Sag: Glonass Almanac Data - Magellan ProFlex 500 Reference Manual

Data Output

SAG: GLONASS Almanac Data

284
Type Name Size
Unsigned Check-
2
short sum
Total 70
This message contains almanac data for one GLONASS
satellite.
The message is as follows:
$PASHR,SAG,<structure>
The message's binary structure is described in the table
below.
Type Name
Short prn
Short frq
Short health
Float e
Long
Float
Float w0
Float
w Float
Float Af0
Float Af1
Float
Unsigned short checksum 2
Total
Contents
The checksum is computed by breaking the
structure into 34 unsigned shorts, adding them
together, and taking the least significant 16 bits
of the result.
Size Contents
2 Satellite number 1-24
Satellite GLONASS frequency number
2
[-7,...,6]
2 Satellite health 0=bad, 1=good
4 Eccentricity
Reference day number (days in range 1 to
4
1461)
4 Correction to inclination (semicircles)
Longitude of first ascending node (semicir-
4
cles)
Reference time of longitude of first node
4
(seconds)
4 Argument of perigee (semicircles)
Correction to mean value (43200 s) of
4
Draconic period
4 Af1=d(Af0)/dt(sec/sec)
4 Satellite clock offset (seconds)
The checksum is computed by breaking
the structure into 21 unsigned shorts, add-
ing them together, and taking the least sig-
nificant 16 bits of the result.
44