Title is misleading - as far as I know centimeter accuracy is only possible with an RTK base station in the area where you're using the GPS, e.g. in a survey. I'm guessing the chipset allows capturing of raw data that can be post-processed.
>> NS-RAW: carrier phase raw measurement GPS receiver, max 5Hz update rate, RTKLIB supported S1315F-RAW in the form of plug-and-play NavSpark
There is also an FAA graph of GPS measurement accuracy[1] which I'm guessing is the source of various "accurate to 2.2m" claims I have seen.
[0]http://en.wikipedia.org/wiki/Wide_Area_Augmentation_System#C...
[1]http://www.gps.gov/systems/gps/performance/accuracy/histogra...