研究者詳細 - 趙　孟佑

論文 - 趙　孟佑

分割表示643 件中 1 - 20 件目／全件表示 >>

On-Orbit Experimental Result of a Non-Deployable 430-MHz-Band Antenna Using a 1U CubeSat Structure 査読有り国際誌

Nakayama D., Yamauchi T., Masui H., Kim S., Toyoda K., Malmadayalage T.L.D., Cho M.

Electronics (Switzerland) 11 ( 7 ) 2022年04月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

1U CubeSats often use the 430-MHz band for communication due to their size and power limitations, and half-wavelength dipole antennas are employed. A 430-MHz-band dipole antenna requires a deployable structure for a 1U CubeSat. However, a 1U CubeSat has a small volume margin for redundant systems, so the antenna deployment system can be a single point of failure. In this paper, the 1U CubeSat structure itself was used as an antenna. As a sub-mission of the BIRDS-4 project, three 1U CubeSats (GuaraniSat-1, Maya-2, and Tsuru) demonstrated this antenna structure. The results of the ground tests showed a maximum gain of −5.7 dBi with the flight model. These satellites were deployed from the International Space Station on 14 March 2021. Radio signals were alternately transmitted from the dipole antenna and the structure antenna onboard Tsuru for on-orbit demonstration on 15 December 2021, and the received signal strength on the ground was compared using RTL-SDR, SDR# and several codes. The ground station was able to receive both dipole and structure CW signals. The received power strength indicates that a gain of −8.1 dBi is being demonstrated with the structure antenna.

DOI： 10.3390/electronics11071163

Scopus

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Experimental study on photodiode array sensor aided MEMS fine steering mirror control for laser communication platforms 査読有り国際誌

Ishola F., Cho M.

IEEE Access 9 100197 - 100207 2021年01月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

Line-of-sight laser communication application scenarios are numerous including land, mobile, maritime, airborne and space platforms for conventional and tactical utilization. However, beam pointing and stabilization are complicated in dynamic systems such as orbiting satellite to ground receiver, drones, aircrafts and metropolitan free-space optical links vulnerable to natural and artificial disturbances. Small Satellite platforms such as CubeSats are even more challenging due to their limited size and on-board resources. This paper presents an experimental study on a feedback photodiode array sensor assisted control of a one-axis micro-electromechanical (MEMS) fine steering mirror stabilizing a laser communication link on an optical bench in the laboratory. Disturbance profiles similar to vibrations on dynamic platforms are induced into the setup using an electrodynamic vibration machine to test the efficacy of the MEMS fine steering control mechanism. The Photodiode Array (PDA) sensor collocated with an Avalanche Photodiode at the receiving section provides sustained information about the transmitter's movements and beam displacements while the received optical signal strength is continuously monitored. The feedback signals are transmitted to the FSM controller via a radio link. We demonstrate the capacity to stabilize a laser beam transmission in the presence of external disturbances and platform movements using a PDA sensor assisted control.

DOI： 10.1109/ACCESS.2021.3096816

Scopus

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Lessons learned and initial results from birds ground station network 査読有り国際誌

Jirawattanaphol A., Cho M.

Advances in the Astronautical Sciences 173 643 - 651 2020年01月

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

Communication time between satellites in the LEO and ground stations are usually limited. Increasing communication data rate may not be an option as it may increase satellite cost and impose more requirements on power generation. Using ground station network for constellation of satellites increases the communication window between satellites and ground stations. BIRDS ground station network (GSN) was established in 2015 to support the missions of BIRDS-1 satellites constellation as part of an educational satellite program named BIRDS at Kyushu Institute of Technology (Kyutech). The GSN propagated into supporting the missions of BIRDS-2 and BIRDS-3 satellites and other small satellites operating on VHF/UHF. Currently, the BIRDS GSN has fifteen member countries with ground stations installed in each country across the world in South America, Africa and Asia connected by internet and managed by Kyutech. This paper presents challenges and lessons learned in establishing ground stations in participating countries such as the insufficiency of technical skills and knowledge to set up and operate the local ground station. The BIRDS GSN has been successful to increase the time resolutions and significantly reduced time to download images from BIRDS-3 satellites.

Scopus

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On-Orbit Magnetometer Data Calibration Using Genetic Algorithm and Interchangeability of the Calibration Parameters 査読有り国際誌

Withanage D.C., Teramoto M., Cho M.

Applied Sciences (Switzerland) 13 ( 11 ) 2023年06月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

Magnetometers are important sensors with applications in the attitude determination and control systems of satellites. CubeSats have certain limitations related to power, mass, and volume. Due to this, CubeSat magnetometers are not separated from other electrical circuits inside the satellite. Thus, it is important to calibrate the magnetometer, simulating operating conditions while the satellite is running before the launch. However, due to the limited facilities, not every CubeSat is able to calibrate its magnetometers properly on the ground. This study focuses on the calibration of on-orbit magnetometer data observed by BIRDS-3 CubeSats with a genetic algorithm. High oscillations in the total magnetic field were found in the on-orbit magnetic field data measured by magnetometers inside BIRDS-3 CubeSats. Nine unknowns, scaling factors, non-orthogonal angles, and offsets are identified with the genetic algorithm. This paper discusses the factors that affect the high oscillations in the measured total magnetic field data. For the calibration, we used magnetic field data similar to those of a model magnetic field, as the deviation is smaller. This paper presents the accuracy of determining unknowns using the genetic algorithm, as well as the interchangeability of the answers with additional orbit data from the same satellite. This method can be used in the future to calibrate magnetometers inside CubeSats before or after launch.

DOI： 10.3390/app13116742

Scopus

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Integration of a UHF Fractal Antenna into a 1U CubeSat for Low-Earth Orbit Mission 査読有り

Raynell A. Inojosa, Celso B. Co, and Mengu Cho

International Conference on Advances in Communication Technology and Computer Engineering 2023年02月

Revision of ISO-19683 for constellation testing 査読有り

Mengu Cho

5th International Workshop on Lean Satellite 2023年01月

UNISEC-Global - Past, Present and Future 査読有り国際誌

Kawashima R., Ibrahim M.K., Steyn H., Nakasuka S., Aslan A.R., Cho M.

Proceedings of 10th International Conference on Recent Advances in Air and Space Technologies, RAST 2023 2023年01月

担当区分：責任著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

University Space Engineering Consortium (UNISEC)-Global has contributed to promoting and supporting practical space projects at the university level worldwide. Initially., the university consortium activities started in Japan in 2002., and currently., it has 24 Local Chapters (LCs) and 63 Points Of Contact (POC) worldwide. UNISEC-Global aims to create a world where university students in all countries/regions can participate in practical space projects and provide educational programs such as CanSat/CubeSat Leader Training Program (CLTP), Mission Idea Contest (MIC) for nano/micro satellite utilization. Also, it provides a forum where people can exchange information, knowledge, and views by organizing in-person and virtual conferences/meetings. Recent changes in the space situation caused by mega-constellation missions have impacted university satellite projects. UNISEC-Global needs diverse experts' support, and restructuring the organization is essential to involve all stakeholders. Given the problematic space situations, future directions are discussed, and three proposals, creating working groups, empowering Local Chapters, and launching UNISEC constellation mission(s), are presented.

DOI： 10.1109/RAST57548.2023.10197659

Scopus

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BIRDS Bus Open-Sourcing Activity 査読有り

布施哲人,趙孟佑

5TH INTERNATIONAL WORKSHOP ON LEAN SATELLITE 2023年01月

Design improvement of a thermoelectric device-based thermal vacuum chamber 査読有り

Mattei GIULIO, Joseph Ampadu OFOSU, Hirokazu MASUI, and Mengu CHO

5th International Workshop on Lean Satellite 2023年01月

Onboard Image Classification for Nanosatellites to Improve Data Downlink Efficiency 査読有り

Keenan Chatar, Kitamura Kentaro, Abhas Maskey and Mengu Cho

10th International Symposium on Applied Engineering and Sciences 2022年12月

Exploiting Fractal Geometry in the Design of a UHF Patch Antenna for Low-Earth Orbit Nanosatellite Applications 査読有り

Raynell A. Inojosa, Celso B. Co, and Mengu Cho

2022 Graduate Research Forum for Technology, Engineering, and Computing (Graf-TEC 2022) 2022年12月

On-orbit Electrical Power System Dataset of 1U CubeSat constellation 査読有り

Adolfo Javier Jara Cespesdes; Pooja Lepcha; Sangkyun Kim; Hirokazu Masui; Takashi Yamauchi; George Maeda; Mengu Cho

Data in Brief 2022年12月

Electrodynamic Analysis of a Geometry-Oriented Antenna for Low-Earth Orbit CubeSat 査読有り

Raynell A. Inojosa, Celso B. Co, and Mengu Cho,

2022 IEEE Transdisciplinary-Oriented Workshop for Emerging Researchers (TOWERS) 2022年11月

Surface Potential Measurement with Pockels Effect Under Electron Beam and Vacuum Ultraviolet 査読有り国際誌

Toyoda K., Kose S., Cho M.

Journal of Spacecraft and Rockets 59 ( 6 ) 2202 - 2205 2022年11月

Assessment of Intra-Urban Heat Island in a Densely Populated City Using Remote Sensing: A Case Study for Manila City 査読有り国際誌

Purio M.A., Yoshitake T., Cho M.

Remote Sensing 14 ( 21 ) 2022年11月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

Changes in the environment occur in cities due to increased urbanization and population growth. Sustainable Development Goal (SDG) 11 is intrinsically linked to the environment, one facet of which is the need for universal access to secure, inclusive, and accessible green and public places. As urban heat islands (UHI) have the potential to negatively influence cities and their residents, existing resources and data must be used to identify and quantify these effects. To address this, we present the use of satellite-derived (2013–2022) and meteorological data (2014–2020) to assess intra-urban heat islands in Manila City, Philippines. The assessment includes (a) understanding the temporal variability of air temperature measurements and outdoor thermal comfort based on meteorological data, (b) comparative and correlative analysis between common Land-Use Land Cover indicators (Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI) and Normalized Difference Built-up Index (NDBI)) and Land Surface Temperature (LST), (c) spatial and temporal analysis of LST using spatial statistics techniques, and (d) generation of an intra-urban heat island (IUHI) map with a recommended class of action using a suitability analysis model. Finally, the areas that need intervention are compared to the affected population, and suggestions to enhance the thermal characteristics of the city and mitigate the effects of UHI are established.

DOI： 10.3390/rs14215573

Scopus

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Design and environmental testing of imaging payload for a 6U CubeSat at low Earth orbit: KITSUNE mission. 査読有り

Muhammad Hasif Bin Azami, Necmi Cihan Örger, Victor Hugo Schulz, Takashi Oshiro, Jose Rodrigo Cordova Alarcon, Abhas Maskey, Kazuhiro Nakayama, Yoshiya Fukuda, Kaname Kojima, Takashi Yamauchi, Hirokazu Masui, Mengu Cho

Frontiers in Space Technologies 2022年11月

SmallSat NanoSat strategy at Kyushu Institute of Technology 査読有り

布施哲人,趙孟佑

International Conference on Aerospace Science and Technology 2022 2022年11月

Open-Sourcing of CubeSat Bus for Capacity Building aimed to Acquire Original Space Development Capability 査読有り

布施哲人,趙孟佑

JOINT 3RD IAA LATIN AMERICAN SYMPOSIUM ON SMALL SATELLITES AND 5TH IAA LATIN AMERICAN CUBESAT WORKSHOP 2022年11月

Revision Strategy of Lean Satellite Testing Standard ISO-19683 査読有り

Mengu Cho, Joseph Ofosu, Takashi Yamauchi, Hirokazu Masui

11th Nanosatellite Symposium 2022年10月

BIRDS-4 1U CubeSat Missions and On-Orbit Results 査読有り

Hari Ram Shrestha, BIRDS-4 Project Members, George Maeda, Sangkyun Kim1, Hirokazu Masui1, Takashi Yamauchi1, Mengu Cho

11th Nano-Satellite symposium 2022年10月

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