Basic Challenge 2
This challenge is very much similar to the basic challenge 1. The only difference here is the inclusion of the Laser Ranging data as an additional data stream for GRACE Follow-On mission. This challenge is mainly designed for beginners and interested students who would like to develop their own software for analyzing LRI data in the context of gravity field recovery from satellite data. More experience analysis centres should also find this challenge useful to test and verify their software for LRI data. The simulated data are kept very simple where only an Earth's gravity model is used to generate the orbit, the LRI and the KBR the inter-satellite ranging data. No other disturbing forces such as tidal forces and non-gravitational accelerations are included. The data are corrupted with simplified noise models and the participants are asked to estimate the gravity field coefficients (spherical harmonic coefficients) using the known approaches for gravity field recovery (acceleration approach, the energy balance approach, the classical approach etc.). We collect the solutions from all participants and compare them with the Earth's gravity field model which has been used for the simulation. The results of comparison will be published on this webpage and we also plan to publish and discuss the main findings in a journal paper or a technical report.
Even after the publication of the results, this challenge will be open for all interested students and new-comers of this field for a long time and they can compare their solutions with the published comparisons.
The simulated data provided for the second challenge are obtained using a numerical orbit integration in which only an Earth's gravity field is the effective force on the satellites. The gravity field model and its maximum degree used in the integration as well as the noise models used to corrupt the data remain hidden. The figure below illustrated the simulation scenario including the LRI data.
Submit Your Results
Submit your estimated spherical harmonic coefficients at the submission site by uploading your text file.
Use the following file format for the spherical harmonics coefficients: ICGEM gravity field model.
Please also take note of the order in the degree and order columns L and M and add all information concerning your results including processing strategy, constraints, constants etc. in the file header.