# May the Extensive Farming System of Small Ruminants Be Smart?
## 3 Results
### Wearable Sensors
#### 3.2.2 GPS and Localisation  
The Global Positioning System (GPS) relies on radio signals from specialised satellites that are available during the positioning. GPSs provide data on animal movement and spatial distribution in pastures, including for small ruminants. The animal locations are often combined with relevant environmental information, such as on the vegetation type, topography, proximity to water, and distance to human activities and infrastructures, to evaluate the habitat selection of animals [4; 62; 63]. Monitoring livestock behaviour in extensive grazing systems can assist in managing the animal and its interactions with the environment [48]. Currently, the devices are attached to a collar around the sheep's neck, similar to the bells traditionally used in Alpine farming [16]. [PERSON] et al. [67] reported that GPS sensors on the collar rather than near the mouth and rape position had a low error in the position assignment. This result is positive from the point of view of animal welfare as sheep are grazed, especially on extensive farms, and are accustomed to using leather collars with hanging bells. With a variable weight depending on the manufacturing companies, the tracking technique can be considered non-invasive as it does not influence the natural behaviour of sheep and goats. However, usage is scaled based on the presence of energy: battery life in the field, the lack of wireless data transmission, and the accuracy, interpretation, and contribution of these measurements to decision-making [74]. Some devices have a GPS sensor and a small solar panel for charging the battery. The operation involves the transmission of positions at different intervals depending on the battery charge, with a margin of error. The datasets are analysed using geographic information software. Knowledge of the positions of the paths taken by grazing animals allows one to evaluate an animal's circadian rhythm, assessing whether movement patterns are regular or change over time. It allows one to identify the preferred area on the pasture based on the stopover time and the calving sites and determine when calving begins and whether the offspring survive in the first days after birth [25]. GPS technology also facilitates the study of animal interactions to help determine whether a pasture is overutilised and how access to high or low-quality pasture impacts sheep group dynamics [16; 42]. By combining GPS tracker technology with a long-range wide area network (LoRa-WAN), it is possible to monitor the locations and movements of animals over extensive pastures [9]. The use of RFID proximity collars has been shown to be an efficient way to monitor a large group of animals at a reasonable cost. [PERSON] et al. [43] observed sheep in New Zealand using sensors that logged animal positions; [PERSON] et al. [29] studied three Merino sheep in Patagonia, Chile, equipped with head-mounted 3D activity meters with GPS receivers. Overall, these GPS studies showed that purely positional information about a grazing animal is important for assessing its welfare [46]. [PERSON] et al. [71] showed that the combination of various technologies (infrared cameras, 3D computer vision, and GPS) yields good results in monitoring the position and behaviour of small ruminants with high accuracy. In other studies, GPS collars [75], combined with machine learning [18] or accelerometers and weather stations [54], have been used to detect lambing events, with an accuracy of up to 91%.