WildBill,
I think you have hit the nail on the head. I tried this on a mega with separate buffers for each and it works perfectly.
I am thinking that to make this work on the uno, i could instead declare getups() as an int and have it return 1 when it gets a full sentence and then call it
while(getgps() != 1);
make sense?
This will half my data acquisition rate - on the mega using hardware serial I get pairs of fixes separated by the approx 1 second xmit rate of the NMEA units
Really really appreciate your input!
Geoguy - the NMEA depth sounder is not too expensive - about $170 - so you may wish to consider using it. Once I get some nice code working (either uno or mega) I will share.
Best wishes for this fine long weekend!
Peter