Support for GPS RTK2

[willishf]

We have setup GPS RTK2 at our farm property and get 1cm accuracy. For a specific robot application we have two GPS receivers on the robot separated by 3ft/90cm. With the 1cm accuracy we get very high precision on robot heading for navigation. In particular, the robot doesn't need to be moving to determine heading and/or pitch as an example.

For a large agricultural drone was thinking it would be interesting to test the same setup for an accurate GPS position. Could also extend the ability to calculate heading/pitch/roll/yaw depending on using multiple GPS units on the drone.

Would need the ability to do the heading/pitch/roll/yaw calculations based on 2 or more GPS locations that are then combined and sent to the iNAV FC software. Refresh rate is a concern but could also serve as a correction factor for drift related to gyro/magnetometer/accelerometer.

How we are addressing this on the robot use case is we have multiple sources of positional information that can indicate confidence in the accuracy of the measurement and use GPS heading over a compass heading as an example. If GPS goes away for a failure or the GPS determines it has low confidence in its GPS-calculated heading(hovering), then use the compass heading. If the compass/magnetometer heading is changing more than it should(near power lines or high vibration), then use the GPS heading even if it has lower confidence.

Just some thoughts on possible functionality that can be added in the future to help on autonomous flight when you are trying to determine the accuracy/reliability of sensors.