RVSM and HMU testing in CONUS
 

Hello Fellow PPruners,

I am looking for some information on the RVSM Testing in North America (or USA): I understand that there is no more HMU Stations but that the verification of height is performed thanks to ADS-B. I am not sure I understand how this works now..
Aren't there any more stations like in Atlantic City ?
And why do we still have HMU Stations in Europe (LNZ, NTM, GVA,..) ? Why couldnt we do the same with ADS-B In ?

Thanks a million !

Leo