A Unified Formulation for the Computation of the Six-Degrees-of-Freedom-Motion-Induced Errors in Floating Doppler Wind LiDARs

Abstract

This work presents an analytical formulation to assess the six-degrees-of-freedom-motion-induced error in floating Doppler wind LiDARs (FDWLs). The error products derive from the horizontal wind speed bias and apparent turbulence intensity. Departing from a geometrical formulation of the FDWL attitude and of the LiDAR retrieval algorithm, the contributions of the rotational and translational motion to the FDWL-measured total error are computed. Central to this process is the interpretation of the velocity–azimuth display retrieval algorithm in terms of a first-order Fourier series. The obtained 6 DoF formulation is validated numerically by means of a floating LiDAR motion simulator and experimentally in nearshore and open-sea scenarios in the framework of the Pont del Petroli and IJmuiden campaigns, respectively. Both measurement campaigns involved a fixed and a floating ZephIRTM 300 LiDAR. The proposed formulation proved capable of estimating the motion-induced FDWL horizontal wind speed bias and returned similar percentiles when comparing the FDWL with the fixed LiDAR. The estimations of the turbulence intensity increment statistically matched the FDWL measurements under all motional and wind scenarios when clustering the data as a function of the buoy’s mean tilt amplitude, mean translational-velocity amplitude, and mean horizontal wind speed.

Evaluation and Wind Field Detection of Airborne Doppler Wind Lidar with Automatic Intelligent Processing in North China

“…While ground-based technologies have historically provided valuable insights into atmospheric dynamics, the detection area of the ground-based DWL is constrained by fixed locations, facing inherent limitations. To overcome these constraints and enhance DWL capabilities, researchers have explored various platform-mounted DWLs, including vehicle-mounted DWLs [17], floating DWLs [18], shipborne DWLs [19], and airborne Doppler wind lidars (ADWLs) [20]. ADWLs offer a remarkable advantage in their high mobility and flexibility, capturing detailed wind profiles across different atmospheric layers from the ground surface to higher altitudes.…”

Assessment of turbulence intensity estimates from floating lidar systems

“…However, for estimates of second-order statistics like turbulence intensity (TI), it is known that the influence of lidar motion leads to an overestimation of TI values from FLS compared to what fixed lidar systems would measure [2,3,4]. Fugro has developed a motion-compensation algorithm that effectively takes the motion out of floating lidar and hence solves the issue of motion-induced TI [3].…”