Available Technology

Airborne Doppler Wind Profiling Algorithm

Novel method enables accurate, real-time parameter estimation in noisy environments
APOLO and its supporting data processing package were developed for NASA's Doppler Aerosol Wind (DAWN) lidar to compile three-dimensional wind profiles for improved hurricane forecasting models. The data acquisition and processing software displays wind profile parameters that include Doppler shift, power distribution, wind direction, and wind velocity. Doppler shift created by aircraft motion is measured by the internal navigation and GPS system and is fed to a signal processing system that utilizes APOLO for real-time removal of aircraft effects from wind measurements. APOLO also corrects instrument offsets that arise from GPS/INS unit misalignment, lidar telescope misalignment, and scanner installation bias. Offset compensation routines, based on the minimum mean square error principle, estimate offset angles using ground-return lidar data to compensate for their adverse effect to wind parameter estimation. APOLO utilizes two perpendicular lines of sight Doppler shift observations, compensation for aircraft motion along each line of site, then a vector sum to determine wind parameters. The technology has been utilized in a flight environment, and wind vectors have been measured from altitudes as high as 10-km. Plots of wind speed data produced by the lidar data analysis package are provided in the figures below. Similar plots of wind direction as a function of altitude are also generated from the lidar measurements.
Abstract: 
NASA's Langley Research Center have developed an algorithm, Airborne Wind Profiling Algorithm for Doppler Wind Lidar (APOLO), which offers highly accurate, realtime measurement of wind parameters (i.e., direction and speed) by airborne wind lidar sensors. APOLO enables the extraction of accurate wind speed and direction from noisy flight environments and provides correction for instrument installation biases. The algorithm has been incorporated into a supporting software package that displays accurate airborne Doppler wind lidar data and offers several data post-processing and display functionalities. The offset compensation and parameter extraction technology could be used in a variety of applications where the motion and orientation of a lidar sensor may result in data inaccuracy. NASA is seeking licensees that may benefit from integration of the compensation algorithm and data postprocessing software into existing or developing systems.
Benefits: 

Is applicable to any
dynamic lidar platform
that also employs global
positioning and inertial
navigation systems (GPS/
INS)

applications: 

Aircraft safety - clear air turbulence and
aircraft wake detection systems

Wind energy - 3-dimensional wind
mapping for offshore turbine placement
optimization and economic analysis

Wind energy - upward-looking
buoymounted lidar for offshore turbine
placement optimization and economic
analysis

Meteorology - study of weather and wind patterns

Aerial geographic surveys - aircraftmounted imaging and mapping lidar

Oceanographic surveys - shipborne mapping and navigation lidar

Reps: 
Patent Number: 
9,201,146
Internal Laboratory Ref #: 
LAR-TOPS-42
Patent Status: 
Patent Issue Date: 
April 30, 2015
Agency
NASA
State: 
Virginia
Lab Representatives
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