Article
Engineering, Aerospace
Ziyang Yu, Zhong Lu, Yiyang Guo, Ying Zhang, Guoping Lei
Summary: This study used Solar-Induced chlorophyll Fluorescence (SIF) as a proxy for vegetation photosynthesis and examined the impacts of climate conditions on vegetation photosynthesis. The results showed that 81.5% of China's areas exhibited an improving trend of vegetation photosynthesis. Agricultural technology contributed to the increase in vegetation photosynthesis in the southern regions, while overgrazing disturbance and coal mining activities led to vegetation deterioration in the Qinghai Tibet Plateau and Huang-Huai-Hai Plain.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Engineering, Aerospace
Dilek Kucuk Matci
Summary: Population growth and urbanization have been increasing rapidly in recent years. Urban growth leads to changes in land use/cover. This study proposes a new method to accurately map urban areas using remote sensing imagery. The proposed method achieves higher overall accuracy compared to existing methods and raw image bands.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Engineering, Aerospace
Nayana Shenvi, E. Chandrasekhar, Anurag Kumar, Hassanali Virani
Summary: This study proposes a deep learning-based model, ST-ResNet, for predicting TEC and evaluates its performance. The results demonstrate that the ST-ResNet model achieves high accuracy in TEC prediction and outperforms other commonly used models.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Engineering, Aerospace
E. C. Kalafatoglu Eyiguler, K. Pandey, A. D. Howarth, W. Holley, D. W. Danskin, G. C. Hussey, R. G. Gillies, A. W. Yau
Summary: The characteristics of a polarized radio wave detected by a spacecraft antenna depend on various factors such as the positions of the transmitting source and the spacecraft, the orientation of the antenna, the electric field of the incident wave, and the properties of the medium. Precise knowledge of the propagation direction and antenna orientation is essential for understanding the received signal. The study focuses on coordinated experiments between the Radio Receiver Instrument (RRI) on Swarm-E and a transmitter in Canada, and the methods developed are important for determining the true polarization characteristics of radio waves.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Engineering, Aerospace
Xiao Gao, Zongfang Ma, Minghan Shi, Qize Wang, Lisha Zhang, Hailong Zhang
Summary: The paper proposes an improved SICB piecewise correction model to remove systematic bias in the BeiDou navigation satellite system, and verifies its effectiveness through experimental results.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Engineering, Aerospace
Teng Zhang, Peng Shi, Ming Guo, Xiaokui Yue
Summary: This paper presents a novel strategy for rapid attitude stabilization of space robots after capturing unknown targets, reducing the impacts of residual momentum, uncertainties in inertial parameters, and observation noise. The approach utilizes dynamical coupling and an iterated extended Kalman filter to estimate the system's motion state and target's inertial parameters. Numerical simulations and Monte Carlo simulations are conducted to verify the validity and feasibility of the approach.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Engineering, Aerospace
Zheng Yang, Lei Qiao, Mingkun Su, Zhenhua Hu, Xuyang Teng, Jiayi Wang
Summary: This paper proposes an ionospheric foF2 prediction model GWO-ALSTM, which combines the Gray Wolf Optimization (GWO) algorithm and the attention mechanism based on the long short-term memory (LSTM) model. Through comparative analysis with other models, the results show that the GWO-ALSTM model outperforms other models in prediction accuracy. Additionally, comparative analysis of the diurnal variations of foF2 also indicates that the GWO-ALSTM model is closer to the observed values.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Engineering, Aerospace
Zheng Li, Fei Guo, Fade Chen, Zhiyu Zhang, Xiaohong Zhang
Summary: This study demonstrates for the first time the effect of geographical location on Cyclone Global Navigation Satellite System (CYGNSS) observables. It is found that the observables corresponding to the same wind speed vary with geographic location regularly. An improved method for Global Navigation Satellite System Reflectometry (GNSS-R) wind speed retrieval that considers geographical differences is proposed. The method divides the sea surface into different areas for independent wind speed retrieval and fuses the results with random and resampled training samples to balance retrieval accuracies. Compared to the conventional method, the improved method shows reduced RMSE and enhanced correlation coefficient for wind speed retrieval.
SATELLITE NAVIGATION
(2023)
Article
Engineering, Aerospace
Wenyu Feng, Mingying Huo, Ye Xu, Lidong Mo, Weiqin Ke, Yisen Ma, Huanli Su, Naiming Qi
Summary: This paper investigates the methods of online gravity field modeling and trajectory optimization for asteroid soft-landing missions. By using a transfer learning deep neural network and the Bezier shape approach, the study achieves fast online reconstruction and optimization with limited gravity data, significantly improving the accuracy of soft-landing.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Aerospace
Feng Qu, Tianyu Wang, Chaoyu Liu, Junjie Fu, Junqiang Bai
Summary: The aerodynamic performance of the wide-speed-range vortex-shock integrated waverider is improved by introducing the vortex effect and optimizing the aerodynamic shape. The optimized configuration increases the lift and lift-to-drag ratio at subsonic speeds, while increasing the hypersonic lift-to-drag ratio. The analysis of vortex dynamic characteristics shows that the improvement in performance is mainly attributed to the frequency reduction and increased pressure difference.
AEROSPACE SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Aerospace
Ifechukwu Ugochukwu Nzelibe, Herbert Tata, Timothy Oluwadare Idowu
Summary: The study evaluates the potential of using the European Centre for Medium-range Weather Forecast (ECMWF) Reanalysis 5 (ERA5) atmospheric variables for estimating the Zenith Tropospheric Delay (ZTD) in Global Navigation Satellite System (GNSS) positioning. It compares the accuracy of ZTD estimates derived from ERA5 and Global Pressure and Temperature 3 (GPT3) atmospheric variables. The results suggest that ERA5 data can improve the accuracy of ZTD estimation in GNSS positioning.
SATELLITE NAVIGATION
(2023)
Article
Engineering, Aerospace
Wenhao Zhang, Jinling Wang
Summary: Integrity monitoring is critical for precise point positioning in high-accuracy autonomous navigation. However, there are difficulties in the integrity monitoring method for multi-frequency multi-GNSS undifferenced and uncombined Precise Point Positioning (PPP). This study discusses the feasibility of the pseudorange-based baseline ARAIM method on single-epoch PPP based on RTK networks (PPP-RTK) to overcome these difficulties. The simulation results and real kinematic data analysis show that tight Protection Levels (PLs) can be achieved in good observation conditions.
SATELLITE NAVIGATION
(2023)
Article
Engineering, Aerospace
Ju Hong, Rui Tu, Pengfei Zhang, Rui Zhang, Junqiang Han, Lihong Fan, Siyao Wang, Xiaochun Lu
Summary: Simulations were conducted to evaluate the impact of Low Earth Orbit (LEO) satellites on Precise Point Positioning (PPP) convergence. Adding LEO satellites improved satellite geometric distributions and resulted in faster convergence speeds for GPS, BDS, G/C/E/G/R systems. The introduction of LEO observations also improved the success fix rate and Time-To-First-Fix (TTFF) in PPP-AR and PPP-RTK, as well as enhancing positioning performance in different scales of reference networks.
SATELLITE NAVIGATION
(2023)
Article
Engineering, Aerospace
Yongjie Ren, Kangkang Guo, Songjiang Feng, Yiheng Tong, Wei Lin, Wansheng Nie
Summary: This paper investigates transverse combustion instabilities in a multi-injector rocket combustor using n-C12H26 and O2 as fuels, through experimental and numerical analysis. The study captures the instabilities during experiments and analyzes the dynamic characteristics and driving mechanisms through numerical simulation. The findings provide insights into transverse combustion instabilities encountered by rocket engines.
Article
Engineering, Aerospace
D. Fontanarosa, M. A. Signore, A. M. Toscano, M. G. De Giorgi, E. Pescini, A. Ficarella, L. Francioso
Summary: This study provides an experimental investigation of a novel surface dielectric barrier discharge plasma actuator. The results show that the plasma discharge characteristics vary under different pressure conditions, and the discharge range and effect can be controlled by adjusting electrode size and pressure.
Article
Engineering, Aerospace
William P. Schonberg, Michael D. Squire
Summary: In this paper, a single ballistic limit equation for multi-shock shields is developed, which is applicable to various materials and impact velocities, and can be used for selecting and optimizing spacecraft designs in the future.
Article
Engineering, Aerospace
Zhongkai Zhang, Guangchuan Zhang, Renfan Mao, Jiayun Qi, Zun Zhang, Yibai Wang, Junxue Ren, Haibin Tang
Summary: A combined method is proposed to measure the thrust vector and roll torque of low-power Hall-effect thrusters. By changing the position of the accelerator and external hollow cathode, the contributions of the two components of the thruster are analyzed. This method can decrease the deviation angle of the thruster.
Article
Engineering, Aerospace
Carsten Hartmann, Franca Speth, Dieter Sabath, Florian Sellmaier
Summary: Future exploration missions require new concepts of operations to achieve autonomy and independence from ground control. This paper introduces a novel tool based on Columbus operations, allowing for the automatic generation, inspection, approval, and execution of command sequences to enable increased crew autonomy and on-board operations.
Article
Engineering, Aerospace
Zelong Yan, Yang Chen, Youliang Wu, Ziyan Liu, Yushan Gao, Weizong Wang
Summary: This study proposes a systematic and hierarchical multi-physics coupling simulation method to model the combustion and heat transfer phenomena inside the regenerative cooling thrust chamber subsystem of a LOX/methane rocket engine. The method is validated through a verification case and comparisons with steady-state test data, showing its effectiveness and revealing the locations of transition to supercritical state within the cooling channels.
Article
Engineering, Aerospace
Loai Aldaghma, David Muresan, Samuel Renaud
Summary: Space Concordia is launching the largest student-built Canadian rocket to pass the Karman Line, from Churchill, Manitoba. They have established safety protocols and regulations, as well as their own guidelines with the help of the Federal Aviation Administration and local authorities. Using flight simulation software and historical wind data, they have calculated the probability of casualties during the launch and aim to set a structure for future launches.
