Direction-of-arrival (DOA) estimation is an important task in microphone array processing and many downstream applications. The steered response power with phase transform (SRP-PHAT) method has been widely adopted for DOA estimation in recent years. However, accurate SRP-PHAT estimation in 3D scenarios requires evaluating steering responses over thousands of candidate directions, severely limiting real-time performance on resource-constrained platforms. This challenge becomes even more critical for planar arrays, which are widely used in robotics due to their structural simplicity. Motivated by the fact that azimuth estimation is usually more reliable than elevation estimation for most arrays, we propose ASAP, an azimuth-priority strip-based search approach to planar microphone array DOA estimation in 3D. In the first stage, ASAP performs coarse-to-fine region contraction within azimuthal strips to lock azimuth angles while retaining multiple maxima through spherical caps. In the second stage, it refines elevation along the great-circle arc between two close candidates. Extensive simulations and real-world experiments validate the efficiency and merits of the proposed method over existing approaches.

翻译：波达方向（DOA）估计是麦克风阵列处理及众多下游应用中的一项重要任务。近年来，相位变换引导响应功率（SRP-PHAT）方法被广泛用于DOA估计。然而，在三维场景中实现精确的SRP-PHAT估计需要评估数千个候选方向的引导响应，这严重限制了其在资源受限平台上的实时性能。对于因结构简单而广泛应用于机器人的平面阵列，这一挑战尤为严峻。鉴于大多数阵列的方位角估计通常比俯仰角估计更可靠，我们提出ASAP——一种面向平面麦克风阵列三维DOA估计的方位优先条带搜索方法。在第一阶段，ASAP在方位角条带内执行由粗到精的区域收缩，通过球冠锁定方位角并保留多个极大值；在第二阶段，沿两个相近候选点之间的大圆弧精确估计俯仰角。大量仿真与真实环境实验验证了所提方法相较于现有方法的效率与优势。