Warning method, system and device based on transmission of acoustic signals

Box (9) intended to help prevent drowning accidents:

• said box (9) comprising at least one transmitting antenna (2) and one receiving antenna (3) of a sonar (1);
• said transmitting (2) and receiving (3) antennae having a transmission axis (4) and a reception axis (5) and possibly being in the form of a single antenna;
• said sonar (1) being of parametric sonar (1) type having high spatial directive gain along said transmission axis (4) and/or reception axis (5);
• the angular aperture of the transmission lobes (17) and/or reception lobes (18) of said transmitting (2) and/or receiving (3) antennae being in the order of one degree or less;
• said transmitting (2) and receiving (3) antennae being intended to deliver acoustic signals and to receive electric signals or conversely;
• said electric signals being intended to be transmitted to a processing calculator (6) via amplification means (7) and transmission means (8);
• said boxes being intended to be fixed to the wall (10) or bottom (11) of the swimming pool (12);
• said box (9) optionally comprising:
• swivel supports (13) on which said transmitting and receiving antennae are mounted, and/or being in the form of a hollow ball joint (20) inside which said transmitting (2) and receiving (30) antennae are mounted, and/or
• orientation means (14) to activate said swivel supports (13) or said hollow ball joint (20) and to direct said transmission axis (4) or reception axis (5) of said transmitting (2) and receiving (3) antennae in a particular direction in space, and/or
• modulation means (15) to modulate the acoustic energy transmitted by said sonar (1);
• said modulation means (15) being used, by an audible low frequency signal, to modulate the acoustic energy transmitted by said sonar (1);
• said low frequency signal particularly carrying a vocal message to a swimmer (16), and/or
• transmitting (2) and receiving (3) antennae such that said transmission lobes (17) and/or reception lobes (18) are coaxial and directed along the transmission axis (4) and reception axis (5) of said transmitting (2) and receiving (3) antennae, and/or
• amplification means (7) and/or transmission means (8) for said electric signals towards said processing calculator (6).

Method to help prevent drowning accidents, said method comprising the step for detecting a swimmer (16) and his/her position by using a parametric sonar (1) having high spatial directive gain, whose transmission lobes (17) and/or reception lobes (18) have an angular aperture in the order of one degree or less;

• said method optionally comprising:
• the step of estimating the extent of mobility of the swimmer (16), and/or
• the step of estimating the quantity of air remaining in the lungs of said swimmer (16), and/or
• the step of transmitting audible signals to said swimmer (16) by means of said parametric sonar (1).