Boaters Benefit From a New Kind of Space Race

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Star Wars

World economic powers have joined a new kind of space race.
And boaters may be the ultimate winner.

The United States and Russia have already claimed first and second place in the race to build satellite-navigation systems, respectively, but the playoff for third place is still underway, with China leaping ahead of the European Union. 

Galileo launch

Galileo—the European system—was a late starter in the satnav game. Several initial proposals were whittled down to one in 1999, but it was 2003 before it got the official go-ahead—more than a quarter of a century behind GPS and the Russian Glonass. Even so, early predictions were that it would be operational by 2008. 

Unfortunately, Galileo’s advantage of being designed and built with 21st-century technology was offset by constant bickering between the various countries that make up the European Union, so 2008 came and went with only two test-bed satellites in orbit. Meanwhile, the Chinese managed to build a fully functioning satellite navigation system in just five years. 

So what does all this mean for your weekend plan to take the boat to Roche Harbor? Well even the rosy descriptons of GPS on the government’s official Web site (www.gps.gov) don’t mask the situation. It doesn’t take a rocket scientist to figure out that all seven operational satellites in Block IIR(M), a modernization effort that took place from 2005 to 2009, are already headed out of date (the satellites have a 7½-year lifespan). And all GPS-related maintenance and upgrade efforts going forward are at the mercurial whim of stateside rocket programs and government funding. The bottom line: Why not use other global systems to help maintain accurate positioning? The data is there for the receiving, and the redundancy is built in (See “Failsafe?” below).

Failsafe?

The idea that an entire satellite system might suddenly fail seems far-fetched.

But on April 1 last year, it happened.

At 5:15 pm eastern time, all but three of the 24 operational Glonass satellites began transmitting false data. Glonass receivers all over the world were affected: Some showed positions that were up to 108 nautical miles adrift.

Two satellites recovered within an hour, but by that time, the three that were initially unaffected had succumbed, and some of them did not recover until 2:30 am eastern time the following day—a system “outage” that lasted more than ten hours.

It turned out that the problem lay in computer software that wrongly predicted the positions of the satellites.

Contradictory explanations have emerged as to why it took so long for the problem to be rectified. Some sources say that it was because it took that long to find and fix the bug. Another, more plausible explanation is that corrected data had to be uploaded to each satellite individually, when it passed within range of a control center.

“Incorporating different GNSS access within products ensures connectivity throughout the world and helps safeguard against loss of signal when an individual system is not operating correctly such as the recent 48-hour GLONASS outage,” says Louis Chemi, executive vice president and managing director of  the recreational marine division for Navico, maker of Simrad, Lowrance, and B&G electronics brands. “Connectivity to more satellite systems increases position accuracy even in situations where weather or obscured line of sight is an issue. For the Simrad Yachting, Lowrance, and B&G brands, it is important to us that our customers can use their system anywhere on the globe and that they have the peace of mind that they know their position and have maximum position awareness regardless of what GNSS system is mandated and where they boat.”

Galileo showed promise, only to falter. Four prototype In-Orbit Validation (IOV) satellites were launched in 2011 and 2012. One has since been taken out of service because of a faulty antenna, but not before they had demonstrated that the system really did work. With the financial and political wrangling apparently over, the European Space Agency was able to announce that, “This In-Orbit Validation phase is now being followed by additional satellite launches to reach Initial Operational Capability around mid-decade.” The plan was that the four IOV satellites would be joined by 14 Full-Operational Capability (FOC) satellites by 2014, and that further satellites would be launched in groups of four to build up to a full constellation of 30 satellites by the end of the decade. 

But Galileo is still bedeviled by technical issues. The first pair of FOC satellites were supposed to be launched in 2013, but weren’t delivered to the launch site until May of last year. And when they finally made it into space, in August, it was found that a malfunction in the Russian-built rocket that launched them sent the satellites into the wrong orbits—elliptical instead of circular, and wandering between 5,130 nautical miles too low to 1,450 nautical miles too high.

One of the two has since been “nudged” into a usable orbit, and a similar procedure is underway to recover the other. But it’s not a perfect solution: The salvage operation used up three quarters of the satellite’s onboard fuel reserves—leaving barely enough to last it through the 12 years of its designed life expectancy—but still didn’t get it back into its intended orbit. Experts are already warning that this may cause some receivers to have problems locking on to the errant satellites.

Galileo constellation

The official estimate—that Galileo will achieve Full Operational Capability by the end of this decade—seems optimistic. It’s still achievable, but given its track record so far, it is looking increasingly unlikely.

The Chinese government got its system running much more quickly. It approved proposals for the Beidou 2—named after the Chinese name for the constellation that we know as the Big Dipper—in 2006, and by 2011 it was up and running, providing navigators in and around China with position fixes that the Chinese claim to be as good or better than those achieved by GPS both in position acquisition and accuracy.

Beidou 2 is almost unheard of in the western world, but its coverage now extends from Russia to New Zealand, and the International Maritime Organization has recognized it as an acceptable alternative to GPS or Glonass for use by commercial vessels.

What has enabled Beidou to progress so far and so fast from a standing start is its distinctive constellation design. GPS, Glonass, and Galileo are all designed to operate with constellations of 24 satellites each. All their satellites are in circular Medium Earth Orbits (MEOs), flying about 12,400 miles above the surface of the Earth, and taking about half a day to complete each orbit. And their orbits are all tilted, relative to the Equator, so as to form cage-like patterns. 

Beidou uses a mixture of satellite types, in different kinds of orbit. Five of the Beidou satellites are geostationary earth orbits (GEOs), orbiting nearly 19,500 nautical miles above the Equator. That means they take 24 hours to complete each orbit. If you could see them from the Earth’s surface, they would appear to be hovering over fixed points on the Equator, just like TV satellites do.

Galileo FOC satellite
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Another five are in Inclined Geosynchronous Orbits. They are at the same altitude as the GEO satellites, and also take 24 hours to complete each orbit, but their orbits are tilted. Instead of “hovering,” they drift north and south of the Equator, tracing out a figure-eight, returning to the same point at the same time every day.

And then there’s an inner constellation of MEOs similar to those used by GPS, Glonass, and Galileo. There are only four of them at the moment, but China has announced plans to add more, to build up to a GPS-like constellation of about 25 MEOs by 2017.

The advantage of this configuration is that it enables the Chinese to provide a high-accuracy, 24/7 positioning service with fewer satellites. It isn’t yet a worldwide service, but to a Beijing taxi driver or a Thai fisherman, the lack of Beidou coverage over the Atlantic is irrelevant. Millions of Beidou receivers have been built and sold so far, and are providing their users with 33-foot accuracy.

The signals transmitted by Beidou satellites are very similar to those of GPS and Glonass, so the international companies who make the chips that are at the heart of our chartplotters, car-satnav systems, and cell phones are already building Beidou capability into their products.

Whether the addition of Beidou will make a practical difference to U.S. boaters remains to be seen. In theory, it should help navigation systems lock on a bit more quickly, and that positions might be a bit more accurate, but it’s unlikely that either of these will be noticeable. Having more satellite systems available will make receivers a little less vulnerable to some types of jamming, and help to complicate spoofing. Most importantly, gathering data from multiple systems will keep our navigation systems running in the event of some sudden catastrophic failure of one entire system.

This article originally appeared in the March 2015 issue of Power & Motoryacht magazine.

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