Rozylowicz Laurentiu, Bodescu Florian P, Ciocanea Cristiana M, Gavrilidis Athanasios A, Manolache Steluta, Matache Marius L, Miu Iulia V, Moale Ionut C, Nita Andreea, Popescu Viorel D
Center for Environmental Research and Impact Studies, University of Bucharest, Bucharest, Romania.
Multidimension R&D, Bucharest, Romania.
PeerJ. 2019 Jan 31;7:e6362. doi: 10.7717/peerj.6362. eCollection 2019.
Advances in wildlife tracking technology have allowed researchers to understand the spatial ecology of many terrestrial and aquatic animal species. Argos Doppler is a technology that is widely used for wildlife tracking owing to the small size and low weight of the Argos transmitters. This allows them to be fitted to small-bodied species. The longer lifespan of the Argos units in comparison to units outfitted with miniaturized global positioning system (GPS) technology has also recommended their use. In practice, large Argos location errors often occur due to communication conditions such as transmitter settings, local environment, and the behavior of the tracked individual.
Considering the geographic specificity of errors and the lack of benchmark studies in Eastern Europe, the research objectives were: (1) to evaluate the accuracy of Argos Doppler technology under various environmental conditions in Romania, (2) to investigate the effectiveness of straightforward destructive filters for improving Argos Doppler data quality, and (3) to provide guidelines for processing Argos Doppler wildlife monitoring data. The errors associated with Argos locations in four geographic locations in Romania were assessed during static, low-speed and high-speed tests. The effectiveness of the Douglas Argos distance angle filter algorithm was then evaluated to ascertain its effect on the minimization of localization errors.
Argos locations received in the tests had larger associated horizontal errors than those indicated by the operator of the Argos system, including under ideal reception conditions. Positional errors were similar to those obtained in other studies outside of Europe. The errors were anisotropic, with larger longitudinal errors for the vast majority of the data. Errors were mostly related to speed of the Argos transmitter at the time of reception, but other factors such as topographical conditions and orientation of antenna at the time of the transmission also contributed to receiving low-quality data. The Douglas Argos filter successfully excluded the largest errors while retaining a large amount of data when the threshold was set to the local scale (two km).
Filter selection requires knowledge about the movement patterns and behavior of the species of interest, and the parametrization of the selected filter typically requires a trial and error approach. Selecting the proper filter reduces the errors while retaining a large amount of data. However, the post-processed data typically includes large positional errors; thus, we recommend incorporating Argos error metrics (e.g., error ellipse) or use complex modeling approaches when working with filtered data.
野生动物追踪技术的进步使研究人员能够了解许多陆地和水生动物物种的空间生态学。阿戈斯多普勒是一种由于阿戈斯发射器体积小、重量轻而被广泛用于野生动物追踪的技术。这使得它们能够安装在体型较小的物种身上。与配备小型全球定位系统（GPS）技术的设备相比，阿戈斯设备的使用寿命更长，这也促使了它们的使用。在实际应用中，由于诸如发射器设置、当地环境以及被追踪个体的行为等通信条件，经常会出现较大的阿戈斯定位误差。
考虑到误差的地理特异性以及东欧缺乏基准研究，研究目标如下：（1）评估罗马尼亚各种环境条件下阿戈斯多普勒技术的准确性，（2）研究直接破坏性滤波器对提高阿戈斯多普勒数据质量的有效性，（3）提供处理阿戈斯多普勒野生动物监测数据的指南。在静态、低速和高速测试期间，评估了罗马尼亚四个地理位置与阿戈斯定位相关的误差。然后评估了道格拉斯阿戈斯距离角度滤波算法的有效性，以确定其对最小化定位误差的影响。
测试中接收到的阿戈斯定位的相关水平误差比阿戈斯系统操作员指出的误差大，包括在理想接收条件下。位置误差与欧洲以外其他研究中获得的误差相似。误差是各向异性的，绝大多数数据的纵向误差较大。误差主要与接收时阿戈斯发射器的速度有关，但其他因素，如传输时的地形条件和天线方向，也会导致接收低质量数据。当道格拉斯阿戈斯滤波器的阈值设置为局部尺度（两公里）时，它成功排除了最大误差，同时保留了大量数据。
滤波器的选择需要了解目标物种的运动模式和行为，所选滤波器的参数化通常需要反复试验的方法。选择合适的滤波器可以减少误差，同时保留大量数据。然而，后处理数据通常包括较大的位置误差；因此，我们建议在处理滤波后的数据时纳入阿戈斯误差度量（例如，误差椭圆）或使用复杂的建模方法。
