3.14.3.1 The Pointing Display

The area in the upper right part of the window shows the actual antenna pointing and provides entry fields to move the antenna to a given position. The example below is taken from an antenna which is not equipped with a polarization motor, the polarization angle display is empty therefore.

The fields labeled 'azimuth', 'elevation' and 'polarization' show the actual antenna pointing as read out from the angle encoders. For azimuth and elevation there is also a strip chart display of the angle. If you choose a high resolution scale for the chart, you can watch the antenna doing the tracking steps in the chart. Click with the right mouse button into the chart to get a pop-up menu for scales and other display options.

The 'nominal' fields define the nominal antenna pointing for the actual satellite. The nominal pointing describes the center of the satellite's path over 24 hours.

• If you store the antenna pointing and the tracking parameters as a ACU preset, the software stores the nominal pointing. If you recall the preset, the software moves the antenna to the stored pointing and starts tracking there in the operation mode stored with the preset.
• The antenna moves to the nominal position, if you click to the 'RESET POSITION' button.
• The absolute tracking limits configured in the TRACKING subsystem refer to the nominal antenna pointing.

If you change a nominal pointing value while the antenna has tracking switched on, this only moves the reference point for the tracking limits. The antenna is under control of the tracking engine and does not move due to this change.

If the ACU tracking mode is set OFF, the antenna behaves differently. In this case changes of the nominal value let the antenna move immediately to the selected position.

Finally, the 'offset' fields indicate the actual difference between the real antenna pointing and the nominal position.