In-orbit Demonstration of X-ray Pulsar Navigation with NinjaSat
Abstract
This study demonstrated the pulsar navigation capability of the CubeSat X-ray observatory NinjaSat, which is equipped with two Gas Multiplier Counters (GMCs). The GMCs are sensitive to the 2-50 keV energy band and have an effective area of 16 cm^2 per module at 6 keV. We verified the timing accuracy by observing the Crab Pulsar and confirmed stable timing performance within 100 microseconds. To demonstrate pulsar navigation, we applied a method that optimizes orbital parameters to maximize the significance of the pulsar X-ray pulse profile, known as the Significance Enhancement of Pulse-profile with Orbit-dynamics (SEPO) method. We observed the Crab Pulsar with a total exposure of approximately 100 ks at different epochs and analyzed the data transmitted to the ground. By comparing the optimized orbit with the satellite position derived from Global Positioning System data, we quantitatively evaluated the navigation performance. The results show that the position component along the Crab line of sight was consistently constrained within approximately 40 km, and the three-dimensional position error ranged from 27 to 370 km depending on the observation epoch. These results demonstrate the feasibility of applying a CubeSat-class X-ray observatory to pulsar navigation and provide the first experimental verification that the accuracy of the SEPO method depends on the seasonal geometry between the orbital plane and the pulsar direction.
Keywords
Cite
@article{arxiv.2602.14166,
title = {In-orbit Demonstration of X-ray Pulsar Navigation with NinjaSat},
author = {Naoyuki Ota and Takuya Takahashi and Toru Tamagawa and Tomoshi Takeda and Teruaki Enoto and Takao Kitaguchi and Wataru Iwakiri and Yo Kato and Masaki Numazawa and Tatehiro Mihara and Hiromitsu Takahashi and Chin-Ping Hu and Yuanhui Zhou and Keisuke Uchiyama and Yuto Yoshida and Syoki Hayashi and Arata Jujo and Sota Watanabe and Amira Aoyama and Satoko Iwata and Kaede Yamasaki and Soma Tsuchiya and Yosuke Nakano and Takayuki Kita and Mayu Ichibakase and Hiroki Sato and Hirokazu Odaka and Tsubasa Tamba and Kentaro Taniguchi},
journal= {arXiv preprint arXiv:2602.14166},
year = {2026}
}
Comments
22 pages, 9 figures, accepted for publication in JATIS