Vector sensor arrays in DOA estimation for the low angle tracking

In this paper, we propose a new direction-of-arrival (DOA) scheme using a vector sensor array for the low-angle tracking environment that has the interference problem between the direct path and specular path. For the two-ray multipath signals with the angular difference less than a fraction of the beamwidth, previous algorithms such as 3-D beamspace domain maximum likelihood (3-D BDML) works well unless the phase difference between the two rays is 180deg or the magnitude of reflection coefficient is close to 1. Our proposed polarization diversity scheme based on the vector sensor array does not have such limitations on the phase difference or reflection coefficient. Furthermore, the proposed scheme shows better performance than frequency diversity methods even using a smaller number of snapshots.