Vector H200 processes L1 GPS and GLONASS signals to deliver precise heading, greater positioning reliability, and better performance in challenging environments, Hemisphere GNSS said. Through using two separate antennas, Hemisphere GNSS’ patented Vector technology computes the heading and pitch or roll angle while stationary or in motion. Vector H200 can compute heading accuracy to 0.02 degrees using a 5-meter antenna separation. A variety of differential correction methods also make it possible for Vector H200 to provide sub-meter to centimeter position accuracy.

Marine industry developers can maximize performance by integrating Vector H200 into their systems for hydrographic and bathymetric surveys, auto-pilots, dredging, and buoys. For land applications, Vector H200 is ideal for aligning cameras, antennas and projectiles, and for machine control applications in agriculture, construction, and mining.

“System integrators have a lot to gain from Vector H200’s powerful combination of navigation and machine control orientation capabilities,” said Ron Ramsaran, Sr. Product Marketing Manager at Hemisphere GNSS. “They will appreciate the performance and value from such a small board package.”

Vector H200 supports SBAS, L-Band and RTK differential positioning solutions and features our exclusive SureTrack technology optimizing the use of GPS and GLONASS signals. Hemisphere GNSS offers precise GNSS antennas to fit a variety of Vector H200 applications.

The C-Tides suite combines the vertical accuracy of C-Nav’s GNSS Precise Point Positioning service with the latest advanced ocean and coastal tides models, the company said.

C-Tides Online features real-time filters and vessel dynamics, a choice of worldwide Mean Sea Surface or regional reference frame models, and tidal prediction for mission planning.

C-Tides Offline utilities include data smoothing and outlier rejection, harmonic analysis, Doodson X0 filter, and a LAT option.

“It’s been a privilege working with our academic partners to develop what is probably the worlds’ most advanced real-time GNSS tide solution,” said Russell Morton, C-Nav head of development.

C-Tides is a fully supported C-Nav utility. The results are suitable for combining with other suitably calibrated vertical components to achieve IHO SP44 Order 1 or better.

The R330 GNSS receiver combines the functionality and front panel display of all previous R-series products. Customers can start with sub-meter positioning accuracy and upgrade the receiver with subscriptions that add functionality and improves performance capability to centimeter-level accuracy. To provide the most reliable solutions, R330 is capable of tracking multiple frequencies and multiple constellations including GPS and GLONASS. Users can easily switch between the various DGPS correction options without any downtime. The R330 GNSS receiver is compatible with many of the Hemisphere GNSS’ multi-frequency antennas.

The small, rugged receiver includes a display and status indicators for a user-friendly experience, Hemisphere GNSS said. A standard USB flash drive can be used for data logging.

“The functionality and performance of the R330 receiver can be custom-fit to positioning applications such as pipeline, marine, and volumetric surveys, GIS mapping, vehicle tracking, machine control, meter monitoring and many others,” said Ron Ramsaran, senior product marketing manager at Hemisphere GNSS. “R330 customers will benefit from the reliability, value, and upgrade options that can be added to meet changing needs.”

R330 features Hemisphere GNSS’ exclusive Eclipse SureTrack technology, enabling a more robust RTK solution with fewer dropouts in congested environments and a fast reacquisition when dropouts do occur. Long-range RTK baselines of up to 50 km are achievable with R330.

The R330 GNSS receiver will be available in June through the Hemisphere GNSS Precision Products global dealer network.

Using the MR-1 receiver and Topcon’s MG-A8 antenna, the system provides “centimeter-accurate RTK positioning and better than 1/10 of a degree heading accuracy in challenging environments,” said Doug Langen, TPS GNSS product manager. “The rugged MR-1 receiver is water and dustproof and operates at a robust operational temperature range of -40°C to 75°C.”

When combined with Topcon’s Quartz Lock Loop technology, the MR-1 offers continuous operation during “extreme vibration and shock, typical of intense dynamic environments,” he said.

The MG-A8 antenna of the MR-1 Heading System is designed for moving platforms and provides multipath rejection. It also offers increased resistance to near-band interference from satellite communications systems commonly found in marine applications.

Additional information is available at www.topconoemsolutions.com.

“Time and Navigation is an ambitious exhibit because it traces the development of very complicated technologies and makes us think about a subject we now take for granted,” said Gen. J.R. “Jack” Dailey, director of the museum. “Today, the technology needed to accurately navigate is integrated into mobile computers and phones: hundreds of years of technological heritage tell your handheld device where you are in a seamless manner. This opens up new possibilities and challenging questions for the next generation of scientists and explorers who visit this exhibit to start thinking about.”

Don Jewell discussed the exhibit in depth in his March Defense PNT column.

The gallery is organized into five sections and spans three centuries of efforts to travel on Earth and through the solar system. In each section the visitor will learn about pioneer navigators facing myriad issues, but one challenge always stands out: the need to know accurate time.

Sections

This timekeeper was the first American-made marine timekeeper taken to sea. William Cranch Bond, a 23-year-old Boston clockmaker, crafted it during the War of 1812.

Navigating at Sea is an immersive environment that suggests a walk through a 19th-century sailing vessel. Visitors will learn how centuries ago navigators at sea relied on chronometers and measurements of celestial objects to determine location. This section includes a mariner’s astrolabe, dating from 1602; a Ramsden sextant and dividing engine; several chronometers; a model of Galileo’s pendulum clock; and the earliest sea-going marine chronometer made in the United States, produced by Bostonian William Cranch Bond during the War of 1812. It also features an interactive display that allows visitors to use a sextant to navigate with the stars.

Navigating in the Air relates how air navigators struggled with greater speeds, worse weather and more cramped conditions than their sea-going predecessors. It tells the story of the innovations that overcame these challenges, as represented the gallery’s largest artifact, the Lockheed Vega “Winnie Mae,” flown by Wiley Post and Harold Gatty, shattering the around-the-world record in 1931. Visitors will learn that Charles Lindbergh required navigational tutoring after he flew to Paris and how he paved the way for a new system of navigation in the process. A personal account by a WWII navigator highlights wartime innovations. This section ends with an explanation of how clocks with tiny quartz crystals opened an entirely new era of navigation in the form of LORAN (LOng RAnge Navigation).

Wiley Post’s Winnie Mae circled the globe two times, shattering previous records. The first time was in 1931 with Weems associate Harold Gatty as lead navigator. The second was a solo flight in 1933 assisted by “Mechanical Mike,” one of the world’s first practical autopilots.

Navigating in Space traces how teams of talented engineers invented the new science of space navigation using star sightings, precise timing and radio communications. This section includes an Apollo sextant, a space shuttle star tracker, timing equipment used at a ground tracking station and a flight spare (duplicate spacecraft) of Mariner 10, the first spacecraft to reach Mercury.

Inventing Satellite Navigation describes how traveling in space inspired plans to navigate from space. Innovators found that time from precise clocks on satellites, transmitted by radio signals, could be used to determine location. The U.S. military combined several breakthroughs to create the Global Positioning System. Some of the artifacts in this section are the NIST-7 atomic clock that served as the U.S. time standard in the 1990s, the navigation system from the nuclear submarine U.S.S. Alabama, a satellite from the Transit system used for global navigation before GPS and a test satellite global navigation built at the Naval Research Laboratory.

An official DARPA photograph of Stanley at the 2005 DARPA Grand Challenge. Stanley, created by the Stanford University Racing Team, won the race.

Navigation for Everyone tells the stories of real people — a fireman, a farmer and a student — who use modern navigation technology in their everyday lives. It also addresses what might come next: the story is not over yet and many new technologies are being developed. This section includes a disassembled mobile phone with a diagram showing all its parts and depicts how hundreds of years of navigation technology are now in the palm of a user’s hand. It also features “Stanley,” the robot car that won the 2005 Grand Challenge, a robot race sponsored by the Defense Advanced Research Projects Agency.

The exhibition is made possible through the support of Northrop Grumman Corporation; Exelis Inc.; Honeywell; National Geospatial-Intelligence Agency; U.S. Department of Transportation; Magellan GPS; National Coordination Office for Space-Based Positioning, Navigation and Timing; Rockwell Collins; and the Institute of Navigation.

The National Air and Space Museum building on the National Mall in Washington, D.C., is located at Sixth Street and Independence Avenue S.W. The museum’s Steven F. Udvar-Hazy Center is located in Chantilly, Va., near Washington Dulles International Airport. The National Museum of American History collects, preserves and displays American heritage in the areas of social, political, cultural, scientific and military history.

An overview of the work of the General Lighthouse Authorities of the United Kingdom and Ireland on the implementation of Enhanced Loran Initial Operational Capability (IOC) in the waters around Great Britain. eLoran is the latest in the longstanding and proven series of low-frequency, LOng-RAnge Navigation systems. It evolved from Loran-C in response to the 2001 Volpe Report on GPS vulnerability. It vastly improves upon previous Loran systems with updated equipment, signals, and operating procedures.

By Paul Williams and Chris Hargreaves

GPS/GNSS is everywhere! It is used in many ship’s systems (Figure 1), but it is vulnerable to interference both intentional and unintentional.

Its output is displayed on the  electronic chart display and information system; is transmitted to other vessels using the Automatic Identification System (AIS); is used to calibrate the gyro compass; is used in the radar; is connected to the digital selective calling, its reported position transmitted at the push of the emergency button for search-and-rescue; is in the vessel data recorder, the dynamic positioning system, surveying equipment, the ship’s entertainment system for aiming the satellite dish; and it even synchronizes the ship’s clocks!

28 days worth of ship-traffic data for the Strait of Dover.

GNSS is also used in marine Aids-to-Navigation (AtoN) provision, for deploying buoys and lights, AIS transponders, and AtoN position monitoring, and its precise timing capabilities are used to synchronise the lights along an approach channel to improve conspicuity.

GNSS (effectively GPS) has become the primary Aid-to-Navigation (AtoN) used by all professional and most other mariners. The vulnerability of GNSS to space weather and interference (unintentional and criminal jamming) means that a backup system is needed to achieve resilient Position, Navigation, and Timing (PNT) for e-Navigation. Though the probability of losing GNSS may be low, the consequential impact could be very high, and maintaining an appropriate balance of physical and radionavigation AtoNs is vital for e-Navigation.

Figure 1. GPS is used in many ship’s systems.

The International Maritime Organisation seeks to develop a strategic vision for e-Navigation, integrating existing and new navigational tools in an all-embracing system, contributing to enhanced navigational safety and environmental protection, while reducing the burden on the navigator. One of IMO’s requirements for e-Navigation is that it should be resilient — robust, reliable and dependable.

The General Lighthouse Authorities of the United Kingdom and Ireland (GLAs) have the statutory responsibility to provide marine AtoNs around the coast of England, Wales, Ireland, and Scotland. It has become clear over recent years that if the GLA chose to implement eLoran, it could rationalize its physical AtoN infrastructure, removing some lights and other physical aids, and on balance actually reduce costs by implementing eLoran. Indeed, compared to other possible resilient PNT options such as GNSS hardening, radar absolute positioning, increasing physical AtoN provision, eLoran would save the GLAs £25.6M over a nominal system lifespan of 10 years from the introduction of e-Navigation services in 2018 to 2028.

Not So Old-Fashioned. How does the new eLoran differ from the old, outdated, Loran-C system? The core signal of eLoran is pretty much the same as Loran-C, but tolerances have been tightened up. Things like carrier zero crossing points, half-cycle peaks, ECDs, transmission timing, signal power, signal availability, power supply resilience have all been upgraded, taking advantage of improvements in technology allowing us to better appease the so-called four horsemen of navigation: accuracy, availability, continuity, and integrity.

SAM control is a thing of the past, and eLoran transmitters are synchronised directly to UTC. This means that their times of transmission can be predicted. Having stations independently synchronised to UTC means that the mariner no longer has to rely on old-fashioned hyperbolic navigation. Charts with hyperbolic lines of position on them are also a thing of the past. A modern eLoran receiver works just like a GPS receiver, employing signals from all available transmitters in its position solution. With GPS those transmitters are moving in space; in eLoran the transmitters are fixed onto the surface of the Earth.

Reelektronika LORADD receiver, only 3 centimeters tall.

Modern receivers are small (photo). They use off-the-shelf, high-performance processors, and the receiver is written in software, allowing a lot of flexibility.

Three transmitters are sufficient to give you position; four or preferably five signals are better for integrity. But for timing and frequency applications you only need one transmitter. The Anthorn station in the UK can cover the entire UK and Ireland with a radio signal that has stability enough to satisfy the Stratum 1 frequency source requirement for steering the clocks of telecom networks, and Anthorn has not even been upgraded to full eLoran standard yet!

One of the big differences between Loran-C and eLoran is that eLoran now has a data channel. Some of the Loran pulses of each pulse group are modulated so that data can be sent over the 100kHz signal. This allows service providers to send integrity alerts, and application-specific data, like UTC time, and differential-Loran (DLoran) and DGPS corrections. In Europe this is implemented by the already internationally standardised Eurofix system.

A parallel can be drawn with GPS signals, which contain a navigation component (pseudorandom noise code and/or carrier phase) and modulated data. Some options for data channel technology are still evolving with 1500 bits per second demonstrated, and 3000 bps possible. That may not sound very much to salt-of-the-earth communications engineers, but for Loran it’s pretty impressive, especially when you consider prototype attempts at Loran data communications in the past have been limited to 30 to 250 bps.

Maritime Applications Services

How do we apply eLoran to something like the maritime application of port approach? It is important to remember that the receiver operates by measuring how long it takes a groundwave radio signal to travel over the surface of the earth. An eLoran receiver assumes that the world is made entirely of seawater, for which it has a very accurate propagation model built in. The receiver does not, and indeed cannot, know about any land along the propagation path; and land slows the signal down, perhaps by as much as a few microseconds, over typical propagation distances.

So the service provider must survey the effects of the land masses in the area of coverage. The Additional Secondary Factors (ASFs) of all the stations across the proposed service area are therefore mapped. The ASF survey is a once-and-for-all task, but it needs to be done and the ASFs published. In the old days, hyperbolic lines would be “grid warped,” or tables would be published on paper for the navigator to enter values manually. But with modern eLoran receivers containing large amounts of memory, quite detailed ASF maps can be stored in the mariner’s receiver.

ASFs depend on the electrical conductivity of the surface over which the eLoran signal travels. The conductivity changes with the constitution and moisture content of the earth. This means that the ASF along a path varies over a period of time —perhaps by as much as a few hundred nanoseconds over a year. Because the ASFs in a receiver are fixed, a method is needed to correct for this temporal ASF variation. In order to monitor this variation, a reference station is installed close to the harbor or point of use of the eLoran service. This DLoran reference station measures the temporal changes in the signals’ arrival times due to changing ASFs, transmitter variations, and weather effects.

The phrase “reference station” conjures up images of expensive buildings, amenities, and hordes of personnel and associated support services. However, a DLoran reference station is a small box sitting in the corner of a room connected to a small eLoran receive antenna on the roof, and to the Internet. It sends differential corrections over the Internet to an eLoran transmitter, which then broadcasts them to the mariner’s receiver over the Loran Data Channel, for example Eurofix.

Note that a DLoran reference station does not transmit a radio signal. It does not need a transmitter itself; it uses the Internet and the eLoran signal to disseminate its real time data. The mariner uses the same eLoran receiver to receive both the navigation signal AND the differential corrections.

So the process is: map ASFs once; run a reference station; and broadcast corrections. That’s it! With good signal-to-noise ratio and transmitter geometry, 10-meter or better accuracy can be obtained.

Measuring ASFs

The GLA have had the ability to measure ASFs for several years, using a combination of commercial hardware and proprietary software (Figure 2).

Figure 2. GLA-produced software for ASF survey, processing, and validation.

The software, written in Matlab, shows a real-time plot of the survey as it progresses. The ASF values are color-coded according to magnitude. The software can also process the ASF data once it has been measured, to get the best performance out of it. The real-time capabilities of the software allow the determination of the quality of the data while aboard the ship, rather than having to wait until back in the laboratory. Statistical analysis of the data can also show where the ship should go to gather more data in a particular area.

Once the survey is complete, the software can be used to generate interpolated grids of ASF data — the most convenient and accurate form of ASF data storage.

It is important with any scientific or engineering measurement to establish the error on that measurement. The same can be said of ASFs, and so the software can calculate the error bounds on ASF measurements. This “ASF error” data can again be published in grid form alongside the ASF database. This allows it to be used as one component of an Integrity Equation, implemented within the mariner’s receiver, to calculate Horizontal Protection Level (HPL).

After processing, the ASF data should be validated by performing a harbor approach or other maneuver that requires a particular positioning accuracy. For this, the software can be switched to “Validation” mode. Once the validation is successful, the data can be output in a publication format (RTCM SC-127 format for example).

The plot in Figure 2 shows part of an ASF database for Harwich and Felixstowe, major ports on the east coast of the UK. Using this data and DLoran in the Harwich and Felixstowe approach provides 10-meter (95 percent) positioning accuracy.

UK eLoran Prototype

This prototype eLoran system works alongside GPS. It has been in operation 24 hours a day since May 2010. It is “prototype” because it demonstrates the concept of eLoran using signals from existing Loran-C stations in Norway, the Faroe Islands, Germany, and France plus the UK’s station at Anthorn; see Figure 3.

Figure 3. Relevant European Loran-C stations for prototype eLoran.

These stations, together with ASF measurements and DLoran, can deliver a high-precision eLoran service in ports where 10-20 meter accuracy is needed, across the area enclosed by the green contour in Figure 4.

Figure 4. Coverage of prototype eLoran over the UK and Ireland.

It is very impressive, yet the full availability and accuracy benefits of eLoran are still to come as these stations are eventually upgraded to full eLoran capability. And for the last year or so, the GLA have begun to move beyond the confines of the Harwich and Felixstowe approaches and implement initial eLoran services in other regions around the GLA service area.

The GLA aim to do this in two stages. In the first stage Initial Operational Capability (IOC) service will be installed by mid-2014, with the second stage Full Operational Capability (FOC) service covering all major ports in the UK and Ireland, plus Traffic Separation Schemes, installed by 2019 or so in time for e-Navigation.

Initial Operational Capability

IOC involves upgrading the installation at Harwich and Felixstowe and new installations in the approaches to another six of the busiest ports in the UK: Aberdeen, Grangemouth, Middlesbrough, Immingham, Tilbury, and Dover. For each of these areas an ASF survey and a DLoran reference station will be required.

The corrections for these reference stations will be broadcast using the Anthorn Loran Data Channel. There is also the need for a Monitoring and Control System for the network of DLoran Reference Stations, and it is envisaged that this will be based in Harwich. Figure 5 illustrates the architecture of the Initial Operational Capability system. The diagram shows the major components: eLoran transmitter, DLoran reference station network, monitor, and control system. Also shown are the interfaces between the components, which provide not only operational data but also include the ability to monitor the integrity of the system. Also note that the Loran Data Channel is capable of supporting third-party messaging applications using a client “logon” facility. This is already being done at Anthorn.

Figure 5. The architecture of the UK GLA’s eLoran Initial Operational Capability.

The European tender process for seven operational reference stations and the control system is almost complete.

The aim of IOC is to provide areas for demonstrations and trials, so that the mariner can gain experience of the system and its capabilities and provide feedback to the GLA on its performance.

eLoran at the Port of Dover

In the absence of the final operational reference stations, the GLA decided to perform an early implementation using prototype equipment that was already available at the GLA.   The choice for this implementation was obvious: the iconic Port of Dover, a major port on the southeast coast of the UK and the Dover Strait, one of the busiest seaways in the world. Some 500-plus vessels travel through the Strait each day on their way to or from the North Sea region; see Opening Figure.

The GLA have, with the agreement of Port of Dover Operations, installed a prototype DLoran Reference Station within the port’s Terminal Control building. The roof of the building is an ideal location for the reference station receiver antenna as the location demonstrates low noise in the eLoran band and has easy access to mains power, cable runs, antenna mounts, and Internet access.

The ASF survey took place in March 2012, and covers the area outlined by the yellow polygon in Figure 6.

Figure 6. Area of March 2012 ASF survey.

Accuracy Performance Validation

Once the ASFs had been measured and the prototype reference station installed, the performance needed to be tested. This was accomplished through a validation run of the vessel through the area.

Figure 7 shows a screenshot of the GLA ASF measurement software running in validation mode. The colored track shows the path of the vessel, with the color indicating the positioning error compared to differential GPS. The vessel travels through an area of extrapolated and interpolated ASF data, so the positioning error at the northern end of the track is higher than the lower end of the track.

Figure 7. Screenshot of GLA ASF measurement software running in validation mode.

Figure 8 shows a comparison of eLoran positioning against DGPS positioning along the route as a scatter plot. The associated Cumulative Distribution Function (CDF) is shown on the right of the diagram. From this it can be seen that the positioning accuracy obtained along this particular route was 12.5 meters (95 percent).

Figure 8. eLoran positioning accuracy scatter plot and cumulative distribution function of positioning error. Accuracy: 12.5 m (95%)

Dover to Calais Ferry Installation. Further validation and demonstrations will take place aboard a cross-Channel ferry. P&O Ferries in the UK has installed a receiver aboard their vessel, The Spirit of Britain. This relatively new vessel is one of the largest passenger ships to operate along the iconic Dover to Calais route. Data will be collected and feedback obtained on the eLoran service’s performance over the coming months.

Other Areas

The GLA continue their work towards IOC-level eLoran. Dover was the first port of call for the GLA eLoran Initial Operational Capability — the ASFs have been mapped and a prototype DLoran reference station has been installed.  The final operational DLoran reference stations should be available this time next year.

The next area the GLA have concentrated upon is the Thames Estuary up to Tilbury. Although the GLA have not yet installed a permanent DLoran reference station, the ASF survey was performed in November 2012 using a temporary reference station installed at Medway. Along the route shown in Figure 9, a validation trial demonstrated 8.3 meters (95 percent) accuracy (Figure 10). The GLA have also recently surveyed the River Humber, including its approaches, up to the port of Hull. The data is currently in the process of being validated.

Figure 9. ASF map validation route from the port of Medway heading out of the River Thames estuary.

Figure 10. eLoran positioning accuracy scatter plot and cumulative distribution function of positioning error. Accuracy: 8.3 m (95%).

Status and Next Steps

The next steps are to continue the implementation of IOC eLoran at the remaining port approaches for this phase. It is the aim that all ASF surveys will have been performed by the middle of 2014 in readiness for the installation of the operational DLoran reference stations at each candidate port. Licence agreements are being established with the various port authorities involved in order to allow this.

All ports that have been approached are positive and are keen to assist in the GLA eLoran implementations. eLoran noise surveys have been performed at all ports and locations for all DLoran reference stations have been found.

The Port of Dover has prototype eLoran up and running and has demonstrated 12.5-meter (95 percent) accuracy during the limited validation performed so far; however, further validation continues aboard the Spirit of Britain ferry.

The Thames Estuary ASF Survey has been performed, and 8-meter (95 percent) accuracy has been demonstrated in the area. The River Humber and its approaches have also been surveyed with validation in progress.

IOC-level DLoran reference stations should be available mid-2014, ready for installation.

The methods and processes employed during this work will be proposed for inclusion within the next version of the eLoran receiver Minimum Performance Specification as determined by Radio Technical Commission for Maritime Services (RTCM) Special Committee 27.  These include techniques and algorithms used for ASF measurement processing, the preferred ASF file format, guidelines on the usage of ASF data, and integrity computation.

Acknowledgments

The GLA acknowledge the assistance of the crew of THV Alert, the Dover Harbour Board, Peel Ports (Medway), Associated British Ports (Humber), Aberdeen Harbour Authority, Forth Ports, PD Ports (Middlesbrough).

This article is based on a presentation made at the Institute of Navigation International Technical Meeting, January 2013, in San Diego, California.

Paul Williams is a principal development engineer with the Research and Radionavigation Directorate of the GLA, and technical lead of the GLA’s eLoran Work Programme, responsible for the ongoing roll-out of the GLA’s eLoran Initial Operational Capability (IOC). He holds a Ph.D. in electronic engineering from the University of Wales.

Chris Hargreaves is is a research and development engineer with the Research and Radionavigation Directorate Directorate of the GLA. His work focuses on eLoran in measurement trials, software development, and data analysis. He holds a masters’ degrees in mathematics and physics from the University of Durham and in navigation technology from the University of Nottingham.

America’s First Marine Chronometer.

Bradford W. Parkinson, professor of Aeronautics and Astronautics Emeritus at Stanford University, discussed “GPS for Humanity — The Stealth Utility” at a special Smithsonian event Thursday, March 21. If you missed his talk, you can view it now on UStream.

Parkinson’s lecture at the National Air and Space Museum in Washington, D.C., was part of the introduction of the new Smithsonian exhibition Time and Navigation: The Untold Story of Getting from Here to There, which opens April 12. Don Jewell, GPS World’s contributing editor for Defense, discusses the exhibit in his February column.

According to the Smithsonian, for centuries, nations have invested enormous resources to determine time and place for geopolitical reasons, and their research has changed people’s view of the world. Advanced technology that was once available only to the military has become commonplace in car dashboards, cell phones and a growing number of other portable devices of daily life. The Time and Navigation exhibit explores how revolutions in timekeeping over three centuries have influenced how people find their way. It is organized into five sections: Navigating at Sea; Navigating in the Air; Navigating in Space; Inventing Satellite Navigation; and Navigation for Everyone.

Bygrave Position-Line Slide Rule.

Andrew Johnston (geographer, Center for Earth and Planetary Studies, National Air and Space Museum) gave a presentation about the exhibit at ION GNSS in Nashville, Tennessee.

In the 1970s, Parkinson was the chief architect and original program director for GPS. In his lecture, he will present the history, applications, and future of GPS and the GNSS. Central to operation of GPS is the relationship between time and navigation, and GPS will be explored in the Time and Navigation exhibit.

The ground-based eLoran system provides alternative position and timing signals for improved navigational safety. The Dover area, the world’s busiest shipping lane, is the first in the world to achieve this initial operational capability (IOC) for shipping companies operating both passenger and cargo services.

Today’s announcement represents the first of up to seven eLoran installations to be implemented along the East Coast of the United Kingdom. The Thames Estuary and approaches up to Tilbury, the Humber Estuary and approaches, and the ports of Middlesbrough, Grangemouth and Aberdeen will all benefit from new installations, and the prototype service at Harwich and Felixstowe will be upgraded, the GLA said.

Although primarily intended as a maritime aid to navigation, eLoran could become a cost-effective backup for a wide range of applications that are becoming increasingly reliant on the position and timing information provided by satellite systems.

“Our primary concern at the GLA is for the safety of mariners,” said Captain Ian McNaught, Chief Executive of Trinity House. “But signals from eLoran transmitters could also provide essential backup to telecommunications, smart grid and high frequency trading systems vulnerable to jamming by natural or deliberate means. We encourage ship owners and mariners to assess eLoran in this region and provide feedback to the GLA on its performance.”

P&O Ferries has installed an eLoran receiver on its new vessel Spirit of Britain. She will be based at Dover and is one of the largest passenger ships the busy Dover/Calais route has ever seen.

“Accurate real-time positional information is essential for the safe navigation of ships with modern electronic charts,” Captain Simon Richardson, head of Safety Management at P&O Ferries, said. “Satellite navigation systems are vulnerable to degradation of signal strength and our ships have also experienced occasional loss of signal. We welcome the development of a robust alternative to provide redundancy in real-time positional information and we see eLoran as the most effective solution to countering the problem.”

Commenting on the announcement Stephen Hammond, Minister for Shipping, said, “I congratulate the General Lighthouse Authorities on this initiative that seeks to improve navigational safety in what is the busiest shipping channel in the world, through the development and deployment of technology. I look forward to receiving reports of its effectiveness.”