PRISM-19 (PKSR)
Polarimetric K-Band Scanning Radiometer
Project Overview
The
operating frequency of PKSR can be switched between Ku (18.7 GHz
center, 800 MHz bandwidth) and Ka-band (36.5 center, 1.8 GHz
bandwidth), see Figure 2-5. In this study only Kaband will be
used. This radiometer measures brightness temperature at both V
and H polarisations. This horn-shape radiometer can scan from 0°
to 360° with a minimum scan step angle of 0.36°. The maximum scan
speed limit is 120°/sec. The PKSR antennas are made up of a scalar
feed horn at Ka and Ku band and a shared 90˚ metal mirror. The
scalar feed horns were standard off the shelf components with
22.5˚ and 23.5˚ half power beamwidths at Ka and Kuband
respectively. The antenna parameters are tabulated below:
| Parameters | Ka |
Ku |
|---|---|---|
| Mirror Diameter |
8.5" (216 mm) |
|
| Feed 3dB Beam-Width (deg.) |
22.5 |
23.5 |
| Mirror Edge Taper (dB) |
16.1 | 13.6 |
| Feed Beam-Width @ Mirror Edge |
50 |
|
| Feed-Mirror Illumination Efficiency (%) |
96.4 |
94.6 |
| Radiometer 3 dB Beam-Width (deg.) |
3.9 |
7.2 |
| Radiometer 99% BE Beam-Width (deg.) |
10.5 |
19.9 |
Warm
calibration of PKSR was performed before and after each flight by
making brightness temperature measurements of a calibration
target. A long warm and sky calibration was conducted before and
after this campaign. Water calibration was accomplished by
measuring the brightness temperature of a water body (Lake
Wyangan) during each flight.
