Aircraft Geometric Height Measurement Element (AGHME)
The NAARMO has developed the AGHME system to monitor all aircraft passing through its coverage volume, with the primary aim of supporting estimation of height-keeping performance parameters for the bulk of operations in North American RVSM airspace. The AGHME system does not require that any special monitoring devices be installed on an aircraft in order that it be monitored. It is necessary, however, that the aircraft have an operational Mode S transponder.
All AGHME systems are functionally identical. Hence, an operator wishing to use an AGHME constellation to satisfy monitoring requirements should follow the instructions provided under AGHME monitoring procedures. This will suffice at any AGHME constellation location.
AGHME constellations are located at three sites in the United States and Canada. AGHME locations provides information about these locations and associated availability dates.
ADS-B Out RVSM monitoring - Aircraft equipped with qualified ADS-B Out systems are height-monitored each day during normal operations in US ADS-B rule airspace at RVSM altitudes. Aircraft that are due for periodic monitoring or that must verify performance can fly any day to obtain a monitoring result. Click this link to read more on Monitoring Methods.
The complete source for all operator/aircraft RVSM information is available at RVSM documentation.