Global Positioning System

GPSGlobal Positioning System (GPS)global positioning systemsglobal positioningGPS receiversGPS receiverGPS systemglobal positioning satelliteGlobal Positioning Systems (GPS)GPS equipment
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Air Force.wikipedia
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GLONASS

Global Navigation Satellite SystemGLONASS GPSGLONASS K
The Russian Global Navigation Satellite System (GLONASS) was developed contemporaneously with GPS, but suffered from incomplete coverage of the globe until the mid-2000s.
It provides an alternative to GPS and is the second navigational system in operation with global coverage and of comparable precision.

Satellite navigation

navigation satelliteNavigationglobal navigation satellite system
It is a global navigation satellite system that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites.
A satellite navigation system with global coverage may be termed a global navigation satellite system (GNSS)., the United States' Global Positioning System (GPS) and Russia's GLONASS are fully operational GNSSs, with China's BeiDou Navigation Satellite System (BDS) and the European Union's Galileo scheduled to be fully operational by 2020.

Bradford Parkinson

Bradford W. Parkinson[5
Roger L. Easton of the Naval Research Laboratory, Ivan A. Getting of The Aerospace Corporation, and Bradford Parkinson of the Applied Physics Laboratory are credited with inventing it. Gladys West is credited with pioneering the mathematical and computational techniques for detecting satellite positions with the precision needed for GPS.
He is best known as the lead architect, advocate and developer, with early contributions from Ivan Getting and Roger Easton, of the Air Force NAVSTAR program, better known as Global Positioning System.

Galileo (satellite navigation)

GalileoGalileo positioning systemGalileo project
There are also the European Union Galileo positioning system, and India's NAVIC.
One of the aims of Galileo is to provide an independent high-precision positioning system so European nations do not have to rely on the U.S. GPS, or the Russian GLONASS systems, which could be disabled or degraded by their operators at any time.

Roger L. Easton

Roger EastonRoger Easton, Sr.
Roger L. Easton of the Naval Research Laboratory, Ivan A. Getting of The Aerospace Corporation, and Bradford Parkinson of the Applied Physics Laboratory are credited with inventing it. Gladys West is credited with pioneering the mathematical and computational techniques for detecting satellite positions with the precision needed for GPS.
Roger Lee Easton, Sr. (April 30, 1921 – May 8, 2014) was an American scientist/physicist who was the principal inventor and designer of the Global Positioning System, along with Ivan A. Getting and Bradford Parkinson.

Gladys West

Roger L. Easton of the Naval Research Laboratory, Ivan A. Getting of The Aerospace Corporation, and Bradford Parkinson of the Applied Physics Laboratory are credited with inventing it. Gladys West is credited with pioneering the mathematical and computational techniques for detecting satellite positions with the precision needed for GPS.
Gladys Mae West (née Brown) (born 1930 or 1931) is an American mathematician known for her contributions to the mathematics underpinning the Global Positioning System.

Force multiplication

force multiplierforce multipliersforce-multiplier
Considered vital to the nuclear deterrence posture, accurate determination of the SLBM launch position was a force multiplier.
For example, if a certain technology like GPS enables a force to accomplish the same results of a force five times as large but without GPS, then the multiplier is five.

United States Naval Research Laboratory

Naval Research LaboratoryNRLU.S. Naval Research Laboratory
Roger L. Easton of the Naval Research Laboratory, Ivan A. Getting of The Aerospace Corporation, and Bradford Parkinson of the Applied Physics Laboratory are credited with inventing it. Gladys West is credited with pioneering the mathematical and computational techniques for detecting satellite positions with the precision needed for GPS.
The Global Positioning System (GPS) was invented at NRL and tested by NRL's Timation series of satellites.

DARPA

ARPADefense Advanced Research Projects AgencyAdvanced Research Projects Agency
In 1959, ARPA (renamed DARPA in 1972) also played a role in TRANSIT.
ARPA at this point (1959) played an early role in Transit (also called NavSat) a predecessor to the Global Positioning System (GPS).

Satellite constellation

constellationsatellite constellationsconstellations
It used a constellation of five satellites and could provide a navigational fix approximately once per hour.
Examples of satellite constellations include the Global Positioning System (GPS), Galileo and GLONASS constellations for navigation and geodesy, the Iridium and Globalstar satellite telephony services, the Disaster Monitoring Constellation and RapidEye for remote sensing, the Orbcomm messaging service, Russian elliptic orbit Molniya and Tundra constellations, the large-scale Teledesic and Skybridge broadband constellation proposals of the 1990s, and more recent systems such as O3b or the OneWeb proposal.

Geolocation

geo-locationgeolocategeolocated
It is a global navigation satellite system that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites.
When satellite navigation (such as GPS) signals are unavailable, geolocation applications can use information from cell towers to triangulate the approximate position, a method that is not as accurate as GPS but has greatly improved in recent years.

Decca Navigator System

DeccaDecca transmitterDECCA (hyperbolic) navigation
The design of GPS is based partly on similar ground-based radio-navigation systems, such as LORAN and the Decca Navigator, developed in the early 1940s.
Decca was eventually replaced, along with Loran and similar systems, by the GPS during the 1990s.

Differential GPS

DGPSDifferential Global Positioning Systemposition information
The directive was proposed by the U.S. Secretary of Defense, William Perry, in view of the widespread growth of differential GPS services to improve civilian accuracy and eliminate the U.S. military advantage.
Differential Global Positioning Systems (DGPS) are enhancements to the Global Positioning System (GPS) which provide improved location accuracy, in the range of operations of each system, from the 15-meter nominal GPS accuracy to about 10 cm in case of the best implementations.

GPS Block IIF

Block IIFGPS IIFGPS IIF SV-1
GPS Block IIF, or GPS IIF is an interim class of GPS (satellite), which are used to keep the Navstar Global Positioning System operational until the GPS Block IIIA satellites become operational.

Timation

In 1967, the U.S. Navy developed the Timation satellite, which proved the feasibility of placing accurate clocks in space, a technology required for GPS.
The results of this program and Air Force Project 621B formed the basis for the Global Positioning System (GPS).

50th Space Wing

50th Tactical Fighter Wing50th Fighter-Bomber Wing50th Fighter Wing
In 1992, the 2nd Space Wing, which originally managed the system, was inactivated and replaced by the 50th Space Wing.
The 50th Space Wing also manages the Global Positioning System.

Assisted GPS

A-GPSaGPSAssisted
November 2004, Qualcomm announced successful tests of assisted GPS for mobile phones.
Assisted GPS or Augmented GPS (abbreviated generally as A-GPS and less commonly as aGPS) is a system that often significantly improves the startup performance—i.e., time-to-first-fix (TTFF)—of a GPS satellite-based positioning system.

GPS satellite blocks

Block IIRBlock IIABlock I
Ten "Block I" prototype satellites were launched between 1978 and 1985 (an additional unit was destroyed in a launch failure).
A GPS satellite is a satellite used by the NAVSTAR Global Positioning System (GPS).

Korean Air Lines Flight 007

KAL 007Flight 007Korean Air Flight 007
After Korean Air Lines Flight 007, a Boeing 747 carrying 269 people, was shot down in 1983 after straying into the USSR's prohibited airspace, in the vicinity of Sakhalin and Moneron Islands, President Ronald Reagan issued a directive making GPS freely available for civilian use, once it was sufficiently developed, as a common good.
In addition, the incident was one of the most important events that prompted the Reagan administration to allow worldwide access to the United States Global Positioning System (GPS).

UGM-27 Polaris

PolarisPolaris missilePolaris A-3
(At the time, the Navy was developing the submarine-launched Polaris missile, which required them to know the submarine's location.) This led them and APL to develop the TRANSIT system.
A predecessor to the GPS satellite navigation system, the Transit system (later called NAVSAT), was developed because the submarines needed to know their position at launch in order for the missiles to hit their targets.

Time transfer

time referencecommon-view GPStime information
It is a global navigation satellite system that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites.
Examples of a one-way time transfer system are the clock on a church or town building and the ringing of their time-indication bells; time balls, radio clock signals such as LORAN, DCF77 and MSF; and finally the Global Positioning System which uses multiple one-way time transfers from different satellites, with positional information and other advanced means of delay compensations to allow receiver compensation of time and position information in real time.

Transit (satellite)

TransitAN/UYK-1TRANSIT system
(At the time, the Navy was developing the submarine-launched Polaris missile, which required them to know the submarine's location.) This led them and APL to develop the TRANSIT system.
The Transit system was made obsolete by the Global Positioning System (GPS), and ceased navigation service in 1996.

Ivan A. Getting

Ivan GettingDr. Ivan Alexander GettingGetting, Ivan
Roger L. Easton of the Naval Research Laboratory, Ivan A. Getting of The Aerospace Corporation, and Bradford Parkinson of the Applied Physics Laboratory are credited with inventing it. Gladys West is credited with pioneering the mathematical and computational techniques for detecting satellite positions with the precision needed for GPS.
Ivan Alexander Getting (January 18, 1912 – October 11, 2003) was an American physicist and electrical engineer, credited (along with Roger L. Easton and Bradford Parkinson) with the development of the Global Positioning System (GPS).

Atomic clock

atomic clocksatomiccaesium clock
The satellites carry very stable atomic clocks that are synchronized with one another and with the ground clocks.
Atomic clocks are the most accurate time and frequency standards known, and are used as primary standards for international time distribution services, to control the wave frequency of television broadcasts, and in global navigation satellite systems such as GPS.

Radionavigation-satellite service

Radio Navigation Satellite Servicesradionavigationsatellite-based navigation
The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Air Force.
Global Positioning System (GPS), with Differential GPS (DGPS)