Waterhorse Thanks, that does surprise me somewhat. I'm not aware of any work going on at the moment on SBAS lower than LPV-200/CAT I minima. Even the Dual Freq. Multi-Constellation SBAS SARPS aimed only at CAT I, and they were approved in Nov 2020 by the ICAO Nav Systems Panel, and will hopefully be incorporated by State Letter later this year.
Avionics built to those SARPs should be coming on line in around 2027.
Frankfurt have just got their GBAS/GLS GAST-C running to CAT II last year, and All-Weather Ops/LVO world is all looking to GAST-D GBAS for CAT III.