Document title: Readme.doc for DE-2 coordinate transformation matrices, for
NDADS VEFIMAGB datatype
Project: DE
NDADS Datatype: VEFIMAGB
Super-EID: DOCUMENT
There may be other documents also identified by this super-EID.
NDADS filename: VEFIMAGB_AVG_MATRIX_README.DOC
TRF entry B46571.txt in NSSDC's controlled digital document library. Feb. 1998.
Document text follows:
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Dynamics Explorer (DE)-2 Matrix Files
The DE-2 matrix files contain the elements of the 3 by 3 transformation
matrix used to convert from Spacecraft to Topographic Coordinates.
The matrix values are provided at 5 second intervals and each file covers
the existing data for an entire day. ( Use interpolation to obtain 0.5sec
resolution data).
File names use a year, month, day of month format, so that
81_10_27.MAT contains matrix values for October 27, 1981. Each record of
a file contains the time in seconds and the 9 matrix values written with
a format statement of 1X,I5,9F10.6. The matrix values are written in column
order. If T(i,j) is the matrix element from row i and column j, then the
matrix values are written in the following order:
T(1,1) T(2,1) T(3,1) T(1,2) T(2,2) T(3,2) T(1,3) T(2,3) T(3,3).
The Topographic coordinate system is defined for Earth surface:
the X axis points to the North,
the Y axis points to the East, and
the Z axis points to the center of the Earth.
If X', Y' Z' - axis in SPC coordinate system, then coordinate transformation
to X, Y, Z is given by:
|X| |T(1,1) T(1,2) T(1,3)| |X'|
|Y| = |T(2,1) T(2,2) T(2,3)| |Y'|
|Z| |T(3,1) T(3,2) T(3,3)| |Z'|
and
X=X'*T(1,1)+ Y'*T(1,2) +Z'*T(1,3)
Y=X'*T(2,1)+ Y'*T(2,2) +Z'*T(2,3)
Z=X'*T(3,1)+ Y'*T(3,2) +Z'*T(3,3)