LATLONtoITRF: Convert coordinates from geodetic latitude, longitude and...

In asteRisk: Computation of Satellite Position

Convert coordinates from geodetic latitude, longitude and altitude to ITRF

Description

The ITRF (International Terrestrial Reference Frame) is an ECEF (Earth Centered, Earth Fixed) frame of reference, i.e., a non-inertial frame of reference where the origin is placed at the center of mass of Earth, and the frame rotates with respect to the stars to remain fixed with respect to the Earth surface as it rotates. The Z-axis extends along the true North as defined by the IERS reference pole, and the X-axis extends towards the intersection between the equator and the Greenwich meridian at any time. This function converts geodetic latitude, longitude and altitude to Cartesian coordinates in the ITRF frame. The WGS84 Earth ellipsoid model is used.

Usage

LATLONtoITRF(position_LATLON, degreesInput=TRUE)

Arguments

position_LATLON	Vector with the latitude, longitude and altitude of the object. Latitude and longitude can be provided in sexagesimal degrees or in radians (by default, sexagesimal degrees are asumed). Altitude must be provided in meters.
degreesInput	Logical indicating if the input latitude and longitude are in sexagesimal degrees. If degreesInput=FALSE, the input will be considered to be in radians.

Value

A vector with three elements, corresponding to the X, Y and Z components of position in meters in the ITRF frame, in this order.

References

https://apps.dtic.mil/sti/pdfs/ADA280358.pdf

Examples

latitude <- 37.3891
longitude <- -5.9845
altitude <- 20000

# Let´s calculate the corresponding coordinates in ECEF frame

coordinates_ITRF <- LATLONtoITRF(c(latitude, longitude, altitude))

asteRisk documentation built on Jan. 14, 2023, 5:07 p.m.