SYSTEM FOR DETERMINING STATE OF ALARM FOR LIMITED SPACE (VERSIONS) Russian patent published in 2016 - IPC G08B29/00 G08B13/04 G01S13/04 

FIELD: safety.

SUBSTANCE: invention relates to systems of intrusion detection in closed space. System for determining the state of alarm for a limited space is characterized by that it contains a processing unit designed to receive from the ultrasonic receiver intended for reception and detection of an ultrasonic acoustic signal having a Doppler frequency change and for generation of an electric signal acknowledging the above mentioned Doppler frequency change, as well as from the low-frequency receiver for receiving and detecting an audio acoustic low-frequency signal and for generation of an electric signal acknowledging the said low-frequency signal, the said electrical signals supporting the presence of an ultrasonic acoustic signal with a Doppler shift and an acoustic low-frequency signal; the said processing unit is programmed to generate an alarm signal if the above said signals are received within a certain time interval.

EFFECT: technical result is reduction of the probability of false triggering at the system operation in compliance with its purpose.

12 cl, 3 dwg