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Comparison of QuikSCAT, Oscat, and HY-2A

The Indian Space Research Organization (ISRO) Oceansat-2 scatterometer (Oscat) is very similar, but not identical to the SeaWinds scatterometer flown on QuikSCAT. The Chinese State Oceanic Administration (SOA) HY-2A is very similar to these, too. 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.

 QuikSCAT Oscat HY-2A
Orbit Altitude 800 km 720 km971 km
Orbit Inclination 98.6 deg 98.28 deg99.34 deg
Orbit Asc Node time 6:00 a.m. +/- 30 min 12:00 midnight +/- 30 min6:00 p.m.
Orbit Period 101 min 99.31 min104.46 min
Orbits/Day (approx) 14.25 14.5 13.78
Orbit Repeat Cycle 4 days 2 days14 & 168 days
Satellite altitude at equator 803 km 720 km971 km
Frequency 13.402 GHz 13.515 GHz13.256 GHz
Wavelength 2.24 cm 2.21 cm2.26 cm
Antenna Spin Rate 18 rpm 20.5 rpm18 rpm
PRF* 92.5 Hz 96.5 Hz100-200 Hz
Pulse Length 1 ms 1.5 ms0.65-1.2 ms
Nominal Trans Power 110 W 120 W100 W
Mission Data Length 19 Jun 1999-
23 Nov 2009**
23 Sep 2009-Feb 2014
Aug 2011-
Inner Beam Polarization HH HH HH
Inner Beam Incidence Angle 46 deg 49 deg41 deg
Inner Beam Slant Range 1100 km 1031 km 
Inner Beam Swath Width 1400 km 1400 km1350 km
Inner Beam Reported Slices 8 7N/A
Inner Beam Beamwidth (Az,El) 1.6 deg by 1.8 deg 1.47 deg by 1.62 deg1.02 deg by 1.10 deg
Inner Beam Egg Footprint (Az,Rg) 24.0 km by 31.0 km 26.8 km by 45.1 km33 km by 26 km
Outer Beam Polarization VV VVVV
Outer Beam Incidence Angle 54.1 deg 57 deg48 deg
Outer Beam Slant Range 1245 km 1208 km 
Outer Beam Swath Width 1800 km 1836 km1700 km
Outer Beam Reported Slices 8 12N/A
Outer Beam Beamwidth (Az,Rg) 1.4 deg by 1.7 deg 1.39 deg by 1.72 deg1.18 deg by 1.10 deg
Outer Beam Egg Footprint (Az, El) 26.0 km by 36.0 km 29.7 km by 68.5 km37 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 continues operation in non-spinning mode.