1.14.3.4 The ACU Subsystem Menu

The five icons below the tracking diagram are the ACU subsystem menu. Although looking unimposing, this menu is very important as it gives you access to all parameters of the ACU's subsystems.

Clicking to the TRACKING icon launches a window which shows all parameters of the tracking subsystem. The color of the icon tells about the fault state of the tracking engine (green = OK, red = FAULT). You open the TRACKING subsystem window in order to

• save and recall satellite presets.
• adapt low level tracking parameters like step sizes, averaging times etc.
• enter ephemeris data for antenna positioning or PROGRAM track mode.

The ODU icon opens a window to operate / configure the antenna positioner device. Normally it will not be necessary to access the positioner directly in this ACU configuration, moreover, it might mess up the tracking process if you command the antenna directly. There are however a few situations where you want to see all antenna parameters:

• The positioner shows a fault (red icon) and you want to know what the reason for the fault is.
• You want to move the antenna manually in small steps, e.g for the pointing calibration or for measurements. The SatService ACU ODM device window provides step movement buttons which help you to do this efficiently.

The BCRX icon opens a window directly to operate / configure the beacon receiver attached to the ACU. This window is required to set other beacon receiver parameter than the frequency or receive polarization.

The 'VIEW PLOT' button opens a separate graphical Y/T display window which gives more detailed information about what the tracking engine did during the recorded 48 hours. It provides variable scales, and permits to display additional information. The display shows either the azimuth or the elevation pointing found at the beginning of each tracking step together with the beacon level measured at this time. The following additional information may be included to the diagram:

• --- If this toolbar button is pressed, the diagram shows the search step and the beacon level change resulting from this as a dimmed peak at the left edge of each data point. You can easily monitor the signal degradation which is caused temporarily by the tracking search steps with this function enabled.
• --- If this toolbar button is pressed, the diagram includes the evaluated peak positions. In STEP track mode, this actually is the location where the antenna gets moved to. In ADAPTIVE tracking mode, the antenna moves to the location resulting from the mathematical model which is computed from the step track peaks. In the latter case, the peak positions may be interpreted as the actual difference between the modeled pointing and the peak position.

Clicking to the 'VIEW LOG' button opens a window where the program shows a live report what the tracking engine actually is doing. The log in this window is cleared with each new tracking step. If 'Y/T PLOT' diagram shows many unsuccessful tracking steps, watching the log reports may give an explanation why the tracking engine discards so many steps.