With my previous iPhones, sat in my house iOS has always been able to quickly get a pretty accurate fix on my location (<100m) before GPS reception has been able to refine this to about 5m accuracy. presumably using WiFi location and phone mast reception to achieve this. I think my 4S also achieved this at first. However, for the last couple of weeks I've found that until it gets an accurate GPS fix after 2 or 3 minutes, its accuracy is no longer there - according to Maps.app it always places me about 30 miles to the east of where I am with a MASSIVE margin of error circle. Because it can't get an accurate enough fix reasonably quickly, location-dependent apps either fail (e.g. Siri providing time or weather) or just gives information based on the location 30 miles away. The odd thing is, both of my daughters' iPod touches (both running iOS5) still know where they are to within 100m based on WiFi alone, but even if I disable GPS and network on my 4S, leaving only WiFi running, it still locates me in the wrong place. Is anyone else experiencing a degradation in accuracy for locations provided without GPS?