Contents
What is InSAR technique?
InSAR (Interferometric Synthetic Aperture Radar) is a technique for mapping ground deformation using radar images of the Earth’s surface that are collected from orbiting satellites. Unlike visible or infrared light, radar waves penetrate most weather clouds and are equally effective in darkness.
What does radar interferometry on satellites see?
Synthetic Aperture Radar (SAR) acquires images of the Earth in the microwave spectrum with wavelengths in the order of centimetres. Electromagnetic waves of this size can penetrate clouds, which makes SAR an all-weather remote sensing system operating day and night.
How can I download InSAR data?
You can download InSAR data from these websites: https://scihub.copernicus.eu/dhus/#/home. Please see ASF Vertex (https://vertex.daac.asf.alaska.edu/) for SAR data from different missions such as ERS, ALOS, Radarsat, and Sentinel-1. Sentinel-1 data can also be downloaded from the Copernicus website.
What is the difference between an active and a passive remote sensor?
Remote sensing systems which measure energy that is naturally available are called passive sensors. Passive sensors can only be used to detect energy when the naturally occurring energy is available. Active sensors, on the other hand, provide their own energy source for illumination.
How is InSAR data collected?
InSAR makes high-density measurements over large areas by using radar signals from Earth-orbiting satellites to measure changes in land-surface altitude at high degrees of measurement resolution and spatial detail ( Galloway and others, 2000 ).
How does the interferometric synthetic aperture radar ( InSAR ) work?
InSAR makes high-density measurements over large areas by using radar signals from Earth-orbiting satellites to measure changes in land-surface altitude at high degrees of measurement resolution and spatial detail ( Galloway and others, 2000 ).
What do you need to know about SAR interferometry?
This training manual introduces and explains Interferometric Synthetic Aperture Radar (InSAR), including applications for data from the Envisat ASAR sensor and how to combine Envisat and ERS images to produce interferograms and differential interferograms. Synthetic Aperture Radar (SAR) is a microwave imaging system.
What is the difference between dinsar and differential interferometry?
Differential interferometry or DInSAR is interferometry itself. The only difference is that topographic effects are compensated by using a Digital Elevation Model (DEM) of the area of interest, creating what is referred to as a differential interferogram. This can be expressed as:
How does the phase of interferometry work in space?
If the same target on Earth is re-acquired from the same point in space, then in theory the total signal distance will be unchanged and the signal phase should remain the same. However the slightest millimetre-scale ground shift occurring between acquisitions will cause the phase to alter.