A Brief History of (GPS) Global Positioning System
Here’s an article about a brief history of (GPS) Global Positioning System:
GPS has its origins in the Sputnik era when scientists were able to track the satellite with shifts in its radio signal known as the “Doppler Effect.” The United States Navy conducted satellite navigation experiments in the mid-1960s. This is to track US submarines carrying nuclear missiles. With six satellites orbiting the poles, submarines were able to observe the satellite changes in Doppler. And pinpoint the submarine’s location within a matter of minutes.
It started out as a global navigation system for military land-based and air vehicles. With some limited use for the civilian population. But today, the tables have turned – there are more GPS receivers used by civilians than by the military!
GPS has come a long way since Sputnik. Here are the major milestones along the way.
The Navy built the first real satellite navigation system, which it called TRANSIT. The system’s designed to locate submarines and started out with six satellites and eventually grew to ten. The subs often had to wait hours to receive signals from the satellites. But the model set the stage for true GPS with continuous signaling from satellites in space.
The Aerospace Corporation completed a study for the military that proposes a system of space satellites that send signals continuously to receivers on the ground and could locate vehicles moving rapidly across the earth’s surface or in the air. The study lays out the GPS concept that we know today for the first time: receivers in vehicles on the ground would derive a precise set of location coordinates by measuring the transmission times of radio signals from satellites.
After working on a GPS system for the past 11 years, the branches of the military launch the first satellite. Called as the NAVSTAR it is a proposed 24-satellite GPS system.
Also, in 1974
In 1974 they launched the first GPS satellite. And in 1994 they declared the GPS satellite that is fully operational. The satellites were/are designed and built by Rockwell International, Boeing, and Lockheed-Martin.
The military launches 11 more test satellites into space to test the NAVSTAR system. Which they now call “the GPS System”.
The government contracts with private companies to develop “airborne, shipboard. And man-pack (portable)” GPS receivers.
After years of testing, the Air Force finally launches the first fully operational GPS satellite into space.
Magellan Corporation claims to be the first to market in the U.S… With a hand-held navigation device, the Magellan NAV 1000.
Defense Department decides to deliberately decrease the accuracy of the system.
The first rev of the GPS system was finally completed. Launching a full “constellation” of 27 fully operational GPS satellites into space.
Mobile phone manufacturer Benefon launched the first commercially-available GPS phone.
GPS receiver technology got much smaller and cheaper. Private companies began pumping out personal GPS products. l
Launching the first of a new generation of GPS satellite, called “Block II,” from Cape Canaveral. The new breed of satellite transmitted signals on a second, dedicated civilian channel.
The Air Force launched two new GPS satellites, one in 2010 and one in 2011. They both meant to keep the constellation operable until the next generation “Block III” satellites can begin launching in 2014. The new Block III satellites will add a more civilian GPS signal. And will enhance the performance of existing GPS service.
At present, the Air Force manages a constellation of 31 operational GPS satellites, plus three decommissioned satellites that can be reactivated if needed. The constellation is being managed to ensure the availability of at least 24 GPS satellites, 95% of the time.