does gps data transfer baud rate matter ?

[gune]

hi:
does gps data transfer rate matter with regards to speed of location updating etc?

[mikealder]

Not really, the NMEA protocol sends very small data packets through to the PDA/ phone etc. Even at 4800 Baud it works quite well, at the higher speeds the port is left for longer with nothing to do.

The largest overhead that can delay the screen refresh is the actual redraw of the image, also enabling POI's can seriously slow the PDA down. VGA equipped devices suffer as the processor has four times the amount of work to do when compared to the more usual QVGA screens.

If you look at the NMEA sentences transmitted over a single second burst you will find its not too much in terms of data bits, you need a program to display the raw NMEA data, then look for the transmitted sentences, the text strings start with a $ symbol, then contain the Lat, long, time, date, speed, heading etc. I use my own program for doing this but it will only work with the Widcomm Bluetooth stack, any device using Microsoft (WM2005) will not work. - Mike

[gune]

hi mike:

[mikealder]

It can do, it will depend how well designed the hardware is and how much spare memory the program has avail for it to use, the bigest problem in slowing the hardware down is normally down to the POI's being enabled, rather than set to "warn when near" - I wouldn't worry too much about the screen refresh rate, you only notice the slow down when comparing units next to each other, and as they are different devices/ processors etc it is an unfair comparison. The basic fact of the screen containing four times as many pixels does give the processor more work to do though - Mike

[neil01]

It is also worth noting, that on some equipment it is not possible to increase the baud rate - it simply will not work. The default value also being the maximum value.

[philpugh]

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