How do you interpret an interferogram?
The first step in reading an interferogram is to determine “when” and “what”. The dates of each image answer the question of “when” the deformation occurred. Different satellites use different wavelengths, and that controls the amount of ground deformation represented per colored fringe—the “what”.
What is interferogram InSAR?
In an interferogram, the two SAR images are aligned on a pixel-by-pixel basis and the fringe color cycles represent units of the radar wavelength. The image can be read much like a topographic map, whereby the difference in surface displacement can be ascertained by the spread of the fringes.
What does an interferometer do?
Because of their wide application, interferometers come in a variety of shapes and sizes. They are used to measure everything from the smallest variations on the surface of a microscopic organism, to the structure of enormous expanses of gas and dust in the distant Universe, and now, to detect gravitational waves.
How is an interferogram created?
An interferogram is generated by making measurements of the signal at many discrete positions of the moving mirror. A Fourier transform converts the interferogram into an actual spectrum.
What is InSAR used to measure?
InSAR is ideally suited to measure the spatial extent and magnitude of surface deformation associated with fluid extraction and natural hazards (earthquakes, volcanoes, landslides).
How accurate is InSAR?
Data of InSAR monitoring system were observed for one year. The current InSAR results are shown in the Figure 12. Generally, we can say the accuracy of BDS Navigation Satellite System is smaller than 3.4 mm when the length of baseline is 3.1 km.
What is radar interferogram select one?
Differential radar interferometry is a technique for mapping surface deformation from archived SAR data, suitable primarily for measuring movements of several millimeters to a few dozen centimeters that cover an area greater than one hundred meters.
How accurate are interferometers?
How accurate are interferometers? A state-of-the-art interferometer can measure distances to within 1 nanometer (one billionth of a meter, which is about the width of 10 hydrogen atoms), but like any other kind of measurement, it’s subject to errors.