The Man Who Created GPS

Roger Easton spearheaded the creation of the satellite system that lets us know where on Earth we are.

 

Roger Easton was a key figure in the development of the Global Positioning System, GPS, a ubiquitous feature of modern life.

What began as a way of tracking satellites like Sputnik became a way for satellites to track us here on the surface of Earth.

Easton's experiments with satellite tracking began in 1964, as the country tried to figure out what exactly was orbiting the Earth. Ten years later, he was granted a patent for "Navigation System Using Satellites and Passive Ranging Techniques." His system incorporated the main features of modern GPS, and because he was a scientist at the Naval Research Laboratory, the technology gave the United States a Cold War military advantage.

The Global Positioning System (GPS) is a space-based navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites.The system provides critical capabilities to military, civil, and commercial users around the world. The United States government created the system, maintains it, and makes it freely accessible to anyone with a GPS receiver.

Personal life 

Easton was born in Craftsbury, Vermont, and graduated from Middlebury College in 1943. He also attended the University of Michigan for 1 semester before joining the Naval Research Laboratory in 1943. At the Naval Research Laboratory he worked in the Radio Division on radar beacons and blind-landing systems. Easton also worked in the laboratory's Rocket-Sonde Branch which was dealing with space related research.Easton retired in 1980. In 1986, Easton ran for Governor and served 3 terms on the Board of the New Hampshire Electric Cooperative^.Easton died on May 8, 2014 at the age of 93.

Career

In 1955, Easton co-wrote the Naval Research Laboratory's Project Vanguard proposal for a U.S. satellite program in competition with two other proposals, including a proposal from the U.S. Army prepared by Wernher Von Braun. The Eisenhower Administration selected Project Vanguard. In 1957, Easton invented the Minitrack tracking system to determine the Vanguard satellite's orbit. When Sputnik I was launched, Easton extended the system to actively follow unknown orbiting satellites. 

In 1959, he designed the Naval Space Surveillance (NAVSPASUR) system. The Naval Space Surveillance System became the first system to detect and track all types of Earth-orbiting objects. It goes through the 33rd parallel, which is basically coast to coast. 

Later in his career at NRL, Easton conceived, patented, and led the development of essential enabling technologies for the United States Global Positioning System (GPS). During the 1960s and early 1970s he developed a time-based navigational system with passive ranging, circular orbits, and space-borne high precision clocks placed in satellites. The idea was tested with four experimental satellites: TIMATION I and II (in 1967 and 1969) and Navigation Technology Satellites (NTS) 1 and 2 (in 1974 and 1977). NTS-2 was the first satellite to transmit GPS signals.

Indian GPS satellite system   

Indian Regional Navigation Satellite System 

The Indian Regional Navigation Satellite System or IRNSS is an indigenously developed Navigation Satellite System that is used to provide accurate real-time positioning and timing services over India and region extending to 1500 km around India. The fully deployed IRNSS system consists of 3 satellites in GEO orbit and 4 satellites in GSO orbit, approximately 36,000 km altitude above earth surface.However, the full system comprises nine satellites, including two on the ground as stand-by.The requirement of such a navigation system is driven because access to foreign government-controlled global navigation satellite systems is not guaranteed in hostile situations, as happened to the Indian military depending on American GPS during the Kargil War.The IRNSS would provide two services, with the Standard Positioning Service open for civilian use, and the Restricted Service (an encrypted one) for authorized users (including the military).

  

Development

As part of the project, ISRO opened a new satellite navigation center within the campus of ISRO Deep Space Network (DSN) at Byalalu, in Karnataka on 28 May 2013. A network of 21 ranging stations located across the country will provide data for the orbital determination of the satellites and monitoring of the navigation signal.

A goal of complete Indian control has been stated, with the space segment, ground segment and user receivers all being built in India. Its location in low latitudes facilitates a coverage with low-inclination satellites. Three satellites will be in geostationary orbit over the Indian Ocean. Missile targeting could be an important military application for the constellation.

The total cost of the project is expected to be 1420 crore (US$209 million), with the cost of the ground segment being 300 crore (US$44 million). Each satellites costing 150 crore (US$22 million) and the PSLV-XL version rocket costs around 130 crore (US$19 million) . The seven rockets would involve an outlay of around 910 crore (US$134 million). The IRNSS signal has been released for evaluation in Sep 2014

 

Satellites

1. IRNSS-1A 
2. IRNSS-1B
3. IRNSS-1C
4. IRNSS-1D
5. IRNSS-1E
6. IRNSS-1F and IRNSS-1G