Guest Column: Essential Steps to Start Surveying with Drones
With the implementation of new laws governing commercial UAVs (unmanned aerial vehicles, informally called drones), the FAA has removed the most significant hurdle to using drones at work. In our experience helping surveyors integrate UAVs into their operations, we have learned that setting up an effective UAV operation requires knowledge and effort. However, the state of regulation and technology means that it is feasible for nearly all surveyors to bring UAV operations in-house today.
While many industries are using drones, few are benefiting as much as land surveyors. For a land surveyor, a drone is a powerful tool for efficiently, easily and safely creating aerial orthophotos and topographic data faster than ever. While UAVs are capable and efficient, using them effectively requires more than simply expecting automatic results. Creating real business value with a drone requires following a series of essential steps.
First, a surveyor must understand and select the right technology for their needs -- hardware and software.
Next, in order to reliably produce good results, a surveyor has to put in place clear, well-defined operations, including training, procedures and safety considerations.
Finally, a surveyor needs to make sure that the UAV operations are fully insured, supported and comply with FAA regulations.
Identify the right technology
Producing results with a drone requires multiple hardware and software components. The hardware needed is a drone airframe, camera and ground station; the software needed are mission planning, autopilot and data processing.
UAV capabilities vary widely in each of these three components.
Airframes broadly consist of either fixed-wing or multirotor types. Fixed-wing UAVs can generally fly further and longer, however this benefit is moot because regulations currently require the operator to maintain line of sight with the UAV. Even a fairly basic multirotor UAV can easily cover as much area in one flight as can be maintained within line of sight. Multirotors are made in a variety of rotor arrangements. More rotors generally means more carrying-capacity, but most survey operations can be completed with a standard quadrotor.
While UAV manufacturers are starting to explore mounting LiDAR systems on UAVs, users will benefit most from a UAV with a standard digital camera. The higher the image quality produced by the camera (in terms of megapixels, lens quality and sensor type), the more accurate the map produced. Many good UAV options have integrated cameras that provide good quality imagery. Many higher-end UAVs are capable of carrying bigger cameras, but the real-world benefits of anything beyond a good quality point-and-shoot for this type of photography is minimal.
The ground station controls the UAV while in operation. For some higher-end UAVs, this may consist of an elaborate setup including a laptop, controller and set of transmitter antennas. However, the capable UAVs we often recommend incorporate all of these components into a smart controller that is paired with a tablet.
UAV hardware costs vary even more, with some systems costing well over $100,000. In our experience, most land surveyors can expect significant returns on an investment of less than $15,000 total. We recommend simpler and less-expensive hardware; this will provide the core capabilities needed to generate value without the risk of overpaying for the unnecessary. Only a small minority of surveyors will benefit from cutting-edge, high-end UAV technology enough to make the added expense and complication worthwhile.
Before heading out to a field site with a UAV, a surveyor should use mission planning software to prepare. Mission planning covers everything that happens before the autopilot is programmed: evaluating whether the full job site needs to be sub-divided into multiple flights, checking weather (minimal precipitation, good visibility and less than 15 mph winds, for example), and making sure that the operation avoids any restricted airspace. Mission planning feeds directly into the operational planning, as well as the autopilot software.
Innovation in autopilot software has been key in enabling the widespread adoption of UAVs. Many UAVs come with pre-packaged autopilot software, and high-quality third-party autopilots are inexpensive and readily available for others. Most autopilots work by allowing the operator to simply trace out the parcel of land to be surveyed on an interface similar to Google Maps. The user then needs only to specify the altitude to be flown and the photo overlap desired. The software does the rest. With the right autopilot software, operating the UAV requires little more than the press of a button; the software automatically pilots the aircraft and captures the photos.
While autopilot software has made operating a UAV very straightforward, it is important to understand its limitations. At this point, autopilot does not include collision avoidance; it is up to the operator to ensure that the planned flight avoids obstacles like trees, buildings, hills or power lines.
Simply collecting a set of aerial photos over a parcel of land is not the end, the photos must be turned into a deliverable that provides value to a land surveyor. The multiple data processing solutions that exist all operate on the same underlying principles of photogrammetry. The photos the drone collects are stitched together and georeferenced using the GPS from the UAV. Stitching together the photos produces two primary outputs: a single orthorectified photograph and a three-dimensional model of the terrain.
Many land surveyors use the georeferenced orthophoto as a deliverable in its own right, or use it as the backdrop to planimetric linework. The photogrammetric processing software also produces 3D data as a point cloud and a triangle mesh surface model. For firms familiar with handling 3D data, the point cloud or triangle mesh can be highly valuable as it allows surveyors to pull contour and breakline data directly from the model, or even for engineers to design directly from the model. For firms that do not regularly handle 3D data, we recommend starting a UAV program around producing 2D deliverables and expanding to 3D once the initial investment has proven its value.
Implement smart operations
Understanding and implementing the right operations is key to reliably producing good results with a UAV. Training, planning for needed deliverables and planning for exigencies are all essential to effective operations.
In order to ensure reliable and safe drone operations, training is crucial. UAVs are an exciting new technology, but in order to be an effective part of a survey business, personnel have to understand how to operate them reliably. Ultimately, a drone must be considered another technical tool for a surveyor, alongside robotic total stations and GPS. Specific, focused training is a necessity if a drone investment is going to realize its potential.
As land surveyors know well, business success often hinges on having disciplined and well-defined operations. As the profitability of a survey project relies on minimizing site revisits, the effectiveness of a drone survey hinges on reliably collecting the right data the first time. Before embarking on any UAV survey, it is important to first be clear on the required deliverable.
The single most important operational consideration is safety. Commercial UAVs have become highly reliable, but the skies must be treated with excessive caution. Good operations are developed based on a thorough understanding of what emergencies could occur and having rigorous procedures for responding.
With UAVs, two dimensions of safety must be considered: ground and sky. While the UAVs we recommend are highly reliable, a safe operator will consider the consequences of the UAV failing mid-flight.
Understand the rules
Commercial drone regulations have been unclear and complicated over the past several years, but the FAA has finally put in place clear rules that are favorable to many survey operations. The law is fairly in-depth, but the most important rules for surveyors to be aware of are licensing, flying altitude and maintaining line of sight. (A detailed discussion of the new regulations is contained in What the New FAA Drone Rule Means for Surveyors, also in this issue).
Simply put, commercial drone operators are required to pass a knowledge test and be vetted by the TSA to receive permission from the FAA to fly a drone.
Prepare for contingencies
UAV technology has become highly reliable remarkably quickly. However, it is still essential to prepare for the unexpected. UAV insurance is readily accessible for most businesses, covering both liability (since most commercial general liability policies exclude anything that flies) and the equipment itself.
Insurance covers the worst-case scenario, but it is equally important to plan for the possibility of other challenges. Having access to reliable, trustworthy support that can be tapped to resolve technological or operational breakdowns is essential in ensuring that a drone investment delivers its returns.
The UAV era has finally arrived
Years of hype and media attention have made many businesses wary of investing in UAVs, but new laws and matured technology mean that the time has come for smart surveyors to act.
Integrating such new technology is not easy, but by ensuring that each factor of the UAV program has been addressed, success is achievable. UAVs are already proving profitable for surveyors around the United States.