A number of inexpensive GPS units send send fix information at 5Hz. Accommodating this rate would
be a nice feature.
I have an iTrek Z1/iBlue 757 based on an MTK chip, and
it seems to overwhelm roadnave at 0.2 Time and 200ms Fix. The track follows for a short time, and then freezes.
A baud rate of 11520 might also be needed?