# 듀얼 u-blox F9P를 사용한 RTK GPS 헤딩

기체에 장착한 두 개의 u-blox F9P RTK GPS 모듈을 사용하여 방향각을 정확하게 계산할 수 있습니다 (즉, 나침반 기반 방향 추정의 대안). 이 시나리오에서 두 개의 GPS 장치를 무빙베이스와 로버라고 합니다.

# 지원 장치

This feature works on F9P devices that support CAN or expose the GPS UART2 port.

The following devices are supported:

Note

Freefly RTK GPS and Holybro H-RTK F9P Rover Lite cannot be used because they do not expose the CAN or UART2 port.
Supported devices are also listed in GPS/Compass > Supported GPS and/or Compass.

이상적으로 두 안테나는 동일한 레벨/수평면에서 동일한 방향으로, 동일한 접지면 크기와 모양을 가지고 있어야합니다 (애플리케이션 노트 (opens new window), 섹션 시스템 레벨 고려 사항).

애플리케이션 노트에는 모듈 사이에 필요한 최소 간격이 명시되어 있지 않습니다 (PX4를 실행하는 테스트 차량에 50cm가 사용되었습니다).
The antennas can be positioned as needed, but the GPS_YAW_OFFSET must be configured: GPS > Configuration > GPS as Yaw/Heading Source.

The UART2 of the GPS devices need to be connected together (TXD2 of the "Moving Base" to RXD2 of the "Rover")
Connect UART1 on each of the GPS to (separate) unused UART's on the autopilot, and configure both of them as GPS with baudrate set to Auto. The mapping is as follows:
- Main GPS = Rover
- Secondary GPS = Moving Base
Set GPS_UBX_MODE to Heading (1)
EKF2_GPS_CTRL parameter bit 3 must be set (see GPS > Configuration > GPS as Yaw/Heading Source).
GPS_YAW_OFFSET may need to be set (see GPS > Configuration > GPS as Yaw/Heading Source).
Reboot and wait until both devices have GPS reception. gps status should then show the Main GPS going into RTK mode, which means the heading angle is available.

Refer to the CAN RTK GPS documentation for each specific device for the setup instructions (such as ARK RTK GPS > Setting Up Moving Baseline & GPS Heading)

Note

If using RTK with a fixed base station the secondary GPS will show the RTK state w.r.t. the base station.