Lecture 17: Imaging Radar & LiDAR

Last lecture – Forest remote sensing, Van Kane

Tuesday 3 March

San Francisco

Lecture 17: Imaging Radar & LiDAR

READING

Ch. 8.1 - 8.5 Radar Basics (p.626 – 648)Ch 8.20 - Passive microwave (p. 709 - 714)

Ch. 8.21 - LiDAR (p. 714 - 726)

Radar tutorials:http://satftp.soest.hawaii.edu/space/hawaii/vfts/kilauea/radar_ex/intro.htmlhttp://www.fas.org/irp/imint/docs/rst/Sect8/Sect8_1.htmlhttp://southport.jpl.nasa.gov/index.html

Ch. 5.8 – 5.10 – Thermal Radiation Principles (p. 352 - 374)

http://rst.gsfc.nasa.gov/Sect9/Sect9_1.html

Radar WavelengthsMicrowave spectral region

Passive Microwave

Side-Looking Radar Principle

2ctd =

In aircraft and weather radars, the view is generally straight ahead, and the antenna is rotated to give a spatial pattern.

In remote sensing, the view is to the side and the motion of the airplane or spacecraft allows an image to be built up, line by line.

Synthetic Aperture Radar

Foreshortening, Layover, and Shadowing

β

RadarAir foto

βββ

Styles of radar return (backscatter)

Surface Roughness and Backscatter

Rough is defined with respect to the wavelength of the radar.

βλsin4.4

⟩hβ

λsin25

⟨h

Ih

cos8λ

⟩Rayleighcriterion

h = rms heightI = incidence angleβ = depression angle

Effects of Look Angle

Effect of Wavelength

Two main factors:

(1) Response to roughness

(2) Penetration of vegetation canopy and ground

Brazil - Forest Inundation

Example of Radar Penetration from the Sahara

R-LhhG-ChhB-Chv

TM image Radar image

Layover example -Mt. Shasta

Owens Valley

Mt. Rainier

R - Lhh, G - Lhv, B - Chv

Death Valley - Furnace Creek

R - LhhG - LhvB - Chv

Death Valley Field Sites

Power Spectra of Surface Roughness

Speckle

SAR Interferometry

Interference patterns

Radar Interferometry - fringes

Interferogram Examples

Differential SAR Interferometry

Lidar and vegetation canopies

Lidar for the South End of Bainbridge

Island

Next lecture – Thermal imaging