2 research outputs found
Semi-Automated Signal Surveying Using Smartphones and Floorplans
Location fingerprinting locates devices based on pattern matching signal observations to a pre-defined signal map. This
paper introduces a technique to enable fast signal map creation given a dedicated surveyor with a smartphone and floorplan. Our
technique (PFSurvey) uses accelerometer, gyroscope and magnetometer data to estimate the surveyor’s trajectory post-hoc using
Simultaneous Localisation and Mapping and particle filtering to incorporate a building floorplan. We demonstrate conventional methods
can fail to recover the survey path robustly and determine the room unambiguously. To counter this we use a novel loop closure
detection method based on magnetic field signals and propose to incorporate the magnetic loop closures and straight-line constraints
into the filtering process to ensure robust trajectory recovery. We show this allows room ambiguities to be resolved.
An entire building can be surveyed by the proposed system in minutes rather than days. We evaluate in a large office space and
compare to state-of-the-art approaches. We achieve trajectories within 1.1 m of the ground truth 90% of the time. Output signal maps
well approximate those built from conventional, laborious manual survey. We also demonstrate that the signal maps built by PFSurvey
provide similar or even better positioning performance than the manual signal maps