Time-to-First-Fix with N810 GPS
 

I've been a bit disappointed with the time-to-first-fix (TTFF) of the
N810 GPS. Typically around 3 minutes compared to 45 seconds on my 5 year old Garmin (also internal antenna, pocket sized device). I have heard of one user totally unable to get a fix in 25 minutes after flying in to Europe.

I complained to Nokia and they suggest buying one of their Bluetooth GPS sets. Not very satisfactory - why should they get better performance without an external antenna ?
Design compromise in the N810 ? Screwup ? The N810 I believe uses the TI GPS5300 chip, marketed to OEMS as having a rapid TTFF and suitable for cellphones with Assisted GPS - AFAIK a rough location from celltowers that enables a faster fix for 911 calls. So I'd think it ought to be possible to
give the chip a previous fix or guessed location over the I2C or serial interface and get a fix in a few seconds. Unless the thing has been wired up unidirectional.

What kind of fix times have other users been getting ?

Re: Time-to-First-Fix with N810 GPS
 

Cold fix times of 60 seconds to never. Probably an average of 2-6 minutes under ideal situations. The software does not feed back any almanac data to speed up fix times as far as I know. It's a firmware issue that can be improved if Nokia invested some time and effort.

Re: Time-to-First-Fix with N810 GPS
 

My dedicated Siemens-Fujitsu Loox 100 Navigation unit also needs about 3-4 minutes to fix. So I guess the N810 isn't that much out of bounds....

Re: Time-to-First-Fix with N810 GPS
 

After owning my n810 for a couple of months now, I have noticed that occasionally it appears that the GPS doesn't even try to get a fix... opening up the Map satellite dialog sometimes shows that not even the signal from a single sat. is being acquired.

un-checking the GPS box, closing the map, re-opening the map, clicking on the crosshairs and then re-enabling the GPS usually fixes this problem for me.

Supposedly navigation software updates are coming with Diablo, so I like to think that we will see improvements in fairly short order.

I really hope that Nokia is taking this problem seriously though. The n810 is an expensive device with GPS as one of its main selling points.

Re: Time-to-First-Fix with N810 GPS
 

Try holding it vertical and facing the south. See: http://www.internettablettalk.com/fo...ight=gps+south

Re: Time-to-First-Fix with N810 GPS
 

It's a bit hard to do this if it's mounted in my car :cool:
And I don't want to know my neighbors thinking if I pray and point my tablet to south before enter my car :D

This is the one and only solution and I hope it gets an update sooner than releasing N810-wimax
For real buyers of the N810, it's a pain...

Re: Time-to-First-Fix with N810 GPS
 

It is strange, but it is inconsistent. It seems if you properly shut it down it will remember the location and I've seen restarts in 30 seconds or less. I've also had good indoors (near windows) performance. I've also had it take several minutes with a clear sky.

I've been playing with the $70/10Hz WinTec I posted in the accessories thread. I've seen similar things.

As best I can tell, if you are indoors or otherwise have something that will make a fix difficult and leave it on, it will "forget" the time/location after a bit, probably assuming it is wrong if it can't find what should be there.

Also it needs somewhat more strength to do a lock where it will pull data from the satellite instead of just using it for tracking. That also seems to be key since it won't get the ephemeris until it locks, and won't know the orbit to compute position until it has the ephemeris.

So in summary, it needs REALLY good signals for a first fix (and it might need it per satellite), and will need to update that fix occasionally. So one that goes well above 30db for several seconds with a lock will be remembered, but one that never quite gets there, or doesn't for long enough won't.

Re: Time-to-First-Fix with N810 GPS
 

https://bugs.maemo.org/show_bug.cgi?id=2878

Here is the bug... vote for it. It's the already the most voted bug in their database.

Re: Time-to-First-Fix with N810 GPS
 

Thanks for posting that- I've voted for it in the past, and we should be sticking it in every n810 gps related post

Re: Time-to-First-Fix with N810 GPS
 

Hmmm I might be onto something. I've managed to get a lock on the first floor of my 2 story house 10' from any exterior walls. Yes, it took a few minutes, but that's kinda incredible from my understanding of GPS.