Validation of Real-Time Kinematic (RTK) Devices on Sheep to Detect Grazing Movement Leaders and Social Networks in Merino Ewes

Abstract

Understanding social behaviour in livestock groups requires accurate geo-spatial localisation data over time which is difficult to obtain in the field. Automated on-animal devices may provide a solution. This study introduced an Real-Time-Kinematic Global Navigation Satellite System (RTK-GNSS) localisation device (RTK rover) based on an RTK module manufactured by the company u-blox (Thalwil, Switzerland) that was assembled in a box and harnessed to sheep backs. Testing with 7 sheep across 4 days confirmed RTK rover tracking of sheep movement continuously with accuracy of approximately 20 cm. Individual sheep geo-spatial data were used to observe the sheep that first moved during a grazing period (movement leaders) in the one-hectare test paddock as well as construct social networks. Analysis of the optimum location update rate, with a threshold distance of 20 cm or 30 cm, showed that location sampling at a rate of 1 sample per second for 1 min followed by no samples for 4 min or 9 min, detected social networks as accurately as continuous location measurements at 1 sample every 5 s. The RTK rover acquired precise data on social networks in one sheep flock in an outdoor field environment with sampling strategies identified to extend battery life.

An Information-Theoretic Approach to Detect the Associations of GPS-Tracked Heifers in Pasture

“…The combination of these systems, referred to as multi-GNSS, promises to be beneficial regarding a shorter positioning convergence time [55,56], as well as position accuracy due to the increased number of satellites and the better constellation between satellites and sensors [54,55] after the correction of ambiguities [56]. While solely using multiple GNSSs, the accuracy might stay in the range of meters, utilizing real-time kinematic (RTK) positioning, and differential correction can lower the error in the range of centimeters under perfect conditions [57].…”

“…Investigating the social behavior of Merino Ewes, Keshavarazi et al constructed an RTK-corrected multi-GNSS device named RTK rover that was attached to the animals by using a dog harness [57]. The accuracy of the receiver was determined to be 20 cm, and the researchers compared video observations with GNSS records, concluding that the RTK rover correctly determined the position of animals relative to each other [57].…”

“…Investigating the social behavior of Merino Ewes, Keshavarazi et al constructed an RTK-corrected multi-GNSS device named RTK rover that was attached to the animals by using a dog harness [57]. The accuracy of the receiver was determined to be 20 cm, and the researchers compared video observations with GNSS records, concluding that the RTK rover correctly determined the position of animals relative to each other [57]. Although the usage of this device appears to be not yet practical for continuous recording of animals for a long time, the authors underwent an important step by investigating new technologies for animal monitoring.…”

A Low-Cost GNSS Prototype for Tracking Runners in RTK Mode: Comparison with Running Watch Performance

“…U-blox modules implement this technology and make it available through application boards ready to be integrated in prototypes for almost every kind of positioning-based application [3,4]. High-precision single-frequency in RTK mode has been successfully developed and validated for vehicle applications [5] and non-human tracking [6]. The development of a small and lightweight system for applying the GNSS RTK positioning to running, both from the point of view of the professionalism and the amateurism, can help to describe in a better manner the performance level of athletes.…”

Estimation of Inter-System Biases between BDS-3/GPS/Galileo and Its Application in RTK Positioning

“…As a typical technology of relative positioning, real-time kinematic (RTK) positioning is widely applied in marine navigation, velocity measurements, automatic driving, etc. [11][12][13]. Centimeter-level precision can be achieved when the float ambiguities are correctly fixed to integers [14].…”