Navigation Coordinate Frame Conversions

Converts between navigational coordinate frames

Description

Coordinate frame conversions including
ECEF 2 ECI
ECI 2 ECEF
ECEF 2 ENU
ENU 2 ECEF
Earth Centered Earth Fixed
Earth Centered Inertial
East North Up (Ownship)

Should be helpful for navigation applications.

• MATLAB release: MATLAB 7.4 (R2007a)

[harry balzer]

Error undefined function or variable libpointer
on line 14 ecef to enu

[Javier Areta]

The code is given in a DLL, which from my point of view is a big minus. It would be much more useful (at least from an understanding what's going on point of view) to have it as a script. Perhaps the library call is faster, but it does not help me. Also, some comments on the code would be useful.

[Jason Chiou]

The way it converts velocity from ECI to ECEF is wrong. You don't use the same rotation matrix, used for converting position, to convert the velocity.
Here is what's in and what's out.

>> eci.x = 1;
eci.y = 1;
eci.z = 1;
eci.xdot =10;
eci.ydot = 10;
eci.zdot = 10;

dt =540;

ecef = ECI2ECEF( eci, dt)

ecef =

x: 1.0386
y: 0.9599
z: 1
xdot: 10.3867
ydot: 9.5993
zdot: 10

Obviously, the velocity out is wrong.
Take a look at the following page:
http://www.constell.org/Downloads/Manual-Version70.pdf