What is a GPS? How does it work?

The Global Positioning System (GPS) tells you where you are on Earth. 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 1960's 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.

In the early 1970's, the Department of Defense (DoD) wanted to ensure a robust, stable satellite navigation system would be available. Embracing previous ideas from Navy scientists, the DoD decided to use satellites to support their proposed navigation system. DoD then followed through and launched its first Navigation System with Timing and Ranging (NAVSTAR) satellite in 1978. The 24 satellite system became fully operational in 1993.

Today, GPS is a multi-use, space-based radionavigation system owned by the US Government and operated by the United States Air Force to meet national defense, homeland security, civil, commercial, and scientific needs. GPS currently provides two levels of service: Standard Positioning Service (SPS) which uses the coarse acquisition (C/A) code on the L1 frequency, and Precise Positioning Service (PPS) which uses the P(Y) code on both the L1 and L2 frequencies. Access to the PPS is restricted to US Armed Forces, US Federal agencies, and selected allied armed forces and governments. The SPS is available to all users on a continuous, worldwide basis, free of any direct user charges. The specific capabilities provided by SPS are published in the Global Positioning System Performance Standards and Specifications.

Who invented the GPS? People behind the Global Positioning System.

That Alexander Graham Bell did not invent the telephone could be proven in court 113 years after the original inventor Antonio Meucci died. Thomas Edison’s name comes to mind when someone says ‘light bulb,’ but it was Humphry Davy who showed for the first time how light can be cast by passing an electric current through a platinum strip. The history of science is riddled with inventions whose ownership is hotly disputed. The Global Positioning System (GPS) is one of them. Who invented the GPS then?

GPS has become such an indispensable part of modern life that we have almost become dependent on it. It has slowly and steadily crept into our cars, ships, airplanes, cameras, construction equipment, agricultural machinery, laptops, and of course, smartphones.

And yet, there is a lack of consensus over who should be credited with its creation. At least four different people have been acknowledged to be clearly associated with the invention of this revolutionary technology which was ultimately developed by the US Department of Defense to assist the military forces.

Roger L. Easton

This former head of Naval Research Laboratory’s space applications branch was the brain behind several engineering applications and technologies that enabled the development of the GPS. A Cold War scientist, Easton worked on technology to track satellites like the Soviet Union’s Sputnik before fathering a time-based navigational concept called TIMATION which utilized passive ranging, circular orbits, and space-borne high precision clocks synchronized to a master clock. Even today, these features are vital in any modern GPS.

In 2004, Easton received the United States National Medal of Technology and Innovation from then-President George W. Bush. The honor was bestowed in recognition of “extensive pioneering achievements in spacecraft tracking, navigation, and timing technology that led to the development of the NAVSTAR-Global Positioning System.”

However, it wasn’t until 2010 that National Inventors Hall of Fame recognized Easton’s efforts in the creation of the GPS. In fact, in 2004, two other people were inducted into the Hall of Fame for championing the development of GPS technology.

Dr. Ivan Getting

The Inventors Hall of Fame credits Dr. Getting for pressing forward “the concept of using an advanced system of satellites to allow the calculation of exquisitely precise positioning data for rapidly moving vehicles, ranging from cars to missiles.”

This founding president of The Aerospace Corporation is also recognized by the American National Academy of Engineering who awarded him the Charles Stark Draper Prize for Engineering in 2003 for the “concept and development of the GPS”. More specifically, the Academy credits Dr. Getting for his work on “the design of GPS, on its operational value, and on planning, negotiation, and reaching agreements with all the system’s stakeholders was critical to its becoming a reality.

Dr. Getting proposed a three-dimensional, time-difference-of-arrival position-finding system for navigation and by his own admission, “one of the proposals put forth by The Aerospace Corporation… was essentially what is now the GPS.” While acknowledging that the Navy had already developed a very good space navigation system when this proposal was put forward to the Department of Defense, Dr. Getting says, “The conclusion of the Director of Defense Research & Engineering (DDRE) was that a single system was required and that it should be based on the Air Force/Aerospace concept called GPS and developed by the Air Force with cooperation from all three services.”
Bradford Parkinson

Brad Parkinson

Parkinson was at the forefront of the NAVSTAR GPS Joint Program Office from 1972 to 1978. The Inventors Hall of Fame is clear that “as the program’s first manager, he has been the chief architect of GPS throughout the system’s conception, engineering development, and implementation.” This has also earned Parkinson the title the ‘Father of GPS’.

Parkinson, an Air Force colonel at the time, was tasked to revive a Space and Missile Systems Organization program called 621B that provided altitude, as well as latitude and longitude for navigation purposes. And once the Department of Defense decided that it wanted a joint program developed with the cooperation of all military services, Parkinson was put in charge to pull such a program together.

Parkinson says in a Stanford address that this new program pulled the clocks from Easton’s TIMATION, the signal structure of 621B, and the orbital prediction method from another Navy navigation system called TRANSIT which was developed at the Johns Hopkins University Applied Physics Laboratory. Together, these formed the NAVSTAR-Global Positioning System.

A Timeline of GPS History

whenwasgpsinvented
1978
The first experimental Block-I GPS satellite was launched in February 1978. The GPS satellites were initially manufactured by Rockwell International and are now manufactured by Lockheed Martin.

1983
In 1983, after Soviet interceptor aircraft shot down the civilian airliner KAL 007 in restricted Soviet airspace, killing all 269 people on board, U.S. President Ronald Reagan announced that the GPS system would be made available for civilian uses once it was completed.

1985
By 1985, ten more experimental Block-I satellites had been launched to validate the concept.

1989
On February 14, 1989, the first modern Block-II satellite was launched.

Old Satellite Orbiting Earth
1991
The oldest GPS satellite still in operation was launched in August 1991.

1992
The 2nd Space Wing, which originally managed the system, was de-activated and replaced by the 50th Space Wing in 1992.

1993-1994
By December 1993 the GPS system achieved initial operational capability and a complete constellation of 24 satellites was in orbit by January 17, 1994.

1996
In 1996, recognizing the importance of GPS to civilian users as well as military users, U.S. President Bill Clinton issued a policy directive declaring GPS to be a dual-use system and establishing an Interagency GPS Executive Board to manage it as a national asset.

1998
In 1998, U.S. Vice President Al Gore announced plans to upgrade GPS with two new civilian signals for enhanced user accuracy and reliability, particularly with respect to aviation safety.

2000
“Selective availability” was discontinued, allowing users outside the US military to receive a full quality signal on May 2, 2000.

2004
In 2004, U.S. President George W. Bush updated the national policy, replacing the executive board with the National Space-Based Positioning, Navigation, and Timing Executive Committee.

2006
The most recent launch was on 17 November 2006.

GPS Awards in History


Two GPS developers have received the National Academy of Engineering Charles Stark Draper Prize in 2003.

Ivan Getting, emeritus president of The Aerospace Corporation and engineer at the Massachusetts Institute of Technology, established the basis for GPS, making improvements on the World War II land-based radio system called LORAN (Long-range Radio Aid to Navigation).

Bradford Parkinson, professor of aeronautics and astronautics at Stanford University, conceived the present satellite-based system in the early 1960s and developed it in conjunction with the U.S. Air Force.

One GPS developer, Roger L. Easton, received the National Medal of Technology on February 13, 2006 at the White House.

On February 10, 1993, the National Aeronautic Association selected the Global Positioning System Team as winners of the 1992 Robert J. Collier Trophy, the most prestigious aviation award in the United States. This team consists of researchers from the Naval Research Laboratory, the U.S. Air Force, the Aerospace Corporation, Rockwell International Corporation, and IBM Federal Systems Company. The citation accompanying the presentation of the trophy honors the GPS Team “for the most significant development for safe and efficient navigation and surveillance of air and spacecraft since the introduction of radio navigation 50 years ago.”

Other Systems


GLONASS (GLObal NAvigation Satellite System) is operated by Russia, although with only twelve active satellites as of 2004. In Russia, Northern Europe and Canada, at least four GLONASS satellites are visible 45% of time. There are plans to restore GLONASS to full operation by 2008 with assistance from India.

Joined by China, Israel, India, Morocco, Saudi Arabia and South Korea, and Ukraine, the European Union developed plans for Galileo to be operational by 2010.





Purpose of the GPS System & Why it Was Started

Global positioning systems, once solely for military use, have taken off as personal commercial devices, helping people do everything from find driving directions to map the earth. The short history of GPS pales in comparison to the potential future applications of this vibrant technology.

How It Works

A global positioning system calculates the real-time position of a device using atomic clocks and orbital satellites. GPS satellites continuously broadcast signals that tell the satellite's location and time, accurate to a billionth of a second. A GPS unit in, say, an automobile uses the signals from up to four satellites to calculate its own relative position.

History

Global positioning systems were originally created for military use in the 1970s. However, the precursor is the Transit satellite navigation system, first used by the United States Navy in 1965. This system was originally developed to help submarines navigate. When the United States government found itself needing a foolproof satellite navigation system, the best minds in the Pentagon put their heads together and came up with the concept of GPS in 1973. The first GPS satellite was launched in 1978 and since then the technology has been broadened for commercial use.

Significance

The technology has staggering significance militarily. It helps friendly troops stay organized and find their way back to base or to targets. It can also help pinpoint enemy positions and threats. The military was initially wary of giving up the technology to the corporate sector. However, the Pentagon was persuaded by corporations who saw the vast potential market for the technology. Today, GPS is used by millions to navigate on a daily basis and can be immensely useful in mapping driving or walking directions.

gps satellites

Aside from using GPS in an automobile or on the street to find directions, it has a variety of other important uses. GPS is used for mapping and surveying the earth. It is also able to help monitor earthquakes. Civilian pilots use GPS in flight, as do airlines to coordinate flights. The technology is also used by companies to keep track of the very satellites that make GPS possible.


Future Uses

The future of GPS is looking bright. Programs like Google Earth are just the beginning of what can be done with global positioning technology. Militarily, more accurate and faster GPS systems can give troops and commanders up to date analysis of friendly and enemy troop movement. With GPS becoming smaller and more powerful, it can also be used for individual soldiers in the field to triangulate their position. Commercially, the technology has exploded in the past few years, allowing anyone and everyone to afford powerful GPS units in their automobiles and homes. That technology is now making the jump to mobile smart phones.

The primary incarnation of this approach began in 1974 when the U.S. Air Force started development of the first of a series of Navstar satellites, the ground control system, and various types of military user equipment.

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