Package org.orekit.estimation.measurements

Class Range

  • All Implemented Interfaces:
    Comparable<ComparableMeasurement>, ComparableMeasurement, ObservedMeasurement<Range>, TimeStamped, ParameterDriversProvider
    public class Range
extends AbstractRangeRelatedMeasurement<Range>
    Class modeling a range measurement received by an observer.

    For one-way measurements, a signal is emitted by the satellite and received by the observer. 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 observer, reflected on spacecraft, and received on the same observer. 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 sensor 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 observer and the satellite are taken into account. These offsets correspond to the values that must be subtracted from sensor (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 observer 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 observer (resp. emitting satellite). A similar effect exists in two-way measurements but it is computed as (Δtg - Δtg) ⨯ c / 2 as the same 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

        public Range​(Observer observer,
             boolean twoWay,
             AbsoluteDate date,
             double range,
             double sigma,
             double baseWeight,
             ObservableSatellite satellite)
        Simple constructor.
        Parameters:
        observer - observer that performs the measurement
        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