Post on 03-Jul-2020
Radar-Verfahren und -Signalverarbeitung
- Lesson 1: Introduction
Hon.-Prof. Dr.-Ing. Joachim Ender
Head of
Fraunhoferinstitut für Hochfrequenzphysik and Radartechnik FHR
Neuenahrer Str. 20, 53343 Wachtberg
joachim.ender@fhr.fraunhofer.de
Ender: Radarverfahren- 2 -
• Radar system:
- Waveform generator –transmitter – object – receiving antenna – receiver – signal processing
• Measurement:
- Distance to object
- Direction
- Velocity
- Doppler frequency
- Signatures
- Imaging
Receiver
„Mathematics“
A/D converter
• The ‘digital revolution’:
RADIO DETECTION AND RANGING (RADAR)
Ender: Radarverfahren- 3 -
Radar Radar –– human Eyehuman Eye
Both generate an image of the environment, but:
Different frequencies:
● Unusual reflectivity distribution
● Clouds, fog, dust and other materials are penetrated
Active system● Independent on the day light, operation at day and night
Small relative bandwidth (for classical radar)
● Interference effects, speckling
● Specular reflections
Ender: Radarverfahren- 4 -
THE HISTORY OF RADAR
Heinrich Hertz 1886
Christian Hülsmeyer 1904
Influence of a communication link by an airplane (USA) 1930
Pulse radar (USA, UK, GE, FR, SU) 1934
Operational radar 40th
Signal theory 50th
Imaging Radar (SAR) 1953/54
Digital signal processing 70th
Space based radar systems 1978
Phased arrays 80th
Millimeterwave/solid state transmitters 90th
Digital SAR processors 90th
MMICs 90th
Single-track Interferometrie from space 2000
Tandem satellite configuration 2010
Ender: Radarverfahren- 5 -
Radar system:
Waveform generator
transmitter
object
receiving antenna
receiver
signal processing
Measurements:
Distance to object
Direction
Velocity
Doppler frequency
Signatures
Imaging
RADIO DETECTION AND RANGING (RADAR)
Patent of Christian Hülsmeyer 1904
Pulse radar(USA, UK, GE, FR, SU) 1934
Operational radar 1940th
Imaging Radar (SAR) 1954
Digital signal processing 1970th
Space based radar systems 1978
Phased arrays 1980th
Millimeter wave radars 1980th
Solid state transmitters 1980th
Digital SAR processors 1980th
MMICs 1990th
Single track interferometry from
space
2000
Coherent satellite pair 2010
Ender: Radarverfahren- 6 -
THE INVENTION OF RADAR„Verfahren, um metallische Gegenstände einem entfernten Beobachter zu
melden“ (Patent Hülsmeyer 1904) - "Telemobiloskop"
1881-1957
First demonstration at
the Hohenzollern
Bridge (Cologne) 1904
Ender: Radarverfahren- 7 -
GERMAN AIRBORNE MULTI-PHASE-CENTER RADAR "Lichtenstein" (1944)
Ender: Radarverfahren- 8 -
APPLICATIONS I
Airspace surveillance (primary radar / secondary radar)
● Flugsicherung: Bezirkskontrollstellen (1 GHz, 150 NM), Anflugkontrollstellen (3 GHz, 60 NM), Rollfeldkontrolle (24 – 37 GHz)
Airborne radar
● Air space surveillance, weather radar, navigation radar, altimeter, obstacle warning, imaging radar
Shipping
● Coastal surveillance, anticollision radar, visualisation of river traffic
Street traffic, car equipment
● Police radar, anticollision radar, driver assistance systems, ....
Space
● Surveillance of space objects, docking manoeuvres, exploitation of celestial bodies
Ender: Radarverfahren- 9 -
Remote sensing
-> see SAR applications
Further applications
• Meteorology: Weather radar
• Motion detectors (alarm systems, object protection)
● Ground penetrating radar
● Through-the-wall radar
● Industrial measurements (distance measurement, filling level control)
● Control radar for deformation of buildings
APPLICATIONS II
Ender: Radarverfahren- 10 -
Two sources for distance measurement
Coarse but unambiguous
information by
measurement of the wave
travelling time
(~ meter)
12
6
39
1
2
4
57
8
10
11
Fine but ambiguous
information by phase
measurement (~ mm)
Phase rotation along the
time = Doppler effect
->
Measurement of the radial
velocity
Ender: Radarverfahren- 11 -
Two basic concepts of radar
Radar sensor for object detection and
positioning
Position measurements over time allow
target tracking
The resolution cell (range, direction,
Doppler) are greater or equal to the
object dimensions
Classification by signal strength (RCS),
Doppler modulation, polarisation,
dynamics of motion, polarisation
• Imaging radar
- Generation of a quasi optical
image (SAR, ISAR)
- Resolution cells much smaller than
target dimension
- Classification with range profiles,
radar images
Ender: Radarverfahren- 12 -
FREQUENCY BANDS
Wavelength Frequency from to Band Applications
10 m / 1 m 30 MHz 300 MHz VHF OTH radar, Foliage penetration radar
1 m / 30 cm 300 MHz 1 GHz UHF Airborne Early Warning
30 cm / 15 cm 1 GHz 2 GHz L-Band
The most applications
15 cm / 7,5 cm 2 GHz 4 GHz S-Band
7,5 cm / 3,75 cm 4 GHz 8 GHz C-Band
3,75 cm / 2,5 cm 8 GHz 12 GHz X-Band
2,5 cm / 1,7 cm 12 GHz 18 GHz Ku-Band
1,7 cm / 1,1 cm 18 GHz 27 GHz K-Band resonance of water-vapor
11 mm / 7,5 mm 27 GHz 40 GHz Ka-Band Short-range applications
7,5 mm / 4 mm 40 GHz 75 GHz V-Band absorption by oxygen
4 mm / 2,7 mm 75 GHz 110 GHz W-Band Seeker heads
2,7 mm / 1 mm 110 GHz 300 GHz mm-waves Person scanning, defence against
terrorism < 1 mm more TeraHertz
Ender: Radarverfahren- 13 -
TODAY: OPERATIONAL SPACE-BASED SAR SYSTEMS
TerraSAR-X RADARSAT-2
SAR-Lupe
COSMO-SkyMED
TanDEM-XTanDEM-LSentinel-1
FUTURE
Ender: Radarverfahren- 14 -
SPACE BASED SARINTERFEROMETRIC SENSING AND IMAGING POLARIMETRY
Polarimetric image
of a scene in
Indonesia, ALOS-
PALSAR
2007/3/10
©JAXA, METICourtesy Prof. Börner, Univ. of Illionois
Google earth optical image
N
Ender: Radarverfahren- 15 -
3-color polarization overlay of the Aleutian volcanoes
AIRBORNE SAR2009 UAVSAR DATA ACQUISITIONS, NASA-JPL
3-color polarization overlay of Kangerlugssuaq Glacier in
Greenland
Civilian Global Hawk (UAV)
Courtesy Dr. Paul Rosen, JPL
Ender: Radarverfahren- 16 -
SAR-INTERFEROMETRY
Range
SAR AND MOVING TARGETS
Ship lock
Brunsbüttel
Azimuth
Ship lockBrunsbüttel
SAR AND MOVING TARGETS
ATIShip lock
Brunsbüttel
ALONG TRACK INTERFEROMETRY
Ender: Radarverfahren- 20 -
ATI FOR MEASURING THE OCEAN SURFACE
CURRENTS
Image Source: David A. Imel, Scott Hensley, Brian Pollard, Elaine Chapin, Ernesto Rodriguez (JPL): Along−Track Interferometry; http://airsar.jpl.nasa.gov/news/atifigs.pdf
Ender: Radarverfahren- 21 -
GMTI-RESULTS INCLUDING SAR CONTEXT
Accumulated detections Targets with established tracks
Ender: Radarverfahren- 22 -
ENHANCED MODES: GMTI WITH TWO SATELLITES
TanDEM-X (second TerraSAR-X) satellite
was launched in 2010
© ASTRIUM