Satellite Resolution

Satellite resolution considers:

• Spatial resolution: the size of the spots (pixels) that can be resolved. Spatial resolution is usually give as the side length of each pixel. For each pixel there will be one value of the energy reflected or emitted in each band. Smaller (better) resolution means more pixels, but less energy per pixel. Improving the spatial resolution by going to pixels half as big on a side will result in four times the number of pixels.  With smaller pixels the swath width will be smaller, and the revisit time for the satellite will be longer.  The smaller swath width, if the satellite only images at nadir, reduces the geometric distortions which increase if either the swath width is wide, or the sensor looks to the side.
• Spectral resolution: the range of wavelengths imaged. This goes with the number of bands or channels; the smaller the size of each band, the less energy available but the better the estimate of the color of light being imaged.
• Radiometric resolution: the accuracy with which the reflected or emitted energy can be measured. For visual images this does not have to be great, but for accurate measurement of things like temperature the radiometric resolution must be very good and able to resolve small differences in energy detected.
• Temporal resolution: how often the location will be revisited. Getting high temporal resolution (frequent coverage) requires large swath widths and severe geometric distortion at the edges of coverage. This is a function of orbital mechanics, and angular field of view, and whether the sensor can be aimed away from nadir.

Last revision 5/31/2020