Unmanned Aerial Vehicle Systems in Crop Production

A Compendium

K. R. Krishna

• Publisher: Apple Academic Press
• Year: 2019
• Print ISBN: 9781771887564
• eBook ISBN: 9780429757471
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Science General
• Index: Technology & Engineering

This volume responds to the growing interest in adopting aerial robots (UAVs, or drones) for agricultural crop production, which are revolutionizing farming methods worldwide. The book provides a detailed review of 250 UAVs that examines their usefulness in enhancing profitability, yield, and quality of crop production.

Recent trends indicate an increase in agricultural drone production and use. Millions of dollars have been invested in start-ups that produce agro-drones in the past several years. North America, Europe, China, and the Far East have excelled in offering a large number of UAV models. Some of them are versatile, a few are specific, and many of them are low cost. With so many drone models (over 1200) available, how do farmers and agricultural specialists choose the models best for them?

This compendium examines the most useful drones and provides the pertinent details about each drone, its producer, cost incurred, and its pros and cons. It covers their technical specifications, suitability for various purposes, previous performances in farms, and possible benefits to farmers. It covers fixed-wing drones, fixed-winged (hybrid) VTOL helicopters, multi-copters, tilted-wing drones, etc. The book includes a few drones meant more for military or other purposes (e.g. recreation/fun) but that could be easily modified and adapted for the farming sector. The reviews compare activities among the UAVs, such aerial imagery of crops, ability to provide spectral analyses to collect useful data about a crop's growth patterns, and how they can be used to gauge crop canopy temperature (i.e. water stress index), determine grain maturity, and much more.

CHAPTER 1

Introduction to Unmanned Aerial Vehicle Systems Utilized in Agriculture

ABSTRACT

This chapter introduces the concepts relevant to the use of unmanned aerial vehicles during crop production. Firstly, salient features of UAVs utilized in agriculture are described. Types of UAVs and their classification is briefly mentioned. Discussions cover a wide range of UAVs such as fixed-winged drone aircrafts, autonomous helicopters, fixed-winged VTOL hybrid UAVs, multi-rotor drones for aerial imagery and spraying plant protection chemicals, etc. Parachutes, parafoils, blimps, aerostats, and kites are other types of UAVs with potential to be adopted in farming in a big way. A few examples of successful use of UAVs in farming has been quoted briefly. Fixed-winged drones are efficient in supplying aerial imagery and spectral data about crops. Helicopters and multi-copter drones are useful for close-up surveillance of crops and during spraying pesticides/fungicides. UAVs such as aerostats, blimps, and parafoils are useful in aerial photography, surveillance, spectral analysis of crops, and detecting and reporting disasters. Tethered aerostats are used to collect crop’s phenomics data on a continuous basis. Aerostats are also useful in rural telecommunication networks. Economic aspects of usage of UAVs are highly relevant for farmers, prior to their full-fledged adoption. Some facts about the extent of production of UAVs and forecasts have been listed.

1.1 HISTORICAL ASPECTS OF UNMANNED AERIAL VEHICLE TECHNOLOGY

The unmanned aerial vehicles (UAVs) have found a niche in the agrarian regions of the world. They are: flocking, flying, and at times hovering over the canopies of vast stretches of crops. Their entry into agrarian belts has been delayed compared to their usage in military and other civilian aspects of life. Although belated, now UAVs seem to have simultaneously invaded different agrarian regions of the world. Agricultural UAVs are forecasted to have a very large impact on global crop production methods, the need for labor, inputs such as fertilizers, pesticides, fungicides, herbicides, and irrigation water. UAVs offer aerial images picked from vantage points above the crop canopies, that is, a “bird’s-eye view” plus accurate spectral data for analysis. This aspect was never an easy possibility during past millennia (Krishna, 2018). Agricultural UAVs are among the latest of the techniques appreciated by farmers and agricultural researchers worldwide. These UAVs are expected to revolutionize crop husbandry methods. UAVs are here to flourish in the agrarian regions and offer us advantages for infinite period, in future.

Let us briefly consider the historical facts of UAVs, in general. It seems attempts to develop UAVs began with Nikola Tesla, who described a remote-controlled aircraft. It led to development of “tele-automation” which is crucial for UAV technology (Vroegindeweij et al., 2014). UAVs were first used in military campaign during World War I. Ruston Proctor Aerial Target of 1916 was the first pilotless aircraft (UAV). It was controlled, using Low’s radio control techniques (Talon LPE, 2017). They were first developed in 1916; however, improvement in UAV technology related to military use occurred in the years between World Wars I and II (Nicole, 2015). Keane and Carr (2013) and Newcome (2004) offer reviews about the historical developments of UAVs. They state that development of UAV technology for military is now at least a century old. It seems British Navy in the Mediterranean region used it for the first time to hit enemy position. They launched military UAVs from an aircraft carrier (HMS Argus). Major initiatives to develop, test, evaluate, refine, and deploy UAVs as a defense arsenal occurred in the United States during 1950s and 1960s. It was done under a code name “Red Wagon.” It began with the induction of Ryan Firebees series of military UAVs (Tetrault, 2014; Krishna, 2018). UAVs, therefore, have roots in military establishments of European nations and the United States (Krishna, 2018; Blake, 2017). It seems that development of UAV technology for warfare suffered a kind of stagnation and lack of interest, until it was deployed in a good scale in the Vietnam War during 1960s (Schwing, 2007; Kennedy, 1998). A pilot in the United States Air Force points out that, even as recently as half a decade ago, “UAVs” meant and conjured up idea of warfare, intelligence in battle fields, missile launches to destroy ground force, and air torpedoes. It is not so now. The enthusiasm to opt UAVs for civilian use, particularly in agricultural cropping belts has far surpassed the military importance of UAVs (Jacobsen, 2016; Gago et al., 2015). UAVs were utilized to study weather patterns by the meteorological services of the United States in 1946. During past few decades, UAVs have offered excellent data about general weather conditions, tornadoes, storms, droughts, and floods in vast areas. Incidentally, Krishna (2018) has reviewed and listed several instances that exemplify the shift of focus of UAV technology, from solely military to civilian and agricultural uses, in the recent past. It has been pointed out that, so far, transition from predominantly military usage to agricultural aspects has occurred smoothly without a hitch. At times, it has also occurred in spurts. A few of the major military UAV-producing companies have abruptly shifted their focus. They have refined and modified their erstwhile UAV models to suit agricultural purposes, mainly aerial survey (e.g., R-Bat and Bat by Northrop Grumman Inc.). A few other UAV models have been modified to conduct spectral analysis of crops, procure digital data for precision farming vehicles, and to spray the crops.

Agricultural UAVs have a very short history. It spans for just past one decade. UAVs were introduced into farming zones relatively too recently. Reports suggest that UAVs were being evaluated for their efficacy in offering aerial photography sometime by 2007 (Dobberstein, 2013). UAVs were replacing piloted aircraft in many places. It was attributable to economic and logistical constraints related to human-piloted airplane campaigns. Forecasts done around 2007 suggested that UAVs will spread all through different agrarian belts. UAVs do affect the way crop husbandry procedures are conducted. To a certain extent, UAVs effects are evident. The UAV usage may get accentuated further in farm belts. UAVs have the potential to replace a large section of farm labor involved in scouting, collecting data, applying fertilizers, and spraying plant protection chemicals. This fact has induced large number of start-ups that produce a very wide range of UAV models. Specialized UAV models are also being flooded into the market since 2012–2015 (Krishna, 2018; Ottos, 2014; Bowman, 2015). In the United States, UAV models have crept into the airspace of maize, soybean, and wheat belts of the Northern Great Plains. Farmers in the Plains are promptly testing UAV models and utilizing them since past 3–4 years (United Soybean Board, 2014). Citrus groves in Florida are being surveyed for nutritional and water status and general health using UAVs. UAVs offer spectral data of orchards that can be analyzed to identify the occurrence and spread of weeds and Huanglongbing disease caused by a virus (Lee et al., 2008; Garcia-Ruiz et al., 2013).

The use of UAVs in general civilian and agricultural zones requires a set of few major regulatory guidelines, rules to be followed, registration of the equipment, pilot training, and license for pilot. Each nation seems to have already formulated regulations. For example, Canadian Aviation Agency has its own rules (Fitzpatrick and Burnett, 2014; Redmond, 2014). The Federal Aviation Agency (FAA) of the United States is preparing its own well-discussed and detailed set of rules. The regulations are being prepared since 4–5 years. They were expected to be released for UAV technologists to follow, say, by end of 2016 (Krishna, 2018; Talon LPE, 2016; Dorr, 2014; Precision Farming Dealer, 2015).

Historically, the top few rankings of companies dealing with UAV (in general) and related accessories such as computers and hardware were garnered by those supplying military UAVs. However, now, the interest in military UAVs and demand for them has steadied and plateaued. Therefore, exchequer generated by them now seems to have stagnated for the past few decades. However, during past decade civilian and agricultural uses for UAVs have markedly improved. UAV companies producing small agricultural UAVs and related sensors to suit aerial imagery (visual and thermal) and sprayer equipment have taken the lead. The number of agricultural UAV companies has increased enormously. A recent market report states that UAV companies such as DJI of China, Parrot of France, Microdrones Gmbh of Germany, and 3D Robotics Inc., USA, offer a range of small agricultural UAVs. Similarly, Aeryon and SenseFly produce the popular models such as SkyRanger and eBee, respectively. The above few companies and Pix4D Inc. that produces image processing software are among the top 20 UAV and UAV-related companies (Drone Industry Insights, 2016). The report clearly mentions that ranking of UAV companies fluctuates. During recent times, there is a spurt in production and sales of agricultural UAVs. Therefore, companies dealing with agricultural UAVs top the rankings.

The major focus of this volume is on UAV. However, there are also other means and aerial vehicles that allow spectral analysis of crops from vantage points. It is intended to acquaint and discus about these other aerial vehicles, but only to a certain extent. Parachutes, blimps, balloons, and kites have all been used as UAVs. They are good enough to conduct aerial survey of ground features and agricultural belts. Parachutes were designed and tested by medieval intelligentsia. Sketches of parachutes by Leonardo da Vinci (1452–1519) clearly depict the existence of such contraptions (Bellis, 2017). Faust Vrančić, it seems, demonstrated parachute for the first time by jumping from the tower in Venice in 1617. First actual use of parachute was achieved by a Frenchman, Jean-Pierre Blanchard in 1785. It seems parachute was used to escape from disaster-prone balloons. There are art galleries and museums in European cities showing the use of parachutes during recent history, that is, 1700–1900. By 1890, a few improvements in parachute technology such as “fasteners” avoided any mishaps. Parachutes became easily portable since careful and accurate folding methods were devised. During early part of 20th century, parachutes were regularly used to jump from airplanes and to obtain images of ground features (Bellis, 2017). At present, parachutes with facility for inclusion of sensors, CPU, and even a pilot, if it happens to be semiautonomous parachute (glider), are available. Parachutes have been used to survey large patches of natural vegetation, agrarian regions, and individual farms. Parachutes have offered some excellent visual bandwidth data and multispectral signatures of crops. Parachutes have also been used to conduct regular evaluation of field crops in experimental farms. For example, SUSI 62 (Thamm, 2011) and “Pixy motorized parachute” (Lelong et al., 2016) have been adopted to collect data pertaining to crops. Parachutes have also been used to apply plant protection chemicals, provided, the wind interference is low. Parachutes offer one of the best endurance among aerial robots. They can stay afloat for days above the crop fields. They regularly relay data to ground station.

Now, let us consider a few historical facts about balloons, blimps, and kites used in wars for aerial reconnaissance, espionage, and offensive tactics. Let us list historical facts about these aerial contraptions and their role in agricultural farming. Montgolfier brothers of France were among the earliest to experiment with balloon. They were trying to use them as UAVs. These aerostats were used in warfare. These balloons (UAVs) were used by Austrians during their attack on Italian army during 1849 war. They used balloons to drop and detonate explosives exactly at different locations in Venice city (Talon LPE, 2017).

A search for the meaning of the word “blimp” suggested that, a blimp is a kind of airborne vehicle that levitates from the pressure of lifting gas. Blimps do not contain toughened airframe, unlike airships or Zeppelins (e.g., Hindenburg). Regarding the origin of the word blimp, it is said that in the military vernacular these vehicles are termed “Type B limp bags.” So, the word blimp was derived out of this phrase. Another explanation states that, in 1915, when these air bag-like vehicles were examined, they made a sound whenever the pilots ran fingers over it. They referred it as blimp. A third explanation states that British had blimps in 1918 and Oxford dictionary traces the usage of word blimp to British military in 1916. The word “Zeppelin” was commonly used to refer to blimps and airships. This name is derived from its inventor Ferdinand Count Zeppelin of France.

Kites made using bamboo and silk were flown by Chinese and Japanese some 2000 years ago. In the Far East, kites have been used as part of religious activities since ancient period. Chinese (e.g., Han Hsin, 200 B.C.) used kites in military conquests. They conducted espionage by sending kites above the fort’s walls. Kites were in vogue during medieval period. The British, French, Italian, and Russian armies have adopted kites during World War I (NASA, 2016). Kites were used by the United States Navy during World War II. Samuel Cody, it seems, first drew attention of British military by crossing the “English Channel.” He used kites to drag the boat. The “Cody kite” design is very popular even today (NASA, 2016). It seems, during later years British Army preferred regular blimps (airships).

Reports by kite enthusiasts and agricultural kite researchers point out that “kites” which we intend to deploy above crop fields is indeed a 100-year old technology (Table 1.2). Kites with multiple tails and camera were used to depict the vast destruction caused to San Francisco city due to earthquake of 1906. ...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• About the Author
• Table of Contents
• Abbreviations
• Preface
• Acknowledgments
• 1. Introduction to Unmanned Aerial Vehicle Systems Utilized in Agriculture
• 2. Fixed-Winged Unmanned Aerial Vehicle Systems Utilized in Agriculture
• 3. Helicopter and Multirotor Unmanned Aerial Vehicle Systems Utilized in Agriculture
• 4. Parachutes, Blimps, Balloons, and Kites as Unmanned Aerial Vehicles Useful in Agriculture
• 5. Sensors and Image Processing Computer Software Relevant to Unmanned Aerial Vehicle-Based Technology in Agriculture
• 6. Applications of Unmanned Aerial Vehicle Systems in Agriculture: A Few Examples
• Index