COMPONENT MAINTENANCE MANUAL
C17004
34-57-96
Page 21
COPYRIGHT
SEXTANT Avionique 1995
c
(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
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.
(b) Self-test mode
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.
(c) Initialization mode
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.)
MAY 30/95
The document reference is online, please check the correspondence between the online documentation and the printed version.
