My little hand-held GPS is a 12 year old Garmin I rescued from the surplus pile at work. It has about a 100 meter precision ( by repeatability testing). I haven't got a new one with all the bells and whistles since mine already requires a 50 page instruction manual and I haven't come anywhere near exhausting its capabilities.

At work, we have a backpack unit with about a 10 meter precision, which interfaces with our GIS software. By downloading its data and running special software with access to online correction files, and by picking up signals from supplementary ground-based transmitters, the precision can be improved to about a meter.

Survey capable unts are able to integrate signals over time and can provide precision down to the centimeter range. It's a long way from the 1000 meter precision a skilled operator under ideal conditions can get from a sextant.