Department of Physics, Naval Postgraduate School, Monterey, CA 93943, USA.
Sci Rep. 2016 Jul 21;6:29957. doi: 10.1038/srep29957.
A narrowband MEMS direction finding sensor has been developed based on the mechanically coupled ears of the Ormia Ochracea fly. The sensor consists of two wings coupled at the middle and attached to a substrate using two legs. The sensor operates at its bending resonance frequency and has cosine directional characteristics similar to that of a pressure gradient microphone. Thus, the directional response of the sensor is symmetric about the normal axis making the determination of the direction ambiguous. To overcome this shortcoming two sensors were assembled with a canted angle similar to that employed in radar bearing locators. The outputs of two sensors were processed together allowing direction finding with no requirement of knowing the incident sound pressure level. At the bending resonant frequency of the sensors (1.69 kHz) an output voltage of about 25 V/Pa was measured. The angle uncertainty of the bearing of sound ranged from less than 0.3° close to the normal axis (0°) to 3.4° at the limits of coverage (±60°) based on the 30° canted angle used. These findings indicate the great potential to use dual MEMS direction finding sensor assemblies to locate sound sources with high accuracy.
一种基于橙色奥氏蝇机械耦合耳的窄带 MEMS 测向传感器已经被开发出来。该传感器由两个在中间耦合的翅膀和两个支腿组成，附着在一个基底上。传感器在弯曲共振频率下工作，具有类似于声压梯度麦克风的余弦指向特性。因此，传感器的指向响应关于法线轴是对称的，这使得方向的确定变得模糊。为了克服这个缺点，两个传感器以类似于雷达方位定位器的倾斜角组装在一起。两个传感器的输出一起进行处理，允许在不需要知道入射声压水平的情况下进行测向。在传感器的弯曲共振频率（1.69 kHz）下，测量到的输出电压约为 25 V/Pa。根据使用的 30°倾斜角，声的方位角的不确定度范围从接近法线轴（0°）的小于 0.3°到覆盖范围的极限（±60°）的 3.4°。这些发现表明，使用双 MEMS 测向传感器组件来高精度定位声源具有很大的潜力。
