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