----+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
OFFSET 7806401 0. 1.331 0.896 4.789
----+----0----+----0----+----0----+----0----+----0----+----0----+----0----+----0
COLUMNS FORMAT DESCRIPTION DEFAULT VALUE & UNITS
1-6 A6 OFFSET - Inputs body-centered
coordinates for antenna offset
or laser reflector offset.
7 I1 = 1 Indicates link 1 of offset. 0
A second link (OFFSET2) must follow.
= 2 Indicates link 2 of offset.
[NOTE 1], [NOTE 2]
= 7 Antenna orientation vector
in the x direction
= 8 Antenna orientation vector
in the y direction
= 9 Antenna orientation vector
in the z direction
[NOTE 6], [NOTE 7]
8 I1 = 9 Indicates external attitude model 0
used for link # 1 rotations and
link # 2 movable antenna rotations. Must
have external attitude file available.
If this option is selected an antenna # in
column 17 must be present, only antenna
#'s 1-4 are valid.
This option overrides the coordinate
system specified in column 15.
Not applicable for OFFSET2 card.
OFFSET1 card value is used for OFFSET2.
[NOTE 2]
9 I1 = 1 Indicates use of new metric data format 0
prepro word antenna idenfication scheme.
If this option is selected an antenna # in
column 17 must be present, only antenna
#'s 1-4 are valid.
Not applicable for OFFSET2 card.
OFFSET1 card value is used for OFFSET2.
[NOTE 3]
SEP 2002
0209.0
GLOBAL SET
OFFSET (cont)
COLUMNS FORMAT DESCRIPTION DEFAULT VALUE & UNITS
11-12 I2 Antenna type number used for phase map corrections
14-15 I2 Body fixed coordinate system 0
used to calculate offset. [NOTE 4]
0 - Position and velocity vectors
1 - Position and sun vectors
2 - TOPEX/Poseidon
3 - SPOT-2
4 - GPS
5 - ERS-1
6 - Mars observer Mapping Phase
7 - Mars observer Cruise Phase
8 - TDRSS
9 - Magnetically stabilized S/C
10 - GFO
11 - TRMM
12 - EUVE
13 - VCL
Not applicable for OFFSET2 card.
OFFSET1 card value is used for OFFSET2.
16-17 I2 Antenna number (optional if frequency
is specified). Mandatory if external attitude
or new metric data antenna identification
scheme is selected. This antenna number must
match the appropriate external attitude file
antenna number and/or the metric data antenna
number.
Not applicable for OFFSET2 card.
OFFSET1 card value is used for OFFSET2.
OR
50+ Laser Id if Laser Altimeter data are being
processed. If the laser Altimeter Id is 1 then
the user should put 51 on columns 16-17. This
convention distinguishes from the antenna number
and the antenna identification scheme in the
GEODYN code.
SEP 2002
0209.0
GLOBAL SET
OFFSET (cont)
COLUMNS FORMAT DESCRIPTION DEFAULT VALUE & UNITS
18-24 I7 Satellite ID (required). 0
Not applicable for OFFSET2 card.
OFFSET1 card value is used for OFFSET2.
25-44 D20.8 Frequency in mega-hertz. Used to 0. MH
discriminate between antennae when
more than one antenna is on a satellite.
( Frequency = 0. implies that offset
applies to all antenna.)
Not applicable for OFFSET2 card.
OFFSET1 card value is used for OFFSET2.
(optional if antenna number and
new prepro ID scheme selected).
If the index in column 7 is equal to 7
then this field contains the first component
of the orientation unit vector in the x direction
If the index in column 7 is equal to 8
then this field contains the first component
of the orientation unit vector in the y direction
If the index in column 7 is equal to 9
then this field contains the first component
of the orientation unit vector in the z direction
45-59 D15.3 Body centered fixed offset link 1 or 0. M
link 2 antenna from center of figure; x-axis.
If the index in column 7 is equal to 7
then this field contains the second component
of the orientation unit vector in the x direction
If the index in column 7 is equal to 8
then this field contains the second component
of the orientation unit vector in the y direction
If the index in column 7 is equal to 9
then this field contains the second component
of the orientation unit vector in the z direction
SEP 2002
0209.0
GLOBAL SET
OFFSET (cont)
60-72 D13.1 Body centered fixed offset link 1 or 0. M
link 2 antenna from center of figure; y-axis.
If the index in column 7 is equal to 7
then this field contains the third component
of the orientation unit vector in the x direction
If the index in column 7 is equal to 8
then this field contains the third component
of the orientation unit vector in the y direction
If the index in column 7 is equal to 9
then this field contains the third component
of the orientation unit vector in the z direction
73-80 D8.3 Body centered fixed offset link 1 or 0. M
link 2 antenna from center of figure; z-axis.
OR Antenna Cutoff angle if the index on col. 7
is "9"
NOTE [1] : OFFSET1 and OFFSET2 cards are a pair. OFFSET1 card must be
followed by OFFSET2 card.
NOTE [2] : See Volume 5 for a description of the external attitude file.
Multiple link offset may only be used with Mars observer
(Col 15 = 6) and external attitude. Using multiple links implies
link # 1 is Spacecraft Body Fixed (SBF) Frame, and link # 2 is a
movable link. Link 1 and CGMASS vector are in the same SBF frame
Link # 2 gets rotaton from external attitude or internal attitude
model. If q1 of quaternions equals -9999999 for any point in the
block, then the internal model (selected in col. 15) will be used
for the offset vector rotations. If no SBF to J2000 quaternions
are found for the antenna number requested then the internal model
(selected in col. 15) will be used for the offset vector rotations.
If no movable antenna quaternions are present in the external
attitude file only the 1st link will be applied with the SBF to
J2000 quaternion information.
NOTE [3] : See the antenna identification word in the metric data format
description.
SEP 2002
0209.0
GLOBAL SET
OFFSET (cont)
NOTE [4] : The two vectors listed for each group are the initial vectors used
to describe the satellite body fixed coordinate system.
(options 0 and 1 only)
Position and velocity vectors - The X-axis is given by the velocity
vector, the X-axis crossed with the position vector gives the
Y-axis, and the X-axis crossed with the Y-axis gives the Z-axis.
Position and sun vectors - The Z-axis is given by the negative of
the position vector, the Z-axis crossed with the sun vector gives
the Y-axis, and the Y-axis crossed with the Z-axis gives the X-axis.
NOTE [5] : See CGMASS for reference between center of figure/center of gravity.
NOTE [6] : The default values for the antenna orientation vectors
for GPS satellites
x = (1,0,0)
y = (0,1,0)
z = (0,0,1)
for user satellites
x = (1,0,0)
y = (0,-1,0)
z = (0,0,-1)
NOTE [7] : If the index in column 7 is 7, 8 or 9
then the user needs to fill the satellite ID (cols 18-24)
and the first 3 real fields with the antenna orientation
in all 3 directions.
UNITS: KM =Kilometers; M =Meters ; S =Seconds ; M/S=Meters per second
H =Hertz ; MH =Mega-Hertz;
IF CARD OMITTED: No antenna offset will be applied.
