Thales NSS 100S-1 Component Maintenance Manual With Illustrated Parts List page 43

(3) Operating modes
The RPU has various operating modes, the procedure and sequencing of
which are defined by the software program, according to the state of the
RPU, the number of satellites received, the presence (or absence) and
the state of certain parameters. The various modes of operation are:
- Stop
- Self test
- Initialization
- Clock warm-up
- Sky Reac
- DR
- Position-fixing.
(a) Stop mode
(b) Self-test mode
(c) Initialization mode
COPYRIGHT SEXTANT Avionique 1995
c
The document reference is online, please check the correspondence between the online documentation and the printed version.
COMPONENT MAINTENANCE MANUAL
In this mode, the RPU is not powered by the aircraft mains; nonethe-
less it performs all of the following processing operations, using
two batteries:
- Time maintenance (real-time clock),
- Storage of the existing almanacs and ephemerides in the protected
memory area before the RPU power is turned off,
- Storage of the last position calculated.
As soon as the power is turned on, the RPU performs self-test se-
quences on each of its subassemblies.
Once these self-tests have been completed, the RPU goes to the next
mode.
Note: Cyclic self-tests are then carried out as background tasks in
all operating modes.
This mode enables use of all accessible data necessary for acquiring
the satellite states.
The RPU takes into account:
- Any parameters that may have been stored: position, almanac, time
maintained (provided their validity has been verified),
- A certain number of environmental parameters (aircraft dynamics,
speed aid quality, etc.)
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