Feasibility Study for Single Platform Airborne FDOA and TDOA Estimation With Unknown Source
Alexander Karlsson · KTH Publication Database DiVA (KTH Royal Institute of Technology) · 2016
Direction of arrival (DOA) estimation is a well studied topic and used in many different applications. Although it is usually based on time-difference-of-arrival (TDOA) of coherent signals, it is sometimes possible to also use frequency-difference-of-arrival (FDOA). By combining TDOA and FDOA a more reliable estimate of the DOA can be obtained. This can be useful in military applications such as reconnaissance and surveillance where the objective is to locate unknown transmitters. It is however not always possible to obtain accurate TDOA and FDOA estimates. In this study the conditions for this are examined for the airborne case when the receivers are on the same aerial vehicle. A method for simulating and estimating TDOAs and FDOAs is also presented. The results are based on simulations with three different signal types and conditions are found for which accurate TDOA and FDOA estimation can be achieved. These conditions are obtained from the Cramér-Rao bounds for TDOA and FDOA. It is shown that FDOA can in some cases yield a higher accuracy in the DOA estimate than what is possible with TDOA.