Can iPhone 4 use GPS when out of cell tower range?

There seems to be some dispute on whether the iPhone can still get a GPS signal when out of cell tower range, see this archived Apple support thread, for example.

I had a friend out in the woods hunting this weekend, and he said that he couldn't get a location via gps, it was just giving errors.

Does this depend on how the app is coded? Are there specific location-aware mapping apps (like the built-in maps tool) that someone can firm either do or don't work properly with no wireless signal?

Update: I guess its kind of obvious that it entirely depends on how the app is designed. The built-in maps app tries to download map tiles from the internet, and won't be able to do that, so that probably explains his errors.

So my underlying question really is: If I'm going camping, do I need to buy a dedicated "wilderness" GPS like one of these? Or is there an iPhone app that can do the same things when away from a wireless/cell signal?

This summer I took some photos out of cell range and they were all geotagged so it's definitely possible to use GPS out of cell range, but some apps (like the Maps app) use a data connection to get map tiles and routing data, so those features wouldn't work if you're not in range of either cellular data or wifi.

Some of the GPS applications like Tom-Tom or Navigon store the data on the phone and will work without any data signal. However, they're optimized highly for roads and may not help in the wilderness. Also the dedicated "wilderness" GPS might manage better battery life, the iphone doesn't last long when running the GPS in my experience.

I browsed the "Navigation" category on the app store, and "MotionX GPS" and "GPS Kit" are two of the popular apps that claim to support this kind of use, including offline downloading of map packs. (Anyone have any experience with these apps?)

So it appears that this is at least hypothetically possible using the iPhone hardware. Obviously, battery life for an extended trip could be an issue.

Most phones use the cell network to get a rough a idea of where you are (I say rough, but really it cuts it down to a tiny area compared to the size of the Earth aka the coverage of GPS) then use GPS to get the exact location. So if your out of cell range it can take something like up to 20 minutes to get the location (although that was on a Samsung phone and I noticed the iPhone is faster at GPS anyway)

The Apps have a accuracy setting so it's possible that if the accuracy is not accurate enough to use GPS it won't find your location, however I would've thought it would find your location with GPS once it realizes there's no data connection.

Turning my iPhone onto AirPlane mode (effectively taking it out of range of any data connection) and then going onto the default maps app and finding my location takes a while, and switching app while it takes this long makes it timeout.