Remote Sensing

Technical specification:

wavelength range 450 nm-950 nm, spectral resolution 8 nm, 125 spectral bands, image resolution 50 x 50 pixels, spatial resolution (at 20 m flying height) 20 x 20 cm.

Application:

The camera captures hyperspectral images in visible and near infrared region of the electromagnetic spectrum. From these images spectral reflectance data can be extracted. 

Spectral data is used to estimate plant biophysical (e.g. biomass, leaf area index) and biochemical (e.g. chlorophyll, nitrogen) traits, to monitor vegetation health (e.g. water stress, diseases), and to map invasive plants (e.g. Lupinus polyphyllus in natural grasslands).

Technical specification:

weight (including batteries) – 7.5 kg, max. payload – 2.5 kg, max. speed – 8 m/s, max. altitude – 100 m, max. safe flight time – 20 min, GNSS system – real time kinematic, includes auto-pilot with planned mission.

Application:

The Unmanned Aerial System (UAS) for the Cubert camera, applied for implementation of high precision guided flights.

Technical specification: RTK-DGPS, including UMTS modem, which is the predominantly applied configuration. Both receivers have 120 channels (60 satellites on 2 frequencies, GPS, GLONASS, Galileo, BeiDou), spatial accuracy of RTK DGPS measurements is <1 cm, degree of protection IP68.

Application: The system is used to measure the accurate position of points as well as for setting out experimental plots or grasslands during data collection (e.g. drone flights).

Technical specification: Beam divergence – 0.23 mrad (FWHM), wavelength – 1550 nm, spatial resolution 0.8 mm – 50 mm (at 10 m distance), scan rate – 1 000 000 points per second, scan angle – 360^o horizontal and 290^o vertical.

Application:  Used to generate 3-dimenstional point clouds in high resolution to derive plant properties like crop height, crop density and species composition.

Technical specification:

Sequoia sensor captures normal RGB (red, green, blue) images (16 Megapixel) and four specific spectral bands: Green (530-570nm), Red (640-680nm), Red Edge (730-740nm), Near Infrared (770-810nm). The sensor is attached to a DJI Phantom III drone and camera calibration is achieved automatically by a sunshine sensor (on the top).

Application:

Multispectral images can be used in general for classification and calculation of vegetation indices. The most common vegetation index is NDVI (normalized difference vegetation index). NDVI provides information about the vegetation by calculating the difference between near-infrared (strong reflection by vegetation) and red light (strong absorption by vegetation). This helps to detect land use changes, to observe plant growth (yield, quality) and health (identification of diseases and weeds).

Example of an NDVI-image (experiment BOEL2020 in Neu-Eichenberg, 2018):

Technical specification: Consumer grade quadcopter drone, flight time ~20 min, sensor: FC300S 12-megapixel RGB camera (F/2.8, 94°, 3.61 mm focal length), spatial resolution of 3D model at 50 m flight height approx. 2 cm.

Application: Used for RGB imaging for point cloud generation with structure from motion (SFM) method and for generation of 3D models of plant canopies to determine plant height. Plant height can be used to model above ground biomass (AGB).

Technical specification: Consumer grade quadcopter drone, flight time approx. 30 min., sensor: FC300S 12-megapixel RGB camera (F/2.8, 94°, 3.61 mm focal length), spatial resolution of 3D model at 50 m flight height approx. 2 cm.

Application: Used for RGB imaging for point cloud generation with structure from motion (SFM) method, for generation of 3D models of plant canopies for plant height determination (input for modelling the above ground biomass), and a platform for multispectral sensor Parrot SEQUOIA.

Technical specification: fisheye lens, focal length – 15 mm (digital), Light intensity: 2.8.

Application: Used for landscape photography, canopy closure and clumping measurements. Can be used for leaf and index measurements in crops and agroforestry systems.