4: The Radar Equation
The Radar Equation
The Radar Equation"
Radar Cross Section"
Pattern propagation factor"
The Radar Equation
Consider an isotropic antenna, fed with a transmit power Pt ."
3. Radar Basics - 2
ERS-1 Earth Resources Satellite
SEASAT Shuttle SAR Image
Terra SAR - X
Airborne SAR Image of the
source: Sandia Corporation -http/www.sandia.gov !
Radar Equipment Rack
RAN 20 S, radar electronic cabinet includ
2. Radar Basics - 1
What is Radar?
Transmission and reception of Electro-Magnetic
radiation via echo location."
Collimated into a beam and scanned"
Usually pulsed and many pulses per second"
Detects objects and their location."
19: Bistatic radar 3
Illuminators of Opportunity
Illuminators of Opportunity
In general, bistatic radar systems will use dedicated radar transmitters with explicit control
over location, modulation, scan pattern, etc.!
However, it is also possible to us
17: Bistatic Radar - 1
Bistatic radar may be dened as a radar system in
which the transmitter and receiver are not co-located."
This is a somewhat imprecise denition (Theres a
prize for someone coming up with one that is)"
The subject has
16. Aviation Radar Systems - 2
Primary ATC Radar
Terminal Area Weather Radar
Suitably designed weather radar can give information on
a range of meteorological phenomena of interest to air
trafc control centres. "
These include identication of areas of he
15. Aviation Radar Systems - 1
Aviation Radar and Air Traffic Control
An Air Route Traffic Control Center
Aviation Radar part I
Air traffic control and management
Primary ATC radar: area/approach, surface movement and
terminal weather rad
14. DPCA and STAP
Consider one antenna carried on an aircraft looking out sideways to the
direction of travel. The clutter collected will have a radial velocity
component due to the nite beam-width and the forward motion of the
11: FM cw Radar
9. FM cw Radar
Equivalence to pulse compression"
Digital generation of wideband chirp signals "
FM cw Radar
FM cw Radar is a low cost technique,
11. Waveforms, Design and Diversity
Waveforms, Design and Diversity
Linear period modulation!
Step-CW and step-chirp!
Phase Coded Pulse Compression
In contrast to analogue linear-FM pulse compression, it is eq
9. Pulse Compression
Introduction: The Waveform
Waveform design has always taken into account:"
A wide variety of waveform design h
The Radar Receiver
The radar receiver detects echoes, down-converts them stripping
off the carrier and revealing the imposed modulation.!
It will consist of a Low Noise Amplier (LNA), band pass lter,
mixer/s and digitizer!
In modern ra
The Radar Transmitter
The Radar Transmitter:!
Generates high power RF radiation which illuminates targets and
scenes of interest.!
Includes three basic elements; (i) The power amplier, (ii) the
modulator and (iii) the power supply.!
4.1 Cathode Ray Tubes
4.2 Types of display
4.3 Modern displays
Displays are used to present in visual form the information contained in the
radar echo signal, i.e. in a form suitable for operator interpretation and
6: Noise, Clutter and Detection - 2
The properties of sea clutter will depend on a wide variety of parameters: the
radar parameters !
!frequency, polarization, resolution (in range and azimuth), incidence
and the surface paramete
5: Noise, Clutter and Detection - 1
Noise and statistics!
Detection against noise!
Clutter and clutter models!
Computer simulation of radar performance!
If you were to look at noise on an!
oscilloscope, you d se
There has been much media interest in stealth and stealthy aircraft in the past ten years or so, and claims are made that such targets are invisible to radar . Not surprisingly, much of this is rubbish ! This section looks at the techn
33. Target Classification - 2
Main rotor hub
Tail rotor blades Main rotor blades
Helicopter mechanics: Main rotor blade acts as rotary wing and gives helicopter lift Tail rotor provide stability by reducing turning moment Jet eng
32. Target Classification - 1
Classification: Military Need Targeting!
reduction of cockpit load for fast-jet targeting applications"
operator aids to address data deluge problem" region-of-interest compression for limited UAV data-links"
31: SAR 2b
Inverse Synthetic Aperture Radar (ISAR)
Instead of using a moving radar, the radar can be held stationary and the target moved.! ! Two cases can be distinguished:! ! co-operative ISAR, in which the target motion (usually rotation) is controlled
30: SAR 3
Interferometric SAR - Geometry
interferometric phase =
.Q. ( r2 - r1 )
(Q=1 for single-pass, 2 for double-pass)
12 .Q. ( r12 - B 2 - 2r1B cos ( + ) ) - r1
.Q.B cos ( + )
(valid at long range or for large)
27. High Resolution Radar - 1
Why Radar Imaging?
All weather" Day and Night operation" Wide area" High resolution improves information content" Easier interpretation" Object classification"
Ohio State University
r radar! pulse ! point targ
26. Tracking - 2
Tracking measured position xn-xp smoothed track
predicted position New smoothed position xs=xp+ (xn-xp) xp= next predicted position of the target xn= measured target position
Tracking New smoothed positio
24. Electronic Scanning 3
THE BEAM STEERING CONTROLLER The beam steering controller consists of a computer to calculate the phase shifts settings required for the phase shifters, the driver to set the phase shifters and data bus to send sign
23. Electronic Scanning - 2
Phased Array Theory
CALCULATION OF SIDELOBES
Ps 4 SLave = * s Pt
SLave = Pt - Pmainbeam 4 * 4 - mainbeam Pt
SL ave PS Pt Pmainbeam s mainbam
Is the ave sidelobe power wrt isotropic is the power in the sidelobes is the tot