We want to use a dual GPS system with two Here3 GPS’s. I was wondering what limitations there are to where on the wings the GPS’s are placed. For example, do they have to be on the very ends of the wings? Can they be mounted slightly tilted in? What if there is a winglet on the edge of the plane potentially blocking it from one side?
@stupidplaneflyer general recommendation is that GPS should have a clear view of the sky (i.e. approx 15deg from horizon on either side atleast) for best performance.
If you intend on using the Compass from the Here4 module and the GPS is mounted in an awkward angle that is not aligned with Flight Controller in one of the angles listed here https://github.com/ArduPilot/ardupilot/blob/901280902abab170925711a3b5ead89327a715b9/libraries/AP_Math/rotations.h#L28 then you are going to end up with failed calibration or bad AHRS calculations.
Also, during calibration the orientation is also estimated although it is recommended to set it up yourself, or atleast verify that it resolved to the correct Orientation.