Finally, Honeywell has a selection of dead reckoning modules (DRM®) that provide positioning data for personnel on foot in environments where GPS data is either unreliable or cannot be used. The DRM® units provide reliable, self-contained positioning data, in a compact, efficient form factor, that can be easily attached and carried by persons on foot. These products are provided as components for integration with other equipment such as RF data links and map displays. The DRM® is a miniature, self-contained, electronic navigation unit that provides the user’s position relative to an initialization point. This is the first commercially available and practical implementation of drift-free dead reckoning navigation for use by personnel on foot. It is specifically designed to supplement GPS receivers during signal outages. Personnel locations can still be know even when GPS is blocked by nearby buildings, heavy foliage, or even inside many structures.