Digital television (DTV) signal is a promising signal of opportunity (SoO) for wireless positioning. This paper studies the time of arrival (TOA) estimation on the European standard DVB-T signals in the context of positioning. Theoretical analysis on the autocorrelation of the pilot signal and multipath error envelop (MEE) suggests that DVB-T has the appropriate characteristics for positioning. A software defined radio (SDR) based DVB-T receiver is developed for field testing, in which the radio frequency (RF) DVB-T signals are first sampled by USRP (Universal Software Radio Peripheral), and then algorithms of the coarse symbol synchronization, the pilot detection, the first path acquisition and the delay tracking are sequentially performed to obtain the TOA estimation. To quantify the TOA tracking results on real DVB-T signals, field testing campaigns are carried out in five cities in Southern France. Test results showed that, in the high signal-noise ratio (SNR) condition, the 2-σ error interval is within 1 meter. By taking into account all the field tests, the interval of 95 % accuracy is within 4 m and the corresponding C/N 0 varies from 48 to 62 dB-Hz. In addition, with the developed TOA estimation method, the synchronization of the emitters with GPS (Global Positioning System) time is evaluated and the distance difference of the multiple emitters within single frequency networks (SFNs) are also measured during the tests.

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One of limitations of the current GNSS signals is their low data information rate. This low data information rate does not allow, for example, the transmission of additional commercial services or the transmission of redundant ephemeris data. The Code Shift Keying (CSK) is a signaling technique specifically designed to increase the transmission bit rate of a spreading spectrum signal. Therefore, one solution to increase the data information rate of the GNSS signals is to introduce the CSK technique in them. In this paper, the implementation of the CSK technique into GNSS signals is inspected through the development and analysis of the likelihood ratio expression of the bits transmitted inside a CSK symbol, and through the identification of the best mapping between bits belonging to a word and bits transmitted inside a CSK symbol.Finally, the impact of the CSK technique on the GALILEO E1 signal is analyzed by calculating the CSK demodulation performance for a given scenario and the drawbacks of the technique on the signal acquisition and tracking processes.

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