Application of vector sensor array in DOA estimation for low angle tracking

Abstract

In this paper, we propose low angle tracking using vector sensor array, which has an advantage to track the target regardless of reflection coefficient. In previous estimation scheme without vector sensor array, it is needed to examine the effect of reflection coefficient and is required to search the solution to prevent failure of tracking under the worst reflection coefficient. To solve the problem, the previous scheme uses frequency diversity. However, frequency diversity scheme has some drawbacks such as limited frequency, unbias estimation, iterative method. Now, we propose polarization diversity scheme applied under every reflection coefficient. To obtain polarization diversity, we need vector sensor array antenna. In general, vector sensor consists of three dipole antennas and three loop antennas. Since there exists just two correlated signals at low angle tracking, we can get enough diversity to decompose direct signal and specular signal by only using two dipole antennas orthogonal to impinging electromagnetic wave. Through performance comparison between polarization diversity and frequency diversity, we demonstrate the superiority of vector sensor array.