Precise wireless indoor localization with trilateration based on microwave backscatter

We present two techniques for estimating accurately the position of a mobile base station in industrial environment with Trilateration. By eliminating the need to measure angles, trilateration uses only distance measurements to estimate position, which facilitate the implementation of real-time positioning systems like the Global Positioning System (GPS). Iterative linear least squares and nonlinear least squares estimators are implemented through simulation. We consider the minimization of the squares of errors, where the main difference depends on the linearity of the measurement equation which relates the coordinates to be estimated to the measured distance. The results obtained show that the nonlinear squares technique results in more accurate position estimates than linear least squares. Error distribution functions and histograms in both cases are derived and analysed.