11-05-2013, 11:53 AM
Functions of Radar
Functions of Radar.ppt (Size: 795 KB / Downloads: 26)
INTRODUCTION
RADAR is a method of using electromagnetic waves to remote-sense the position, velocity and identifying characteristics of targets.
History of Radar
Radar was developed for military purposes during W. W. II.
The British and US Military used radar to locate ships and airplanes.
During the war, radar operators found annoying blips continually appearing on the radar screen. Scientists had not known that radar would be sensitive enough to detect precipitations.
Today, radar is an essential tool for predicting and analyzing the weather.
Weather Radar
Weather Surveillance Radar, designed in 1957. It became the primary radar for the weather service for nearly 40 years.
NSSL's first Doppler Weather Radar located in Norman, Oklahoma. 1970's research using this radar led to NWS NEXRAD WSR-88D radar network.
The expensive radar equipment is protected by the sphere shaped cover. On the inside it looks similar to this:
Pulse Transmission
Pulse Repetition Time (PRT=1/PRF)
Pulse Width (PW)
Length or duration of a given pulse
PRT is time from beginning of one pulse to the beginning of the next
PRF is frequency at which consecutive pulses are transmitted.
PW can determine the radar’s minimum range resolution.
PRF can determine the radar’s maximum detection range.
Tracking Radar
Tracking radars dwell on individual targets and follow their motion in azimuth, elevation,range and Doppler.
Most tracking radars can follow only a single target.
A few radars can track multiple targets simultaneously. An electronically steered array antenna is used so that beam positions can be moved quickly from one target to another.