GPS Heading/Yaw (aka Moving Baseline)

PX4 Guide for RTK

PX4 Firmware GPS Heading with Dual u-blox F9P is supported in the both DroneCAN and UART version. The DroneCAN version requires a different firmware and can be found in the guide below.

RTK GPS Heading with Dual u-blox F9PPX4 Autopilot

PX4 AutopilotPX4 Autopilot

Holybro H-RTK ZED-F9P RTK Rover (DroneCAN variant)PX4 Autopilot

Ardupilot Wiki for RTK

Ardupilot GPS Heading with Dual u-blox F9P is supported in both the UART and DroneCAN version.

GPS for Yaw (aka Moving Baseline) — Copter documentationardupilot.org

GPS/Compass (landing page) — Copter documentationardupilot.org