Synthetic aperture radar images are formed along the slant range. However, The target is on the ground range. So How we change the geometry of the image from the slant range to the ground range.
Hello,
Short, generic answer is to project slant range data into the ground range.
Maryam's suggestion is pretty much OK for flat terrain. For undulating terrain, however, much efforts are needed. Key thing, I guess, is the data themselves. While it is certain that you can get high resolution SAR data easily, conversion to ground range of this data require comparably DEM.
I personally do not recommend non-specialist toolkits such as ENVI (basic) or any GIS software to do this. Instead, freely available SNAP would be perfect for you, available from http://step.esa.int/main/toolboxes/snap/. I did a test on free software for classification purpose using PALSAR SLC data (see http://www.tandfonline.com/doi/abs/10.1080/01431161.2017.1292072). I do think that free software for SAR is maturing.
HTH, Bambang
Depending on the accuracy and precision required, it gets a little more complicated for long ranges where earth curvature and atmospheric refraction become significant. In these cases the attached reports might be useful.
Technical Report Radar Range Measurements in the Atmosphere
Technical Report Earth Curvature and Atmospheric Refraction Effects on Radar ...
It can be also good to look at http://www.worldcat.org/title/understanding-synthetic-aperture-radar-images/oclc/55199498
I recommend you to check my blog post on "Synthetic Aperture RADAR (SAR) Remote Sensing Basics and Applications"
https://geospatialwarehouse.wordpress.com/2017/04/
It is actually not very complicated. Imagine the right-angled triangle RNG where R is the Radar, N is Nadir (ground below the radar) and G is the location of your furthest slant range pixel that touches the ground. Then RG is called the Line Of Sight (LOS) of the radar. It is also called slant range. The line NG is called ground range. Now, your slant range pixels are equidistantly distributed along the line RG. Projecting them to ground range is nothing else than dropping a perpendicular from their locations on RG to NG. You will notice that those perpendiculars become rather dense in far range. This means than a better (ground range) resolution is achieved in far range compared to those in near range. But in slant range (along RG) all pixels are distributed equidistantly which means that the same resolution is achieved for all pixel along RG.
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