Der Alpenraum und seine Herausforderungen im Bereich Orientierung, Navigation und Informationsaustausch

Nach zwijähriger Absenz ist AHORN heuer wieder nach Österreich, genauer gesacht nach Tirol, zurückgekehrt. Wie sich wohl so manches OVN-Mitglied erinnern wird, wurde diese Tagungsserie im April 2002 durch den OVN als Dreiländertagung zwischen Österreich, Deutschland und der Schweiz ins Leben gerufen. Nach den bisherigen Veranstaltungsorten Imst, Davos und Spitzingsee konnten in diesem Jahr dankenswerterweise die hervorragend geeigneten Räumlichkeiten des K-Plus Kompetenzzentrums alpS - Zentrum für Naturgefahren Management GmbH in Innsbruck zur Abhaltung der Tagung genützt werden

Real-time processing of GPS/INS data for on-the-fly quality control in airborne mobile mapping.

Scan2Map is an airborne remote-sensing system developed under the lead of the TOPO lab at the EPFL. Typically operated aboard a helicopter, it is dedicated for small mission areas (a few square kilometres at the maximum) and offers a sub-decimetre accuracy of the derived mapping products (orthophotos, digital surface- and terrain models). To achieve this high quality independently from ground control, Scan2Map relies on GPS/INS for determining the parameters of exterior orientation of the image sensors (i.e., a digital camera and a Lidar line scanner). In order to guarantee the complete coverage of a given area of interest, a detailed flight plan needs to be elaborated and it is essential to follow this plan as closely as possible during the flight. However, certain types of problems may remain hidden during the data recording, e.g., insufficient Lidar coverage due to poor ground reflectance. To avoid suchlike situations, an online monitoring tool is currently under development that allows assessing the quality of the recorded data while in the air. Among other calculations, this tool requires the real-time processing of the GPS/INS data. The paper describes the principles of airborne mobile mapping by Scan2Map, discusses cer-tain aspects of the real-time GPS/INS processing, and shows some initial results obtained during the development of the quality-assessment tool

Reliability of Direct Georeferencing Phase 2: A Case Study on Practical Problems and Solutions., Checking and Improving of Digital Terrain Models / Reliability of Direct Georeferencing.

This report studies a practical problem related to the use of GPS/INS technology for sensor direct georeferencing. It is a case study of a specific, yet typical, situation whre the performance of a GPS/INS was pronounced unsatisfactory for orientation of an airborne sensor. However, it was in fact not the poor quality of the navigation data but rather numerous disregards occurring in the flight execution and data treatment that have led to this wrong conclusion. The presented analysis reveals the errors committed at different stages of data treatment and quantifies their impact on the sensor exterior orientation. It also explains the remedies employed to mitigate their impact. The recommended procedures are drafted in a summary

Accuracy Estimation for Laser Point Cloud Including Scanning Geometry

Individual points produced by airborne laser scanning (ALS) may have large variation in their accuracy, a fact that is often omitted in the subsequent derivation of digital terrain models. The accuracy of a single point is governed by three main factors: First, the errors due to the direct georeferencing of the laser beam; second, the measurement errors of the laser itself; third, the variation of the range-finder error due to the changing scanning geometry. The influence of the first two sources can be estimated by means of error propagation via known functional relations of georeferencing. Nevertheless, the influence of the third component is much harder to assess as it requires a-priori knowledge of the local terrain normal to compute the incident angle and the laser footprint. We propose a novel approach that analyzes the scanning geometry quantitatively by estimating the local terrain normal directly from the laser point cloud. Adding this information to the error propagation yields a final quality indicator that reflects not only the georeferencing quality but also the scanning geometry. The paper presents first results of the developed algorithm and assesses the possibilities to use such q-indicators within DTM/DSM-production. Their benefits are especially investigated for automated data classification and generation of DTM quality metadata

Identification of polyhydroxyalkanoates in Halococcus and other haloarchaeal species

Polyhydroxyalkanoates (PHAs) are accumulated in many prokaryotes. Several members of the Halobacteriaceae produce poly-3-hydroxybutyrate (PHB), but it is not known if this is a general property of the family. We evaluated identification methods for PHAs with 20 haloarchaeal species, three of them isolates from Permian salt. Staining with Sudan Black B, Nile Blue A, or Nile Red was applied to screen for the presence of PHAs. Transmission electron microscopy and 1H-nuclear magnetic resonance spectroscopy were used for visualization of PHB granules and chemical confirmation of PHAs in cell extracts, respectively. We report for the first time the production of PHAs by Halococcus sp. (Halococcus morrhuae DSM 1307T, Halococcus saccharolyticus DSM 5350T, Halococcus salifodinae DSM 8989T, Halococcus dombrowskii DSM 14522T, Halococcus hamelinensis JCM 12892T, Halococcus qingdaonensis JCM 13587T), Halorubrum sp. (Hrr. coriense DSM 10284T, Halorubrum chaoviator DSM 19316T, Hrr. chaoviator strains NaxosII and AUS-1), haloalkaliphiles (Natronobacterium gregoryi NCMB 2189T, Natronococcus occultus DSM 3396T) and Halobacterium noricense DSM 9758T. No PHB was detected in Halobacterium salinarum NRC-1 ATCC 700922, Hbt. salinarum R1 and Haloferax volcanii DSM 3757T. Most species synthesized PHAs when growing in synthetic as well as in complex medium. The polyesters were generally composed of PHB and poly-ß-hydroxybutyrate-co-3-hydroxyvalerate (PHBV). Available genomic data suggest the absence of PHA synthesis in some haloarchaea and in all other Euryarchaeota and Crenarchaeota. Homologies between haloarchaeal and bacterial PHA synthesizing enzymes had indicated to some authors probable horizontal gene transfer, which, considering the data obtained in this study, may have occurred already before Permian times

Reliability of direct georeferencing: A case study on practical problems and solutions: Final Report on Phase 2

This report studies a practical problem related to the use of GPS/INS technology for sensor direct georeferencing. It is a case study of a specific, yet typical, situation where the performance of a GPS/INS was pronounced unsatisfactory for orientation of an airborne sensor. However, it was in fact not the poor quality of the navigation data but rather numerous disregards occurring in the flight execution and data treatment that have led to this wrong conclusion. The presented analysis reveals the errors committed at different stages of data treatment and quantifies their impact on the sensor exterior orientation. It also explains the remedies employed to mitigate their impact. The recommended procedures are drafted in a summary