Based on the sample data provided by Loris
I have written some code to produce an Allan Variance plot of the data. The program source code is ISO C++98, and should compile with any standards-compliant compiler. G++ 4.4 tested, I expect MSVC 2k8 or higher to also handle the file just fine.
This particular program is somewhat specific to the data provided by Loris. It expects 16x oversampled sums, in integer ADC counts. The code performs the floating-point division back to native counts itself. Just compile and link the program in one command:
$ gcc -o allan_variance allan_variance.cpp
To run the program, provide it with a data file and the sampling interval. The data file must be provided as a list of whitespace-separated ADC samples, with six channels per entry. The first three channels are treated as x, y, and z axis gyros, and the remaining three channels are ignored.
Prior to actually using the data file, I massaged it somewhat. The original file has some weird line endings, something like \r\r\n. So I piped it through dos2unix and removed the blank lines with sed.
Over the entire sample period, the noise is dominated by white noise in the sensor, not by bias drift. I expect that the bias drift won't show up until the data stream is much longer, on the order of half an hour or so. Gnumeric was used to produce the plot.