As a first step, some algorithms for finding the best pass were implemented very quickly in order to experiment with the libpredict API and get some sense on how to possibly do the calculations. Some of these calculations will be present in a future version of the libpredict API, and will probably be implemented it in a more consistent, better and more precise way. In particular do some of the tricks done in tracker.cpp seem to result in inconsistent values for AOS and LOS.

When the libpredict API becomes more stable and finished, switch to the functions contained therein and rewrite the algorithms for finding the satellite with the best pass during a given time period. Contribute to libpredict until this is achieved.

The gnuradio flowgraph was implemented based on http://websterling.com/tsro/apt/, but has yet to be tested properly due to other issues. Might need to adjust the filters. Go through the filters.

Should consider to use a class interface to the gnuradio receiver. Or, maybe not.

The RTL-SDR will drift in frequency. This application is meant to be running permanently, and it might be necessary to calibrate the system automatically once in a while.

Look into kalibrate-rtl for automatic calibration.

wxfetch (in theory) outputs sound files recording the signal from each weather satellite pass. Automatic decoding can easily be achieved by setting up a inotifywatcher instance and use e.g. atpdec to decode each sound file as they appear in the folder.

However, it can be interesting to develop a gnuradio block for decoding the APT images directly. Do a clean-up of atpdec, rewrite it into a library and use it to create a gnuradio block.

Properties should not be hard coded in main.cpp:

• Should fetch satellite data from file.
• QTH coordinates should be fetched from command line input (or file).
• Device string to osmosdr should default to RTL-SDR, but be modified from command line.

Use getopts (if I won't do it myself, to future assignee: just be inspired by code present in e.g. https://github.com/ntnu-bioopt/mnf/blob/master/src/main.cpp).