If you need precise GNSS for your robots then you need RTK. If you don't know much about RTK, you may lose a lot of money (and hair) on weak RTK GNSS systems. I've written a post to show the beginner what they need for a super solid precision RTK GNSS. Included are specific companies and prices -- I've not seen this guide anywhere else.
Here's hoping it saves you time & money!
What flight controllers working on k501g? Is Pixhawk1 working on k501g?
Yes, Pixhawk w/ ArduPilot via https://github.com/ArduPilot/ardupilot/blob/master/libraries/AP_GPS...