iSXblue/SXBlue II GNSS Series Technical Reference Manual
133
Table 6-10 Bin 98 Message
Group
Components
Type
Bytes
Value
AlmanData
Almanac-derived-data, 8 satellites
at a time
Structure
array
8 x 8 =64
See the following
table
LastAlman
Last almanac processed
Byte
1
0 to 31
IonoUTCVFlag
Flag that is set when ionosphere
modeling data is extracted from
the GPS sub frame 4
Byte
1
0 = not logged
2 = valid
Spare
Not used at this time
Unsigned
short
2
Future use
AlmanData Structure Array
Group
Components
Type
Bytes
Value
DoppHz
Predicted Doppler in Hz for the
satellite in question (assuming a
stationary satellite).
Short
2
CountUpdate
Number of times the almanac has
changed for this satellite since the
receiver was turned on
Byte
1
Positive
Svindex
Channel number (groups of 8)
Byte
1
0 to 7
8 to 15
16 to 23
24 to 31
AlmVFlag
Almanac valid flag
Byte
1
0 = not logged
1 = invalid
2 = valid
3 = has data
(not yet validated)
AlmHealth
Almanac health from sub frame 4
of the GPS message
Byte
1
See ICD-GPS-200
Elev
Elevation angle in degrees
Char
1
-90 to 90
Azimuth
½ the azimuth in degrees
Byte
1
0 to 180 represents
360 degrees
6.1.10
Bin 99
This message has a BlockID of 99 and is 304 bytes excluding the header and epilogue. This message
contains quantities related to the tracking of the individual GPS satellites along with some other relevant
data. The following table describes the constituents of this message in order.