I did a quick google search and came up with no solid answers. I have an iPhone 4s on iOS 6.1.3. GPS location is wrong or lags when navigating, with the location skipping about every 30 seconds, making it hard to use for real time navigation. Problem happens in both Google maps and Apple Maps. Today I went biking and used runtastic and same problem occurred as well. Runtastic alerted me to turn on GPS prior starting but it was already on.