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of testing at AvL, all of the configuration parameters and files for every antenna system are recorded
and stored by the Service group for future reference.
7.3.6 Power-On Calibration
Calibration is not a process that occurs only once during the factory assembly and test of AvL
antenna systems. It is an important automatic step that is performed every time the antenna is
powered on for normal operation. This calibration step is referred to as the “Home” process. It is
also a system command that figures prominently on all of the AAQ GUIs. The main purpose of the
Home process is to calibrate the primary position feedback devices used on most of AvL’s antenna
systems. The optical encoders mounted on the AZ and EL motors and the potentiometer mounted
on the POL motor would be an example of this.
These devices are high resolution and very precise, but they provide only relative angular position
measurements with no reliable absolute reference point. For this reason, when the antenna system
powers on it does not know with certainty where the antenna is pointing or where the positioner’s
axes are relative to hardware safety limits. Executing the Home command/process moves the
antenna to known reference points using inclinometer and potentiometer feedback and a magnetic
reed switch that together allow the AAQ to assign a reliable absolute position value to the readings
provided by the encoders.
7.3.7 Product Lifetime
AvL designs antennas for a long service lifetime with minimal maintenance required. However, it
may become necessary at some point to re-calibrate the antenna system due to replacement of a
sensor or some other critical component of the antenna system. AAQ software includes several
automated calibration (Auto-Cal) routines to assist the user in many of these situations. When
necessary, step-by-step instructions may be provided to address special cases. A properly trained
System Integrator technician or end-user, with sufficient log-in privileges, is able to safely and
accurately execute all the calibration steps necessary to maintain the antenna system in good
working order.