Model airplanes are my father’s lifelong hobby. As soon as I was old enough to hold a transmitter, he took me flying. Although I continued to fly with him throughout high school and college, I never expected RC aircraft to become a part of my professional life!
Nearly 30 years later, I fly RC as an archaeologist collaborating on a number of excavations and archaeological research projects. Although RC technology is not new to archaeology, with the advent of multirotors, archaeologists have begun to realize the potential of small Unmanned Aerial Systems (sUAS) as low-cost aerial photography platforms.
I have been working with Yorke Rowan, of the University of Chicago, and Morag Kersel, of DePaul University in Chicago, to use RC aircraft to document ongoing archaeological projects in the Near East.
Aerial Photography and Archaeology
Archaeology is often described as a destructive science. Everything that is buried in the ground can only be excavated once. However, archaeological research includes more than simply digging. Responsible archaeologists are mindful that we should extract the maximum information from each site that we excavate. This includes intensively documenting everything we do.
Archaeologists have been using low-level aerial photographs to document their excavations for more than 100 years, beginning when Sir Henry Wellcome documented excavations in the Sudan in 1913 with a camera suspended from a kite. Overhead images of archaeological excavations are critical for recording the spatial relationships among archaeological features such as buildings, courtyards, burials, hearths, and artifacts, and they can sometimes reveal relationships between features that are not apparent from the ground.
Modern archaeologists continue to use kites, as well as balloons, poles, fruit-pickers, construction equipment, and ladders for overhead photos. Unfortunately, these methods are often unreliable, expensive, or dependent upon serendipitous access to nearby equipment. Radio-controlled aircraft provide an affordable, flexible alternative.
Equipment
In our first season using radio-controlled aerial photography in 2011, we ran a small pilot project to test the value of RC equipment for archaeology. We started by buying ARF equipment in Israel for an airplane-based platform and building a simple, small quadcopter from parts ordered online.
Encouraged by the results with these models, in 2013 we received a small grant from DePaul University as well as some financial support from the Vintage Radio Control Society (VRCS) and the Oriental Institute at the University of Chicago to build better equipment.
For this past season I selected a Skywalker 1680 foam FPV model as a platform. This airplane has been fantastic. Durable and affordable, it flies predictably, can land on a variety of surfaces with its fiberglass belly pan, and can be broken down and transported in a relatively small box.
The Skywalker can carry a moderately large 4S 5,000 mAh battery for extended flying and one or two cameras at a time—one forward facing for aerial video and one downward facing for mapping. The Skywalker also carries an ArduPilot Mega (APM) 2.5 flight-control board for tracking position via onboard GPS data. Additionally, we hope to use the APM for fully autonomous missions.
We also routinely work with multirotors. Airplanes and multirotors provide different benefits for archaeologists. Airplanes are great for mapping larger areas more quickly and they are less prone to catastrophic failures; however, airplanes require more space to launch and land, are bulkier to transport, and are slower to deploy.
Multirotors are convenient for taking aerial images of small and confined spaces and can be rapidly deployed. For these reasons, I like to have both aircraft in the field.
During this past season, we had a small 450 cm quadcopter capable of carrying a small point-and-shoot camera and a larger hexacopter capable of carrying a digital single-lens reflex (DSLR) camera. Both machines were flying “multi-Wii-” based systems.
Most of our surveys are performed using Canon S100 cameras. These cameras have decent resolution and can run Canon Hacker’s Development Kit (CHDK), an alternative firmware that gives you a variety of additional camera controls. The most important feature of CHDK is the ability to run intervalometer scripts that force the camera to take a picture every second or two for the entire time the model is aloft.
The Canon S100 also has onboard GPS for geotagging. Although this GPS is not particularly accurate while in the air, the geotags that are automatically appended to every photo can be helpful during the mapping process.
We also use GoPro Hero cameras to record onboard video. The videos from these cameras provide a visceral experience of what these sites look like from the air.
We use an infrared-enabled camera for some surveys. Infrared imagery has the potential to reveal patterns of differential growth in agricultural fields that are invisible to the naked eye. These patterns might help us identify archaeological features below the soil that are not otherwise discernible.
New Technology: 3-D Modeling
Traditionally, archaeologists have used aerial images as simple illustrations of their excavations. However, the development of 3-D photogrammetry technology now allows us to convert standard two-dimensional photographs into high-resolution 3-D data.
These models provide a visceral way to experience archaeological sites after excavations are over, so they can be a great resource for sharing our results with others, including students and the general public.
Of greater importance, 3-D models can be used, along with some additional survey data, to generate accurate maps. Unlike the original photographs, these 3-D models are undistorted and properly scaled to the real world. We generate 3-D models on several scales.
The Skywalker 1680 captures higher-altitude images that are used to generate 3-D models and topographic maps of the landscape surrounding our excavation sites. The multirotors take lower-altitude photos that are used to create 3-D models of the excavation itself.
We generally use handheld and pole aerial photography for small features such as hearths and storage pits. By building many models from all of this high- and low-altitude imagery captured over several years, we can document changes over time. This can be a great tool for tracking the progress of excavations or identifying damage caused by illegal excavation.
The 2013 Field Season
Last summer I had the opportunity to do aerial photography and mapping at several archaeological sites in Israel and Jordan. I will discuss two of them:
Wisad Pools
Wisad Pools is a massive archaeological site in the eastern desert of Badia in Jordan. The site consists of hundreds of collapsed structures, visible on the surface, spread across an area spanning several square kilometers. Use of the site covers a huge timespan—from approximately 12,000 years ago until the 4th century A.D.
Many of the structures represent tombs from later use of the site by Safaitic inhabitants in the 4th century; however, there are also many earlier domestic structures built by people in the late Neolithic Period (5500-4500 B.C.) and Chalcolithic period (4500-3600 B.C.). The site is situated around a series of natural pools that collect water in the rainy season and retain that water as standing pools well into the summer. This water resource is likely the reason people intensively utilized this area in the past.
Wisad Pools was a challenging place to fly model aircraft. It is a remote location. The nearest town is several hours away by car over poorly marked dirt tracks. During our excavation season, we camp for a few weeks at a time near the site. This means that we need to bring all of the flying gear with us and we have no access to any replacement or repair parts. We have a generator for charging batteries and I brought a large supply of small tools, glues, tapes, and spare parts to support the equipment.
More than once I found myself huddled over a diesel generator with a soldering iron, in the middle of the desert, to repair some broken electrical connectors. The site is extremely dusty and we had to work hard to protect the models from clogging up with sand during and between flights.
Wind was also a problem, and we were limited to flying at dawn when the wind was at its lowest ebb. Fortunately, this is a great time of day for aerial photography, because the early morning light evenly illuminates the ground.
Wisad Pools is located in a huge basalt boulder field. In the area we planned to map, there is hardly any portion of the ground not covered by large, rough basalt boulders. Good flat ground for landing was rare.
At Wisad Pools, we used RC aerial photographs in several ways. First, we flew the airplane over large portions of the site in order to construct topographic maps of the area that show the exact locations of visible archaeological ruins. We excavated one of the prehistoric houses this season, and topographic mapping will help us place that structure in the wider context of the rest of the site.
We flew the airplane over the pools themselves as part of a smaller project to map the location of several hundred rock art drawings carved onto nearby boulders. These carvings generally depict wild animals such as those the ancient inhabitants would have hunted. Mapping these will provide clues to how people used the landscape.
Finally, we used the hexacopter, along with pole aerial photography, to take aerial photographs of the building we excavated. These photographs will be used to build successive 3-D models showing the different phases of construction of the structure, which was originally used as a house by people in the late Neolithic Period and then was reused as a burial monument thousands of years later. These 3-D models will allow an extremely detailed reconstruction of the early and late use of the structure.
Fifa
Fifa is one of a cluster of five Early Bronze Age sites along the Dead Sea Plain in Jordan. Although it has only had limited archaeological study in the past, we know that it is a major burial center where thousands of people were interred between 3600 B.C. and 3100 B.C.
Since the early 1980s, an alarming number of these burials sites have been dug up and the burial goods sold on the illicit antiquities market, but researchers disagree on the scale and pace of the problem.
To help address the issue, Morag Kersel, of DePaul University, invited me to use UAVs as part of a long-term project documenting the damage to the site caused by illegal looting. Over the course of several days, we flew several flights with our RC airplane to get comprehensive photographic coverage of the site as it currently exists. These photographs will be turned into a detailed 3-D model of the site. This model will allow us to map individual looting pits as well as the extent of the destruction caused by looting.
More significantly, when we revisit the site each summer during the next several years, we will make new 3-D models and track how the landscape changes as new looting pits are dug. The goal is that by documenting the scale of the problem we will be able to help protect these sites in the future.
Conclusion
RC models can be a great tool for archaeologists looking for low-cost mapping solutions and 3-D modeling of archaeological sites, landscapes, and excavations. This is an exciting avenue for utilizing RC technology to support research endeavors, and it has been an exciting opportunity for me to combine two things that I love.
The next few years are likely to witness an explosion in RC use in archaeology and related fields. I am looking forward to continuing and expanding my use of these machines in the Near East and beyond.
