Nav system was batty after jump start

I left the headlights on in my 2004 Prius again (exited through the passenger door so they didn't shut off automatically). The battery died and so I had to jump it.

After jumping it, my Nav system was confused. It thought I'm about 6 miles from where I actually was. The arrow icon moves whenever the car is in motion, but the map shows a completely different area. I set the destination to my home, and when I got home it said I still had 6.6 miles to go.

We had to try a couple of times to jump start it because of poor connections, so I'm guessing that the power probably got cut off while the nav system was loading the firmware from the DVD (the "system loading don't turn power off" screen).

So after the 12V battery was charged, I tried "rebooting" the Nav system by disconnecting the white connectors on the 12V battery. The "system loading don't turn power off" screen came up, so I think it reloaded the firmware. But it still didn't know where I was. I noticed that the "GPS" label was not displayed on the screen, so it must have been using dead reckoning to figure out where I was.

A couple of minutes after the reboot, the GPS indicator came on and all of a sudden it had my correct location. I guess it must have taken that long for it to find the satellites. So moral of the story: If your nav system goes batty, try rebooting it by disconnecting the battery connector and then wait a few minutes.

What impresses me is how well the dead reckoning seems to have worked... I drove approximately 30 miles on a twisty highway, and it was still only 6.6 miles off. I would have thought it would have gotten confused about which was was North with that much driving, but it was still pointing approximately correct. I almost can't believe it could have maintained the directional heading from just the yaw sensor... that must be a great sensor!