diff options
| -rw-r--r-- | core/java/android/hardware/GeomagneticField.java | 138 |
1 files changed, 71 insertions, 67 deletions
diff --git a/core/java/android/hardware/GeomagneticField.java b/core/java/android/hardware/GeomagneticField.java index 0d7b695d7f1d..cbfe4fa58e40 100644 --- a/core/java/android/hardware/GeomagneticField.java +++ b/core/java/android/hardware/GeomagneticField.java @@ -16,7 +16,8 @@ package android.hardware; -import java.util.GregorianCalendar; +import java.util.Calendar; +import java.util.TimeZone; /** * Estimates magnetic field at a given point on @@ -26,7 +27,7 @@ import java.util.GregorianCalendar; * <p>This uses the World Magnetic Model produced by the United States National * Geospatial-Intelligence Agency. More details about the model can be found at * <a href="http://www.ngdc.noaa.gov/geomag/WMM/DoDWMM.shtml">http://www.ngdc.noaa.gov/geomag/WMM/DoDWMM.shtml</a>. - * This class currently uses WMM-2015 which is valid until 2020, but should + * This class currently uses WMM-2020 which is valid until 2025, but should * produce acceptable results for several years after that. Future versions of * Android may use a newer version of the model. */ @@ -48,69 +49,72 @@ public class GeomagneticField { static private final float EARTH_REFERENCE_RADIUS_KM = 6371.2f; // These coefficients and the formulae used below are from: - // NOAA Technical Report: The US/UK World Magnetic Model for 2015-2020 - static private final float[][] G_COEFF = new float[][] { - { 0.0f }, - { -29438.5f, -1501.1f }, - { -2445.3f, 3012.5f, 1676.6f }, - { 1351.1f, -2352.3f, 1225.6f, 581.9f }, - { 907.2f, 813.7f, 120.3f, -335.0f, 70.3f }, - { -232.6f, 360.1f, 192.4f, -141.0f, -157.4f, 4.3f }, - { 69.5f, 67.4f, 72.8f, -129.8f, -29.0f, 13.2f, -70.9f }, - { 81.6f, -76.1f, -6.8f, 51.9f, 15.0f, 9.3f, -2.8f, 6.7f }, - { 24.0f, 8.6f, -16.9f, -3.2f, -20.6f, 13.3f, 11.7f, -16.0f, -2.0f }, - { 5.4f, 8.8f, 3.1f, -3.1f, 0.6f, -13.3f, -0.1f, 8.7f, -9.1f, -10.5f }, - { -1.9f, -6.5f, 0.2f, 0.6f, -0.6f, 1.7f, -0.7f, 2.1f, 2.3f, -1.8f, -3.6f }, - { 3.1f, -1.5f, -2.3f, 2.1f, -0.9f, 0.6f, -0.7f, 0.2f, 1.7f, -0.2f, 0.4f, 3.5f }, - { -2.0f, -0.3f, 0.4f, 1.3f, -0.9f, 0.9f, 0.1f, 0.5f, -0.4f, -0.4f, 0.2f, -0.9f, 0.0f } }; - - static private final float[][] H_COEFF = new float[][] { - { 0.0f }, - { 0.0f, 4796.2f }, - { 0.0f, -2845.6f, -642.0f }, - { 0.0f, -115.3f, 245.0f, -538.3f }, - { 0.0f, 283.4f, -188.6f, 180.9f, -329.5f }, - { 0.0f, 47.4f, 196.9f, -119.4f, 16.1f, 100.1f }, - { 0.0f, -20.7f, 33.2f, 58.8f, -66.5f, 7.3f, 62.5f }, - { 0.0f, -54.1f, -19.4f, 5.6f, 24.4f, 3.3f, -27.5f, -2.3f }, - { 0.0f, 10.2f, -18.1f, 13.2f, -14.6f, 16.2f, 5.7f, -9.1f, 2.2f }, - { 0.0f, -21.6f, 10.8f, 11.7f, -6.8f, -6.9f, 7.8f, 1.0f, -3.9f, 8.5f }, - { 0.0f, 3.3f, -0.3f, 4.6f, 4.4f, -7.9f, -0.6f, -4.1f, -2.8f, -1.1f, -8.7f }, - { 0.0f, -0.1f, 2.1f, -0.7f, -1.1f, 0.7f, -0.2f, -2.1f, -1.5f, -2.5f, -2.0f, -2.3f }, - { 0.0f, -1.0f, 0.5f, 1.8f, -2.2f, 0.3f, 0.7f, -0.1f, 0.3f, 0.2f, -0.9f, -0.2f, 0.7f } }; - - static private final float[][] DELTA_G = new float[][] { - { 0.0f }, - { 10.7f, 17.9f }, - { -8.6f, -3.3f, 2.4f }, - { 3.1f, -6.2f, -0.4f, -10.4f }, - { -0.4f, 0.8f, -9.2f, 4.0f, -4.2f }, - { -0.2f, 0.1f, -1.4f, 0.0f, 1.3f, 3.8f }, - { -0.5f, -0.2f, -0.6f, 2.4f, -1.1f, 0.3f, 1.5f }, - { 0.2f, -0.2f, -0.4f, 1.3f, 0.2f, -0.4f, -0.9f, 0.3f }, - { 0.0f, 0.1f, -0.5f, 0.5f, -0.2f, 0.4f, 0.2f, -0.4f, 0.3f }, - { 0.0f, -0.1f, -0.1f, 0.4f, -0.5f, -0.2f, 0.1f, 0.0f, -0.2f, -0.1f }, - { 0.0f, 0.0f, -0.1f, 0.3f, -0.1f, -0.1f, -0.1f, 0.0f, -0.2f, -0.1f, -0.2f }, - { 0.0f, 0.0f, -0.1f, 0.1f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, -0.1f, -0.1f }, - { 0.1f, 0.0f, 0.0f, 0.1f, -0.1f, 0.0f, 0.1f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f } }; - - static private final float[][] DELTA_H = new float[][] { - { 0.0f }, - { 0.0f, -26.8f }, - { 0.0f, -27.1f, -13.3f }, - { 0.0f, 8.4f, -0.4f, 2.3f }, - { 0.0f, -0.6f, 5.3f, 3.0f, -5.3f }, - { 0.0f, 0.4f, 1.6f, -1.1f, 3.3f, 0.1f }, - { 0.0f, 0.0f, -2.2f, -0.7f, 0.1f, 1.0f, 1.3f }, - { 0.0f, 0.7f, 0.5f, -0.2f, -0.1f, -0.7f, 0.1f, 0.1f }, - { 0.0f, -0.3f, 0.3f, 0.3f, 0.6f, -0.1f, -0.2f, 0.3f, 0.0f }, - { 0.0f, -0.2f, -0.1f, -0.2f, 0.1f, 0.1f, 0.0f, -0.2f, 0.4f, 0.3f }, - { 0.0f, 0.1f, -0.1f, 0.0f, 0.0f, -0.2f, 0.1f, -0.1f, -0.2f, 0.1f, -0.1f }, - { 0.0f, 0.0f, 0.1f, 0.0f, 0.1f, 0.0f, 0.0f, 0.1f, 0.0f, -0.1f, 0.0f, -0.1f }, - { 0.0f, 0.0f, 0.0f, -0.1f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f } }; - - static private final long BASE_TIME = - new GregorianCalendar(2015, 1, 1).getTimeInMillis(); + // NOAA Technical Report: The US/UK World Magnetic Model for 2020-2025 + static private final float[][] G_COEFF = new float[][]{ + {0.0f}, + {-29404.5f, -1450.7f}, + {-2500.0f, 2982.0f, 1676.8f}, + {1363.9f, -2381.0f, 1236.2f, 525.7f}, + {903.1f, 809.4f, 86.2f, -309.4f, 47.9f}, + {-234.4f, 363.1f, 187.8f, -140.7f, -151.2f, 13.7f}, + {65.9f, 65.6f, 73.0f, -121.5f, -36.2f, 13.5f, -64.7f}, + {80.6f, -76.8f, -8.3f, 56.5f, 15.8f, 6.4f, -7.2f, 9.8f}, + {23.6f, 9.8f, -17.5f, -0.4f, -21.1f, 15.3f, 13.7f, -16.5f, -0.3f}, + {5.0f, 8.2f, 2.9f, -1.4f, -1.1f, -13.3f, 1.1f, 8.9f, -9.3f, -11.9f}, + {-1.9f, -6.2f, -0.1f, 1.7f, -0.9f, 0.6f, -0.9f, 1.9f, 1.4f, -2.4f, -3.9f}, + {3.0f, -1.4f, -2.5f, 2.4f, -0.9f, 0.3f, -0.7f, -0.1f, 1.4f, -0.6f, 0.2f, 3.1f}, + {-2.0f, -0.1f, 0.5f, 1.3f, -1.2f, 0.7f, 0.3f, 0.5f, -0.2f, -0.5f, 0.1f, -1.1f, -0.3f}}; + + static private final float[][] H_COEFF = new float[][]{ + {0.0f}, + {0.0f, 4652.9f}, + {0.0f, -2991.6f, -734.8f}, + {0.0f, -82.2f, 241.8f, -542.9f}, + {0.0f, 282.0f, -158.4f, 199.8f, -350.1f}, + {0.0f, 47.7f, 208.4f, -121.3f, 32.2f, 99.1f}, + {0.0f, -19.1f, 25.0f, 52.7f, -64.4f, 9.0f, 68.1f}, + {0.0f, -51.4f, -16.8f, 2.3f, 23.5f, -2.2f, -27.2f, -1.9f}, + {0.0f, 8.4f, -15.3f, 12.8f, -11.8f, 14.9f, 3.6f, -6.9f, 2.8f}, + {0.0f, -23.3f, 11.1f, 9.8f, -5.1f, -6.2f, 7.8f, 0.4f, -1.5f, 9.7f}, + {0.0f, 3.4f, -0.2f, 3.5f, 4.8f, -8.6f, -0.1f, -4.2f, -3.4f, -0.1f, -8.8f}, + {0.0f, 0.0f, 2.6f, -0.5f, -0.4f, 0.6f, -0.2f, -1.7f, -1.6f, -3.0f, -2.0f, -2.6f}, + {0.0f, -1.2f, 0.5f, 1.3f, -1.8f, 0.1f, 0.7f, -0.1f, 0.6f, 0.2f, -0.9f, 0.0f, 0.5f}}; + + static private final float[][] DELTA_G = new float[][]{ + {0.0f}, + {6.7f, 7.7f}, + {-11.5f, -7.1f, -2.2f}, + {2.8f, -6.2f, 3.4f, -12.2f}, + {-1.1f, -1.6f, -6.0f, 5.4f, -5.5f}, + {-0.3f, 0.6f, -0.7f, 0.1f, 1.2f, 1.0f}, + {-0.6f, -0.4f, 0.5f, 1.4f, -1.4f, 0.0f, 0.8f}, + {-0.1f, -0.3f, -0.1f, 0.7f, 0.2f, -0.5f, -0.8f, 1.0f}, + {-0.1f, 0.1f, -0.1f, 0.5f, -0.1f, 0.4f, 0.5f, 0.0f, 0.4f}, + {-0.1f, -0.2f, 0.0f, 0.4f, -0.3f, 0.0f, 0.3f, 0.0f, 0.0f, -0.4f}, + {0.0f, 0.0f, 0.0f, 0.2f, -0.1f, -0.2f, 0.0f, -0.1f, -0.2f, -0.1f, 0.0f}, + {0.0f, -0.1f, 0.0f, 0.0f, 0.0f, -0.1f, 0.0f, 0.0f, -0.1f, -0.1f, -0.1f, -0.1f}, + {0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, -0.1f}}; + + static private final float[][] DELTA_H = new float[][]{ + {0.0f}, + {0.0f, -25.1f}, + {0.0f, -30.2f, -23.9f}, + {0.0f, 5.7f, -1.0f, 1.1f}, + {0.0f, 0.2f, 6.9f, 3.7f, -5.6f}, + {0.0f, 0.1f, 2.5f, -0.9f, 3.0f, 0.5f}, + {0.0f, 0.1f, -1.8f, -1.4f, 0.9f, 0.1f, 1.0f}, + {0.0f, 0.5f, 0.6f, -0.7f, -0.2f, -1.2f, 0.2f, 0.3f}, + {0.0f, -0.3f, 0.7f, -0.2f, 0.5f, -0.3f, -0.5f, 0.4f, 0.1f}, + {0.0f, -0.3f, 0.2f, -0.4f, 0.4f, 0.1f, 0.0f, -0.2f, 0.5f, 0.2f}, + {0.0f, 0.0f, 0.1f, -0.3f, 0.1f, -0.2f, 0.1f, 0.0f, -0.1f, 0.2f, 0.0f}, + {0.0f, 0.0f, 0.1f, 0.0f, 0.2f, 0.0f, 0.0f, 0.1f, 0.0f, -0.1f, 0.0f, 0.0f}, + {0.0f, 0.0f, 0.0f, -0.1f, 0.1f, 0.0f, 0.0f, 0.0f, 0.1f, 0.0f, 0.0f, 0.0f, -0.1f}}; + + static private final long BASE_TIME = new Calendar.Builder() + .setTimeZone(TimeZone.getTimeZone("UTC")) + .setDate(2020, Calendar.JANUARY, 1) + .build() + .getTimeInMillis(); // The ratio between the Gauss-normalized associated Legendre functions and // the Schmid quasi-normalized ones. Compute these once staticly since they @@ -190,7 +194,7 @@ public class GeomagneticField { // We now compute the magnetic field strength given the geocentric // location. The magnetic field is the derivative of the potential // function defined by the model. See NOAA Technical Report: The US/UK - // World Magnetic Model for 2015-2020 for the derivation. + // World Magnetic Model for 2020-2025 for the derivation. float gcX = 0.0f; // Geocentric northwards component. float gcY = 0.0f; // Geocentric eastwards component. float gcZ = 0.0f; // Geocentric downwards component. @@ -203,7 +207,7 @@ public class GeomagneticField { // Negative derivative with respect to latitude, divided by // radius. This looks like the negation of the version in the - // NOAA Techincal report because that report used + // NOAA Technical report because that report used // P_n^m(sin(theta)) and we use P_n^m(cos(90 - theta)), so the // derivative with respect to theta is negated. gcX += relativeRadiusPower[n+2] |