UAVs, sUAS, RPAS, multicopters, drones. Their name is almost as varied as their uses. Once only conjuring up images of military surveillance and perhaps, with the success of a well-spun marketing ploy, pizza delivery, their wider variety of applications has entered the public consciousness to a greater degree as their presence approaches the level of the ubiquitous.
With advances in technology and high levels of competition between the top manufacturers (think DJI and 3DR) they have become more and more affordable which, while increasing hobbyist use, has also served to increase and make more accessible their commercial and industrial applications.
Photographers and videographers have included them in their arsenal. Aerial shots of real estate are almost omnipresent. Aerial pans in broadcast media: more and more commonly the work of a drone rather than of a helicopter.
Bridge and roof inspections
Drones are filling the skies for inspection purposes. Bridge and roof inspections. Masts, turbines: anything where dangerous manned access has previously prevailed. Insurance and loss-adjusting comes to mind. A drone on every worksite. Almost everyone on a large construction site has encountered them at some stage and the same goes for civil engineering projects.
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The construction site at Cherrywood[/caption]
Contractors for big projects across the board have readily adopted the use of drone aerial imagery and footage, commonly to contribute to progress reports on a monthly basis.
Project managers can identify problem areas in a report to be shared with the client and stakeholders. Clients seek to make use of imagery and footage to be put together throughout the life of the project for story-boarding purposes.
Disruption in construction, engineering and mining
The latest in cutting edge is leading to disruption in construction, engineering and mining. A number of directly competing specialised drone Software as a Service solutions are constantly being developed and refined. DroneDeploy, Pix4D and Skycatch, to name a few of these, allow for 3D model creation and 2D orthomosaics from imagery captured from a range of drones starting at around the prosumer grade up to the professional.
For the typical drone, the user connects their device and launches the app from which they can control settings and view a live HD feed from the camera to their device screen. The drone software packages above replaces the app with their own and allows users to create autonomous flight paths rather than allowing users to fly manually.
The user can draw an area of which they wish to map.
The drone takes off autonomously and flies along the plotted route. Below is an example of a route that the drone will fly along.
While the drone flies this route it is capturing nadir imagery at intervals of two to three seconds with the camera pointing directly down at 0°. The images captured are geotagged. Depending on the size of the area being mapped, this may be taken over the course of a number of flights to allow for battery changes, the drone restarting the route from where it stopped between each change.
Nadir imagery generally sufficient for terrain models
Depending also on the acreage, hundreds of images will be captured. In the case of structures, further imagery can be captured manually using the original drone app to capture obliques of the sides of the structure at different heights and angles to create a better-looking model. This can be done for buildings and properties. Nadir imagery is generally sufficient for terrain models.
When all the images have been captured they can be uploaded to the software. They are processed and stitched and returned to the user as a 3D model that can be navigated and explored. This can allow for exploration and inspection of large sites.
The file can be integrated with AutoCAD and BiM, allowing everyone on site to collaborate on progress with the integrated overlays. Communication on scheduling with the client and stakeholders is advanced to a higher level. High resolution 2D orthmosaics map out the entire site from above and can serve as a further photographic evidence tool to mitigate risk.
3D volumetric tools
Instant 2D measurements (distance and area) can be achieved and 3D volumetric tools can replace traditional surveying techniques removing the time and danger elements associated with walking around a site getting measurements. Use of the software in conjunction with RTK equipment to get Ground Control Points (GCPs) is desirable in order to achieve higher global accuracy.
This may only be required once, and from then clients will be able to get volumetrics on-demand and at a far more cost-effective level too. Take the mining industry. Volume calculations will be needed throughout the year for auditory and inventory purposes. Once the ground-control points have been established this suffices for future mapping.
Repeated mapping highly cost-effective
Another mapping of the site with the software for another calculation of all stockpiles is all that is required. Construction sites may already have these in place. Repeated mapping would be highly cost effective and the savings can be passed onto the client.
Construction can make use of such repeated surveying for purchase planning and quantifying of amounts removed and actual work done.
While drones have found themselves well into various industries as discussed, certain of their applications are on the verge of making themselves better known. Aggregate companies have for decades measured stockpiles using a combination of employees and third party surveyors.
Costs associated with surveying equipment, lengthy processes including walking on site and climbing up and down huge stockpiles and the health and safety and associated insurance costs with this process have meant that bills for surveying quickly mount. Drone surveying offers a safer, quicker and more cost-effective alternative.
New take on photogrammetry
The method isn’t new but rather a new take on photogrammetry, a method which has been around almost as long as manned aircraft. Aerial surveys however have acted as somewhat of a luxury for the mining industry in the past. As the drone makes its way in however, this no longer need be the case.
Certain applications are further streamlining the process such as senseFly’s eBee which carries built-in RTK, meaning Ground Control Points don’t need to be measured. While these drones come at a higher price tag, high competition continues to drive technology forward in the industry while making it all the more affordable.
The bridge is currently being gapped between time-intensive ground based surveying and expensive aerial surveying and it won’t be long before the evidence of that is as apparent as in some of the other sectors mentioned. It’s a drone on every large construction site and big project. Soon it will be a drone in every mine.
Author: Niall Gates is a serial entrepreneur. For drone surveying and 3D modelling queries: https://www.datadrone.ie. His primary domain is at http://gatesmedia.ie/ which serves as the starting point for marketing his own and others' companies. For drone surveying and 3D modelling queries he can be reached by email at niall@datadrone.ie and by phone at 0860855409