7/29/2019 Search Radar
1/23
BY
H.S.VARA PRASAD
7/29/2019 Search Radar
2/23
Introduction
Basic radars.
Types of Radar.
Search Radar
Moving Target
Indication
Scan with search
radar
Search Radar
equation
Conclusion
7/29/2019 Search Radar
3/23
7/29/2019 Search Radar
4/23
MONO STATIC RADAR
BI-STATIC RADAR
CW- RADAR
FM-CW RADAR
PULSED RADAR (search radar)
7/29/2019 Search Radar
5/23
R=CTR
2
7/29/2019 Search Radar
6/23
7/29/2019 Search Radar
7/23
7/29/2019 Search Radar
8/23
Search radars scan a large area withpulses of short radio waves
Targeting radars use the same principlebut scan a smaller area more often
Navigational radars are like searchradar, but use short waves that reflect offhard surfaces. They are used oncommercial ships and long-distance
commercial aircraft
7/29/2019 Search Radar
9/23
only detecting target
Operated only in search
or acquisition mode.
it will have knowledgeof other potential target.
An antenna with narrow
pencil beam is sufficient
for finding the target
both detecting and tracking.
Operated in both search
and tracking mode.
in tracking mode , it has noidea of other potential targets
An antenna with narrow
pencil beam is not sufficient for
detecting and ranging. thereforeseparate radar is used for
searching
7/29/2019 Search Radar
10/23
-Pulse radar that utilizes doppler frequencyshift as a means of discriminating moving
from a fixed targets is called MTI
-Blind speeds ( ambiguous Doppler
measurement )
-2nd
time around echoes (unambiguous rangemeasurement) depends on p.r.f
7/29/2019 Search Radar
11/23
The blind speed is a radial speed of the airplane at which
the phase shifting of the echo-signal has the valuen 360between two pulse periods. With blind speeds
moving targets are suppressed by a MTI system like ground
clutters.
Blind Phases:
It is due to the presenceof sampling pulses at the
point in the Doppler cycle
at each sampling instant
7/29/2019 Search Radar
12/23
Block Diagram of MTI
7/29/2019 Search Radar
13/23
Block Diagram of MTI
with power amplifier
7/29/2019 Search Radar
14/23
Block Diagram of MTI
with power amplifier
7/29/2019 Search Radar
15/23
7/29/2019 Search Radar
16/23
Search radars are systems devoted to thesystematic exploration of a large volume ofspace
for typical air search radars, this is performed
over 360 in azimuth and over elevation anglesranging from 20-30 up to almost 90,
processing the echoes over the whole PRI, i.e.
over the whole observable range
a search radar has large beam in elevation
and has a stacked beams in azimuth the beam
steered both in elevation and azimuth in search
radar.
The search volume indicated solid angle
7/29/2019 Search Radar
17/23
MODE:
1.Circular scan
2.Sector scan
3.Tracking scan
4.Dopplerscan
Gain
Sweep
frequency
steradiansAZ EL
7/29/2019 Search Radar
18/23
R
180
90100
1
2
Search Sector
=azal
steradiansAZ EL
1
2
and the elevation extent goes from
to
.
1
2
and the elevation extent goes from
to
.
=azimuthal
extent from 1
to 2
7/29/2019 Search Radar
19/23
The powerP
rreturning to the receiving antenna is
given by the equation:
Where Pt = transmitter power
Gt = gain of the transmitting antenna
Ar= effective aperture (area) of the receiving antenna
= radar cross section, or scattering coefficient, of the target
F= pattern propagation factor
R = distance from the transmitter to the target
7/29/2019 Search Radar
20/23
7/29/2019 Search Radar
21/23
There are several search
radar like surveillance search
radar ,navigation searchradar are extending their
services to both military and
civilian applications
7/29/2019 Search Radar
22/23
7/29/2019 Search Radar
23/23