Direct Position Determination with Carrier Frequency Estimation of Multiple Unknown Sources Using LEO Satellites

The detection of electromagnetic signals by satellites often uses a two-step method. The proposed direct position determination (DPD) method has improved the accuracy of passive location. However, the DPD method requires the signal carrier frequency as an input parameter, and the carrier frequencies of multiple unknown signals are challenging to measure accurately. In this paper, we propose a DPD method with carrier frequency estimation of multiple unknown sources using low-earth orbit (LEO) satellites, which estimate the carrier frequencies of each source while localizing.