Precise Orbit Determination by using MADOCA on JSS3

JAXA Supercomputer System Annual Report February 2025-January 2026

Report Number: R25ER0800

Subject Category: Space Technology

Responsible Representative: Satoshi Kogure
Contact Information: Yui Ogawa(ogawa.yui@jaxa.jp)
Members: Sho Miyoshi, Tatsuya Nagano, Hideki Narita, Yui Ogawa, Masato Okeya, Takashi Tsuruta, Hiroshi Takiguchi, Makoto Watanabe

Abstract

Satellite Navigation Unit continuously generates and provides satellite orbit and clock products essential for precise positioning using MADOCA (Multi-GNSS Advanced Demonstration tool for Orbit and Clock Analysis) and are delivered to users via a network.

We also work jointly with the Geospatial Information Authority of Japan (GSI) as an IGS Analysis Center, contributing to the improvement of global positioning accuracy by supplying high‑precision products generated with MADOCA to the International GNSS Service (IGS).

On the JSS3, we aim to realize the computation for the long-term data analysis and simulation.

Reference URL

Please refer to https://ssl.tksc.jaxa.jp/madoca/public/public_index_en.html .

Reasons and benefits of using JAXA Supercomputer System

MADOCA's offline analysis function performs large‑scale batch processing using least‑squares estimation, based on GNSS observation data collected worldwide, to determine satellite orbits and clocks with high precision.

However, due to the enormous amount of observation data and the large number of estimation parameters involved, the resulting normal equations become very large, making computational load significant on general-purpose computers.

Therefore, to accelerate orbit and clock estimation, speed up product generation, and support stable international product distribution as an IGS Analysis Center, we are exploring the use of supercomputing resources.

Achievements of the Year

This fiscal year, we focused on addressing issues directly related to improving operational stability and ensuring product quality in MADOCA operations. The primary activities included:

- Investigation and root‑cause analysis of unidentified issues that occurred during MADOCA operations

- Parameter tuning to enhance the stability of estimation results

- Evaluation and performance verification of the internally developed derivative software (MADOCA+)

Through these efforts, we contributed to maintaining the continuous operational quality of MADOCA and ensuring the reliability of internationally distributed products.

Publications

N/A

Usage of JSS

Computational Information

Process Parallelization Methods: N/A
Thread Parallelization Methods: OpenMP
Number of Processes: 1
Elapsed Time per Case: 30 Minute(s)

JSS3 Resources Used

Fraction of Usage in Total Resources*1(%): 0.06

Details

Please refer to System Configuration of JSS3 for the system configuration and major specifications of JSS3.

Computational Resources
System Name	CPU Resources Used (Core x Hours)	Fraction of Usage*2(%)
TOKI-SORA	0.83	0.00
TOKI-ST	2442.76	0.00
TOKI-GP	0.00	0.00
TOKI-XM	0.00	0.00
TOKI-LM	0.01	0.00
TOKI-TST	479482.90	7.83
TOKI-TGP	0.00	0.00
TOKI-TLM	1109.44	7.03

File System Resources
File System Name	Storage Assigned (GiB)	Fraction of Usage*2(%)
/home	1024.00	1.64
/data and /data2	25600.00	0.17
/ssd	0.00	0.00

Archiver Resources
Archiver Name	Storage Used (TiB)	Fraction of Usage*2(%)
J-SPACE	0.00	0.00

*1: Fraction of Usage in Total Resources: Weighted average of three resource types (Computing, File System, and Archiver).

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.

ISV Software Licenses Used

ISV Software Licenses Resources
	ISV Software Licenses Used (Hours)	Fraction of Usage*2(%)
ISV Software Licenses (Total)	0.00	0.00

*2: Fraction of Usage：Percentage of usage relative to each resource used in one year.