Affordable RPAS gives surveyors a new edge


Reyburn & Bryant is a Northland survey firm that specialises in cadastral and subdivision work from Kaitaia in the north and as far south as Mangawhai to the south.

Having kept a close eye on industry developments in aerial mapping technology, the company had been reluctant to invest in a Remotely Piloted Aircraft System (RPAS) as the cost was prohibitive for the amount of work it would generate.

“Much of the Northland is covered by dense bush and scrub, whilst grassy areas are often left to grow naturally giving you little idea of the terrain underneath,” said Chris Knapp, a senior surveyor for the firm. “For that reason our use of RPAS technology is somewhat limited as for many areas you would need traditional survey methods anyway.”

Mr Knapp explained the company had received a demo of an RPAS solution, however, the costs outweighed the benefits. “The system we were shown was quite cumbersome and we would also need to invest in supercomputers to be able to process and store the data, so we decided to wait until something more manageable was available,” he said.

Reyburn & Bryant’s decision making process was accelerated by a large quarry customer who had changed their health and safety policy in favour of completing stockpile volume surveys using only aerial mapping technology.

“They asked if we were able to comply with their new regulations, so their request put a bit of pressure on to find a solution that would work for us,” Mr Knapp said.

When Aptella presented a bundle solution that incorporated a DJI Matrice 100 aircraft, along with Propeller AeroPoints and Propeller data analysis software, Mr Knapp was impressed.

DJI is a global powerhouse when it comes to high performance, cost effective drones, with its popular Phantom 4 now available in many consumer electronics shops. The Matrice 100, or M100, is an industry-grade platform that incorporates advanced in-flight stability, collision avoidance and long battery life for larger applications.

Propeller AeroPoints are lightweight, square ground control points that combine GNSS positioning with clear markings that make them highly visible in orthophotogrammetry. Their simple one-button operation allows for instant connection and processing to the Propeller web-based processing platform to deliver survey-grade accuracy.

As a simpler, more cost effective and yet extremely accurate solution, Mr Knapp said they have been pleased with the system’s performance. “We went into it somewhat blind having never used survey drone technology before, however the AeroPoint ground control system is very effective and it processes up well – we keep the points in a tight network to give us great accuracy.”

To verify the accuracy achieved on some of the earlier projects, Reyburn & Bryant checked and compared their results with RTK GPS. “We were easily within 0.1 of a metre accuracy, which was well within tolerance levels and for some flood mapping work our tolerance was half a metre and we achieved well within 0.2 of a metre.”

Not having to rely on desktop-based post-processing software is also a great advantage, Mr Knapp explained. “Propeller allows us to analyse and share the data with clients, without having to transfer huge datasets. It’s also enabled us to add extra value to clients by providing a DWG file to engineers for them to use in modelling applications, or simply to provide high-resolution orthophotos of the site, which are also very popular,” he said.

With the added services Reyburn & Bryant is able to offer clients, Mr Knapp said it has proved a valuable and cost-effective solution.

“Initially we needed some support from the local supplier Aptella while we were learning the ropes, but after we’d ironed out some teething bumps everything’s been plain sailing,” he said.

“Having expertise at hand from a supplier is extremely important with any new technology and we value the relationship we have with Aptella,” he added.

In the future, Mr Knapp sees RPAS being used more and more both through demand from a health and safety perspective from clients and also as a time saving and productivity enhancer. “Once the survey drones are able to carry LIDAR and can model any terrain, I think we’ll see them replace the use of traditional survey methods for a number of applications,” he said.

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