My best recommendation for people with offline GPS woes would be GPSJinni. It will give you some insight into if anything (and what) is actually happening with GPS.

Install it, start it, hit the Satellites button and wait. After some time (depending on the satellite constellation, location and orientation of the device), white bars should appear indicating the PRN and relative signal strength of the satellites that are currently being received. They will change over time and possibly even perform a little 'dance', i.e. disappearing and reappearing, especially in case of reflected signals being received.

Generally ... the more bars, the better! And note that for a fix to be made, you will need at least 4 of those bars with a reasonable (i.e. 60% or better) strength. And, on a device that has no current almanach and ephemeris data, time. Ephemeris data takes at least 2 minutes, full almanach information 15 minutes to trickle down over the 50 baud satellite data stream (incidentally this is exactly where A-GPS comes in: it allows that this paramount data reaches the device in the blink of an eye via network, thus speeding up the process tremendously).

An unobstructed view of the horizon will tend to help greatly (unless you're close to the equator), as GPS satellites often tend to be visible at a fairly low elevation. Note that in the northern hemisphere, this view should be facing south, whereas in the southern hemisphere, it would be north. (Don't shoot me if some detail is off here, all of this is from memory; I was doing some research on improving lousy GPS reception some years back.)

In any case, back to GPSJinni -- at some point, provided enough white bars have been visible for long enough, some will eventually turn green: congratulations, you now have a fix! Any application using the location service now should be able to tell you where you are, be it Maemo Mapper, OVI Maps or whatever.

Incidentally, from my personal observation here and during my aforementioned research, GPS is one of the most less understood and most highly overrated technologies when it comes to the general public. People seem to expect miracles from (especially consumer) GPS devices, when in fact, they are inherently "unreliable" beasts due to the nature of the entire system and the rather flaky antennas that tend to be used in GPS add-ons to general-purpose devices like phones.

No idea, but it's probably those overblown scenarious depicted in Hollywood productions where a modern-day MacGyver uses GPS to track someone on the lowest level of an abandoned coal mine that causes people to have these unrealistic expectations.

Simply put (or as Scotty would say): A canna' change the laws of physics!

So how good is the N900 GPS? Well, worse than my M-241 data logger, just somewhat worse than my Nokia 6210 Navigator. But a loooooong way better than a Siemens SXG-75 or Motorola E-1000 phone of days past. It is able to get a fix just from signals reflected by neighbouring buildings at a window facing north (I'm in the northern hemisphere, so, as mentioned above, worst case) in an amiable time (around 2-3 minutes, provided it's not a really bad constellation and its almanach data is not outdated).

Whoops, this had become rather long-ish bordering on rant

Hope it helps someone anyway.

Regards,

Chris.