L-shape 2-dimensional arrival angle estimation with propagator method

It is known that the computational load of the propagator method (PM) can be significantly smaller, e.g., one or two orders, than those of MUSIC and ESPRIT because the PM does not require any eigenvalue decomposition (EVD) of the cross-correlation matrix and singular value decomposition (SVD) of the received data. However, the PM has non-negligible drawbacks such as (1) a requirement of pair matching between the 2D azimuth and elevation angle estimation and (2) an estimation failure problem when elevation angles are between 70 and 90 degrees. The paper aims to remove these problems in the PM without additional computational load. The paper employs an L-shaped array because the parallel shape used in the PM may cause the aforesaid problems. Simulation results verify that a PM with an L-shaped configuration can remove these problems and improve the performance of the PM significantly, e.g., 5 dB in signal-to-noise ratio for the parameters used.