Sources with large power differences are very common, especially in complex electromagnetic environments. Classical DOA estimation methods suffer from performance degradation in terms of resolution when dealing with sources that have large power differences. In this paper, we propose an improved DOA algorithm to increase the resolution performance in resolving such sources. The proposed method takes advantage of diagonal loading and demonstrates that the invariant property of noise subspace still holds after diagonal loading is performed. We also find that the Cramer–Rao bound of the weak source can be affected by the power of the strong source, and this has not been noted before. The Cramer–Rao bound of the weak source deteriorates as the power of the strong source increases. Numerical results indicate that the improved algorithm increases the probability of resolution while maintaining the estimation accuracy and computational complexity.

中文翻译：

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功率差异较大的信号源的DOA估计

功率差异很大的源非常普遍，尤其是在复杂的电磁环境中。当处理功率差异较大的源时，传统的DOA估计方法的分辨率会降低性能。在本文中，我们提出了一种改进的DOA算法，以提高解决此类源的分辨率性能。所提出的方法利用了对角线加载的优势，并证明了在进行对角线加载后，噪声子空间的不变性仍然成立。我们还发现，弱源的Cramer-Rao边界可能受到强源的力量的影响，而这在以前没有被注意到。弱源的Cramer-Rao界随着强源的功率增加而恶化。