The Cramér-Rao bound (CRB) for direction of arrival (DOA) estimation exploiting both auto-correlation and cross-correlation information within multiple frequencies of the received array signals is derived. It provides a tighter bound than the existing CRB for the dual-frequency scenario. For the multiple frequencies, it is much lower than its dual-frequency counterpart, and also exists for a greater number of sources, thereby validating that exploiting multiple frequency pairs can improve both estimation accuracy and target resolvability.

中文翻译：

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利用多个频率对进行 DOA 估计的 Cramér-Rao 界

推导出利用接收阵列信号的多个频率内的自相关和互相关信息来估计到达方向 (DOA) 的 Cramér-Rao 界限 (CRB)。它为双频场景提供了比现有 CRB 更严格的界限。对于多频，它远低于其双频对应物，并且存在于更多的源中，从而验证了利用多频对可以提高估计精度和目标可分辨性。