Error mechanisms in an RF-based indoor positioning system

An RF-based indoor precise positioning system being developed for fire fighters is discussed in this paper. The paper will discuss system level overview of the RF prototype and will discuss the NLOS field tests and indoor positioning results using this RF prototype. The position estimation algorithm used is based on Time Difference of Arrival (TDOA) for a multicarrier signal. An error budget for such an RF-based indoor positioning system is presented in this paper with more insight to the sources of errors. Multipath and NLOS conditions indoors are well known error sources but there also exists another not so well known but major sources of error which are due to dielectric properties of the building materials. Basic simulations are presented to better understand the effect of the dielectric properties of building materials on indoor position estimates.