1. REMS 6022 – Lab 4 NEST – Interferometric Synthetic Aperture Radar Exercises
I hope its ok to do these InSAR exercises as the lab. I kept getting errors in the oil slick lab. It wouldn’t let me proceed past the oil detection tool, the software kept crashing.
Venessa Bennett

2. InSAR Course - Overview
Two training exercises are summarized in the following presentation. The exercise represent training in the use of the NEST SAR toolbox developed by ESA. Exercise 1 is the generation of an Interferogram on Etna Volcano and exercise 2 is the generation of an interferogram of the BAM earthquake.
BACKGROUND
Radar interferometry: Study of interference patterns caused created by combining two sets of radar signals.
Interferogram: When two interferometric radar data sets are combined the first product made is called an interferogram

3. InSAR - Theory
Interferometric Synthetic Aperture Radar (InSAR) is a geodetic technique that can identify movements of the Earth's surface
Observations of surface movement made using InSAR can be used to detect, measure, and monitor crustal changes associated with geophysical processes such as tectonic activity and volcanic eruptions
Ground subsidence caused by anthropogenic influences such as groundwater or hydrocarbon extraction can also be identified with InSAR
When combined with ground-based geodetic monitoring, such as GPS, InSAR can identify surface movements of millimetre to centimetre scale with high spatial resolution.
SOURCE:

4. InSAR - Theory
InSAR uses two or more Synthetic Aperture Radar (SAR) images of an area to identify surface movements through time.
Remote sensing satellites that collect SAR imagery transmit pulses of microwave energy to the Earth's surface and record the amount of backscattered energy.
SAR images contain information on the Earth's surface in the form of the amplitude and phase components of the backscattered radar signal
The amplitude image records information on the terrain slope and surface roughness, while the phase image records information on the distance between the satellite and the Earth's surface.
SOURCE:

5. InSAR - Theory
Differential InSAR uses two SAR images of the same area acquired at different times. If the distance between the ground and satellite changes between the two acquisitions due to surface movement, a phase shift will occur
SOURCE:

6. InSAR - Theory

7. InSAR - Theory

8. InSAR - Theory

9. IMAGE 1 Acquisition start : 01-Aug-1995 21:16:47.897
Exercise 1: Generation of an interferogram on ETNA Vulcano, Sicily (Italy), using a ERS1&2 couple acquired on 1/2 August 1996.
IMAGE 1 Acquisition start : 01-Aug :16:47.897
IMAGE 2 Acquisition start: 02-Aug :16:50.666
STEPS
1. DATA PREPARATION
Load data
Create new project
Apply ephemeris information to data
coregister both input images (cubic convolution resampling method)
2. GENERATE INTERFEROGRAM
Use InSAR Tools to generate flattened interferogram
Estimate coherence between 2 input images and compare two images
(two wave sources are coherent if they have a constant phase difference and the same frequency)
Carry out topographic phase removal
Complete multilook analysis
Geocode and Review in Google Earth

10. Mt Etna Interferograms

11. Mt Etna Interferogram Coherence

12. Mt Etna Interferogram vs Coherence

13. Mt Etna Topographic Phase Removal

15. Mt Etna Topographic Phase Removal

16. Does not work in NEST 5.1 as in NEST 4B-1
Mt Etna Multilook
Does not work in NEST 5.1 as in NEST 4B-1

17. Mt Etna Geocode and Review in Google Earth

18. Exercise 2: Generation of DInSAR inteferogram of the BAM earthquake
IMAGE 1 Acquisition start 03-Dec :13:06.358
IMAGE 2 Acquisition start: 11-Feb :13:03.504
Graph builder is used to process the data
1. DATA PREPARATION
Load data
Create new project
coregister both input images (cubic convolution resampling method)
2. GENERATE INTERFEROGRAM
Use InSAR Tools to generate flattened interferogram
Estimate coherence between 2 input images and compare two images
3. Hue Saturation Intensity Visualization

19. Graph Builder Model

20. BAM flattened Interferogram & Coherence Images

21. Mt Etna Interferogram vs Coherence

22. HSV Visualization