Procedure and device for monitoring a risk zone, especially a bathing area

摘要

Procedure for the surveillance of an outdoor space, called a guarded space, by a system that includes: a. a surveillance computer network comprising transmission-reception means (110) in a frequency band between 135 MHz and 175 MHz (135,106 to 175,106 hertz) according to a non-simultaneous bidirectional mode and whose geographical coverage is equal to or greater than that of the guarded space; b. a portable device (351, 352, 450) comprising a satellite positioning chip and means for transmitting and receiving information on the surveillance computer network; c. computer means (140) connected to the surveillance computer network and comprising in memory means a geo-referenced mapping of the monitored space and a virtual geo-fence of a surveillance area (515), the geographic area of which falls within the geographic scope (510) of the means of emission-reception of the computerized surveillance network, and of the display means (181) that allow viewing of the monitored space; Said procedure includes the stages consisting of: i. delimit by virtual geo-fencing a surveillance area (515) on georeferenced cartography; ii. emitting by the portable device in the surveillance network, at regular intervals, an information frame comprising, an individual identifier of said portable device, the geolocated position of this portable device and the state of difficulty of said portable device; iii. record in the memory means of the computer system the geolocated position of said device and the time stamp of said position; iv. showing in the display means of the computer means the position of the portable device in the cartography when the state of difficulty transmitted by the portable device corresponds to a dangerous situation; characterized in that it comprises the stages consisting of: vi. record in a historical file the geolocation of the difficult situations detected; vii. delimit by virtual geo-fencing, in the surveillance area, an area (514), called a risk zone, based on the records contained in the historical file.