Assessment of Galileo E6B Data Demodulation Performance at High Latitudes: A Norwegian Vessel Case Study  
[PERSON]  
1 Joint Research Centre, European Commission, I-21027 Ispra, VA, Italy; [EMAIL_ADDRESS] (D.B. ); [EMAIL_ADDRESS] (C.G.) [PERSON]  
2 Norwegian Mapping Authority, N-3507 Henefoss, Norway; [EMAIL_ADDRESS] (M.T.B. ); [PERSON]SS] (M.D. ); [EMAIL_ADDRESS] (G.G.) [PERSON]  
1 Joint Research Centre, European Commission, I-21027 Ispra, VA, Italy; [EMAIL_ADDRESS] (D.B. ); [EMAIL_ADDRESS] (C.G.) [PERSON]  
2 Norwegian Mapping Authority, N-3507 Henefoss, Norway; [EMAIL_ADDRESS] (M.T.B. ); [PERSON]SS] (M.D. ); [EMAIL_ADDRESS] (G.G.) [PERSON]  
2 Norwegian Mapping Authority, N-3507 Henefoss, Norway; [EMAIL_ADDRESS] (M.T.B. ); [EMAIL_ADDRESS] (M.D. ); [EMAIL_ADDRESS] (M.T.B. ); [EMAIL_ADDRESS] (G.G.) [PERSON]  
2 Norwegian Mapping Authority, N-3507 Henefoss, Norway; [EMAIL_ADDRESS] (M.T.B. ); [EMAIL_ADDRESS] (M.D. ); [EMAIL_ADDRESS] (M.T.B. ); [EMAIL_ADDRESS] (M.T.B.) [PERSON]  
3 Norwegian Space Agency, 0277 Oslo, Norway; christian.rost@space  
A receiver will be able to recover the original message by collecting any subset of unique \(K\) encoded pages; this property is ensured by the Reed-Solomon encoding scheme [4; 5], which has been designed to minimize the Time-to-Retrieve Data (TTRD), i.e., the time needed by a receiver to recover the HAS message [3]. The performance in terms of TTRD was analyzed in [7; 8] considering highway and suburban environments. From those analyses, it emerged that the final receiver performance depends on the reception environment and on the ability of the receiver to correctly decode the E6B navigation message. The analyses showed that the HAS dissemination scheme is effective in coping with channel erasures and that the HAS message can be recovered with a high probability within 30 s. The analyses were, however, limited to two scenarios (highway and suburban environment) and data were collected at mid-latitudes. Finally, less than eight hours of data were considered for the analyses. Additional field tests on the Galileo HAS were performed, and considered open-sky, urban and suburban scenarios. Moreover, in this case, which is described in [9], only mid-latitude conditions and relatively short datasets were considered. The goal of this study was to extend previous analyses by assessing the demodulation performance of the Galileo E6B signal. The focus of this work is on high-latitude conditions where satellite visibility may be partially reduced [10]. A professional Septentrio PolaRx5S was installed on a Hurtigruten vessel operating in the Norwegian Sea and reaching latitudes exceeding 71 degrees North. At these latitudes, the Position Dilution Of Precision (PDOP) can be reduced, as discussed in [10; 11]. Moreover, adverse ionospheric conditions [12; 13; 14] can further degrade receiver performance, reducing demodulation capabilities. Challenges of GNSS-based navigation at high latitude are also discussed in [15], where a survey of navigation limits in the Arctic region is presented. Augmentation system coverage and control station distribution are two limiting factors for the accuracy of GNSS-based navigation at high latitudes [16; 17]. Finally, Galileo opportunities and challenges for Arctic navigation are summarized in [18]. Three months of continuous data were collected from the Galileo E6B signal and used to generate summary statistics, such as the average TTRD. The unique experimental setup and the long duration of the experiment allow the reliable characterization of the HAS performance under challenging conditions. The Septentrio PolaRx5S was used to collect the E6B raw bits and provide information on the different decoding operations performed for the recovery of the HAS message. Different metrics were then computed from the E6B raw bits and the other measurements provided by the Septentrio receiver. It is worth underlining that, during the data collection, only dummy messages were broadcast.