Don’t be ashamed of the marker buoy system, I still use it until there is an affordable positioning system out there The pros who lack a positioning system still use this method. I know it’s clumsy and a bit difficult to follow down in high current, but it still works. It also gives me a surface reference when I am trying to anchor the boat close to the target site.
In the intermediate until there is a NAV/positioning system, the GPS function of ArduSub works great for surface navigation. It has application if you are making a lot of dives in fairly shallow, calm water so you don’t need to throw out a bunch of buoys. For deep water though…we’re still using the buoy and we’ve landed within 8 feet of a target in 80 feet of water.
I took a stock 3DR GPS module and mounted it on the port side on top of the Fathom X board. I also attached and connected the I2C splitter that came with the Pixhawk to the starboard side so I could have GPS and the depth sensor. When you calibrate your ROV, you will need to disable “Compass 2” (the one on the GPS module) or else you will get a mismatch error.
We’ll be testing this in shallow water this weekend, but the concept of operations will be to launch the vehicle, drive to a point of interest with GPS aiding, commence the dive, and then switch to the video window in QGC for the dive. We’ll see how it works.