GPS $PMTK220 versus $PMTK300

Attached is the “GlobalTop PMTK Command Packet” document which spells out the various PMTK commands for their GPS products based on MediaTek GPS chips. I have the Adafruit Ultimate which has latest MT3339 capable of 10Hz

I’ve successfully changed the rate my GPS updates fixes and reports sentences to 300ms using the command $PMTK300,300,0,0,0,0*

I’ve found posts (on Adafruit forum) suggesting $PMTK220 increases reporting rate but not fix rate, i.e. the fixes in consecutive sentences are the same until GPS actually takes a new fix.

My question: What is purpose of $PMTK220 command, it seems $PMTK300 does it all?


PMTK_A08.pdf (405 KB)