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Autonomous Aerial Surveying

CDM Smith is helping a confidential energy client comply with regulatory requirements throughout the design and construction of a large solar farm, leveraging UAV technology to monitor environmental impact and implement a one-of-a-kind solution.

Australia’s solar energy market is shining brightly, riding an industry boom that began a few years ago and is forecast to continue. This method of generating electricity becomes increas­ingly appealing as energy prices continue to rise and solar panel costs become more efficient and affordable. Fueled by the country’s abundant solar irradiance, consumers and companies have begun gravitating toward solar energy, installing panels on the rooftops of homes and building solar farms to reap the benefits of clean energy on a larger scale. CDM Smith is helping one of those companies, a confi­den­tial client, comply with regulatory require­ments throughout the design and construc­tion of a large solar farm by using autonomous unmanned aerial vehicles (UAVs), known commonly as drones, to monitor envi­ron­men­tal impacts.
 
Innovation in Flight
Monitoring envi­ron­men­tal impacts throughout the project lifecycle is key to meeting regulatory require­ments and potentially reducing significant financial obligations. The solar farm permit conditions allowed for reduced monetary install­ments to the government where mini­miza­tion of impacts to vegetation could be demon­strated. To help the client obtain that benefit, CDM Smith’s team considered the best way to establish existing on ground conditions and track vegetation loss. Infra­struc­ture specialist Taylor Oldfield and engineer Evan O’Brien took this challenge as an opportunity to innovate and within the surveying process. “Previously, this type of information was collected by personnel on foot and proved to be a costly, time consuming, tedious process,” said Taylor. Recognising that fact, Taylor and Evan turned to UAVs to improve the surveying process. “Using this technology, we were able to deliver high-accuracy, high-resolution deliv­er­ables to the client in a more timely and cost-effective manner than a traditional ground-based survey could provide,” said Taylor.
 
Using UAVs, the team could provide the client with robust data in a timely and cost-effective manner. “We recognized a major discrepancy between the quantity and quality of data you can obtain by sending two workers into the field to survey compared to sending up an aircraft with Airborne Laser Scanning (ALS) capa­bil­i­ties, with little to no options in between. UAVs provide something between these two levels of data capture, which is appealing to those who may be working on a tight budget or don’t have access to an aircraft with ALS,” explained Evan. According to Evan, the UAVs also bolster safety, removing risks for workers in the field through a hands-off data capture method: “For those working in potentially dangerous locations, surveying using drones is a game-changer. Some tasks are not only time consuming, but dangerous. Using a machine removes the element of danger to employees.”
 
The UAVs Evan and Taylor deployed collected detailed photographs that can be stitched together with photogram­met­ric techniques—or techniques that help make measure­ments using photographs—to provide a cost and time efficient method for tracking vegetation loss throughout construc­tion. More than 4,000 photographs were captured and collected for processing to provide rich datasets to the client. Combined with highly accurate GPS data, the team created robust 3D models, including a detailed digital terrain model, that would not only be essential for monitoring vegetation loss over time but supplement both the design and construc­tion phases of the project.

The barriers to owning and operating a drone have dropped significantly since they entered the market - and this project is evidence that you don't need expensive technology to capture rich data.
Taylor oldfield, cdm smith infrastructure specialist

Scaling Up Operations, Staying Grounded in the Data
Taylor and Evan used their knowledge and personal passion for UAV technologies to plan the data capture process, creating a detailed project plan to guide smooth execution. “The barriers to owning and operating a drone have dropped significantly since they entered the market—and this project is evidence that you don’t need expensive technology and equipment to capture rich data,” said Taylor. The drone they used flew autonomously in a grid-based pattern at specific altitudes and frequencies, capturing imagery at intervals. With flight parameters for the drone identified and equipment at the ready, the team deployed small-scale trials to pilot and test their process before upscaling and deploying in the field. “When you do aerial surveying,” explained Evan, “you need to tie your observations to ground control points—or recognizable locations on the ground—so you can accurately tie your photographs together during data processing. Any number of upscale products, like reflective targets or markers, do the job, but what we actually used were a bunch of brightly colored foam squares we picked up at a local store.”

Going Global to Gain Insights
Capturing the data was only the beginning of the process. To improve their data processing capa­bil­i­ties, Evan and Taylor collab­o­rated with CDM Smith’s global resources. “By reaching out to experts in North America,” said Taylor, “we were able to gain insights on the right platforms, processing methods and software to efficiently process the data at hand. We had to consider the timeliness of the data and think carefully about how often we should deploy the drone as to not overwhelm ourselves with data.” This allowed CDM Smith to be a one-stop-shop for all data capture and processing needs, opening a realm of possi­bil­i­ties by reducing the manpower required to deliver results and increasing the amount of control the team has on the data.
 
The team will repeat the process at set project milestones to account for changes to vegetation over time and compare vegetation on the site once construc­tion is completed early in 2019. While the deliv­er­ables are greatly assisting project design and regulatory compliance during construc­tion, there is a significant direct financial benefit to the client through reduced government payments. Based on the success of this initial program, the client is now seeking similar UAV surveys at the beginning of project planning for two new greenfield solar farms in central Australia.
 
Through teamwork and shared initiative, Taylor and Evan sought out the resources necessary to improve the collection, processing and delivery of data, proving that expensive equipment is not always needed to deliver a sophisticated solution. “I really enjoyed the practical engineering aspect of this project,” said Evan. “It’s easy to get caught up in the high-tech angle of what we do, but there is still a place for simplicity without sacrificing quality. You don’t have to buy the most expensive platform to deliver an excellent outcome for the client.”

For those working in potentially dangerous locations, surveying using drones is a game-changer. Some tasks are not only time consuming, but dangerous. Using a machine removes the element of danger to employees.
Would you like to know how Autonomous Aerial Surveying can assist with your next project?
Contact Evan O'Brien - Associate Engineer at CDM Smith for more information.

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