Evaluation of a Novel Uav-Borne Topo-Bathymetric Laser Profiler

Mandlburger, Gottfried; Pfennigbauer, Martin; Wieser, Martin; Riegl, Ursula; Pfeifer, Norbert

doi:10.5194/isprs-archives-xli-b1-933-2016

Cited by 20 publications

(11 citation statements)

References 12 publications

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“…An exception is the novel topo-bathymetric laser profiler, bathymetric depth finder BDF-1 (Mandlburger et al, 2016). This lidar profiler can retrieve measurements of up to 1-1.5 times the Secchi depth; thus, it is only suitable for shallow gravelbed water bodies.…”

Section: F Bandini Et Al: Bathymetry Observations Of Inland Water Bmentioning

confidence: 99%

Technical note: Bathymetry observations of inland water bodies using a tethered single-beam sonar controlled by an unmanned aerial vehicle

Bandini

Olesen

Jakobsen

et al. 2018

Hydrol. Earth Syst. Sci.

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Abstract. High-quality bathymetric maps of inland water bodies are a common requirement for hydraulic engineering and hydrological science applications. Remote sensing methods, such as space-borne and airborne multispectral imaging or lidar, have been developed to estimate water depth, but are ineffective for most inland water bodies, because of the attenuation of electromagnetic radiation in water, especially under turbid conditions. Surveys conducted with boats equipped with sonars can retrieve accurate water depths, but are expensive, time-consuming, and unsuitable for unnavigable water bodies.We develop and assess a novel approach to retrieve accurate and high-resolution bathymetry maps. We measured accurate water depths using a tethered floating sonar controlled by an unmanned aerial vehicle (UAV) in a lake and in two different rivers located in Denmark. The developed technique combines the advantages of remote sensing with the potential of bathymetric sonars. UAV surveys can be conducted also in unnavigable, inaccessible, or remote water bodies. The tethered sonar can measure bathymetry with an accuracy of ∼ 2.1 % of the actual depth for observations up to 35 m, without being significantly affected by water turbidity, bed form, or bed material.

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Section: F Bandini Et Al: Bathymetry Observations Of Inland Water Bmentioning

confidence: 99%

Technical note: Bathymetry observations of inland water bodies using a tethered single-beam sonar controlled by an unmanned aerial vehicle

Bandini

Olesen

Jakobsen

et al. 2018

Hydrol. Earth Syst. Sci.

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“…However, these passive methods are limited to very shallow and clear water. Innovative UAS‐borne LIDAR systems (Kinzel & Legleiter, 2019; Mandlburger et al., 2016) can be deployed with UAS, but these systems are highly expensive and can penetrate only to 1–1.2 times the Secchi depth. Bandini et al.…”

Section: Discussionmentioning

confidence: 99%

“…However, these passive methods are limited to very shallow and clear water. Innovative UAS-borne LIDAR systems (Kinzel & Legleiter, 2019;Mandlburger et al, 2016) can be deployed with UAS, but these systems are highly expensive and can penetrate only to 1-1.2 times the Secchi depth. Bandini et al (2018) show the possibility to use a UAS-tethered sonar to retrieve bathymetry in lakes and streams, but the solution is still not fully autonomous, as it requires an operator near the UAS platform to ensure flight safety.…”

Section: Uas-borne Bathymetry Measurements and Seeding For A Fully Contactless Methodsmentioning

confidence: 99%

A Drone‐Borne Method to Jointly Estimate Discharge and Manning's Roughness of Natural Streams

Bandini

Lüthi²,

Peña‐Haro³

et al. 2021

Water Resources Research

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Image cross‐correlation techniques, such as particle image velocimetry (PIV), can estimate water surface velocity (v surf) of streams. However, discharge estimation requires water depth and the depth‐averaged vertical velocity (U m ). The variability of the ratio U m /v surf introduces large errors in discharge estimates. We demonstrate a method to estimate v surf from Unmanned Aerial Systems (UASs) with PIV technique. This method does not require any ground control point (GCP): the conversion of velocities from pixels per frame into length per time is performed by informing a camera pinhole model; the range from the pinhole to the water surface is measured by the drone‐borne radar. For approximately uniform flow, U m is a function of the Gauckler‐Manning‐Strickler coefficient (K s ) and v surf. We implement an approach that can be used to jointly estimate K s and discharge by informing a system of two unknowns (K s and discharge) and two nonlinear equations: i) Manning's equation and ii) mean‐section method for computing discharge from U m . This approach relies on bathymetry, acquired in situ a priori, and on UAS‐borne v surf and water surface slope measurements. Our joint (discharge and K s ) estimation approach is an alternative to the widely used approach that relies on estimating U m as 0.85·v surf. It was extensively investigated in 27 case studies, in different streams with different hydraulic conditions. Discharge estimated with the joint estimation approach showed a mean absolute error of 19.1% compared to in situ discharge measurements. K s estimates showed a mean absolute error of 3 m1/3/s compared to in situ measurements.

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“…Seamless acquisition of elevation data along a topographic-bathymetric gradient for this purpose is possible through the application of a green, short-pulse laser range finder operating on a UAV (e.g. Mandlburger et al, 2016).…”

Section: Boulder Mapping From Orthophotographs and The Digital Surfacmentioning

confidence: 99%

Digital mapping of coastal boulders – high‐resolution data acquisition to infer past and recent transport dynamics

et al. 2019

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Coastal boulder fields provide clues to long‐term frequency‐magnitude patterns of coastal flooding events and have the potential to play an important role in coastal hazard assessment. Mapping boulders in the field is time and labour‐intensive, and work on intertidal reef platforms, as in the present study, is physically challenging. By addressing coastal scientists who are not specialists in remote sensing, this contribution reports on the possibilities and limitations of digital applications in boulder mapping in Eastern Samar, Philippines, where recent supertyphoons Haiyan and Hagupit induced high waves, coastal flooding and boulder transport. It is demonstrated how satellite imagery of sub‐metre resolution (from Pléiades and WorldView‐3 imagery) enables efficient analysis of transport vectors and distances of larger boulders, reflecting variation in latitudes of both typhoon tracks and approaching angles of typhoon‐generated waves. During the investigated events, boulders with a‐axes of up to 8 m were clearly identified to have been shifted for up to 32 m, mostly along the seaward margin of the boulder field. It is, however, hard to keep track of smaller boulders, and the length of a‐axes and b‐axes including their orientation is often impossible to map with sufficient accuracy. Orthophotographs and digital surface models created through the application of an unmanned aerial vehicle and the ‘Structure from Motion’ technique provide ultra‐high‐resolution data, and have the potential to not only improve the results of satellite image analysis, but also those from field mapping and may significantly reduce overall time in the field. Orthophotographs permit unequivocal mapping of a‐axes and b‐axes including their orientation, while precise values for c‐axes can be derived from the respective digital surface models. Volume of boulders is best inferred from boulder‐specific Structure from Motion‐based three‐dimensional models. Battery power, flight speed and altitude determine the limits of the area covered, while patches shielded by the boulders are difficult to resolve. For some tasks, field mapping remains mandatory and cannot be replaced by currently available remote sensing tools: for example, sampling for rock type, density and age dating, recording of lithological separation of boulders from the underlying geological unit and of geomorphic features on a millimetre to decimetre‐scale, or documentation of fine‐grained sediment transport in between the boulders in supratidal settings. In terms of future events, the digital products presented here will provide a valuable reference to track boulder transport on a centimetre to decimetre‐scale and to better understand the hydrodynamics of extreme‐wave events on a fringing reef coastline.

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Evaluation of a Novel Uav-Borne Topo-Bathymetric Laser Profiler

Cited by 20 publications

References 12 publications

Technical note: Bathymetry observations of inland water bodies using a tethered single-beam sonar controlled by an unmanned aerial vehicle

Technical note: Bathymetry observations of inland water bodies using a tethered single-beam sonar controlled by an unmanned aerial vehicle

A Drone‐Borne Method to Jointly Estimate Discharge and Manning's Roughness of Natural Streams

Digital mapping of coastal boulders – high‐resolution data acquisition to infer past and recent transport dynamics

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