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Mohammed Irfan Rashed,Seunghan Lim,Hyochoong Bang 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10
This paper deals with the mathematical analysis, testing and necessary assessment on the source of drift was done both statistically as well as experimentally for accurate attitude determination of specifically Nano-satellites using Micro-Electro Mechanical Systems based three-axis gyroscopes. In the recent times, the gyroscope application has been a major concern during the important missions due to their inability to transfer data efficiently and effectively during the mission period due to which there had been immense data loss and in some cases even failure. Especially, the MEMS based low cost gyroscopes are of an important concern due to their high bias drift rate in the space environment. Hence, in order to study, simulate, test, analyze and evaluate the performance of the three-axis MEMS based gyroscope, intensive research was carried out. A potential quaternion based mathematical model was simulated to scrutinize the bias drift variation in the 3-axis gyroscope and then a testing of a unique MEMS based 3-axis gyroscopes was done to practically learn and understand the variation and actual source of drift at different situations under operation. After the testing, the data was compiled and the necessary basic bias drift analysis was done. Noting the results of simulations and testing, some significant conclusions were made.
Mohammed Irfan Rashed,Donghun Lee,Hyochoong Bang 제어로봇시스템학회 2013 제어로봇시스템학회 국제학술대회 논문집 Vol.2013 No.10
This paper deals with the critical arithmetic analysis of the Attitude Determination System design of Nanosatellites considering the sensor combination model considering finely-selected MEMS based Gyroscopes, Magnetometers and Sun Sensors respectively. Though the competency for achieving higher accuracy for proper positioning of a Nano-satellite is being experimented across the globe effectively, but still there is an absolute need for recognizing the appropriate methodology to enhance their performance withstanding the harsh space environment at different instances. The essential parameters for both the true model and the measurement model are studied and simulated utilizing advanced techniques for obtaining accurate attitude along three axes accordingly. Two distinct attitude determination configurations have been discussed, simulated and compared with significant reasoning being described. One with the combination of Extended Kalman Filter (EKF) and TRIAD algorithm and other with Unscented Kalman Filter (UKF) and TRIAD algorithm. Using these configurations, the critical aspects like power consumption and sensor operation at diverse functioning situations are being conferred. The results show significant variation in accuracy deriving important conclusions on using distinct configuration on board statistically. This research is essentially done to obtained statistical results on unique sensor fusion concept with a different configuration applied which will be practically tested in near future.
나노위성의 효과적인 자세 추정을 위한 3축 MEMS 자이로의 온도 와 오류 특성 실험 및 보상 분석 연구
Mohammed Irfan Rashed,Donghun Lee,Hyochoong Bang 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.11
This paper presents a detailed study, experimentation and compensation analysis of temperature characteristics of 3-axis MEMS based Gyroscopes used for the angular estimation basically a most important part of the sensor fusion in Attitude Determination System (ADS) specifically designed for the purpose of Nano-satellites. The most critical parameters adding the bias in the measurement of these Gyroscopes are observed to be the temperature fluctuations and the error characteristics which are said to be Bias stability and the Random-walk noise respectively. Hence these parameters are studied and then sensors are tested in different temperature ranges for various intervals of time to examine their durability and behavior. After the temperature test, the error characteristics are studied using suitable technique. In conclusion, a detailed error and thermal analysis is done to emphasize the important parameters responsible for the biases due to error and temperature characteristics using the Unscented Kalman Filter (UKF) and possible solutions are discussed.
Strategies for Autonomous Small-satellite Technology Transfer from LEO to CisLunar Space
Mohammed Irfan Rashed,HyoChoong Bang 제어로봇시스템학회 2022 제어로봇시스템학회 국제학술대회 논문집 Vol.2022 No.11
For the NewSpace era, it is inevitable to think technologies which can be dually used in LEO (as usual) but also supporting dynamic GATEWAY mission to Moon and beyond. This paper emphasizes to strategize the creative techniques to transfer the autonomous technologies developed for LEO to Moon’s CisLunar Space. The key role of the autonomy in deep space is also discussed with systematic and well-defined techniques is need of the hour. Mining and other support to the astronauts will be prominent during the Artemis mission and need utmost strategic delivery of required information and resources. This paper will open a unique point of view to redefine space norms facilitating low-cost small satellite technology transfer and optimization of trajectories with updated technologies and transportation methods from LEO to CisLunar Space efficiently.
이동헌,Mohammed Irfan Rashed,방효충 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.11
본 논문에서는 인공위성에 탑재된 안테나에 대하여 지상국과의 교신이 가능한 김발 명령 생성 연구를 수행하였다. 안테나 김발각의 궤적 설계 과정에서는 우주비행체의 궤도 정보 및 자세 프로파일을 이용하였으며, 안테나의 빔폭 등을 고려하여, 실용적인 면에서 적용이 가능한 김발 궤적을 생성하였다. 기존의 접근법과 달리, 궤적최적화 방법을 적용하여, 안테나 김발 시스템의 제한된 각속도 및 각가속도 범위를 만족하면서, 우주비행체에 임무를 수행할 수 있도록 안테나 김발 명령을 생성하였다. This paper considers a problem of gimbal command design to communicate with ground-station. In the problem, orbit and attitude data of a spacecraft are used, and a field of view of the Antenna system is also considered, so that designed gimbal histories can make it possible to communicate with ground station. Compared to previous works, a trajectory optimization technique is used, in which mechanical constraints of maximum gimbal"s angular velocity and angular acceleration are taken into account as inequality constraints. Through a numerical scenario, it is demonstrated that the designed gimbal histories are applicable from the practical points of view.
Muhammad Imran,Muhammad Irfan,Muhammad Yaseen,Naser Rasheed 한국작물학회 2018 Journal of crop science and biotechnology Vol.21 No.5
Low-use efficiency of phosphatic fertilizers in calcareous soils is a serious issue worldwide resulting in sub-optimal phosphorus (P) availability to plants. Polymer-coated fertilizers provide an effective solution to enhance P-use efficiency in such soils by reducing fixation and ensuring slow and consistent phosphate supply to growing plants. The present field experiment was conducted to evaluate the effectiveness of commercial diammonium phosphate (DAP) fertilizer and coated DAP with polymer and/or glycerin to improve plant growth, grain yield, and P-use efficiency of wheat crops. The results revealed that application of 100% recommended rate of glycerin + polymer coated DAP significantly enhanced plant height, number of fertile tillers m-2, 1000-grain weight, grain yield, and P uptake in comparison with commercial DAP fertilizer. Moreover, polymer coated DAP produced comparatively better results than glycerin coated DAP alone. The sustainable yield index, P agronomic and recovery efficiencies were also improved and recorded higher with glycerin + polymer-coated DAP fertilizer at 100% of the recommended rate. Furthermore, higher P uptake, P recovery, and agronomic efficiencies in response to coated DAP were found responsible for sustainable wheat yield. Overall, the glycerin + polymer-coated DAP with 75% recommended rate showed statistically identical results to uncoated DAP with 100% recommended rate. The amount of applied P vulnerable to fixation was significantly reduced with the application of glycerin + polymer-coated DAP thereby resulting in improved plant growth, grain yield, and P-use efficiency of wheat crops.
An Antenna Tracking Profile Design for Communication with a Ground station
Donghun Lee,Kyung-Min Lee,Mohammed Irfan Rashed,Hyochoong Bang 한국항공우주학회 2013 International Journal of Aeronautical and Space Sc Vol.14 No.3
In order to communicate with a ground station, the tracking profile design problem for a directional antenna system is considered. Because the motions of the gimbal angles in the antenna system affect the image quality, the main object is to minimize the motion of the gimbal angles during the satellite’s imaging phase. For this goal, parameter optimization problems in the imaging and maneuver phases are formulated separately in the body-frame, and solved sequentially. Also, several mechanical constraints, such as the limitation of the gimbal angle and rate, are considered in the problems. The tracking profiles of the gimbal angles in the maneuver phases are designed with N-th order polynomials, to continuously connect the tracking profiles between two imaging phases. The results confirm that if the vector trace of the desired antenna-pointing vector is within the antenna’s beam-width angle, motions of the gimbal angles are not required in the corresponding imaging phase. Also, through numerical examples, it is shown that motion of the gimbal angles in the imaging phase can be minimized by the proposed design process.