AL3A-RM User Guide Version B
Document Number: 451-93156-002B
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XXXXXXX
Where XXXXXXXX is the current Iridium system time available from
the network. The system time as received through the Iridium Air Interface, is a
32 bit integer count of the number of 90 millisecond intervals that have elapsed
since the epoch. The return value is formatted as an ASCII hexadecimal number.
The counter will rollover approximately every 12 years or be changed to prevent
a rollover and as a result should not be used as a time source for user applications.
Iridium system time epoch: March 8, 2007, 03:50:21.00 GMT. (Note: the original
Iridium system time epoch was June 1, 1996, 00:00:11 GMT, and was reset to the
new epoch in January, 2008).
Iridium system time source: The system time is available and valid only after the A3LA-
RM has registered with the network and has received the Iridium system time from
the network. Once the time is received, the A3LA-RM uses its internal clock to
increment the counter. In addition, at least every 8 hours, or on location update or
other event that requires re-registration, the A3LA-RM will obtain a new system time
from the network.
Time localization: None. The system time value is always expressed in GMT time.
Resolution and accuracy: The resolution of the system time is one Iridium frame tick,
or 90 ms. Accuracy as measured by the difference between the time reported and the
actual time this message is sent out of the A3LA-RM’ serial port should not exceed 4
frame ticks (.36 seconds) and in most cases will be one frame tick (.09 seconds) or less.
B.75
–MSGEO
–
R
EQUEST
G
EOLOCATION
Exec Command:
–MSGEO
Query the geolocation grid code received from the network in the last Access Decision
Notification message. The response is of the form:
–MSGEO: <x>,<y>,<z>,<time_stamp>
<x>, <y>, <z> is a geolocation grid code from an earth centered Cartesian coordinate
system, using dimensions, x, y, and z, to specify location. The coordinate system is
aligned such that the z-axis is aligned with the north and south poles, leaving the x-
axis and y-axis to lie in the plane containing the equator. The axes are aligned such
