We are pleased to inform you that EUROCAE WG-119 “Radar Altimeters” has been created.
Updated MOPS shall address the RA robustness against the existing and planned future RF environment. This future RF environment (refer schematic above) is combining all the following interferences concurrently:

• Interferences at the edges of the RA band (3800-4400MHz) and (4400-5000MHz) including anticipated futures modulations and signal strength;

• Interferences within the RA band (4200-4400MHz) including: other RAs interference on board the a/c, other RAs off board the a/c, WAIC systems and any other system within RA band that are located off board the a/c, WAIC systems and any other system within RA band that are located on board the a/c;

• Out of RA band interferences that could potentially have an indirect effect on the RA due to: level of signal, modulation, potential harmonics, RA antenna potential weakness (susceptibility), RA design potential weakness (resonance).

To meet this goal particular attention should be paid on:

• Operational assumptions (Worst case a/c operational scenarios, worst case RF scenarios…);

• Interferences level assumptions (possible Modulations, Signal Strength, possible bandwidth, antenna pattern…);

• Technical characteristics of RA (Maximum input level of interference the RA equipment has to support, RA Antenna pattern within and outside RA band, RA Noise Floor level, RA chirp bandwidth, IF Bandwidth, Change Rate, Power emissions, Modulations…)

The last but not the least, RA is designed under the highest level of safety requirements. As a consequence a particular attention should also be paid on the definition of appropriate margins. WG-119 will work jointly with RTCA SC-xxx. The current ED-30 and DO-155 are not technically identical; one of the aims of this revision is to align these documents and to develop technically identical documents (ED-30A/DO-155A), which will supersede the current ED-30 and DO-155.