Bartosz Ciechanowski writes long, detailed explanatory articles about physics, math and engineering that are full of interactive, animated diagrams. His article on GPS, posted last January, digs down into all its fundamentals, from the principles of trilateration to the orbital mechanics of GPS satellites to exactly what a GPS signal consists of. “It’s fascinating how much complexity and ingenuity is hidden behind the simple act of observing one’s location in a mapping app on a smartphone. What I find particularly remarkable is how many different technological advancements were needed for GPS to work.”
More on the astonishing idea that Earth-orbiting GNSS satellites can be used for navigation at the Moon. The European Space Agency reports that among the instruments carried by the upcoming Lunar Pathfinder commercial mission will be a 1.4 kg satnav receiver that will test its ability to receive GPS and Galileo signals from lunar orbit. “Satnav position fixes from the receiver will be compared with conventional radio ranging carried out using Lunar Pathfinder’s X-band transmitter as well as laser ranging performed using a retroreflector contributed by NASA and developed by the KBR company.” Lunar Pathfinder is currently scheduled to launch in 2024.
GPS signals are relied upon by critical parts of our infrastructure, from transportation to communications to agriculture to financial markets. But those signals are easily spoofed or jammed and, at least in the United States, have no real backup (despite legislation mandating one by last year). Kate Murphy’s opinion piece in the New York Times not only serves as a summary of the problem, and a warning, it also does so in the most mainstream of newspapers: most of what I’ve read on the subject has been in the business, tech and science media. More people will see this. [MAPS-L]
Previously: GPS Is Easy to Disrupt, and the Consequences of Disruption Are Serious; A GPS Spoofing Mystery in Shanghai; The Economic Impact of GPS—and GPS Outages; The Russians Are Spoofing! The Russians Are Spoofing!
[I]t looks like things are slowly but surely coming back to life. Yesterday, activity-tracking app Strava confirmed that it was again able to send workout data to Garmin’s Connect service. […] But a quick look at Garmin’s system status page shows there are still plenty of issues across its platform.
Unfortunately, Garmin’s relative lack of communication around these issues means we still don’t know exactly what went wrong or when users can expect things to be back to normal. A few other key services, like registering a new device, are also back up and running, but if you’re still experiencing oddities with your Garmin devices, you’ll have to keep being patient.
Garmin’s FAQ on the outage is not particularly forthcoming.
Previously: Garmin’s Online Services Hit by Ransomware Attack.
Update, 1:48 PM: Garmin has issued a statement confirming that “it was the victim of a cyber attack that encrypted some of our systems on July 23, 2020.” There is no sign that customer data was affected, and they expect a return to normal within a few days. [Engadget]
Garmin’s online services have been hit by a ransomware attack, TechCrunch reports, with outages still ongoing as of this writing. “The incident began late Wednesday and continued through the weekend, causing disruption to the company’s online services for millions of users, including Garmin Connect, which syncs user activity and data to the cloud and other devices. The attack also took down flyGarmin, its aviation navigation and route-planning service.” Email and call centres are also reportedly out of operation.
Outside’s Andrew Skurka has posted a four-part series on the skills and tools required to navigate outdoors (remember outdoors?), which in general means knowing how not to get lost. In part one, “A Backpacker’s Guide to Maps,” Skurka recommends what kind of maps to take with you: paper maps, mainly, of various scales, but with digital maps as a backup. Part two, “The Gear You Need to Navigate in the Backcountry,” looks at equipment: not just GPS, but also basics like a compass, altimeter and a watch. In part three, “How to Master Navigational Storytelling,” is about developing a narrative of the route you’re taking to avoid getting lost. Finally, Skurka offers a checklist of skills to test yourself against.
Previously: The Lost Art of Finding Our Way.
More on the question of whether GPS can be used for navigation on the lunar surface—that is to say the existing constellations of Earth-orbiting GNSS satellites, not a new constellation of satellites around the moon. A new study suggests that the answer is yes: GPS and other navigation systems could be used.
Cheung and Lee plotted the orbits of navigation satellites from the United States’s Global Positioning System and two of its counterparts, Europe’s Galileo and Russia’s GLONASS system—81 satellites in all. Most of them have directional antennas transmitting toward Earth’s surface, but their signals also radiate into space. Those signals, say the researchers, are strong enough to be read by spacecraft with fairly compact receivers near the moon. Cheung, Lee and their team calculated that a spacecraft in lunar orbit would be able to “see” between five and 13 satellites’ signals at any given time—enough to accurately determine its position in space to within 200 to 300 meters. In computer simulations, they were able to implement various methods for improving the accuracy substantially from there.
A mini-network of relays—a couple of satellites in lunar orbit, say—could improve accuracy further. [Geography Realm]
Previously: Many Moon Maps.
GoPro’s Karma drone, released in October 2016 and discontinued in January 2018 (when GoPro announced it was getting out of the drone business), has apparently fallen prey to the GPS rollover bug: they’ve been grounded since the new year. See coverage at DP Review, Engadget and The Verge, as well as discussions at GoPro’s support website.
GoPro says they’re “actively troubleshooting” the issue; I have to say I’m surprised that a relatively new gadget—between two to three years old—could be hit by a once-every-19.7-year bug.
Previously: Happy GPS Week Rollover!
China’s Beidou satellite navigation system—a competitor to GPS like Russia’s GLONASS and Europe’s Galileo—will be complete by June 2020, when the constellation’s final two satellites are launched, the Associated Press reports. Twenty-four satellites have already been orbited. Whereas the first two iterations of Beidou offered regional coverage, this third iteration will cover the globe when complete. [Engadget, TechCrunch]
In an article in the December 2019 issue of Scientific American, now available online, Paul Tullis looks at the problem of GPS hacking, or spoofing—how easy it is to do, how vulnerable GPS is to it, and the consequences we’d face if GPS was disrupted on a broad level. It’s essential but scary reading. The potential scenarios Tullis describes are far more serious than the instances of GPS spoofing we’ve seen so far. It’s not just about navigation: a lot of critical infrastructure relies on GPS timestamps.
Tullis points out that other GNSS systems have terrestrial-based backup systems; GPS does not, despite a 15-year-old directive to build an eLORAN backup that would put out a signal too strong to spoof.
Someone is spoofing GPS signals in Shanghai, and we’re not entirely sure why they’re doing it, or how. One ostensibly bizarre theory: sand thieves trying to obfuscate illegal dredging by zonking out the GPS received by other ships’ AIS transponders. But how they’re redesignating ship (and bicycle) GPS locations into riverside circles, rather than, say, shifting everyone’s position a few kilometres away, has not yet been figured out. [MetaFilter]
Wirecutter’s Medea Giordano argues that even in the age of smartphones with built-in map apps, there’s still a place in your car for a dedicated GPS device: “there are cases when a phone just doesn’t cut it—say, in rural areas where coverage is questionable, or if you simply don’t want to drain your phone’s battery and data plan. Or when you’ve just found it frustrating to use a phone for long trips, like I have.”
With the 50th anniversary of Apollo 11 almost upon us, there’s been an uptick in moon-related content, which includes moon-related map content. For example:
New Exhibition. Opening today at The Map House in London, The Mapping of the Moon: 1669-1969, an exhibition of three centuries of lunar cartography. “The exhibition includes rare early 17th and 18th Century observations of the moon from astronomers such as Athanasius Kircher and Jean-Dominique Cassini, important maps produced by NASA for lunar exploration, globes and signed material by astronauts Neil Armstrong, Buzz Aldrin, Alan Bean and Jim Lovell.” Runs until 21 July. [ARTFIXDaily]
New Map. The July 2019 issue of National Geographic has a new map of the Moon that updates the 1969 painted version (see above) with a mosaic based on Lunar Reconnaissance Orbiter imagery. I don’t know whether that means a physical version of the map will be included with the issue as an insert, but I hope it does.
New Way to Navigate. NASA has a post on using GPS on the Moon. Now, I’d thought that using GPS on another world would require the deployment of a GPS satellite constellation around said world. No, this is about using Earth-orbiting GPS signals for lunar navigation, which simulations suggest is possible. The mind boggles.
A new study quantifies the economic benefits of GPS: in the U.S. alone, it estimates around $1.4 trillion in economic activity resulting from private-sector GPS use, about half of that coming from improvements in the telecommunications sector. (Roughly a quarter came from the telematics sector, and 15 percent from location-based services.) About 90 percent of those benefits have been generated in the last decade. The study also quantified the impact of a GPS outage: about a billion dollars a day, more if it occurred during planting season (agriculture has become reliant on GPS). [Ars Technica]
And speaking of GPS outages, earlier this month hundreds of flights were grounded over what appeared at first to be a GPS signal problem, but turned out to be a technical issue with GPS receivers made by Collins Aerospace. About 400 flights were cancelled on Sunday, 9 June, mostly involving Bombardier regional jets, but also other airliners and private aircraft. The FAA instructed pilots of affected aircraft to use other navigation methods; Collins says it has identified the issue and is working with the airlines. Coverage: AINonline, FlightGlobal, Forbes, GPS World, RNTF. [Jason Rabinowitz]
M. R. O’Connor’s book Wayfinding: The Science and Mystery of How Humans Navigate the World came out in April from St. Martin’s Press. Not coincidentally, she’s published a couple of pieces on the subject of that book, both of which focus on humans’ ability to pay attention to their surroundings, and the effect that relying on GPS directions might have on that ability. In a piece for Undark, O’Connor argues that “our unshakeable trust in GPS,” which traces itself back through hundreds of years of believing in the infallibility of maps, gets us lost because we’re relying on the device rather than our senses. Her piece for the Washington Post focuses on the role of the hippocampus in navigation and spatial awareness, and the need to exercise that part of the brain.