This Special Issue “Atmospheric Conditions for Wind Energy Applications” hosts papers on aspects of remote sensing for atmospheric conditions for wind energy applications. Wind lidar technology is ...presented from a theoretical view on the coherent focused Doppler lidar principles. Furthermore, wind lidar for applied use for wind turbine control, wind farm wake, and gust characterizations is presented, as well as methods to reduce uncertainty when using lidar in complex terrain. Wind lidar observations are used to validate numerical model results. Wind Doppler lidar mounted on aircraft used for observing winds in hurricane conditions and Doppler radar on the ground used for very short-term wind forecasting are presented. For the offshore environment, floating lidar data processing is presented as well as an experiment with wind-profiling lidar on a ferry for model validation. Assessments of wind resources in the coastal zone using wind-profiling lidar and global wind maps using satellite data are presented.
Mittlerweile werden in Smartphones immer mehr Sensoren verbaut, welche die Nutzerfreundlichkeit erhöhen sollen. So finden sich in einigen Modellen Lidar‐Sensoren, die unter anderem zur ...Abstandsmessung genutzt werden können. Dieser Sensor ermöglicht weitere physikalische Untersuchungen, wie die Messung der Lichtgeschwindigkeit in Flüssigkeiten oder anderen transparenten Medien.
Localization and Mapping Systems
In article number 2200459, Dongjiao He, Wei Xu, and colleagues present a high‐bandwidth LiDAR‐inertial system (LIO), which updates the state at the sampling time of ...each LiDAR point or IMU measurement without accumulating a frame. The system is motion distortion free and is able to output a high‐rate (4 kHz – 8 kHz), high‐bandwidth (over 150 Hz) odometry and handles extremely aggressive motions where IMU saturates.
Capturing and quantifying the world in three dimensions (x,y,z) using light detection and ranging (lidar) technology drives fundamental advances in the Earth and Ecological Sciences (EES). However, ...additional lidar dimensions offer the possibility to transcend basic 3-D mapping capabilities, including i) the physical time (t) dimension from repeat lidar acquisition and ii) laser return intensity (LRIλ) data dimension based on the brightness of single- or multi-wavelength (λ) laser returns. The additional dimensions thus add to the x,y, and z dimensions to constitute the five dimensions of lidar (x,y,z, t, LRIλ1… λn). This broader spectrum of lidar dimensionality has already revealed new insights across multiple EES topics, and will enable a wide range of new research and applications. Here, we review recent advances based on repeat lidar collections and analysis of LRI data to highlight novel applications of lidar remote sensing beyond 3-D. Our review outlines the potential and current challenges of time and LRI information from lidar sensors to expand the scope of research applications and insights across the full range of EES applications.
•X, y, z, time, and laser return intensity constitute the 5-dimensions of LiDAR.•We review recent advances to highlight novel applications of LiDAR beyond 3D.•Beyond 3D LiDAR has and will enable a wide range of new research and applications.
Pri izvedbi so sodelovali različni deležniki: - konzorcij geodetskih podjetij (zunanji izvajalec), izbran na javnem razpisu (LGB d.o.o., Digi data d.o.o., Geodetski zavod Celje d.o.o., Ljubljanski ...urbanistični zavod d.d., Monolit d.o.o), je skrbel za določitev referenčnih - veznih točk na podlagi terenske izmere in interpretacije podatkov državnega ortofota (DOF) ter podatkov LIDAR in za zajem dodatnih geometrijskih pogojev iz arhivskih elaboratov zemljiškega katastra; - Geodetski inštitut Slovenije je sodeloval v projektu kot vmesni člen med zunanjim izvajalcem in Geodetsko upravo Republike Slovenije (v nadaljevanju: geodetska uprava) ter skrbel za nemoteno izmenjavo podatkov, kontrolo in arhiviranje rezultatov zunanjega izvajalca ter razne prikaze in statistično obdelavo; - ekipa referentov izboljšave (skupaj 30 referentov), sestavljena iz sodelavcev vseh območnih geodetskih uprav in Urada za nepremičnine, ki je s posebej razvitimi oziroma kupljenimi programskimi rešitvami izvajala proces lokacijske izboljšave z metodo homogenizacije podatkov; - ekipa referentov geodetskih pisarn, ki so se vključevali v projekt, ko se je izvajal na območju njihovih pisarn, tako da so skrbeli za pripravo vhodnih podatkov iz obstoječih lokalnih baz zemljiškega katastra in evidentiranje rezultatov. Ob občasni pomoči ostalih sodelavcev v geodetski pisarni pa so skrbeli še za odpravo napak in neskladij med podatki, ki so bila ugotovljena v procesu lokacijske izboljšave. V informacijskem sistemu zemljiškega katastra je ostal ZKP nespremenjen, položajno izboljšani podatki pa so vključeni v ZKN, pri čemer se je obstoječi ZKN (pred lokacijsko izboljšavo) dopolnil s podatki izboljšanega ZKP in tako postal zvezen grafični podatkovni sloj, ki se že uporablja v procesih geodetske uprave, kjer se podatki nepremičninskih evidenc določajo na podlagi grafičnih presekov (na primer dejanska raba zemljišč, boniteta zemljišč), v projektu množičnega zajema poseljenih zemljišč (podlaga za vzpostavitev evidence stavbnih zemljišč), v projektu zajema dejanske rabe zemljišč infrastrukturnih objektov (ceste, železnice), kot podlaga v različnih GIS-okoljih. Zapisał: Franc Ravnihar, za Geodetsko upravo RS e-naslov: franc.ravnihar@gov.si PREDLOG ZAKONA O KATASTRU NEPREMICNIN Ministrstvo za okolje in prostor je konec leta 2019 opravilo medresorsko obravnavo osnutka Zakona o katastru nepremičnin, ki ga je pripravila Geodetska uprava Republike Slovenije.
In this paper we present a description of a new multispectral airborne mapping light detection and ranging (lidar) along with performance results obtained from two years of data collection and test ...campaigns. The Titan multiwave lidar is manufactured by Teledyne Optech Inc. (Toronto, ON, Canada) and emits laser pulses in the 1550, 1064 and 532 nm wavelengths simultaneously through a single oscillating mirror scanner at pulse repetition frequencies (PRF) that range from 50 to 300 kHz per wavelength (max combined PRF of 900 kHz). The Titan system can perform simultaneous mapping in terrestrial and very shallow water environments and its multispectral capability enables new applications, such as the production of false color active imagery derived from the lidar return intensities and the automated classification of target and land covers. Field tests and mapping projects performed over the past two years demonstrate capabilities to classify five land covers in urban environments with an accuracy of 90%, map bathymetry under more than 15 m of water, and map thick vegetation canopies at sub-meter vertical resolutions. In addition to its multispectral and performance characteristics, the Titan system is designed with several redundancies and diversity schemes that have proven to be beneficial for both operations and the improvement of data quality.
•Horizontal LIDAR performance assessed via comparative study without experiment data.•Atmosphere model employed real visibility data and MODTRAN® solar spectral radiance.•Shiina LIDAR had better ...range resolution but inferior maximum detection range.•VAST LIDAR had superior detection and signal quality but very poor laser safety.•Hypothetical setup showed more balanced performance and met case study requirements.
LIDAR performance is often evaluated after assembled prototypes are deployed for field tests. However, this approach is resource-intensive, which necessitates more cost-effective ways to detect flaws and improve LIDAR design. In this work, we present numerical assessment of horizontal scanning LIDAR performance via comparative study method. This assessment method could evaluate LIDAR performance without physically assembling the unit, hence save resources and time. We demonstrate this using a hypothetical atmospheric LIDAR. In our assessment, Python™ was used to develop simulation algorithm based on LIDAR equation, while Koschmieder visibility theory was used in atmosphere modeling. Daytime visibility and MODTRAN® solar spectral radiance data were also incorporated for analysis. We then evaluated LIDAR performance based on signal-to-noise and range-corrected signal profiles. Lastly, we conducted comparative study of this hypothetical LIDAR setup with Shiina (light emitting diode) LIDAR and VAST (ground-based) LIDAR for horizontal distance of 1 km. Numerical analysis showed that hypothetical LIDAR could operate up to 1 km at night. During daytime, detection was limited to 94 m and 220 m for 532 nm and 808 nm channels respectively. Comparative study demonstrated that the hypothetical LIDAR excelled in nighttime detection range with acceptable daytime performance. Overall, the hypothetical LIDAR has met case study requirements. We demonstrate the feasibility of this numerical assessment via comparative study method by identifying possible improvements in laser module without experimental data verification.
Impacts of small‐scale surface irregularities, or surface roughness, of atmospheric ice crystals on lidar backscattering properties are quantified. Geometric ice crystal models with various degrees ...of surface roughness and state‐of‐the‐science light‐scattering computational capabilities are utilized to simulate the single‐scattering properties across the entire practical size parameter range. The simulated bulk lidar and depolarization ratios of polydisperse ice crystals at wavelength 532 nm are strongly sensitive to the degree of surface roughness. Comparisons of these quantities between the theoretical simulations and counterparts inferred from spaceborne lidar observations for cold cirrus clouds suggest a typical surface‐roughness‐degree range of 0.03–0.15 in the cases of compact hexagonal ice crystals, which is most consistent with direct measurements of scanning electron microscopic images. To properly interpret lidar backscattering observations of ice clouds, it is necessary to account for the degree of surface roughness in light‐scattering computations involving ice crystals.
Plain Language Summary
Lidar (Light Detection and Ranging) instruments on satellites use reflected, or backscattered, laser beams to investigate ice clouds in the atmosphere. However, it has long been a challenge to interpret lidar signals, called backscattering properties, to infer ice cloud characteristics accurately. This study uses theoretical simulations to investigate how small‐scale surface irregularities of ice crystals affect the lidar signals associated with ice clouds. These simulations demonstrate the significant impacts of small‐scale surface irregularities of ice crystals on backscattering. Based on comparisons between the theoretical simulations and satellite lidar observations, it is necessary to assume a moderate degree of small‐scale surface irregularities to explain lidar observations of typical ice clouds.
Key Points
The sensitivity of the backscattering properties to the surface roughness of atmospheric ice crystals is theoretically investigated
The depolarization ratio is substantially sensitive to the degree of surface roughness of ice crystals
Compact hexagonal ice models with degrees of surface roughness ranging 0.03–0.15 reasonably explain the Cloud‐Aerosol Lidar with Orthogonal Polarization backscattering signals
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