Coverage-Mapping Method Based on a Hardware Model for Mobile-Robot Positioning in Intelligent Spaces

In this paper, we describe a method for relating the precision in phase shift measurements to the navigation areas in which that precision is reached so that a coverage map is built, setting a signal-to-noise ratio (SNR) threshold level that depends on that phase precision. The method brings a novel approach to linking different areas in robotics and is applied to a mobile-robot (MR) local positioning system (LPS) in an intelligent space, where distances are computed from differential phase shift measurements with intensity modulation and direct detection (IMDD) infrared signals. A global model including the parameters of all the parts involved, e. g., optoelectronics, wireless channel, and instrumentation hardware, is developed. Furthermore, based on the model, an analytical expression deduced for the phase shift measurement is used to find the necessary SNR for a desired precision. A complete set of results, applying the coverage cells to a real building covering a path followed by an MR, is shown. The position of the MR can be known, with an accuracy value below 5 cm and tested in a basic rectangular locating cell with dimensions 3.0 m x 2.5 m.