Measurement Concept
The SMAP observatory includes a dedicated spacecraft and instrument suite that will be launched into a near-polar, sun-synchronous orbit on an expendable launch vehicle.
The SMAP measurement system consists of a radiometer (passive) instrument and a synthetic aperture radar (active) instrument operating with multiple polarizations in the L-band range (1.20-1.41 GHz).
The active and passive sensors provide coincident measurements of the surface emission and backscatter. The instruments sense conditions in the top 5 cm of soil through moderate vegetation cover to yield globally mapped estimates of soil moisture and its freeze-thaw state. The combined active and passive measurement approach takes advantage of the spatial resolution of the radar and the sensing accuracy of the radiometer.
Read more about this topic: Soil Moisture Active Passive
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