Study of guidance techniques for aerial application of agricultural compounds

Candidate systems were identified for evaluation of suitability in meeting specified accuracy requirements for a swath guidance system in an agriculture aircraft. Further examination reduced the list of potential candidates to a single category, i.e., transponder type systems, for detailed evaluation. Within this category three systems were found which met the basic accuracy requirements of the work statement. The Flying Flagman, the Electronic Flagging and the Raydist Director System. In addition to evaluating the systems against the specified requirements, each system was compared with the other two systems on a relative basis. The conclusions supported by the analyses show the Flying Flagman system to be the most suitable system currently available to meet the requirements

A low-cost remote sensing system for agricultural applications

This research develops a low cost remote sensing system for use in agricultural applications. The important features of the system are that it monitors the near infrared and it incorporates position and attitude measuring equipment allowing for geo-rectified images to be produced without the use of ground control points. The equipment is designed to be hand held and hence requires no structural modification to the aircraft. The portable remote sensing system consists of an inertia measurement unit (IMU), which is accelerometer based, a low-cost GPS device and a small format false colour composite digital camera. The total cost of producing such a system is below GBP 3000, which is far cheaper than equivalent existing systems. The design of the portable remote sensing device has eliminated bore sight misalignment errors from the direct geo-referencing process. A new processing technique has been introduced for the data obtained from these low-cost devices, and it is found that using this technique the image can be matched (overlaid) onto Ordnance Survey Master Maps at an accuracy compatible with precision agriculture requirements. The direct geo-referencing has also been improved by introducing an algorithm capable of correcting oblique images directly. This algorithm alters the pixels value, hence it is advised that image analysis is performed before image georectification. The drawback of this research is that the low-cost GPS device experienced bad checksum errors, which resulted in missing data. The Wide Area Augmented System (WAAS) correction could not be employed because the satellites could not be locked onto whilst flying. The best GPS data were obtained from the Garmin eTrex (15 m kinematic and 2 m static) instruments which have a highsensitivity receiver with good lock on capability. The limitation of this GPS device is the inability to effectively receive the P-Code wavelength, which is needed to gain the best accuracy when undertaking differential GPS processing. Pairing the carrier phase L1 with the pseudorange C/A-Code received, in order to determine the image coordinates by the differential technique, is still under investigation. To improve the position accuracy, it is recommended that a GPS base station should be established near the survey area, instead of using a permanent GPS base station established by the Ordnance Survey

White paper – On the use of LiDAR data at AmeriFlux sites

Our aim is to inform the AmeriFlux community on existing and upcoming LiDAR technologies (atmospheric Doppler or Raman LiDAR often deployed at flux sites are not considered here), how it is currently used at flux sites, and how we believe it could, in the future, further contribute to the AmeriFlux vision. Heterogeneity in vegetation and ground properties at various spatial scales is omnipresent at flux sites, and 3D mapping of canopy, understory, and ground surface can help move the science forward

Real-time nondestructive citrus fruit quality monitoring system: development and laboratory testing

This study reports on the development and laboratory testing of the This study reports on the development and laboratory testing of the nondestructive citrus fruit quality monitoring system.  Prototype system consists of a light detection and ranging (LIDAR) and visible-near infrared spectroscopy sensors installed on an inclined conveyer for real-time fruit size and total soluble solids (TSS) measurement respectively.  Laboratory test results revealed that the developed system is applicable for instantaneous fruit size (R2 = 0.912) and TSS (R2 = 0.677, standard error of prediction = 0.48 °Brix) determination.  Future applications of such system would be in precision farming for in-field orange quality determination during the harvest and for row specific yield mapping and monitoring.    Keywords: LIDAR sensor, visible-near infrared spectroscopy, fruit size, sugar conten

Mass-Market Receiver for Static Positioning: Tests and Statistical Analyses

Nowadays, there are several low cost GPS receivers able to provide both pseudorange and carrier phase measurements in the L1band, that allow to have good realtime performances in outdoor condition. The present paper describes a set of dedicated tests in order to evaluate the positioning accuracy in static conditions. The quality of the pseudorange and the carrier phase measurements let hope for interesting results. The use of such kind of receiver could be extended to a large number of professional applications, like engineering fields: survey, georeferencing, monitoring, cadastral mapping and cadastral road. In this work, the receivers performance is verified considering a single frequency solution trying to fix the phase ambiguity, when possible. Different solutions are defined: code, float and fix solutions. In order to solve the phase ambiguities different methods are considered. Each test performed is statistically analyzed, highlighting the effects of different factors on precision and accurac

Predicting malting barley protein concentration

The preferred grain protein concentration (CP) of malting barley is 10.5-11.0%, but 9.5-11.5% is acceptable. It is a challenge for farmers to achieve this target with crops grown in heterogeneous fields and exposed to fluctuating weather conditions. There are also economic and environmental reasons to balance the supply of nutrients to plant requirements. This forms the basis for precision agriculture, where barley has received limited attention. The key factor for precision agriculture in malting barley is the ability to predict CP from early observations of the crop so as to control a second fertiliser application. This thesis investigates the possibility of predicting malting barley grain CP at an early stage of development and of using a second fertilisation application during growth for total nitrogen (N) adjustment. Three experiments were conducted. The first consisted of eleven field trials (1992-1994) and was used to compare broadcasting/harrowing and combi-drilling for applying full-rate fertiliser at sowing using two types of fertilisers; pure N and one also containing phosphorus (NP). The second experiment consisted of sixteen fertiliser field trials (2001-2003) and was used to examine the possibility of postponing the decision on total N. The third consisted of three evenly fertilised fields (2002-2004). In experiments 2 and 3, canopy reflectance was measured at developmental stages BBCH 32, 45 and 69. Soil macronutrients, organic matter and mechanical composition were analysed in all ex-periments. Malting barley yield was higher when fertiliser was combi-drilled into the soil and when NP fertiliser was used. Grain CP was predicted in the field (R2adj = 0.73) from soil electrical conductivity (SECa), the canopy reflection-based vegetation index (VI) TCARI/OSAVI estimated at BBCH 32 and the sum of daily maximum temperatures during anthesis and grain filling (STS). In the fertilisation trials, CP was predicted (R2adj = 0.83) by sowing day number and the VI TCARI evaluated together with solar angle at measurement. Grain yield was independent, and grain CP almost independent, of whether all fertiliser was applied at sowing or divided between sowing and BBCH 32

Robot-assisted Soil Apparent Electrical Conductivity Measurements in Orchards

Soil apparent electrical conductivity (ECa) is a vital metric in Precision Agriculture and Smart Farming, as it is used for optimal water content management, geological mapping, and yield prediction. Several existing methods seeking to estimate soil electrical conductivity are available, including physical soil sampling, ground sensor installation and monitoring, and the use of sensors that can obtain proximal ECa estimates. However, such methods can be either very laborious and/or too costly for practical use over larger field canopies. Robot-assisted ECa measurements, in contrast, may offer a scalable and cost-effective solution. In this work, we present one such solution that involves a ground mobile robot equipped with a customized and adjustable platform to hold an Electromagnetic Induction (EMI) sensor to perform semi-autonomous and on-demand ECa measurements under various field conditions. The platform is designed to be easily re-configurable in terms of sensor placement; results from testing for traversability and robot-to-sensor interference across multiple case studies help establish appropriate tradeoffs for sensor placement. Further, a developed simulation software package enables rapid and accessible estimation of terrain traversability in relation to desired EMI sensor placement. Extensive experimental evaluation across different fields demonstrates that the obtained robot-assisted ECa measurements are of high linearity compared with the ground truth (data collected manually by a handheld EMI sensor) by scoring more than $90\%$ in Pearson correlation coefficient in both plot measurements and estimated ECa maps generated by kriging interpolation. The proposed robotic solution supports autonomous behavior development in the field since it utilizes the ROS navigation stack along with the RTK GNSS positioning data and features various ranging sensors.Comment: 15 pages, 16 figure

Using multi-frequency electrical conductivity measurement to determine the selective salinity in a two-component salt solution

Received: January 12th, 2023 ; Accepted: April 27th, 2023 ; Published: July 19th, 2023 ; Correspondence: [email protected] technologies can help farmers produce safe, sustainable, high-quality food while contributing to the fight against effects of abiotic and edaphic factors. Due to digitalization, a paradigm shift occurred in agriculture, which boosted sensor technology's rapid development, especially soil sensors. Using sensors and the digital knowledge of soil properties, farmers can better understand the needs of the fields and cultivated plants on a micro-scale, thereby saving resources and putting less strain on our environment. The relative salinity of our soils is an important aspect because of the impact on production costs and yield. The future of site-specific crop production is moving towards a sensor-based on-the-go measurement approach because obtaining important soil characteristics quickly and cheaply is still one of the biggest challenges in precision agriculture today. Measuring soil electrical conductivity (EC) could offer an opportunity to overcome these limitations if the different salt components of soil could be separated by analytical methods. In our study, we present a calibration model based on conductometry with which the selective potassium and calcium content can be determined in the laboratory under controlled conditions. Solutions containing K+ and Ca2+ cations in the concentration determined in the experimental model were mixed and measured by changing the frequency of the measuring current. In this study, measurements proved that a mathematical relationship can be used to describe the relationship between the composition and concentration of the two-component solution, the measurement frequency and the conductivity. The potassium (K) and calcium (Ca) content of the solution can be separated from each other, and a regression calibration curve can be recorded, from which the proportion of potassium and calcium in the given solution can be determined as a function

Methods and Applications of 3D Ground Crop Analysis Using LiDAR Technology: A Survey

Light Detection and Ranging (LiDAR) technology is positioning itself as one of the most effective non-destructive methods to collect accurate information on ground crop fields, as the analysis of the three-dimensional models that can be generated with it allows for quickly measuring several key parameters (such as yield estimations, aboveground biomass, vegetation indexes estimation, perform plant phenotyping, and automatic control of agriculture robots or machinery, among others). In this survey, we systematically analyze 53 research papers published between 2005 and 2022 that involve significant use of the LiDAR technology applied to the three-dimensional analysis of ground crops. Different dimensions are identified for classifying the surveyed papers (including application areas, crop species under study, LiDAR scanner technologies, mounting platform technologies, and the use of additional instrumentation and software tools). From our survey, we draw relevant conclusions about the use of LiDAR technologies, such as identifying a hierarchy of different scanning platforms and their frequency of use as well as establishing the trade-off between the economic costs of deploying LiDAR and the agronomically relevant information that effectively can be acquired. We also conclude that none of the approaches under analysis tackles the problem associated with working with multiple species with the same setup and configuration, which shows the need for instrument calibration and algorithmic fine tuning for an effective application of this technology.Fil: Micheletto, Matías Javier. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro de Investigaciones y Transferencia Golfo San Jorge. Centro de Investigaciones y Transferencia Golfo San Jorge: Sede Caleta Olivia - Santa Cruz | Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia Golfo San Jorge. Centro de Investigaciones y Transferencia Golfo San Jorge: Sede Caleta Olivia - Santa Cruz | Universidad Nacional de la Patagonia "san Juan Bosco". Centro de Investigaciones y Transferencia Golfo San Jorge. Centro de Investigaciones y Transferencia Golfo San Jorge: Sede Caleta Olivia - Santa Cruz; ArgentinaFil: Chesñevar, Carlos Iván. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias e Ingeniería de la Computación. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación. Instituto de Ciencias e Ingeniería de la Computación; ArgentinaFil: Santos, Rodrigo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto de Ciencias e Ingeniería de la Computación. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación. Instituto de Ciencias e Ingeniería de la Computación; Argentina. Universidad Nacional del Sur. Departamento de Ingeniería Eléctrica y de Computadoras; Argentin