I’d like to ask about the possibility of integrating an external INS and DVL system with the Navigator board. I have reviewed the parameters available in ArduSub 4.5.6 (stable) via the BlueOS autopilot interface. While I noticed options to specify yaw, position, and velocity sources using the EK3_SRC**** parameters, I did not find a parameter that directly allows selection of an external IMU (for example, INS_USE does not appear to support this).
Could you please clarify whether it is possible to fully replace the onboard INS with an external system? If so, I would appreciate any recommendations you might have for compatible INS and DVL sensors, as well as any guidance or documentation on how to proceed with the integration.
As I understand it ArduPilot’s External AHRS functionality (accessible via AHRS_EKF_TYPE) allows either fully replacing the autopilot’s EKF in favour of an external estimator, or (depending on the backend) just using an external setup as a sensor set (in which case it seems the IMU would need to be included in EAHRS_SENSORS, likely with relevant ExternalNav values set in the EK3_SRC parameters).
I’m aware WaterLinked’s DVL offerings include an AHRS, so could be a candidate for developing a new EAHRS backend to support using that (and/or the sensors in it). I imagine other high end systems would also include them.
