Drone mapping technology has advanced significantly in recent years, with Real-Time Kinematic (RTK) and Post-Processed Kinematic (PPK) positioning emerging as game-changing technologies. These methods enhance mapping accuracy and efficiency, reducing reliance on traditional Ground Control Points (GCPs). SimActive, a leading provider of photogrammetry software, offers powerful tools for geospatial professionals, including its flagship product, Correlator3D. This high-performance platform is designed for processing imagery from drones, manned aircraft, and satellites, enabling users to generate precise maps with speed and ease.
Eric Andelin, Senior Workflow Specialist at SimActive, shares key insights into how RTK and PPK are shaping the field of drone mapping, their advantages and challenges, and what professionals should consider when implementing these technologies.
Understanding RTK and PPK in Drone Mapping
Both RTK and PPK enhance positional accuracy in drone mapping by correcting GPS data errors, but they differ in their implementation. “RTK requires a base station and a rover—where the drone acts as the rover,” Andelin explains. “The base station must be set up over a known surveyed point within the project area.” In contrast, PPK eliminates the need for an on-site base station by leveraging external networks, such as NOAA’s Continuously Operating Reference Station (CORS) or private correction services.
Accuracy and Reliability: RTK/PPK vs. Traditional GCPs
RTK and PPK offer high accuracy, but Andelin emphasizes the importance of validation. “Since RTK involves a known on-site base, setting a network of targets helps validate its reliability. If the RTK signal fails during flight, targeted control can salvage the mapping data,” he explains. PPK provides more flexibility, as it does not require a continuous connection; however, using targeted control ensures the highest level of accuracy.
Cost and Efficiency Benefits
Compared to traditional GCP-based methods, RTK and PPK can offer significant cost and time savings. “RTK requires some traditional survey equipment and a cell phone connection, whereas PPK eliminates the need for additional survey equipment,” says Andelin. While PPK-equipped drones have higher initial costs, the advantages often outweigh the investment. “Given the benefits, the added cost of robust PPK positioning is negligible for many operators.”
Technical Challenges and Limitations
Despite their benefits, both RTK and PPK come with challenges. “RTK requires a constant connection with the drone during flight. If that connection is lost, a reflight may be necessary,” Andelin notes. PPK, on the other hand, is more forgiving in data collection but requires waiting for ephemeris data, which can take several days to a week to be published.
Environmental factors also play a role in the effectiveness of these technologies. Areas with dense vegetation, urban canyons, or interference-prone environments may impact RTK connectivity, making PPK a more suitable choice in such scenarios.
Adoption and Industry Impact
The adoption of RTK and PPK has significantly influenced drone mapping practices. “All drones inherently have some form of positioning stamped onto their imagery. With targeted control, excellent results can be achieved,” Andelin says. However, he cautions against over-reliance on RTK and PPK alone. “These technologies provide much better positioning accuracy, but they can lead to false confidence. Some users start reducing or even eliminating control points, which is a mistake. The only way to verify accuracy is through targeted control.”
The Future of GCPs in Mapping
While RTK and PPK reduce the need for extensive GCP networks, Andelin does not foresee GCPs becoming obsolete. “Targeted control is the only way to validate photogrammetry results. Without it, you’re just close—but you can’t quantify how close,” he states. This validation remains crucial for high-precision mapping applications.
Advice for Drone Pilots Transitioning to RTK/PPK
For drone pilots looking to integrate RTK/PPK, Andelin offers practical guidance: “Set a network of targets using ASPRS guidelines and have them professionally surveyed. Fly your project with the drone you’re most comfortable with, using whatever positioning is available. Process your results and check them against the targeted control. If anything is wrong with the RTK or PPK-derived positioning, photogrammetry can salvage the data.”
Regulatory Considerations
Drone mapping professionals must also consider regulatory requirements. “Each state has its own regulations when it comes to surveying,” Andelin points out. “Photogrammetry differs from traditional surveying and requires a distinct skill set, but it still relies on survey data for accuracy. Before mapping for profit, operators should familiarize themselves with their state’s regulations.”
As drone technology continues to evolve, RTK and PPK provide powerful tools for enhancing mapping accuracy and efficiency. However, targeted control remains essential for validation, ensuring reliable and verifiable results. SimActive’s Correlator3D enables geospatial professionals to leverage these technologies effectively, offering a robust solution for drone-based photogrammetry. As industry adoption grows, understanding the nuances of RTK and PPK will be key to producing high-quality, reliable maps.
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Miriam McNabb is the Editor-in-Chief of DRONELIFE and CEO of JobForDrones, a professional drone services marketplace, and a fascinated observer of the emerging drone industry and the regulatory environment for drones. Miriam has penned over 3,000 articles focused on the commercial drone space and is an international speaker and recognized figure in the industry. Miriam has a degree from the University of Chicago and over 20 years of experience in high tech sales and marketing for new technologies.
For drone industry consulting or writing, Email Miriam.
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