Comparison of QuikSCAT and Oscat
The ISRO Oceansat-2 scatterometer (Oscat) is very similar, but not identical to the SeaWinds scatterometer flown on QuikSCAT. The following detail some of the differences. Note that since some parameters (such as orbit height) vary over the mission life, the values are the nominal reported values for each sensor.
| QuikSCAT | Oscat |
|  |
|
Parameter | | |
Orbit Altitude | 800 km | 720 km |
Orbit Inclination | 98.6 deg | 98.28 deg |
Orbit Asc Node time | 6:00 a.m. +/- 30 min | 12:00 midnight +/- 30 min |
Orbit Period | 101 min | 99.31 min |
Orbits/Day (approx) | 14.25 | 14.5 |
Orbit Repeat Cycle | 4 days | 2 days |
Satellite altitude at equator | 803 km | 720 km |
Frequency | 13.402 GHz | 13.515 GHz |
Wavelength | 2.24 cm | 2.21 cm |
Antenna Spin Rate | 18 rpm | 20.5 rpm |
PRF* | 92.5 Hz | 96.5 Hz |
Mission Data Length | 19 Jun 1999- 23 Nov 2009 | 23 Sep 2009-
|
Inner Beam Polarization | HH | HH |
Inner Beam Incidence Angle | 46 deg | 49 deg |
Inner Beam Slant Range | 1100 km | 1031 km |
Inner Beam Swath Width | 1400 km | 1400 km |
Inner Beam Reported Slices | 8 | 7 |
Inner Beam Beamwidth (Az,El) | 1.6 deg by 1.8 deg | 1.47 deg by 1.62 deg |
Inner Beam Egg Footprint (Az,Rg) | 24.0 km by 31.0 km | 26.8 km by 45.1 km |
Outer Beam Polarization | VV | VV |
Outer Beam Incidence Angle | 54.1 deg | 57 deg |
Outer Beam Slant Range | 1245 km | 1208 km |
Outer Beam Swath Width | 1800 km | 1836 km |
Outer Beam Reported Slices | 8 | 12 |
Outer Beam Beamwidth (Az,Rg) | 1.4 deg by 1.7 deg | 1.39 deg by 1.72 deg |
Outer Beam Egg Footprint (Az, El) | 26.0 km by 36.0 km | 29.7 km by 68.5 km |
* Note that transmit pulses alternate between beams. The Oscat PRF is looked to the spin position while QuikSCAT is free-running.
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