Helmet-Mounted Displays: - USAARL - The - U.S. Army

Introductory Overview 5
Figure 1.2. The AH-64 Integrated Helmet and
Display Sighting System (IHADSS).
Currently, the Army is developing the RAH-66 Comanche
reconnaissance helicopter. This aircraft will utilize a partially overlapped
biocular HMD, known as the Helmet Integrated Display Sight System
(HIDSS) (Figure 1.3). It consists of a pilot retained unit (PRU) and an
aircraft retained unit (ARU). The PRU is the basic helmet with visor
assembly. The ARU is a front piece consisting of two image sources and
optical relays attached to a mounting bracket (Figure 1.4). The HIDSS
development and validation phase design, which uses two miniature, 1inch,
CRTs as image sources, provides a 30º (V) by 52º (H) field-of-view
(FOV) with a 17º overlap region. However, miniature displays based on
flat panel (FP) technologies [e.g., liquid crystal (LC) and
electroluminescence (EL)] will very likely replace the CRTs in subsequent
program phases.