Statistical theory of the effects of radio location system design parameters on the positioning performance

This paper provides an asymptotic performance evaluation of network based or multilateral radio location estimators that use the time of arrival (TOA) and/or the angle of arrival (AOA) measurements of the signals travelling from a mobile station (MS) to a set of fixed stations (FSs) to estimate the MS´s position. The analysis is based on the Cramer-Rao lower bound (CRLB) and the maximum likelihood theory, and takes into account the effects of the system design parameters as well as the effects of biased measurements, which can result for example from hardware calibration errors or multipath effects, including the lack of line of sight. Explicit formulas that provide a clear relationship between the various system design parameters and the positioning accuracy are derived and discussed. Finally, the theory is verified with numerical simulations.