GPS Info

We are using an Ardusimple RTK heading GPS system. Rover Heading System Base Station RTK Communication System

Within each of those product pages you can scroll down to find a documentation tab with relevant info.

The two main tutorials are base station set up and heading RTK setup. This is best done on windows as the UCenter software is built for it, though in theory it could be done in Linux.

The general setup for running the gps is to connect the base station to the GPS antenna, and connect that to a usb power source (connected to power + GPS side). Leave the antenna still after powering it on, the system needs a few minutes to get a position lock. The rover attaches to its antennas, and is connected to the pixhawk via Telem1 (connected to power + pixhawk on the main board). You can tell that it is getting the RTK corrections when the no RTK status LED on the rover stays off.

You should now have centimeter level accurate position and degree level accurate heading (position in one of the raw GPS topics from mavros, change this text to the actual topic name) (heading in another topic, it is in units of degrees * 1000 or something like that, also add topic name and more accurate description of units here).

Contacting Ardusimple support via email worked well for me, I would recommend doing so.

Note: The heading info will output a large value like 6.3ish million or something like that if the two antenna are not close to being parallel to the earth, so if the boat is rocking you cannot expect to always have the heading info.

Note: The quality of the GPS signal is best when there is nothing above the antennas, especially not any EM noise. So having the antennas high up, above the electronics is best, though not necessary.