In traditional geospatial surveying, imagery for mapping and modeling purposes has to be collected with geographical coordinates. These reference points drastically improve position accuracy and product reconstruction. Even with the advent of unmanned aerial vehicle (UAV) or drone photography, ground control points (GCPs) have remained necessary despite built-in image geolocation abilities. However, recent advancements in Real Time Kinematics (RTK) may gradually replace ground control points -- providing drones the ability to deliver more precise positioning with greater ease.
Prominent areas or objects (e.g. buildings, crossings, signage) can be manually recorded through cameras or handsets with GPS capabilities. If none are readily available, such as in an empty field or jobsite, setting up a target can be just as effective. While five to ten GCPs are usually enough even for many larger projects, they have to be well distributed and can be quite far spread apart. Dangerous or difficult to navigate terrain may also impede collection. GCPs may be imported from pre-existing sources like CompassData and Google Maps, however these datasets often prove limited in scope and accuracy.
Real Time Kinematics can certainly produce similar results to well collected ground control points within centimeters of precision accuracy. By setting up two receivers (i.e. stationary reference station, operating drone), coordinates can be gathered and corrected in real-time. Everything is collected without the need to actually canvas regions of interest. RTK implementation has been limited in the past due to staggering costs and physical limitations. As drones have strict weight and power capacities, outfitting them with additional equipment has proved to be a tricky challenge. Even with recent Kickstarters and funding efforts, RTK will cost hundreds if not thousands of dollars. Swift Navigation’s Piksi kit costs roughly $995, while SenseFly’s eBee with RTK drone begins at around $45,000.
While adoption of Real Time Kinematics may prove slow and difficult, all evidence points to the inevitable. Drone operators and surveyors are always searching for fast, effective ways of delivering results -- this is simply the logical next step. As Drones have already drastically improved traditional method times and output formats, it will only be a matter of time until more efficient Real Time Kinematics will become commonplace for surveying and construction.