When driving around signal strength can sometime vary. What I've found is that this confuses the mapping program (I use Google maps) and it gives voice prompts based on the old location which in turn is confusing for the driver. Are there any apps that can compute a route online but then.provide directions based on current location even in the absence of signal strength? If the 5s has a true GPS receiver (does it?), then it should be possible. (FWIW I have a 5s.) Slightly off topic. I started using Google Maps because I had an iPhone 4 previously and Apple didn't have turn-by-turn directions. Now that I have a 5s, I'm quite disappointed with Apple maps and I'm still forced to use Google. Hopefully Apple's recent acquisition will help.