Performance Capabilities of UWB Location and Tracking Systems

The theoretical and practical performance limits of a 2-D ultra-wideband impulse-radio localization and tracking system operating in the far field are studied, with estimates of location being based on time-difference-of-arrival (TDOA) measurements. Performance is evaluated in the presence of errors in both the TDOA measurements and the sensor locations. The performance of both optimal (maximum-likelihood) and suboptimal location estimation algorithms are studied and compared with the Cramer-Rao lower bound on the variance of unbiased TDOA location estimates. A novel weighted total-least-squares algorithm is introduced that compensates for errors in sensor positions compared with a widely used weighted least-squares approach.