Comparison of SeaWinds/QuikSCAT, OSCAT, and HY-2A
The Indian Space Research Organization (ISRO) Oceansat-2 and SCATsat-1 scatterometers (OSCAT-1/-2) are very similar, but not identical to the SeaWinds scatterometer flown on QuikSCAT and ADEOS-II. The Chinese State Oceanic Administration (SOA) HY-2A is very similar to these as well. The following table details 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.
| SeaWinds | OSCAT | HY-2A |
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Parameter | | | |
Orbit Altitude | 800 km | 720 km | 971 km |
Orbit Inclination | 98.6 deg | 98.28 deg | 99.34 deg |
Orbit Asc Node time | 6:00 a.m. +/- 30 min | 12:00 midnight +/- 30 min | 6:00 p.m. |
Orbit Period | 101 min | 99.31 min | 104.46 min |
Orbits/Day (approx) | 14.25 | 14.5 | 13.78 |
Orbit Repeat Cycle | 4 days | 2 days | 14 & 168 days |
Satellite altitude at equator | 803 km | 720 km | 971 km |
Frequency | 13.402 GHz | 13.515 GHz | 13.256 GHz |
Wavelength | 2.24 cm | 2.21 cm | 2.26 cm |
Antenna Spin Rate | 18 rpm | 20.5 rpm | 18 rpm |
PRF* | 92.5 Hz | 96.5 Hz | 100-200 Hz |
Pulse Length | 1 ms | 1.5 ms | 0.65-1.2 ms |
Nominal Trans Power | 110 W | 120 W | 100 W |
Mission Data Length | QuikSCAT: Jun 1999-Nov 2009** ADEOS-II: Jan 2002-Oct 2002 | OceanSat-2: Sep 2009-Feb 2014 SCATsat-1: Sep 2016- |
Aug 2011-
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Inner Beam Polarization | HH | HH | HH |
Inner Beam Incidence Angle | 46 deg | 49 deg | 41 deg |
Inner Beam Slant Range | 1100 km | 1031 km | |
Inner Beam Swath Width | 1400 km | 1400 km | 1350 km |
Inner Beam Reported Slices | 8 | 7 | N/A |
Inner Beam Beamwidth (Az,El) | 1.6 deg by 1.8 deg | 1.47 deg by 1.62 deg | 1.02 deg by 1.10 deg |
Inner Beam Egg Footprint (Az,Rg) | 24.0 km by 31.0 km | 26.8 km by 45.1 km | 33 km by 26 km |
Outer Beam Polarization | VV | VV | VV |
Outer Beam Incidence Angle | 54.1 deg | 57 deg | 48 deg |
Outer Beam Slant Range | 1245 km | 1208 km | |
Outer Beam Swath Width | 1800 km | 1836 km | 1700 km |
Outer Beam Reported Slices | 8 | 12 | N/A |
Outer Beam Beamwidth (Az,Rg) | 1.4 deg by 1.7 deg | 1.39 deg by 1.72 deg | 1.18 deg by 1.10 deg |
Outer Beam Egg Footprint (Az, El) | 26.0 km by 36.0 km | 29.7 km by 68.5 km | 37 km by 26 km |
* Note that transmit pulses alternate between beams. The Oscat PRF is locked to the spin position while QuikSCAT is free-running.
** QuikSCAT continued operation in non-spinning mode until 2017.
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