ObservableSatellite.java
- /* Copyright 2002-2022 CS GROUP
- * Licensed to CS GROUP (CS) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * CS licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- package org.orekit.estimation.measurements;
- import org.hipparchus.util.FastMath;
- import org.orekit.utils.ParameterDriver;
- /** Class modeling a satellite that can be observed.
- *
- * @author Luc Maisonobe
- * @since 9.3
- */
- public class ObservableSatellite {
- /** Prefix for clock offset parameter driver, the propagator index will be appended to it. */
- public static final String CLOCK_OFFSET_PREFIX = "clock-offset-satellite-";
- /** Prefix for clock drift parameter driver, the propagator index will be appended to it. */
- public static final String CLOCK_DRIFT_PREFIX = "clock-drift-satellite-";
- /** Clock offset scaling factor.
- * <p>
- * We use a power of 2 to avoid numeric noise introduction
- * in the multiplications/divisions sequences.
- * </p>
- */
- private static final double CLOCK_OFFSET_SCALE = FastMath.scalb(1.0, -10);
- /** Index of the propagator related to this satellite. */
- private final int propagatorIndex;
- /** Parameter driver for satellite clock offset. */
- private final ParameterDriver clockOffsetDriver;
- /** Parameter driver for satellite clock drift. */
- private final ParameterDriver clockDriftDriver;
- /** Simple constructor.
- * @param propagatorIndex index of the propagator related to this satellite
- */
- public ObservableSatellite(final int propagatorIndex) {
- this.propagatorIndex = propagatorIndex;
- this.clockOffsetDriver = new ParameterDriver(CLOCK_OFFSET_PREFIX + propagatorIndex,
- 0.0, CLOCK_OFFSET_SCALE,
- Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY);
- this.clockDriftDriver = new ParameterDriver(CLOCK_DRIFT_PREFIX + propagatorIndex,
- 0.0, CLOCK_OFFSET_SCALE,
- Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY);
- }
- /** Get the index of the propagator related to this satellite.
- * @return index of the propagator related to this satellite
- */
- public int getPropagatorIndex() {
- return propagatorIndex;
- }
- /** Get the clock offset parameter driver.
- * <p>
- * The offset value is defined as the value in seconds that must be <em>subtracted</em> from
- * the satellite clock reading of time to compute the real physical date. The offset
- * is therefore negative if the satellite clock is slow and positive if it is fast.
- * </p>
- * @return clock offset parameter driver
- */
- public ParameterDriver getClockOffsetDriver() {
- return clockOffsetDriver;
- }
- /** Get the clock drift parameter driver.
- * <p>
- * The drift is negative if the satellite clock is slowing down and positive if it is speeding up.
- * </p>
- * @return clock offset parameter driver
- * @since 10.3
- */
- public ParameterDriver getClockDriftDriver() {
- return clockDriftDriver;
- }
- }