Ovi Maps 3.01 and 3.03 seem to randomly put you in places your not eg...in the sea, on a house etc or the GPS signal cuts out.
Well, Im not holding my breath for Nokia Customer service to help as they "Dont seem to be aware of the problem" Im awaiting a callback from a Nokia specialist....
I saw a you tube video of a guy getting better GPS reception when he perched his N97 on a Iron Bar, earthing the phone(there's the metal strip on the edges) and watched how he lost his GPS reception momentarary when he took it away from the Iron bar.
Well, I went to a supermarket tonight and got some Tin Foil wrap, you might have some at home right now....I know I did'nt

On my Cradle at the bottom I wraped the Tin foil around the botton and also tried some Tin at the back support. I then put the N97 in the Cradle and observed that while the accuracy was still jumping around, I was getting some low teens, mid and high teens in metres, 10 meters and even 9 Meters!!
I ended up only using the foil at the bottom of my cradle as this seemed to have best results for earthing the N97. You may want to experiment yourself.
I have definalty noticed less drag observing my red dot on the map and while navigating using A-GPS, the drag is still there slightly but it should make your navigation a wee bit more accurate in the car...Yay!!
Let me know if this works for you