Direct position determination (DPD) of multiple known and unknown radio-frequency signals

The common methods for position determination of radio signal emitters (communications, radar) are based on measuring a specified parameter of the signal such as Angle-of-Arrival (AOA) or Time-of-Arrival (TOA). The measured parameters are then used to estimate the transmitter´s location. Since the measurements are done at each station independently, ignoring the constraint that the AOA/TOA estimates at different stations correspond to the same location, it is a sub-optimal position determination method. We propose a technique that uses exactly the same data as the common AOA methods but the position determination is direct and can handle more co-channel signals than the common methods. Although there are many stray parameters, only two-dimensional search is required for a planar geometry. The technique provides a natural solution to the measurements-sources association problem that is encountered in AOA based systems and outperforms the AOA methods for unknown as well as known signal waveforms.