# Ensuring Agricultural Sustainability through Remote Sensing in the Era of Agriculture 5.0
## 4 Sensors
### Remotely Piloted Aircrafts (RPAs)
Figure 6: Vegetation index (VIs) maps generated through Parrot Sequoia (a multispectral camera) and Yuneec CGOET (a thermal sensor) mounted on Yuneec Typhoon H hexacopter RPA. (**A**) Crop area studied. (**B**) Map of “chlorophyll a” content based on NDRE. (**C**) Map for vegetation status generated based on NDVI. (**D**) Thermal map established using Yuneec CGOET. (Images facilitated by MC Biodrone). Likewise, it is also important to consider regional and national regulations for operating RPAs, although agricultural applications of RPAs do not invoke substantial risks for people. Government bodies are trying to cope with such regulations, but there is plenty of room for growth. In Europe, the European Union Aviation Safety Agency (EASA) presented legislative framework: \"Easy Access Rules for Unmanned Aircraft Systems\" (Regulations (EU) 2019/947 and (EU) 2019/945), in 2019, for RPA operations and it went into effect from 31 December 2020 [138]. The three principal categories established under this legislation are presented in Table 3. Safety of people, security, privacy, and data protection were the principal parameters considered for establishing these regulations. Nevertheless, most \begin{table}
\begin{tabular}{c c} \hline \hline
**RPA Application Area** & **Reference** \\ \hline Crop growth and monitoring & [7,108–111] \\ Crop scouting & [7,112] \\ Disease detection & [113–116] \\ Bird pest surveillance & [117,118] \\ Irrigation and fertilization & [111,112,115,116,119–124] \\ Soil and field analysis & [7,108,112,125] \\ Weeds management & [112,116,120,126] \\ Crop harvest & [112,127,128] \\ Crop insurance & [112,114,116] \\ Mechanical pollination & [7,116,129,130] \\ Forestry & [131–135] \\ Livestock & [112,114,116,120,130,136,137] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: A summary of a few representative studies for principal agricultural applications of RPAs. (The purpose of citing these references is impartial and is not confined to these studies only). Figure 7: A set of field zones recommended for treatment based on the vegetation indices (VIs) maps, generated using a parrot sequuola and Yuneec CGOET mounted on a Yuneec Typhoon H hexacopter RPA for olive crops (image facilitated by MCBiodrone). countries are struggling to establish standard regulations, and this requires urgent attention. A general list of RPA laws and regulations can be consulted in [139]. This new era is of the Internet of Drones (IoD), where a fleet of drones is deployed, controlled through a ground station server (GSS) via a wireless channel, to harvest the desired data. Currently, research is being undertaken to explore these possibilities for remote areas, where there is no Internet connection. For example, a recent study reported on the possibility of using a cellular network for this purpose [140]. An interesting study by [PERSON] and [PERSON] [141] on the use of RPAs in smart agriculture, based on IoT, is highly recommended, where the possibilities of this novel technology with their practical examples are discussed. Similarly, novel applications of RPAs can also enrich RS technologies; for example, very recently, an RPA was used as a mobile gateway for a wireless sensor network (WSN), establishing a 24-m flying height and a 25-m antenna coverage provided maximum node density [142]. In the same way, the benefits of drone centimeter-scale multispectral imagery were investigated in sugar beet crop to improve the assessment of foliar and canopy parameters; five important structural and biochemical plant traits were reported, highlighting the importance of drone imagery for centimeter-scale characterization [4]. RPAs are already used for capturing videos and photos under specific flight plans, as such, setting an RPA as a node for a WSN is an efficient way to fully benefit from this RS tool. Despite the appeal of IoD, security may be a recurring issue in upcoming years; large companies are already at the brink of this issue.