29 Facts About GPS

1.

Global Positioning System, originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force.

FactSnippet No. 1,201,811
2.

GPS project was started by the U S Department of Defense in 1973.

FactSnippet No. 1,201,812
3.

Advances in technology and new demands on the existing system have now led to efforts to modernize the GPS and implement the next generation of GPS Block IIIA satellites and Next Generation Operational Control System .

FactSnippet No. 1,201,813
4.

Russian Global Navigation Satellite System was developed contemporaneously with GPS, but suffered from incomplete coverage of the globe until the mid-2000s.

FactSnippet No. 1,201,814
5.

GPS project was launched in the United States in 1973 to overcome the limitations of previous navigation systems, combining ideas from several predecessors, including classified engineering design studies from the 1960s.

FactSnippet No. 1,201,815

Related searches

United States Space LORAN UTC Time
6.

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.

FactSnippet No. 1,201,816
7.

The design of GPS corrects for this difference; because without doing so, GPS calculated positions would accumulate errors of up to 10 kilometers per day .

FactSnippet No. 1,201,817
8.

GPS's was concerned with the curving of the paths of radio waves traversing the ionosphere from NavSTAR satellites.

FactSnippet No. 1,201,818
9.

Since its deployment, the U S has implemented several improvements to the GPS service, including new signals for civil use and increased accuracy and integrity for all users, all the while maintaining compatibility with existing GPS equipment.

FactSnippet No. 1,201,819
10.

GPS is owned and operated by the United States government as a national resource.

FactSnippet No. 1,201,820
11.

In 1998, GPS technology was inducted into the Space Foundation Space Technology Hall of Fame.

FactSnippet No. 1,201,821
12.

GPS receiver calculates its own four-dimensional position in spacetime based on data received from multiple GPS satellites.

FactSnippet No. 1,201,822
13.

GPS receivers have clocks as well, but they are less stable and less precise.

FactSnippet No. 1,201,823
14.

In practice the receiver position and the offset of the receiver clock relative to the GPS time are computed simultaneously, using the navigation equations to process the TOFs.

FactSnippet No. 1,201,824
15.

GPS requires four or more satellites to be visible for accurate navigation.

FactSnippet No. 1,201,825
16.

User segment is composed of hundreds of thousands of U S and allied military users of the secure GPS Precise Positioning Service, and tens of millions of civil, commercial and scientific users of the Standard Positioning Service.

FactSnippet No. 1,201,826
17.

In general, GPS receivers are composed of an antenna, tuned to the frequencies transmitted by the satellites, receiver-processors, and a highly stable clock .

FactSnippet No. 1,201,827
18.

GPS has become a widely deployed and useful tool for commerce, scientific uses, tracking, and surveillance.

FactSnippet No. 1,201,828
19.

The war demonstrated the vulnerability of GPS to being jammed, when Iraqi forces installed jamming devices on likely targets that emitted radio noise, disrupting reception of the weak GPS signal.

FactSnippet No. 1,201,829
20.

GPS's vulnerability to jamming is a threat that continues to grow as jamming equipment and experience grows.

FactSnippet No. 1,201,830
21.

GPS signals have been reported to have been jammed many times over the years for military purposes.

FactSnippet No. 1,201,831
22.

The difference is that GPS time is not corrected to match the rotation of the Earth, so it does not contain leap seconds or other corrections that are periodically added to UTC.

FactSnippet No. 1,201,832
23.

GPS time was set to match UTC in 1980, but has since diverged.

FactSnippet No. 1,201,833
24.

The lack of corrections means that GPS time remains at a constant offset with International Atomic Time .

FactSnippet No. 1,201,834
25.

GPS time is theoretically accurate to about 14 nanoseconds, due to the clock drift relative to International Atomic Time that the atomic clocks in GPS transmitters experience Most receivers lose some accuracy in their interpretation of the signals and are only accurate to about 100 nanoseconds.

FactSnippet No. 1,201,835

Related searches

United States Space LORAN UTC Time
26.

Navigational signals transmitted by GPS satellites encode a variety of information including satellite positions, the state of the internal clocks, and the health of the network.

FactSnippet No. 1,201,836
27.

The GPS community had not objected to the LightSquared applications until November 2010, when LightSquared applied for a modification to its Ancillary Terrestrial Component authorization.

FactSnippet No. 1,201,837
28.

GPS was initially developed assuming use of a numerical least-squares solution method—i.

FactSnippet No. 1,201,838
29.

GPS makes corrections for receiver clock errors and other effects, but some residual errors remain uncorrected.

FactSnippet No. 1,201,839