DE3904685A1 - Method for determining the detonation point of a projectile fired from a tube weapon, and a circuit arrangement for carrying out the method - Google Patents

Abstract

A method for determining the detonation point of a projectile fired from a tube weapon uses two transmission frequencies which are emitted from a base station positioned close to the tube weapon. These two transmission frequencies produce received frequencies in the projectile, which received frequencies differ from the transmission frequencies as a result of the Doppler influence. The low-frequency mixing product (difference frequency) between the two received frequencies is formed and, after this, it is once again mixed with the oscillator located in the projectile, so that an operating frequency is produced from it which, after further processing and integration, produces the distance travelled by the projectile. On reaching a predetermined distance value, a detonation pulse is emitted. <IMAGE>

Description

The invention relates to a method according to the preamble of claim 1 and a circuit arrangement for implementation of the procedure.

It is known to be the firing point of a barrel weapon fired projectile with the help of the Doppler effect determine. For this purpose, one from one of the barrel weapon is assigned Transmitting a microwave radiation certain frequency forwarded to the floor and that of Storey received frequency with one by one inside of the projectile located oscillator Frequency compared. If the frequency of the gun assigned oscillator is the same as that on the floor located oscillator generated frequency, then is the difference frequency determined on the floor Doppler frequency, from which then the one covered by the projectile Way can be determined. But since the floor oscillator  generated frequency for example Launch due to high acceleration forces or can change for other reasons, you get one Doppler frequency error and thus also an error with the calculation of the speed and in the end an error in the calculation or determination of the path covered by the floor.

Circuit arrangements with which the change in the floor oscillator frequency can be compensated for known, e.g. B. from DE-P 33 08 859.4, DE-P 36 26 023.1 and DE-P 37 34 490.6.

However, the known methods require a very high one Circuit effort, especially in tanks. Besides, will a certain time is required for the control process, the lost for the actual task of determining the path goes. This increases the minimum distance that can be achieved; for shorter distances between Gun and firing point can be the known methods not be used.

The object of the invention is a method of the beginning to create the type mentioned, even at shorter distances applicable between the barrel weapon and the ignition point is and also the circuitry is reduced. A circuit arrangement is also intended be specified for carrying out the method.

This object is achieved by the characterizing Features of claim 1.

So if two signals of the frequencies f _{S 1} or f _{S 2 are} emitted by the tank, both are subject to the Doppler shift.

Mixing the frequencies received by the floor in the floor creates, among other things, a mixed frequency f _M according to the formula:

f _M = | f _{E 1} - f _{E 2} |
= | (f _{S 1} - f _{S 2} ) · (1 - v / c) |
= | Δ f _S | · (1 - v / c) .

Here are:
f _{E 1} and f _{E 2} the frequencies received by the projectile and the frequencies emitted by the tank
frequencies corresponding to f _{S 1} and f _{S 2}
Δ f _S the difference between the two transmission frequencies (= f _{S 1} - f _{S 2} )
v = bullet velocity
c = propagation speed of electromagnetic waves.

It is important to keep this difference frequency Δ f _S as highly stable as possible in the tank by means of suitable stabilization methods, for example using a frequency control loop.

The resulting mixed frequency f _M is a low frequency, because Δ f _{S is} typically in the range around 10. . . 100 MHz and v / c is very small. Because the frequency Δ f _{S is} relatively low, it can be produced on the floor in a highly stable manner by an inexpensive, bulletproof crystal oscillator.

If the frequency f _{M is} now mixed with the frequency Δ f _S generated in the projectile, then a working frequency arises

f _A = f _S Δ · v / c.

This working frequency is directly proportional to the bullet speed, and it can be integrated through integration Statement about the floor path covered determined will. Then if the desired, previously set A setpoint value is reached, an ignition signal is given so that the projectile detonates.

The particular advantage of this method according to the invention is that you have a highly accurate, bulletproof Microwave oscillator as a reference source in the floor is not more, you need a relatively inexpensive, easy-to-implement bulletproof crystal oscillator with which you can use the comparison signal within of the projectile can produce highly stable.

Based on the drawing, in which an embodiment of the Invention is shown, should further advantageous embodiments and improvements of the invention explained in more detail and be described.

It shows

Fig. 1 is a schematic representation of a known circuit arrangement and

Fig. 2 is a schematic representation of a circuit arrangement according to the invention.

In Fig. 1, 10 denotes a barrel weapon and 11 a projectile. The projectile moves away from the barrel weapon 10 at the projectile speed v after the launch.

From the barrel weapon 10 or from a transmitter with an antenna 12 , the transmitter not shown, a signal with the frequency f _{S is} emitted, which is received by an antenna 13 within the floor 11 . The reception frequency is f _E.

This reception frequency is mixed in a mixer 14 with a frequency f _LO generated in a projectile oscillator 15 and the mixing frequency f _M is obtained via a filter device 16 . The following applies:

f _LO = f _S

if one assumes that the frequency of the oscillator 15 does not change.

The reception frequency is calculated as follows:

f _E = f _S (1- v / c) = f _S - f _D

in which

f _D = f _S · v / c

wherein

f _D the Doppler frequency,
v the velocity of the projectile and
c is the propagation speed of electromagnetic waves.

The mixing frequency f _M results from mixing as follows:

f _M = | f _E - f _LO |
= | (f _S - f _LO ) - f _S · v / c |
F = _S · v / c

This mixed frequency f _M is therefore directly proportional to the speed v and from this the speed v of the projectile and thus the distance traveled can then be determined by further processing.

This method described here does not work if the frequency f _{LO changes} within the floor. Such changes can result, for example, from aging or from the accelerating forces at launch.

According to the invention, a circuit arrangement according to FIG. 2 is used.

Inside the tank 20, shown in broken lines, there is an antenna 21 , via which two signals with the frequencies f _{S 1} and f _{S 2} can be emitted, the frequency spacing | f _{S 1} - f _{S 2} | = Δ f _S. These two signals are received on the floor 22 by means of an antenna 23 ; they arrive there with the frequency f _{E 1} and f _{E 2} . The input frequencies f _{E 1} and f _{E 2} are fed to a mixer 24 and a filter 25 , and the mixing frequency f _{M is present} at the output of the filter. In the floor 22 there is an oscillator 26 which generates the frequency f _LO . The oscillator 26 is connected to a further mixer 27 , in which the frequency f _M and the frequency f _{LO are} mixed, whereby an operating frequency f _{A is} generated, which can then be processed further. The oscillator 26 , whose frequency f _{LO is} equal to the difference frequency Δ f _LS , is a highly stable crystal oscillator and the difference frequency is in the range around 10. . . 100 MHz, so that the oscillator 26 is an inexpensive low-frequency oscillator.

The reception frequencies result from the transmission frequencies f _{S 1} and f _{S 2} as follows:

f _{E 1} = f _{S 1} · (1 - v / c)

f _{E 2} = f _{S 2} · (1 - v / c) .

Mixing the two reception frequencies in the floor or there in the mixer 24 results in the mixing frequency f _M :

f _M = (f _{E 1} - f _{E 2} )
= (f _{S 1} - f _{S 2} ) · (1 - v / c)
= Δ f _S (1 - v / c) .

After the high-frequency components have been separated off by the low-pass filter 25 , the frequency f _M in the second mixer 27 is mixed with the frequency f _{LO of} the highly stable, wear-resistant quartz oscillator 26 . If the difference between the microwave oscillators in the tank Δ f _S corresponds to the frequency of the quartz oscillator f _LO , the mixing frequency f _A = Δ f _S · v / c and thus the projectile velocity is proportional, so that the distance traveled can be determined by integration.

Claims (2)

1. A method for determining the firing point of a projectile fired from a tube weapon (base station) with the aid of a micro- or millimeter-wave radiation emitted by the tube weapon using the Doppler effect, characterized in that the micro- or millimeter-wave radiation has two around 10. . . 100 MHz differential frequency Δ f _{S has} different frequencies (f _{S 1} and f _{S 2} ) that are received on the floor and to form a mixed frequency f _M = Δ f _S (1 - v / c) in which:
v = bullet speed
c = propagation speed of electromagnetic waves
are mixed and that this mixing frequency f _M in the floor is in turn mixed with the frequency f _LO = Δ fs generated by means of a floor oscillator arranged in the floor to form a working frequency directly proportional to the floor speed f _A = Δ f _S · v / c from that of Projectile distance covered is determined, and that an ignition signal is given when the predetermined distance is reached. 2. Circuit arrangement for performing the method according to claim 1, characterized in that in the base station two base oscillators for generating the microwave frequencies f _{S 1} and f _{S 2} , the highly stable difference Δ f _S in the range around 10. . . 100 MHz, it is provided that a first mixer, the output of which is connected via a filter to a second mixer, is provided in the floor, a floor oscillator for generating the frequency f _LO = Δ f _S , the output of which is also connected to the second mixer and that the output of the second mixer is connected via a filter to an integrator for determining the distance traveled by the projectile.