Ercoline William R, Self Brian P, Matthews Roger S J
Attitude Awareness Laboratory, AFRL/HEP, Veridian Engineering, Brooks AFB, TX 78235-5104, USA.
Aviat Space Environ Med. 2002 Nov;73(11):1053-8.
Helmet-mounted displays (HMDs) allow pilots to view aircraft instrument information while looking to the side, away from the aircraft centerline axis. In that situation, pilots may lose attitude awareness and thus develop spatial disorientation. A secondary concern is the possible effects of visual conflict between the apparent motion of traditional, nose-referenced flight symbology and the off-axis view of the outside world.
Alternative symbologies will provide improved attitude awareness for HMDs when compared with the conventional inside-out symbology now used with head-up displays (HUDs), if the HUD symbology is used on a HMD.
The 9 pilots were presented 48 randomly arranged unusual attitude conditions on a HMD. The three symbologies included: 1) the inside-out representation now used with fixed HUDs, which features a moving horizon and pitch ladder; 2) an outside-in display that depicts a moving aircraft relative to a fixed horizon; and 3) an inside-out novel symbology termed the grapefruit' display (GD). The background scene contained a mix of either a front view orientation or a side view one. Conditions were randomized within and across subjects. Subjective preferences were collected after the completion of all tasks.
Analysis of variance repeated measures design revealed that stick input for the GD was significantly faster with fewer roll reversal errors than either of the other two. The time to recover to straight and level was significantly shorter for the front view orientation than the side view. Of the nine pilots, eight preferred the GD symbology as a method of presenting attitude information on the HMD.
Results suggest the current HUD symbology is not the best way of displaying attitude information on the HMD. Given the conditions of this study, the best way of presenting the pilot with attitude information on the HMD is with the GD symbology.
头盔显示器（HMD）使飞行员在看向一侧、远离飞机中心线轴时能够查看飞机仪表信息。在这种情况下，飞行员可能会失去姿态感知，从而产生空间定向障碍。另一个问题是传统的、以机头为参考的飞行符号的表观运动与外界轴外视图之间视觉冲突的可能影响。
如果在头盔显示器（HMD）上使用平视显示器（HUD）的符号，与现在用于平视显示器（HUD）的传统由内向外符号相比，替代符号将为HMD提供更好的姿态感知。
9名飞行员在HMD上面对48种随机排列的异常姿态情况。三种符号包括：1）现在用于固定平视显示器（HUD）的由内向外表示，其特点是有移动的地平线和俯仰刻度；2）一种由外向内的显示，描绘相对于固定地平线移动的飞机；3）一种由内向外的新型符号，称为“葡萄柚”显示（GD）。背景场景包含前视图方向或侧视图方向的混合。条件在受试者内部和受试者之间随机化。在所有任务完成后收集主观偏好。
方差分析重复测量设计显示，与其他两种符号相比，GD的操纵杆输入明显更快，横滚反转错误更少。前视图方向恢复到直线和水平状态的时间明显短于侧视图方向。在9名飞行员中，8人更喜欢GD符号作为在HMD上呈现姿态信息的方法。
结果表明，当前平视显示器（HUD）的符号不是在头盔显示器（HMD）上显示姿态信息的最佳方式。在本研究的条件下，在HMD上向飞行员呈现姿态信息的最佳方式是使用GD符号。
