scholarly journals A low-cost autonomous rover for polar science

2019 ◽  
Author(s):  
Andrew O. Hoffman ◽  
Hans Christian Steen-Larsen ◽  
Knut Christianson ◽  
Christine Hvidberg
Keyword(s):  
Modular Design ◽  
Low Cost ◽  
Digital Elevation Models ◽  
Ice Core ◽  
Snow Accumulation ◽  
Spatiotemporal Variability ◽  
Dual Frequency ◽  
Ice Stream ◽  
Digital Elevation ◽  
Software Instrumentation

Abstract. We present the developmental considerations, design, and deployment of an autonomous modular terrestrial rover for ice-sheet exploration that is inexpensive, easy to construct, and allows for instrumentation customization. Total construction cost for this rover is less than $3000, approximately one tenth the cost of existing platforms, and it can be built using facilities frequently available at academic institutions (machine shop, 3D printer, open-source hardware and software). Instrumentation deployed on this rover can be customized; the rover presented in this study was equipped with a dual-frequency GPS receiver and a digital SLR camera for constructing digital elevation models using structure-from motion (SfM) photogrammetry. We deployed this prototype rover on the Northeast Greenland Ice Stream to map local variations in snow accumulation and surface topography. The rover conducted four autonomous missions based out of the East Greenland Ice Core Project (EGRIP) camp during July 2017, measuring surface elevation transects across the hazardous ice-stream shear margins. During these missions, the rover proved capable of driving over 20 km on a single charge with a drawbar pull of 25°N, sufficient to tow commercial ground-penetrating radars. The rover also acquired photographs that were subsequently used to construct digital elevation models of a site monitored for spatiotemporal variability in snow accumulation, demonstrating adequate stability for high-resolution imaging applications. Due to its low cost, low-power requirements, and simple modular design, mass deployments of this rover design are practicable. Furthermore, operation of the rover in hazardous areas circumvents substantial expense and risk to personnel associated with conventional, crewed deployments. Thus, this rover is an investigatory platform that enables direct exploration of polar environments considered too hazardous for conventional field expeditions.

scholarly journals A low-cost autonomous rover for polar science

2019 ◽  
Vol 8 (1) ◽  
pp. 149-159 ◽  
Author(s):  
Andrew O. Hoffman ◽  
Hans Christian Steen-Larsen ◽  
Knut Christianson ◽  
Christine Hvidberg
Keyword(s):  
Modular Design ◽  
Low Cost ◽  
Digital Elevation Models ◽  
Ice Core ◽  
Snow Accumulation ◽  
Spatiotemporal Variability ◽  
Dual Frequency ◽  
Ice Stream ◽  
Digital Elevation ◽  
Software Instrumentation

Abstract. We present the developmental considerations, design, and deployment of an autonomous modular terrestrial rover for ice-sheet exploration that is inexpensive, easy to construct, and allows for instrumentation customization. The total construction cost for this rover is less than USD 3000, approximately one-tenth the cost of existing platforms, and it can be built using facilities frequently available at academic institutions (machine shop, 3-D printer, open-source hardware and software). Instrumentation deployed on this rover can be customized; the rover presented in this study was equipped with a dual-frequency GPS receiver and a digital SLR camera for constructing digital elevation models using structure-from-motion (SfM) photogrammetry. We deployed this prototype rover on the Northeast Greenland Ice Stream to map local variations in snow accumulation and surface topography. The rover conducted four autonomous missions based out of the East Greenland Ice-Core Project (EastGRIP) camp during July 2017, measuring surface elevation transects across the hazardous ice-stream shear margins. During these missions, the rover proved capable of driving over 20 km on a single charge with a drawbar pull of 250 N, sufficient to tow instrumentation of up to 100 kg. The rover also acquired photographs that were subsequently used to construct digital elevation models of a site monitored for spatiotemporal variability in snow accumulation, demonstrating adequate stability for high-resolution imaging applications. Due to its low cost, low-power requirements, and simple modular design, mass deployments of this rover design are practicable. Operation of the rover in hazardous areas circumvents the substantial expense and risk to personnel associated with conventional, crewed deployments. Thus, this rover is an investigatory platform that enables direct exploration of polar environments considered too hazardous for conventional field expeditions.

scholarly journals Construction of Digital Elevation Models for a Southern European City and a Comparative Morphological Analysis with Respect to Northern European and North American Cities

2010 ◽  
Vol 49 (7) ◽  
pp. 1377-1396 ◽  
Author(s):  
Silvana Di Sabatino ◽  
Laura S. Leo ◽  
Rosella Cataldo ◽  
Carlo Ratti ◽  
Rex E. Britter
Keyword(s):  
North American ◽  
Low Cost ◽  
Digital Elevation Models ◽  
Urban Canopy ◽  
European City ◽  
Dispersion Models ◽  
Northern European ◽  
Digital Elevation ◽  
Urban Flow ◽  
American Cities

Abstract A morphometric analysis of a southern European city and the derivation of relevant fluid dynamical parameters for use in urban flow and dispersion models are explained in this paper. Calculated parameters are compared with building statistics that have already been computed for parts of three northern European and two North American cities. The aim of this comparison is to identify similarities and differences between several building configurations and city types, such as building packing density, compact versus sprawling neighborhoods, regular versus irregular street orientation, etc. A novel aspect of this work is the derivation and use of digital elevation models (DEMs) for parts of a southern European city. Another novel aspect is the DEMs’ construction methodology, which is low cost, low tech, and of simple implementation. Several building morphological parameters are calculated from the urban DEMs using image processing techniques. The correctness and robustness of these techniques have been verified through a series of sensitivity tests performed on both idealized building configurations, as well as on real case DEMs, which were derived using the methodology here. In addition, the planar and frontal area indices were calculated as a function of elevation. It is argued that those indices, estimated for neighborhoods of real cities, may be used instead of the detailed building geometry within urban canopy models as those indices together synthesize the geometric features of a city. The direct application of these results will facilitate the development of fast urban flow and dispersion models.

scholarly journals A method based on structure-from-motion photogrammetry to generate sub-millimetre-resolution digital elevation models for investigating rock breakdown features

2019 ◽  
Vol 7 (1) ◽  
pp. 45-66 ◽  
Author(s):  
Ankit Kumar Verma ◽  
Mary Carol Bourke
Keyword(s):  
High Resolution ◽  
Structure From Motion ◽  
Low Cost ◽  
Digital Elevation Models ◽  
Point Clouds ◽  
Experimental Conditions ◽  
Weathered Rock ◽  
Topographic Data ◽  
Digital Elevation ◽  
Dense Point

Abstract. We have generated sub-millimetre-resolution DEMs of weathered rock surfaces using SfM photogrammetry techniques. We apply a close-range method based on structure-from-motion (SfM) photogrammetry in the field and use it to generate high-resolution topographic data for weathered boulders and bedrock. The method was pilot tested on extensively weathered Triassic Moenkopi sandstone outcrops near Meteor Crater in Arizona. Images were taken in the field using a consumer-grade DSLR camera and were processed in commercially available software to build dense point clouds. The point clouds were registered to a local 3-D coordinate system (x, y, z), which was developed using a specially designed triangle-coded control target and then exported as digital elevation models (DEMs). The accuracy of the DEMs was validated under controlled experimental conditions. A number of checkpoints were used to calculate errors. We also evaluated the effects of image and camera parameters on the accuracy of our DEMs. We report a horizontal error of 0.5 mm and vertical error of 0.3 mm in our experiments. Our approach provides a low-cost method for obtaining very high-resolution topographic data on weathered rock surfaces (area < 10 m2). The results from our case study confirm the efficacy of the method at this scale and show that the data acquisition equipment is sufficiently robust and portable. This is particularly important for field conditions in remote locations or steep terrain where portable and efficient methods are required.

scholarly journals Creating Low-Cost High-Resolution Digital Elevation Models

2003 ◽  
Vol 56 (1) ◽  
pp. 92 ◽  
Author(s):  
M. Louhaichi ◽  
M. M. Borman ◽  
A. L. Johnson ◽  
D. E. Johnson
Keyword(s):  
High Resolution ◽  
Low Cost ◽  
Digital Elevation Models ◽  
Digital Elevation

scholarly journals Is GNSS real-time positioning a reliable option to validate erosion studies at olive grove environments?

2020 ◽  
Vol 18 (2) ◽  
pp. e0204
Author(s):  
María S. Garrido-Carretero ◽  
María I. Ramos-Galán ◽  
María C. De Lacy-Pérez de los Cobos ◽  
Sergio Blanca-Mena ◽  
Antonio J. Gil-Cruz
Keyword(s):  
Low Cost ◽  
Satellite System ◽  
Single Frequency ◽  
Olive Grove ◽  
Dual Frequency ◽  
Significance Level ◽  
Digital Elevation ◽  
Significant Difference ◽  
Spatial Redistribution ◽  
Global Navigation Satellite

Aim of study: Soil degradation in agricultural areas is a widespread problem. In this framework, a data validation methodology is presented, including a study of the spatial resolution of Global Navigation Satellite System (GNSS) measurements, the calculation of erosion/deposition models, and the contribution of dual frequency and low-cost single frequency GNSS receivers.Area of study: A test olive grove in SE Spain.Material and methods: The study is based on three observation campaigns, between 2016 and 2018, using different GNSS receivers and working modes. The comparison between different surveys provide the volumetric variation over the analyzed period.Main results: Considering the dual-frequency receiver, there was no statistically significant difference between the means and the variances from 1.5 m and from 4.5 m data resolution at the 0.05 significance level. In order to estimate vertical differences from successive GNSS campaigns a differential digital elevation approach was applied. Although the differences depended on the zone of the test area and they changed along the monitoring period, the erosion rate could be catalogued as very low. The dual-frequency receiver satisfied the vertical centimetric precision limits for high accurate Digital Elevation Model (DEM), making it a reliable and accurate option to validate erosion studies in small areas.Research highlights: The results have allowed the characterization of multi-annual spatial redistribution of the topsoil at local scale, being of great help to design future prevention actions for the “tillage erosion” in olive grove environments. However, more tests are needed to guarantee the feasibility of low-cost receivers.

scholarly journals Creating low-cost high-resolution digital elevation models.

2006 ◽  
Vol 56 (1) ◽  
Author(s):  
M. Louhaichi ◽  
M.M. Borman ◽  
A.L. Johnson ◽  
D.E. Johnson
Keyword(s):  
High Resolution ◽  
Low Cost ◽  
Digital Elevation Models ◽  
Digital Elevation

scholarly journals Surface velocity of the Northeast Greenland Ice Stream (NEGIS): assessment of interior velocities derived from satellite data by GPS

2020 ◽  
Vol 14 (10) ◽  
pp. 3487-3502 ◽  
Author(s):  
Christine S. Hvidberg ◽  
Aslak Grinsted ◽  
Dorthe Dahl-Jensen ◽  
Shfaqat Abbas Khan ◽  
Anders Kusk ◽  
...  
Keyword(s):  
Ice Core ◽  
Surface Velocity ◽  
The Arctic ◽  
Transverse Strain ◽  
Ice Stream ◽  
Digital Elevation ◽  
Ice Flows ◽  
Order Of Magnitude ◽  
Drilling Site ◽  
Elevation Model

Abstract. The Northeast Greenland Ice Stream (NEGIS) extends around 600 km upstream from the coast to its onset near the ice divide in interior Greenland. Several maps of surface velocity and topography of interior Greenland exist, but their accuracy is not well constrained by in situ observations. Here we present the results from a GPS mapping of surface velocity in an area located approximately 150 km from the ice divide near the East Greenland Ice-core Project (EastGRIP) deep-drilling site. A GPS strain net consisting of 63 poles was established and observed over the years 2015–2019. The strain net covers an area of 35 km by 40 km, including both shear margins. The ice flows with a uniform surface speed of approximately 55 m a−1 within a central flow band with longitudinal and transverse strain rates on the order of 10−4 a−1 and increasing by an order of magnitude in the shear margins. We compare the GPS results to the Arctic Digital Elevation Model and a list of satellite-derived surface velocity products in order to evaluate these products. For each velocity product, we determine the bias in and precision of the velocity compared to the GPS observations, as well as the smoothing of the velocity products needed to obtain optimal precision. The best products have a bias and a precision of ∼0.5 m a−1. We combine the GPS results with satellite-derived products and show that organized patterns in flow and topography emerge in NEGIS when the surface velocity exceeds approximately 55 m a−1 and are related to bedrock topography.

scholarly journals Photogrammetric Measurement of Erosion at the Sabbath Point Beothuk Site in Central Newfoundland, Canada

2020 ◽  
Vol 12 (18) ◽  
pp. 7555
Author(s):  
James Williamson ◽  
Ionut Cristi Nicu
Keyword(s):  
Low Cost ◽  
Digital Elevation Models ◽  
Archaeological Site ◽  
River Valley ◽  
Archaeological Sites ◽  
Archaeological Research ◽  
Grass Gis ◽  
Digital Elevation ◽  
Photogrammetric Measurement

Erosion at archaeological sites in Central Newfoundland, Canada is a major concern, which is compounded by the fact that there has been a dearth of archaeological research in this region. While more than 70 house pits are known, very few excavations have examined whole features in the Exploits River Valley (ERV), and the archaeology of many has not been examined yet. The aim of this study is to examine the rate of erosion at the Sabbath Point house pit, a recently recorded archaeological site, located on the bank of Red Indian Lake (RIL), and to describe a low-cost methodology for analysing site level bank changes. This site is particularly important, as it represents an example of a late Beothuk residential feature about lifeways practiced in this region. The surveys employed here were carried out using image-based modelling. GRASS GIS was used to measure the diachronic difference between bank edges. The Digital Elevation Models (DEMs) were then compared, and the differences were measured using a transect based method. The erosion measurement has shown that Sabbath Point is in danger of being completely eroded. This shows that a salvage excavation program covering the entire feature is necessary within the next few years, as the feature itself will begin to erode.

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