although for various reasons it hasn't yet materialised
basically because the ADSB bandwidth is used up.
multi-lat is interesting, but in reality, again, bandwidth is used up already, even without adding more information to the broadcast. For the Multi-Lat, I dont think anyone wants to be adding more towers at this point.
as noted before, ADSB can handle about 4000 messages per second before it degrades. When we did the trials at Munich, there were upwards of 30 THOUSAND message per second already
There is a direction in using 980 MHZ ADSB for ground ops, and I believe there are a few of these systems in operation...
the 1090 Committees are stuck in limbo, and AIXM is looking at revising the packet content anyways...
In regards to ROT and Wake Cat, the Wake Cat has nothing to do with ARR ROT.
It may be a stretch to say that the Wake Cat has something to do with the DEP queue, and while not ROT, it is a way to optimize the queue and airport throughput on DEP.