No. iSTAR does not come with a built in GPS. But it does have a digital compass.
You can however supply an external GPS feed into iSTAR via the USB port. Simply ensure the GPS device you are using can supply a 4800 Baud NMEA data stream.
Here's an example of an external GPS device that we use ourselves to geotag our iSTAR images: http://goo.gl/F9vvMa