As an alternative or add-on to satellite-based positioning systems, positioning systems in which a present position of a terminal is estimated based on an identification of coverage areas that can currently be detected by the terminal have gained recent interest. For instance, a terminal may identify and receive a signal characteristic representative of all currently detectable coverage areas, which are provided by wireless Coverage-Providing Entities (CPEs) (such as for instance base stations of a cellular Communication System (CS), or Wireless Local Area Network (WLAN) Access Points (APs)), and consult a local or remote database that provides positioning reference data in order to compare the signal characteristic representative of all currently detectable CPEs with the positioning reference date for obtaining or estimating the local position.
For instance, the CPEs may represent WLAN APs and the positioning reference data may be used for indoor positioning. The WLAN infrastructure is widely deployed—practically everywhere in the developed world public buildings, office spaces etc. are equipped with a WLAN connectivity. Moreover, typically there is a lot of diversity in the WLAN signal space because of the high number of access points deployed in these buildings. But any other suited CPEs may be used for positioning, e.g. base stations of cellular Communications Systems or other wireless transmitting stations.
Positioning based on CPEs typically has two phases. In the first phase the signals of the CPEs are received and fingerprints of the signal characteristic of the received signals of the CPEs are taken at different positions in order to generate or obtain a database. This database may be used in as second phase for estimating the position of a terminal when the received signal characteristics of the received signals of the CPEs are compared with the fingerprints in the database.