I was under the impression that the iPhone received timestamps along with GPS location data. While I can't say its not true for the internal database, it seems to be for the EXIF data attached to photos taken by the iPhone's camera.
I ran a test by turning off automatic date/time settings, ensuring my correct timezone was set.
I took a photo (
IMG_1692), rolled back the time by two hours and took another (
Using Phil Harvey's EXIF Editor, I retrieved this output:
$ exiftool IMG_1692.JPG | grep Time File Modification Date/Time : 2012:04:29 22:51:46+10:00 Exposure Time : 1/15 Date/Time Original : 2012:04:29 22:51:46 GPS Time Stamp : 13:51:00 $ exiftool IMG_1693.JPG | grep Time File Modification Date/Time : 2012:04:29 20:51:32+10:00 Exposure Time : 1/15 Date/Time Original : 2012:04:29 20:51:32 GPS Time Stamp : 11:40:50
You can clearly see the two hour difference in the file timestamp, as well as the GPS time!
Am I correct in this assertion that the GPS timestamp doesn't come from the GPS at all? Or am I missing something?