Patent ID: 7430547

Claim:
A method of tracing a path to be taken by a mobile terminal capable of receiving electromagnetic waves transmitted by one or more transmitter stations, said path being traced by an operating platform, which method comprises: a learning phase comprising: an initial reconnaissance of the path during which, exclusively on said path, a periodic routine learning recording of successive groups of samples is made in a route memory accessible by said operating platform, a sample comprising at least one value of each of the frequencies received by said mobile terminal at each geographical position occupied by said mobile terminal at the time of said periodic recording and a receive level associated with said frequency, a periodic recording of rank k comprising a group k of p k samples, p k being an integer equal to the number of different frequencies received at the time of said recording, and a comparison of the received levels for a group of P n samples recorded during a current sampling of rank n and for at least one recorded preceding group of samples of rank lower than n, a comparison criterion discriminating between remarkable groups of samples and ordinary groups of samples, and an operating phase during which said mobile terminal takes said predefined path, said operating phase comprising: periodic routine operating recording of groups of p j operating samples, an operating sample comprising at least one value of each of the frequencies received by said mobile terminal at each geographical position it occupies at the time of said periodic operating recording and a receive level associated with said frequency, the number p j of samples being equal to the number of frequencies received during said operating recording of rank j, comparing each group of operating samples with at least one of said remarkable groups of samples, said comparison producing a positive comparison result if, according to the comparison criterion adopted for said learning phase, said comparison result indicates that said current group would have been classified as ordinary, recording a presence indication relating to whether said mobile terminal is on said path to be taken or not in the event of a positive comparison result and otherwise recording an absence indication, and processing one or more of the recorded presence or absence indications to decide if said mobile terminal is on said path to be taken or not.