Will your solution work with existing RadarBox hardware ? Or is it too early to ask that question ?
I for one hope so!
Well the only people who can answer that - AirNav - have yet to comment, but I'm sure they will agree that you simply can't do MLat without precise, synchronised timing data from the ground stations involved.
I understand from those who know about these things that the current RadarBox hardware/firmware can't provide this data. While it may be possible to expose precise internal RadarBox timing data via a firmware upgrade, that still leaves the issue of synchronisation.
AirNav have disparaged the PlanePlotter method of doing this via a reference ADS-B aircraft, so clearly they aren't planning to do it that way, and as far as I can see the only other alternative is an architecture that involves all ground stations having access to an external source of synchronised time data.
I think we can rule out atomic clocks inside RadarBox, so that only leaves GPS time as a feasible solution (as with commercial MLat systems).
At the very least, then, I think we're looking at a GPS timer add-on for RadarBox, if not a completely new RadarBox. If I'm wrong, doubtless AirNav will tell us in due course.