Calibrating the GOCE accelerations with star sensor data and a global gravity field model |
| |
| Authors: | Sietse Rispens Johannes Bouman |
| |
| Institution: | 1.SRON Netherlands Institute for Space Research,Utrecht,The Netherlands;2.Deutsches Geod?tisches Forschungsinstitut (DGFI),Munich,Germany |
| |
| Abstract: | A reliable and accurate gradiometer calibration is essential for the scientific return of the gravity field and steady-state
ocean circulation explorer (GOCE) mission. This paper describes a new method for external calibration of the GOCE gradiometer
accelerations. A global gravity field model in combination with star sensor quaternions is used to compute reference differential
accelerations, which may be used to estimate various combinations of gradiometer scale factors, internal gradiometer misalignments
and misalignments between star sensor and gradiometer. In many aspects, the new method is complementary to the GOCE in-flight
calibration. In contrast to the in-flight calibration, which requires a satellite-shaking phase, the new method uses data
from the nominal measurement phases. The results of a simulation study show that gradiometer scale factors can be estimated
on a weekly basis with accuracies better than 2 × 10−3 for the ultrasensitive and 10−2 for the less sensitive axes, which is compatible with the requirements of the gravity gradient error. Based on a 58-day data
set, scale factors are found that can reduce the errors of the in-flight-calibrated measurements. The elements of the complete
inverse calibration matrix, representing both the internal gradiometer misalignments and scale factors, can be estimated with
accuracies in general better than 10−3. |
| |
| Keywords: | GOCE Gradiometer Accelerations Calibration Star sensor Global gravity field model |
| 本文献已被 SpringerLink 等数据库收录！ |
|
