ALOS Data Users Handbook

Section 7 Overview of Processing Algorithms1PPS reference pulse1MPPS reference pulseGPSR1PPSreference timeAbsolute navigation dataAttitude dataEphemerisAOCSMissioninstrumentsDMSSpacecraft time1PPS reference pulse1MPPS reference pulsePCD dataFigure 7.1-1 ALOS Time Distribution7.1.2 Coordinates SystemCoordinate systems used by ALOS are shown in the Table below.Table 7.1-1 ALOS Coordinate Systems (1/2)Name of Coordinate Abbr. Origin & Axes DefinitionInternal Coordinate Φ IO I Center of the EarthSystem(J2000.0)X I Direction of true vernal equinoctial point at 0:00 A.M. on Jan. 1stof 2000.Y I Z I x X I directionZ I Direction vertical to true equatorial plane at 0:00 A.M. on Jan. 1stof 2000. (north pole direction is positive)Orbital Reference Φ RO R Ascending nodeCoordinate SystemIt coincides to the orbital coordinate at ascending node.Orbital CoordinateSystemSatellite CoordinateSystemSatellite FixedCoordinate SystemTOD CoordinateSystemΦ OΦ BΦ SΦ TODX RY RR RO OX OY OZ OO BO SX SY SZ SO TODX TODY TODZ TODSatellite BarycenterZ O x X O directionOpposite direction to orbital plane vectorOrigin direction of the inertial coordinateSatellite BarycenterWhen there is no error of attitude,Roll-axisit coincides to the orbitalPitch-axiscoordinate.Yaw-axisIntersection point of the center line and the separation plane thesatellite separation partIt is parallel to each axis of the Satellite barycentric coordinate.Center of the EarthDirection of the current truevernal equinoctial pointZ TOD x X TODDirection vertical to thepresent true equatorial plane(north pole direction ispositive)Current inertial coordinate systemtaking account of precession andnutation of the Earth for Φ I7-2