Many tech journalists, myself included, were expecting new iPhone firmware at Macworld this week. And we got it - I upgraded to v1.1.3 yesterday, right after the Steve Jobs keynote.

Apple rolled out six new features with the new 1.1.3 iPhone firmware - Google Maps with location-finding; Web Clips; customisable home screens; the ability to send text messages to multiple people (finally); plus video chaptering and onscreen lyrics.


Location-finding via Google

The most useful addition to the 1.1.3 iPhone update is the ability to pinpoint your geographical location using the Google Maps application. And without using GPS. Google added non-GPS location-finding to Google Maps on Symbian S60, Blackberry and Windows Mobile-powered phones in November last year.

On the iPhone, Google's location-finding works using a combination of GSM and Wi-Fi triangulation technologies. Google Maps can get a very basic geographical fix on your position by working out where your phone is in relation to any nearby GSM signal transmitters.

But the distance between transmitters usually means that GSM-based location-finding on its own is vague. So, an iPhone will know that you're in, say, Bath, but it won't be able to tell exactly where.

To get a more accurate fix, the updated Google Maps app also uses unique Wi-Fi data provided by Skyhook Wireless.


Wi-Fi Positioning System

Skyhook has developed what it calls a Wi-Fi Positioning System (WPS), which uses the signals that are broadcast from local Wi-Fi networks and public wireless hotspots to narrow down your location to within 20 metres.

So where GSM triangulation alone will tell you you're in Bath, somewhere, WPS can be much more precise. It can inform you that you're in Bath, north of the river Avon, on a road called 'The Ambury'. At least, that's where I'm writing this post from. And a 20-metre accuracy isn't bad. Especially when you compare it to the 10-metre accuracy of GPS.

Of course, GPS is available everywhere in the UK. WPS isn't. But as Apple can't magically add GPS tech to its existing iPhones, WPS is the next best thing.