NTT and FURUNO ELECTRIC CO. have developed a receiver for GPS and other global navigation satellite systems (GNSS) that significantly improves time-synchronization accuracy in areas with severe reception conditions such as among buildings and in mountainous areas.
NTT said its new satellite signal selection algorithm and a time synchronization GNSS receiver from FURUNO makes it possible to use multi-path satellite signals (reflected or diffracted from buildings and other structures), which previously inhibited accuracy of time synchronization. In a real multi-path reception test environment, time error was reduced to approximately 1/5 of earlier values. This is a remarkable result in that it promises to enable time synchronization accuracy close to that obtained in open-sky reception environments with no obstructions, even in environments previously considered poor and unsuitable for accurate time synchronization, such as among buildings or in mountainous areas.
FURUNO plans to begin sales of their new GF-88 series time synchronization GNSS receivers incorporating this new technology in April of 2019. Potential applications include 4G/5G mobile base stations, financial trading, power grids, and data centers.
http://www.ntt.co.jp/news2018/1810e/181023a.html