IGCP 565 Project Workshop

IGCP 565 Workshop 1: Science of geodetic monitoring of the hydrological cycle

Abstract:

High-resolution analysis of GRACE sensor data and lessons for follow-on satellite missions
Jakob Flury
University of Texas Center for Space Research

Progress in the determination of gravity time variations from GRACE and follow-on missions requires the full exploitation of measurement accuracy of the involved extremely sensitive sensors. To achieve this goal, the in-orbit sensor accuracy has to be verified, and disturbances exceeding the sensor noise have to be modeled and understood. On GRACE, several types of satellite-induced disturbances such as switching spikes and micro-vibrations have been found which significantly exceed the noise of the GRACE sensors. Sensors of follow-on missions with increased measurement accuracy will be even more sensitive to disturbances. We show that high-resolution GRACE observation time series together with quality satellite house-keeping data allow for a step-by-step identification and reduction of satellite-induced disturbances. Further on, we discuss approaches for mutual validation of inter-satellite ranging, GPS, and accelerometer measurements, using test signals due to events such as penumbra transitions of the satellites. Conclusions for the design of sensor-platform configurations will be discussed.