Emender: Signal filter for trilateration based indoor localisation

Various applications of indoor localisation (e.g. tracking firemen in a burning building, or navigation for the blind) require accurate location estimates. A common indoor localisation approach using commodity mobile phones is to perform trilateration with distance estimates derived from the strength of radio signals, however, they can vary wildly especially indoors. We propose a simple filtering technique to exclude measurements which adversely effect localisation accuracy. Through experimentation in a real building, across state of the art geometries and filtering techniques, our proposed filter shows an increase in accuracy by at least 30% and decrease the time taken to estimate the location by an order of magnitude.