Development of an acoustic positioning system for the minimally invasive exploration of a sub glacial water reservoir at the Taylor Glacier within the Enceladus Explorer (EnEx) project : Entwicklung des akustischen Lokalisierungssystems der Enceladus-Explorer-Einschmelzsonde für die minimal-invasive Entnahme einer subglazialen Flüssigkeitsprobe am antarktischen Taylor-Gletscher

• Main Author: Heinen, Dirk
• Format: Thesis
• Language: German
• Published: RWTH Aachen University 2018
• Subjects: Lokalisierung , Akustische Navigation , Schmelzsond , Enceladus , EnEx , Gletscher; Jupiter; Taylor Glacier; Blood Falls; Taylor-Gletscher; Saturn; Antarc*; Antarctica; Antarktis*
• Online Access: https://dx.doi.org/10.18154/rwth-2018-229179; http://publications.rwth-aachen.de/record/748132

Dissertation, RWTH Aachen University, 2018; Aachen 1 Online-Ressource (v, 147 Seiten) : Illustrationen, Diagramme (2018). = Dissertation, RWTH Aachen University, 2018 : Finding extraterrestrial life or proving its existence are enormous challenges. Candidate places to find this life are already found within the solar system. Of particular interest are the icy moons of Saturn and Jupiter, which contain a liquid ocean inside. One of these ice moons is Saturn’s moon Enceladus. Life could exist in its ocean, protected by a kilometer-thick ice shell. The ice shell would need to be penetrated to reach the liquid ocean inside. This could be achieved by a melting probe that autonomously navigates to the ocean. The knowledge of its current position is essential for the autonomous navigation of the EnEx probe. Within the framework of the Enceladus Explorer Initiative (EnEx) of the DLR Space Administration, the necessary navigation technologies and navigation systems for such a probe, named the EnEx probe, are being developed. Various systems based on different navigation methods are integrated into the EnEx probe and demonstrated in suitable terrestrial environments. The data of all navigation systems are fused to determine the current position and orientation with an optimal accuracy. Within this work, an acoustic positioning system, the APS, was designed and built. The main objectives of this thesis were the concept of the overall system and the development and integration of the APS sensors and to test the APS in glacier ice. The APS uses six acoustic emitters on the glacier surface. Four acoustic sensors are located in the melting probe. The data acquisition is started synchronously with the signal generation. The signal processing extracts the propagation times from the recorded acoustic signals. The current position of the probe can be reconstructed by trilateration, based on the signal propagation times, the positions of the emitters and the speed of sound of the ice. The APS was validated in several test campaigns in water and glacier ice. These test campaigns enabled further developments of the system. Finally, the APS was used as one of the navigation systems of the EnEx probe at the Blood Falls at the Taylor Glacier in Antarctica. In this demonstration the EnEx probe encountered a fluid-filled subglacial reservoir and minimally invasively retrieved a fluid sample. : Published by Aachen