Abstract
Since Global Navigation Satellite Systems (GNSS) show degraded performance in dense urban and indoor areas, a positioning sensor based on Digital Video Broadcast-Terrestrial (DVB-T) systems is presented in this paper. DVB-T signals can be considered as signals-of-opportunity for positioning, due to their good properties. 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. Starting from there, DVB-T signals can be used for aiding 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 Hata model for the emitter attenuations and the Rayleigh model for multipath. The obtained results show good performance if the receiver correctly associates the signal to the user's motion.
Highlights
Global Navigation Satellite Systems (GNSSs) have been widely used in many applications for positioning, navigation and timing
If the position device (PD) is able to receive the closest signal, the signals broadcast by emitters with ∆i < ∆pmax can be detected, and the relative delays of these emitters can be estimated by using the same techniques used for the reception of the useful signal
This method uses the scattered pilot subcarriers of Orthogonal Frequency Division Multiplexing (OFDM) symbols to measure the Time of Arrival (ToA) of the signals transmitted by the Digital Video Broadcast-Terrestrial (DVB-T) emitters
Summary
Global Navigation Satellite Systems (GNSSs) have been widely used in many applications for positioning, navigation and timing. Sensors 2013, 13 and availability, because of the signal loss or attenuation and multipaths due to obstacles In these areas, many local networks are deployed, such as 2G, 3G, WiFi, LTE (Long Term Evolution) and DVB-T (Digital Video Broadcast-Terrestrial). They were originally designed for other purposes, but they can be used for positioning, thanks to their properties, such as a high signal-to-noise ratio (SNR). The whole bandwidth is divided into many subcarriers, in which the pilot subcarriers are included We used these pilot subcarriers to estimate the ranges between the receiver and different emitters with a mechanism similar to the one used by GNSS receivers. If three or more signals are successfully processed, the receiver can provide a DVB-T only the positioning; otherwise, it can be used to assist GNSS
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