Study of positioning methods in DVB-T single frequency networks

In this paper, we study a positioning method working in DVB-T single frequency networks (SFNs). These networks have several properties useful for positioning (synchronized emitters at fixed and known location, high SNR, OFDM signals containing pilot subcarriers). Thus, their signals may be used as signals-of-opportunity when the user enters a GNSS hostile environment (e.g. dense urban or indoor areas). One of the challenges to overcome is to distinguish the signals from different emitters. Here we suppose that the user can first compute his position by GNSS during an initialization phase, which is used for solving all the ambiguities concerning DVB-T emitters. After that, DVB-T signals can be used to aid positioning when the user enters a GNSS-blocked area, up to a limit case where all the GNSS satellites are not in view and only DVB-T signals are used for positioning. We tested this method by simulation, by adopting the free space loss model for the emitter attenuations and a two ray model for multipath. The obtained results show good performance if the receiver correctly associates the signal during the user´s motion.