50 research outputs found

    Quad-Polarimetric SAR for Detection and Characterization of Icebergs

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    Website for ESA Living Planet Symposium 2016.This paper evaluates the performance of fully polarimetric SAR data in iceberg detection and characterization. The study aims to explore the potential of RADARSAT-2 SAR data to detect icebergs and growlers in Svalbard that have broken off from the glaciers nearby. To be able to detect iceberg/growlers in a SAR image, a significant contrast between iceberg and background clutter is required. The sublook cross-correlation magnitude (SCM) is extracted from the complex cross-correlation between subapeture images and contrast between iceberg and sea clutter is measured. The results of target-to-clutter ratio from the SCM indicate that the sublook analysis has an impact on detection performance

    UAV-BORNE UWB RADAR FOR SNOWPACK SURVEYS

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    Source at https://hdl.handle.net/11250/2649630In this report we summarize the capabilities and technical characteristics of our UAV-borne UWB radar system, designed for conducting snow surveys. We developed an ultrawideband snow sounder that is capable of imaging snow stratigraphy with a 5 cm range resolution. The radar can be carried by an octocopter UAV in order to carry out airborne snowpack surveys. During a demonstration on Andøya, we showed that the radar was capable of resolving snow stratigraphy in wet snow conditions, as well as detecting a buried person under 1.5 m of wet snow. In this report, we present the results of the demonstration in detail. We furthermore discuss capabilities and incapabilities of our radar system and offer a list of future steps to bring it to an operational status

    From glacier facies to SAR Backscatter Zones via GPR

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    Testing UAVs to perform aerial photographic survey of harp and hooded seals in the West Ice area

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    Survey report – KV “Svalbard” 16-26 March 2014The aim of the KV “Svalbard” survey was to test two UAVs (Unmanned Aerial Vehicles) to perform aerial photographic surveys of harp and hooded seal whelping patches on the drift ice in the West Ice area in the Greenland Sea. Digital cameras and a thermal infrared (IR) camera were used. We aimed to explore various survey altitudes and camera settings to obtain an optimal altitude and camera set up for photographing seal pups. Simultaneous use of digital and IR cameras enable us to explore combinations of those to detect and classify seals. Experience obtained from using the UAVs and the quality of the images taken, are promising. Both harp and hooded seals, including pups, were easily identified on the images taken at a flight altitude of 300 m. Also preliminary results from the IR camera are promising. It is, however, necessary to improve the range of the largest UAV and the methods for landing the aircraft on ice floes. Also some technical improvements on both aircrafts and operational equipment should be performe

    Safety and security of drones in the oil and gas industry

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    This paper describes safety and security challenges and best practices of the use of drones in the oil and gas industry, with consideration of the harsh weather conditions in the Northern Territories of Norway. We have described the present status of the use of drones in air, on water (surface) and under water. Drones are being used in the industry to reduce or remove dangerous, dirty or dull operations from humans and to increase quality of data collection. The Norwegian oil and gas industry and authorities have a high focus on continuous improvement of safety, security and environmental issues. This has for instance resulted in the offshore helicopter transport in Norway to be among the safest offshore transport worldwide. Use of drones in the safety conscious oil and gas industry, should help us to improve the safety practices of drone use in general. Our suggestions are to focus on systematic data reporting of the use of drones, establish guidelines for risk assessments and operations, improve the use and testing of drones in the industry (i.e. build more experience) and support improved robustness and resilience of drone use. In addition, we see the need for improved quality of the interfaces between human operators and drones to ensure meaningful human control.publishedVersio

    Bruk av droner i nordomrĂĽdene

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    Formület med denne rapporten er ü vise eksempler pü bruk av fjernstyrte og autonome droner i petroleumssektoren og vise hvilke utviklingstrender innen droneteknologi som er viktige. Utfordringer og muligheter for bruk av droner i nordomrüdene er spesielt vektlagt. Teknologi for og anvendelser av flyvende droner, droner pü havoverflaten og droner under vann er behandlet i denne rapporten. Rapporten beskriver hvordan droner brukes i dag og oppgaver dronene kan løse fremover. Rapporten beskriver utfordringer ved bruk av droner innen petroleumsvirksomheten og forslag til tiltak

    A review of unmanned vehicles for the detection and monitoring of marine fauna

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    Recent technology developments have turned present-day unmanned systems into realistic alternatives to traditional marine animal survey methods. Benefits include longer survey durations, improved mission safety, mission repeatability, and reduced operational costs. We review the present status of unmanned vehicles suitable for marine animal monitoring conducted in relation to industrial offshore activities, highlighting which systems are suitable for three main monitoring types: population, mitigation, and focal animal monitoring. We describe the technical requirements for each of these monitoring types and discuss the operational aspects. The selection of a specific sensor/platform combination depends critically on the target species and its behaviour. The technical specifications of unmanned platforms and sensors also need to be selected based on the surrounding conditions of a particular offshore project, such as the area of interest, the survey requirements and operational constraints

    Experimental And Theoretical Investigation Of Stratospheric Ozone Depletion In The Northern Hemisphere Caused By Heterogeneous Chemistry

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    Thesis (Ph.D.) University of Alaska Fairbanks, 2001Stratospheric ozone is of crucial importance for life on Earth. This thin layer protects us from the ultraviolet solar radiation and also works as a greenhouse gas that helps maintaining our climate. Large changes in thickness and vertical distribution of the ozone abundance may have detrimental effects on life on Earth. But even small changes could have considerable impact on UV irradiance, bio-production and cancer rates. During the last decade record low spring time vertical column amounts of stratospheric ozone have been observed over Northern Europe. However, this decrease is not as severe as the depletion observed over Antarctica and at mid-latitudes in the Southern Hemisphere. The discovery of the spring time stratospheric ozone depletion first in Antarctica and later in the Arctic has triggered international research efforts on stratospheric ozone chemistry and the possible effects of human activities on the ozone layer. Ground-based differential optical absorption spectroscopy measurements of NO2 and ozone have been performed over Fairbanks (65�N) and Ny-Alesund (79�N) during the 1994--95 season. In this work we present improvements to ground based differential optical spectroscopy measurements by improving dark current corrections and spectral fitting of spectrographic photo diode array detector measurements. We have also improved the retrieval of vertical column amounts from diffuse light measurements by improving the corrections for seasonal changes in absorber air mass. This is particularly important at high latitudes. We used these data together with local weather and ozone sounding data, and with trace gas and aerosol data measured by other ground based instruments and by instruments deployed on satellites. This comprehensive dataset was used to investigate the performance of two current state of the art chemical transport models with and without the presence of heterogeneous chemistry. These are the University of Cambridge SLIMCAT model and the University of Oslo SCTM-1 model. They were selected because the SLIMCAT is designed for process studies and comparison with measured data while the SCTM-1 is designed for prognostic and sensitivity studies aimed at predicting future development of the stratospheric ozone layer. We have used the models to study the sensitivity of the heterogeneous chemistry to stratospheric meteorological conditions and the effect of sulfuric acid aerosols and polar stratospheric clouds on the stratospheric ozone abundance and ozone chemistry at high- and mid-latitudes in the Northern Hemisphere
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