GPSScale.java

  1. /* Copyright 2002-2022 CS GROUP
  2.  * Licensed to CS GROUP (CS) under one or more
  3.  * contributor license agreements.  See the NOTICE file distributed with
  4.  * this work for additional information regarding copyright ownership.
  5.  * CS licenses this file to You under the Apache License, Version 2.0
  6.  * (the "License"); you may not use this file except in compliance with
  7.  * the License.  You may obtain a copy of the License at
  8.  *
  9.  *   http://www.apache.org/licenses/LICENSE-2.0
  10.  *
  11.  * Unless required by applicable law or agreed to in writing, software
  12.  * distributed under the License is distributed on an "AS IS" BASIS,
  13.  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14.  * See the License for the specific language governing permissions and
  15.  * limitations under the License.
  16.  */
  17. package org.orekit.time;

  18. import org.hipparchus.CalculusFieldElement;

  19. /** GPS time scale.
  20.  * <p>By convention, TGPS = TAI - 19 s.</p>
  21.  * <p>This is intended to be accessed thanks to {@link TimeScales},
  22.  * so there is no public constructor.</p>
  23.  * @author Luc Maisonobe
  24.  * @see AbsoluteDate
  25.  */
  26. public class GPSScale implements TimeScale {

  27.     /** Serializable UID. */
  28.     private static final long serialVersionUID = 20131209L;

  29.     /** Offset from TAI. */
  30.     private static final double OFFSET = -19;

  31.     /** Package private constructor for the factory.
  32.      */
  33.     GPSScale() {
  34.     }

  35.     /** {@inheritDoc} */
  36.     @Override
  37.     public double offsetFromTAI(final AbsoluteDate date) {
  38.         return OFFSET;
  39.     }

  40.     /** {@inheritDoc} */
  41.     @Override
  42.     public <T extends CalculusFieldElement<T>> T offsetFromTAI(final FieldAbsoluteDate<T> date) {
  43.         return date.getField().getZero().add(OFFSET);
  44.     }

  45.     /** {@inheritDoc} */
  46.     @Override
  47.     public double offsetToTAI(final DateComponents date, final TimeComponents time) {
  48.         return -OFFSET;
  49.     }

  50.     /** {@inheritDoc} */
  51.     public String getName() {
  52.         return "GPS";
  53.     }

  54.     /** {@inheritDoc} */
  55.     public String toString() {
  56.         return getName();
  57.     }

  58. }