Global Positioning System (GPS)
In this cutting edge era we have to heard these three letters in many aspect of our life in many aspects of usability, starting from security workers who receive information thru satellite to an end user like us want to have the facility as much as possible like in the form of some device in our car, watches or in mobile phones.
We discuss all of the hidden but eye opening fact in the light of researches made by the people with their names (in last of the article) and institute. (they deserve the credit in real)
Here we are starting from the beginning of the topic
which we heard as GPS.
For your knowledge the system is for satellite navigation and in real it was designed for military (UNITED STATES) , meanwhile it is controlled by DOD Department of defense of U S.
Satellite signals are received through the GPS receivers then processed and computed for positions, time and velocity.
GPS satellite signals are used to compute positions in three dimensions and the time offset in the receiver clock.
Space Segment:
Is actually Global positioning system satellite which are responsible for sending radio waves (space vehicles are used for). The nominal GPS Operational Constellation consists of 24 satellites that orbit the earth in 12 hours.
There are often more than 24 operational satellites as new ones are launched to replace older satellites. The satellite orbits repeat almost the same ground track (as the earth turns beneath them) once each day. The orbit altitude is such that the satellites repeat the same track and configuration over any point approximately each 24 hours (4 minutes earlier each day).
There are six orbital planes (with nominally four SVs in each), equally spaced (60 degrees apart), and inclined at about fifty-five degrees with respect to the equatorial plane. This constellation provides the user with between five and eight SVs visible from any point on the earth.
Control Segment:
The Control Segment consists of a system of tracking
stations located around the world.
The Master Control facility is located at Schreiber Air Force Base (formerly
Falcon AFB) in Colorado. These monitor stations measure signals from the SVs
which are incorporated into orbital models for each satellites.
The models compute precise orbital data (ephemeris) and SV clock corrections for
each satellite. The Master Control station uploads ephemeris and clock data to
the SVs. The SVs then send subsets of the orbital ephemeris data to GPS
receivers over radio signals.
User Segment:
The GPS User Segment consists of the GPS receivers and the user community. GPS receivers convert SV signals into position, velocity, and time estimates. Four satellites are required to compute the four dimensions of X, Y, Z (position) and Time. GPS receivers are used for navigation, positioning, time dissemination, and other research.
Navigation in three dimensions is the primary function of GPS. Navigation receivers are made for aircraft, ships, ground vehicles, and for hand carrying by individuals.
