DE10346951B4 - Method and device for discriminating against an environmental disturbance such as camouflage fog, smoke or the like - Google Patents

Abstract

Method for discriminating an environmental disturbance, such as camouflage fog, smoke or the like, along the trajectory of a missile having an optronic detonator and a sensor base (12) with a measuring unit (14), characterized in that the measuring unit (14) determines the pulse width of reflex pulses and with a pulse width reference variable (34), wherein a reflection is detected as caused by the environmental fault false target when the pulse width of the reflex pulses at first pulse detection is smaller than the pulse width reference variable (34).

Description

The invention relates to a method for discriminating an environmental disturbance such as camouflage mist, smoke or the like according to the preamble of claim 1 and a device for carrying out this method according to the preamble of claim 4.

Optronic detonators, which are to recognize unfavorable tactical targets such as matte black camouflage finishes, require a high sensitivity. However, such a high sensitivity leads to environmental disturbances with a high particle density, such as a dense smoke or a camouflage fog, along the trajectory of the missile having such an optronic detonator to measurable reflex signals. This is particularly problematic if the particle density of the environmental disturbance is so great that there are back reflections of the particle field around the specified intentional firing distance of the optronic detonator.

Conventional optronic detonators are unable to perform appropriate discrimination against environmental disturbance such as camouflage fog, smoke or the like. The result of this is that in conventional optronic detonators false triggering occurs too far away from a target to be counteracted.

The DE 100 26 534 A1 discloses a laser range finder for a detonator wherein good range resolution is achieved by providing a trigger not only for triggering the rising edge of the laser pulse but also for triggering the falling edge of the laser pulse. The trigger is preferably a Constant Fraction Trigger (CFT). The CFT preferably has a delay element and two comparators whose outputs are connected together with an AND gate.

A method for detecting and discriminating mask, half-mask and oblique targets using optronic ignition sensors with dual-gate Pulslaufzeitmeßverfahren is known from DE 42 24 292 C1 known. In this known method, it is proposed that the individual transmitters emit different pulse sequences and each receiver is supplied with the pulses of each transmitter remitted by the target, the mean value and / or the difference integral and / or the correlation integral being formed from the output signals.

The DE 196 07 345 A1 describes a laser distance detection device with a pulse laser, a light deflector, a photoelectric receiver having a photoreceptor arrangement, and a control and evaluation, in the after the impulse transit time from the time between the transmission and receiving a light pulse, taking into account the speed of light for the distance of an object representative sampling signal is detected. The control and evaluation of this known laser distance detection device comprises means for measuring the total of the photoreceiver flowed during the reception of a light pulse electric charge and / or for measuring the pulse width of the received light pulse. Compensation of the propagation time errors occurring due to the signal dynamics occurs as a function of the measured electrical charge or pulse width on the basis of respective correction values, which are determined by the control and evaluation electronics on the basis of charges or pulse widths and pulse transit times, with respect to at least one defined Distance from the light deflector arranged, different reflectivities having reference object were measured.

An optical radar, in particular laser radar for taking distance images or reflection images with a light source, a light receiver and a processing device is known from DE 39 15 627 A1 known. In this optical radar, the light source and the receiver are formed as a diode array, which cooperate with at least one imaging optics that a light pulse from a particular transmitter diode is reflected by reflection in a particular grid of the object to a specific receiver diode.

From the DE 40 11 391 C1 a device is known for a distance fuse with transit time measurement by means of a transmitter for generating sampling pulses and a receiving circuit coupled to the transmitter. In the receiving circuit, the energy contents of the reflected sampling pulses are filtered by means of range gates. In this case, at least one removal gate is arranged ahead of time and at least one removal gate after the target triggering distance. The pulse components filtered out in this way are respectively fed to integrators whose integrator voltage is evaluated for the purpose of generating a triggering signal. Signal processing circuits are provided which check the integrator output signal of a distance gate arranged after the desired triggering time to determine whether a predetermined minimum amplitude has been reached and / or an adjustable minimum time has been exceeded.

The invention has for its object to provide a method and a device of the aforementioned type to realize a fail-safe optronic distance sensor.

This object is achieved according to the method by the features of claim 1. Preferred developments of the method according to the invention are characterized in claims 2 and 3.

The problem underlying the invention is achieved according to the device by the features of claim 4. A preferred embodiment of the device according to the invention is characterized in claim 5.

Measurements of an environmental disturbance, such as a camouflage fog, show that reflex amplitudes occur which are smaller than, for example, the reflection amplitudes of a matt black finish. This leads to the fact that in the case of a continuous approach of the missile having an optronic detonator to an environmental disturbance, such as a camouflage fog, this can only be recognized at a smaller distance than, for example, tar black.

If, for example, the missile having an optronic detonator enters a camouflage fog, a very high diffuse backscatter occurs in the near range, which usually fades the optronic detonator. Only when leaving the Tarn Nebula the glare drops and the optronic detonator can recognize targets again. Due to the inhomogeneous attenuation of the camouflage nebula, several target reflexes can occur in it. Typically, in a designed with matte black reflectors system with pulse transit time measurement has the further effect that even worse reflectors such as camouflage have a lower reflective pulse width than the associated transmission pulse width. This is due to the proximity to the trigger limit of the mentioned system designed for matte black reflectors. This effect is typical for multiple reflexes in a cloak-fog.

A system that should therefore discriminate, for example, camouflage fog, must be able to recognize these combinatorial combinatorial and link. The sensor basis for this must determine the distance of the reflex pulse and compare this distance with an empirically determined logical distance threshold (CFAR distance), below which all reflections or targets occurring in the target approximation are classified as false targets. This applies not only to camouflage fog and smoke, but in the same way, for example, for snowfall, hail, rain or the like.

If multiple echoes occur during flight through the cloak nebula or the like, the reflex pulse size must be equal to or wider than the transmit pulse width and the first detect distance greater than the CFAR distance for valid target discrimination - dull black targets can not be detected. In this way, a misfire mist is avoided. If the missile having an optronic detonator exits the fog field, it can be triggered to a new target if it is detected for the first time at a distance that is greater than the above-mentioned CFAR distance, or if also the reflex pulse size at least equal is greater or greater than the transmission pulse width.

An embodiment of the device according to the invention for carrying out the method according to the invention for the discrimination of an environmental disturbance is illustrated in the drawing and will be described below. The figure shows a block diagram of a device 10 for discriminating an environmental disturbance, such as camouflage fog, smoke or the like, along the trajectory of an optronic detonator and a sensor base 12 with a measuring unit 14 having (not shown) missile. At the measuring unit 14 it is a trigger with runtime measurement. The measuring unit 14 serves to determine the removal of reflex pulses. This is through the angled arrow line 16 indicated between the measuring unit 14 and a first entrance 18 a first comparator 20 represents an active compound. The first comparator 20 has a second entrance 22 through, into the first comparator 20 a signal corresponding to a logical distance threshold (CFAR distance) is input. This logical distance threshold (CFAR distance) is through the block 24 clarified.

The measuring unit 14 is also provided to determine the pulse width of reflex pulses. This is through the angled arrow line 26 indicated that an operative connection between the measuring unit 14 and a first entrance 28 a second comparator 30 clarified. The second comparator 30 has a second entrance 32 through, into the second comparator 30 a pulse width reference is entered. The pulse width reference size is through the block 34 indicated.

The first comparator 20 has an exit 36 and the second comparator 30 has an exit 38 on, with entrances 40 and 42 an AND gate 44 are interconnected. In a simpler embodiment, the AND gate 44 be replaced by an OR gate.

The device 10 takes advantage of the lower remission of, for example, a cloaking fog compared to valid targets. That's why the sensor base can 12 , which seeks targets on the approach and which operates with high sensitivity, first detect a camouflage fog or smoke field at a certain distance, which is slightly smaller than the detection distance of normal tactical targets. At the same time there is the effect that the measuring unit 14 , ie the trigger, forms narrower pulses from the smaller signals. The device according to the invention therefore checks whether a minimum distance, ie CFAR distance, and a minimum pulse width, ie CFAR pulse width, is present in order to classify a measured value as valid and to activate the igniter of the missile.

LIST OF REFERENCE NUMBERS

10

Facility

12

Sensor base (from 10 )

14

Measuring device (from 10 )

16

angled arrow line (between 14 and 20 )

18

first entrance (from 20 )

20

first comparator (from 10 )

22

second input (from 20 )

24

logical distance threshold (CFAR removal)

26

Arrow line (between 14 and 30 )

28

first entrance (from 30 )

30

second comparator (from 10 )

32

second input (from 30 )

34

Pulse Width Reference Size (CFAR Pulse Width)

36

Output (from 20 )

38

Output (from 30 )

40

Entrance (from 44 )

42

Entrance (from 44 )

44

AND gate

Claims (5)

Method for discriminating an environmental disturbance, such as camouflage fog, smoke or the like, along the trajectory of an optronic detonator and a sensor base ( 12 ) with a measuring unit ( 14 ), characterized in that the measuring unit ( 14 ) determines the pulse width of reflex pulses and with a pulse width reference variable ( 34 ), whereby a reflection is recognized as a false target caused by the environmental disturbance, if the pulse width of the reflex pulses at first-time pulse detection is smaller than the pulse width reference variable ( 34 ). Method according to claim 1, characterized in that the measuring unit ( 14 ) determines the removal of reflex pulses and the distance of the reflex pulses is compared with a logical distance threshold, wherein a reflection is detected as due to the environmental disturbance false target, when the reflection pulse distance at first pulse detection is less than the logical distance threshold. Method according to one of claims 1 to 2, characterized in that the sensor base ( 12 ) temporarily ignited for the first time pulse detection, if a false target has been detected. Device for discriminating an environmental disturbance, such as camouflage fog, smoke or the like, along the trajectory of an optronic detonator and a sensor base ( 12 ) with a measuring unit ( 14 ), characterized in that the measuring unit ( 14 ) is provided for determining the pulse width of reflex pulses and a comparator ( 30 ) for comparing the pulse width of the reflex pulses with a pulse width reference variable ( 34 ), wherein a reflection is detected as caused by the environmental fault false target when the pulse width of the reflex pulses at first pulse detection is smaller than the pulse width reference variable ( 34 ). Device according to claim 4, characterized in that the measuring unit ( 14 ) is provided for determining the removal of reflex pulses, wherein the distance of the reflected pulses is compared with a logical distance threshold, wherein a reflection is detected as caused by the environmental fault false target when the reflected pulse distance at the first pulse detection is less than the logical distance threshold.

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