Concerned about the vulnerability of GPS to disruption from a myriad of sources, the US Naval Academy, US Coast Guard Academy, US Merchant Marine Academy and others have reinstated instruction in celestial navigation.
This requires measuring the height of the sun, moon and stars above the horizon, and knowing the exact time.
Problem is, most ships don’t go to the expense and trouble of maintaining chronometers any more. They were disposed of long ago after much more precise time became available from GPS.
So maritime students, and most mariners, get the exact time for their GPS-free celestial navigation from GPS.
Here is an article by Doug Taggart from the recent Institute of Navigation newsletter about how he discovered this while sailing aboard the Coast Guard’s square rigged training ship CGC EAGLE last summer. – We have been reliably informed that the same thing also happens on Navy and merchant ships.
But this is much more than a maritime problem.
GPS is an invisible utility. Few people realize how deeply embedded it is in virtually every technology.
Here is a link to the entire Institute of Navigation quaterly newsletter. If you aren’t a member of ION, consider joining today!
Photo of US Navy midshipman practicing celestial navigation by PH2 Micheal D. P. Flynn