Dissertations / Theses: 'Laser altimeters'

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Filin, Sagi. "Calibration of Airborne and Spaceborne Laser Altimeters Using Natural Surfaces." The Ohio State University, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=osu1381146808.

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Farrell, S. L. "Satellite laser altimetry over sea ice." Thesis, University College London (University of London), 2006. http://discovery.ucl.ac.uk/1445477/.

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The Arctic region plays an important role in the global climate system through various feedbacks, involving surface albedo, oceanic deep-water formation, and sea surface salinity, which can amplify climate variability and change. We investigate the exploitation of data collected by the first Earth-orbiting laser altimeter carried onboard ICESat over the sea-ice covered regions of the Arctic Ocean. We extract parameters associated with the study of the polar climate system including the time-varying component of sea surface topography and sea ice freeboard. We assess an existing method for the retrieval of Arctic sea surface height from ICESat data. We present an alternative method for sea surface height retrieval, based on surface reflectivity and analysis of parameters associated with the shape of the received echo. This method aims to discriminate echoes originating over leads or thin ice. We provide the first maps of Arctic sea surface height as derived from ICESat. We examine the accuracy of our results through comparisons with independent sea surface height estimates derived from ENVISAT radar altimetry. We demonstrate the use of sea surface height data for oceanographic and geodetic applications in the Arctic Ocean. We derive an ICESat mean sea surface which, when combined with the recently developed Arctic hybrid geoid model, can be used to analyse mean dynamic ocean topography. In addition we investigate the use of ICESat sea surface height measurements to map marine gravity anomalies up to the limit of coverage at 86 N. By combining ICESat surface elevation measurements with sea surface height estimates, we derive sea ice freeboard throughout the Arctic up to 86 N. We compare our results to coincident estimates of sea ice freeboard from ENVISAT. Finally, we explore the feasibility of combining satellite laser and radar altimetric measurements of sea ice freeboard to measure the depth of snow loading on sea ice.

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Giles, Katharine Anne. "Radar and laser altimeter measurements over Arctic sea ice." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1445518/.

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To validate sea ice models, basin wide sea ice thickness measurements with an accuracy of 0.5 m are required to analyse trends in sea ice thickness, it is necessary to detect changes in sea ice thickness of 4 cm per year on a basin wide scale. The estimated error on satellite radar altimeter estimates of sea ice thickness is 0.45 m and the estimated error on satellite laser altimetry estimates of sea ice thickness is 0.78 m. The Laser Radar Altimetry (LaRA) field campaign took place in the Arctic during 2002. It was the first experiment to collect coincident radar and laser altimetry over sea ice. This thesis analyses the data from LaRA to explore the potential of combining radar and laser altimetry to reduce the uncertainties in measurements of sea ice thickness. Two new methods to analyse the LaRA data are described. The first is the University College London (UCL) Delay/Doppler radar altimeter (D2P) re-tracking algorithm and the second is the UCL D2P power simulator. Each method is calibrated and the associated error is estimated. The UCL D2P power simulator reproduces the D2P returns closely, and is used to estimate the elevation difference between the reflecting surface of the radar and the laser with an accuracy of 0.07 m. The laser is shown to consistently reflect from a higher surface than the radar. The offset between the laser and the radar is consistent with observed snow depths and compares well to snow depth distributions from in-situ data. We find that reducing the error in snow depth to 7 cm reduces the radar error in sea ice thickness from 0.45 m to 0.37 m and the laser error in sea ice thickness from 0.78 m to 0.55 m.

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Quinn, Katherine J. (Katherine Jane) 1971. "Atmospheric delay modeling for satellite laser altimetry." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8061.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2002.
Includes bibliographical references.
NASA's Ice, Cloud, and Land Elevation Satellite (ICESat) is a laser altimetry mission with the primary purpose of measuring the mass balance of the ice sheets of Greenland and Antarctica. It will provide 5 years of topography measurements of the ice, as well as land and ocean topography. In order to accurate topography measurements the laser altimeter ranges must be corrected for certain biases. Atmospheric delay is one such bias. As the laser pulse travels through the atmosphere it will be refracted, introducing a delay into the travel time. This delay must be estimated to correct the ranges and the delay estimations need to be validated. Of particular concern are errors in the delay estimates that have the same characteristics as the expected mass balance variations. The main focus of this dissertation is to formulate algorithms for calculating the ICE-Sat atmospheric delay and estimate the expected delay values and errors. Our atmospheric delay algorithm uses numerical weather model data to estimate delay values. We have validated these algorithms using Automatic Weather Stations (AWS) in the polar regions and GPS data over the globe. The GPS data validation was also augmented by in-situ meteorology measurements at some the stations. The GPS validation process additionally allowed us to investigate the estimation of precipitable water vapor using GPS data. The validation studies have shown that our atmospheric delay algorithm errors are well within the ICESat error budget of 20 mm. The overall global delay errors are estimated to be approximately 5.4 mm and the polar delay errors are 12.2 mm. There are no discernible biases in the error and the seasonal variations in error magnitudes are well characterized.
by Katherine J. Quinn.
Ph.D.

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Rosette, Jacqueline. "Biophysical parameter retrieval from satellite laser altimetry." Thesis, Swansea University, 2009. https://cronfa.swan.ac.uk/Record/cronfa42348.

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Quantifying and monitoring vegetation distribution and change are fundamental to carbon accounting and requirements of national forest inventories. This research explores the potential of the Geoscience Laser Altimeter System (GLAS), launched in 2003 by NASA as the first global Earth surface satellite LiDAR mission. The project study site is the Forest of Dean, Gloucestershire, UK, a highly mixed, temperate forest with varied topography. Methods are developed to distinguish the regions within waveforms returned from vegetation and ground. When compared with field measurements, estimation of canopy height gives a correlation of R2=0.92; RMSE=2.81m. Waveform indices are determined and evaluated with respect to their potential to estimate biophysical parameters. Heights of cumulative energy percentiles within the waveform prove to be significant estimators. When compared to calculations from independent yield models, results show correlations with stand- level top height (R2=0.76; RMSE 3.9m) and stemwood volume (mixed composition stands dominated by broadleaves: R2=0.47, RMSE=75.6m3/ha; conifers: R2=0.66, RMSE=82.5m3/ha). Uncertainty analysis is undertaken of both waveform and yield model estimates. Canopy cover is estimated for the area beneath GLAS waveforms, corrected for differences in reflectance for ground and canopy surfaces. These are assessed against airborne LiDAR estimates, validated using hemispherical photography. The method produces results with R2=0.63; RMSE=11% for stands with greatest coverage by broadleaves and R2=0.41; RMSE 16% for conifer-dominated stands. Small footprint airborne LiDAR (AL) is widely accepted to offer valuable data regarding forest parameters. An evaluation of AL and GLAS results demonstrate that the broad GLAS footprint dimensions allow similar estimation of stand-level parameters (e.g. AL/yield model Top Height: R2=0.73, RMSE=4.5m). Direct comparison of GLAS with AL shows ground surface identification with mean difference of 0.32m and that elevation profiles correspond well (98th percentiles R2=0.76, RMSE=3.4m). Finally, prospects for use of LiDAR in carbon accounting, assimilation within models and for forestry applications are discussed.

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Magruder, Lori Adrian. "Pointing angle and timing verification of the geoscience laser altimeter using a ground-based detection system." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3037523.

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Rothwell, Derek A. "Precise orbit determination and analysis from satellite altimetry and laser ranging." Thesis, Aston University, 1989. http://publications.aston.ac.uk/10662/.

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For optimum utilization of satellite-borne instrumentation, it is necessary to know precisely the orbital position of the spacecraft. The aim of this thesis is therefore two-fold - firstly to derive precise orbits with particular emphasis placed on the altimetric satellite SEASAT and secondly, to utilize the precise orbits, to improve upon atmospheric density determinations for satellite drag modelling purposes. Part one of the thesis, on precise orbit determinations, is particularly concerned with the tracking data - satellite laser ranging, altimetry and crossover height differences - and how this data can be used to analyse errors in the orbit, the geoid and sea-surface topography. The outcome of this analysis is the determination of a low degree and order model for sea surface topography. Part two, on the other hand, mainly concentrates on using the laser data to analyse and improve upon current atmospheric density models. In particular, the modelling of density changes associated with geomagnetic disturbances comes under scrutiny in this section. By introducing persistence modelling of a geomagnetic event and solving for certain geomagnetic parameters, a new density model is derived which performs significantly better than the state-of-the-art models over periods of severe geomagnetic storms at SEASAT heights. This is independently verified by application of the derived model to STARLETTE orbit determinations.

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Koch, Christian. "Extraction of Mercury's tidal signal and libration amplitude from synthetic laser altimeter data sets." [Göttingen] Copernicus Publ, 2009. http://d-nb.info/999293885/04.

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Cobby, David Mark. "The use of airborne scanning laser altimetry for improved river flood prediction." Thesis, University of Reading, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394019.

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Airborne scanning laser altimetry (LiDAR) is an important new data source for many environmental applications, mapping topographic and surface object height to high vertical (±15-20cm) and horizontal (±30-100cm) accuracy over large areas, both time and cost effectively. These data offer improvements in 2D hydraulic flood models by providing floodplain bathymetry and vegetation height for the parameterisation of friction. Current parameterisations use one (temporally constant) value of friction for the floodplain, and one for the channel, with these values determined through a calibration procedure which limits the physical basis of the model and, hence, its applicability to different catchments and flood events. Primarily for this reason, a LiDAR data processing system is developed that segments a rural scene into water and three vegetation height classes. The vegetation and topographic heights in each class are calculated, and are accurate to ±14cm and ±17cm (respectively) for the class 'crops and grasses'. The vegetation heights are subsequently converted. using existing empirical equations, into friction coefficients that vary with the local flow depth and velocity. This friction parameterisation is implemented in the TELEMAC-2D model and a Hood that occurred on the river Severn in 1998 is simulated. When compared with a Synthetic Aperture Radar (SAR) image of the event, the model accurately predicts the inundation extent. The LiDAR vegetation segmentation is also used to drive a new mesh generator which decomposes the mesh around automatically identified vegetation features so t.hat. regions of abruptly changing boundary friction (and, as it. transpires, topographic gradient) are represented more explicitly in t.he model. Further model simulations demonstrate (i) an improvement in inundation extent prediction using the spatiotemporally variable friction parameterisation on the decomposed mesh, and (ii) variations in predicted velocities which may be observable using remote sensing. Indeed. velocity patterns are identified as important in model validation as the SAR data exhibit inadequacies.

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Chen, Gang 1965. "GPS kinematic positioning for the airborne laser altimetry at Long Valley, California." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9680.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, February 1999.
Includes bibliographical references.
The object of this thesis is to develop a reliable algorithm and software for em-level kinematic GPS (Global Positioning System) data analysis. To assess the accuracy of the software, we use it to determine the trajectory of the aircraft during the surveys at Long Valley, California, in 1993 and 1995. This thesis covers the algorithm development, the modeling, and the software design. We implement a robust Kalman filter to perform the kinematic data processing for GPS measurements. In the kinematic data processing with the Kalman filter, the estimates of the aircraft's position, the GPS receiver clock, and atmospheric corrections are modeled with appropriate stochastic processes. To achieve em-level accuracy for an aircraft trajectory, the GPS phase observables must be used and the integer-cycles of phase ambiguity must be resolved. In this thesis, we investigate the ambiguity problem in different situations and develop different ambiguity strategies depending on the situation. Firstly, we develop a position-independent (position-free) ambiguity search method for the initial ambiguity search for GPS kinematic surveying. Our ambiguity search method focuses on providing the flexibility and uniqueness to determine the correct ambiguities in most experimental conditions including long baselines (up to 100 km), high noise level in low elevation observations, and "bad" observations during the search. Secondly, we develop a method to utilize position-free wide lane and extra wide lane observables to detect cycle slips that occur when the signal from a GPS satellite is interrupted during the flight, for example, when the satellite is blocked by the aircraft's wing during a turn. Our ambiguity algorithms use dual frequency GPS observables so that the effects of the ionospheric delay can be accounted for. Several tests performed indicate that our ambiguity strategy works well for a separation between the moving and fixed GPS receivers of up to 100 lan. We developed a killematic software developed to automatically detect various errors during the data processing, including detecting and correcting of cycle slips, detecting and removal of bad data, and performing ambiguity searches. The user interface to the software is command driven with default values for most processing. This interface provides flexibility and should make the software usable with little training. To evaluate our software, we processed GPS data taken in the 1993 and 1995 Long Valley airborne laser altimetry surveys. We performed four types of tests: (a) Static tests which the evaluate the root-mean-square (RMS) scatter of the aircraft position while it is stationary on the run-way; (b) runway tests which compare the height estimates of the aircraft at approximately the same position along the runway during taxiing, takeoffs and landings; (c) lake tests in which we compare profiles of Lake Crowley"s surface and crossings on the lake surface; and (d) Benton crossing tests in which we compare surface height estimates at location within 2 m of each other at a grassy region of Benton Crossing. The latter two tests use of combination of the laser altimeter and GPS trajectory data. The processing of the laser data with our GPS trajectory was performed by our colleagues at the Scripps Institute of Oceanography. The static tests show that during the times the aircraft was stationary at the beginning and ends of flights, the R..MS scatter of relative height difference between the aircraft and the reference GPS station at Bishop airport, approximately 500 meters from the aircraft, varied between 4 and 2 mm for both campaigns. The One Way tests show that the average height differences between trajectories repeat to within 4 em for six tracks on the taxiway, during the takeoffs and landings. The lake surface tests show height variations within 3 em for the lake surface after removing the cubic polynomial to approximately fit for the geoid-ellipsoidal height differences and flow within the lake for each of the five flight sections over the lake. The Lake Crowley crossover analysis shows a mean difference of 0.2 em and RMS scatter of 4.5 cm for relative height from laser footprint pairs within 2 m distance. The Benton Crossing crossover results show a mean value of 0.2 cm and RMS scatters of 15.5 cm in a similar cross analysis after outliers are deleted. Based on our analyses, we conclude that laser altimetry over the flat surface (i.e. Lake Crowley) can denning surface heights with -3 cm precision. The contribution from the error in GPS trajectory appears to be 1-2 cm.
by Gang Chen.
Ph.D.

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Ashworth, Andrew Lee. "Predicting Southeastern forest canopy heights and fire fuel models using Geoscience Laser Altimeter System data." Master's thesis, Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-05102008-141659.

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Talpe, Matthieu Jean. "Investigation of regional variation in Lunar crater morphometry from (Lunar Orbiter Laser Altimeter) LOLA observations." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/114358.

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Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 41-42).
The advent of global Digital Elevation Models of the lunar surface, obtained from the Lunar Orbiter Laser Altimeter (LOLA), has allowed for a quantitative assessment of crater morphometry. 351 simple and complex craters in the Mare Serenitatis, far side highlands, near side highlands, and South Pole-Aitken basin are decomposed into 50 elevation profiles, from which key geometric crater properties are extracted. The geometric properties and their respective standard variation, such as height-to-diameter ratios, and average elevation profile are compared on a global level to investigate regional differences in terrain rheology and study the transition between the simple and complex crater regime. Furthermore, the relationship between known degradation mechanisms and crater morphometry is discussed, as well as the current state of quantitative methods to assess crater degradation. The resulting regional differences observed in crater morphometry are explained in the context of lunar geologic history. Finally, the addition of other crater geometric properties in future quantitative assessments will broaden the study of crater morphometry, and improvements to current methods are necessary to conclusively define degradation states in terms of quantitative factors.
by Matthieu Jean Talpe.
S.B.

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Vrancken, Patrick. "Characterization of T2L2 (Time Transfer by Laser Link) on the Jason 2 ocean altimetry satellite and Micrometric laser ranging." Phd thesis, Université de Nice Sophia-Antipolis, 2008. http://tel.archives-ouvertes.fr/tel-00367703.

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Le schéma de T2L2 (Transfert de Temps par Lien Laser), basé sur la technologie de la télémétrie laser (SLR), représente un nouveau moyen pour la synchronisation d'horloges distantes. L'expérience T2L2 fut acceptée par le CNES en 2005 d'être embarqué sur le satellite d'altimétrie des mers Jason 2.
La première partie de ce travail traite la caractérisation intégrale de l'instrument spatial T2L2, incluant la calibration et l'évaluation de sa performance en métrologie de temps/fréquence. Ces tests furent menée à l'aide d'un banc de test de haute complexité, développé à l'Observatoire de la Côte d'Azur.
Par ailleurs, le document décrit un bilan des performances du schéma intégrale T2L2, incluant l'instrument spatial ainsi que le segment sol et autres contributeurs ; par conséquent on démontre la performance finale de tout le transfert de temps: Avec une stabilité de quelques picosecondes en intégrant pendant un passage du satellite, T2L2 permettra de comparer les horloges les plus avancés, incluant les fontaines atomiques. L'exactitude absolue d'un transfert de temps fut déterminé à moins que 50 ps en configuration vue commune.

La deuxième partie du document présent est orientée autour l'extension de la technologie de télémétrie laser et T2L2 à la mesure absolue et de très haute résolution de distances en espace.
Cet objectif devra être atteint en utilisant un laser de peigne de fréquences en combinant la mesure de temps de vol avec une mesure interférométrique.
Le document décrit un pas important vers la faisabilité de cet approche, la mesure de distances en datation à très haute cadence et en mesure de phase, ce qui devrait permettre de franchir le seuil de la longueur d'onde.

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Poole, W. D. B. "Deriving planetary surface characteristics from orbiting laser altimeter pulse-widths on Mars, the Moon, and Earth." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1469361/.

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A set of equations linking the time-spread of a laser altimeter echo-profile, commonly known as the pulse-width, to the variance of topography within the pulse-footprint are tested by comparing pulse-width data to surface characteristics measured from high-resolution Digital Terrain Models. The research is motivated by the advent of high-resolution Digital Terrain Models over Mars, which enables the calibration of Mars Orbiter Laser Altimeter pulse-widths, and evolves to include lunar and terrestrial data in an attempt to validate the theory and develop new methods. Analysis of Mars Orbiter Laser Altimeter pulse-width data reveals mixed results. Over homo- geneously rough terrain, at kilometre-scales, these pulse-widths show some correlation to surface characteristics, once poor pulse data has been removed. However, where roughness is highly vari- able over short baselines, little correlation is observed, which is attributed to a mix of georeferencing errors and instrument methods. In a similar study, Lunar Orbiter Laser Altimeter pulse-widths are shown to produce only poor correlations with surface characteristics over local study sites. Instead, the observed correlations differ from orbit to orbit, with the majority of those used appearing to contain poor quality pulse- width data - attributed to the instrument methods - and only 14 % revealing correlations similar, or better, than observed over Mars. Finally, an examination of the relationship between footprint-scale surface characteristics and pulse-width estimates derived from smoothed Ice, Cloud, and land Elevation Satellite echo-profiles enables different pulse-width thresholds to be tested. Here, pulse-widths measured using a 10 % Peak Energy threshold are shown to produce greater correlations than those observed using the Mars Orbiter Laser Altimeter and the Lunar Orbiter Laser Altimeter data, which use a Full Width Half Maximum threshold. To conclude, pulse-widths can show strong correlations to surface roughness and slope within the pulse-footprint. However the assumption that detrended surface roughness can be derived by applying a slope contribution effect is shown to be unfounded. The principal recommendation is for future instruments to use a full echo-profile in estimating pulse-width values at a 10 % Peak Energy threshold, providing both efficient noise removal and a better correlated dataset.

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Shu, Song. "Satellite Radar and Laser Altimetry for Monitoring of Lake Water Level and Snow Accumulation in Arctic Regions." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1561394321584998.

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Nelson, Ross. "The use of airborne laser altimetry to estimate tropical forest basal area, volume, and biomass." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/37262.

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Khalefa, Ehsan Fayez. "Remote sensing of savannah vegetation structure using the geoscience laser altimeter system and L-band synthetic aperture radar." Thesis, University of Leicester, 2012. http://hdl.handle.net/2381/10992.

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Savannahs are globally important but not well understood systems. They consist of the coexistence of trees and grasses. A major challenge in savannah ecosystems studies is the need of maps of vegetation structure over large areas where the field data collection is impractical and time consuming. Active remote sensing such as spaceborne LiDAR and RADAR has experienced limited use in these complex heterogeneously vegetated systems. This thesis examines the ability of spaceborne ICESat-GLAS data to retrieve vegetation parameters from these more structurally and sparsely complex vegetated ecosystems. For this main purpose, two methods of retrieving savannah vegetation heights from GLAS data were explored based on Gaussian decomposition. Results showed that the direct method works well over flat areas (R=0.63 and RMSE=1.32m; R=0.68and RMSE=2.61m; n=12) for GLA01 and GLA14 respectively, while sloped areas need statistical methods to remove the effect of terrain slopes on the waveform extent for better estimation of maximum vegetation height (R²=0.78 and RMSE =14.5m; R²=0.67 and RMSE=17.5m; n=6) for using terrain index and waveform width as a terrain correction factor in regression models. This work has compared the estimation of vegetation parameters derived from airborne LiDAR data and field measured data with results from spaceborne GLAS LiDAR data. GLAS estimated stand density produced R=0.98 with those estimated from airborne LiDAR data. Moreover, GLAS ratio which related to the amount of woody cover in each footprint shows a strong relationship with those extracted from LiDAR airborne data (R=0.93) and also presents a good correlation (R=0.85) when compared with woody cover field observations. In addition, ALOS PALSAR RADAR data was used to evaluate the results of estimating woody cover from GLAS LiDAR waveform parameters in another site at the Kruger National Park. This comparison showed a significant correlation between GLAS estimated woody cover and ALOS L-band HH backscatter (R=0.59). This work provides an important source of knowledge for the South Africa National Parks (SANParks) Authority with a powerful tool for an adequate spatially-consistent monitoring and assessment of the woody vegetation structure of savannah landscapes.

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Ridgway, Jeffrey R. "The development of a deep-towed gravity meter, and its use in marine geophysical surveys of offshore Southern California and an airborn laser altimeter survey of Long Valley, California /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1997. http://wwwlib.umi.com/cr/ucsd/fullcit?p9907824.

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Ferraz, Rodrigo da Silva. "Avaliação posicional de dados altimétricos gerados por diferentes sistemas de varredura a laser terrestre: estudo de caso." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/164378.

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As utilizações de dados altimétricos, nesse estudo analisados a partir de modelos digitais de terreno (MDT), são as mais variadas assim como as técnicas de obtenção desse tipo de dado. Pode-se obter MDT por radar de abertura sintética que é utilizado para o levantamento de grandes áreas e de difícil acesso. Também pode-se gerar esse tipo de dado por Fotogrametria, por Topografia utilizando estação total com apoio GNSS (Global Navigation Satellite System). Uma tecnologia mais atual para a obtenção de dados altimétricos é a utilização de tecnologia Lidar (light detection and ranging) que consiste na medição de distância e coordenadas através de um pulso eletromagnético que interage com os alvos. O produto básico dos sistemas que utilizam a tecnologia Lidar, seja em plataformas aéreas ou terrestres, é denominado de nuvem de pontos. Essas nuvens de pontos possuem coordenadas tridimensionais (X, Y e Z) referenciadas ao centro de fase do sensor. Nesse estudo foram realizados experimentos com dois sistemas de varredura a laser terrestre. O primeiro é um sistema de varredura modelo Optech Ilris 3D e outro Faro Focus 3D, nesse estudo denominados de SVLT Optech e SVLT Faro. Assim, o objetivo desse trabalho é estimar a qualidade posicional dos dados altimétricos gerados por dois SVLT. Os estudos foram executados em dois experimentos. No primeiro experimento foram realizados escaneamentos num campo de calibração. Nessa etapa foi gerada uma nuvem de pontos de cada sistema de varredura, e esses dados foram georreferenciados e a partir de pontos de checagem medidos no mesmo e assim foi estimada o controle de qualidade posicional. No segundo experimento, os dois SVLT foram utilizados para efetuar um levantamento topográfico planialtimétrico em um percurso de aproximadamente um quilômetro. Os dados gerados pelos SVLT passaram por um processo de registro, que consiste na junção de pares de nuvens de pontos, e foram georreferenciados a partir de pontos de controle medidos no terreno. Nesse percurso foram realizados circuitos de nivelamento cujos vértices foram utilizados para se estimar o controle de qualidade posicional, planimétrico e altimétrico, das nuvens de pontos oriundas dos dois sistemas de varredura. Assim, após a realização de testes estatísticos, no primeiro experimento, obteve-se valores de acurácia altimétrica de 1,5 cm para o SVLT Faro e de 1,3cm para o SVLT Optech e no segundo experimento acurácia altimétrica de 1,9 cm para o SVLT Faro e de 5,9 cm para o SVLT Optech.
The uses of altimetric data, in this study approached from digital terrain models (TDM) are the most varied as well as the techniques for getting this type of data. It can be get DTM by synthetic aperture radar that is used for surveying wide areas and with difficult access. As well it can be this type of data by Photogrammetry, by conventional Topography using total station with GNSS (Global Navigation Satellite System) support. A more actual technology for obtaining altimetric data is the use of light detection and ranging technology, which consists of measuring distance and coordinates through an electromagnetic pulse that interacts with the targets. The basic product of the systems that use the technology lidar, be it in aerial or terrestrial platforms, is denominated a point cloud. These point clouds have three-dimensional coordinates (X, Y, and Z) referenced to phase center of the sensor. In this study, will be performed experiments with two systems of terrestrial laser scanning (STLS). One STLS of the brand Optech Ilris 3D and another of the brand Faro Focus 3D, in this study called of STLS Faro and STLS Optech. Therefore, the aim of this work is to estimate the positional quality of digital terrain models generated by these two STLS. The studies were executed in two experiments. In the first experiment, scans has been made on a calibration wall. The generated point clouds were georeferenced and from the checkpoints measured in this calibration wall, the positional quality of these data was estimated. In the second experiment, the two STLS were has been made a planialtimetric topographic survey of a course of approximately one kilometer. In this course a leveling network was created and the vertices of this network were used to estimate the positional quality control of the points clouds from the two STLS. Therefore, after realization statistical tests, in the first experiment, it was obtained altimetric accuracy values of 1.5 cm for the STLS Faro and 1.3 cm for the STLS Optech were obtained and in the second experiment, the altimeter accuracy of 1.9 cm for the STLS Faro and 5.9 cm for the Optech STLS.

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Stark, Alexander [Verfasser], Jürgen [Akademischer Betreuer] Oberst, Hauke [Akademischer Betreuer] Hussmann, Jürgen [Gutachter] Oberst, Steven A. [Gutachter] Hauck, and Nicolas [Gutachter] Thomas. "Observations of Mercury's rotational state from combined MESSENGER laser altimeter and image data / Alexander Stark ; Gutachter: Jürgen Oberst, Steven A. Hauck, Nicolas Thomas ; Jürgen Oberst, Hauke Hussmann." Berlin : Technische Universität Berlin, 2015. http://d-nb.info/115633358X/34.

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Thor, Robin N. [Verfasser], Ulrich R. [Akademischer Betreuer] Christensen, Jürgen [Akademischer Betreuer] Oberst, Reinald [Akademischer Betreuer] Kallenbach, Jürgen [Gutachter] Oberst, and Agnès [Gutachter] Fienga. "Extracting tides from laser altimetry observations: a global approach / Robin N. Thor ; Gutachter: Jürgen Oberst, Agnès Fienga ; Ulrich R. Christensen, Jürgen Oberst, Reinald Kallenbach." Berlin : Technische Universität Berlin, 2020. http://d-nb.info/1219573892/34.

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Steinbrügge, Gregor [Verfasser], Jürgen [Akademischer Betreuer] Oberst, Jürgen [Gutachter] Oberst, Nicolas [Gutachter] Thomas, and Tilman [Gutachter] Spohn. "Tidal deformation of planets and satellites : Models and methods for laser- and radar altimetry / Gregor Steinbrügge ; Gutachter: Jürgen Oberst, Nicolas Thomas, Tilman Spohn ; Betreuer: Jürgen Oberst." Berlin : Technische Universität Berlin, 2018. http://d-nb.info/1161799486/34.

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Göbell, Sibylle. "Determination of sea ice surface elevation with laser and radar altimetry and comparison with ice thickness data sets in the Arctic and Antarctic = Bestimmung der Oberflächenhöhe von Meereis mit Laser- und Radaraltimetrie und Vergleich mit Eisdickendatensätzen in der Arktis und Antarktis /." Bremerhaven : Alfred-Wegener-Institut für Polar- und Meeresforschung, 2007. http://www.loc.gov/catdir/toc/fy0803/2008365359.html.

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Wheelock-Davis, Emily J. "Elevation Changes in Greenland over Two Decades from Cross-Platform LIDAR Analysis." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366223499.

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Gläser, Philipp [Verfasser], Jürgen [Akademischer Betreuer] Oberst, Gregory [Akademischer Betreuer] Neumann, and Harald [Akademischer Betreuer] Hiesinger. "Evaluation of topography, slopes, illumination and surface roughness of landing sites near the lunar south pole using laser altimetry from the lunar reconnaissance orbiter / Philipp Gläser. Gutachter: Jürgen Oberst ; Gregory Neumann ; Harald Hiesinger. Betreuer: Jürgen Oberst." Berlin : Technische Universität Berlin, 2014. http://d-nb.info/1067388044/34.

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Gläser, Philipp Andreas [Verfasser], Jürgen [Akademischer Betreuer] Oberst, Gregory [Akademischer Betreuer] Neumann, and Harald [Akademischer Betreuer] Hiesinger. "Evaluation of topography, slopes, illumination and surface roughness of landing sites near the lunar south pole using laser altimetry from the lunar reconnaissance orbiter / Philipp Gläser. Gutachter: Jürgen Oberst ; Gregory Neumann ; Harald Hiesinger. Betreuer: Jürgen Oberst." Berlin : Technische Universität Berlin, 2014. http://d-nb.info/1067388044/34.

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Gilio, Joseph Paul. "Initial development of a laser altimeter." Thesis, 1985. http://hdl.handle.net/10945/21384.

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Magruder, Lori Adrian 1971. "Pointing angle and timing verification of the geoscience laser altimeter using a ground-based detection system." 2001. http://hdl.handle.net/2152/10730.

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Yu-LingTai and 戴郁伶. "Geocenter Variation derived by Satellite Laser Ranging and Satellite Altimetry." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/68046383921408366435.

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碩士
國立成功大學
測量及空間資訊學系碩博士班
101
Geocenter variation is defined as the displacement of the Earth’s center of mass (CM) relative to its center of figure (CF) and is generally represented as the temporal variations of degree 1 geopotential coefficients. Because geocenter variation results from the mass redistribution within the earth system, it can be accurately determined if mass changes on the Earth are well known. In the present study, SLR and GRACE gravity field solutions combining with steric-corrected altimetry are used to calculate the geocenter motions by the algorithm from Swenson et al. [2008] and the iteration algorithm. The results computed by the iteration algorithm agree well with those by the algorithm from Swenson et al. [2008] and even have higher precisions. The results derived from SLR and GRACE solutions combining with steric-corrected altimetry data are consistent, indicating that not only GRACE data but also SLR geopotential solutions be used to estimate geocenter motions. The mass variations computed using the estimated degree 1 coefficients from GRACE combining with higher degree-order coefficients agree better with the steric-corrected altimetry measurements than from SLR; however, the SLR-estimated geocenter motions cover a longer time span starting from 1993. Finally, the SLR-derived geocenter motions and GRACE gravity solutions were combined to calculate the mass changes. The results show that the differences of the computed mass variations can change up to 50% of total mass changes in amplitudes when the estimated geocenter motions were used. The ice sheets in Greenland and Antarctica are melting at the rates of -85.38 ± 1.26 mm/yr and -10.54 ± 0.55 mm/yr, respectively, and global ocean mass variations (within latitude ±66o) is rising at a rate of 0.72 ± 0.15 mm/yr.The ocean mass in the Caspian Sea is also decreasing at a rate of -16.61±1.37 mm/yr because of less river discharge.

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Leigh, Holly Wallis. "Development of onboard digital elevation and relief databases for the advanced topographic laser altimeter system." Thesis, 2013. http://hdl.handle.net/2152/23681.

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The Ice, Cloud, and land Satellite-2 (ICESat-2) is planned to launch in 2016 carrying the Advanced Topographic Laser Altimeter System (ATLAS). ATLAS will be the first space-based photon-counting laser altimeter to be put into operation, and is tasked with observing the Earth’s ice sheets, sea ice, and vegetation. The environment in which ATLAS will be operating is expected to introduce a significant amount of noise into the received signal; this necessitates that a set of onboard Receiver Algorithms be developed to reduce the data volume and data rate to acceptable levels while still transmitting the relevant ranging data. The algorithms make use of signal processing techniques, along with three databases, the Digital Elevation Model (DEM), the Digital Relief Map (DRM), and the Surface Reference Mask (SRM), to find the signal and determine the appropriate dynamic range of vertical data surrounding the surface for downlink. The focus of this study is the development of the DEM and DRM databases. A number of elevation data sets are examined for use as inputs for the databases. No global data sets of sufficient quality and resolution are available for the development of the project, so best-available regional elevation data sets were selected instead. Software was developed in MATLAB to produce the DEM and DRM data bases from the input data sets. A method for calculating relief from a gridded elevation data set along the flight path of a satellite was developed for the generation of relief maps used to create the DRM. Global DEM and DRM databases were produced by mosaicking individual DEM and DRM tiles from each input data set into global grids. A technique was developed to determine the accuracy of the DRM by using ICESat ground elevations to evaluate the accuracy of an input elevation data set. By comparing values of DRM accuracy to values of DRM relief, estimates of DRM accuracy as a function of relief magnitude were determined and used to define values of DRM padding in the receiver algorithm.
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Silva, Bruno Miguel Pereira da. "A computational softwre tool for satellite laser altimetry data processing. Analysis and visualisation." Master's thesis, 2021. http://hdl.handle.net/10400.13/3562.

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NASA’s Ice, Cloud, and Land Elevation Satellite (ICESat), the first global laser altimetry satellite, was operated between 2003 and 2009 with the primary mission objective of measuring Earth’s ice sheet mass balance, namely sea-ice thickness and ice sheet elevations. In addition of polar regions coverage, around the globe data about cloud propriety information, vegetation canopy structure and topographic data were also recorded. It has proven to be a very successful mission, operating beyond its initial 5-year goal and saw its data applied effectively in many scientific models outside its initial application scope. The ICESat-2 satellite, the follow-up of the ICESat mission, with a more capable light detection and ranging (LIDAR) instrument, was launched in 2018 and represented an advancement over the laser technology of the first ICESat mission, firing laser pulses at 10 kHz rate, instead of the previous 40 Hz. This fast-firing laser technology allows the ICESat-2’s LIDAR, called Advanced Topographic Laser Altimeter System (ATLAS), to take measurements approximately at every 0.7 meters along the satellite’s track on Earth’s surface instead the 170 meters of the previous ICESat mission. Also, each transmitted laser pulse is split in six individual beams, arranged in three pairs (each pair having a strong and a weak beam) and separated by 3 km apart, providing a multi-beam profiling of the surface. The main objective of this thesis was the development of a software tool, called ICEComb, that allows scientists and researchers to visualise and process, in a suitable way, the available altimetry data from the ICESat mission and the ICESat-2 satellite, a follow-up of the previous mission, which was launched on the 15th of September 2018 and is currently operational. ICEComb is a web-based software tool that offers its users the ability to access the available data from both missions, visualise them interactively on a geographic map, store the data products locally, explore data in a detailed, efficient and meaningful way, and provide satellite altimetry data processing by implementing different algorithms and statistical procedures, thus providing an easy-to-use environment for analysis, interpretation and processing of satellite laser altimetry data. The need to create a new tool for processing and visualising the ICESat and ICESat-2 data products was derived primarily from the fact that existing solutions only provide access to a limited amount of information contained in the datasets of both missions and do not allow its processing and analysis in the same interface. The developed tool was built using well-known and well-documented technologies in order to facilitate the incorporation of new functionalities and features to it and allow to extend its application to data obtained from other satellite altimetry missions.
O primeiro sat´elite de altimetria a laser global da NASA, designado de ICESat (Ice, Cloud, and land Elevation Satellite), foi operado entre 2003 e 2009 com o objetivo principal da miss˜ao em medir as varia¸c˜oes de massa do manto de gelo da Terra, ou seja, as mudan¸ca de eleva¸c˜ao do manto de gelo e espessura do gelo marinho. Al´em da cobertura das regi˜oes polares, foram recolhidos dados `a volta do globo sobre propriedades das nuvens, estrutura da cobertura da vegeta¸c˜ao e dados topogr´aficos. Provou ser uma miss˜ao de muito sucesso, operando para al´em da sua meta inicial de cinco anos e viu os seus dados aplicados de forma eficaz em muitos modelos cient´ıficos fora do seu escopo inicial. O sat´elite ICESat-2, lan¸cado em 2018 no seguimento da miss˜ao ICESat, cont´em um instrumento LIDAR (LIght Detection And Ranging) mais capaz e representou um avan¸co da tecnologia laser da primeira miss˜ao ICESat, passando a disparar impulsos laser a uma taxa de 10 kHz em vez dos anteriores 40 Hz. Esta tecnologia laser de disparo r´apido permite que o sistema ATLAS (Advanced Topographic Laser Altimeter System) fa¸ca medi¸c˜oes aproximadamente a cada 0,7 metros ao longo da trilha do sat´elite sobre a superf´ıcie da Terra, em vez dos anteriores 170 metros da miss˜ao ICESat. Al´em disso, cada impulso laser transmitido ´e dividido em seis feixes individuais, dispostos em trˆes pares (compostos por um feixe forte e um feixe fraco) e separados por 3 km de distˆancia, fornecendo um perfil de feixe m´ultiplo da superf´ıcie. O principal objetivo deste trabalho foi o desenvolvimento de uma ferramenta de software, denominada ICEComb, que permite aos cientistas e investigadores processar e visualizar, de forma adequada, os dados dispon´ıveis de altimetria laser por sat´elite, nomeadamente dados da miss˜ao ICESat e do sat´elite ICESat-2, a miss˜ao que a sucedeu, lan¸cado a 15 de setembro de 2018 e que se encontra ainda em opera¸c˜ao. ICEComb ´e uma ferramenta baseada na web que oferece aos utilizadores finais uma aplica¸c˜ao para an´alise e interpreta¸c˜ao de dados de altimetria a laser por sat´elite com a capacidade de aceder aos dados dispon´ıveis de ambas as miss˜oes, visualiz´a-los interativamente num mapa geogr´afico, armazenar os registros de dados localmente, explorar os dados de forma eficiente, detalhada e significativa e realizar o processamento de dados de altimetria de sat´elite atrav´es dos diferentes algoritmos e procedimentos estat´ısticos implementados, proporcionando assim um ambiente de software de f´acil utiliza¸c˜ao. A necessidade da cria¸c˜ao de uma nova ferramenta para o processamento e a visualiza¸c˜ao dos produtos de dados dos sat´elites ICESat e ICESat-2 foi derivada principalmente do facto de que as solu¸c˜oes existentes apenas fornecem acesso a uma quantidade limitada de informa¸c˜ao contida nos conjuntos de dados de ambas as miss˜oes, al´em de n˜ao permitirem o seu processamento e an´alise na mesma interface. A ferramenta desenvolvida foi constru´ıda com tecnologias bem conhecidas e bem documentadas, de forma a facilitar a incorpora¸c˜ao de novas funcionalidades e fontes de dados, permitindo assim estender a sua aplicabilidade a dados de outras missões de altimetria laser por satélite.

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Hutcheson, Scott Edward. "Design and integration of a display for a low cost laser altimeter for general aviation applications." 2002. http://etd.utk.edu/2002/HutchesonScott.pdf.

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Thesis (MS)--University of Tennessee, Knoxville, 2002.
Title from title page screen (viewed on Sept. 27, 2002). Thesis advisor: William D. Lewis. Document formatted into pages (xii, 84 p. : ill.(some col.)). Vita. Includes bibliographical references (p. 75-77).

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Felikson, Denis. "Elevation and volume change of the ice sheets from GLAS : a comparison of methods." Thesis, 2013. http://hdl.handle.net/2152/24087.

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This report compares surface elevation change and volume change esti- mates from three methods: repeat track (RT), crossover (CX), and overlapping footprints (OFP). These three methods use different approaches to group- ing elevation point measurements taken at different measurement epochs and estimating elevation change. Volume changes are calculated from elevation changes in the same manner for all three methods but differences in sampling resolution between the methods affect volume change estimates in different ways. The recently reprocessed Release 633 version of elevation measurements from the Geoscience Laser Altimeter System (GLAS), flown on the Ice, Cloud and land Elevation Satellite (ICESat), are used in this analysis. Both elevation changes and volume changes are compared for both the Greenland Ice Sheet (GrIS) and the Antarctic Ice Sheet (AIS). Additionally, uncertainties in the estimates for each method are quantified and compared. Results are separated by drainage systems and by above/below 2000 m surface elevation for the GrIS. For the AIS, results are aggregated to the East, West, and Penin- vi sula regions. Volume change estimates agree well for the three methods for the GrIS, with estimates of -227.75 ± 2.12 km³/yr, -249.30 ± 3.42 km³/yr, and -218.24 ± 7.39 km³/yr for the RT, CX, and OFP methods, respectively. These estimates are similar to those published from previous studies. For the AIS, however, larger discrepancies are found in the estimates. This stems primarily from a large discrepancy in the volume change estimate of the East AIS, where the RT, CX, and OFP methods estimate volume changes of 33.39 ± 1.42 km³/yr, 46.42 ± 5.46 km³/yr, and -2.72 ± 2.12 km³/yr, respectively. It's not entirely clear why this large discrepancy exists in this particular region, and elevation change estimates for a few particular drainage systems in this region are examined. Previously published volume changes for the AIS also show a large scatter and more work must be done to reconcile the various estimates. Finally, the volume change uncertainties reported do not completely account for the discrepancies in most regions. Additional analysis must be done to completely quantify all error sources.
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Ivanov, Anton Borisovich. "Some aspects of the Martian climate in the Mars Orbiter Laser Altimeter (MOLA) investigation. Part I. Evolution of the polar residual ice caps. Part II. Polar night clouds. Part III. Interpretation of the MOLA reflectivity measurement in terms of the surface albedo and atmospheric opacity." Thesis, 2000. https://thesis.library.caltech.edu/7459/1/Ivanov%202000.pdf.

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The spacecraft exploration of the planet Mars in the last two decades provided scientists with an enormously rich data base. This work presents some aspects of the Mars Orbiter Laser Altimeter investigation related to the issues in the Martian climatology. The instrument continues to function on board of the Mars Global Surveyor Spacecraft.

The polar ice caps on Mars are the largest reservoirs of water on the planet. Their formation and evolution are not understood very well at this point. Ice flow, sublimation and wind erosion are believed to be the most important processes that shape the caps. We have developed a model to understand the role of sublimation for the formation of the ice caps and attempted to constrain the time scale for the formation of the observed ice caps. The model has been justified using the precise topography of the ice caps and the layered terrains that have been measured by the MOLA instrument. We argue that sublimation is a very important process for the formation of the caps, especially on the time scales greater than 10 million years.

We report the direct observations of CO_2 clouds, forming during the polar winter times over both poles. These clouds are similar over both poles and possibly represent a CO_2 snowfall. On the basis of the reflective properties and spatial occurrence, we can distinguish two major classes of clouds. We will discuss some hypotheses on the mechanisms of their formation.

Total atmospheric opacity of the Martian atmosphere at 1µm can be derived from the MOLA reflectivity measurement. Opacity estimates for the period from L_S = 105° to L_S = 220° are found to be consistent with the Viking Lander and Pathfinder values. Opacity measured in the polar regions displays storms and polar hood activity. Aerosol scale heights can be inferred from the opacity changes on some large scale topographic features. Dust scale heights are found to be lower than the atmospheric scale height. Water ice cloud scale heights are found to be consistent with the atmospheric scale height. Comparison of the MOLA derived opacity with the TES derived opacity yields information on the aerosol particle size distribution. We discuss an algorithm to derive 1µm normal albedo of the surface. 9µm dust opacity from the Thermal Emission Spectrometer (TES) is employed to remove an atmospheric attenuation from the MOLA reflectivity measurements. We will present some initial results on the calculation of the surface albedo.

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