ABSTRACT Acoustic localisation technology has been widely tested and applied for passive acoustic monitoring and ecological research, however, hardware costs of commercially available devices limit scalability. Furthermore, few studies have explored its use with low-density arrays. We present a low-cost, custom-designed hardware and software system termed ‘CARACAL’ that is able to extract and localise weak acoustic signals. The key to this is the use of four microphones on each logger, allowing for phase-based measurements and the ability to enhance signal-to-noise ratio through beamforming. As a proof of concept, we test the functionality of the CARACAL system by conducting a gunshot localisation experiment and demonstrate animal call detection and localisation from a lion predation event. Results show the system could locate gunshots with an average accuracy of 33.2 ± 15.3 m within an array of 7 stations 500 m apart. When applied to animal call positioning, we show long range (> 1 km) localisation of three different species’ calls, Cape buffalo, chacma baboon and spotted hyaena. With a cost of approximately £150 per unit, the CARACAL system provides a cost-effective solution for acoustic localisation over large areas. The system is open source and can be customised to suit a variety of wildlife research applications.

中文翻译：

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CARACAL：用于野生动物研究和保护的多功能被动声学监测工具

摘要 声学定位技术已被广泛测试并应用于被动声学监测和生态研究，然而，商用设备的硬件成本限制了可扩展性。此外，很少有研究探讨其在低密度阵列中的使用。我们提出了一种称为“CARACAL”的低成本、定制设计的硬件和软件系统，它能够提取和定位微弱的声学信号。关键是在每个记录器上使用四个麦克风，允许进行基于相位的测量，并能够通过波束成形提高信噪比。作为概念证明，我们通过进行枪声定位实验来测试 CARACAL 系统的功能，并演示狮子捕食事件中的动物叫声检测和定位。结果表明，该系统可以在相距 500 m 的 7 个站点的阵列中以 33.2 ± 15.3 m 的平均精度定位枪声。当应用于动物叫声定位时，我们展示了三种不同物种叫声的远距离（> 1 公里）定位，水牛角、狒狒和斑鬣狗。CARACAL 系统的成本约为每台 150 英镑，为大面积的声学定位提供了具有成本效益的解决方案。该系统是开源的，可以定制以适应各种野生动物研究应用。CARACAL 系统为大面积的声学定位提供了一种经济高效的解决方案。该系统是开源的，可以定制以适应各种野生动物研究应用。CARACAL 系统为大面积的声学定位提供了一种经济高效的解决方案。该系统是开源的，可以定制以适应各种野生动物研究应用。