The position of the GPS antenna is absolutely critical to the speed of acquiring the very weak satellite signals. This is why all the in-car GPS's have their antenna positioned on the roof of the car where you have a clear view of the sky. When you have a dashboard mounting GPS, the antenna can only see half of the sky (with weakened signal by the windshield) the other half blocked by the steel roof.

Clearly, by moving the antenna as far forward under the windshield as possible will have a better coverage of the sky. But the antenna is integrated into the N810, mounting it too far away from the driver will make the N810 less accessible. With no external antenna connector to allow the placement of the antenna away from the main unit, there isn't much can be done.

Nokia has included a dashboard mounting kit with the N810, and yet, not allowing external GPS antenna to be connected to it is an oversight. Similar parallelism can be drawn with the integrated web cam that has no application to use it. A communication break down between the marketing and technical guys.