So the main limitation here is not related to BR/WL technology. The current solution will already provide distance and bearing to target, which you could follow by manual use of onboard propulsion systems. You could most likely also interface this info with your electronic chart system of choice.
But in order to automatically “follow sub”, you will need a DP-capable vessel, most importantly when it comes to truster configuration, but also sensor inputs and onboard control system. This is highly complex and costly, and as @SDI points out you can’t easily retrofit existing boats. Even a very basic boat would need, for DP 0, at least the following:
- Sufficient thrusters for 3 DOF (i.e. bow & stern thruster + main prop or 2 main props + bow thruster)
- Computer capable of running the control software
- Human Machine Interface (Could maybe run on the same computer as above, but is normally separated)
- GPS for position reference (pref. Differential)
- A very good heading indicator (pref. Gyro Compass but Fluxgate or similar could also be used)
- A Motion Reference Unit or IMU in order to compensate for ships movements on GPS
And if you want to offer this boat for charter, you would most likely be asked to provide redundancy of all these components.
Having said that, bearing in mind the recent crisis in O&G, and all the new developments happening in offshore wind and aquaculture, asset owners have become much more cost conscious, so there might be room for a tiny inspection vessel using a DP0 / WL / BROV2 combo. Or they might just continue to press prices with current shipowners.