eLORAN Applications

Aviation: Aviation navigation services support aircraft operations in the departure, en-route, and approach and landing phases of flight. In the US, Loran C has long been approved for use by aircraft with certified receivers, flying en-route and making departures and arrivals, but not for the critical approach and landing phases. The much higher accuracy, availability, integrity, and continuity of eLORAN does meet the specifications for each of these phases allowing eLORAN to support aircraft operations from gate-to-gate.

Maritime: The world’s shipping industry is experiencing strong growth, which is expected to continue. Ships are getting larger and faster, sea-lanes are becoming more crowded, and crews are increasingly relying on electronic navigation systems to operate in this environment. The newly proposed concept of e Navigation will improve safety, security, and protection of the marine environment as well as potentially reducing costs. It will provide bridge officers with all the information they need on a single display. In order to make these critical e-navigation services available, the system will require a supply of position and timing data of exceptionally high accuracy and reliability. This information will come principally from GNSS. But GNSS alone cannot be guaranteed to meet the availability and reliability required. Uniquely, the combination of GNSS and eLORAN will do so, with the two systems operating independently of one another, but providing a single combined output data stream. Thus, eLORAN is the key that will enable e Navigation to deliver its full range of benefits and maintain safety through redundancy. The high availability achieved could also lead to a reduction in the number of traditional physical aids to navigation - lights and buoys – with potentially substantial cost savings.

Land Mobile: eLORAN will provide PNT data for a variety of land mobile applications, working alongside GNSS. However, it can also provide the e-Loran compass capability to determine the heading of a vehicle even when it is stationary. eLORAN, via the data channel, can authenticate its own and GNSS data when it is used for toll collection or vehicle monitoring. It is perhaps on land that eLORAN’s greatly enhanced immunity to jamming compared to that of GNSS will prove to be of the greatest value. eLORAN employs high-powered transmitters, so the signals reaching receivers are of much greater strength than those of GNSS and require much more power to jam. Given that radiating significant power efficiently at the low frequency and long wavelength of Loran requires large antenna structures, it is extremely difficult to produce a signal that could jam an eLORAN signal over more than a very small local area. In contrast, jamming a GNSS signal even over a whole city (for example, to block a road pricing system) is not very technically demanding. A further important benefit of eLORAN’s low frequency signals is their ability to penetrate into places where GNSS signals either cannot be received at all, or where they are intermittent or inaccurate. These include the urban canyons in the centers of major cities. Loran signals have been shown to penetrate reliably into steel shipping containers, refrigerated vehicles and storage warehouses . This ability has led to the development of systems that track items either of high-value or whose safe and timely delivery must be guaranteed. The tracking of hazardous cargoes also demands the consistent updates and high availability of eLORAN-based systems.

Location Based Services: eLORAN services will also deliver PNT data to support numerous location based services (i.e. personal applications). eLORAN’s ability to penetrate into urban canyons and building can assist service providers in meeting the evolving PNT performance requirements including those for E-911(US) or E-112 (Europe) response systems. Other applications include, but are not limited to, location-based encryption systems, geo-fencing, weather balloon tracking, offender tracking, and location-based billing. The performance standards for these applications, as with those for any land mobile applications, need to be assessed and optimized for user specific applications.

Time & Frequency: Using GNSS is now the principal method of recovering UTC time world-wide. GNSS is extensively employed as a time source in the telecommunications and many other industries. It provides time with an accuracy of 5 – 100 nanoseconds. eLORAN is a viable alternative source of time, since its transmissions are precisely synchronized to UTC. The data channel carries messages that receivers use to identify the timing of each individual eLORAN pulse from each station. Other messages on this channel also correct for small variations caused by propagation delays. Employing them allows absolute UTC time to be recovered with an accuracy of 50 nanoseconds. Thus an eLORAN timing receiver can serve as a reference clock, a primary source of time, or as an alternative to GNSS; combined GNSS-Loran timing receivers are available commercially. A particular advantage of eLORAN over GNSS is the availability of its signals indoors. This avoids the need to install an outside antenna with a clear view of the sky, something that can be particularly difficult (and even expensive) in downtown city-center locations and high-rise buildings. eLORAN is also used as a source of precise frequency; frequency is the rate of change of a clock. eLORAN timing receivers have been shown to meet the Stratum 1 (1x10^-11) frequency standard, even without differential corrections. And this can be done with an indoor antenna!