Integrating Systems for a Sharper LiDAR Image
Tuck Mapping Solutions enjoys a well-earned reputation as an innovator in the geospatial data collection business. The Big Stone Gap, Va., mapping firm was among the first to improve the accuracy of airborne LiDAR by installing the scanner in a helicopter for lower and slower operations. Tuck Mapping also led the industry in co-mounting an aerial camera with a LiDAR in one helicopter for simultaneous capture of imagery and elevation data.
Established as an engineering firm in 1985, Tuck Mapping has grown to a full-service photogrammetric and mapping services company that hasn’t strayed far from its roots. Now with three helicopters and two fixed-wing aircraft, the firm engineers many technical solutions to achieve the desired integration of multiple systems from different vendors. Its most recent success came with the integration of the Leica RCD30 and the Applanix POSTrack GNSS/IMU flight management system.
As company president Bobby Tuck tells it, the integration was a necessity because he already owned four POSTrack systems but knew he had to have the new medium-format RCD30 when Leica introduced it.
“The RCD30 appealed to us because it was the first digital metric camera that could replace our film cameras; it has forward motion compensation (FMC), and it collects in four bands,” says Tuck. “The size is perfect for my helicopters.”
In addition to large-area mapping projects, Tuck Mapping performs numerous corridor mapping projects each year and finds its helicopters offer better maneuverability in these applications than fixed-wing aircraft. Operated a lower altitudes, the helicopters are able to capture sharp images with the RCD30 thanks to the FMC technology.
“The metric quality of the RCD30 is outstanding,” says Tuck. “We extract phenomenal elevations from the data we capture with this camera.”
Introduced by Leica Geosystems as a digital follow-on to its RC30 film cameras – a favorite of Tuck Mapping – the RCD30 is a medium-format digital imaging system developed for a variety of photogrammetric and remote sensing applications. The 60 MP single-camera-head delivers co-registered, multispectral imagery in the red, green, blue and near IR portions of the spectrum. The sleek modular design allows the camera to fit easily in aircraft previously outfitted with film cameras.
While the Leica RCD30 is ‘plug-and-play’ compatible with Leica GNSS/IMU and flight management systems, Tuck Mapping had already standardized on the Applanix POSTrack product. POSTrack is an integration of the Applanix POS AV direct georeferencing technology, utilizing GNSS and IMU components, with the XTRACK Flight Management System software from Track’Air. Several years earlier, Tuck had integrated a Riegl LiDAR with POSTrack.
Although some operators buy sensor-control interfaces and navigation systems from different vendors, Bobby Tuck saw this as impractical for several reasons. First was the added expense of purchasing redundant components, and second was the potential confusion that could arise from flight crews having to learn and operate multiple systems, sometimes in the same aircraft. And the most significant challenge for a helicopter was the lack of interior space for installation of additional hardware.
“We wanted an integrated system that would enable our flight crews to operate the Leica RCD30 and a third-party LiDAR sensor from the single flight management interface,” says Tuck.
Tuck approached contacts at Leica Geosystems and Applanix with the idea of modifying both the RCD30 camera and the POSTrack system to function together. In addition to serving as the mission navigation system, the internal flight management software in POSTrack would have to trigger the camera at the appropriate time. And the GNSS/IMU components would have to store location and attitude data to georeference the image data during post processing.
Both companies agreed to provide technical support to the integration project.
“Bobby Tuck has such a great track record of success integrating technologies [that] it just made sense for us to support him in this,” says Joe Hutton, Applanix director of inertial technology and airborne products.
“Bobby recognized the benefits that integration would provide to all the companies involved and made the business case to Leica and Applanix,” says Jean Gardiner, general manager of Leica Geospatial Solutions in North America. “Thanks to Bobby, the RCD30 is a more affordable and attractive camera to the many aerial mapping firms now operating POSTrack systems.”
Making the Integration Work
A first-time system integration is a slow and tedious process. Tuck selected Lead’Air to perform much of the integration work because it is a subsidiary of Track’Air, which developed the XTRACK Flight Management System in the POSTrack package. The company specializes in integrating various cameras and sensors with Track’Air products.
Having spearheaded the integration of other mapping systems in the past, Tuck says the software and cabling are the two main components that must be modified. To physically link the Leica camera with the POSTrack system, Applanix designed new cables that were created by Lead’Air to transfer data and operating commands between the systems. The most important aspect of cabling is ensuring they conform to the communications protocol required by the camera. Leica provided the necessary protocol information to Tuck and Lead’Air.
The second task was rewriting the flight management system software to operate the RCD30 and trigger its data acquisitions. This involved having the FMS gather the flight altitude, location, attitude and speed information from the integrated GNSS/IMU and send that to the camera, which must know its precise coordinates to capture an image at the planned frame center point. For the camera operator, this means using the FMS interface screen to activate and monitor the RCD30 and Riegl LiDAR in the Tuck configuration.
“There just isn’t room in most aircraft for two interfaces,” says Neil DiFranco, Lead’Air product support manager.
The other software modification involved changing the file formats of the location and attitude metadata captured by the navigation system. After the flight, this data is passed along to the Leica FramePro software to post-process the RCD30 data into georeferenced images. Because of slight differences in the native header file formats used by Leica and Applanix, this proved one of the most time-consuming aspects of the project.
Once the file header glitch was worked out in the software, the integration was complete. Tuck Mapping received upgraded POSTrack software from Applanix to install in each of its four systems. Tuck now has the option of using its RCD30 in any of its helicopters and aircraft equipped with POSTrack.
Integration as a Service
Tuck Mapping now operates its RCD30 digital camera simultaneously with its Riegl LiDAR, both controlled through a single interface linked to the flight management system in POSTrack, which also collects location and attitude metadata for post-processing. One onboard computer runs the hardware and software from an interface that is familiar to the Tuck Mapping personnel.
The combined system works so well that Lead’Air now offers the RCD30/POSTrack integration as a commercially available service. “Lead’Air is leading the curve right now on integrating sensors with POSTrack,” says Hutton. “Their forte is integrating systems into airframes and making sure everyone’s equipment works together.”
Bobby Tuck and Lead’Air’s DiFranco offer identical advice for anyone considering integrating an airborne sensor with a navigation or flight management system from a different vendor. The key is to let the integration company know exactly which sensors will be used in the aircraft – just as Tuck let Lead’Air know a Riegl LiDAR would be used with the Leica camera. And it’s important to describe the type of mapping projects that will be performed.
“Even for an integration we’ve done in the past, there’s a custom element to each one,” says DiFranco. “We need to get the big picture overview of how all the equipment will be operating.”
Ruedi Wagner, general manager of Leica Geospatial Solutions worldwide, predicts that the mapping industry will experience greater compatibility of vendor components in the future. “Leica sees itself as a solutions provider for our clients, and that means ensuring our products are compatible with those of other manufacturers,” he says.
Designing products with an open interface benefits the industry as a whole, and it also creates new opportunities for everyone involved. “There are a lot of aerial mapping firms that are going to take a second look at buying the RCD30 now that it integrates with the POSTrack,” says Tuck.
For more information about Tuck Mapping Solutions, visit www.tuckmapping.com. Additional information about the RCD30 camera can be found at http://www.leica-geosystems.us/en/Leica-RCD30_86987.htm. Lead’Air can be reached through www.trackair.com, and Applanix is at www.applanix.com.