09-05-2012, 03:42 PM
Global Positioning System
GPS.pdf (Size: 1.73 MB / Downloads: 156)
Introduction
Have you ever been lost and wished there was an easy way you needed to go?
Ever find that perfect fishing or hunting spot and not been able to remember how to
get back to it easily?
How about finding yourself out hiking and not knowing which direction you should
go to get back to your camp or car?
Ever been flying along and needed to locate the nearest airspace you were in?
Maybe you've been faced with the fact that it's time to pull over and ask someone for
directions.
Global Positioning System technology is rapidly changing how people find their way
around the earth. Whether it is for fun, saving lives, getting there faster, or whatever
uses you can dream up, GPS navigation is becoming more common everyday.
Understanding the principle of GPS Technology Theory :
The Global Positioning System (GPS) is and earth orbiting-satellite based navigation
system. GPS is an operational system, providing users worldwide with twenty-four
hour a day precise position in three dimensions and precise time traceable to global
time standards. GPS is operated by the United States Air Force under the direction of
the Department of Defense (DoD) and was designed for, and remains under the
control of, the United States military. While there are now many thousands of
commercial and recreational civil user’s worldwide, DoD control still impacts many
aspects of GPS planning, operation, and use. Primarily designed as a land, marine,
and aviation navigation system, GPS applications have expanded to include
surveying, space navigation, automatic vehicle monitoring, emergency services
dispatching, mapping, and geographic information system georeferencing. Because
the dissemination of precise time is an integral part of GPS, a large community of
precise time, time interval, and frequency standard users has come to depend on GPS
as a primary source of control traceable through the United States Naval Observatory
to global time and frequency standards.
History of GPS :
Developed in the 1960s, the Navy Transit satellite navigation system still provides
some service as a two-dimensional (horizontal) positioning system. Good (200 meter)
Transit positioning requires knowledge of the user altitude as well as a model of user
dynamics during the fix, a process of integrating satellite signal Doppler shifts (the
change in received signal frequency caused by the changing range) during the fly-over
of the satellite. Another Navy system, based on the Timation satellites carried stable
clocks (quartz, rubidium, and cesium) over the course of the program in the 1960s and
70s and was the precursor to the precise time capabilities of GPS (Easton 1978). GPS
began in 1973 as a test program using ground-based transmitters at the U. S.
Civil andMilitary GPS :
While controlled and maintained by the DoD, the GPS user community has a large
civil component. In the 1977 National Plan for Navigation, published by the U. S.
Department of Transportation (DoT), the NAVSTAR GPS user community was
planned to include 27,000 military receivers. While the potential for a civil-sector user
base was recognized, the document did not include plans for a civil GPS service
(U.S. DoT 19773-14; 3-15). A decade later the Federal Radio navigation Plan (FRP)
(U.S. DoD and DoT 1986) stated that GPS would be available to civil users,
worldwide, on a continuous basis but with accuracy limited to 100 meters (95
percent).
GPS.pdf (Size: 1.73 MB / Downloads: 156)
Introduction
Have you ever been lost and wished there was an easy way you needed to go?
Ever find that perfect fishing or hunting spot and not been able to remember how to
get back to it easily?
How about finding yourself out hiking and not knowing which direction you should
go to get back to your camp or car?
Ever been flying along and needed to locate the nearest airspace you were in?
Maybe you've been faced with the fact that it's time to pull over and ask someone for
directions.
Global Positioning System technology is rapidly changing how people find their way
around the earth. Whether it is for fun, saving lives, getting there faster, or whatever
uses you can dream up, GPS navigation is becoming more common everyday.
Understanding the principle of GPS Technology Theory :
The Global Positioning System (GPS) is and earth orbiting-satellite based navigation
system. GPS is an operational system, providing users worldwide with twenty-four
hour a day precise position in three dimensions and precise time traceable to global
time standards. GPS is operated by the United States Air Force under the direction of
the Department of Defense (DoD) and was designed for, and remains under the
control of, the United States military. While there are now many thousands of
commercial and recreational civil user’s worldwide, DoD control still impacts many
aspects of GPS planning, operation, and use. Primarily designed as a land, marine,
and aviation navigation system, GPS applications have expanded to include
surveying, space navigation, automatic vehicle monitoring, emergency services
dispatching, mapping, and geographic information system georeferencing. Because
the dissemination of precise time is an integral part of GPS, a large community of
precise time, time interval, and frequency standard users has come to depend on GPS
as a primary source of control traceable through the United States Naval Observatory
to global time and frequency standards.
History of GPS :
Developed in the 1960s, the Navy Transit satellite navigation system still provides
some service as a two-dimensional (horizontal) positioning system. Good (200 meter)
Transit positioning requires knowledge of the user altitude as well as a model of user
dynamics during the fix, a process of integrating satellite signal Doppler shifts (the
change in received signal frequency caused by the changing range) during the fly-over
of the satellite. Another Navy system, based on the Timation satellites carried stable
clocks (quartz, rubidium, and cesium) over the course of the program in the 1960s and
70s and was the precursor to the precise time capabilities of GPS (Easton 1978). GPS
began in 1973 as a test program using ground-based transmitters at the U. S.
Civil andMilitary GPS :
While controlled and maintained by the DoD, the GPS user community has a large
civil component. In the 1977 National Plan for Navigation, published by the U. S.
Department of Transportation (DoT), the NAVSTAR GPS user community was
planned to include 27,000 military receivers. While the potential for a civil-sector user
base was recognized, the document did not include plans for a civil GPS service
(U.S. DoT 19773-14; 3-15). A decade later the Federal Radio navigation Plan (FRP)
(U.S. DoD and DoT 1986) stated that GPS would be available to civil users,
worldwide, on a continuous basis but with accuracy limited to 100 meters (95
percent).