Research

Our research areas are diverse. There are several sub research groups in our lab.

• Formation Flight & GNSS Research Group
• Systems Engineering & AI Research Group
• Orbit Research Group
• Optical Communication Research Group

Formation Flight & GNSS Research Group

• FF & GNSS RG is a research group to study Formation Flying and Global Navigation Satellite System.
• FF is a technology to control multiple satellites cooperatively, and it can overcome the size limit of a single satellite and realize new advanced space missions. We primarily focus on accurate FF and massive FF. We also propose several FF missions with micro-satellite to realize actual FF missions.
• GNSS is a navigation system widely used all over the world. We focus on the study of precise orbit determination and prediction of GNSS satellites and the study of new GNSS systems with micro-satellites. We also study GNSS applications in space for advanced space missions like FF.

Systems Engineering & AI Research Group

The SE/AI research group studies systems engineering, artificial intelligence, and their applications to space development. Systems engineering is “a transdisciplinary and integrative approach to enable the successful realization, use, and retirement of engineered systems” (INCOSE). Specifically, we consider a satellite as a system and analyze how its functions are realized. Conversely, we also analyze and decompose the functional requirements for a satellite and study methods to efficiently design, develop, test, and operate the system to achieve them. On the other hand, in artificial intelligence, we study how to design spacecraft trajectories and onboard autonomy using machine learning methods such as deep learning, reinforcement learning, and regression analysis.

Orbit Research Group

• Orbit RG is a research group to study spacecraft trajectory design and orbit determination.
• For a spacecraft traveling to a celestial body, orbit is very important in order to save the fuel and shorten the transition time. Orbit design is the first step in planning a space mission, as it affects the fuel requirements of the spacecraft, the performance of its mission observations, and even the satellite system itself.
• The group is studying the optimal orbit in terms of fuel, time, scientific observation, etc. under certain realistic constraints such as resource constraints of nano-satellite systems. The topic is also about robust orbit design methods against errors in control and dynamics.
• Orbit determination is the process of determining the position of a spacecraft using measurements of distance and velocity between the ground and the satellite. The information is mainly obtained by radio waves. Orbit determination is essential for the exchange of information between ground antennas and satellites. In particular, orbit determination using radio waves with a spacecraft in deep space requires a certain amount of time and cost using a limited number of large antennas. On the other hand, the number of deep space exploration missions is expected to increase due to the development of nano-satellites in recent years, and there is a concern that the balance between supply and demand for large antennas will be disrupted.
• This research group is studying how to reduce dependence on ground stations by focusing not only on radio signals but also on optical signals, and by integrating orbit design and orbit determination, which have been considered separately in the past.

Optical Communication Research Group

• Optical Communication RG is involved in research and development regarding technical challenges for applying space optical communication technology to small satellites and spacecrafts.
• Traditional satellite communication primarily uses radio waves, but space optical communication, which uses light with shorter wavelengths and higher frequencies than radio waves, is being actively researched and developed in various countries. This is because it promises to achieve both miniaturization of communication antennas and improvement in communication capacity.
• This Research Group specifically aims to apply optical communication to small satellites weighing less than 100kg. We are tackling technical challenges in various fields, including control of direction, structure, and optics, towards the realization of small satellites with optical communication systems.
• Additionally, we are simultaneously doing research on issues related to how ultra-small optical communication satellites will be utilized in the future, such as routing methods in networks using groups of small optical communication satellites.
• The above research and development activities are closely linked to multiple actual projects being conducted in collaboration with external companies/organizations.