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ST2276
Scientech Technologies Pvt. Ltd.
52
GPS Glossary
Glossary of terms :
Accuracy :
The degree of conformance between the estimated or measured position, time, and/or
velocity of a GPS receiver and its true time, position, and/or velocity as compared
with a constant standard. Radio navigation system accuracy is usually presented as a
statistical measure of system error and is characterized as follows:
1.
Predictable : The accuracy of a radio navigation system’s position solution with
respect to the charted solution. Both the position solution and the chart must be
based upon the same geodetic datum.
2.
Repeatable : The accuracy with which a user can return to a position whose co-
ordinates have been measured at a previous time with the same navigation
system.
3.
Relative : The accuracy with which a user can measure position relative to that
of another user of the same navigation system at the same time.
Analog :
A type of transmission characterized by variable waveforms representing information,
contrasted with digital. A standard clock with moving hands is an analog device,
whereas a clock with displayed and changing numbers is a digital device. The human
voice and audible sounds are analog. Modem computers are invariably digital, but
when they communicate over telephone lines, their signals must be converted to
analog using a modem (a modulator/demodulator). The analog signal is converted
back into a digital form before delivering it to a destination computer.
Application software :
These programs accomplish the specialized tasks of the user, while operating system
software allows the computer to work. A computer-aided dispatch system is
application software, as is each word processing program.
Automatic Vehicle Location – AVL :
A type of system using any sort of technology to track or locate a vehicle.
Availability :
The percentage of time that the services of a navigation system can be used within a
particular coverage area. Signal availability is the percentage of time that navigational
signals transmitted from external sources are available for use. Availability is a
function of both the physical characteristics of the operational environment and the
technical capabilities of the transmitter facilities.
Bandwidth :
The range of frequencies in a signal.
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