Agriculture

The application of Supercam UAV in the agriculture gives the means to:

1. Create the horizontal and cartographic control survey;
2. Exercise the monitoring of plantlife by vegetation;
3. Provide the control over the execution of technological operations to prevent unauthorized activities.

Generation of cartographic control survey and monitoring the execution of series of technological operations.

The operation of UAV requires the photo camera and geodetic receiver for high accuracy to exercise the flight over agricultural lands and the aerial photography (hereinafter the airborne imagery).

Completion of the aerial survey work result in the generation of:

• accurately georeferenced orthomosaic;
• digital elevation model.

With the help of orthomosaic, fields and different objects get their contour, including such hard places as wood plots, ravines, brooks, driveways, roads, electric grid towers, badger holes, etc. In addition, the orthomosaic serves for the automated computing of areas, object perimeters, distances between any points lying and located on the orthomosaic.

Further processing utilizes the Digital Elevation Model that serves to give the terrain formation, the slope mapping, directions of slopes exposure, the water flow directions (water runoff).

The agricultural company may apply the entire data generated from the airborne imagery in the number of ways:

1. Review all fields on the Orthomosaic; define the supplementary use of land where possible to increase the seeding (sowing) area, or determine where the land area should be reduced on the contrary, where the excavation should be done and the driveways might be cancelled in case of emergency, etc. In other words, how to manage the planning of agricultural lands.
2. If the flights have been exercised amid the technological performance, it facilitates in the imposition of control over the procession of such performance, exercised before the aircraft sortie (e.g. the harrowing area, sowing area (by germination), sowing gaps, uneven sowing plots, sowing overstock (high density of sowing), land parcels where the sowing has not been performed. Furthermore, the application of UAV provides the opportunity to check almost every operation that had been done before the aerial photography. In addition, there is an option to determine the factual area for harvesting and tilling of plowing.
3. Contours received for agricultural lands and fields might be utilized for uploading onto the navigators of agricultural machinery to facilitate performance at night, drive around the obstacles, maintain the field borders with 20-50 cm accuracy, along with the application of systems for parallel driving.
4. Tethered drone might relay the RTK corrections into the vast area at the time of agricultural performance within such area, thus, making the requirement for the construction of relay masts obsolete. At the same time, it keeps the opportunity to carry the on-line video shooting while controlling the performance of mechanizers and mitigating risks of thievery and embezzlement.
5. The generation of the actual field areas and distances between objects facilitates the sustainable planning of all resources (the gasoline, fertilizers, chemical crop protection products, scheduling of the technological performance, etc.). Additionally, there is the opportunity for suitable control over the actual spending of resources and updating internal regulations that prescribe the write-off rates).
6. Besides the aforementioned, the orthomosaic might be applied in registering of land parcels in the state cadastre.
7. Terrain has the significant impact on the crop yield in the agriculture. Pursuant to the actual information about terrain the agricultural companies and farm entrepreneurs might perform the counter-erosion and moisture preservation works, in that from simple change of the direction in technological operations to the soil slitting and slopes strengthening. In addition, the data on terrain have a great importance in the estimation of fertilization and chemical crop protection rates, as well as when analyzing areas of a poor crop development.

Observation of the crop development by vegetation and performance of technological operations

Application of UAV with multispectral (hyperspectral) camera to exercise the flight over the agricultural lands and multispectral imagery. Multispectral (hyperspectral) cameras to observe the crop condition mainly operate in the spectral range of 400 to 1000 µm. The image received in the multispectral imagery is generated in the discrete data channels, which might be as broad so as narrowband, however the object’s specter is not replicated.

With the application of hyperspectral camera, the image is generated in the narrow spectral bands, simultaneously on the whole range fixed by the camera, thus giving the spectral parameter of the object in entire band. The aforementioned imagery results in:

• Ortho-transformed images as per the respective spectral channel with the accurate georeference;
• Building of Index Maps utilizes the ortho-transformed images. The former are images of the brightness values per each pixel, which is computed with the application of arithmetic operations on the brightness values of every pixel from different spectral bands in accordance with the coordinates.

Index Maps are built for various vegetation indices which contain the valuable information on the crops condition. They provide selection of zones with different crop condition inside the agricultural field.

Common indices like NDVI reflect the relative condition of plants on a scale from healthy to stressful, although they do not give the answer as to what might be the cause of such stress. Other indices (SIPI, MCARI/MTVI2, TGI, ARI, etc.) describe the impact of stress factors group and might be applied to determine the causes of the crop stress. In addition, the function of such indices lies in the formation of spatial zones that prescribe:

• the distribution of herbicides to achieve the optimal effect;
• calculation to prescribe the rates and the distribution of fertilizers to increase the crop yield and quality of agricultural plants;
• execution of control over the performance of technological operations which are: the soil refinement and preparation, herbicide care and treatment, etc.;
• the quality assessment of crop sprout upon melting of snow, determination of the sowing zones;
• assessment of crop maturation and planning of harvest works with formulation of sequence;
• execution of the crop yield forecasting to give the estimate before the harvesting commences; 
• further opportunities.

Vegetation index values generated to perform, e.g. nitrogen fertilization, reflect the particular relative amount of nitrogen, i.e. per each land parcel of the field relative of other parcels. With vegetation index that is not supplied with data from the ground surveying it would be impossible to determine the prescribed rate in the performance of nitrogen fertilization. However, if the brightness value of pixel on the index map is compared with prescribed rate of fertilization resulting from the ground surveying, then the outcome from the application of mathematical calculation algorithms will be the accurate map of prescribed amount in nitrogen fertilization according to numerous zones inside the agricultural field. This is the approach that enables the generation of maps for differentiated application of fertilizers, herbicides, etc., with significant reduction in time and financial costs spent on the agro-chemical assessment and increase of their accuracy.

Effective management of the agricultural company might be improved with the modern application of UAV and medium resolution space monitoring data, that freely available (the Landsat 8 data, Sentinel). The information received every first or second week allows observing changes in crop vegetation and reduce the number of UAV flights down to 3-5 sorties per season. In addition, it brings the additional benefit to use the archived spectral space images for the better understanding of various issues at stake.

Provided that a photo camera might be integrated with a multispectral camera for simultaneous application on UAV, the entire aforementioned information might be used per each operational flight. Thus, all data might be obtained and compared in required dynamics.