The use of RSSI, (Received Signal Strength Indication) for problems of heritage location, which is the best technique, to create a map of patterns or triangulation.
A well-trained offline radio map provides accurate fingerprinting performance (meter level ) than multi-lateration techniques since the later are prone to multi-path and NLOS effect.
Ahmed Mansour Good to know, I am creating a map to be used in times of low flow of people, at dawn, to avoid interference and the time of the search will also be only in this period.