GPX requires a NMEA compatible GPS device and uses GPGGA, GPRMC,
GPGSV and GPGSA GPS-Sentences. The NMEA Data must be delivered over
(virtual) serial port. Since GPX is coded in csharp, it requires
the Microsoft
DotNet runtime. GPX is free opensource software,
you may use it in any way you want, as long as you mention the
origin.