Got lost help

[desy6969]

Can anyone tell me this used sat-nav to take me to london on a sunday evening at 8pm.
Used same sat-nav to take me to same location from same starting point as before only thing different is the day monday morning at 8am.
Why does the unit navigate me on a completely different route than before
The unit is a Garmin i3 i don't think they have live traffic update.
I'm a bit puzzled as to why it did this.
I'm running latest up to date map software. The first job it done was fine but on the second journey it took me deep into the belly of london and lost it's signal from the tall buildings so i was stuffed all round had to stop and ask for directions to save my butt. .
The unit has worked well on the whole but i'm left with dout now when going anywhere near london.

[mars.1]

If i was you and you go up the city a lot, then i would buy in an external antenna to improve signal whilst driving in between tall buildings. Also have you changed the route preference from faster time to shorter distance or from shorter distance to faster time as this would send you on a different route to the same destination. Last of all the i3 does not give traffic updates.

[mars.1]

Also changing the gps setting from normal to waas/egnos can make a difference on route calculations when going to a destination.

[desy6969]

Thanks for your reply mars 1
I had not changed anything from before in settings i always use shortest distance calculation.
I will keep in mind the roof top arial thanks.

[MaFt]

it could b something as simple as being a few feet different from your revious starting position. or if the satellite fix was not very accurate (i.e. just turned on and not got full fix but enough to navigate) and thought you were in a slightly different position - resulting in a route that could have ben a few seconds faster or a few feet shorter.

MaFt

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