Class GroundStation

  • public class GroundStation
    extends Object
    Class modeling a ground station that can perform some measurements.

    This class adds a position offset parameter to a base topocentric frame.

    Since 9.0, this class also adds parameters for an additional polar motion and an additional prime meridian orientation. Since these parameters will have the same name for all ground stations, they will be managed consistently and allow to estimate Earth orientation precisely (this is needed for precise orbit determination). The polar motion and prime meridian orientation will be applied after regular Earth orientation parameters, so the value of the estimated parameters will be correction to EOP, they will not be the complete EOP values by themselves. Basically, this means that for Earth, the following transforms are applied in order, between inertial frame and ground station frame (for non-Earth based ground stations, different precession nutation models and associated planet oritentation parameters would be applied, if available):

    Since 9.3, this class also adds a station clock offset parameter, which manages the value that must be subtracted from the observed measurement date to get the real physical date at which the measurement was performed (i.e. the offset is negative if the ground station clock is slow and positive if it is fast).

    1. precession/nutation, as theoretical model plus celestial pole EOP parameters
    2. body rotation, as theoretical model plus prime meridian EOP parameters
    3. polar motion, which is only from EOP parameters (no theoretical models)
    4. additional body rotation, controlled by getPrimeMeridianOffsetDriver() and getPrimeMeridianDriftDriver()
    5. additional polar motion, controlled by getPolarOffsetXDriver(), getPolarDriftXDriver(), getPolarOffsetYDriver() and getPolarDriftYDriver()
    6. station clock offset, controlled by getClockOffsetDriver()
    7. station position offset, controlled by getEastOffsetDriver(), getNorthOffsetDriver() and getZenithOffsetDriver()
    Luc Maisonobe