Traditionally, the direction of arrival (DOA) estimation usually employs homogeneous antenna arrays consisting of many identical antennas. This paper proposes a new technique of DOA estimation by using a heterogeneous array which has many elements with each element pointing to a different direction from others. A general expression of the manifold for planar heterogeneous array is derived. Then, a polarized MUSIC (Pol-MUSIC) method for unknown polarizations is proposed. One advantage of this Pol-MUSIC method is that it can obtain the DOA of signals with any unknown polarizations while no search of the polarizations is required. The proposed method is verified by simulation, and its performance is analyzed. The heterogeneous array is a polarization-sensitive array though it has one channel at each point of spatial sampling. This provides favorable conditions for simplifying the systems.
2. Wang, M., X. Ma, and S. Yan, "An autocalibration algorithm for uniform circular array with unknown mutual coupling," IEEE Antennas Wireless Propag. Lett., Vol. 15, 12-15, 2016.
3. Searle, S., "Disambiguation of interferometric DOA estimates in vehicular passive radar," IET Radar, Sonar & Navigation, Vol. 12, No. 1, 64-73, Jan. 2018.
4. Yang, M., J. Ding, B. Chen, and X. Yuan, "A multiscale sparse array of spatially spread electromagnetic-vector-sensors for direction finding and polarization estimation," IEEE Access, Vol. 6, 9807-9818, Jan. 2018.
5. He, J., Z. Zhang, T. Shu, and W. Yu, "Direction finding of multiple partially polarized signals with a nested cross-diople array," IEEE Antennas Wireless Propag. Lett., Vol. 6, 1679-1682, Feb. 2017.
6. Wong, K. T., Y. Song, C. J. Fulton, S. Khan, and W.-Y. Tam, "Electrically “long” dipoles in a collocated/orthogonal triad — For direction finding and polarization estimation," IEEE Trans. Antennas Propag., Vol. 65, No. 11, 6057-6067, Nov. 2017.
7. Meloling, J. H., J. W. Wockway, and M. P. Daly, "A vector-sensing antenna system, a highfrequency, vector-sensing array based on the two-port loop antenna element," IEEE Antenna & Propagation Magazine, 57-63, Dec. 2016.
8. Erthel, Y., "HF radio direction finding operating on a heterogeneous array: Principle and experimental validation," Radio Science, Vol. 39, No. 1, 1-16, 2004.
9. Muller, R., S. Lutz, and R. Lorch, "A noel circular direction finding antenna array for unknown polariztion," Proc. 7th Eur. Conf. Antennas Propag. (EuCAP), 1514-1518, Gothenburg, Sweden, Apr. 2013.
10. Loy, T. and S. W. Lee, Antenna Handbook, New York, Chapman & Hall, 1993.
11. Weiss, A. J. and B. Friedlander, "Analysis of a signal estimation algorithm for diversely polarized arrays," IEEE Transactions on Signal Processing, Vol. 41, No. 8, 2628-2638, Aug. 1993.
12. Friedlander, B., "Antenna array manifolds for high-resolution direction finding," IEEE Transactions on Signal Processing, Vol. 66, No. 4, 923-932, Nov. 2017.
13. Schmidt, "Multiple emitter location and signal parameter estimation," IEEE Trans. Antennas Propag., Vol. 34, No. 3, 276-280, Mar. 1986.