5Hz GPS at 4800 baud

[NoahF]

I am planning a NMEA0183 GPS which operates at 5Hz (5 position updates per second) as input to my AFS. This GPS will be providing position input to four serial devices. Unfortunately, one of these devices limits max baud rate to 4800 baud.

Does anybody know if 4800 baud is a high enough serial data rate to get all 5 position updates per second into the AFS? I suspect that it is not. If not, how does the AFS performance change (degrade) if it gets only one position update per second as opposed to five?

Alternately, I could get yet another GPS and feed the device with the low data rate requirement with that, which would allow me to ramp up the data rate into the AFS to 9600 baud. But it is not clear to me that even 9600 baud is a high enough data rate to get 5 updates per second.

Can anybody shed some light on this?

[Trevor Conroy]

Noah, if you slow it down to 4800 baud you will be right on the edge of 4 or 5 updates per second. That is assuming you only have the GGA and RMC labels turned on. If it is the Garmin GPS-18 you are using, it can be configured as such.

[NoahF]

Thanks Trevor. How does the AFS behave differently at 1 Hz update rate vs. 5 Hz. In other words, why would I want 5 position reports per second?

[Trevor Conroy]

The more position reports you have, the better the terrain "animation" will be. If you use a GPS with a slow update rate, like a Garmin 496 outputs, you will find the terrain will jump around a bit.