New developments in UAV navigation and control
Since we’re running essentially a navigation magazine, someone had the bright idea that maybe we could bring together the monthly review of UAS/UAV activities combined with some hint of navigation content. Seems reasonable. So delving into the academic world once more, we’ve been searching for prior papers that address novel ways for divining where a UAV might be and how it might find its way about.
Promising non-GNSS approach
Turns out investigators at the Institute of Systems Optimization (ITE) at the Karlsruhe Institute of Technology (KIT) in Germany have been working on a promising approach that does not use GNSS.
The initial premise of the ITE approach is that for future autonomous flight, especially in the potentially difficult indoor environment of search and rescue (SAR) such as in a building fire, GNSS signal reception may be little to none. But most UAVs are equipped with GNSS and inertial, so aiding the inertial solution with a back-up system is preferred. ITE chose to use a monocular camera and a 2D laser rangefinder combined into a hybrid laser-camera sensor for navigation aiding.
The camera and laser-range finder were initially calibrated by focusing from multiple different adjacent locations on one object, and so determining the attitude and translation between the two sensors. Basic navigation sans GNSS is established using the acceleration and angular rate information provided by the IMU, but inertial drift rapidly decreases accuracy, so aiding is essential.
The aiding solution has several components which are first integrated together. The camera sensor provides an initial “keyframe” from which relative motion can be derived. Continue reading about new UAV developments.