@gunni - no GPS unit uses it's internal clock. The time differences involved require an atomic clock. This baby sits in space as part of the system and is one of the sattelites you need a lock on for GPS to work.

N900 requires a net connection to get a lock because Nokia were too lazy to work on the device and code to make it function otherwise.

So it's really a software matter?

Thats what i meant.

To get some closure on this topic: Starting up gpsjinni before opening Maps helps get a lock even without an Internet connection. I guess the Maps developers should beg/borrow/steal the code from gpszinni.

n900 uses internet connection to even download maps as per the coordinates it receives from the gps chip...


in case it wasnt already stated in the thread

Ovi Maps does not download new maps, if they were pre-loaded.

Other map applications may download map data (or some allow it to be preloaded).

how much space reasonable vector maps of all the most common places where people are expected to bring their N900 to would take?

To strip this down and answer some hardware and gps-tech questions.

If it asks for network connection depends on your settings -> location.

The word you are looking for is "Satellite Cache" which will be downloaded (or better just recieved) from satellites at view.
This may take up to 12 minutes and at least 120 seconds.
The antennas power is pretty good as I get a fix in some buildings from reflection and/or direct signal. In case of A-GPS the onboard system downloads the cache from a server which has information from a nearby stationary GPS system. How does it know where you are? It knows the celltower-IDs around you.

Easy! No you can't! Why? If that would be possible you would get a fix in the second you get the ID of 3 sats.
The US military updates satellite's positions, some go offline for maintenance and come back up at another spot as one died and so on. Normaly you get a fix if you had one in the last 24h at the spot where you turned your gps off but not for sure. They are drifting and correction of positions are calculated constantly.

Please at least try to read on some information before you ask general questions on hardware and technical functions of things like "how does gps work?" Most of the hardware specs are at wiki.maemo.org... (just read the 100s+ thread asking about the IR device)

Any four GPS satellites are enough to get a fix (unless they all lay along a straight line from the GPS receiver point of view). Three are enough if the receiver elevation is known.

There is no special GPS satellite for time. The reason one more degree of freedom is required than for the purely geometric calculations is to figure out what the time is at the GPS receiver.

All each satellite transmits is its ID, the time, and what its ephemeris is, over and over, very slowly. The receiver needs to calculate its time, where each visible satellite is, and measure the distance to each satellite. Then it calculates where it is. It measures the distance to each satellite by subtracting the time the message was sent from the time that it arrived.

That is an unfair oversimplification.

However, the refusal to give up nagging for an internet connection after the user has repeatedly rejected is another matter.

I remember a while ago i was in a cell phone store, from a carrier, another customer was browsing and asked if a certain model had GPS, i knew it had, i told him, but the chick from the store insisted he would have to hire the GPS service from the carrier, as if it wasn't a physical property of the device itself, it was a lost battle