Contains a detailed explanation on RADAR systems . (Signals and systems.)

2. RAdio Detection And Ranging
 Basic Principle

3. Measurement of Range
𝑅 =
𝐶.𝑡𝑑𝑒𝑙 𝑎 𝑦
2 𝟑 × 𝟏𝟎 𝟖
𝒎𝒔−𝟏

4. Indication of a detected object on the
RADAR interface.

5. Video
Noise Noise & Clutter Noise & Clutter

6. Rain
Sea Clutter
Targets
(vessels)

7. Fully Coherent RADAR

8. What is Coherent RADAR
1.PRT
2.PRT
3.PRT
non-coherent pulses with random phase from pulse to
pulse
pulse to pulse phase coherence

9. Functional Block Diagram

10. Duplexer
Power
Amplifier
Up-
converter
Mixer
Low-Noise
Preamplifier
First IF
Amplifier
Frequency
Synthesizer
Waveform
Generator
Up-
converter
Master
Oscillator
Second IF-
Amplifier
Synchronous
Detector
Radar Signal
Processor
A/D
Converter
Timing and
Control
TP1
TP6
TP5
TP4
TP3
TP2

11. TRANSMITTER RECEIVER

12. 1. Klystron stage
• Multicavity Power Klystrons
• Repeller Klystron
2 . A travelling wave tube ( twt )
• low-power twt for
receivers
• high-power twt
for transmitters

13. 3. Steady state Amplifier
MESFET
power
amplifier
powersplitter
poweradder
Cluster 1
Cluster 2

14. RADAR wave form
PRF = Pulse Repetition Frequency
PRT = Pulse Repetition Time
𝑃𝑅𝑇 =
1
𝑃𝑅𝐹

15. Best conditions of a waveform used in
RADAR
 Long pulse for long distance
 Short pulse width for high resolution
 Small bandwidth for large dynamic range
𝐷 =
𝑃𝑟 𝑚𝑎𝑥
𝑃𝑟 𝑚𝑖𝑛
( = value of maximum signal power, in which the receiver is not overloaded. )
(= value of minimum signal power, in which the receiver still issues an output
signal.)

16. Compressed High Intensity Radar Pulse (CHIRP)
Generating the “CHIRP”

18. Pulse compression

19. v

23. • Frequency modulation happens in the “MIXER”.

24. Quartz
Generator
Band pass
Filter
Modulo 2
Counter
Mixer Stage
2
BA LD
LD
LD
BA = Buffer Amplifier
LD = Line Driver

32. PROM = PROgrammable Memory
Buffer Amplifier
HY = Hybrid Combiner
Waveform
Amplifier
FF = Flip Flop

40. Exciter

41. LD
PA
LD = Line Driver PA = PreAmplifier

46. 𝒛 = 𝑹 + 𝒋𝝎𝝉
= 𝟎

47. Detector
Video
Amplifier

48. 𝑻 𝑺 =
1
𝒇 𝑺

49. A Typical sampling theorem used in RADAR.
Nyquist-Shannon Sampling Theorem
When sampling a signal at discrete intervals the sampling frequency 𝑓𝑠
must be greater than twice the highest frequency 𝑓𝑚𝑎𝑥 of the input
signal in order to be able to reconstruct the original signal perfectly from
the sampled version.
The minimum sampling frequency 𝑓𝑆 𝑚𝑖𝑛
that allows reconstruction of
the origin signal is known as the Nyquist frequency. Sampling at less
than the Nyquist frequency causes aliasing.
𝑓𝑠 > 2 𝑓𝑚𝑎𝑥

52. False Alarm Rate =
𝐹𝑎𝑙𝑠𝑒 𝑡𝑎𝑟𝑔𝑒𝑡𝑠 𝑝𝑒𝑟 𝑃𝑅𝑇
𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑅𝑎𝑛𝑔𝑒 𝐶𝑒𝑙𝑙𝑠
a. threshold is set too high: Probability of Detection = 20%
b. threshold is set optimal: Probability of Detection = 80%
But one false alarm arises!
False alarm rate = 1 / 666 = 1.5 *10-3
c. threshold is set too low: a large number of false
alarms arises
d. threshold is set variable: constant false-alarm rate

53. RADAR Scope

60. References
• EMERSON, 2016. Radar FAQs. [Online]
Available at: http://www2.emersonprocess.com/en-us/brands/rosemount/level/pages/radar_faq.aspx
[Accessed 26 10 2016].
• SlideShare, 2016. Radar. [Online]
Available at: http://www.slideshare.net/search/slideshow?lang=**&page=2&q=Radar&qid=4af4fc9b-e821-
423d-acdd-ac32cec61f21&searchfrom=header&sort=relevance
[Accessed 29 10 2016].
• Wolf, C., 2016. Radar Basics. [Online]
Available at: http://www.radartutorial.eu/01.basics/!rb02.en.html
[Accessed 28 10 2016].
• Woodford, C., 2016. Radar. [Online]
Available at: http://www.explainthatstuff.com/radar.html
[Accessed 23 10 2016].

61. Beacon MSSR 2000 I
mounted on an ASR-E with
High- and Low- Beam
feedhorns Source: © EADS
THANK YOU
HESHAN PANDIKORALA