Package org.orekit.estimation.measurements

Class Range

  • All Implemented Interfaces:
    Comparable<ComparableMeasurement>, ComparableMeasurement, ObservedMeasurement<Range>, TimeStamped
    public class Range
extends AbstractMeasurement<Range>
    Class modeling a range measurement from a ground station.

    For one-way measurements, a signal is emitted by the satellite and received by the ground station. The measurement value is the elapsed time between emission and reception multiplied by c where c is the speed of light.

    For two-way measurements, the measurement is considered to be a signal emitted from a ground station, reflected on spacecraft, and received on the same ground station. Its value is the elapsed time between emission and reception multiplied by c/2 where c is the speed of light.

    The motion of both the station and the spacecraft during the signal flight time are taken into account. The date of the measurement corresponds to the reception on ground of the emitted or reflected signal.

    The clock offsets of both the ground station and the satellite are taken into account. These offsets correspond to the values that must be subtracted from station (resp. satellite) reading of time to compute the real physical date. These offsets have two effects:

    • as measurement date is evaluated at reception time, the real physical date of the measurement is the observed date to which the receiving ground station clock offset is subtracted
    • as range is evaluated using the total signal time of flight, for one-way measurements the observed range is the real physical signal time of flight to which (Δtg - Δts) ⨉ c is added, where Δtg (resp. Δts) is the clock offset for the receiving ground station (resp. emitting satellite). A similar effect exists in two-way measurements but it is computed as (Δtg - Δtg) ⨉ c / 2 as the same ground station clock is used for initial emission and final reception and therefore it evaluates to zero.

    Since:
    8.0
    Author:
    Thierry Ceolin, Luc Maisonobe, Maxime Journot

    • Constructor Detail

      • Range

        @Deprecated
public Range​(GroundStation station,
             AbsoluteDate date,
             double range,
             double sigma,
             double baseWeight,
             boolean twoWay)
        Deprecated.
        as of 9.3, replaced by Range(GroundStation, boolean, AbsoluteDate, double, double, double, ObservableSatellite)
        Simple constructor.

        This constructor uses 0 as the index of the propagator related to this measurement, thus being well suited for mono-satellite orbit determination.

        Parameters:
        station - ground station from which measurement is performed
        date - date of the measurement
        range - observed value
        sigma - theoretical standard deviation
        baseWeight - base weight
        twoWay - flag indicating whether it is a two-way measurement

      • Range

        @Deprecated
public Range​(GroundStation station,
             boolean twoWay,
             AbsoluteDate date,
             double range,
             double sigma,
             double baseWeight,
             int propagatorIndex)
        Deprecated.
        as of 9.3, replaced by Range(GroundStation, boolean, AbsoluteDate, double, double, double, ObservableSatellite)
        Simple constructor.
        Parameters:
        station - ground station from which measurement is performed
        twoWay - flag indicating whether it is a two-way measurement
        date - date of the measurement
        range - observed value
        sigma - theoretical standard deviation
        baseWeight - base weight
        propagatorIndex - index of the propagator related to this measurement
        Since:
        9.0

      • Range

        public Range​(GroundStation station,
             boolean twoWay,
             AbsoluteDate date,
             double range,
             double sigma,
             double baseWeight,
             ObservableSatellite satellite)
        Simple constructor.
        Parameters:
        station - ground station from which measurement is performed
        twoWay - flag indicating whether it is a two-way measurement
        date - date of the measurement
        range - observed value
        sigma - theoretical standard deviation
        baseWeight - base weight
        satellite - satellite related to this measurement
        Since:
        9.3

    • Method Detail

      • getStation

        public GroundStation getStation()
        Get the ground station from which measurement is performed.
        Returns:
        ground station from which measurement is performed

      • isTwoWay

        public boolean isTwoWay()
        Check if the instance represents a two-way measurement.
        Returns:
        true if the instance represents a two-way measurement