The Canadian Soldier Information Requirements Technology Demonstration (SIREQ TD) soldier modernization research and development program has conducted experiments to help determine the types and amount of information needed to support wayfinding across a range of terrain environments, the most effective display modality for providing the information (visual, auditory or tactile) that will minimize conflict with other infantry tasks, and to optimize interface design. In this study, seven different visual helmet-mounted display (HMD) designs were developed based on soldier feedback from previous studies. The displays and an in-service compass condition were contrasted to investigate how the visual HMD interfaces influenced navigation performance. Displays varied with respect to their information content, frame of reference, point of view, and display features. Twelve male infantry soldiers used all eight experimental conditions to locate bearings to waypoints. From a constant location, participants were required to face waypoints presented at offset bearings of 25, 65, and 120 degrees. Performance measures included time to identify waypoints, accuracy, and head misdirection errors. Subjective measures of performance included ratings of ease of use, acceptance for land navigation, and mental demand. Comments were collected to identify likes, dislikes and possible improvements required for HMDs. Results underlined the potential performance enhancement of GPS-based navigation with HMDs, the requirement for explicit directional information, the desirability of both analog and digital information, the performance benefits of an egocentric frame of reference, the merit of a forward field of view, and the desirability of a guide to help landmark. Implications for the information requirements and human factors design of HMDs for land-based navigational tasks are discussed.
Two frames of reference (exocentric and egocentric) and two points of view (first-person and second-person) were contrasted in two experiments to measure their effect on wayfinding performance. Twelve male infantry soldiers used three helmet-mounted display designs (second-person exocentric, second-person egocentric, first-person egocentric) to locate bearings to waypoints. From a constant location, participants were required to face waypoints presented at offset bearings of 25°, 65° and 125°. The egocentric display supported faster performance times than the exocentric display, significantly faster at the largest offset. Faster times were attributed to fewer head misdirection errors and better display compatibility with expectations of spatial orientation. The second-person display supported significantly faster performance times than the first-person display at all offset levels. However, the time differences were not attributed to accuracy or head misdirection errors. Other display features, such as amount of information or field of view may have contributed to the differences. There were no qualitative differences between displays for ease of use, acceptance for land navigation, or mental demand. Implications for the design of helmet-mounted displays for land-based navigational tasks are discussed.