Gpredict User Manual
the pass and not will include it in the list of passes.
Number of passes to predict
This parameter defines how many passes gpredict should try to find when
looking for future passes.
Passes should occur within
This parameter sets the time limit within which the predicted passes should
occur. When the time variable in the prediction algorithm reaches this time
limit gpredict will stop looking for passes even if it has not found the
number of passes requested in the previous parameter.
These two parameter should therefore be thought of as “either or”, i.e.
gpredict will either stop when it has found X number of passes or when it
reaches the time limit – whichever comes first.
Time resolution
When showing the details of a given pass gpredict will try to reach the time
resolution specified with this parameter. This resolution should be thought
of as a lower limit – the number of entries (next option) in the detailed pass
prediction window will have precedence over this condition.
Number of entries
This parameter defines the number of entries gpredict should display in the
detailed pass prediction window. The exact number might deviate from this
but it will always be around this number.
Twilight threshold
This parameter has influence on when gpredict considers a satellite to be
visible. Theoretically, a satellite can be visible if it is in sunlight but the
ground station is in darkness. The problem is that darkness in this respect
is not an absolute entity and this parameter defines the threshold for the
elevation of the Sun at which the ground station is considered to be in
darkness.
Following definitions exist for twilight:
Civil twilight
0° to -6°
Nautical twilight
-6° to -12°
Astronomical twilight
-12° to -18°
For most uses the “civil darkness” will be adequate.
Always use real time for pass predictions
If you check this option Gpredict will always use the current system time as
starting point for future pass predictions, even when you are running in
simulation mode. If you leave the box unchecked Gpredict will take the
time from the time controller to predict future passes from.
5.1.2 Multiple Passes
The check-boxes on this page allows you to select what data gpredict
should show when listing multiple passes. You can choose between:
●
Acquisition of signal (AOS) – the time when the satellite comes
within range.
●
Time of closest approach (TCA) – the time when the elevation of the
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