001 package edu.nrao.sss.astronomy;
002
003 import java.math.BigDecimal;
004 import java.util.Calendar;
005 import java.util.Date;
006 import java.util.Random;
007
008 import edu.nrao.sss.math.Polynomial;
009 import edu.nrao.sss.math.PolynomialTerm;
010 import edu.nrao.sss.measure.AngularVelocityUnits;
011 import edu.nrao.sss.measure.ArcUnits;
012 import edu.nrao.sss.measure.Distance;
013 import edu.nrao.sss.measure.DistanceUnits;
014 import edu.nrao.sss.measure.Latitude;
015 import edu.nrao.sss.measure.Longitude;
016 import edu.nrao.sss.measure.TimeInterval;
017 import edu.nrao.sss.util.EnumerationUtility;
018
019 /**
020 * Helper for test classes; builds sky positions with randomized data.
021 * <p>
022 * <b>Version Info:</b>
023 * <table style="margin-left:2em">
024 * <tr><td>$Revision$</td></tr>
025 * <tr><td>$Date$</td></tr>
026 * <tr><td>$Author$</td></tr>
027 * </table></p>
028 *
029 * @author David M. Harland
030 * @since 2007-04-19
031 */
032 public class SkyPositionBuilder
033 {
034 private static final EnumerationUtility ENUM_UTIL =
035 EnumerationUtility.getSharedInstance();
036
037 private static final String INFO_ORIGIN = "SkyPositionBuilder.java";
038
039 private Random random = new Random(System.currentTimeMillis());
040
041 private EphemerisTableBuilder ephemBuilder = new EphemerisTableBuilder();
042
043 //Used for coordinating multiple intervals
044 private Date timeIntervalEnd = null;
045
046 //============================================================================
047 //
048 //============================================================================
049
050 public SkyPosition makePosition()
051 {
052 SkyPosition position;
053
054 double posType = random.nextDouble();
055
056 if (posType < 0.20) position = makeSimplePosition();
057 else if (posType < 0.40) position = makePolynomialPosition();
058 else if (posType < 0.60) position = makePolynomialTable();
059 else if (posType < 0.80) position = makeEphemerisTable();
060 else if (posType < 0.90) position = makeOrbit();
061 else position = makeSolarSystemPosition();
062
063 return position;
064 }
065
066 public SimpleSkyPosition makeSimplePosition()
067 {
068 SimpleSkyPosition position = new SimpleSkyPosition();
069
070 position.setCoordinateSystem(ENUM_UTIL.getRandomValueFor(CelestialCoordinateSystem.class));
071 position.setEpoch(random.nextDouble() < 0.2 ? Epoch.B1950 : Epoch.J2000);
072 position.setOriginOfInformation(INFO_ORIGIN);
073
074 Longitude longitude = makeLongitude();
075 Latitude latitude = makeLatitude();
076 Distance distance = makeBigDistance();
077
078 position.getLongitude().set(longitude.getValue(), longitude.getUnits());
079 position.getLatitude().set( latitude.getValue(), latitude.getUnits());
080 position.getDistance().set( distance.getValue(), distance.getUnits());
081
082 BigDecimal error = BigDecimal.valueOf(random.nextDouble() * 1e-4);
083
084 position.getLongitudeUncertainty().set(longitude.getValue().multiply(error),
085 longitude.getUnits());
086
087 error = BigDecimal.valueOf(random.nextDouble() * 1e-4);
088
089 position.getLatitudeUncertainty().set(latitude.getValue().multiply(error),
090 latitude.getUnits());
091
092 error = BigDecimal.valueOf(random.nextDouble() * 1e-4);
093
094 position.getDistanceUncertainty().set(error.multiply(distance.getValue()),
095 distance.getUnits());
096
097 return position;
098 }
099
100 public EphemerisTable makeEphemerisTable()
101 {
102 return ephemBuilder.makeTable();
103 }
104
105 public Orbit makeOrbit()
106 {
107 Orbit orbit = new Orbit();
108
109 orbit.setOriginOfInformation(INFO_ORIGIN);
110
111 orbit.setArgumentOfPeriapsis(360.0 * random.nextDouble());
112 orbit.setEccentricity(0.5 * random.nextDouble());
113 orbit.setInclination(45.0 * random.nextDouble());
114 orbit.setMeanAnomaly(360.0 * random.nextDouble());
115 orbit.setRightAscensionAscendingNode(
116 new Longitude(Double.toString(360.0 * random.nextDouble())));
117 orbit.setSemiMajorAxis(0.1 + 49.9 * random.nextDouble());
118
119 return orbit;
120 }
121
122 public PolynomialPositionTable makePolynomialTable()
123 {
124 return makePolynomialTable(false);
125 }
126
127 public PolynomialPositionTable makePolynomialTable(boolean wellFormed)
128 {
129 PolynomialPositionTable table = new PolynomialPositionTable();
130
131 int size = 3 + random.nextInt(17);
132
133 for (int p=0; p < size; p++)
134 {
135 table.add(makePolynomialPosition());
136
137 if (!wellFormed)
138 timeIntervalEnd = null;
139 }
140
141 timeIntervalEnd = null;
142
143 return table;
144 }
145
146 public PolynomialPosition makePolynomialPosition()
147 {
148 return makePolynomialPosition(new PolynomialPosition());
149 }
150
151 private PolynomialPosition makePolynomialPosition(PolynomialPosition pp)
152 {
153 pp.setValidTime(makeTimeInterval(timeIntervalEnd));
154 pp.setReferenceTime(pp.getValidTime().getStart());
155 pp.setEpoch(random.nextDouble() < 0.2 ? Epoch.B1950 : Epoch.J2000);
156 pp.setOriginOfInformation(INFO_ORIGIN);
157 pp.setLatitudeAtTimeZero(new Latitude(Double.toString(-90.0 + 180.0 * random.nextDouble())));
158 pp.setLongitudeAtTimeZero(new Longitude(Double.toString(360.0 * random.nextDouble())));
159 Polynomial eqn = new Polynomial();
160 eqn.add(new PolynomialTerm(-100.0 + 200.0 * random.nextDouble(), 1));
161 pp.setRadialMotion(eqn);
162
163 //0, 1, or 2 motion terms
164 double d0;
165 int count = random.nextInt(3);
166 if (count < 1.0) //very far away sources
167 {
168 d0 = 100.0 + 10000.0 * random.nextDouble();
169 pp.setDistanceAtTimeZero(new Distance(BigDecimal.valueOf(d0),
170 DistanceUnits.LIGHT_YEAR));
171 }
172 else if (count < 2.0) //far away sources
173 {
174 d0 = 5.0 + 100.0 * random.nextDouble();
175 pp.setDistanceAtTimeZero(new Distance(BigDecimal.valueOf(d0),
176 DistanceUnits.LIGHT_YEAR));
177
178 pp.setLatitudeVelocityUnits(AngularVelocityUnits.MILLI_ARC_SECONDS_PER_YEAR);
179 eqn = new Polynomial();
180 eqn.add(new PolynomialTerm(-500.0 + 1000.0 * random.nextDouble(), 1));
181 pp.setLatitudeMotion(eqn);
182
183 pp.setLongitudeVelocityUnits(AngularVelocityUnits.MILLI_ARC_SECONDS_PER_YEAR);
184 eqn = new Polynomial();
185 eqn.add(new PolynomialTerm(-500.0 + 1000.0 * random.nextDouble(), 1));
186 pp.setLongitudeMotion(eqn);
187 }
188 else //nearby sources
189 {
190 d0 = 3.0 + 97.0 * random.nextDouble();
191 pp.setDistanceAtTimeZero(new Distance(BigDecimal.valueOf(d0),
192 DistanceUnits.ASTRONOMICAL_UNIT));
193
194 pp.setLatitudeVelocityUnits(AngularVelocityUnits.ARC_SECONDS_PER_DAY);
195 eqn = new Polynomial();
196 eqn.add(new PolynomialTerm(-50.0 + 100.0 * random.nextDouble(), 1));
197 eqn.add(new PolynomialTerm(-5.0 + 10.0 * random.nextDouble(), 2));
198 pp.setLatitudeMotion(eqn);
199
200 pp.setLongitudeVelocityUnits(AngularVelocityUnits.ARC_SECONDS_PER_DAY);
201 eqn = new Polynomial();
202 eqn.add(new PolynomialTerm(-50.0 + 100.0 * random.nextDouble(), 1));
203 eqn.add(new PolynomialTerm(-5.0 + 10.0 * random.nextDouble(), 2));
204 pp.setLongitudeMotion(eqn);
205 }
206
207 return pp;
208 }
209
210 private static final String[] BODIES =
211 {
212 "Mercury", "Venus", "Mars", "Ceres", "Vesta", "Jupiter", "Saturn",
213 "Uranus", "Neptune", "Pluto", "Ida"
214 };
215
216 public SolarSystemBodyPosition makeSolarSystemPosition()
217 {
218 SolarSystemBodyPosition position =
219 new SolarSystemBodyPosition(BODIES[random.nextInt(BODIES.length)]);
220
221 //TODO more random stuff
222
223 return position;
224 }
225
226 //============================================================================
227 // HELPERS
228 //============================================================================
229
230 private TimeInterval makeTimeInterval(Date startTime)
231 {
232 int year, month, day;
233 Date from;
234 Calendar cal = Calendar.getInstance();
235
236 if (startTime == null)
237 {
238 year = 1950 + random.nextInt(55);
239 month = random.nextInt(12);
240 day = 1 + random.nextInt(27);
241 cal.set(year, month, day);
242
243 from = cal.getTime();
244 }
245 else
246 {
247 cal.setTime(startTime);
248
249 from = startTime;
250 }
251
252 cal.add(Calendar.DATE, random.nextInt(3000));
253 cal.add(Calendar.SECOND, random.nextInt(24*60*60));
254
255 timeIntervalEnd = cal.getTime();
256
257 return new TimeInterval(from, timeIntervalEnd);
258 }
259
260 private Longitude makeLongitude()
261 {
262 ArcUnits units = ENUM_UTIL.getRandomValueFor(ArcUnits.class);
263
264 BigDecimal value = units.toFullCircle().multiply(new BigDecimal(random.nextDouble()));
265
266 return new Longitude(value, units);
267 }
268
269 private Latitude makeLatitude()
270 {
271 ArcUnits units = ENUM_UTIL.getRandomValueFor(ArcUnits.class);
272
273 BigDecimal value = units.toQuarterCircle().multiply(new BigDecimal(random.nextDouble()));
274
275 if (random.nextDouble() < 0.5)
276 value = value.negate();
277
278 return new Latitude(value, units);
279 }
280
281 private Distance makeBigDistance()
282 {
283 DistanceUnits units = null;
284 switch(random.nextInt(3))
285 {
286 case 0: units = DistanceUnits.KILOMETER; break;
287 case 1: units = DistanceUnits.ASTRONOMICAL_UNIT; break;
288 case 2: units = DistanceUnits.LIGHT_YEAR; break;
289 }
290
291 BigDecimal au = BigDecimal.valueOf(random.nextInt(1000000) + 1);
292 BigDecimal value = DistanceUnits.ASTRONOMICAL_UNIT.toUnits(units).multiply(au);
293
294 return new Distance(value, units);
295 }
296 }