geo2eci: Convert geographic spherical coordinates to Earth-centered...

In astrolibR: Astronomy Users Library

Description

Convert geographic spherical coordinates to Earth-centered inertial coordinates

Usage

geo2eci(incoord, jdtim)

Arguments

incoord	a 3-element vector of geographic coordinates [latitude, longitude, altitude], or an array [3,n] of n such coordinates, in degrees/degrees/km
jdtim	Julian Day time, in days, scalar or vector

Details

Converts from geographic spherical coordinates [latitude, longitude, altitude] to ECI (Earth-Centered Inertial) [X,Y,Z] rectangular coordinates. Geographic coordinates assume the Earth is a perfect sphere, with radius equal to its equatorial radius.

Value

(x, y, z)

a 3-element vector of ECI coordinates, or an array [3,n] of coordinates, in km from Earth center

Author(s)

Written by Pascal Saint-Hilaire (ETH) on 2002/05/14

R adaptation by Arnab Chakraborty June 2013

See Also

ct2lst

Examples

	# Obtain the ECI coordinates of the intersection of the equator and Greenwich's meridian 
	# on 2002/03/09 21:21:21.021
	# Returns: -3902.9606 5044.5548  0.0000
geo2eci(c(0,0,0), 2452343.38982663)  

Example output

[1] -3902.960  5044.555     0.000

astrolibR documentation built on May 2, 2019, 3:26 a.m.