Maretron GPS100 - Manual (Page 22)

GPS100 User’s Manual
Page A6 Appendix A – NMEA 2000 ® Interfacing Revision 1.2
default for this field is 0 (do not use the antenna altitude; rather, use the altitude
calculated when the GPS100 was most recently in 3D mode).
PGN 129541 – GPS Almanac Data
The GPS100 uses this PGN to provide a single transmission that contains relevant almanac
data for the GPS. The almanac contains satellite vehicle course orbital parameters. This
information is not considered precise and is only valid for several months at a time. GPS100
receive almanac data directly from the satellites. GPS100 sends this PGN only when
requested by PGN 059904 (ISO Request).
Field 1: PRN – PRN of the satellite for which almanac data is being provided.
2: GPS Week Number – The number of weeks since Jan 6, 1980.
3: SV Health Bits – Bits 17-24 of each almanac page. Refer to ICD-GPS-200
paragraph 20.3.3.5.1.3, Table 20-VII and Table 20-VIII.
4: Eccentricity – Reference ICD-GPS-200 Table 20-VI.
5: Almanac Reference Time – Reference ICD-GPS-200 Table 20-VI.
6: Inclination Angle – Reference ICD-GPS-200 Table 20-VI.
7: Rate of Right Ascension – The OMEGADOT parameter. Reference ICD-GPS-200
Table 20-VI.
8: Root of Semi-major Axis – Reference ICD-GPS-200 Table 20-VI.
9: Argument of Perigee – Reference ICD-GPS-200 Table 20-VI.
10: Longitude of Ascension Mode – Reference ICD-GPS-200 Table 20-VI.
11: Mean Anomaly – Reference ICD-GPS-200 Table 20-VI.
12: Clock Parameter 1 – Reference ICD-GPS-200 Table 20-VI.
13: Clock Parameter 2 – Reference ICD-GPS-200 Table 20-VI.
14: Reserved (2 bits) – This field is reserved by NMEA; therefore, this field always
contains a value of 0x3 (the GPS100 sets all bits to a logic 1)
GPS100 NMEA 2000 ® Received PGNs
PGN 126208 – NMEA Command Group Function – GNSS Control Status
This will change the configuration of the GPS100.
Field 1: Complex Command Group Function Code (8 bits) – set this field’s value to 0x01,
which denotes a command PGN.
2: Commanded PGN (24 bits) – set this field’s value to 129538, which denotes the
GNSS Control Status PGN.
3: Priority Setting (4 bits) – set this field’s value to 0x8, which indicates to leave priority
settings unchanged.
4: Reserved (4 bits) – set this field’s value to 0xF, which is the value for a reserved field
of this size.
5: Number of Pairs of Commanded Parameters to Follow (8 bits) – set this field’s value
to the number of configurations to be changed.
6: Field number of first commanded parameter (8 bits). Please refer to the table below
for valid values for this field.
7: Value of first command parameter (size depends on the field number specified in
field 6 of this PGN) – please refer to the description of PGN 129538 above for
details.