8M8

Hey all,

I haven't come across anyone who's mentioned this yet. I am not even sure if it's a normal occurence and thats why I am here confirming it with you guys.

When I drive with my GPS on, the voice prompts are on time and accurate with my vehicles actual position when turning etc. However if I look at the map, my position(green arrow) is behind and not accurate with my actual position. I've got into trouble a couple of occasions because of this and have started to rely on the voice prompts more. Has anyone else had the same issue and is there a fix

I have the Dell Bluetooth GPS package with BT 309 receiver. I have loaded all the maps(2GB) onto a 4GB SD card and have a X51 520Mhz PDA. I initially had the maps loaded on to my 6GB microdrive. I thought that that was the issue but apprently not. Any help, suggestions, ideas would be highly appreciated.

jackb_guppy

I see lag in the GPS software I use too. Normally it is 1 second behind. I can tell by it showing that I *WILL BE* driving cross a street and I *AM* driving cross street. This is quite normal. And voice prompts tend to right because it is project forward where you will be not showing where you are.

Remember: 88ft/sec = 60miles/hr. Some GPS can be off as much as 100ft N/S and E/W PER READING and that is once per second, from rounding errors. So the GPS software is adjusting and accounting for times where it thinks you are going over 120 MPH in a direction that you are not heading. Newer receivers are better, but the same but smaller issues can be found.

Also note that the Lat/Long in the maps may not align to actual Lat/Long. There are errors in map encoding as well. I live in Memphis, and some maps here (even looking at google) at off.

So a lot of little errors makes for a good approximation that you use to drive around.

Oh yeah, watch the road, not the map screen ;-)

rl1024

Sometimes it's hard to know when/where to turn, so I glance at the street name/direction every once in a while.
For me, the summary/list of turns is easier to use than the map while driving.

JakeRich

Read GPS201 linked in my sig. That explains the lag in ALL gps units.

jackb_guppy

JakeRich I loved this part:

Quote:

Only when the next fix arrives does it jump back to follow where you actually are, and even then the snap to road function can delay the full impact another second or two. Eventually you get far enough from the commanded route and it gives up snapping you to the route and re-plans. It’s not bad, just a quirk of predictive screen refreshes.

I see this with Mapopolis on freeways. I live in area where the old highway is also main drag with lots of lights. Mapopolis likes me to take that road over the freeway, because I live north of it. At every off ramp Mapopolis directs me to exit, than shows me exiting, crossing under the freeway, then 3 second later BONG! reroutes me to take the next exit. (PS: I have snap-to turned off ;-)

I do not find it an issue, just makes me happy. Like the day I got the software to tell me make a U-TURN away from my house which I was my desination. Basicily IT HAS A PLAN, NOW FOLLOW IT!!!