For ship-based deployments, some instruments require actively stabilized platforms to compensate for the ship’s motion, especially rotations around the long axis of the ship (roll), short axis (pitch), and, for some instruments, vertical axis (yaw).
ARM currently employs two types of stabilized platforms: one electrically controlled for lighter instruments that includes yaw control (dubbed RPY for Roll, Pitch, Yaw) and one hydraulic platform with three independently controlled legs for heavier instruments, like the Marine W-Band ARM Cloud Radar (MWACR), (dubbed RPH for Roll, Pitch, Heave [vertical translational motion]).
For a comprehensive report on the purpose, characteristics, and functionality of the RPH hydraulic stabilized platform, see this Report on the Second ARM Mobile Facility (AMF2) Roll, Pitch, and Heave (RPH) Stabilization Platform: Design and Evaluation. For further details of the platform’s electronics, configuration, and performance evaluation, see this Report on the Second ARM Mobile Facility (AMF2) Stabilization Platform: Control Strategy and Implementation.