We are building a sea glider! Due to the requirements of our mission, the UUV (Unmanned Underwater Vehicle) can not be tethered nor controlled remotely. Therefore, I was looking for an auto pilot solutions and found Navigator Flight Controller.
In the official video from Blue Robotics explaining Navigator Flight Controller, they say it is possible to build a glider using the Navigator Flight Controller. However, according to the official documentation of ArduSub, tethering and Topside Computer is required.
Does ArduSub Navigator Flight Controller can be used without tethering nor the topside computer? I am thinking maybe I can make a server or utilize another Pi on UUV that function as Topside Computer (or maybe with APRS)? Is there a better solution? I need the UUV to make its own path planning with pre given waypoints. Is there any other solution to this outside of ArduSub? (like PX4?)
Hi @UVEECSoftware -
The Navigator could be used with a glider, and has indeed been used to power a swarm of AUVs from Woods Hole!
However, the ArduSub firmware was not used - while it does support untethered missions with a source of position information (like a DVL) this is not likely practical for your glider application. Users are developing their own autopilot software, and using the Navigator for what it is - a host PCB to motion sensors and PWM output channels. ArduSub and ArduRover actually run within a docker container inside BlueOS - there is no microcontroller on the Navigator!
Check out this thread for some ideas on how to proceed.
Best of luck!
Is there any alternative way for position information then using Doppler Velocity? I am thinking I could dead reckon using IMU and speedometer (It would be very inaccurate though…) or SLAM using Computer Vision or Sonar(It would be very hard because there aren’t many anomalies to recognize).
Hi David -
Acoustic solutions are going to give you the best accuracy with minimal effort - besides DVL solutions, you may check out USBL solutions like the ROVL and WaterLinked UGPS.
Both of those solutions rely on keeping the object being located in range, and generally communicating with it over its tether…
The IMU used on the Navigator is nowhere near accurate enough for integrating it’s measurements over time to give a good estimate of position - this dead-end comes up often unfortunately. For a glider, keeping track of tilt angle and the change in depth may give a rough idea of travel, but this wouldn’t capture motion due to currents in the ocean (which are hard to turn off!) Most AUVs use a combination of this orientation/depth sensing and a DVL for velocity estimates.
I’m eager to see what’s possible in the future with visual SLAM solutions, but am not aware of anything that’s available for the ArduSub platform currently!
Hi @tony-white ,
We are using DVL in our vehicle.Is it possible to do waypoint navigation using DVL without tether? Does vehicle moves untethered once plan is uploaded ? I am using Navigator board with Rasp pi. May i know any reference or well known autopilot software to start with.
Hi @Raj -
Yes, the DVL can be used without a tether for Auto missions. You would trigger the mission to start via WiFi with the vehicle at the surface, but the DVL locked on to the bottom. You can see details in the integration guide.