Indicating target position and pointing out target position in darkness – Comparison between using GPS and verbal reference

It is likely that individual soldiers in the future will be equipped with some form of digital support that includes navigation devices where directions and positions to own units and to threats can appear. Previous experiments in daylight have shown high precision when target indication was performed with a GPS with an electronic map (e.g. Hellgren, Johansson, Oskarsson, & Svensson, 2012; Oskarsson, Johansson, Svensson, Hellgren, & Allberg, 2013). To investigate the possibilities to support military units with GPS solutions for indicating target positions and pointing out targets in darkness with a night vision device, a night-time experiment was performed. Ten officers attending a night-time operations course for instructors participated in the experiment. A Garmin GPSmap 62 stc with a digital map was used. The participants used the GPS to indicate targets on the map that were visible in the terrain, and to point out target positions in the terrain that were displayed on the map. The participants also performed these tasks with conventional verbal target indication based on reference points. Because of limitations in access to participants, only 5 participants could perform the target indication task and 5 participants the pointing out target position task. Therefore, only descriptive analyses could be performed. To collect more information about pros and cons of using a GPS in darkness, a group discussion with all 18 officers attending the course was performed. Also, for further investigation all officers answered three spatial tests that were used in previous experiments. The results showed that the precision of indicating target position and pointing out targets was approximately equal whether the tasks were performed with GPS or verbally with reference points. However, according to the subjective ratings, assessing both bearing and distance was rated as more difficult when the GPS was used. It took longer time to perform the tasks with GPS compared to verbal reference points, in particular pointing out targets which took about three times longer when the participants received target information on the GPS. It should, however, be noted that the participants had no experience of using a GPS for these tasks, whereas they had much experience of using verbal reference points. The fact that the precision with the GPS was approximately equivalent to the precision with verbal reference points is a promising result in respect of using a GPS for these tasks. PTSOT is the spatial test that showed the highest relation with performance in the experiment, which is in line with previous results (Hellgren et al., 2012; Oskarsson et al., 2013). However, due to few participants and also some loss of data, these results should be interpreted with caution. The group discussions provided several important viewpoints on design and usage of a GPS in darkness. For example that the device should be compatible with other systems, have large buttons so it can be used with gloves in cold weather, and that it should have a compass and filtering functions to control the amount of displayed information. These viewpoints are valuable, e.g. for potential requirements specification of a GPS, but also for requirements specifications of other similar soldier systems.