# Precision Agriculture: A Remote Sensing Monitoring System Architecture +
## 8 Use Case Study: The DIAS Architecture
### DIAS Architecture  
The DIAS platform follows the architectural design of the proposed remote sensing monitoring system. As presented in Figure 4 the DIAS system is consisted of seven architectural layers. In each layer the most suitable aforementioned technologies are used towards achieving the overall system's efficient performance and reliable operations. The saffron cultivation is a quite demanding and delicate process requiring the deployment of tailor-based technologies and continuous crop monitoring to avoid animal and disease interventions. In the Sensor layer, quadcopter UAVs with thermal, hyperspectral and RGB cameras are being used in cooperation with multiple wireless nodes equipped with various sensors for data collection regarding the crops. Saffron cultivation monitoring requires the study of small sized crops and the notice of minimal crop state variations during each month. To select the desired information UAVs must fly in a certain distance and place for a specific period of time and by using different  
Figure 3: Saffron cultivation yearly stages. Figure 2: Saffron harvesting. position angles. Quadcopter UAVs is considered to be the best choice for saffron monitoring since they have rotary wings, which provide them with the ability of maneuverability, while also flying in low speed. Regarding RGB cameras, they are ideal since saffron cultivation requires the capture of data-images in different weather conditions avoiding inadequate or excessive exposure of the image. Using multispectral or hyperspectral sensors, UAVs can also obtain information related to spectral absorption and reflection of the crops in several bands. This quite useful since the provided information can then be used to calculate vegetation indices and monitor the state of saffron crops based on them. On the other hand, thermal imaging detects specific levels of radiation and translates it into a grayscale image, using brighter and darker shades of heat representation. This ability is also essential in saffron cultivation since the fields are regularly trampled by animals that are not being detected on time in before they cause any damage. The DIAS monitoring system uses different ground and on-leaf sensors to collect useful data for improving the cultivation process. More specifically, environmental humidity and temperature is evaluated since saffron requires specific conditions to prosper. Additionally, the levels of luminosity, leaf-wetness, soil moisture, pH and wind speed are also of great importance. Furthermore, the amounts of nitrogen, phosphorus and potassium in the soil can have a severe impact on the plant's growth, as well as the moisture levels in the soil. The farmer will be able to predict production loss efficiently due to a round knowledge of the saffron fields condition and even intervene with possible treatments to change its course for the better. Regarding the Link and Encapsulation layer, sensor data exchange in the DIAS platform is enabled by the LoRaWAN technology and the IPv6 protocol. LoRa technology offers several advantages. The LoRa physical layer uses ISM bands 868 and 915 MHz--frequencies that are free to use anywhere in the world. In addition, LoRa devices consume very little power making it ideal for battery-powered devices and it can also transmit and receive data for up to 15 km in suburban areas and 5 km in urban areas. Another advantage of LoRa is its high network capacity. In LoRaWAN, a single gateway can accommodate 1000 end-node devices. On the other hand, IPv6 offers large addressing space and has built-in support for network auto-configuration. In the DIAS platform, each sensor node is characterized by its own IP address and uses a power saving scheduling and routing protocol to transmit the collected data to the nearest LoRa Gateway. The information to be exchanged is encrypted before transmission. Each LoRa gateway forwards the information to the according network router for Internet access and data storage to the system' database.