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Drift reduction in strapdown airborne gravimetry using a simple thermal correction
Abstract Previous work has shown, that strapdown airborne gravimeters can have a comparable or even superior performance in the higher frequency domain (resolution of few kilometres), compared to classical stable-platform air gravimeters using springs, such as the LaCoste and Romberg (LCR) S-gravimeter. However, the longer wavelengths (tens of kilometres and more) usually suffer from drifts of the accelerometers of the strapdown inertial measurement unit (IMU). In this paper, we analyse the drift characteristics of the QA2000 accelerometers, which are the most widely used navigation-grade IMU accelerometers. A large portion of these drifts is shown to come from thermal effects. A lab calibration procedure is used to derive a thermal correction, which is then applied to data from 18 out of 19 flights from an airborne gravity campaign carried out in Chile in October 2013. The IMU-derived gravity closure error can be reduced by 91 % on average, from 3.72 mGal/h to only 0.33 mGal/h (RMS), which is an excellent long-term performance for strapdown gravimetry. Also, the IMU results are compared to the LCR S-gravimeter, which is known to have an excellent long-term stability. Again, the thermal correction yields a significant reduction of errors, with IMU and LCR aerogravity results being consistent at the 2 mGal level.
Drift reduction in strapdown airborne gravimetry using a simple thermal correction
Abstract Previous work has shown, that strapdown airborne gravimeters can have a comparable or even superior performance in the higher frequency domain (resolution of few kilometres), compared to classical stable-platform air gravimeters using springs, such as the LaCoste and Romberg (LCR) S-gravimeter. However, the longer wavelengths (tens of kilometres and more) usually suffer from drifts of the accelerometers of the strapdown inertial measurement unit (IMU). In this paper, we analyse the drift characteristics of the QA2000 accelerometers, which are the most widely used navigation-grade IMU accelerometers. A large portion of these drifts is shown to come from thermal effects. A lab calibration procedure is used to derive a thermal correction, which is then applied to data from 18 out of 19 flights from an airborne gravity campaign carried out in Chile in October 2013. The IMU-derived gravity closure error can be reduced by 91 % on average, from 3.72 mGal/h to only 0.33 mGal/h (RMS), which is an excellent long-term performance for strapdown gravimetry. Also, the IMU results are compared to the LCR S-gravimeter, which is known to have an excellent long-term stability. Again, the thermal correction yields a significant reduction of errors, with IMU and LCR aerogravity results being consistent at the 2 mGal level.
Drift reduction in strapdown airborne gravimetry using a simple thermal correction
Becker, David (author) / Nielsen, J. Emil (author) / Ayres-Sampaio, Diogo (author) / Forsberg, René (author) / Becker, Matthias (author) / Bastos, Luísa (author)
Journal of Geodesy ; 89
2015
Article (Journal)
English
BKL:
38.73
Geodäsie
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