Method and system for searching for a beacon using a detection device

A method for searching for a beacon, the search method being executed by a detection device comprising a geolocation terminal capable of determining current geolocation coordinates of the detection device and a radio receiver capable of detecting a radio signal emitted by the beacon, the search method comprising the following steps:

• receiving the radio signal emitted by the beacon;
• determining a separation distance between the detection device and the beacon on the basis of a measurement of a time of propagation of the radio signal between the beacon and the detection device, or a measurement of a quantity representative of the power of the radio signal emitted by the beacon and received by the detection device like an RSSI, or a combination of the measurement of the time of propagation of the radio signal and the quantity representative of the power of the radio signal, the said step of determining the separation distance between the detection device and the beacon is periodically done so as to have a new estimate of the separation distance at each period when the detection device moves;
• determining at least one localization position of the beacon based on the current geolocation coordinates of the detection device and the determined separation distance;
• the determination of at least one localization position of the beacon comprising the steps of:
• determining a search space of the beacon;
• dividing the search space into a grid comprising a plurality of sub-areas;
• assigning relative coordinates to each sub-area, these relative coordinates being fixed for each sub-area and calculated with respect to reference coordinates of a center of the grid,
• calculating a current probability indicator for each sub-area, for each estimate of the separation distance between the detection device and the beacon, the current probability indicator being representative of the probability that the beacon is within the sub-area,
• the current probability indicator being calculated according to previous probability indicators and the determined separation distance between the beacon and the detection device and according to the current geolocation coordinates of the detection device,
• selecting the sub-areas for which the probability indicator has the highest values, as representative of a most probable location of the beacon.