Does GPS Work Underwater?

Well, gee, no of course not, what a silly question to ask … or not.

Those who have read my writings for along time know that one of the primary reasons GPS ‘got off the ground’ literally was the support from the US Navy for a new system to replace the existing Transit satellite system which was built specifically to allow missile submarines (Boomers in the trade) to update their postions accurately … you cna’t control where a missile is going to land unless you know where you are firing it from.

But these vessels still need to surface (or come close enough to raise an antenna) in order to use GPS.  GPS on ships, though has revolutionized the face of maritime transportation.  Ships are no longer "somewhere between here and there"

One of the most interesting applications GPS has made much simpler and more precise is the laying down, maintenance and emergency repair of undersea cable systems.

Somehow a lot of people seem tothink that most of the world’s data gets from place to place via satellite … but this just isn’t so.

Satellites have some very important uses and in some locations of the world are heavily depended upon, but when you live in one populated country and click on a URL to visit a web page of interests the chances that your request and the information that comes back travels via undersea cable are high.

We, of course, were re-awakened to this fact just this morning when a couple of cables under the Mediterranean Sea apparently suffered some sort of damage and whole areas of the Middle East and India started receiving nothing but error messages.  here’s a map and write-up from a fascinating company that tracks these undersea cable systems … I think the average person would be absolutely amazed at how many systems there are already in place and how many are being built.  the world’s appetitive for digital information seems insatiable and underseas fiber optics is the only way to keep it in check.

So what’s GPS got to do with this?  In the simplest way we can be sure that one or more cable repair ships like this one (a ship I’ve personally spent time on as KDD maintained cables for me in Japan, … domo arigato, guys … are already steaming to the suspected break locations, of course navigating there via the shortest possible route using GPS.

Once over the site of the damage, they will use extremely precise survey-grade GPS systems to locate their positron within centimeters, fish up the cable, repair and restore to full operation.  It’s a fascinating process, and although it can be done without GPS … it was for more than 100 years … it works better. faster, cheaper today and brings us a lot of data we take for granted.

So, no, GPS signals can’t effectively be used underwater, but GPS has certainly reshaped the face of underwater work.