Tke Sky at a Glance

Although gpredict has some very good satellite pass prediction functions, I have been missing a sky at a glance feature that can quickly show when the satellites will be up during the next X hours. After a few weeks of casual hacking, this feature is now ready for testing.

I have first seen this feature in XEphem where it shows the night at a glance. Since XEphem is a planetarium program, the night at a glance function focuses on the Sun, the Moon, and the planets. It is centered around midnight and spans 12 hours in both directions.

For gpredict a more apropriate time span is to start now and X hours ahead, X being a user configurable parameter. A screenshot of the function in action is shown below.

Gpredict - Sky at a glance

The sky at a glance prediction function is accessed from the module pop-up menu and is linked to each individual module. Therefore, it will use the ground station info and satellites that are associated to the module.

The colours for the passes can be configured via the preferences dialogue and the first 10 satellites can have different colours. After 10 satellites the colours are repeated. The mouse can be used to read the time corresponding to the horizontal position on the graph.

There are still some rough edges primarily regarding round off the time to the closes hour. However, it is obvious when that goes wrong, since the time will suddenly jump two hours instead of one. In those cases, the time read using the mouse is still correct.

Author: Alexandru Csete

Embedded software engineer in the satcom industry during the day. Radio amateur and SDR hacker during the night.