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VEX-T.ASTR-TCN-00349
02
Rev. : 0
06/02/2004
10.15
10.6 STAR TRACKER SOFTWARE
The STR SW runs on its own 32-bit microprocessor (DSP21020) at unit level. Its architecture is
structured in modules according to different operative modes of the sensor (i.e. image acquisition,
image processing, attitude acquisition/determination, and I/O data management).
It is composed of a generic part and a specific part.
The STR SW generic part provides basic services to the AOCMS SW for full visibility and
investigation (health status, auto-tests, programmable window raw video access, memory read and
write).
The STR SW specific part gathers all the tasks related to the application modes and include:
q
Acquisition and Measurement mode: provides three-axis attitude restitution to the AOCMS
SW without initial information from the AOCMS SW (it performs an initial mapping, an
automatic pattern recognition, selects stars and automatically tracks them),
q
Mapping mode: provides magnitude and co-ordinates of all targets present in the field of
view for ground investigation (backup mode),
q
Calibration mode: gives the AOCMS SW the possibility to change default parameters.
The STR SW is a slave to the AOCMS application SW which can always, through equipment TC,
switch off or reset it, change the current mode, modify parameters, dump or patch data and code. In
the same way, the AOCMS SW asks for TM data and is free of reading them, interrupting a
dialogue, asking for other TM data without corrupting the nominal execution of the mission modes.
TM/TC is managed as a high priority task by the STR SW.