To support increased traffic volumes on already congested air routes, reduced vertical separation minima (RVSM) are being introduced globally, increasing demands on the accuracy of aircraft avionics that report altitude.

RVSM is focused on reducing vertical separation minimums from 2000 ft to 1000 ft between FL 290 and FL 410. Height Monitoring Units (HMU), needed to verify the Minimum Aircraft System Performance Specification (MASPS) of aircraft, are found beneath the Upper Air Route (UAR) to ensure that aircraft maintain requested flight levels. ERA's multilateration technologies have been shown to provide the measuring element of a height monitoring unit.

Due to its extreme accuracy and reliability, NEO is able to precisely measure aircraft altitudes in a given UAR through its Height Data Processing System (HDPS). ERA was selected by EUROCONTROL, NATS and Okayama, JCAB to deliver a Height Monitoring Unit within their RVSM program.