NavCom Sapphire Rev.J - Manual (Page 88)

Sapphire Technical Reference Manual Rev. J
88
The datum can be provided by the system (built-in datum), or it can be defined by a
user, in which case the user supplies all parameters in the specific format from the
command line.
Command: [DATUM] [DATUM_SELECTION] DEFAULT, GDA94, USERDATUM
Parameter Definition
DEFAULT
Default datum of the system (ITRF2008, ITRF2005 or WGS84_G1150); no
[PARAMETER_LIST] fields
WGS84
Transform StarFire ITRF2005 (v2.0.22.0 to v2.2.9; and v3.0.9.0 and later when in StarFire
GPS mode) or ITRF2008 (v3.0.9.0 or later for StarFire GNSS mode) datum to WGS84
G1150.
No [PARAMETER_LIST] fields required.
GDA94 Geocentric datum of Australia (1994); no [PARAMETER_LIST] fields
USERDATUM
User-defined datum – the user provides the parameters in predefined format,
[PAR AMETER1], …,[PARAMETER17] See Note 1, below.

1 Only one user datum can be stored at one time. Entering a new user datum
overwrites that which is currently stored.
Command:
[DATUM] [PARAMETER_LIST] (the parameter list for user-defined datum – see
)
The parameters contain the following types of information and determine the type of
transformation model to be used:
1. Ellipsoid model
2. 3-parameter model
3. 7-parameter model
4. 14-parameter model
Table 57: Parameter List for User-Defined Datum
Overall
Sequence #
Value Data Type Valid Range Remarks
Keyword USERDATUM Text String
1 Semi-major axis (meters)
double*
* double =
decimal number
(R64 data type)
6377137
to 6379137
Ellipsoid Model
2 Inverse-flat integer -9999 to 9999
3 Source datum reference year double 1980 to 9999
4 Translation in x (meters) double -1000 to 1000 Used in 3,7,14
parameter
transformation
5 Translation in y (meters) double -1000 to 1000
6 Translation in z (meters) double -1000 to 1000