DE3404953A1 - Circuit arrangement for the contactless measurement of velocities in projectiles - Google Patents

Abstract

A microwave transmitter (1) mounted on the barrel muzzle simulates an electronic measuring base in such a manner that, in accordance with the Doppler principle, a rest signal (fA) is mixed with an acceleration signal (fD) in the projectile tip and from this the muzzle velocity of the projectile is produced. This value is given to a delayed fuse (2) as correction factor. <IMAGE>

Description

BROWN, BOVERI & CIE AKTIENGESELLSCHAFT Mannheim February 8, 1984

Mp. No. 513/84 ZPT / P3-NL / Bt

Circuit arrangement for non-contact measurement of

Bullet speeds

The invention relates to a circuit arrangement for the non-contact measurement of speeds Shot.

From the patent application P 34 04 011.0 it is known to increase the exit speed of projectiles from the tube determine. For this purpose, two concentric grooves are arranged as a measuring base within the tube. In the storey

spitze is a microwave transmitting and receiving device built-in. When the projectile flies past the grooves on the inside of the pipe, signals are generated that serve to determine the speed of the projectile. According to this recorded actual projectile velocity a time fuse in the projectile should be corrected. The disadvantage of this arrangement is that e.g. ring grooves have to be milled into the pipe or the pipe has to be mechanically processed.

A non-contact measurement of the

Bullet speed to correct setting values on electronic time fuses, in such a way that the speed detection does not have any additional components and devices on the weapon are required. This results in simple influencing of the timer in the Floor and processing of the measurement data.

A general data and energy transmission via microwaves is known from DE-PS 25 08 201. An arrangement for the transmission of data between a cannon and a projectile with subsequent correction of the projectile data is known from DE-OS 31 50 172.

It is therefore the object of the invention to provide a circuit arrangement that can be used with both normal caliber projectiles allow a quick detection of the speed in the barrel, which every constructive Eliminate effort on the pipe, e.g. also with concentric grooves on the inside of the pipe, and one

Correction of the timer located on the projectile 20

enables.

According to the invention, this is made possible by the features of the claims achieved.

The circuit arrangement according to the invention can advantageously be used for lower-caliber and normal-caliber projectiles in cannons, howitzers, rocket launchers, grenade launchers, mine launchers, mortars, etc. are used. By Gun barrels can be used with little construction effort

the highly accurate inventive speed measuring arrangement can be retrofitted. It only needs in the simplest way Way drilled a hole in the muzzle wall of the gun barrel to accommodate a microwave transmitter will. The circuit arrangement is also in one

possibly existing muzzle damper can be installed. Since the

Microwave transmitter advantageously a polarized wave field with only a single frequency component radiates, possible interference can be suppressed. The receiving antenna in the tip of the bullet is preferably designed as a conical dipole. the

The receiving antenna in the tip of the projectile is advantageously switched in such a way that the connection to the evaluation electronics can be switched off after leaving the gun barrel in order to prevent external influences. the Energy for the voltage supply of the circuit arrangement according to the invention is advantageously used taken from the microwave field of the transmitter on the gun barrel. Further advantages are from the description below evident.

An embodiment of the circuit arrangement according to the invention is shown below with reference to the drawing explained in more detail.

At the muzzle of a gun barrel is only an andeu-20

partially drawn microwave transmitter 1 arranged. At the top of a projectile that is still in the barrel is a time igniter 2 and the inventive receiving circuit for the microwave signals from the Transmitter 1 housed. The receiving circuit evaluates the signals from the transmitter 1 and corrects the setting values of the time fuse 2. The indicated transmitter 1 at the muzzle of the gun barrel is structurally of this type designed so that it radiates into the gun barrel.

The circuit arrangement according to the invention acts in the idle state, i.e. after loading the gun, in such a way that that a presetting of the timer 2 is made by the microwave transmitter 1. To this end

The transmitter 1 beams into the gun barrel and activates 35

the time fuse 2 via a data receiver 3 with data

about the probable destination. With this presetting, the timer or the data receiver 3 Also supplied with voltage via the microwaves from the transmitter 1. Of course, one is also conceivable

own voltage source within the projectile head. 5

Via the microwave transmitter 1 attached to the pipe mouth, an indicated receiving device 4 is activated the projectile tip 1 preferably transmit an unmodulated wave with a constant frequency. This signal will out via a closed switch 5a to a PLL circuit 6 (PLL = phase locked loop = on through Phase control synchronized resonant circuit). In the PLL circuit 6, an oscillator 7 is included, the is synchronized to the frequency fß which the micro-

wave transmitter 1 emits in the idle state (after inserting the projectile into the gun barrel). The exit of the PLL circuit 6 or the oscillator 7 with the initial frequency fA is fed to a mixer 8.

The second input of the mixer 8 is also connected to the receiving antenna 4 via a switch 5b. in the In the idle state, the antenna 4 in the tip of the projectile receives the initial frequency fb and guides it to the

Mixer 8. If the projectile moves towards the muzzle 25

or the microwave transmitter to, is according to the known

Doppler principle receive a higher frequency fE, which is dependent on the speed, and which is fed to the second input of the mixer 8 via the switch 5b.
30th

The switch 5b is open in the idle state and the switch 5a is closed. Only hinted at in Acceleration sensor 5c built into the projectile tip

a 35

Output signal that opens the switch 5a and the

Switch 5b closes. The switches 5a and 5b therefore work alternately as a function of the acceleration sensor 5c.

When the projectile is moving, mixer 8 is

times the stored rest signal fA ^{from the} synchronized oscillator 7 and once the received signal fg. In the mixer 8, the Doppler frequency fD is formed from these two signals f ^ and f £, which represents a direct measure of the speed (f _D = fε - f _A ).

The mixer 8 is followed by a zero detector 9, the beginning and end of the oscillations of the Doppler frequency fn recognizes. In the gun barrel, through

Various influences, short-term fluctuations in the speed of the projectile occur, which affect the measurement result can falsify. This can be prevented in an advantageous manner that the zero detector 9 a Frequency divider not shown in the drawing is switched on. The zero detector 9 has an output for start impulses and an output for stop impulses. The start pulses are fed to an input of a counter 11 via an AND element 10, while the stop pulses ge-25 directly to another input of the counter 11

are attached. The counter 11 is controlled by the oscillator 7 clocked, the frequency of the oscillator 7 being divided down via a divider 12. It is also conceivable a clock supply of the counter 11 via a single one

Oscillator. In this case, the divider 12 can then be omitted. 30th

The acceleration sensor 5c acts via a timing element on the second input of the AND element 10. The timing element 13 is set so that just at the point in time when the projectile a certain distance has arrived in front of the muzzle, the acceleration

sensor sends a signal to AND gate 10. As a result, the AND element 10 is continuously switched and gives the Start pulse from zero detector 9 to counter 11.

At the output of the counter 11, which is led to the timer 2, there are pulses that are a direct measure for the muzzle velocity of the projectile. This value is used as a correction input for the timer 2.

One embodiment of the circuit arrangement according to the invention is used for presetting the timer (in modules 3 and 2) and the correction circuit each use its own microwave transmitter. Included

are both microwave transmitters at the mouth of the 15th

Gun barrel attached.

The receiving antenna 4 with the PLL circuit 6 and the Changeover switches 5a, 5b can advantageously be on a common insulating support using stripline technology be accommodated.

In a further embodiment, a microwave transmitter (not shown) can be connected to the counter 11, which sends the measurement result back to the gun barrel. Here it can then be used for further use by a fire control computer can be used.

It is also conceivable that a microwave transmitter attached to the time igniter 2 could result in the presetting ⁶

ment from the data receiver 3 is sent back to the gun barrel or the fire control computer.

Claims (5)

^{513/84 7} 3404353 Expectations Circuit arrangement for the non-contact measurement of speeds in projectiles, characterized in that that a microwave transmitter (1) is attached to the muzzle of a gun, that the microwave transmitter (1) provides information on a data receiver (3) for presetting a time igniter (2) transmits that the microwave transmitter (1) via a changeover switch (5a, 5b) controls either a PLL circuit (6) or a mixer (8), that the output of the PLL circuit (6) is also fed to the mixer (8), that the output of the mixer (8) on a NuIl-De-20 tektor (9) leads, that the zero detector (9) supplies start and stop pulses for a downstream counter (11), that the counter (11) via a divider (12) clock pulses from the oscillator (7) of the PLL circuit (6) receives, that the counter (11) from an accelerometer (5c) is controlled with a time delay (13), that in front of the counter (11) an AND element (10) is provided is switched, which is influenced once by the accelerometer (5c) and once by the zero detector (9), and
that the output of the counter (11) correction pulses switches to the timer (2). 35 2. Circuit arrangement according to claim 1, characterized in that the changeover switch (5a, 5b) through the accelerometer (5c) can be controlled. 3. Circuit arrangement according to claim 1, characterized in that for the presetting of the timer and the speed measurement separate microwave transmitters can be used. 4. Circuit arrangement according to claim 1, characterized in that the counter (11) has its own The oscillator is switched on as a clock generator. 5. Circuit arrangement according to claim 1, characterized characterized in that the counter (11) has a microwave 15 transmitter is switched on, which transmits the measurement result from the counter to a fire control center on the gun.