监测动物的位置和接近度可以提供有关行为和活动的有用信息,它可以作为健康和福利指标。然而,全球导航卫星系统(GNSS)等工具成本可能很高,耗电,通常很重,因此在小型反刍动物系统中不适合商业摄取。蓝牙低功耗(BLE)的发展可以为动物监测提供另一种选择,然而,BLE信号强度可以是可变的,并且需要进一步的信息来了解室外环境中信号强度和距离之间的关系,并评估可能在动物场景中影响其解释的因素。包含BLE读取器的专用设备的校准,除了商业BLE信标,在现场环境中进行,以探索信号强度如何随距离变化,并调查这是否受到设备高度的影响,因此,动物行为。从这个校准,开发了距离预测方程,从而可以基于信号强度来估计距读取器的信标距离。然后试用了BLE作为本地化手段,首先使用多点定位方法,使用6个BLE阅读器在围场的5.400平方米区域内定位16个静态信标,随后进行了对绵羊的验证,其中在毗邻围场的1.4公顷范围内对断奶羔羊进行了两种本地化方法的尝试,被九位BLE读者包围。使用来自配备BLE信标和独立GNSS设备的羔羊的1天数据进行验证。校准显示信号强度随着信标与读取器的距离增加而下降,范围缩小,在较低的读取器和信标高度报告的信标比例较早下降。距离预测方程表明,在静态研究中,平均低估了12.13m,在绵羊验证中,平均低估了1.59m。在静态信标定位研究中,多点定位方法产生的平均定位误差为22.02m,而在绵羊验证中,两种方法都产生了相似的平均定位误差-使用中点19.00m和使用多点定位方法23.77m。我们的研究证明了使用BLE技术在户外环境中定位绵羊的技术可行性;然而,这种系统的潜在商业应用将需要BLE范围和精度的改进。
Monitoring animal location and proximity can provide useful information on behaviour and activity, which can act as a health and welfare indicator. However, tools such as global navigation satellite systems (GNSS) can be costly, power-hungry and often heavy, thus not viable for commercial uptake in small ruminant systems. Developments in Bluetooth Low Energy (BLE) could offer another option for animal monitoring, however, BLE signal strength can be variable, and further information is needed to understand the relationship between signal strength and distance in an outdoor environment and assess factors which might affect its interpretation in on-animal scenarios. A calibration of a purpose-built device containing a BLE reader, alongside commercial BLE beacons, was conducted in a field environment to explore how signal strength changed with distance and investigate whether this was affected by device height, and thus animal behaviour. From this calibration, distance prediction equations were developed whereby beacon distance from a reader could be estimated based on signal strength. BLE as a means of
localisation was then trialled, firstly using a multilateration approach to locate 16 static beacons within an ∼5 400 m2 section of paddock using 6 BLE readers, followed by an on-sheep validation where two
localisation approaches were trialled in the
localisation of a weaned lamb within ∼1.4 ha of adjoining paddocks, surrounded by nine BLE readers. Validation was conducted using 1 days\' worth of data from a lamb fitted with both a BLE beacon and separate GNSS device. The calibration showed a decline in signal strength with increasing beacon distance from a reader, with a reduced range and earlier decline in the proportion of beacons reported at lower reader and beacon heights. The distance prediction equations indicated a mean underestimation of 12.13 m within the static study, and mean underestimation of 1.59 m within the on-sheep validation. In the static beacon
localisation study, the multilateration method produced a mean
localisation error of 22.02 m, whilst in the on-sheep validation, similar mean
localisation errors were produced by both methods - 19.00 m using the midpoint and 23.77 m using the multilateration method. Our studies demonstrate the technical feasibility of localising sheep in an outdoor environment using BLE technology; however, potential commercial application of such a system would require improvements in BLE range and accuracy.