DOI: 10.5281/zenodo.15099750
title: GRACE-FO LRI1B HUST V01 Dataset

description: Note: Based on user feedback and further validation, we have optimized and improved the dataset. The new version is available at: https://zenodo.org/records/18574954. The current page hosts the old version (DOI: 10.5281/zenodo.15099750), which is no longer recommended for use. Please download the new version directly.

 

The Laser Ranging Interferometer (LRI) onboard the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) achieves inter-satellite distance measurements with nanometer precision, improving measurement accuracy by approximately three orders of magnitude compared to traditional K/Ka Band Microwave Ranging system (KBR), thereby establishing an unprecedented level of precision for satellite gravimetry missions.

 

The National Gravitation Laboratory at Huazhong University of Science and Technology (HUST) has independently developed the LRI1B data product—HUST LRI1B V01. This dataset incorporates innovative optimizations in critical technical aspects such as phase anomaly processing and time correction. Compared with the latest official product (JPL LRI1B RL04) and relevant research products (AEI LRI1B V54 and SYSU LRI1B S10), HUST LRI1B V01 achieves inter-satellite range-rate precision and time-variable gravity field recovery performance on par with AEI LRI1B V54 and SYSU LRI1B S10, while all three significantly outperform JPL LRI1B RL04.

 

The dataset covers the complete LRI measurement data from the GRACE-FO mission period (June 14, 2018 – June 30, 2023) and can be used for scientific research applications such as gravity field recovery, Mascon solution calculation, and Line of Sight Gravity Differences (LGD). In the future, as subsequent GRACE-FO Level 1A data are released, the dataset will be continuously updated and refined. We invite the academic community to use this dataset and provide feedback for further improvement.

 

We gratefully acknowledge the provision of GRACE-FO Level-1A and Level-1B data by the Jet Propulsion Laboratory (JPL), and the LRI1B data products together with their processing methodologies by the LRI teams from the Albert Einstein Institute (AEI) and Sun Yat-sen University (SYSU). This work was supported in part by the National Natural Science Foundation of China (No. 42422403), in part by the National Key Research and Development Program of China (No. 2023YFC2907003, 2023YFC2205501, 2023YFC2206700), and in part by the Fundamental Research Funds for the Central Universities (HUST:No.2025JYCXJJ062). 

 

 

Appendix A. LRI1B File and Data Format Description

This data product follows the official GRACE-FO LRI1B data format specification. Each file consists of two parts: a YAML-formatted file header and a space-delimited data body.

 

1. File Structure

The file header begins with header and ends with # End of YAML header, and is written in YAML format. It includes essential metadata such as: the number of data records, the start and end times of the data, descriptions and units of each variable, and processing version information.

The data body contains the actual observation records. Each row corresponds to one epoch and includes values arranged in the same order as defined in the file header. Columns are separated by spaces. For detailed descriptions of each variable, please refer to the annotations in the file header as well as the official GRACE-FO LRI1B format documentation in reference [4].

 

2. Data Format References

The structure and content of this product are based on the following official and research data products:

JPL LRI1B RL04 official product

SYSU LRI1B S10 product

AEI LRI1B V54 product

 

3. Notes on Special Variables

Column 12 (K_A_SNR) and Column 14 (K_B_SNR) represent the CNR of GRACE-FO satellites C and D, respectively. These two columns of data are inherited directly from the JPL LRI1B RL04 product.

Column 15 (Time Shift) indicates the estimated time offset between the LRI and KBR systems. The unit is nanoseconds.

Column 16 (Quality Flag) is used to indicate the quality status of each epoch. It is encoded using an 8-bit binary flag, where each bit represents a specific condition:



Bit 0: Indicates a phase anomaly, which includes phase jumps, single event upsets, channel cycle slips, momentum transfer events, and effects during sun-blinding periods.

Bit 1: Indicates phase interpolation, meaning the data for that epoch is interpolated rather than directly observed.

Bits 2–7: Currently undefined and reserved for future use.