UKC

The official advice is to activate SIM lock then power off / on. Should result in GPS but no battery-chewing network.

http://support.viewranger.com/wikihelp/index.php/Battery_and_power

Doesn't work on my iPhone 5s - locking the SIM does not stop network access. It's factory unlocked - could this be the issue and does anyone have a solution?

In reply to Gav M:

Airplane mode and then turn on GPS

In reply to Orgsm:

That would work on Android, but not on IOS unless I'm missing something

In reply to Gav M:

This might help:

http://adventurealan.com/iphone4gps.htm

The problem with iPhones is that some of them use a GNSS receiver built into the RF chip, and, when in airplane mode, all RF functions, including GNSS, are turned off.

However, it appears that not all iPhones are the same design, and some include a GNSS receiver chip independent of the main RF chipset. These ought to allow the phone RF circuitry to be disabled, whilst still running the GNSS receiver.

Which design does your iPhone use? Good luck finding that out...

The 'lock SIM card' method came up on a discussion on BPL.