Presentation on RFID and GPS

inspectorwormsΗλεκτρονική - Συσκευές

27 Νοε 2013 (πριν από 3 χρόνια και 10 μήνες)

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Presentation on RFID and GPS

Fletcher Bacon


GPS

Definition


Short for
G
lobal
P
ositioning
S
ystem, a worldwide MEO satellite navigational system formed by 24
satellites orbiting the earth and their corresponding receivers on the earth. The satellites orbit the
earth at approximately 12,000 miles above the surface and make two complete orbits every 24
hours. The GPS satellites continuously transmit digital radio signals that contain data on the
satellites location and the exact time to the earth
-
bound receivers. The satellites are equipped with
atomic clocks that are precise to within a billionth of a second. Based on this information the
receivers know how long it takes for the signal to reach the receiver on earth. As each signal travels
at the speed of light, the longer it takes the receiver to get the signal, the farther away the satellite
is. By knowing how far away a satellite is, the receiver knows that it is located somewhere on the
surface of an imaginary sphere centered at the satellite. By using three satellites, GPS can calculate
the longitude and latitude of the receiver based on where the three spheres intersect. By using four
satellites, GPS can also determine altitude.


GPS was developed and is operated by the U.S. Department of Defense. It was originally called
NAVSTAR (Navigation System with Timing and Ranging). Before its civilian applications, GPS was
used to provide all
-
weather round
-
the
-
clock navigation capabilities for military ground, sea, and air
forces.


GPS has applications beyond navigation and location determination. GPS can be used for
cartography, forestry, mineral exploration, wildlife habitation management, monitoring the
movement of people and things and bringing precise timing to the world.




RFID

An ideal world,

what issues can

you think of?

Definition


(pronounced as separate letters) Short for
R
adio
F
requency
ID
entification
, a technology similar in
theory to bar code identification. With RFID, the electromagnetic or electrostatic coupling in the RF
portion of the electromagnetic spectrum is used to transmit signals. An RFID system consists of an
antenna and a transceiver, which read the radio frequency and transfer the information to a
processing device, and a transponder, or tag, which is an integrated circuit containing the RF
circuitry and information to be transmitted.


RFID systems can be used just about anywhere, from clothing tags to missiles to pet tags to food
--

anywhere that a unique identification system is needed. The tag can carry information as simple as
a pet owners name and address or the cleaning instruction on a sweater to as complex as
instructions on how to assemble a car. Some auto manufacturers use RFID systems to move cars
through an assembly line. At each successive stage of production, the RFID tag tells the computers
what the next step of automated assembly is.


One of the key differences between RFID and bar code technology is RFID eliminates the need for
line
-
of
-
sight reading that bar coding depends on. Also, RFID scanning can be done at greater
distances than bar code scanning. High frequency RFID systems (850 MHz to 950 MHz and 2.4 GHz
to 2.5 GHz) offer transmission ranges of more than 90 feet, although wavelengths in the 2.4 GHz
range are absorbed by water (the human body) and therefore has limitations.


RFID is also called dedicated short range communication (DSRC).