what is radar?

Question

nagesh hs
4 th sem
msrit
banglor

Answer 1

Radar is a system that uses radio waves to determine and map the location, direction, and/or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations and terrain. A transmitter emits radio waves, which are reflected by the target and detected by a receiver, typically in the same location as the transmitter. Although the radio signal returned is usually very weak, radio signals can easily be amplified, so radar can detect objects at ranges where other emissions, such as sound or visible light, would be too weak to detect. Radar is used in many contexts, including meteorological detection of precipitation, air traffic control, police detection of speeding traffic, and by the military. The term RADAR was coined in 1941 as an acronym for Radio Detection and Ranging. This acronym of American origin replaced the previously used British abbreviation RDF (Radio Direction Finding). The term has since entered the English language as a standard word, radar, losing the capitalization in the process.

Answer 2

Air traffic control radar uses two types of radar at once:
Primary radar is the parabolic antenna you often see at airports.
The radar transmits brief microwave pulses in a very narrow beam. The radio pulses bounce off the aircraft surface. By knowing the direction the antenna is pointing and how much time passes for the echo to be received, the radar can tell where an airplane is flying and how fast its going. But it can't tell which airplane is which or how high each plane is flying.

That's done with secondary radar using a transponder aboard the airplane, which communicates with radar on the ground. Before flight, the pilot dials a 4-digit number assigned by air traffic control into the transponder. The transponder is also connected to the plane's altimeter.

Once airborne, the aiplane's transponder receives commands from interrogators at ground radar stations and transmits the aircraft ID and altitude. Air traffic control computers identify the plane from that 4-digit number and display a data block showing the plane's ID and altitude. The data block moves across the radar screen with the plane.

Airliners also carry a weather radar system in the plane's nose to indicate severe weather ahead, and a small radar altimeter to indicate the plane's height above ground up to about a couple thousand feet. This is important when landing.

This is a simplified explanation and there are some other radar transponder functions like collision avoidance that would be too difficult to explain here. One good source of reference material on this topic is the US Government publication the "Airmans Information Manual"

Answer 3

Radio Detection And Ranging condensed to RADAR is used to signify radio equipment which uses VHF and higher frequency bands and provides detection and range.

It uses higher freq to derive benefits due to:
a) Less static disturbance and ionospheric scatter
b) Narrow beams
c) Shorter pulses
d) Reflection from small objects

Ranging and Detection: It uses echo principle for ranging and beam principle for detection.

Technique: Two basic techniques on which Radar system functions are Pulse technique and Continuous Wave (CW) technique.

PULSE Technique: The technique involves transmission of tiny bursts of CW in a pre-determined shape.

Pulse Width: It is the duration of one pulse.
a)One pulse may contain many cycles depending upon the frequency being used.
b) If the freq used is 10GHz, it means 10,000,000,000 cycles per second or
10,000 cycles per micro second. Therefore a pulse width of 2 Secs
will have 20,000 cycles.

Answer 4

Radar is a system in which the echoes of transmitted microwave radiations are used to detect and locate distant objects. It is an acronym of Radio Detection and Ranging.

Answer 5

In simple terms radar is an electronic signal sent out in many or all directions to find something. When an object is found the signal is bounced back and you can determine where, what, how far, how strong, how big, it is etc........

Answer 6

Radar is waves that are bounce off an object and returned to the source, to give and indication of the altitude and speed of the object that the waves were bounced off of.

Answer 7

RAdio Detection And Ranging

RA D A R

RADAR

Answer 8

Do you know SONOGRAPHY.
Absolutely same principle of working.The only difference is here instead of sound waves radio Waves are used.range is quite vast.

Answer 9

RADAR is your wife ,
keeping track of your movements,
so as to control you,
ERRRR just a jock.

Answer 10

RADIO DETECTION AND RANGING