Skywave delay estimation in enhanced loran based on Extended Invariance Principle Weighted Fourier Transform and Relaxation algorithm

A high precision algorithm is proposed to estimate the Enhanced Loran skywave delay, which is based on an Extended Invariance Principle Weighted Fourier transform and Relaxation (EXIP-WRELAX) algorithm. It is an innovation on the application of the skywave interference estimation algorithm in the Enhanced Loran receiver. Compared with existing algorithms, this algorithm has higher accuracy and lower computational complexity. Simulation results show that the proposed algorithm reduces the estimated error accuracy from ∼1000 to 50 m. At the same time, accurate search over the entire frequency domain is avoided, which greatly reduces the computational complexity. The algorithm is also proved by the off-air data.