This paper presents ZigBee module that is used for ranging in indoor positioning. The system is using thephase shift measurements to determine the distances between user and anchors. The nature of phase shift measurementsis causing the results to be in the range of a single wave length. Thus, as in GNSS measurements, appears the problemwith ambiguity resolution. In satellite positioning this issue is well described but in range-based ZigBee positioning thisproblem needs to be solved. The standard procedure to find the correct values of ambiguities is to search for a combinationof observation equations with smallest RMS. The authors propose a different solution – the Modified AmbiguityFunction Approach (MAFA). It is a method of GNSS carrier phase data processing. In this method, the integer natureof ambiguities is taken into account in the functional model of the adjustment.

DOI: https://doi.org/10.3846/enviro.2017.234