Becker, David (2016)
Advanced Calibration Methods for Strapdown Airborne Gravimetry.
Technische Universität Darmstadt
Dissertation, Erstveröffentlichung
Kurzbeschreibung (Abstract)
Airborne gravimetry is the determination of the Earth's gravity field, using aircraft as mobile measurement platforms. For such measurements, there exist two predominant types of instrumentation: 1. Mechanical spring gravimeters, which are mounted on a gimballed platform in order to maintain a constant sensor orientation during the flight, aligned with the local vertical of the gravity field; 2. aircraft body-fixed 'strap-down' Inertial Measurement Units (IMU), containing each one sensor triad of accelerometers and gyroscopes. While IMUs are commonly designed for navigation applications, they also turn out to have several practical advantages also for gravimetric applications, compared to the more established platform-stabilised spring-gravimeters. In particular advantageous are the lower space and energy consumption, the autonomous operation during the flights, the lower sensitivity to turbulence, and the considerably lower acquisition costs.
This thesis is a contribution to the improvement of kinematic, IMU-based gravimetry (denoted as \emph{strapdown gravimetry}). In practice, the predominant source of errors of such systems arises from uncompensated accelerometer drifts. It is shown theoretically, and based on simulations as well, that such drifts are in practice inseparable from the gravity signal which is to be determined. Based on this finding, several accelerometer calibration methods are developed, aiming at the reduction of in-flight accelerometer drifts. In particular, thermal effects are shown to be the predominant error source. The proposed calibration methods are evaluated on real data, taken from five different airborne gravity campaigns. The common airborne gravimetry evaluation methods are summarised and discussed. An IMU-based gravity measurement accuracy of approximately $\SI{1e-5}{m/s^2}$ is verified, being equal or even superior compared to the achievable accuracy of mechanical spring-gravimeters under comparable conditions, which are still the predominant instrumentation for airborne gravimetry.
| Typ des Eintrags: | Dissertation | ||||
|---|---|---|---|---|---|
| Erschienen: | 2016 | ||||
| Autor(en): | Becker, David | ||||
| Art des Eintrags: | Erstveröffentlichung | ||||
| Titel: | Advanced Calibration Methods for Strapdown Airborne Gravimetry | ||||
| Sprache: | Englisch | ||||
| Referenten: | Becker, Prof. Dr. Matthias ; Forsberg, Prof. Dr. René | ||||
| Publikationsjahr: | Oktober 2016 | ||||
| Ort: | Darmstadt | ||||
| (Heft-)Nummer: | 51 | ||||
| Reihe: | Schriftenreihe der Fachrichtung Geodäsie, TU Darmstadt | ||||
| Datum der mündlichen Prüfung: | 1 September 2016 | ||||
| URL / URN: | http://tuprints.ulb.tu-darmstadt.de/5691 | ||||
| Kurzbeschreibung (Abstract): | Airborne gravimetry is the determination of the Earth's gravity field, using aircraft as mobile measurement platforms. For such measurements, there exist two predominant types of instrumentation: 1. Mechanical spring gravimeters, which are mounted on a gimballed platform in order to maintain a constant sensor orientation during the flight, aligned with the local vertical of the gravity field; 2. aircraft body-fixed 'strap-down' Inertial Measurement Units (IMU), containing each one sensor triad of accelerometers and gyroscopes. While IMUs are commonly designed for navigation applications, they also turn out to have several practical advantages also for gravimetric applications, compared to the more established platform-stabilised spring-gravimeters. In particular advantageous are the lower space and energy consumption, the autonomous operation during the flights, the lower sensitivity to turbulence, and the considerably lower acquisition costs. This thesis is a contribution to the improvement of kinematic, IMU-based gravimetry (denoted as \emph{strapdown gravimetry}). In practice, the predominant source of errors of such systems arises from uncompensated accelerometer drifts. It is shown theoretically, and based on simulations as well, that such drifts are in practice inseparable from the gravity signal which is to be determined. Based on this finding, several accelerometer calibration methods are developed, aiming at the reduction of in-flight accelerometer drifts. In particular, thermal effects are shown to be the predominant error source. The proposed calibration methods are evaluated on real data, taken from five different airborne gravity campaigns. The common airborne gravimetry evaluation methods are summarised and discussed. An IMU-based gravity measurement accuracy of approximately $\SI{1e-5}{m/s^2}$ is verified, being equal or even superior compared to the achievable accuracy of mechanical spring-gravimeters under comparable conditions, which are still the predominant instrumentation for airborne gravimetry. |
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| Alternatives oder übersetztes Abstract: |
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| Freie Schlagworte: | Strapdown, IMU, inertial measurement unit, gravimetry, airborne gravimetry, calibration, thermal calibration, system analysis, observability, estimability, error propagation analysis | ||||
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| URN: | urn:nbn:de:tuda-tuprints-56917 | ||||
| Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 550 Geowissenschaften | ||||
| Fachbereich(e)/-gebiet(e): | 13 Fachbereich Bau- und Umweltingenieurwissenschaften 13 Fachbereich Bau- und Umweltingenieurwissenschaften > Institut für Geodäsie 13 Fachbereich Bau- und Umweltingenieurwissenschaften > Institut für Geodäsie > Physikalische Geodäsie und Satellitengeodäsie |
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| Hinterlegungsdatum: | 30 Okt 2016 20:55 | ||||
| Letzte Änderung: | 03 Jun 2018 21:28 | ||||
| PPN: | |||||
| Referenten: | Becker, Prof. Dr. Matthias ; Forsberg, Prof. Dr. René | ||||
| Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 1 September 2016 | ||||
| Schlagworte: |
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