We examine the performance of the Direct Position Determination (DPD) approach in the presence of model errors and multipath propagation. DPD is a method that was recently introduced . We have demonstrated that DPD out-performs the conventional location methods (AOA/TOA) under Line-of-Sight (LoS) conditions. The conventional approaches are based on measuring specified parameters, such as Angle or Time of Arrival (AOA/TOA) at each base station and these measurements are then used to estimate the transmitter's location. The conventional approaches are sub-optimal since the measurements at distinct base stations are independent and ignore the constraint that all measurements must correspond to the same location. Using exactly the same data, DPD provides an accurate and natural solution to the measurements-sources association problem that is encountered in AOA and TOA systems. Moreover, in the presence of multipath, DPD provides a better location estimate.