Earth

Earth

Earth provides basic properties for gravity, size/shape, rotation, and standard sea level air characteristics.

Static Methods

static double ACCEL_OF_GRAVITY()

Returns the acceleration due to gravity at earth’s surface (9.80665 m/s^2).

Note

This value is defined by the ISO-80000-3 standard, not the result of a specific measurement.

static double GRAVITATIONAL_PARAMETER()

Returns Earth’s gravitational parameter (3.986005e+14 m^3/s^2).

Note

This value is defined in the WGS-84 standard.

static double SSL_AIR_DENSITY()

Returns the density of air at standard sea level conditions (1.2250 kg / m^3).

static double MASS()

Returns the Earth’s mass (5.9736e+24 kg).

static double EQUATORIAL_RADIUS()

Returns the Earth’s equatorial radius (6378137.0 m).

Note

This value is defined in the WGS-84 standard.

static double POLAR_RADIUS()

Returns the Earth’s polar radius (6356752.3142 m).

Note

This value is defined in the WGS-84 standard.

static double MEAN_RADIUS()

Returns the Earth’s mean (spherical) radius (6371000.0 m).

Note

This value is the volumetric mean radius, or radius at which the volume of the ellipsoid is the same as the spherical volume.

static double ROTATION_RATE()

Returns the Earth’s rotation rate (4.178074622245e-3 deg / s).

static double GEOSTATIONARY_RADIUS()

Return the radius of a geostationary orbit for the Earth (4.216416963417e+07 m).

static bool LineOfSight(Vec3 aLocationECI_1, Vec3 aLocationECI_2)

Returns whether the ECI locations’ line-of-sight with one another is blocked by the Earth.

static Vec3 SubSolarPoint(Calendar aEpoch)

Returns the WCS position of the sub-solar point at the given aEpoch.

static Vec3 SubLunarPoint(Calendar aEpoch)

Returns the WCS position of the sub-lunar point at the given aEpoch.

static double CATE_Angle(Vec3 aObserverECI, Vec3 aTargetECI)

Returns the CAmera-Target-Earth (CATE) angle in degrees. The CATE angle is the angle between the line segment from the given target ECI location, aTargetECI, to the given observer ECI location, aObserverECI, and the line segment from aTargetECI to the Earth.

static Vec3 ConvertECI_ToWCS(Calendar aEpoch, Vec3 aLocationECI)

Convert the given The Earth Centered Inertial System (ECI) aLocationECI at the given aEpoch to the equivalent position in the The World Coordinate System (WCS) frame.

Warning

This method is computationally intensive, and may impact simulation run time.

static Vec3 ConvertWCS_ToECI(Calendar aEpoch, Vec3 aLocationWCS)

Convert the given The World Coordinate System (WCS) aLocationWCS at the given aEpoch to the equivalent position in the The Earth Centered Inertial System (ECI) frame.

Warning

This method is computationally intensive, and may impact simulation run time.