An assessment of the direction-finding accuracy of bat biosonar beampatterns.
An assessment of the direction-finding accuracy of bat biosonar beampatterns.
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DOI：
10.1121/1.4940667
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发表时间：
2016-02
期刊：
影响因子：
--
通讯作者：
Uzair S Gilani;R. Müller
中科院分区：
文献类型：
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作者：
Uzair S Gilani;R. Müller
在蝙蝠的生物声纳系统中，发射的声能和接收器灵敏度通过具有多种且通常复杂的几何形状的波束图函数在方向和频率上分布。动物可以利用这种复杂性来根据光谱特征确定传入声音的方向。本研究研究了蝙蝠生物声纳波束方向图如何适合使用给定方向可能的最小估计方差的测量[Cramér-Rao下界（CRLB）]。 CRLB 值是根据来自 330 个单独形状样本、157 个鼻叶（用于发射）和 173 个外耳（耳廓）的数值波束方向图估计值进行估计的。在假设的 60 dB 信噪比下，CRLB 的平均值为 3.9°，这与之前的行为发现相似。各个波束图案中 CRLB 的分布具有正偏斜，表明存在给定波束图案不支持高精度的区域。支持的最高精度是针对高程测向（叶口发射模式除外）。在所调查的主要分类群之间没有发现 CRLB 存在大的、明显的差异（平均值大于 2°），这表明不同的蝙蝠物种可以获得相似的测向信息。
In the biosonar systems of bats, emitted acoustic energy and receiver sensitivity are distributed over direction and frequency through beampattern functions that have diverse and often complicated geometries. This complexity could be used by the animals to determine the direction of incoming sounds based on spectral signatures. The present study has investigated how well bat biosonar beampatterns are suited for direction finding using a measure of the smallest estimator variance that is possible for a given direction [Cramér-Rao lower bound (CRLB)]. CRLB values were estimated for numerical beampattern estimates derived from 330 individual shape samples, 157 noseleaves (used for emission), and 173 outer ears (pinnae). At an assumed 60 dB signal-to-noise ratio, the average value of the CRLB was 3.9°, which is similar to previous behavioral findings. Distribution for the CRLBs in individual beampatterns had a positive skew indicating the existence of regions where a given beampattern does not support a high accuracy. The highest supported accuracies were for direction finding in elevation (with the exception of phyllostomid emission patterns). No large, obvious differences in the CRLB (greater 2° in the mean) were found between the investigated major taxonomic groups, suggesting that different bat species have access to similar direction-finding information.