Radar-Verfahren und -Signalverarbeitung › media › ei › lehrma...Ender: Radarverfahren - 3 - Radar –human Eye Both generate an image of the environment, but: Different frequencies:

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

[email protected]

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)


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


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


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


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


GERMAN AIRBORNE MULTI-PHASE-CENTER RADAR "Lichtenstein" (1944)


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


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


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


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


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


TODAY: OPERATIONAL SPACE-BASED SAR SYSTEMS

TerraSAR-X RADARSAT-2

SAR-Lupe

COSMO-SkyMED

TanDEM-XTanDEM-LSentinel-1

FUTURE


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


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


SAR-INTERFEROMETRY

Range

SAR AND MOVING TARGETS

Ship lock

Brunsbüttel

Azimuth

Ship lockBrunsbüttel

SAR AND MOVING TARGETS

ATIShip lock

Brunsbüttel

ALONG TRACK INTERFEROMETRY


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

http://airsar.jpl.nasa.gov/news/atifigs.pdf


GMTI-RESULTS INCLUDING SAR CONTEXT

Accumulated detections Targets with established tracks


ENHANCED MODES: GMTI WITH TWO SATELLITES

TanDEM-X (second TerraSAR-X) satellite

was launched in 2010

© ASTRIUM

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Radar-Verfahren und -Signalverarbeitung › media › ei › lehrma...Ender: Radarverfahren - 3 - Radar –human Eye Both generate an image of the environment, but: Different frequencies: