GPS

A world changing invention!

by Dominique Richard

Dominique Richard, geologist and PhD candidate at Polytechnique School of Montreal.

Dominique Richard, geologist and PhD candidate at Polytechnique School of Montreal.

We are a family of four, an as we get in the car and start to drive off to go somewhere, here is what you can typically hear: 

— So did you bring the diapers, the change of clothes, the P.J.’s?
 — yep
— Toothbrushes? the wine? (nod)
(from the back) — Can I have a snack?
— Here you go. You brought the gift?
— unhum
— Mommy, can you put on my music?

Skip skip skip to my lou, skip to my lou my darling…

—Okay so we're good!  So … can you hand me your phone and I’ll try to figure out where we are going exactly.

Thanks to the GPS in our smartphone, we can now get directions to where we are going on the move. This is just one example of how GPS affects our daily lives. But where does this technology come from? We vaguely know it came from the U.S. army, at some point, but here are a few more facts about the story of this great invention.

The idea behind the global positioning system (GPS) was inspired by the Soviet satellite Sputnik in 1957. Scientists from MIT realized the Doppler Effect from Sputnik’s radio signal could be used to track the satellite from the ground. They imagined that by measuring the frequency of radio signals, the location of receivers on the ground could also be tracked by using distances from different satellites. In 1959, the U.S. Navy built TRANSIT, the first real satellite navigation system. Submarines often had to wait hours to receive signals from these satellites, but this first step set the stage for the development of continuous signaling systems. The GPS as we know it today was invented and designed between the 1960’s and early 1970’s by Roger Lee Easton (Naval Research Laboratory), Ivan Alexander Getting (Aerospace Corporation) and Bradford Parkinson (US Air Force). Between 1974-1985 and 1989-1993, the U.S. military launched twenty-four NAVSTAR satellites, which became known as "the GPS ". This system of 24 satellites was fully operational in 1995.  

Exclusively military in the beginning, the GPS was open to civil use in the late 1980’s. The incentive for this change was given to the U.S. Administration when the USSR shot down passenger jet-flight 007 from Korean Airlines in 1983 for trespassing on their territory. After this tragedy, President Reagan offered to open GPS to civilian commercial aircrafts so they could know their position and avoid restricted foreign territories.

Because the U.S. military feared the GPS would be used by their adversaries, they deliberately decreased the accuracy of the civilian signal from 1990 to 2000. In 2000, when the GPS signal all of a sudden became ten times more accurate many industries (mineral exploration, forestry, etc.) started using this technology. In June 2011 the GPS was expanded from a 24-slot constellation to a 27-slot constellation for an improved coverage. Today, there are 31 operational satellites in the GPS constellation; 4 of which are considered spares.

Other satellite systems exist or are under development. GLONASS from Russia was operational for a few years at the end the 90’s and has been restored in 2010. Galileo from the European Union should be fully operational in 2020. Other country’s such as India, China and Japan are also developing similar systems.

As a geologist, I think it’s fair to say GPS completely revolutionized my field of work.  I started using the GPS about ten years ago during a field class trip. There weren’t enough handheld GPS devices for all the students so we did part of the mapping by counting our paces, the old way (I doubt students even try pace counting today). In recent years, I worked with very large geo-referenced datasets, comparing many layers of information at the click of a button. The work of a geologist now seems so far from the prehistoric times of hand drawn maps and pace counting of the 1980’s and 1990’s.