The Advanced Very High Resolution Radiometer (AVHRR) is a multi-purpose
imaging instrument used for global measurement of cloud cover, sea surface
temperature, ice, snow and vegetation cover and characteristics. This
instrument is currently flying on the NOAA series of spacecraft in a
five channel version (no channel 3a present). AVHRR has 6 channels in
the visible and infra-red between 0.63 and 12.0 micrometers, with an
instantaneous footprint of 1.1 km at the sub-satellite point. The internal
rotating scan mirror also views deep space and a thermal calibration
source on each rotation. Scanning is cross-track with a range of ±55.37
about nadir.
Calibration of the IR channels is performed with 4
internal black bodies every scan line. The calibration
coefficients for the visible channels are determined
pre launch.
AVHRR scans across track of the satellite path in
continuous scan. There are 2048 Earth Views per scan
over a swath of ±1447 km. The squared instantaneous
field of view has a size of 1.1 km at nadir. |