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

摘要

The invention concerns a warning system to help preventing drowning accidents. The system comprises at least a sonar (1). Each sonar (1) comprises at least a transmission antenna and a reception antenna having transmission (4) and reception (5) apertures. The sonar (1) is a parametric sonar with high spatial directive gain along said transmission (4) and/or reception (5) apertures. The angular opening of the transmission (17) and/or reception (18) lobes of said transmission and/or reception antennae is of the order of one degree or less than one degree. The system comprises a processing calculator. The sonar (1) comprises amplifier means and transmission means for amplifying and transmitting the electric signals coming from said reception antenna.