Data adaptive algorithms are the critically enabling technology for automatic collision avoidance system efforts at NASA’s Armstrong Flight Research Center. These Armstrong-developed algorithms provide an extensive and highly efficient encoding process for global-scale digital terrain maps (DTMs) along with a real-time decoding process to locally render map data. Available for licensing, these terrain-mapping algorithms are designed to be easily integrated into an aircraft’s existing onboard computing environment, or into an electronic flight bag (EFB) or mobile device application. In addition to its use within next-generation collision avoidance systems, the software can be adapted for use in a wide variety of applications, including aerospace satellites, automobiles, scientific research, marine charting systems, and medical devices.
NASA Armstrong collaborated with the U.S. Air Force to develop algorithms that interpret highly encoded large-area terrain maps with geographically user-defined error tolerances. A key feature of the software is its ability to locally decode and render DTMs in real time for a high-performance airplane that may need automatic course correction due to unexpected and dynamic events. Armstrong researchers are integrating the algorithms into a Global Elevation Data Adaptive Compression System (GEDACS) software package, which will enable customized maps from a variety of data sources.
The DTM software performs its high-performance encoding and decoding processes using a unique combination of regular and semi-regular geometric tiling for optimal rendering of a requested map. This tiling allows the software to retain important slope information, and continuously and accurately represent the terrain. Maps and decoding logic are integrated into an aircraft’s existing onboard computing environment, and can operate on a mobile device, an EFB, or flight-control and avionics computer systems. Users can adjust the DTM encoding routines and error tolerances to suit evolving platform and mission requirements. Maps can be tailored to the flight profiles of a wide range of aircraft, including fighter jets, UAVs, and general aviation aircraft.
The DTM and GEDACS software enable the encoding of global digital terrain data into a file size small enough to fit onto a tablet or other handheld/mobile device for next-generation ground collision avoidance. With improved digital terrain data, aircraft could attain better performance. The system monitors the ground approach and an aircraft’s ability to maneuver by predicting several multidirectional escape trajectories, a feature that will be particularly advantageous to general aviation aircraft.
Conventional DTM encoding techniques used onboard high-performance aircraft typically achieve relatively low encoding process ratios. Also, the decoding process can be computationally complex, making them unsuitable for the real-time constrained computing environments of high-performance aircraft. Implementation costs are also often prohibitive for general aviation aircraft.
This software achieves its high encoding process ratio by intelligently interpreting its maps rather than requiring absolute retention of all data. For example, the DTM software notes the perimeter and depth of a mining pit but ignores contours that are irrelevant based on the particular aircraft’s climb and turn performance, and therefore does not waste valuable computational resources. Through this type of intelligent processing, the software eliminates the need to maintain absolute retention of all data, and achieves a much higher encoding process ratio than conventional terrain-mapping software. The resulting encoding process allows users to store a larger library of DTMs in one place, enabling comprehensive map coverage at all times. Additionally, the ability to selectively tailor resolution enables high-fidelity sections of terrain data to be incorporated seamlessly into a map.
Potential applications include military and civil aeronautics (collision avoidance, aerial firefighting, crop dusting), UAV navigation and research, automotive GPS, geographical predication and planning, marine charting systems, geospatial information systems, medical software, Earth science data collection, and gaming systems.