To obtain high resolution we need to transmit a narrow beam by reducing a beam width, but the size of an antenna must be large to obtain greater directivity. If the radar which actually transmits a radio wave from a satellite has the antenna directivity required to obtain the resolution more than 10m on the ground, the size of an antenna, which is called "aperture", becomes more than 1km and is impractical to install on a satellite.
So, there is a technology which artificially "synthesizes" an "aperture" using a flying object satellites or airplanes that transmits and receives a radio wave during flight in order to obtain an image equivalent to one acquired by an antenna with a big aperture size. It is called "synthetic aperture radar". As shown in Figure2, even if the antenna whose aperture size is actually small is used, the resolution in the direction of a fright track is improved by the synthetic aperture technology which makes up a virtual antenna with a big aperture size by transmitting and receiving radio waves during flight.
- Divine Command Ethics: Jewish and Christian Perspectives (Philosophical Ideas in Debate).
- Part A-InSAR Principles-Guidelines for SAR Interferometry-Processing and Interpretation.pdf!
- Explore Earth Online.
- Professional PHP Programming.
Figure 2. Resolution improvement by the synthetic aperture technology. However, we cannot improve the resolution of the direction orthogonal to a flight track only by using the synthetic aperture technology.
In a given image, the phase for each individual pixel is determined by the distance of the pixel from the radar and the backscatter from the pixel surface. If the backscatter remains constant over the time-period covering the acquisition dates of the two images in other words if the dielectric properties of the pixel surface and the geometry of the elementary backscatter within the pixel remain constant then the resulting difference in phase between the two images for each pixel has three possible origins:. If the satellite orbit geometry and the topography DEM are precisely constrained then their respective contributions can be removed from the interferogram point 1.
In addition, if the difference in atmospheric conditions between the acquisition of the master and slave images is negligible point 3 , then the observed phase shifts on the interferogram must be a direct effect of ground deformations which took place between the two acquisition dates. These phase shifts are generally assembled into regular variations on the interferogram known as fringes.
Monitoring the Earth Deformation from Space
To remove this ambiguity the interferogram is subjected to an unwrapping treatment. The E-mail Address es you entered is are not in a valid format.
- The Cannabis Manifesto: A New Paradigm for Wellness.
- Duplicate citations.
- Andrea Monti-Guarnieri - Google Scholar Citations!
- Search form.
- Duplicate citations?
Please re-enter recipient e-mail address es. You may send this item to up to five recipients.
Citations per year
The name field is required. Please enter your name. The E-mail message field is required. Please enter the message.
InSAR Principles: Guidelines for SAR Interferometry Processing and - Google книги
Please verify that you are not a robot. Would you also like to submit a review for this item?
You already recently rated this item. Your rating has been recorded.
Write a review Rate this item: 1 2 3 4 5. Preview this item Preview this item. Subjects Synthetic aperture radar.
View all subjects More like this Similar Items. Find a copy online Links to this item esa. Allow this favorite library to be seen by others Keep this favorite library private. Find a copy in the library Finding libraries that hold this item Find more information about: Karen Fletcher.