Examples with GPSAlmanac org.orekit.gnss.GPSAlmanac used on opensource projects

Example 1 with GPSAlmanac

use of org.orekit.gnss.GPSAlmanac in project Orekit by CS-SI.

the class DOPComputation method run.

private void run(final OneAxisEllipsoid shape, final List<GeodeticPoint> zone, final double meshSize, final double minElevation, final AbsoluteDate tStart, final AbsoluteDate tStop, final double tStep) throws IOException, OrekitException, ParseException {
    // Gets the GPS almanacs from the SEM file
    final SEMParser reader = new SEMParser(null);
    reader.loadData();
    final List<GPSAlmanac> almanacs = reader.getAlmanacs();
    // Creates the GPS propagators from the almanacs
    final List<Propagator> propagators = new ArrayList<Propagator>();
    for (GPSAlmanac almanac : almanacs) {
        // Only keeps almanac with health status ok
        if (almanac.getHealth() == 0) {
            propagators.add(new GPSPropagator.Builder(almanac).build());
        } else {
            System.out.println("GPS PRN " + almanac.getPRN() + " is not OK (Health status = " + almanac.getHealth() + ").");
        }
    }
    // Meshes the area of interest into a grid of geodetic points.
    final List<List<GeodeticPoint>> points = sample(shape, zone, meshSize);
    // Creates the DOP computers for all the locations of the sampled geographic zone
    final List<DOPComputer> computers = new ArrayList<DOPComputer>();
    for (List<GeodeticPoint> row : points) {
        for (GeodeticPoint point : row) {
            computers.add(DOPComputer.create(shape, point).withMinElevation(minElevation));
        }
    }
    // Computes the DOP for each point over the period
    final List<List<DOP>> allDop = new ArrayList<List<DOP>>();
    // Loops on the period
    AbsoluteDate tc = tStart;
    while (tc.compareTo(tStop) != 1) {
        // Loops on the grid points
        final List<DOP> dopAtDate = new ArrayList<DOP>();
        for (DOPComputer computer : computers) {
            try {
                final DOP dop = computer.compute(tc, propagators);
                dopAtDate.add(dop);
            } catch (OrekitException oe) {
                System.out.println(oe.getLocalizedMessage());
            }
        }
        allDop.add(dopAtDate);
        tc = tc.shiftedBy(tStep);
    }
    // Post-processing: gets the statistics of PDOP over the zone at each time
    System.out.println("                           PDOP");
    System.out.println("          Date           min  max");
    for (List<DOP> dopAtDate : allDop) {
        final StreamingStatistics pDoP = new StreamingStatistics();
        for (DOP dopAtLoc : dopAtDate) {
            pDoP.addValue(dopAtLoc.getPdop());
        }
        final AbsoluteDate date = dopAtDate.get(0).getDate();
        System.out.format(Locale.ENGLISH, "%s %.2f %.2f%n", date.toString(), pDoP.getMin(), pDoP.getMax());
    }
}

Example 2 with GPSAlmanac

use of org.orekit.gnss.GPSAlmanac in project Orekit by CS-SI.

the class GPSPropagatorTest method testTLE.

@Test
public void testTLE() throws OrekitException {
    List<GPSPropagator> gpsPropagators = new ArrayList<GPSPropagator>();
    for (final GPSAlmanac almanac : almanacs) {
        gpsPropagators.add(new GPSPropagator.Builder(almanac).build());
    }
    // the following map corresponds to the GPS constellation status in early 2016
    final Map<Integer, TLE> prnToTLE = new HashMap<Integer, TLE>();
    prnToTLE.put(1, new TLE("1 37753U 11036A   16059.51505483 -.00000016  00000-0  00000+0 0  9995", "2 37753  55.2230 119.7200 0049958  23.9363 306.3749  2.00566105 33828"));
    prnToTLE.put(2, new TLE("1 28474U 04045A   16059.68518942 -.00000018 +00000-0 +00000-0 0  9992", "2 28474 054.0048 117.2153 0156693 236.8152 092.4773 02.00556694082981"));
    prnToTLE.put(3, new TLE("1 40294U 14068A   16059.64183862 +.00000012 +00000-0 +00000-0 0  9990", "2 40294 054.9632 179.3690 0003634 223.4011 136.5596 02.00553679009768"));
    prnToTLE.put(4, new TLE("1 34661U 09014A   16059.51658765 -.00000072  00000-0  00000+0 0  9997", "2 34661  56.3471   0.6400 0080177  48.0430 129.2467  2.00572451 50844"));
    prnToTLE.put(5, new TLE("1 35752U 09043A   16059.39819238  .00000011  00000-0  00000+0 0  9993", "2 35752  54.2243 178.7652 0044753  24.8598  29.4422  2.00555538 47893"));
    prnToTLE.put(6, new TLE("1 39741U 14026A   16059.18044747 -.00000016  00000-0  00000+0 0  9990", "2 39741  55.2140 119.2493 0005660 259.2190 100.7882  2.00566982 13061"));
    prnToTLE.put(7, new TLE("1 32711U 08012A   16059.36304856 -.00000033 +00000-0 +00000-0 0  9998", "2 32711 055.4269 300.7399 0091867 207.6311 151.9340 02.00564257058321"));
    prnToTLE.put(8, new TLE("1 40730U 15033A   16059.44106931 -.00000026 +00000-0 +00000-0 0  9994", "2 40730 055.1388 059.0069 0020452 282.1769 077.6168 02.00566073004562"));
    prnToTLE.put(9, new TLE("1 40105U 14045A   16059.27451329  .00000045  00000-0  00000+0 0  9996", "2 40105  54.7529 238.9873 0004485 121.4766 238.5557  2.00568637 11512"));
    prnToTLE.put(10, new TLE("1 41019U 15062A   16059.49433942  .00000013  00000-0  00000+0 0  9991", "2 41019  54.9785 179.1399 0012328 204.9013 155.0292  2.00561967  2382"));
    prnToTLE.put(11, new TLE("1 25933U 99055A   16059.51073770 -.00000024  00000-0  00000+0 0  9997", "2 25933  51.3239  98.4815 0159812  86.1576 266.7718  2.00565163120122"));
    prnToTLE.put(12, new TLE("1 29601U 06052A   16059.62966898 -.00000070 +00000-0 +00000-0 0  9994", "2 29601 056.7445 002.2755 0057667 037.0706 323.3313 02.00552237067968"));
    prnToTLE.put(13, new TLE("1 24876U 97035A   16059.41696335  .00000046  00000-0  00000+0 0  9998", "2 24876  55.6966 245.8203 0044339 114.8899 245.5712  2.00562657136305"));
    prnToTLE.put(14, new TLE("1 26605U 00071A   16059.56211888  .00000047  00000-0  00000+0 0  9997", "2 26605  55.2663 243.7251 0085518 248.7231  95.5323  2.00557009112094"));
    prnToTLE.put(15, new TLE("1 32260U 07047A   16059.45678257 +.00000044 +00000-0 +00000-0 0  9994", "2 32260 053.3641 236.0940 0079746 026.4105 333.9774 02.00547771061402"));
    prnToTLE.put(16, new TLE("1 27663U 03005A   16059.14440417 -.00000071  00000-0  00000+0 0  9996", "2 27663  56.7743   3.3691 0085346  17.6322 214.4333  2.00559487 95843"));
    prnToTLE.put(17, new TLE("1 28874U 05038A   16059.21070933 -.00000024  00000-0  00000+0 0  9997", "2 28874  55.8916  61.9596 0112077 248.9647 205.7384  2.00567116 76379"));
    prnToTLE.put(18, new TLE("1 26690U 01004A   16059.51332910  .00000008  00000-0  00000+0 0  9990", "2 26690  52.9999 177.6630 0169501 250.8579 153.6293  2.00563995110499"));
    prnToTLE.put(19, new TLE("1 28190U 04009A   16058.12363503 -.00000030  00000-0  00000+0 0  9999", "2 28190  55.7230  64.8110 0105865  40.0254 321.4519  2.00572212 87500"));
    prnToTLE.put(20, new TLE("1 26360U 00025A   16059.44770263  .00000005  00000-0  00000+0 0  9992", "2 26360  53.0712 174.6895 0046205  76.0615 334.4302  2.00559931115818"));
    prnToTLE.put(21, new TLE("1 27704U 03010A   16059.50719524 -.00000019  00000-0  00000+0 0  9998", "2 27704  53.6134 117.9454 0234081 255.6874 199.2128  2.00564673 94659"));
    prnToTLE.put(22, new TLE("1 28129U 03058A   16059.06680941  .00000008  00000-0  00000+0 0  9990", "2 28129  52.8771 177.7253 0079127 245.1376 114.0279  2.00398763 89357"));
    prnToTLE.put(23, new TLE("1 28361U 04023A   16059.54310021  .00000046  00000-0  00000+0 0  9995", "2 28361  54.2347 239.3240 0106509 211.5355  11.7648  2.00557932 85613"));
    prnToTLE.put(24, new TLE("1 38833U 12053A   16059.04618549 -.00000032  00000-0  00000+0 0  9999", "2 38833  54.4591 298.1383 0042253  18.7074 341.5041  2.00568407 24895"));
    prnToTLE.put(25, new TLE("1 36585U 10022A   16059.29300735 -.00000074  00000-0  00000+0 0  9993", "2 36585  56.0738 359.4320 0050768  38.3425  49.1794  2.00578535 42134"));
    prnToTLE.put(26, new TLE("1 40534U 15013A   16059.28299301 -.00000076  00000-0  00000+0 0  9994", "2 40534  55.0430 359.0082 0009349 342.4081  17.5685  2.00558853  6801"));
    prnToTLE.put(27, new TLE("1 39166U 13023A   16059.40401153 -.00000025  00000-0  00000+0 0  9990", "2 39166  55.6020  59.1224 0032420   7.7969 352.2759  2.00568484 20414"));
    prnToTLE.put(28, new TLE("1 26407U 00040A   16059.80383354 -.00000069 +00000-0 +00000-0 0  9994", "2 26407 056.6988 003.6328 0201499 267.0948 317.6209 02.00569902114508"));
    prnToTLE.put(29, new TLE("1 32384U 07062A   16059.44770263 -.00000021  00000-0  00000+0 0  9992", "2 32384  55.9456  62.5022 0011922 319.9531 172.6730  2.00571577 60128"));
    prnToTLE.put(30, new TLE("1 39533U 14008A   16059.40267873 -.00000038 +00000-0 +00000-0 0  9996", "2 39533 054.6126 303.3404 0017140 179.4267 180.6311 02.00568364014251"));
    prnToTLE.put(31, new TLE("1 29486U 06042A   16059.50651990 -.00000032  00000-0  00000+0 0  9992", "2 29486  55.7041 301.2472 0084115 334.2804 254.9897  2.00560606 69098"));
    prnToTLE.put(32, new TLE("1 41328U 16007A   16059.56873502  .00000049  00000-0  00000+0 0  9991", "2 41328  55.0137 239.0304 0002157 298.9074  61.0768  1.99172830   453"));
    for (final GPSPropagator gpsPropagator : gpsPropagators) {
        final int prn = gpsPropagator.getGPSOrbitalElements().getPRN();
        TLE tle = prnToTLE.get(prn);
        TLEPropagator tlePropagator = TLEPropagator.selectExtrapolator(tle);
        for (double dt = 0; dt < Constants.JULIAN_DAY; dt += 600) {
            final AbsoluteDate date = tlePropagator.getInitialState().getDate().shiftedBy(dt);
            final PVCoordinates gpsPV = gpsPropagator.getPVCoordinates(date, gpsPropagator.getECI());
            final PVCoordinates tlePV = tlePropagator.getPVCoordinates(date, gpsPropagator.getECI());
            Assert.assertEquals(0.0, Vector3D.distance(gpsPV.getPosition(), tlePV.getPosition()), 8400.0);
        }
    }
}

Example 3 with GPSAlmanac

use of org.orekit.gnss.GPSAlmanac in project Orekit by CS-SI.

the class GPSPropagatorTest method testDerivativesConsistency.

@Test
public void testDerivativesConsistency() throws OrekitException {
    final Frame eme2000 = FramesFactory.getEME2000();
    double errorP = 0;
    double errorV = 0;
    double errorA = 0;
    for (final GPSAlmanac almanac : almanacs) {
        GPSPropagator propagator = new GPSPropagator.Builder(almanac).build();
        GPSOrbitalElements elements = propagator.getGPSOrbitalElements();
        AbsoluteDate t0 = AbsoluteDate.createGPSDate(elements.getWeek(), 0.001 * elements.getTime());
        for (double dt = 0; dt < Constants.JULIAN_DAY; dt += 600) {
            final AbsoluteDate central = t0.shiftedBy(dt);
            final PVCoordinates pv = propagator.getPVCoordinates(central, eme2000);
            final double h = 10.0;
            List<TimeStampedPVCoordinates> sample = new ArrayList<TimeStampedPVCoordinates>();
            for (int i = -3; i <= 3; ++i) {
                sample.add(propagator.getPVCoordinates(central.shiftedBy(i * h), eme2000));
            }
            final PVCoordinates interpolated = TimeStampedPVCoordinates.interpolate(central, CartesianDerivativesFilter.USE_P, sample);
            errorP = FastMath.max(errorP, Vector3D.distance(pv.getPosition(), interpolated.getPosition()));
            errorV = FastMath.max(errorV, Vector3D.distance(pv.getVelocity(), interpolated.getVelocity()));
            errorA = FastMath.max(errorA, Vector3D.distance(pv.getAcceleration(), interpolated.getAcceleration()));
        }
    }
    Assert.assertEquals(0.0, errorP, 3.8e-9);
    Assert.assertEquals(0.0, errorV, 3.5e-8);
    Assert.assertEquals(0.0, errorA, 1.1e-8);
}