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Topcon HiPer GD and HiPer GGD Operator’s Manual
2-40
Collecting Almanacs
Each satellite broadcasts a message (almanac) which gives the
approximate orbit for itself and all other satellites. If the receiver
has an almanac, you can considerably reduce the time needed to
search for and lock on to satellite signals.
The receiver regularly updates the almanac and stores the most
recent almanac in its Non-Volatile Random Access Memory
(NVRAM).
1. Set up the receiver (connect the external antenna if needed) in a
location with a clear view of the sky.
2. Turn on the receiver. Wait for about 15 minutes while the
receiver collects almanac data from satellites.
NOTICE
NOTICE
If 15 minutes have passed and the receiver does not lock
on to satellites, you may need to clear the NVRAM. See
“Clearing the NVRAM” on page 4-18 for this procedure.
You will need to collect or update the almanac:
• If the receiver has been off for a long time.
• If the last known receiver position, stored in the NVRAM, is
different from the present position by several hundred
kilometers.
• After loading a new OAF.
• After loading new firmware.
• After clearing the NVRAM.
• Before surveying.
The collection and/or update of an almanac can take as long as 15
minutes.
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