Method and a system for the localisation of a communication device

A method for localising a communication device (1), wherein an assignment is made of field strengths measured on the communication device (1) to a location by measuring field strengths of at least one radio network (2) at known locations, characterised in that the method comprises the following steps:

• a) a calibration phase, in which for at least one radio network (2) for at least one communication device (1) and using a reference receiver (3), an assignment made of the reference field strength (4) received by the reference receiver (3) to the terminal field strength (5) received by the respective communication device (1) and possibly of other data, is recorded and stored;
• b) a measuring phase in which for at least one radio network (2) a field strength is recorded at known locations within the reception area, and processed and stored as a fingerprint (6) preferably together with further data;
• c) a post-processing phase, in which the data recorded in the calibration phase and the measuring phase are made available at least partially to the communication device preferably together with a map (7) and further meta data;
• d) a localisation phase, in which the field strength of at least one radio network (2) is received at the communication device (1) and in which the location of the communication device (1) is at least approximately determined from the received terminal field strength (5) and/or the data recorded during the calibration phase and the measuring phase.