Eloran

eLORAN, or enhanced LORAN, is a terrestrial radio navigation system that provides position, navigation, and timing information using networks of ground-based transmitters. It was developed as an upgraded successor to LORAN-C and is intended to serve as an independent backup to satellite-based GNSS systems such as GPS, Galileo, and GLONASS, improving resilience for maritime, aviation, and land users.

The system operates with transmitters arranged in chains, including a master station and multiple secondary stations that broadcast synchronized low-frequency signals. A receiver determines a position by measuring the differences in signal arrival times from at least two transmitters, producing hyperbolic lines of position that intersect to yield a fix. In addition to positioning, eLORAN provides precise timing references that can support other critical infrastructure.

Modern eLORAN implementations include digital modulation, improved timing accuracy, and higher robustness of transmissions. These enhancements aim to deliver reliable coverage across oceans, coastlines, and remote areas, and to offer greater resilience to certain forms of interference or jamming compared with some GNSS services, although no system is completely immune to disruption.

Status and usage vary by country. After LORAN-C was decommissioned in many regions, select nations pursued eLORAN as a national backup, maintained pilot networks, or paused operations based on policy, funding, and assessments of GNSS vulnerability. In practice, eLORAN is positioned as a complementary technology to GNSS, enabling continued navigation and timing services in the event of GNSS degradation or outage.