I've added the Xona X1 pilot and data codes to my Github repository supporting the various GNSS signals:
https://github.com/pmonta/GNSS-DSP-tools
There are also preliminary acquisition and tracking programs similar to the others. In the case of the Xona signals, though, they really need either external aiding or a third-order loop---with current settings, the carrier loop maintains lock but with a nonzero steady-state phase error due to the high dynamics.
A 13-second track of X1 data:
A closeup of one of the data frames:
A frame of data is sent every second, with each frame using about half of the 1-second slot. (No FEC yet?) Some multipath is visible (causing the amplitude fluctuations), even over this short time interval. It's hard to make much of the data without an ICD. Maybe I should invert the data spreading code, since it seems semantically more likely that most of the data bits would be 0 rather than 1.