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Let's take as an example the Sentinel-1 SAR satellite for which data is accessible online.
The pixel spacing in the range and in the azimuth are found inside the xml files bundled with the product. But I need the resolution instead.

For a level-1 SLC product, the spacings are given as:

<rangePixelSpacing>2.329562e+00</rangePixelSpacing>
<azimuthPixelSpacing>1.396573e+01</azimuthPixelSpacing>

But, how do I calculate the resolution based on the knowledge of thePixel Spacing?

  • It's a rectangular pixel, not square, so there are two resolution values: 2.3 by 13.9. – mkennedy Aug 26 '15 at 17:36
  • @mkennedy you mean that the resolution = pixel spacing? (I know that the resolution is not the same in the range and in the azimuth, that's why there are two pixel spacing values). – Hakim Aug 26 '15 at 17:48
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    Have a look here: SAR Sentinel-1 resolutions – Nir Aug 27 '15 at 1:53
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    Not entirely sure, perhaps this will help you understand. – Nir Aug 27 '15 at 13:37
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    Thanks for the link. I understood that the pixel spacing is different from the resolution although they're related. Besides, the pixel spacing is also related the sampling rate. – Hakim Aug 27 '15 at 22:41
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Based on my own understanding:

In SAR images resolution and pixel spacing are two different things.

Resolution means the maximum ability to distinguish two close scatters. The resolution of one SAR image is usually based on the bandwidth of signal (in Range direction) and the 'synthetic bandwidth' in azimuth direction.

Well Pixel spacing is easier, it just means in your SAR image, what does one pixel correspond to meters in real world.

Pixel spacing usually does not equal to resolution. It is usually slightly bigger. This is because the images we can get are usually resampled again before they are delivered to you.

So you don't calculate resolution based on pixel spacing, you calculate them based on other parameters such as bandwidth and etc.

1

The ground range resolution = ((pixel spacing in range)/sin(incidence angle))

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