An interferogram in radar refers to the output generated by interferometric synthetic aperture radar (INSAR) systems. It is a visual representation that represents the phase difference between two or more radar signals acquired in the same area but at different times or from different viewing angles. The interferogram is created by comparing the phase information of radar waves reflected from the Earth’s surface. It shows variations in the relative positions of surface features over time or due to changes in viewing angle.
Interferograms are widely used in geodesy, geophysics and environmental monitoring to detect ground deformation, measure topographic changes and study geological processes such as earthquakes and volcanic activity.
An interferometer works by combining two or more coherent waves (such as light or radio waves) to create interference patterns that can be analyzed to extract information about the sources of the waves or the medium through which they propagate. The basic operation of an interferometer is to split a coherent wavefront into two or more pieces using beam splitters or mirrors.
These parts travel different paths and are then recombined to interfere with each other. The resulting interference pattern is detected and analyzed to measure parameters such as phase shifts, path differences or wavelength changes.
Interferometers are used in a variety of applications ranging from optical metrology and astronomy to radar imaging and telecommunications, where precise measurement of distances, displacements or wave characteristics is required.
Interferometric phase refers to the phase difference between two or more coherent waves that are combined in an interferometric or interferometric system. In interferometry, the phase difference occurs due to variations in the path length traveled by the waves or changes in the properties of the medium through which they propagate.
The interferometric phase is crucial to determine the characteristics of the interference pattern observed at the detector. It provides valuable information about the relative positions of sources or reflectors, changes in distance or displacement, and other physical parameters of interest. In radar interferometry (INSAR), for example, the interferometric phase is used to create interferograms that visualize ground deformation or topographic changes over time.
The phase difference is measured and analyzed to derive precise measurements of surface elevation, motion or deformation, making interferometric phase analysis a powerful tool in remote sensing and geospatial applications
