Methods: Twelve participants who are blind and twelve age-matched sighted controls participated in the study. Comparisons are made for route-guidance performance between use of updated, real-time route instructions (system-aided condition) and a system-unaided (memory-based condition) where the same instructions were only provided in advance of route travel. The sighted controls (who navigated under normal visual perception but used the system for route guidance) represents a best-case comparison benchmark with the BVI participants who used the system.

Results: Results across all three test measures provide compelling behavioral evidence that blind navigators receiving real-time verbal information from the MagNav system performed route travel faster (navigation time), more accurately (fewer errors in reaching the destination), and more confidently (fewer requests for bystander assistance) compared to conditions where the same route information was only available to them in advance of travel. In addition, no statistically-reliable differences were observed for any measure in the system-aided conditions between the BVI and sighted participants. Post-test survey results corroborate the empirical findings, further supporting the efficacy of the MagNav system.

Discussion: This research provides compelling quantitative/qualitative evidence showing the utility of an infrastructure-free, low-memory demand navigation system for supporting route-guidance through complex indoor environments and supports the theory that functionally equivalent navigation performance is possible when access to real-time environmental information is available, irrespective of visual status.  

Implications for Designers and Practitioners:  Findings provide insight for the importance of developers of accessible navigation systems to employ interfaces that minimize memory demands.

Keywords: indoor navigation system; blind travel; nonvisual navigation; speech-based interfaces

Citation: Giudice, N. A., Whalen, W. E., Riehle, T. H., Anderson, S. M., & Doore, S. A. (2019). Evaluation of an Accessible, Real-Time, and Infrastructure-Free Indoor Navigation System by Users Who Are Blind in the Mall of America. Journal of Visual Impairment & Blindness. Advance online publication: 

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Indoor navigation technology is needed to support seamless mobility for the visually impaired. This paper describes the construction and evaluation of an inertial dead reckoning navigation system that provides real-time auditory guidance along mapped routes. Inertial dead reckoning is a navigation technique coupling step counting together with heading estimation to compute changes in position at each step. The research described here outlines the development and evaluation of a novel navigation system that utilizes information from the mapped route to limit the problematic error accumulation inherent in traditional dead reckoning approaches. The prototype system consists of a wireless inertial sensor unit, placed at the users’ hip, which streams readings to a smartphone processing a navigation algorithm. Pilot human trials were conducted assessing system efficacy by studying route-following performance with blind and sighted subjects using the navigation system with real-time guidance, versus offline verbal directions.

Citation:

Riehle, T. H., Anderson, S. M., Lichter, P. A., Whalen, W.E., & Giudice, N. A. (2013). Indoor inertial waypoint navigation for the blind. Proceedings of the 35th annual IEEE Engineering in Medicine and Biology Conference (EMBC’13, Vol. 2013, pp. 5187-5190).

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