Memory reset
The contents of the tracking memory must be erased when the ACU starts to track a new
satellite. This is done in the following situations:
A stored position (target) is recalled.
The ACU is switched off.
'CLEAR MEMORY' is chosen at the
tracking parameters
page.
If a new antenna position is entered by setting the azimuth / elevation angles explicitly, the ACU
does not know the new position is a manually optimized one for the current satellite or the
position of another satellite. The tracking memory is not erased in this situation. If the new
position belongs to a new satellite, the tracking memory must be erased manually by clicking to
'CLEAR MEMORY' at the
tracking parameters
page. Beside this it is recommended to perform a
'CLEAR MEMORY' about half an hour after tracking a satellite starts the first time. This erases the
first search steps to the satellite's position and significantly improves the quality of the first
adaptive model which will be calculated 6 hours later.
Saving the memory contents
The ACU provides one persistent memory location where the tracking memory may by saved into
on an operators request. This may be useful to track another satellite for a couple of hours and
then to return to the first satellite. If the tracking memory has been saved before the antenna has
been moved to the second satellite, it may be restored after the antenna returned to the old
position.
To use this feature, store the ACU settings to the target location 0 (
Target memory page
). This
saves the tracking parameters and the tracking memory as well. When this memory location is
recalled later on, the parameters and the memory contents are restored. With this function you
should keep in mind, that the tracking memory contents becomes useless after about 24 hours.
8.4.3 Adaptive Tracking Parameters
The behaviour of the adaptive is adjustable with a couple of parameters. First, adaptive tracking
also is a step track algorithm. The parameters described in chapter
'8.3.4 Steptrack Parameters'
therefore apply to the adaptive tracking as well. The parameters concerning the adaptive tracking
in particular are discussed in the table below. All parameter described here are to be set at the
Tracking
page.
AZMaximummodeltype ELMaximummodeltype --- These settings let you limit the
adaptive model to a simpler one, the ACU would choose by itself. The maximum model type
can be set individually for each axis. Normally you will set both axes to 'LARGE', which
leaves the model selection fully to the ACU's internal selection algorithms.In cases where the
ACU seems to be too 'optimistic' about the quality of the step track results, the maximum
model on one or both axes may be limited to a more simple and more noise-resistant model.
Specially inclined orbit satellites which are located close to the longitude of the antenna's
geodetic location may require this limitation for the azimuth axis. With such a satellite, the
elevation may move several degrees while the azimuth shows almost no motion.
Levelthreshold --- If the beacon level falls below this threshold value, the ACU does not
perform a step track cycle. If the level falls below the threshold during the steptrack cycle,
the cycle gets aborted.If the ADAPTIVE tracking is enabled and there is enough data in the
tracking memory, the ACU computes a mathematical model from the stored data and predicts
the antenna pointing position from the extrapolation of the model. If the tracking mode is set
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