A watch to get you back home
by Cliff Smith
Within 10 years, hikers may be able to buy a $10 wrist device that will absolutely guarantee they will never get lost.
Ivan Getting, president of the Aerospace Corp., describes how the system will work and says the electronics for the position finder exist today. The last barrier to putting them into operating position will be cleared when the Space Shuttle flies in 1978, Getting said.
He said two satellites in stationary orbit 22,500 miles above the equator could serve most of the civilian navigation needs of the United States.
Initially, Getting suggested, both of the satellites will have cross-shaped transmission antennas 300 feet long and two feet wide.
One of the satellites would make a fan-shaped beam 10 miles wide at the earth’s surface reaching from Canada to Mexico. The other satellite would make the same-shaped beam reaching from coast to coast.
Both beams would sweep back and forth from border to border and from coast to coast every 10 seconds.
Then, if you are wearing your navigational wrist radio, you could determine your position in any direction within one-half mile, Getting said.
He said the shuttle also will have a payload to permit the deployment of transmission antennas considerably larger.
If the cross-shaped antennas were made two miles long, rather than 311 feet, be said, you could tell your position in the densest forest or on a foggy sea to within 100 feet.
“There is no technical reason whatsoever why we all couldn’t have these wristwatches (the radios would also tell time to within a billionth of a second) within 10 years,” Getting said. “They would cost only about $10.”
For the military, something even better is coming sooner. Late next year, the first of 24 satellites making up what is called the Global Positioning Satellite (GPS) system will ride into earth orbit on Atlas missiles.
The GPS satellites will turn about the earth in several planes, broadcasting time and exact position data in a top secret code receivable only by US military units.
Getting said the reference data will be good enough for a ship or airplane to be able to quickly plot its position anywhere on the globe with a three-dimensional accuracy of one foot in any kind of weather. This represents a 20-fold accuracy improvement over the best military electronic navigational system available today, Getting said, and the existing system is two-dimensional and has weaknesses when used on fast-moving targets.
Image: GPS 1-2 (Navstar 2), launched 5/13/78. Also known as Navigational Development Satellite 2; 1st generation Global Positioning System.