A simple VOR receiver git the radial in degree from the VOR.

vortrack [-g gain] [-l interval ] [-r device] frequency (in Mhz)

-l interval : interval in second between two measurements

-g gain in tens of db (ie : -g 400 )

-p ppm : ppm freq shift

-r n : rtl device number (mandatory for rtl sdr)

vortrack 109.25

airwav depends of usb lib and rtlsdr or airspy lib

For rtl sdr :

make -f Makefile.rtl

for airspy :

make -f Makefile.airspy