RU2352959C1 - Device for definition of angle coordinates of pulsed laser radiation source - Google Patents

Abstract

FIELD: physics, optics.

SUBSTANCE: invention is related to instruments for determination of angle coordinates of pulsed laser radiation sources and may be used in protection of different objects against directed aiming. Device comprises control unit, photodetector on the basis of photodiode, two superwide-angle lenses, in focal plane of which two light-sensitive matrices are installed accordingly; time for accumulation of signal of every light-sensitive matrices, on the one hand, is so insignificant, that it provides for absence of day background, and on the other hand, it exceeds time for reset of accumulated signal by second matrix, which provides for continuity of space viewing; control unit connected to the first and second light-sensitive matrices and with photodetector device, provides for alternate accumulation of signal by light-sensitive matrices and determines angle coordinates of pulsed laser radiation source and time of signals appearance at the outlet of photodetector; light-sensitive matrix in mode of signal accumulation at the moment of signal appearance at photodiode outlet, on completion of accumulation mode transferring into mode of signal reading by control unit; at that analysis of time-pulse modulation of signal at the outlet of photodetector may be used for recognition of friend or foe.

EFFECT: increased distance of laser radiation source and space viewing angle detection, increased accuracy of laser radiation source angular position measurement, and possibility to control surrounding space in continuous mode, which increases possibility of aiming device detection and destruction of enemy adjusting their sights.

5 cl, 2 dwg

Description

The invention relates to devices for determining the angular coordinates of pulsed laser radiation sources and can be used to protect various objects from directional aiming.

Various types of modern systems are known that make it possible at any time of the year or day to detect attack means at long ranges and in a wide range of heights, determine their exact coordinates and nationality, and a whole arsenal of sights and night-vision devices used to detect enemy combat units and guidance is known for the purpose in which pulsed laser radiation sources are used, therefore, there is a need to develop means of counteracting detection and aiming.

Known small-sized laser ranging equipment for remote reconnaissance of optical and optoelectronic means "Antisniper-M" http://www.ess.ru/publications/2_2004/volkov/volkov.htm. The Antisniper-M device uses a laser illuminator; a CCD matrix with a digital image processing unit is used to increase the sensitivity of the receiving channel. In this case, an increase in sensitivity is achieved due to the spatial and temporal integration of the signals of the storage elements of the matrix. A disadvantage of the known laser location equipment is the short detection range due to the active principle of construction, and the inability to control the surrounding space in a continuous mode.

A device for detecting laser radiation sources, selected as a prototype (RU 2248587C2, 03.20.2005) is known. The known device includes, including a detection unit, consisting of two sensors, and a control unit that allows you to determine the angular coordinates of the sources of laser radiation. However, in the known device as the detection sensors, it is proposed to use elements of a passive location, such as multi-element IR sensors or infrared homing heads. Such sensors, for reasons of background selection, fundamentally have a small angular field, and also using a known device it is impossible to control the surrounding space in a continuous mode.

The technical result of the invention is to increase the detection range of the laser source and the viewing angle of the space to a value of at least a hemisphere, the ability to control the surrounding space in a continuous mode and increase the accuracy of determining the angular coordinates of the laser source.

The proposed device for determining the angular coordinates of a pulsed laser radiation source includes a control unit, a photodetector based on a photodiode, two ultra-wide-angle lenses, in the focal plane of which are respectively two photosensitive arrays, the control unit being connected to both photosensitive arrays and a photodetector. The signal accumulation time of each of the photosensitive matrices, on the one hand, is so short that it ensures the absence of a daylight background, and, on the other hand, exceeds the time of accumulation of the accumulated signal by the second matrix, which ensures continuous viewing of the space. The control unit provides sequential accumulation of the signal by the photosensitive arrays and switches at the time of the appearance of the signal at the output of the photodetector of the photosensitive matrix, which is in the accumulation mode, after its completion, into the mode of reading the signal by the control unit. The latter has the ability to determine the angular coordinates of a pulsed laser radiation source and the time of appearance of pulses at the output of the photodetector.

In addition, the photodetector may further comprise an input optical element mounted in front of the photodiode and made in the form of a hemispherical lens made of scattering material, such as milk glass.

In addition, a serial interface for exchanging information with external devices connected to the signal processing unit can be additionally introduced into the device.

Figure 1 shows the functional diagram and composition of the proposed device for determining the angular coordinates of the source of pulsed laser radiation.

1 - an ultra-wide-angle fisheye lens (190 °);

2 - photosensitive matrix (CMOS 640 × 480);

3 - photodetector based on a PIN photodiode;

4 - hemispherical lens made of milk glass (MC20);

5 - electronic control unit;

6 - serial interface for exchanging information with external devices;

7 - external power to the device;

Figure 2 shows the timing diagrams of the device for determining the angular coordinates of the source of pulsed laser radiation.

8 - signal accumulation on the first matrix;

9 - reset information on the first matrix;

10 - signal accumulation on the second matrix;

11 - reset information on the second matrix;

12 - pulses of the photodetector;

13 - reading the signal from the second matrix, since the first of the pulses of the photodetector on the time diagram came during the accumulation of the signal on the second matrix;

14 - processing of the read information (signal) in the electronic control unit.

The device used ultra-wide-angle lenses 1 of the type “fisheye” and a photodetector 3 based on a photodiode with an additional scattering element, which increases the spatial viewing angle of the device to a hemisphere. A device for detecting pulsed laser radiation and determining its coordinates can be used, for example, in systems for detecting an aircraft, combat vehicle, etc., equipped with a laser rangefinder or illuminator.

The proposed device operates as follows.

The initial state in which the device is located most of the time is “waiting” for the arrival of the laser pulse. In this state, the control unit 5 provides the alternate accumulation of the signal 8, 10 (FIG. 2) by the photosensitive matrices 2, which makes it possible to monitor the surrounding space in a continuous mode and, in the absence of a pulse from the photodiode receiver 3, alternately reset the accumulated signal 9, 11 (FIG. 2). The minimum exposure time of the photosensitive matrix is determined by the fact that during this time it is necessary to have time to dump the accumulated signal from another matrix. The reset time of the accumulated signal does not exceed 10 μs, while for reading the signal it takes about 10 ³ times longer, that is, about 10 ms.

Upon receipt of a pulse 12 (Fig. 2) from a photodetector 3, indicating the fact that the device was irradiated with a laser pulse, the control unit 5 switches the matrix that is currently accumulating the signal, after the end of the accumulation mode (end of exposure time), into the state of reading the signal (information) the control unit 5, and not in the reset state, as before.

With the beginning of reading 13 (Fig. 2) by the image control unit 5 with one of the matrices, the control unit 5 starts a cycle of determining the angular coordinates of the source of the registered (arrived) laser radiation pulse 14 (Fig. 2). The procedure for measuring angular coordinates takes an additional no more than 6 ms.

And at the same time, the control unit 5 terminates the accumulation mode of the signal by both matrices until the signal is processed and the angular coordinates are determined.

After the procedure for measuring the angular coordinates is completed, the device provides the angular coordinates and time of arrival of the pulse registered by the photodetector via the serial interface for exchanging external devices 6, after which it again returns to its original state, “waiting” for the arrival of the next pulse. In this case, the control unit 5 again provides a mode of alternating signal accumulation by the photosensitive matrices 2.

In addition, simultaneously with each incoming pulse from the photodetector 3, even during the procedure of measuring the angular coordinates of the previously received pulse, the control unit 5 fixes the arrival time of the next laser pulse 12 (Fig.2) and sends information to the external device about the time of arrival of the pulse and time interval from the moment of registration of the previous impulse. An analysis of the time-pulse modulation of the radiation of a laser source can be used for the purpose of recognizing friend or foe.

Thus, the device can measure the angular coordinates of incoming pulses of laser radiation with a frequency of up to 60 Hz and record the time of arrival of laser pulses with a frequency of up to several MHz. In addition, the safety of the crew of an airplane or combat vehicle that uses the proposed device is increased, since the proposed device operates in a passive mode and, therefore, does not detect itself and at the same time continuously monitors the surrounding area to detect laser guidance systems for an airplane or combat vehicle, having this device.

Claims (5)

1. A device for determining the angular coordinates of a pulsed laser radiation source, comprising a control unit, characterized in that it contains a photodetector based on a photodiode and two ultra-wide-angle lenses, in the focal plane of which are respectively two photosensitive arrays, while the control unit is connected to the first and the second photosensitive arrays and with a photodetector, provides alternate signal accumulation by photosensitive arrays and determination of angular coordinates Inat of a pulsed laser radiation source and the time of appearance of the signals at the output of the photodetector, moreover, the analysis of time-pulse modulation of the signal at the output of the photodetector is used to recognize friend or foe targets. 2. The device according to claim 1, characterized in that the accumulation time of the signal of each of the photosensitive matrices, on the one hand, is so short as to ensure the absence of a daylight background, and on the other hand, exceeds the reset time of the accumulated signal by the second matrix, which ensures continuous viewing space. 3. The device according to claim 1, characterized in that the photosensitive matrix, which is in the mode of accumulation of the signal at the time of the appearance of the signal at the output of the photodiode, after the completion of the accumulation mode switches to the mode of reading the signal by the control unit. 4. The device according to claim 1, characterized in that the photodetector further comprises an input optical element mounted in front of the photodiode and made in the form of a hemispherical lens made of scattering material, such as milk glass. 5. The device according to claim 1, characterized in that the serial interface for exchanging information with external devices connected to the control unit is additionally introduced.

Images