METHOD FOR DETECTION OF INTRUSION INTO MONITORED SPACE WITH GUARDED OBJECT AND DEVICE WHICH IMPLEMENTS SAID METHOD Russian patent published in 1998 - IPC

FIELD: equipment for generation of alarm signals in guarding optoelectronic systems. SUBSTANCE: method involves sending preliminary modulation of part of laser single-mode coherent light beam by one of its characteristics (amplitude, frequency or phase) and directing it to guarded object, splitting beam residual and coherent reception of optical mix of residual with signal which is reflected from guarded object, detecting electric signals for one of which frequency is equal to difference of frequency of reflected and split beam and frequency of another one is equal to modulation frequency. Amplitudes of detected electric signals are used as monitored parameters by which intrusion is judged. Corresponding device has laser, which is optically connected to optoelectronic unit, which has light-splitting plate, spherical mirror and transmitting telescope, which is optically connected to guarded object. EFFECT: increased reliability of detection. 2 cl, 1 dwg