Overview of Agri-business for Small Unmanned Airships

9th International Airship Convention, Ashford, 2012

Market Paper

Overview of Agri-business and Forestry Market for small unmanned airships in Latin America

Adrian Peña Cervantes1, Victor Xavier Enriquez Champutiz2 and Adrian Yair Peña Sosa

1Tecnavix, Mexico City, Mexico 2GNC Principal Researcher, CIDFAE, Ambato, Ecuador

4Instituto Tecnológico de Veracruz, Veracruz, Mexico

Abstract

Many concepts have been proposed in recent years among UAS (Unmanned Aerial Systems) Latin American researchers in the area of small unmanned airship for use in agri-business and forestry industry, but very few projects have reached production status yet. One reason is the inherent complexity of most UAS concepts, which in turn drives costs and development time. Other reason is the lack for legal framework to integrate these vehicles to national airspace. The paper authors have conducted small unmanned airship R&D programs in Mexico and Ecuador and reached a substantial experience facing these and other interesting facts and have also through its operation reached a substantial knowledge of agri-business and forestry requirements along Latin-America. This paper offers a study of the Agri-business and forestry Latin-American market for small unmanned airships operations as well provides airship manufacturers with an overview of potential and promising applications in the region (Figure 1).

Fig.1: Small unmanned airship concept in an agriculture field deployment example.

Paper Peña, Enriquez and Peña

9th International Airship Convention, Ashford, 2012 2

1 INTRODUCTION Latin America is the source of many processed agricultural products that consumers in the US, Canada and Europe purchase along the year. During the next few years it is expected that Mexico will be shipping even more avocados, table grapes, and citrus fruit to these markets. Food safety and public health at those markets is a concern with food grown in Mexico and South America. There is a broad scientific consensus that less-resilient agricultural production areas will suffer the most, as temperatures rise further, for example in semitropical and tropical latitudes, and as already dry regions face even drier conditions. [1] Associated to market development it is expected an increase in global demand that is going to be coupled with limitations of supply resulting from scarcity of natural resources like land and water. This gap between supply and demand dictates that those resources need to be used more effectively. Among other reasons this is why capacity of Mexican and Latin American agriculture system to continue providing adequate supplies for food depends in large part on the implementation of new and available technologies. In the past, the majority of increases in the food supply have been possible by better agricultural and farm management practices, farm equipment and machinery, the use of chemical fertilizers and pesticides and more recently by land management. It is now when a mature solution can be offered to the agri-business market employing remote sensing technologies through the use of unmanned aerial systems.

The incorporation of UAS (Unmanned Aerial Systems) to agri-business will allow better practices in crop production, forestry, livestock, fisheries, marketing and much more. Some of their remote sensing activities can also help to adapt to climate change. UAS can take the visual assessment of key soil, state and plant performance indicators of soil quality, presented on a scorecard. With the exception of soil texture, the soil indicators are dynamic indicators, capable of changing under different management regimes and land-use pressures. Being sensitive to change, they are useful early warning indicators of changes in soil condition and as such provide an effective monitoring tool. Small unmanned airships are believed to become a viable decision-support tool for agro-business and forestry communities in Latin America. 2 AGRI-BUSINESSES – MARKET SIZE AND OPPORTUNITIES FOR SMALL UNMANNED AIRSHIPS Agriculture is one of the world’s largest industries, it spans a wide variety of businesses relating to or supporting the cultivation of plants, forestry, fisheries and agriculture. The agribusiness sector has seen impressive growth in recent years, with current revenues in excess of more than $70bn. It looks likely to remain so for the foreseeable future. Rising demand for food together with increases in grain prices and in the area planted have contributed to the overall upward trend.



As we stated above, complex and rapidly-changing agri-business environment requires data that is clear, consistent and collected in or near real time, with consequent requirements for implementation and management of master data and business intelligence strategies. Food producers in Latin American countries need to progress from producing and exporting commodities to adding value and increasing productivity through sustainable processing and manufacturing. Some of the most important aspects related to technology and value addition include: product development, quality and productivity, upgrading enterprises by introducing land and soil management as well as sustainable technological solutions for remote sensing activities. Adding new technology as Unmanned Aerial Systems to this sector also will create ecologically sustainable means of production with regard to the use of water, energy, chemicals and other inputs. [2] There are many platforms available for Unmanned Aerial Systems operations in agri-business activities, some of them more effective than others in certain applications, but unfortunately most of these systems represent a prohibitive cost for most of the small farm and agri-business communities in Latin America. As specialists on the field of unmanned aerial systems we have conducted evaluations during the past 6 years with different platforms for use in agri-business, but the most promising so far for Latin American region seem to be the small unmanned airships because of the next features:

• Low financial outlay and less sophisticated payload requirements (when compared to military and manned aircraft)

• They can be operated under an easier training program for forestry and farm operators.

• They provide potential economic savings and environmental benefits with less fuel consumption, less greenhouse gas emission, and less disruptive noise than for manned aircraft.

• They represent one of the most growing technology tools in remote perception techniques to identify spectral features that are related to water stress, nutrient deficiency, pest infestation and invasive weeds among many other biophysical characteristics.

• The small unmanned airships can bridge the gap between what can be measured by satellites and what is measured at static ground-based, research stations. They are easy to transport, relatively simple to deploy in forest or remote geographic areas as well as easy to launch and recover by on-field operators and agro-forestry specialists. They do not need specialized airfields to conduct flights for photogrammetry and soil analysis.

• Small unmanned airship imagery can complement space-borne imagery in case the latter is not accurate enough or not timely available. Using these kinds of UAS will solve the problem of satellite imagery availability in cloudy conditions in particular



Though many nations have strong unmanned aerial systems (UAS) aspirations, the availability of funds reflects the actual market revenue. Economical and practical UAS platforms must be conceptualized to become integrated to important civilian applications as those we describe in this paper in the agri-business or forestry industry. Lighter-than-air technology can lead the way to integrate economical and affordable solutions for agri-business in developing nations because of innovative advances in automation, Machine vision systems, fabrics and energy management. Recently, we have found that Small unmanned airships can operate with a better deployable operational concept for forestry applications (Figure 2). The opportunities for these UAS in Mexico are very interesting because of the need to update constantly the cartography and vegetation index along the country [3].

Fig.2: Small unmanned airship concept in a forest

deployment example. 3 THE SMALL UNMANNED AIRSHIP DESIGN

Our group has worked in the research and development of Small Unmanned Airships and Unmanned Aerial Systems

(UAS) during the last years in Mexico, Ecuador and Spain in order to provide highly dependable flight operations for the agri-business market in Latin America. As mentioned before, for photogrammetry purposes, the UAS must fly at different altitudes ranging from 0 – 9000 feet above sea level and the technical characteristics of the small unmanned airships are planned as follows:

• Test bed platforms versions ranging 7.8 m – 14m long, 3.0m equipped with 4 control rudders in a ``X shape'' configuration, shown in the figure 3.

• 2 electric motors for power plant as main thrusters providing a maximum speed 45 km/h, decreasing in wind gusts to 25 km/h.

• Flight endurance: 1- 2 hours with 25Km/h cruising speed.

• Maximum available payload prospected for 8 kg (18 lb).

• Two envelopes in the airship hull body. Inner envelope works as pressure-resistant gas helium bag.

• Semi rigid configuration with outer envelope engineered to maintain rigidity necessary for the integration of an optional solar cell array, gondola, stern thruster and rudders in the airship.

• Flight range according to electrical propulsion system (25Km/hr cruise speed) and autopilot capabilities is calculated for 5Km (3 Miles).



Fig. 3: Control rudders in a “X shape” configuration. Photo courtesy of the CIDFAE’s digital archives The propulsion is provided by a group of electric brushless motors (2 motors) attached to each side of the gondola below the center line of the airship and controlled by a dedicated DSP controller module that takes part of the GN & C design. A third electrical motor will be installed in the stern portion of the hull to provide Yaw control under specific maneuvers at low speeds. This motor will be driven by the GN & C system as well as the other power plant equipment and will have a control algorithm defined under software simulations and energy management. The power for electric engines is supplied by a bank of Lithium-Polymer batteries (14.8V 4-6 cells 1600mAh X 2) carried at the gondola’s compartment with 1250W maximum electric consumption for each motor as well as associated wiring with low current waste cables along the entire electrical system.

The propeller (14” x 7”) and motors are protected by a plastic ducted fence mounted at the end of a bar, which rotates driven by a servomotor and a gear system to provide plurality of controllable pitch thrust vector, in order to ascend, descend or gain speed in level flight. The mechanical characteristics of proposed power plant with an internal combustion engine version can be shown in the following figure (Figure 4):

Fig. 4: Power plant mounted on the gondola with a controllable pitch thrust vector mechanism. Photo courtesy of the CIDFAE’s digital archives 3.1 Advances in Autonomous GN & C (Guidance, Navigation and Control) design The GN & C (Guidance, Navigation and Control) system provides an autopilot capability to the small unmanned airship, so that its flight path meets the high-level objectives commanded by the forestry and agriculture operators. Figure 5 shows the scheme of the proposed autopilot system framework.



Fig. 5: Scheme of the Autopilot System Framework. The onboard GN & C (guidance, navigation and control) system will work autonomously to perform station keeping in the presence of varying winds and rising/falling atmospheric density. The GNC is under construction and designed under a R&D program starting with the creation of control algorithms for the unmanned airship in accordance to efficient operational qualities for agro-forestry operators and portable Ground Control Stations. These control algorithms are under test employing dynamic simulations through MATLAB – SIMULINK software. Some of the simulations activities are the following: • Dynamics of the aircraft • Guidance and navigation • Control System • external disturbances (wind, etc ...)

3.2 The PID Controllers for GN & C operation The autopilot system has a decision making concept based in PID (Proportional–Integral–Derivative) control loops. This control concept is under test to provide station-keeping, altitude-hold, direction-hold, velocity-hold, and trajectory-hold for the small unmanned airship under design. Figure 6 shows an example of PID’s closed feedback loop operation.

Fig. 6: Example of a PID Closed feedback loop for operation of elevator control. A PID is the most commonly used feedback controller. It calculates an "error" value as the difference between a measured process variable and a desired set-point. For our autopilot design the PID controllers attempt to minimize the error by adjusting the process control inputs. [4] As mentioned previously, a final goal of our GN & C work is to develop an Autopilot system with PID feedback loop controllers. At present, use of the PID’s in our flights is limited to simulation in Mathlab and Simulink software because a development plan of a technical demonstrator is under preparation.



A block diagram of the proposed PID feedback controller concept is presented in the next figure (Figure 7)

Fig. 7: Block diagram of proposed PID feedback control loop in the GN & C System. 3.3 Advances in Data Link – RF Modem The Small Unmanned Airship missions require the use of a dependable data link to control and command the unmanned GN & C (Guidance, Navigation and Control) system. A second data link will be installed on-board to down-link the real-time hyper spectral camera, as well an optional gyro-stabilized video streaming payload. According to general operational terms, the Data Link will operate mainly in the line-of-sight of the unmanned airship and in continuous presence of radio coverage. The knowledge of all flying parameters (down-linked to the control station by telemetry) is essential to ensure the appropriate handling of the airship. In addition, when automatic phases of flight are conducted, the pilot must be able to take over direct control of the unmanned airship during take-off and landing stages as well as in the

case of unexpected or emergency situations along the mission path with radio coverage availability. An outside line-of-sight operation or radio coverage lost strategy will relay to the autopilot’s GNC (Guidance, Navigation and Control) system to autonomous command the airship for a “back home” maneuver and tracking the aircraft position in real time under emergency RF signal beacons. This will help the operators in the GCS (Ground Control Station) to track and maintain command of the aircraft under different emergency conditions. 3.4 Ground Control Station Since the small unmanned airship development intended must be practical and easy to operate, the operator’s interface will have a custom design based in portable and rugged Ground Control Stations. The design and development of the ground control station is carried out under the graphical programming language LABVIEW to display the following control and status data from the airship’s autopilot, sensors and basic instrumentation telemetry:

• Latitude, longitude and altitude from the GPS system on board.

• Latitude, longitude and altitude from the Kalman filter.

• Airship’s Euler angles. • Acceleration. • Angular velocity. • Airship’s magnetic bearing. • Static Pressure. • Dynamic pressure (Pitot-Tube)

according to airship’s performance at low speeds.



The GCS also provides for the creation of the following parameters for transmission to the airship:

• Configuration parameters control system

• Static pressure in the ground station.

• Operation Mode. • Points of programmed path on

the route or planned mission It has been agreed that a condition of up to 2 hours endurance is required. Therefore, for the final system, larger capacity batteries will be required and designed in a strategic plan for Solar Cells chargers and local electrical power when available at mission’s localities.

5 THE MACHINE VISION SYSTEMS.

Our group has required assistance from the Spanish company BCB Informática y Control [4] for the development of Machine vision systems on board of our Small Unmanned airships under design. According to their engagement in our project, the company has participated in this paper with the following report: 5.1 The payload concept. The machine vision systems in conjunction with the UAS represent a convenient opportunity for low-cost applications, allowing optimum spatial, spectral and temporal resolutions. This Unmanned Aerial System can be equipped with thermal and narrowband multispectral imaging sensors, obtaining thermal imagery in the 8-14 μm region (40 cm resolution) and narrowband multispectral imagery in the 400-800 nm spectral region (20 cm resolution).

With this instrumentation, it is possible to estimate biophysical parameters using vegetation indices, namely, normalized difference vegetation index, transformed chlorophyll absorption in reflectance index/optimized soil-adjusted vegetation index, and photochemical reflectance index (PRI). In this way, the image products of leaf area index, chlorophyll content (Cab), and water stress detection from PRI index and canopy temperature can be produced. 5.2 The software and hardware design The brain of the Small Unmanned Airship is a Single-Board RIO from National Instruments combining a real-time processor, reconfigurable FPGA, and analog and digital I/O on an embedded, single board programmed with the G compiler named LabVIEW. It combines the highest performance real-time processor with a Xilinx Spartan-6 FPGA and built-in peripherals such as USB, RS232 and Ethernet to communicate with the existing sensors. With this calculation power, it is possible to integrate also the autopilot with cycle times below 10 ms, with input data from GPS, IMU (accelerometer, gyros and magnetometer) and a portable weather station. About communications, an IP modem allows to connect with ground station in real time to transmit data in a safe way. Also, Zigbee communications are used to gather information from ground sensors (while flying at low or medium altitudes). Pay load must be maintained below 8 kg. With this limitation, it is possible to place thermal and narrowband multispectral imaging sensors and a



PTZ (Pan-Tilt-Zoom) camera with an x35 optic zoom. This visible camera can be used in an automatic (with automatic tracking) or manual way (commanded by the operator using the data link). Also, FIR (Far Infrared Arrays) sensors, built on silicon are a very promising option due to their low weight and cost compared with other microbolometer-based technologies. The size of batteries defines flight endurance, but the installation of flexible panels (bigger than 6 m2) in the upper structure using OPV (Organic Photovoltaic Panels) increase endurance as much as need (of course only during sunny days). Their efficiency is poorly yet compared with silicon photovoltaic devices, but several advantages make them very interesting for this application: weight, flexibility and also low cost. 5.3 The Ground Segment The station is formed by a tablet computer for controlling the aerial platform in real-time, receiving images to analyze their quality, and changing their acquisition parameters if there is any problem. Also, a GPS receiver in the station allows knowing in a continuous way the distance between the small unmanned airship and operator. Due to the real-time data link, it is possible to receive data (and view images) from the different sensors. Also the off-line processing allows operations as image enhancement and stabilization, 3D modeling and mosaic building, view reconstruction. Sensor fusion among all the data sources is a powerful method to generate smart data, and get, for example, an estimation of biophysical parameters.

6 PHOTOGRAMMETRY For photogrammetry techniques, our research group at Mexico is partnering with the Canadian company ACCUAS Inc, one of the leaders in the field of UAS-based remote sensing and located in British Columbia, Canada [5]. The ACCUAS Inc Company uses a number of low cost UAVs for surveys of small areas. Typical horizontal accuracies achieved by the company are better than 15 cm, while vertical accuracies on most jobs are better than 20 cm. To put this in perspective the American Society for Photogrammetry and Remote Sensing (ASPRS) has drawn up a number of accuracy standards for photogrammetric surveys. The horizontal and vertical accuracies which ACCUAS achieves exceed ASPRS class 1 accuracy for 1:1,000 scale surveys, with a half meter contour interval. This level of accuracy is better than can normally be achieved from higher altitude manned photogrammetric surveys. In general UAS-based photogrammetry is similar to traditional photogrammetry undertaken from a manned aircraft. There are however a number of important differences: 6.1 Flying height A typical UAV survey is carried out at an altitude of around 300 m above ground level. This is around a tenth of the flying height for a traditional photogrammetric survey. The low flying height means that low cost compact cameras may be used, since their relatively low resolution is compensated for by the low altitude of the survey.



6.2 Camera calibration The procedure for UAS mounted cameras as those we foresee for operation in the unmanned airship under design differs from the procedure used for traditional aerial cameras. These are precision calibrated and have an associated calibration certificate, which details interior orientation parameters, such as focal length and lens distortion coefficients. The low flying height and low sensor resolution means that calibration requirements for cameras carried by small unmanned airships are generally less rigorous. Typically an off the shelf calibration package, such as Photo-Modeler, is used to establish a base calibration. Compact cameras tend to have relatively poor sensor geometry, and this may vary after several rough landings. One approach to dealing with this is to recalibrate the camera frequently on the job, using a correction grid generated from observations of reliable ground control points. This approach is well suited to small-scale UAV surveys, where dense ground control may be established with relative ease. 6.3 Image processing Small unmanned airship flights are planned in advance using dedicated flight planning software. This allows parameters such as flying height, strip orientation, and photo overlap to be specified in order to obtain the optimal coverage of the area to be surveyed. When the flight plan is complete, it is uploaded to the autopilot of the UAV. The aircraft will then fly the prepared flight plan, taking photos at the specified intervals. On landing, a dedicated log file can be downloaded from the aircraft. This contains information on the GPS position and camera attitude information for each of the photo centers.

The image processing is generally similar to the procedures used in a conventional photogrammetric survey. The log file information is used to provide initial estimates of photo positions and orientations. A rigorous block adjustment procedure, involving the use of ground control points is then used to reconstruct the correct photo geometry. Once triangulation and block adjustment are complete, detailed elevation models can be produced, which can be used to produce accurate orthophotos. 7 THE LEGAL FRAMEWORK. New UAS technology and capabilities are on the horizon for exploitation in Mexico and Latin America, but they need industry and government support for development and implementation. Both, operators and original equipment manufacturers are moving to address these issues in current and future programs aimed at the agri-business and forestry market. Unmanned Aerial System is a reality in today’s aviation world and the introduction of these vehicles in the National Air space (NAS) will depend of its complete adaptation to this new environment. In the other hand, the technologies, procedures, and regulations to enable seamless operation and integration of Small Unmanned Airships in the NAS need to be developed, validated, and employed by Latin American air authorities through rulemaking and policy development.



In Mexico, our group has obtained experience through the research and development of diverse UAS platforms, including small unmanned airships. During these activities we have found interesting issues these unmanned aerial systems must overcome to fly routinely in segregated and non-segregated airspace. Some of them are as follows:

• We have found that the array and automation of our UAS pilot stations require solve many certification issues including the mandatory resolutions about Transponder and two-way communication between the designated Pilot-In-Command (PIC), observers, flight crew and ATC, as well the associated training it requires creating a safe flight operation, so crew licensing and operator approval also will require a great deal of work and study. This means also the need for our commercial and business plan to integrate domestic and foreign manufactured UAS equipment transparently into the existing air traffic control system (ATC).

• Small unmanned airships equipment faces the need to improve “sense and avoid” technology when flying in VFR or beyond visual range. The UAS operators must conduct direct voice communications with ATC, using radio communications, which can be received by all aircraft.

• Integrating a UAS, which has no pilot in the cockpit to participate directly in the ATC voice communication network, is a

relevant challenge for Mexican Air Authority. The designated Pilot-In-Command (PIC), sitting in a UAS station in a remote location, has to rely on instrumentation to deliver flight situational awareness by Voice transmission to ATC. At the new ICAO Cir-328 [6] there is a recommendation to implement such amazingly complex automatic flight data by wired connections or ground connections to improve situational awareness to ATC Systems. This brings a new challenge to integrate software and dedicated IP ground network connections from UAS operators to ATC headquarters.

• Manned aircraft are very well understood by Mexican air authority, but UAS equipment needs to build an urgent experience roadmap to be integrated to civil operations.

8 CONCLUSIONS This paper has presented a framework for integrating small unmanned airships to agri-business and forestry industry for Latin American farmers and food producers. These UAS represent real advantages in terms of modularity, silence, substantial autonomy and high degree of controllability during normal and scheduled day and night hours. Latin America has the potential to create a strong Lighter-than-air UAS industrial (manufacturing & services) base within the agri-business strategic market & stimulate the creation of jobs.



9 ACKNOWLEDGEMENTS

• The authors express their deepest gratitude to the National Council for Science and Technology (CONACYT) of Mexico [7] and the Research and Development Center of the Ecuadorian Air force (CIDFAE) [8] for its funding and technical support to airships and unmanned vehicles research programs in previous years. Without the government policies to support science, technology and innovation, this research project could not be possible.

• We express sincere appreciation for the intense and dedicated work performed by funders, members and collaborators of the International Airship Association to promote the airship technology. Their advice and enthusiasm are invaluable for Latin American airship researchers.

• We express sincere appreciation for the valuable engagement and technical advice in photogrammetry and aerial mapping techniques from the Canadian company Accuas Inc, particularly from Scott McTavish, Darryl Jacobs and Ken Whitehead

• We express deep gratitude to Javier Bezares Del Cueto, from the Spanish company BCB Informática y Control for his valuable cooperation and assessment in vision machine systems for our UAS project.

• We express deep gratitude to James K. Yarger II, Industrial designer from the Art Institute of Portland for his valuable help in the platform design and sketches for the presentation of this paper.

10 REFERENCES

[1]The Agriculture outlook website http://www.agri-outlook.org/

[2] OCDE-FAO Agriculture Outlook 2010-2019 http://www.oecd.org/dataoecd/13/13/45438527.pdf

[3]National Forestry Commission http://www.conafor.gob.mx/biblioteca/Inventario-Nacional-Forestal-y-de-Suelos.pdf El Inventario Nacional Forestal y de Suelos de México 2004-2009. Una herramienta que da certeza a la planeación, evaluación y el desarrollo forestal de México.

[4] BCB Informática y Control. http://www.bcb.es/inicio/index.php

[5] Accuas Inc. Aerial Mapping Services, GIS & Photogrammetry. http://www.accuas.com/

[6]ICAO Circular 328 http://www.icao.int/Meetings/UAS/Documents/Circular%20328_en.pdf

[7]The National Council for Science and Technology of Mexico (CONACyT) URL: http://www.conacyt.gob.mx/

[8]Research and Development Center of the Ecuadorian Air force (CIDFAE) http://fuerzaaereaecuatoriana.mil.ec/new/?option=com_content&view=article&id=112&Itemid=222&fontstyle=f-larger