Calibration of NLOS error for positioning systems

In positioning system NLOS (non-line of sight) errors always cause remarkable positive bias to the estimation of TOA (time of arrival) or TDOA (time difference of arrival) and directly affect range measurement errors. A new method is proposed to calibrate NLOS errors by using the relationship between the mean excess delay and the delay spread measured at a mobile station. The computer simulations showed that the proposed calibration technique effectively reduces the positioning error caused by the urban NLOS environment.