Radar signal processing

1. PRESENTED BY:
Mustahid ALI

2. WHAT IS RADAR?
RADAR (Radio Detection And Ranging) is a
way to detect and study far off targets by
transmitting a radio pulse in the direction of
the target and observing the reflection of the
wave.

3. Propagation
a
Antenn
Target
Cross
Section
Transmitted
Pulse
Reflected
Pulse
(“echo”)
Radar observables:
• Target range
• Target angles (azimuth & elevation)
• Target size (radar cross section)
• Target speed (Doppler)

4. RADAR SIGNAL PROCESSING
a) Distance Measurement
1. transit time
2. frequency modulation
b) Speed measurement
c) Reduction of interference effects
d) Plot and track extraction

5. DISTANCE MEASUREMENT
Transit time:
1.The round trip time for the radar pulse to get to
the target and return is measured.
2.The distance is proportional to this time.
3. The distance is one half the product of the round
trip time and the speed of the signal.

6. Radar Range Measurement
n
Ra
ge
Target
d
itte
sm
an lse
Tr Pu
ted
ec
fl
Re ulse
P
cτ
• Target range = 2
where c = speed of light
τ = round trip time

7. FREQUENCY MODULATION
Another form of distance measuring radar is based on
frequency modulation.
Frequency comparison between two signals is
considerably more accurate, even with older
electronics, than timing the signal.
By measuring the frequency of the returned signal
and comparing that with the original, the difference
can be easily measured.

8. 2. Speed measurement
Speed is the change in distance to an object with
respect to time.
 Thus the existing system for measuring distance,
combined with a memory capacity to see where
the target last was, is enough to measure speed.
There is another effect that can be used to make
almost instant speed measurements known as the
Doppler effect.

9. REDUCTION OF INTERFERENCE
EFFECTS:
Signal processing is employed in radar systems to
reduce the radar interference effects.
Signal processing technique include MTI, pulse
Doppler, constant false alarm rate and digital terrain
model(DTM) are also used in clutter environments.

10. Doppler effect:
The Doppler effect is a frequency shift that results
from relative motion between a frequency source and
a listener.
The Doppler shift is directly proportional to speed
between source and listener, frequency of the source,
and the speed the wave travels.

11. RADAR SIGNAL PROCESSOR

12. The signal processor is that part of the system which
separates targets from clutter on the basis of Doppler
content and amplitude characteristics.
In modern radar sets the conversion of radar signals
to digital form is typically accomplished after IF
amplification and phase sensitive detection.

13. Military application
Navigational radars
Radar altimeters
Air traffic control
Law enforcement and highway safety