Advanced GNSS positioning for UAV applications

Photo of Klau GNSS device

Precise GNSS positioning is absolutely essential for today’s geomatics data gathering systems, whether air-based or ground-based, manned or unmanned, handheld or onboard vehicles. One company that is successfully integrating the latest precision-GNSS technologies into its UAV systems is Australia’s Klau Geomatics. The company’s latest positioning unit features integrated NovAtel hardware, specifically NovAtel’s OEM7700 GNSS receiver, which offers precise positioning and interference mitigation for space-constrained applications and challenging environments. NovAtel’s OEM7700 tracks all currently operational and in-development GNSS constellations, including GPS, GLONASS, Galileo, BeiDou, QZSS and NavIC.

Klau Geomatics boasts a highly creative team of geospatial and electronics experts, serving a range of clients working in precise photogrammetric aerial mapping and surveying. The company’s director, Rob Klau, said: “Our latest positioning unit is the KlauPPK 7700C. It allows users to maximise the precision of spatial localisation of aerial images for highest-quality photogrammetry. We are offering the KlauPPK 7700C in [a] variety of configurations, essentially as a customised solution to suit the specific needs of individual clients.”

NovAtel GNSS at its core

In its simplest form, the KlauPPK 7700C connects to cameras on UAVs and manned aircraft to determine highly accurate camera centre positions for each photo. Connectivity with Inertial Measurement Units (IMUs) from various manufacturers is supported to enable a simple lever arm correction in a mapping aircraft, or precise sensor attitude determination for LiDAR and other devices.

Forming the GNSS core of the 7700C is NovAtel’s OEM7700. “Rather than go with a cheap GNSS receiver and then work to try to make it perform to standards possibly beyond its capacity,” Klau said, “we start with NovAtel, a proven professional product, with established credibility and millions of hours of testing and user success, with applications in military, high-end data capture and sophisticated systems requiring robust positioning. NovAtel allows us to capture better-quality data, with advanced interference mitigation, providing more accurate and reliable results.” The data delivered by NovAtel hardware is ideally suited for his company’s PPK processing service. “The difference becomes obvious when comparing NovAtel data with data from lesser receivers,” Klau said.

Asked what he thought about NovAtel’s OEM7700, Kallan Lachrin Dickson, lead electronics tech at Klau Geomatics, had this to say: “The PCB [printed circuit board] has been designed and manufactured to the highest standard, with high quality components, and it also has great EMF [electric and magnetic field] shielding and other protection. NovAtel Connect and NovAtel Convert software [recently upgraded to NovAtel Application Suite] are both easy to understand and use, and are very handy tools when developing our product. The hardware is extremely reliable. The built-in Interference Toolkit has helped us pinpoint noise caused by other devices and has allowed us to filter out specific frequencies when required. Also, the small profile of the 60-pin connector doesn’t take up much PCB space and makes designing external hardware much easier. And, not least, the documentation is very easily accessible and includes all information needed to integrate and configure the receiver.”

Keeping it simple

“Evolving from our original, uncomplicated ‘black box’ configuration,” Klau explained, “the latest KlauPPK 7700C has an LCD screen and menu to configure connectivity with sensors such as cameras, IMUs and LiDAR, to set up camera triggering intervals, to configure data logging and so on. The system has its own chip, bare-metal programmed, remotely upgradeable and constantly expanding in capability as new use cases arise.”

For integrators who might want to work with raw components and devices to create their specific product, Klau Geomatics has put together a connectivity platform that will communicate with external devices, synchronise, then stream or log the data. “It’s all packaged up, ready to plug in and work with processing software and services to add the vital accuracy component to our customers’ systems,” Klau said.

The KlauPPK 7700C has a processor chip onboard to log full constellation data. The solution includes software developed by surveyors and geomaticians who are experts in professional, industrial photogrammetry. “Where many products, particularly in the drone world, are providing prescribed end-to-end solutions, our suite is the opposite,” Klau said. “We are offering an agnostic hardware platform to integrate the customers’ devices of choice, on a drone or not, supported with software to create the seamless solution that they are looking for.”

As another key benefit, the KlauPPK 7700C allows users to perform photogrammetry with a reduced number of ground control points (GCPs) compared to conventional methods. GCPs are markers placed on the ground, often appearing as a small section of a checkerboard, that can easily be spotted by air-based imaging systems and thus allow accurate mapping of large areas. The method is effective, but the actual placing of control points can be a challenge in many applications. It is often difficult or expensive to place new points, especially in areas inaccessible by road, or in dangerous settings, such as near cliffs or in deep, irregularly shaped quarries. Placing control points at archaeological sites, where ground surfaces may be sensitive, can also be problematic.

“There is a safety aspect here,” Klau said. “With our system, you do not have to walk around an entire site to install control points. We can achieve absolute data accuracy of around two to three centimetres in XYZ, without all the GCPs. Simultaneously, we reduce lateral overlap to 40 percent, which allows us to cover between one and a half to two times more ground in a single flight. We can connect directly to the geodetic networks of permanent stations and increase processing speed, because you only have to download your raw GNSS data, and, using the included software, the positioning will be corrected in just a few clicks.”

A solid working relationship

Klau first met Rod Macleod, APAC regional sales manager at Hexagon | NovAtel, when they worked together in the 1980s. In 2015, when Klau turned to producing high-accuracy positioning systems for drones, he wanted an established industry leader to supply his GNSS engine, so he went straight to Macleod. “Right from the start,”
Klau said, “when we began as a company, we knew we wanted to centre our products around NovAtel hardware.”

Macleod: “Rob was looking for a precision GNSS board as part of the development of a compact photogrammetric package to link to commercial digital cameras. Knowing each other since the early days of GNSS, he and I were quickly able to establish a working relationship, to develop an approach to meet his start-up requirements. This included NovAtel providing support through our application engineering team, as well as commercially supporting them as they moved to a released product.”

Since its inception, Klau Geomatics has steadily pushed the limits of product development. With the marketing of its first geospatial product, the company quickly established itself as the leader in the development of accurate navigation and positioning solutions for drones. “From our early 628 and 729 boards to our current 7700 line, including the KlauPPK 7700C,” Klau said, “NovAtel has worked to supply tailored boards to suit our needs and guided our software and hardware teams to optimise solutions.” 

The exchange has been a two-way affair, with each side helping the other to find solutions, resolve issues and improve product quality. “This collaborative relationship has helped us both,” Macleod said. “Klau gets to work with a GNSS industry leader and NovAtel gets a better understanding of the rapidly evolving, UAV-based mobile mapping market to feed back into our product development cycles. At NovAtel we do this with our customers in a number of markets, and it’s one of the reasons why they stay with us for the long term.

“Our initial discussions were based on Klau having our NovAtel OEM628 GNSS integrated correctly into their platform. Over the years, as they have expanded their business and applications, NovAtel has offered improved functionality with the OEM7 full multi-constellation tracking, more connectivity with external sensors, interference and spoofing mitigation, then real-time PPP operation with TerraStar-C PRO, removing the need for local base stations, which is a limitation in many mapping applications.”

More recently, Klau Geomatics and NovAtel have worked together on post-mission products to provide the easiest workflow for operators, who in many cases are not geospatial experts. For high-end GNSS and IMU data post-processing, including tightly coupled Kalman Filtering, Klau Geomatics uses NovAtel’s Inertial Explorer integrated with its own custom code and user interface. Inertial Explorer runs within NovAtel’s familiar Waypoint GrafNav processing environment. This powerful, highly configurable engine for data analysis comes with a standardised set of plotting tools, enabling achievement of the best possible accuracy using any and all available data. “Software is a big part of our revenue,” Klau said “with sales of our desktop software and hybrid PPK/PPP processing service.”

NovAtel has also partnered with Klau Geomatics to enable the ‘MakeItAccurate’ GNSS/IMU postprocessing service. “This is a revolutionary concept,” Klau said, “to put PPP, PPK and tightly coupled IMU Kalman filtering on the cloud, with a simple web interface or API access for enterprise. Over time, as data acquisition becomes more automated and users recognise the importance of accuracy, this service will become an essential part of large-scale corporate asset management systems. The synergy of this hardware platform and our software suite supporting post-processing, online or offline, PPK or PPP, with or without base station data, multiplies this value proposition.”

“While significant competition has now appeared in [the drone positioning] space,” Klau said, “we are still breaking new ground, integrating our positioning units with external sensors and unique processing systems. From two sales in our first year of operation to hundreds now, our sales growth trajectory has been impressive. This is due to our constant development of new cutting-edge products. Our agnostic approach and open architecture brings us more opportunities and more growth potential into the future.”

Market performance—drone-based services

NovAtel believes the drone-based services market will only continue to grow over the next five to 10 years. Additional sensors, with lower weight and higher performance, will increase the types of data acquisition and dissemination that can be performed by unmanned flying platforms. As workable regulations are implemented for beyond-visual-line-of-sight (BVLOS) operations, even more applications will become possible.

Today’s user of Klau Geomatics products is not necessarily a surveyor, Klau said. A growing market of non-geospatial users is seeking positioning accuracy, and they may not understand the fundamentals of GNSS, error propagation, photogrammetry, coordinate systems and geoids. “So part of our challenge is to bring the complexity of our products to an accessible level,” he said. 

Macleod said he sees the Klau Geomatics and NovAtel relationship continuing. “NovAtel will continue to innovate in the positioning domain and Klau will continue to
innovate on sensor integration and processing systems.” 

“This is only the beginning of the drone era,” Klau said. “The initial hype curve has passed, and serious progress continues, particularly around fully autonomous systems and integration with the growing array of sensors and devices, including airborne sensors—multispectral, thermal, LiDAR, etc.—and IoT devices. While we heavily support drones, we are also focused on manned aerial mapping, vehicle-based mobile mapping, hand-held devices and specialized applications such as offshore wave buoys and augmented reality. For as long as we are working to enable compatibility with an unlimited range of devices, NovAtel will remain at the core of our products. The data acquired with their hardware is just better; and that’s the bottom line.”

Read the full PDF here: