hey, sounds interesting at least….
a good Idea might be to look at industry standard packages like the Ixsea octans or phins package and offload the specs from that. As a rule of thumb, people here don’t really like change, so a plug n play replacement is prob best idea and matching spec of existing systems. (This is because if you are writing a tender application, you need to specify a survey spread that is consistent with established practise and if you are the ROV supervisor you don’t want to have to spend time changing out equipment from job to job).
What sort of resolution and drift can you achieve at the moment, are you looking at a high-quality survey-grade system or a low-cost, low quality system? There are cheaper alternatives like the FOG from Tritech. Don’t know anything about it’s performance.
If you are looking for buyers and answer to 11. a) If you have a good product, consider approaching someone like sub-atlantic for OEM supply? but by n large you want to have a pressure housing for your gear so that the system can be mobbed/demobbed from system to system without having to loose time on preparations. RS232 is a good protocol if you have a large work-class with fibre optic mux and it’s easy to read with a laptop for diagnostics, but people are happy with 485 or even ethernet protocols. USB 2 is emerging recently.