B. Special Sensor Microwave Imager (SSMI)
The SSMI is a conical-scanning, multi-channel, multi-polarization microwave
radiometer aboard DMSP spacecraft. The SSMI can be seen in figures 2 and
3. Figure 2 shows the sensor by itself, and figure 3 shows where the sensor
is located on the bus (or structure ) of the satellite.
As demonstrated in figure 4, the sensor rotates axially through 360
degrees. However, it only actually scans through 102 degrees of the rotation
in the back of the satellite. This is because of (1) an electronic need
to recalibrate the SSMI every time around, and (2) because of an unavoidable
physical obstruction to the sensors' field of view caused by the bus of
the spacecraft itself. This 102 degree limitation is important because
it cuts down the amount of area the sensor could cover ( SSMI has half
the spatial coverage of the DMSP OLS).
Image provided by Hughes Information Technology Corp. (HITC)
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