EP0802391B1 - Method of identifying a corrected disintegration time of a programmable and frangible projectile - Google Patents

Abstract

The disaggregation time determination involves calculating using an impact distance to a target determined by sensor data. A given disaggregation distance is maintained constant by correcting a disaggregation time. The correction is performed using the equation: Tz(Vm) = Tz + K*(Vm-Vov) Tz(Vm) is a corrected disaggregation time. Tz is the disaggregation time. K is a correction factor. Vm is a measured projectile velocity. Vov is a lead velocity of a projectile. The correction factor is determined starting from a flying time (t*) over a shortest distance between a projectile and a target.

Description

The invention relates to a method for determining a corrected disassembly time one of a programmable disassembled from a gun barrel Projectile according to the preamble of the only claim.

With the European patent application 0 300 255 a device has become known which has a measuring device for the projectile velocity arranged at the mouth of a gun barrel. The measuring device consists of two ring coils arranged at a certain distance from one another. When a bullet passes through the two ring coils, a pulse is generated in short succession in each ring coil due to the change in magnetic flux that occurs. The pulses are fed to evaluation electronics, in which the projectile speed is calculated from the time interval between the pulses and the distance between the ring coils. In the direction of movement of the projectile, a transmitting coil is arranged behind the measuring device for the speed, which co-operates with a receiving coil provided in the projectile. The receiving coil is connected to a counter via a high-pass filter, which is connected on the output side to a timer. A disassembly time is formed from the calculated bullet speed and a target distance to a target object, which is transmitted inductively to the bullet immediately after the measuring device has flown through. With this disassembly time, the time fuse is set so that the projectile can be disassembled in the area of the target object.

If projectiles with sub-projectiles are used (ammunition with primary and secondary ballistics), an attacking target can be destroyed by multiple hits, as is known, for example, from a publication OC 2052 d 94 from the company Oerlikon-Contraves, Zurich, if, after the sub-projectiles have been ejected, Time of disassembly the expected area of the target is occupied by a cloud formed by the subprojectiles. When dismantling such a projectile, the part carrying the subprojectiles is separated and torn open at predetermined breaking points. The ejected sub-projectiles describe a swirl-stabilized trajectory caused by the rotation of the projectile and lie evenly distributed on approximately semicircular curves of circular areas of a cone, so that a good chance of hitting can be achieved.

In the device described above, scattering in the disassembly distance, which, for example, by scattering the bullet speed and / or use not updated values are caused, not always a good meeting or Probability of being shot down. With larger disassembly distances the circular area would probably be larger, but the density of the subprojectiles would be smaller. The reverse occurs with smaller disassembly distances: the density of the subprojectiles would be larger, but the circular area would be smaller.

The invention has for its object to propose a method according to the preamble, by means of which an optimal while avoiding the disadvantages mentioned above Hit or shot probability is achievable.

This object is achieved by the invention specified in the single patent claim. Here a given optimal decomposition distance between a decomposition point of the Floor and a meeting point of the target by correcting the disassembly time of the Projectile kept constant. The correction takes place at the disassembly time correction factor multiplied by a speed difference is added. The speed difference is the difference between the current measured bullet speed and a lead rate of the projectile, the Lead speed from the mean of a number of previous, successive ones Floor speeds is calculated.

The advantages achieved with the invention can be seen in the fact that a given disassembly distance is independent of the current measured bullet speed, so that a permanent optimal hit or shot probability is achieved can. The proposed correction factor for correcting the disassembly time is based only on the relative velocity of the bullet-target and a derivation of the ballistics at the meeting point.

Fig.1

eine schematische Darstellung eines Waffensteuerungs-Systems mit der er findungsgemässen Vorrichtung,

Fig.2

einen Längsschnitt durch eine Mess- und Programmiervorrichtung,

Fig.3

ein Diagramm der Verteilung von Subprojektilen in Abhängigkeit von der Zer legungsdistanz, und

Fig.4

eine andere Darstellung des Waffensteuerungs-Systems gemäss Fig.1.

The invention is explained in more detail below using an exemplary embodiment in conjunction with the drawing. Show it.

Fig. 1

1 shows a schematic illustration of a weapon control system with the device according to the invention,

Fig. 2

a longitudinal section through a measuring and programming device,

Fig. 3

a diagram of the distribution of subprojectiles depending on the decomposition distance, and

Fig. 4

another representation of the weapon control system according to Fig.1 .

In Figure 1, 1 denotes a fire control and 2 a gun. The fire control system 1 consists of a search sensor 3 for the detection of a target 4 , a follow-up sensor 5 connected to the search sensor 3 for target detection, 3-D target tracking and 3-D target measurement, and a fire control computer 6 . The fire control computer 6 has at least one main filter 7 , a lead computing unit 9 and a correction computing unit 12 . The main filter 7 is connected on the input side to the follow sensor 5 and on the output side to the lead computing unit 9 , the main filter 7 receiving the 3-D target data received from the follow sensor 5 in the form of estimated target data 2 such as position, speed, acceleration, etc. forward the lead computing unit 9 , which is connected on the output side to the correction computing unit. Meteorological data can be supplied to the lead computing unit 9 via a further input Me. The meaning of the designations on the individual connections or connections is explained in more detail below on the basis of the functional description.

A computer of the gun 2 has an evaluation circuit 10 and an update computing unit 11 . The evaluation circuit 10 is connected on the input side to a measuring device 14 for the projectile speed, which is arranged at the mouth of a gun barrel 13 and is described in greater detail below with reference to FIG . 2 , and is connected on the output side to the lead computing unit 9 and the update computing unit 11 . The update computing unit 11 is connected on the input side to the reserve and correction computing unit 9, 12 and is connected on the output side to a programming part integrated in the measuring device 14 . The correction arithmetic unit 12 is connected on the input side to the lead arithmetic unit 9 and on the output side to the update arithmetic unit 11 . A gun servo 15 and a triggering device 16 responding to a fire command are also connected to the lead computing unit 9 . The connections between the fire control 1 and the gun 2 are combined to form a data transmission, which is designated by 17 . The meaning of the designations on the individual connections between the computing units 10, 11, 12 and between the fire control system 1 and the gun 2 is explained in more detail below on the basis of the functional description. 18 and 18 ' designate a floor which is shown during a programming phase ( 18 ) and at the time of disassembly ( 18' ). The projectile 18 is a programmable projectile with primary and secondary ballistics, which is equipped with an ejection charge and a time fuse and is filled with sub-projectiles 19 .

According to FIG. 2 , a support tube 20 attached to the muzzle of the gun barrel 13 consists of three parts 21, 22, 23 . Between the first part 21 and the second or third part 22, 23 , ring coils 24, 25 are arranged for measuring the projectile speed. On the third part 23 — also called the programming part — a transmission coil 27 held in a coil body 26 is fastened. The type of attachment of the support tube 20 and the three parts 21, 22, 23 to each other is not shown and described. Lines 28, 29 are provided for supplying the ring coils. Soft iron bars 30 are arranged on the circumference of the support tube 20 for the purpose of shielding against magnetic fields which interfere with the measurement. The projectile 18 has a receiving coil 31 which is connected to a timer 34 via a filter 32 and a counter 33 . When the projectile 18 passes through the two ring coils 24 , 25, a pulse is generated in short succession in each ring coil. These pulses of the evaluation circuit 10 (Fig.1) are supplied, in which from the time interval of the pulses and a distance a between the toroid coils, the projectile velocity is calculated 24.25. Taking the projectile speed into account, a disassembly time is calculated, as described in more detail below, which is transmitted inductively in digital form to the receiving coil 31 when the projectile 18 passes through the transmitting coil 27 for the purpose of setting the counter 32 .

In Figure 3 , Pz denotes a point of disassembly of the projectile 18 . The ejected subprojectiles are, depending on the distance from the point of decomposition Pz, evenly distributed on approximately semicircular curves of (perspectively represented) circular areas F1, F2, F3, F4 of a cone C. On a first abscissa the distance from the point of decomposition Pz is plotted in meters m, while on a second abscissa II the area sizes of the areas F1, F2, F3, F4 are plotted in square meters m ² and their diameter in meters m. In the case of a characteristic projectile with, for example, 152 subprojectiles and an apex angle of the cone C of initially 10 °, the values plotted on the abscissa II are obtained as a function of the distance. The density of the subprojectiles on the circular areas F1, F2, F3, F4 decreases with increasing distance and is 64, 16, 7 and 4 subprojectiles per square meter with the selected ratios. Given a predetermined disassembly distance Dz on which the disassembly time is based, as described below, for example 20 m, in the assumed example a target area of 3.5 m in diameter would be occupied with 16 subprojectiles per square meter.

In FIG. 4 , 4 and 4 ' denote the target to be defended, which is shown in a hit or shoot position ( 4 ) and in a position ( 4' ) preceding the hit or shoot position.

The device described above works as follows:

The lead computation unit 9 calculates a target distance RT, a disassembly time Tz and a sub-projectile flight time ts from a predetermined disassembly distance Dz, a retention speed VOv and the target data Z, taking meteorological data into account for projectiles with primary and secondary ballistics. Here, Tz is the flight time of the projectile to the point of disassembly Pz and ts is the flight time of a subprojectile flying in the projectile direction from the point of disassembly Pz to the meeting point Pf ( Fig . 3,4 ).

The lead speed VOv is formed, for example, from the mean value of a number of measured projectile speeds Vm supplied via the data transmission 17 , which immediately precede the current measured projectile speed Vm.

The lead computing unit 9 also determines a gun angle a of the azimuth and a gun angle λ of the elevation. The quantities α, λ, Tz and VOv are fed to the correction computing unit 12 , which calculates a correction factor K as described in more detail below. The quantities α, λ, Tz, VOv and K are referred to as shooting elements of the meeting point and are fed to the gun computer via the data transmission 17 , the shooting elements α and λ being fed to the gun servo 15 and the shooting elements VOv, Tz and K of the update computing unit 11 be fed. If only Primärballistik is used, so instead of the disaggregation time Tz, the impact time Tf = Tz + ts transmitted (Fig.1, Fig.4) is.

The calculations described above are repeated in cycles, so that in the current clock i the newest data α, λ, Tz orTf, VOv and K for a certain period of validity is available.

Between the cycle values, the current (running) time (t) is interpolated or extrapolated.

beschrieben, wobei zusammen mit den Anfangsbedingungen

eine eindeutige ballistische Lösung

bestimmt wird. Im durch die Gleichungen Gl.1 und Gl.2 bestimmten System ist als Randbedingung die Treffbedingung

enthalten, wobei TG = TG(t_o ,ν _o (t_o )) ist, und wobei die Vorhalt-Grösse ν _o(t_o ) vom Geschoss nicht als Anfangsgeschwindigkeit angenommen wird. Mit

wird eine Komponente von ν _o (t_o ) in Rohrrichtung und mit ν (2) / o eine senkrecht dazu gerichtete Komponente definiert, so dass

ist, wobei

die Geschwindigkeit der Rohrmündung bedeutet und eine Vorhalt-Grösse ist, welche vom Geschoss tatsächlich eingehalten wird. Dagegen kann à priori keine Aussage über den Betrag der Komponente der Anfangsgeschwindigkeit des Geschosses in Rohrrichtung gemacht werden. Die Grösse ν o = ν o (t o ) : = ∥ν (1) o ∥ wird vom Geschoss in der Tat nicht genau angenommen. Der tatsächliche Betrag der Komponente der Anfangsgeschwindigkeit des Geschosses in Rohrrichtung wird mit Vm bezeichnet. Diese Grösse wird für jedes Geschoss an der Rohrmündung gemessen (Fig.1 und 2). Die effektive Anfangsgeschwindigkeit des Geschosses beträgt jetzt

Der Einfachheit halber kann die Abhängigkeit von der Anfangsgeschwindigkeit durch die Abhängigkeit vom Betrag der Komponente der Anfangsgeschwindigkeit in Rohrrichtung ersetzt werden, so dass

ist und sich die ballistische Lösung zu

ergibt. Mit der effektiven Anfangsgeschwindigkeit gemäss Gleichung Gl.5 ist die Lösung der Gleichungen Gl.1, Gl.2 von der Form

Ein Geschoss mit der durch

gegebenen Bahn wird das Ziel im allgemeinen nicht mehr treffen. Bei der Berechnung des Korrekturfaktors K wird daher von der durch die Definition

gegebenen Flugzeit t* des kleinsten Abstandes zwischen einem Geschoss und einem Ziel und der partiellen Ableitung nach der Flugzeit

ausgegangen und durch Einsetzen der Definition

die Gleichung Gl.6 vereinfacht. Durch differenzieren der Gleichung Gl.6 wird

gewonnen. Danach wird die als Randbedingung im System der Differentialgleichungen der Ballistik enthaltene Treffbedingung gemäss Gleichung Gl.3 unter Berücksichtigung der Definition für t* t*(ν o ) = TG

eingesetzt, wobei aus Gleichung Gl.7 für Vm=vo

folgt. Durch Einsetzen der Definition

wird Gleichung Gl.7.1 vereinfacht, wobei sich der Korrekturfaktor K zu K := D 1 t*(ν o ) = -〈ν rel (ν o ), ∂ P G ∂ νo 〉〈ν rel (ν o ), ν rel (ν o )〉 ergibt.The ballistics of a projectile is determined by a system of differential equations of the form

described, along with the initial conditions

a clear ballistic solution

is determined. In the system determined by equations Eq.1 and Eq.2, the meeting condition is the boundary condition

included, where TG = TG ( t _o , ν _o ( t _o )), and where the lead size ν _o ( t _o ) is not assumed to be the initial velocity by the projectile. With

becomes a component of ν _o ( t _o ) in the pipe direction and with ν (2) / o defines a perpendicular component, so that

is where

means the speed of the pipe mouth and is a reserve size which is actually maintained by the projectile. On the other hand, no statement can be made a priori about the amount of the component of the initial velocity of the projectile in the pipe direction. The size ν O = ν O ( t O ): = ∥ ν (1) O ∥ is in fact not exactly accepted by the projectile. The actual amount of the component of the initial velocity of the projectile in the pipe direction is referred to as Vm. This size is measured for each floor at the pipe mouth (Fig. 1 and 2). The effective initial velocity of the bullet is now

For the sake of simplicity, the dependency on the initial speed can be replaced by the dependence on the amount of the component of the initial speed in the pipe direction, so that

is and the ballistic solution too

results. With the effective starting speed according to equation Eq.5, the solution of equations Eq.1, Eq.2 is of the form

A bullet with the through

given the path, the target will generally no longer hit. When calculating the correction factor K is therefore by the definition

given flight time t * of the smallest distance between a floor and a target and the partial derivative after the flight time

assumed and by inserting the definition

simplified the equation Eq.6. By differentiating the equation Eq.6

won. Then the hit condition contained as a boundary condition in the system of the differential equations of ballistics according to equation Eq. 3 taking into account the definition for t * t * (ν O ) = TG

used, from equation Eq.7 for Vm = vo

follows. By inserting the definition

Equation Eq.7.1 is simplified, with the correction factor K increasing K : = D 1 t * (ν O ) = - 〈 ν rel (ν O ), ∂ P G ∂ νo 〉 〈 ν rel (ν O ), ν rel (ν O )〉 results.

ν

ein Vektor

∥ν∥

Norm des Vektors

〈 u , ν〉

Skalarprodukt

.

skalare oder Matrixmultiplikation

g := A

die Grösse g wird definiert als Ausdruck A

g = g(x ₁,...,x_n )

die Grösse g hängt ab von x₁,....,x_n

t ↦ g(t)

Zuordnung (t wird die Auswertung von g an der Stelle t zugeordnet)

g ˙

Ableitung von g nach der Zeit

D_ig(x ₁,...,x_n )

partielle Ableitung von g nach der i-ten Variablen

∂ / ∂t g(t,x ₁,...,x_n )

partielle Ableitung von g nach der Zeit t

inf _tM

Infimum der Menge M über alle t

p _G, ν _G, a _G

Position,Geschwindigkeit,Beschleunigung des Geschosses

p _Z, ν _Z, a _Z

Position,Geschwindigkeit,Beschleunigung des Zieles

p _rel ,ν _rel , a _rel

relative Position,Geschwindigkeit,Beschleunigung Geschoss-Ziel

Position der Rohrmündung

ν _o

Vorhalt-Anfangsgeschwindigkeit des Geschosses

ν _o

Betrag der Komponente der Vorhalt-Anfangsgeschwindigkeit des Geschosses in Rohrrichtung

ν _m

Betrag der Komponente der effektiven Anfangsgeschwindigkeit des Geschosses in Rohrrichtung

TG.

Vorhalt-Flugzeit des Geschosses

t*

Flugzeit des Geschosses

t_o

Zeitpunkt zu dem das Geschoss die Rohrmündung passiert.

The mathematical or physical notation used above means:

ν

a vector

∥ ν ∥

Norm of the vector

〈 u , ν 〉

Dot product

.

scalar or matrix multiplication

g : = A

size g is defined as expression A

g = g ( x ₁ , ..., x _n )

the size g depends on x ₁ , ...., x _n

t ↦ g ( t )

Assignment (t is assigned the evaluation of g at point t)

g ˙

Derivation of g after time

D _i g ( x ₁ , ..., x _n )

partial derivative of g after the i-th variable

∂ / ∂ t g ( t , x ₁ , ..., x _n )

partial derivative of g after time t

inf _t M

Infimum of the set M over all t

p _G , ν _G, a _G

Position, speed, acceleration of the projectile

p _Z , ν _Z , a _Z.

Position, speed, acceleration of the target

p _rel , ν _rel , a _rel

relative position, speed, acceleration floor-target

Position of the pipe mouth

ν _O

Lead initial speed of the projectile

ν _o

Amount of the component of the initial initial velocity of the projectile in the pipe direction

ν _m

Amount of the component of the effective initial velocity of the projectile in the pipe direction

TG .

Lead flight time of the projectile

t *

Flight time of the projectile

t _o

Time at which the bullet passes the muzzle.

The update arithmetic unit 11 calculates a corrected disassembly time Tz (Vm) from the correction factor K supplied by the correction arithmetic unit 12, the current measured projectile speed Vm supplied by the evaluation circuit 10 and the lead speed Vov supplied by the lead computing unit 9 the relationship Tz (Vm) = Tz ÷ K * (Vm-VOv).

The corrected decomposition time Tz (Vm) is interpolated or extrapolated depending on the validity for the current running time t. The disassembly time Tz (Vm, t) now calculated is supplied to the transmitter coil 27 of the programming part 23 of the measuring device 14 and, as already described above with reference to FIG. 2 , is transmitted inductively to a projectile 18 flying by.

With the correction of the disassembly time Tz, the disassembly distance Dz ( FIG. 3, 4 ) can be kept constant regardless of the variations in the projectile speed , and / or caused by the use of non-updated values, so that an optimal meeting or Probability of shooting can be achieved.

Claims (1)

1. Method for determining a corrected fragmentation time (Tz(Vm)) for a programmably fragmentable projectile (12) fired from a gun-barrel (13) with a view to maintaining constant a given fragmentation distance (Dz) between a point of fragmentation (Pz) of the projectile (12) and a point of collision (Pf) of the projectile (12) with a target travelling at speed, in which

   sensor data are measured from which a strike distance (RT) from the gun-barrel (13) to the target is computed,

   the velocity (Vm) of the fired projectile is measured at the muzzle of the gun-barrel (13), and

   determination of the corrected fragmentation time (Tz(Vm)) is based upon at least

   the said strike distance (RT),

   the said velocity (Vm) of the projectile (12), and

   the fragmentation distance (Dz),

   characterized in that

   a predicted velocity (VOv) of the projectile is also determined from the measured sensor data, and

   the corrected fragmentation time (Tz(Vm)) is determined from the originally defined fragmentation time (Tz) by the relation Tz(Vm) = Tz + K x (Vm - VOv) in which

   Tz(Vm)

   stands for the corrected fragmentation time,

   Tz

   is the originally defined fragmentation time,

   K

   is a correction factor,

   Vm

   is the presently measured muzzle velocity of the projectile and

   VOv

   is a predicted velocity of the projectile,

   where the correction factor (K), proceeding from the flight time (t*) of the shortest distance between a projectile and a target - given by the definition

   

   and the partial derivative with respect to flight time

   

   is found by the following calculation steps:

   simplifying Equation 6 by inserting the definitions

   

   

   

   differentiating Equation 6 with respect to the presently measured muzzle velocity, to give

   

   inserting a strike condition (Equation 3) included as a boundary condition in the system of differential equations of the ballistics, taking account of the definition for t* t*(ν o ) = TG

   

   so that Equation 7 yields, for v_m = v_o

   

   simplifying Equation 7.1 by insertion of the definition

   

   yielding the correction factor K := D 1 t*(ν o ) = - 〈ν rel (ν o ), ∂ P G ∂ν o 〉〈ν rel (ν o ), ν rel (ν o )〉 where

   p _G, ν _G, a _G

   stand for the position, velocity, acceleration of the projectile

   p _Z, ν _Z, a _Z

   the position, velocity, acceleration of the target

   p _rel, ν _rel, a _rel

   the relative position, velocity, acceleration of the projectile/target

   

   the position of the muzzle

   ν _o

   predicted initial velocity of the projectile

   ν _o

   the value of the predicted initial velocity component of the projectile in the direction of the barrel

   ν _m

   the value of the actual initial velocity component of the projectile in the direction of the barrel

   TG

   the predicted flight time of the projectile

   t*

   the flight time of the projectile

   t_o

   the instant at which the projectile passes through the muzzle of the barrel.

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