For many applications relative position information is critical. One particular case is the prevention of compressed air breathing accidents in operations with low visibility. Here, separation of first responders in an unknown and dangerous en- vironment could yield a fatal outcome. The goal of this work is to introduce technology that assists firefighters in situations with no visibility to locate team members. Due to the lack of pre-installed infrastructure, a relative ad-hoc localization scheme without the need for in place infrastructure is required. We propose a three- dimensional ultra-wideband based scheme and show a functional prototype with integrated transceivers combining both, two-way ranging range finding and phase-difference of arrival direction finding. Further, we show a potential architecture for integration in firefighter equipment such as helmet and mask utilizing augmented reality technology. Through multiple experiments we could show, that in the given laboratory setup direction estimation with an accuracy of 20° and position finding with an accuracy of 30 cm is possible with the proposed approach.