RT_RTK_Attitude Roll, pitch, yaw and accuracy
RT_RTK_Attitude: 140, 32 (0x8C2020 + unit id) (0x320)
Byte 0: Validity
Byte 1: Accuracy
Bytes 2-3: RTK Yaw (degrees)
Bytes 4-5: RTK Pitch (degrees)
Bytes 6-7: RTK Roll (degrees)
RTK Yaw, pitch and roll resolution are degrees/100.
This message is used for attitude calculated from the RTK solution only, with no inertial input.