[amsat-bb] High resolution serial antenna tracking protocol?

I have been working on an antenna tracking system using a very heavy duty CCTV pan and tilt head which uses large stepper motors. I have built a new control system that accepts Yaesu serial data commands from SatPC32 and drives the stepper motors to the correct position. The Yaesu protocol only works in whole degrees. Does anyone know of a serial protocol that allows fractional degree or minute data? I know our application doesn't need it but I would like to test the hardware to it's limit! Dick G4BBH