Fast Fourier Transform Based Direct Position Determination Method

Time Difference of Arrival (TDOA) systems are used to estimate the position of an electromagnetic emission. These systems estimate the position by using TDOA values of signal pairs received by receivers located at different positions. In practice, TDOA-based position estimation methods use a two-step approach because they are faster. In the first step, the time difference between signal pairs is obtained, and in the second step, the position of the electromagnetic emission is estimated. However, in this method, errors made in the first step are added to the second step, causing the estimation error to grow. In the literature, the Direct Position Determination (DPD) method, which obtains position estimation in a single step using the Maximum Likelihood (ML) approach to overcome this problem, is proposed. The DPD method is shown to perform better than the TDOA method at low signal-to-noise ratios (SNR). However, it is seen that the DPD method, with its high computational complexity, is not practical. In this study, a Fast Fourier Transform (FFT)-based approach is used instead of Fourier Series Coefficients (FSC) used in the DPD method to accelerate the positioning algorithm. Simulation results show that the proposed method has better estimation performance than the TDOA method and approaches the performance of the DPD method. Moreover, it is shown that the proposed method is faster than the DPD method, approaching practical speeds.