can be used.

In an alternative embodiment, a real-time v ₀ coil is integrated in the tube of the weapon 2 as a measuring device 10, which provides by induction the initial velocity of the Abwehmunitionskörpers 3 of the current shot and the time of measurement. It also forms the reference for the spatially fixed coordinate system of ballistic calculations.

To VIII. Calculation of a corrected Feuerleitlösung and determination of the ignition timing T _z :

The determination of the ignition timing T _Z by means of the corrected Feuerleitlösung should take place as quickly as possible, because the time between the firing and the ignition of the defense ammunition 4 is short. For the calculation of the corrected Feuerleitlösung a method is used, which solves the differential equations of the external ballistics analytically. In this case a mathematical function, namely Lerch's Phi, is used. With a special approximation method, such as the Gaussian least squares method, the values of k ₁ and k _{2 can be obtained} from the equation _cw = k ₁ * Ma k ₂ from the service firing charts (measured values). The quantity c _w gives the ratio of the air resistance between a projectile and an infinitely extended flat plate as a function of the Mach number. Only with a correct c _w value can the correct air resistance and thus the correct trajectory of a projectile be determined. By approximating this equation, the motion differential equations of external ballistics for Mach numbers> 1 (supersonic) can be solved analytically. This allows a fast calculation of Feuerleitlösungen done because no numerical integration is required.

The method can also with the in the DE 10 2005 023 739 A1 be combined described methods. The method described there is used to determine the Feuerleitlösung in the presence of a relative movement between the weapon and the target. Such a relative movement is formed in the present context by the movement of the attack ammunition body while the weapon is stationary.

To determine the ignition timing T _Z , the parameters are taken into account, which have an influence on the optimum ignition timing. The ignition timing T _Z should be the time when the greatest likelihood of successful control exists. Due to the scatters and tolerances, only a probable residence space of the attacking and defense ammunition body and a probable development of the fragmentation effect after ignition can be given.

• Einerseits soll der Abstand zum Ziel 4 möglichst klein sein, weil bedingt durch den Luftwiderstand mit zunehmender Entfernung vom Zündort die Anzahl der wirksamen Splitter abnimmt.
• Andererseits soll am Ziel 4 etwas vorbeigeschossen werden, da die größten Splitterzahlen im Randbereich des Splitterkegels auftreten.

In general, the assault ammunition 4 and especially its caliber surface is small. On the other hand, due to the inaccuracies in determining the location, the probable location area of this destination is large and geometrically defined by an ellipse cylinder, ie by a cylinder with an elliptical base area (FIG. Fig. 7 ). The ignition location of the defense ammunition body 3 resulting from the ignition point is determined taking into account the following aspects:

• On the one hand, the distance to the target 4 should be as small as possible, because the number of effective splitters decreases due to the air resistance with increasing distance from the ignition location.
• On the other hand, something should be shot past the target 4, since the largest numbers of fragments occur in the edge region of the fragment cone.

It is advantageous if a weighted average is used from both calculated ignition times, so that the probability of destruction is maximized. The weighting factors may depend on the caliber and type of assault ammunition detected by the locator, and may be determined by simulation or experimentation.

The exact observance of the ignition time T _Z has a high prey and their accuracy must be in the millisecond range, since otherwise the ignition would take place too far in front of or behind the target 4.

A significant quantity is first the scattering of ignition time itself, i. with which inaccuracy ignites the igniter 13 at the set ignition timing. An igniter 13 is used, which has a scattering of the tempier time of less than 2 ms.

The determination of the ignition timing T _Z takes place via the determination of the ignition interval. This is explained by an ammunition requirement calculation. By means of the munition requirement calculation it can be determined how many defense ammunition bodies 3 must be fired in order to effectively combat the attack ammunition 4 for a given confidence level.

The ammunition needs calculation is based on known statistical principles and indicates the average amount of ammunition required to completely destroy the target. According to the exponential law of destruction, this depends on the likelihood of a splitter p _k and the number of effective splinters against the target area N _w .

For the calculation of the probability of launches of N _w effective splitters against the target area, the essential assumption is made that, as in Fig. 6 sketched, the base of the fragment cone A _{E should be} exactly as large as the radar CEP area A _CEP , in which with the specified probability (eg, P = 50%) of the attack ammunition 4 is located.

The firing probability p _{k of} a single splitter results from the multiplication of the hit probability p _H with the destruction probability p _{K l H.} The hit probability _PH indicates in the case of frontal combat the probability to meet on the one hand the circular target surface and on the other hand the attack ammunition 4 in the longitudinal direction. The destruction probability p _{K l H} depends on the ratio of the energy of the defense ammunition body 3 to the minimum energy for penetrating the shell of the attack ammunition 4 and increases exponentially with it.

Measurement errors of the sensors of the measuring and locating devices 5, 10 and 12 in azimuth, elevation and distance increase the probable whereabouts of the assault ammunition 4 to be controlled and the radar CEP area, so that the demand for ammunition increases with inaccurate sensors. In addition, there are variations in the Shot development, the muzzle velocity of the defense ammunition body 3 and the ignition time for the initiation of the projectile and the subsequent splinter cone development. Added to this is the ballistic scattering of the ammunition 3 and the weapon 2. This affects the probability of hit and thus the need for ammunition. Therefore, in the context of the desired ammunition requirement for a defined confidence level, the error budget, which characterizes the sum of all errors in the system that must not be exceeded, is set for the overall system.

In the first step of the practical implementation, depending on the selected radar device 5, the area normal to the radar beam in which the assault ammunition 4 is located with the probability P is calculated. This area should correspond to the base area of the fragment cone A _E , so that as far as possible at least one splinter of all effective fragments can hit the target area A _T. This target area A _T is located somewhere in A _CEP with probability P and is thus a subarea of A _CEP .

With the surface A _E can then be the firing interval h _K , which corresponds to the splitter cone height, determine, to first estimate the opening angle of the fragment cone β _max . This serves - with the path velocity of the defense ammunition body 3 in the predicted area of control - as an input for the calculation of the fragment cone from the fragmentation distributions determined experimentally in the forecourt. With the now determined splitter cone opening angle β _max , it is now possible to calculate an improved ignition interval and thus the splinter cone. With the knowledge of the measured reference time T _M, the ignition time T _{Z is} determined by the ignition interval.

The total number of effective splinters, the opening angle and the web speed in the combat location are used with the data given above as an input parameter for the previously described ballistic probability calculation to calculate the amount of munitions N _S.

This ammunition requirement applies accordingly Fig. 7 strictly speaking, only for the base area of the ellipse cylinder facing the ignition location. If the assault ammunition 4 actually stops, for example, in the rear region of the ellipse cylinder, the fragment density is significantly lower and the fragmentation speed is reduced due to the longer flight path. This reduces the number of effective fragments per unit area and increases the need for ammunition. By a more accurate distance measurement, which can be performed by a further sensor, not shown, the length of the ellipse cylinder can be significantly reduced, so that the demand for ammunition in the entire ellipse cylinder is on the order of magnitude, as the closest to the ignition base.

To IX. Remote transmission of the ignition timing T _Z to the ignition control unit 9, (alternatively: direct remote release of the igniter 13)

The determined ignition timing T _Z is transmitted via the configured as a radio unit signal transmission unit 7 as coded Tempiersignale by radio to the configured as a radio unit signal receiving unit 8. The signal receiving unit 8 forwards the signals to the ignition control unit 9, in which the new ignition timing is stored. Furthermore, via the two radio units 7 and 8, the correct reception the ignition timing T _Z to the fire control computer confirmed. If not confirmed, the ignition timing is recalculated and transmitted to the defense ammunition body 3.

In another embodiment, by means of coded remote control signals for the determined ignition timing T _Z, the igniter 13 is remotely tripped via the two radio units 7 and 8 and the ignition control unit 9 immediately after the correct reception. With a suitable choice of carrier frequency (eg 520 kHz), the entire code can be sent within 100 microseconds, so that the transmission time T _Ü practically coincides with the ignition timing. By using a direct remote release, the determination of the optimum ignition timing can advantageously be delayed as long as possible, so that a more accurate determination of the trajectories is possible.

Increased security can be achieved by encoding the tempier signals or remote control signals. The code is evaluated by the ignition control unit to determine the correct reception of the remote control signals. Only at the end of the review of the code, which must match the code known to the ignition control unit, the Tempierungsvorgabe is implemented or initiated directly the ignition.

In another embodiment, not shown, the defense ammunition body additionally has a proximity fuse. This initiates the ignition when the defense ammunition body 3 is at an adjustable distance to the attack ammunition 4. The advantage here is that in the case in which the determined ignition timing was actually too late, there is a certain chance that the Defense ammunition is previously initiated by means of the proximity fuse.

In one embodiment, not shown, the defense ammunition body as a detonator only a proximity fuse, but no radio unit 8. The proximity fuse triggers the ignition when the defense ammunition body 3 is at an adjustable distance to the attack ammunition 4, for example at a distance of 1 m. Thus, in this embodiment, the method steps VII to IX from Fig. 2 not done.

To X. Ignition of the explosive charge 14, formation of the fragment cone:

After the ignition of the explosive charge 14, the splinter cone forms. If the attack ammunition 4 was not successfully fought, another defensive ammunition body 3 is fired with a new Feuerleitlösung. In an advantageous embodiment, however, according to the determined need for ammunition, several defense ammunition bodies 3 are fired directly one after the other from one or more weapons 2, without waiting for a response to a successful combat.

The following results of an ammunition requirement calculations show that with the radar system MWRL-SWK selected in the exemplary embodiment shot numbers N _S <10 with 155 mm projectiles can be implemented as defensive ammunition bodies. When fighting an 82 mm throw grenade as an attack ammunition, the 155 mm bullet is well suited. Here, among other things, the large number of effective splitter N _{f; ges} = 7857 in conjunction with a large splitter cone opening angle β _max = 79.5 ° is responsible. The Fig. 8 shows a chart for ammunition needs for successful diversification at a confidence level (CL) of 50% and the Fig. 9 shows for different spreads a chart of ammunition needs for successful combat at a confidence level of 9%. Here are the two Fig. 8 and Fig. 9 plotted on the abscissa the standard deviation of azimuth and elevation of the radar, which are assumed to be the same. The ordinate plots the required integer shot numbers for given values of CL. It is noteworthy that even with a destruction probability of 99%, the munitions requirement of 155 mm bullets with the assumptions made is a maximum of four shots and thus clearly in the single-digit range.

Claims (15)

1. Method for protecting against airborne offensive ammunition elements (4), wherein

   i. the offensive ammunition element (4) is located by means of at least one position-finding device (5, 12);

   ii. the trajectory of the offensive ammunition element (4) is computed iteratively, whereby for the purpose of computing the trajectory of the offensive ammunition element (4) the ballistic coefficient c of the offensive ammunition element (4) is ascertained, in mass-related manner, from the difference of two kinetic energies of the offensive ammunition element (4) at two locations and from the distance between these two locations;

   iii. a firing-control solution for firing a defensive ammunition element (3) with fragmentation effect is ascertained;

   iv. the defensive ammunition element (3) is fired by means of a large-calibre weapon (2), in particular a weapon with a calibre of at least 76 mm, and

   v. after firing, the defensive ammunition element (3) is capable of having its fuse set and/or is capable of being detonated remotely, and, after firing, detonates or is detonated remotely at a detonation-time T_Z.
2. Method according to Claim 1, characterised in that the velocity v_M of the defensive ammunition element (3) at a defined time T_M is ascertained by means of a measuring device, whereby in particular the measuring device (10) is capable of being aimed and, at the time of firing of the defensive ammunition element (3), is aimed in the direction of the firing direction.
3. Method according to one of the preceding claims, characterised in that by way of detonation-time T_Z the time is ascertained at which a high, in particular the greatest, probability of a successful engagement of the offensive ammunition element (4) obtains, said probability resulting, in particular, from the product of the probability of a hit, which specifies whether a fragment hits the offensive ammunition element, and the probability of destruction, which specifies whether this fragment is capable of destroying the casing of the offensive ammunition element (4).
4. Method according to Claim 3, characterised in that in connection with the determination of the detonation-time T_Z one or more parameters are taken into account, selected from the group consisting of:

   a) measuring inaccuracies of the measuring device (10), in particular in connection with the determination of time, velocity, azimuth, elevation and/or range;

   b) measuring inaccuracies of the position-finding device (5, 12), in particular in connection with the determination of time, velocity, azimuth, elevation and/or range;

   c) type of the offensive ammunition element (4), in particular the hardness thereof;

   d) type of the defensive ammunition element (3), in particular the properties thereof such as fragmentation matrix, fragmentation-cone formative time, inaccuracies of the fuse-setting time;

   e) shot-development time of the defensive ammunition element (3);

   f) ballistic scattering.
5. Method according to one of the preceding claims, characterised in that the detonation-time T_Z is ascertained by an analytical method.
6. Method for protecting against airborne offensive ammunition elements (4), wherein

   i. the offensive ammunition element (4) is located by means of at least one position-finding device (5, 12),

   ii. the trajectory of the offensive ammunition element (4) is computed iteratively, whereby for the purpose of computing the trajectory of the offensive ammunition element (4) the ballistic coefficient c of the offensive ammunition element (4) is ascertained, in mass-related manner, from the difference of two kinetic energies of the offensive ammunition element (4) at two locations and from the distance between these two locations,

   iii. a firing-control solution for firing a defensive ammunition element (3) with fragmentation effect is ascertained,

   iv. the defensive ammunition element (3) is fired by means of a large-calibre weapon (2), in particular a weapon with a calibre of at least 76 mm, and

   v. the detonation of the defensive ammunition element (3) is initiated by a proximity fuse arranged in the defensive ammunition element.
7. Method according to one of the preceding claims, characterised in that for the purpose of ascertaining the type of the offensive ammunition element (4) the ballistic coefficient c of the offensive ammunition element (4) is ascertained.
8. Method according to one of the preceding claims, characterised in that the ballistic coefficient c is ascertained with the aid of the determination of the drag force of the offensive ammunition element (4).
9. Method according to one of the preceding claims, characterised in that for the purpose of ascertaining a kinetic energy two measuring points are recorded by means of the position-finding device (5, 12), from which measuring points the velocity of the offensive ammunition element (4) is ascertained.
10. Method according to one of the preceding claims, characterised in that the probable ammunition demand for defensive ammunition elements (3), in particular the number of defensive ammunition elements (3) to be fired, is ascertained after the locating of the offensive ammunition elements (4).
11. Method according to Claim 10, characterised in that the defensive ammunition elements (3) are fired in accordance with the ascertained ammunition demand unless the successful engagement of the offensive ammunition element (4) is detected.
12. Method according to Claim 10 or 11, characterised in that in connection with the ascertainment of the ammunition demand, in particular of the number of defensive ammunition elements (3) to be fired, one or more parameters are taken into account, selected from the group consisting of:

    a) measuring inaccuracies of the measuring device (10), in particular in connection with the determination of time, velocity, azimuth, elevation and/or range;

    b) measuring inaccuracies of the position-finding device (5, 12), in particular in connection with the determination of time, velocity, azimuth, elevation and/or range;

    c) type of the offensive ammunition element (4), in particular the hardness thereof;

    d) type of the defensive ammunition element (3), in particular the properties thereof such as fragmentation matrix, fragmentationcone formative time, inaccuracies of the fuse-setting time;

    e) shot-development time of the defensive ammunition element (3);

    f) ballistic scattering.
13. Method according to one of the preceding claims, characterised in that, prior to firing, the fuse of the defensive ammunition element (3) is preset to a time T_pre that lies temporally ahead of the time T_B predicted by the fire-control solution ascertained prior to firing, at which the defensive ammunition element (3) strikes the ground if it is not detonated, and that lies, in particular, temporally after the time T_A that is determined by the detonation-time T_Z of the defensive ammunition element (3) predicted by the fire-control solution ascertained prior to firing.
14. Method according to one of the preceding claims, characterised in that a warning is given for the region of the point of impact on the ground ascertained by the ascertained trajectory of the offensive ammunition element (4).
15. Method according to one of the preceding claims, characterised in that for the purpose of computing the trajectory of the offensive ammunition element (4) the equations of motion of the exterior ballistics are solved.

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