LLA2ecf

MATLAB

G = LLA2ecf(Glla)
[R, V] = LLA2ecf(Rlla,[Vlla],[EarthModel])

Description

Converts coordinate frame from a latitude, longitude, altitude (LLA), speed, heading description to earth-centered fixed (ECF), in which the coordinate frame is fixed to the rotating earth.

Parameters

Parameters	Description
Glla [struct/list]	Geometry parameters. Can be a structure (or array of structures) from GeomStruct or a comma separated list of (Rlla,[Vlla],[EarthModel])
Rlla [Nx3 matrix]	N 3-element LLA position vectors [Lat Long Alt]. Lat is the Latitude in degrees (-90 to 90), Long is the longitude positions in degrees (-180 to 180), and Alt is the altitude (m).
Vlla [Nx3 matrix]	(Optional) N 3-element LLA velocity vectors ([Vxy Heading Vz]). Vxy is the velocity in a cylindrical coordinate frame with the XY plane tangent to the Earth's surface (m/s). Heading is the heading in degrees clockwise (from North). Vz is the velocity in the vertical direction (m/s).
EarthModel [string/numeric]	(Optional) If string, Geometric (default) or Geodetic. Use Geometric for a spherical earth and Geodetic for an oblate earth. If numeric and scalar - spherical Earth radius, if vector - [a b], where a is the equatorial radius and b is the polar radius. Must pass in Vlla (can be []) to specify earth model.

Return Values

Return Values	Description
G [struct]	If Glla is a structure, G will be a structure with position and velocity vectors in ECF coordinates. Otherwise, the output will be position and [velocity] vectors [R, [V]].
R [Nx3 matrix]	ECF position vectors (m)
V [Nx3 matrix]	ECF velocity vectors (m/s)

Examples

>> Glla = struct('Coordinates','LLA','RP',[0.25 0 1000], ...

'RT',[0 0 10],'VP',[100 90 0],'VT',[10 0 0], ...

'EarthRadius',PhysicalConst('remean'));

>> Gecf = LLA2ecf(Glla);

Convert a geometry structure in LLA coordinates to ECF

>> R = LLA2ecf([10 0 1000])

Convert an LLA position vector to ECF

>> [R V] = LLA2ecf([10 0 1000], [100 90 0], 'geodetic')

Convert LLA position and velocity assuming geodetic earth model