Applanix, a mobile mapping and positioning company, has introduced a new product that enables major improvements in unmanned airborne mapping: the Applanix APX-15 UAV GNSS-Inertial System. The announcement was made at InterGeo, being held this week in Berlin
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The APX-15 UAV is designed to maximize the efficiency of mapping from small unmanned aerial vehicles (UAVs) by reducing — or even eliminating — Ground Control Points (GCPs). Sidelap is also significantly reduced, increasing the area flown per mission. The Applanix APX-15 UAV provides performance in a small package and, with the included POSPac UAV post-mission software, produces a highly accurate position and orientation solution for direct georeferencing of cameras, LIDARs and other UAS sensors, the company said.
“Applanix has recognized the need to provide the growing UAS mapping market with the same highly efficient solutions that it pioneered for airborne mapping over 15 years ago,” said Joe Hutton, Director of Inertial Technology and Airborne Products at Applanix Corporation. “We are offering a cost-effective solution that meets the size, weight, power and cost requirements of small UAS, and maintains the Applanix pedigree for quality and performance.”
The APX-15 UAV, measuring just 6 cm x 6.7 cm and weighing only 60 grams, features a high-performance, survey-grade, multi-frequency GNSS receiver and low-noise MEMS inertial sensors all on a single board. The Applanix IN-Fusion GNSS-Inertial integration technology runs directly on the GNSS receiver, resulting in an ultra-compact design, while superior performance is achieved from the inertial sensors using the Applanix SmartCal software compensation technology.
APX-15 UAV is expected to be available worldwide in the first quarter of 2015 through the Applanix sales channel.With 220 channels, the APX-15 UAV tracks all available GNSS satellite signals including GPS L1/L2/L2C/L5 and GLONASS L1/L2, QZSS, BeiDou and Galileo, and provides a highly accurate post-mission and real-time RTK GNSS-inertial position and orientation solution to support guidance and control, precision landing and sensor geo-referencing.
Comments
@Hugues - not really, no - although of course results will depend on the quality of the imaging sensor deployed. If not using a survey-grade camera that sends its own MEP, it would be necessary to characterize the delays between the trigger signal and the mid-exposure point. If such delay is small, known, and consistent, it can be taken into account in the calculations. One may want to keep a couple of GCPs as a quality control metric, but they are not required for high accuracy mapping. The APX-15 is, fundamentally, a survey-grade solution, and we anticipate that it will mostly be integrated as such into UAS used for survey mapping tasks. The value proposition is derived primarily from the time and cost saving in not having to survey a dense network of GCPs, and also in the ability to fly with much lower sidelap than for traditional AT photogrammetry, increasing the area covered in a single mission by a UAV with limited flight time.
Hope that helps.
Since there is an inevitable delay between a camera trigger pulse and the actual moment the picture is taken, since in addition, there is another delay between the camera trigger and the applanix trigger registration, the real accuracy cannot be as good as advertised. Therefore ground control points are inevitable to get real centimeter mapping accuracy.
@Hugues and @Martin - Yes. APX-15 has an event input to log camera trigger events etc with very high accuracy. Dependent on the camera deployed, this will either be a mid-exposure pulse, or can use the trigger pulse from an autopilot. This provides the data for the post-processing described in my comment to Stephen, above.
@Stephen - I'm not hugely technical, but my understanding is that there are two options: with a base station you can get real-time RTK accuracies to a few centimeters. For post-processing, APX-15 has an internal logging system that logs inertial data at 200Hz, GNSS data at at 5Hz, and events such as camera trigger time. The POSPac UAV software then uses this data, post-mission, either in conjunction with GNSS base station data, or using Applanix' SmartBase solution to generate a virtual reference station (VRS) using public-domain ephemeris information, producing a 200Hz high accuracy DGNSS position and orientation solution, Critically, the position is computed exactly at the camera perspective centre (or lidar reference point) using orientation information for the installation. POSPac UAV then uses this 200Hz solution to compute the position and orientation at every camera or lidar event that has been recorded.
Obviously, the capability of the SmartBase solution is dependent on the availability and distance of public base station data, but in most circumstances a good solution is possible without a dedicated GNSS base station.
The ability to accurately detect the moment when a photo was taken will become super critical with such system.
How does this work? Is there some kind of output to trigger a camera? How do you link positioning data with pictures? Or is this a development board for which you need to develop a software to use it?
@Doug Long - however to get the 2-5cm you need an RTK transmitter on the ground? Or can you get the same accuracy with post processing the captured GPS data?
This would be really useful where ground control points are hard to survey and locate.
@Thomas the Nerd - I think you have the idea. It's a tool for very precise direct georeferencing of aerial imagery (accurate to an inch or so) or lidar point clouds, using Applanix' proprietary technology both for calibrating the inertial sensors and coupling their output to the GNSS signals. Post-processing will provide absolute position accuracy of 2-5cm, and heading accuracy of 0.08degrees, with few or no ground control points.
For mapping-grade applications this is unbeatable, but I suspect may be beyond the performance requirements (or the financial constraints) of many hobbyists. At least this year: the technology is moving so fast that we would never say never...
And @Napoleon: that's priceless - we'll be sure to share your comment with our parent company :)
I'm new to this community - this is Applanix' first foray into the small UAV space - so please be gentle!
Based on the number of satellite signals it tracks, it's going to be expensive. This might be for sUAS, but not hobbyists.
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