By Chris Patchell, AVIAN Australia
Drones are pretty much everywhere these days, hovering over construction sites and even weddings. In the Architecture, Engineering & Construction (AEC) industry, drones have become popular among contractors and building managers for construction inspection, land surveying, aerial asset inspection and similar applications.
They offer many benefits, from workforce safety to requiring fewer hands on a project, to expediting project schedules, covering large areas in a short time, improving measurement accuracy and other related cost savings.
But when choosing a drone provider, there are important considerations that contractors must bear in mind.
A common question that most contractors and project managers have is “do I really need a professional drone service provider?” Let’s face it, hiring a drone expert doesn’t come cheap. Some AEC companies try to avoid this expense by investing in an in-house drone.
I recommend investing in UAVs only if you have the proper training and certifications required to fly them on your site. Drone service providers could be a better choice, since they are trained to handle drone-related mishaps and ensure that the project runs smoothly with the least risk of damages.
Get to grips with the paperwork
Local drone and construction legislation
One of the first things you’ll need to do is check if the drone service provider has the necessary licenses needed to operate a drone where it will be used. Drone regulations are well established, with the Global Drone Regulations Database serving as a useful starting point to find regulations for relevant locales .
Drone legislation is rooted in drone safety protocols, and usually restricts aspects such as the weight of drones, the height at which they are allowed to fly, the airspace in which they may operate and how far in or out of sight they may be flown.
In many cases, you might need special permissions to fly drones over private properties and/or government owned spaces. It is always recommended to opt for drone surveyors who have experience in the field and work according to the current industry standards.
In addition to general drone regulations, there are also construction regulations such as measurement accuracies to bear in mind, and using a service provider with construction experience will benefit the project.
Following these rules reduce the risk of onsite damage, destruction of property, and serious accidents and injuries. Compliance to legislation also has a bearing on work cover and drone insurance.
Workcover and drone insurance
With the proliferation of professional drone work has come new insurance products. You need to consider whether your drone service provider has their own insurance, what it covers, or whether they can help you procure drone insurance for your project.
There are three types of commercial drone insurance to consider:
- Hull insurance covers the drone, camera and other equipment
- Public liability insurance covers third-party damages and on-site accidents
- Workcover insurance covers any injuries that happen to on site workers or other people because of drones.
Workcover and liability insurance are often seen as more important because they cover accidents and damages caused by drones.
You can opt for an hourly or daily based insurance policy depending on your project. If it’s a small project that can be wrapped up in day, I’d recommend you pick the hourly package.
Meet your drone service provider and understand the process
Face-to-face meetings are recommended before handing over a project to a drone service provider. However, with Covid-19 risks and travel restrictions, you might have to make do with online meetings. Drone service providers who conduct initial physical site visits can usually better gauge the project, and might be better placed to provide you with an accurate quote for the work.
Setting up a drone service agreement is essential (see example). Make sure to clearly outline the scope of the work, the expected data products, the level of processing, the accuracy of measurements, and any related issues such as data ownership, storage and reuse.
A typical drone workflow includes:
- Setting up a call and site visit
- Deciding on the drone data capture details and applications
- Conducting the drone survey / data capture
- Processing the drone data to generating 3D maps, models and other deliverables
- Sending the product(s) to client for review and incorporating client feedback
- Delivering the final data products
It is always better to be upfront with your drone service provider about your unique project requirements. This includes project insights such as:
- site measurements
- landing and take-off sites
- the angles you want to capture
- how the drone data/footage will be used
Using these insights, the drone professionals can then decide the kind of drone equipment needed for the project. For instance, if your project needs highly accurate aerial data, then an RTK or PPK drone would be an ideal fit. However, if survey accuracy is not a priority, then a standard fixed-wing drone (which is cheaper and more easily available) would suffice.
Drone data accuracy
The drone service provider will ask you a few questions before they take on your project, including:
- The site measurements
- The application of the drone data
- The required level of accuracy
- The project’s budget
Usually, contractors require drone services for land surveying, project tracking, asset management, on site repairs or maintenance.
As for drone data accuracy, there are two types of accuracies you should know about:
- Relative (local) accuracy: the accuracy of objects in the reconstructed model relative to one another.
- Absolute (global) accuracy: the accuracy of elements to their real-world position (important for property boundary surveys for example).
Weather conditions also affect drone survey accuracy since it affects altitude and flight speeds. For the best results, pick a clear sunny day with as little wind as possible for drone work.
Drone data processing and access
Once the drone data is collected, it needs to be processed and made accessible for use.
A reliable drone service provider will help you with drone data management and processing. Most drone operators use photogrammetry applications to create 3D maps and models using raw drone footage, and will be able to export it in the format you require for use in your software – but include this as a requirement in the agreement up front. Some drone service providers, such as the one your author works for (Avian), go a step further by providing clients with data-driven insights.
Drones collect and store data in a raw format. This is then exported to photogrammetry software for processing. The data is then geotagged, edited and formatted to suit your project requirements.
Data distribution, as in other sectors, has moved to online platforms, but given the size of drone datasets and the limitation of some regional network infrastructure, this might not always be a viable option, and hand-over on a hard drive might have to be done.
Establishing a long-term partnership
With the industry shifting to the full life-cycle management of a project, from its inception right throughout its operation and even decommissioning, establishing a good working relationship with a drone service provider for the project’s monitoring and maintenance could be highly beneficial.
The drone service provider’s familiarity with the project and its challenges and complications could save time over the project’s lifespan, as well as lend data consistency and smooth the workflow as the company improves its processes through the project’s lifespan.