Darshan Kumar Jayaram, Vijayanandh Raja, Beena Stanislaus Arputharaj, Hussein A. Z. AL-bonsrulah
Farming and agriculture are the oldest professions, but they are adapting to the technology revolution to accommodate the world’s growing population. UAV technology is part of the agriculture revolution, which aims to boost crop yields, properly monitor fields, and handle manpower shortages and resource efficiency. Rural India’s tiny farmers cannot afford UAV technology; therefore, it has not yet spread. Payload capacity, endurance, and selective spraying are other considerations. Thus, a low-cost, long-lasting UAV is necessary. This study modified the arm assembly to create a cheap hexacopter UAV. The endurance increased by 10% when 1.5 kg was lost. ABS plastic was used to make the modular arm. For working loads of 9 kg and 10 kg, pesticide/fertilizer spraying saves time, money, and manpower. Thus, a pressure-area coverage-cone angle connection is needed. This study examined spray patterns at different pressures and heights by varying flat fan nozzle and complete cone nozzle orifice diameters. These factors were linked, helping farmers choose the right nozzle. This nozzle was installed in the UAV and field-tested for paddy crops, showing a significant production improvement and lower operational cost. Chemical use pollutes and leaves traces in produce. Precision farming with artificial intelligence (AI) has solved this problem. In this experiment, AI algorithms were used to lemon leaves. Three AI systems were tested on different datasets to forecast plant stress by analyzing leaves due to technical constraints. CNN’s accuracy and computing speed make it ideal for precision farming. This work’s UAV was 30% cheaper than commercial UAVs and had more durability. Farmers will also benefit from the flat fan and complete cone nozzles’ pressure-area coverage connection.
{"title":"Design, Multiperspective Investigations, and Performance Analysis of Multirotor Unmanned Aerial Vehicle for Precision Farming","authors":"Darshan Kumar Jayaram, Vijayanandh Raja, Beena Stanislaus Arputharaj, Hussein A. Z. AL-bonsrulah","doi":"10.1155/2024/8703004","DOIUrl":"https://doi.org/10.1155/2024/8703004","url":null,"abstract":"Farming and agriculture are the oldest professions, but they are adapting to the technology revolution to accommodate the world’s growing population. UAV technology is part of the agriculture revolution, which aims to boost crop yields, properly monitor fields, and handle manpower shortages and resource efficiency. Rural India’s tiny farmers cannot afford UAV technology; therefore, it has not yet spread. Payload capacity, endurance, and selective spraying are other considerations. Thus, a low-cost, long-lasting UAV is necessary. This study modified the arm assembly to create a cheap hexacopter UAV. The endurance increased by 10% when 1.5 kg was lost. ABS plastic was used to make the modular arm. For working loads of 9 kg and 10 kg, pesticide/fertilizer spraying saves time, money, and manpower. Thus, a pressure-area coverage-cone angle connection is needed. This study examined spray patterns at different pressures and heights by varying flat fan nozzle and complete cone nozzle orifice diameters. These factors were linked, helping farmers choose the right nozzle. This nozzle was installed in the UAV and field-tested for paddy crops, showing a significant production improvement and lower operational cost. Chemical use pollutes and leaves traces in produce. Precision farming with artificial intelligence (AI) has solved this problem. In this experiment, AI algorithms were used to lemon leaves. Three AI systems were tested on different datasets to forecast plant stress by analyzing leaves due to technical constraints. CNN’s accuracy and computing speed make it ideal for precision farming. This work’s UAV was 30% cheaper than commercial UAVs and had more durability. Farmers will also benefit from the flat fan and complete cone nozzles’ pressure-area coverage connection.","PeriodicalId":13748,"journal":{"name":"International Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139954763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ejector mode of the Rocket-Based Combined-Cycle (RBCC) engine is characterized by high fuel consumption. This study is aimed at investigating the influence of the rocket fuel-rich degree on the RBCC engine’s performance under the ejector mode combined with simultaneous mixing and combustion (SMC). Numerical simulations were conducted for various rocket mixing ratios () under subsonic () and supersonic (
{"title":"Numerical Investigation on the Effect of Fuel-Rich Degree in the RBCC Engine under the Ejector Mode","authors":"Yizhi Yao, Mingbo Sun, Menglei Li, Peibo Li, An Bin, Rui Gu, Jiaoru Wang, Feng Wei, Taiyu Wang, Jikai Chen","doi":"10.1155/2024/4340688","DOIUrl":"https://doi.org/10.1155/2024/4340688","url":null,"abstract":"The ejector mode of the Rocket-Based Combined-Cycle (RBCC) engine is characterized by high fuel consumption. This study is aimed at investigating the influence of the rocket fuel-rich degree on the RBCC engine’s performance under the ejector mode combined with simultaneous mixing and combustion (SMC). Numerical simulations were conducted for various rocket mixing ratios (<span><svg height=\"8.8423pt\" style=\"vertical-align:-0.2064009pt\" version=\"1.1\" viewbox=\"-0.0498162 -8.6359 21.065 8.8423\" width=\"21.065pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,0,0)\"></path></g><g transform=\"matrix(.013,0,0,-0.013,13.434,0)\"></path></g></svg><span></span><svg height=\"8.8423pt\" style=\"vertical-align:-0.2064009pt\" version=\"1.1\" viewbox=\"24.6471838 -8.6359 26.707 8.8423\" width=\"26.707pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,24.697,0)\"></path></g><g transform=\"matrix(.013,0,0,-0.013,30.937,0)\"></path></g><g transform=\"matrix(.013,0,0,-0.013,33.901,0)\"></path></g><g transform=\"matrix(.013,0,0,-0.013,43.773,0)\"></path></g></svg><span></span><span><svg height=\"8.8423pt\" style=\"vertical-align:-0.2064009pt\" version=\"1.1\" viewbox=\"54.9861838 -8.6359 15.753 8.8423\" width=\"15.753pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,55.036,0)\"></path></g><g transform=\"matrix(.013,0,0,-0.013,61.276,0)\"><use xlink:href=\"#g113-47\"></use></g><g transform=\"matrix(.013,0,0,-0.013,64.24,0)\"></path></g></svg>)</span></span> under subsonic (<span><svg height=\"11.8174pt\" style=\"vertical-align:-3.1815pt\" version=\"1.1\" viewbox=\"-0.0498162 -8.6359 32.873 11.8174\" width=\"32.873pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,0,0)\"></path></g><g transform=\"matrix(.013,0,0,-0.013,12.416,0)\"></path></g><g transform=\"matrix(.0091,0,0,-0.0091,18.409,3.132)\"></path></g><g transform=\"matrix(.013,0,0,-0.013,25.242,0)\"><use xlink:href=\"#g117-34\"></use></g></svg><span></span><span><svg height=\"11.8174pt\" style=\"vertical-align:-3.1815pt\" version=\"1.1\" viewbox=\"36.4551838 -8.6359 15.699 11.8174\" width=\"15.699pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,36.505,0)\"></path></g><g transform=\"matrix(.013,0,0,-0.013,42.745,0)\"><use xlink:href=\"#g113-47\"></use></g><g transform=\"matrix(.013,0,0,-0.013,45.709,0)\"></path></g></svg>)</span></span> and supersonic (<span><svg height=\"11.8174pt\" style=\"vertical-align:-3.1815pt\" version=\"1.1\" viewbox=\"-0.0498162 -8.6359 32.873 11.8174\" width=\"32.873pt\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\"><g transform=\"matrix(.013,0,0,-0.013,0,0)\"><use xlink:href=\"#g113-78\"></use></g><g transform=\"matrix(.013,0,0,-0.013,12.416,0)\"><use xlink:href=\"#g113-98\"></use></g><g transform=\"matr","PeriodicalId":13748,"journal":{"name":"International Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139757904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Haidong Shen, Jiwei Du, Kun Yan, Yanbin Liu, Jinbao Chen
Based on the variable gain extended state observer, a finite-time fault-tolerant control strategy is developed for the quadrotor unmanned aerial vehicle with actuator faults and external disturbances. Firstly, a novel variable gain extended state observer is designed to estimate the unknown external disturbances, which mitigates the initial peaking phenomenon existing in traditional extended state observer-based methods. Meanwhile, the neural networks are applied to accurately approximate unknown couplings online. Moreover, with the help of the projection operator technique, the unknown actuator faults are observed in real time. Combined with the backstepping framework, the finite-time robust fault-tolerant control scheme is constructed and the stability is strictly proved via Lyapunov’s theory. Finally, the validity of the developed control scheme is demonstrated through numerical simulations.
{"title":"VGESO-Based Finite-Time Fault-Tolerant Tracking Control for Quadrotor Unmanned Aerial Vehicle","authors":"Haidong Shen, Jiwei Du, Kun Yan, Yanbin Liu, Jinbao Chen","doi":"10.1155/2024/2541698","DOIUrl":"https://doi.org/10.1155/2024/2541698","url":null,"abstract":"Based on the variable gain extended state observer, a finite-time fault-tolerant control strategy is developed for the quadrotor unmanned aerial vehicle with actuator faults and external disturbances. Firstly, a novel variable gain extended state observer is designed to estimate the unknown external disturbances, which mitigates the initial peaking phenomenon existing in traditional extended state observer-based methods. Meanwhile, the neural networks are applied to accurately approximate unknown couplings online. Moreover, with the help of the projection operator technique, the unknown actuator faults are observed in real time. Combined with the backstepping framework, the finite-time robust fault-tolerant control scheme is constructed and the stability is strictly proved via Lyapunov’s theory. Finally, the validity of the developed control scheme is demonstrated through numerical simulations.","PeriodicalId":13748,"journal":{"name":"International Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139667440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Aircraft engine icing caused by supercooled large droplets (SLD) poses a significant threat to flight safety. In this paper, the SLD impingement characteristics of the rotating spinner were investigated using FLUENT UDS and the governing equations for water droplet motion were solved based on the Eulerian method. The droplet breakup was simulated using the number density equation, while the droplet rebound and splashing were simulated using a semiempirical model. The effects of rotational speed, droplet diameter, and inflow velocity on the SLD impingement characteristics of the rotating spinner were studied. Some new valuable insights have been found for the SLD impingement. The results indicated that as the rotational speed increases, the local collection efficiency of the rotating spinner decreases. Higher rotational speed results in reduced droplet impingement angle and stronger droplet rebound and splashing. For the droplets with diameters smaller than 111 μm, the local collection efficiency increases with the increase of the droplet diameter. However, when the droplet diameter exceeds 111 μm, the local collection efficiency decreases near the leading edge of the rotating spinner. Additionally, the local collection efficiency decreases as the inflow velocity increases near the leading edge of the rotating spinner. However, higher inflow velocities lead to larger droplet impingement angles, resulting in higher local collection efficiency near the tail of the rotating spinner. The critical impingement angle increases with the increase of the inflow velocity, leading to a more pronounced rebound and splashing of SLD. The research in this paper provides useful help for ice shape prediction and anti-icing system design of rotating spinner in SLD environment.
{"title":"Numerical Investigation of Supercooled Large Droplets Impingement Characteristics of the Rotating Spinner","authors":"Wei Jia, Feng Zhang","doi":"10.1155/2024/1683744","DOIUrl":"https://doi.org/10.1155/2024/1683744","url":null,"abstract":"Aircraft engine icing caused by supercooled large droplets (SLD) poses a significant threat to flight safety. In this paper, the SLD impingement characteristics of the rotating spinner were investigated using FLUENT UDS and the governing equations for water droplet motion were solved based on the Eulerian method. The droplet breakup was simulated using the number density equation, while the droplet rebound and splashing were simulated using a semiempirical model. The effects of rotational speed, droplet diameter, and inflow velocity on the SLD impingement characteristics of the rotating spinner were studied. Some new valuable insights have been found for the SLD impingement. The results indicated that as the rotational speed increases, the local collection efficiency of the rotating spinner decreases. Higher rotational speed results in reduced droplet impingement angle and stronger droplet rebound and splashing. For the droplets with diameters smaller than 111 <i>μ</i>m, the local collection efficiency increases with the increase of the droplet diameter. However, when the droplet diameter exceeds 111 <i>μ</i>m, the local collection efficiency decreases near the leading edge of the rotating spinner. Additionally, the local collection efficiency decreases as the inflow velocity increases near the leading edge of the rotating spinner. However, higher inflow velocities lead to larger droplet impingement angles, resulting in higher local collection efficiency near the tail of the rotating spinner. The critical impingement angle increases with the increase of the inflow velocity, leading to a more pronounced rebound and splashing of SLD. The research in this paper provides useful help for ice shape prediction and anti-icing system design of rotating spinner in SLD environment.","PeriodicalId":13748,"journal":{"name":"International Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139667472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thunderstorms are recognized as perilous meteorological phenomena characterized by irregular and nonlinear movement, posing significant risks to approaching aircraft and necessitating technical methods to ensure safety to the aviation operations. This research specifically addresses the challenges associated with aircraft during the approach segment and introduces a multialgorithmic model focusing on the optimization of 4D approach trajectory. Firstly, the artificial neural network intelligent model was used to predict the thunderstorm movement track. Secondly, the multialgorithmic model combined by the rapidly exploring random tree with artificial potential field was built to plan the trajectory of the approaching aircraft under thunderstorm weather, and then, the mean filter was adopted to smooth the simulated approaching trajectory. Finally, the reliability of the model with a real case study was demonstrated. After optimized simulation by predicting the thunderstorm weather and trajectory-optimized multialgorithmic model mentioned above, the approach trajectory can be outputted successfully, but with some distortions, postprocessing with the mean filter results in a remarkably smooth approach trajectory, providing enhanced feasibility and efficiency for pilots navigating through thunderstorm weather conditions. It is ultimately proved that refined 4D trajectory operations under hazardous weather conditions hold substantial significance in advancing aviation safety and operational effectiveness.
{"title":"Model of Multi-Algorithmic-Based Optimization of 4D Approach Trajectory under Thunderstorm Weather","authors":"Li Lu, Xin Lai","doi":"10.1155/2024/1614684","DOIUrl":"https://doi.org/10.1155/2024/1614684","url":null,"abstract":"Thunderstorms are recognized as perilous meteorological phenomena characterized by irregular and nonlinear movement, posing significant risks to approaching aircraft and necessitating technical methods to ensure safety to the aviation operations. This research specifically addresses the challenges associated with aircraft during the approach segment and introduces a multialgorithmic model focusing on the optimization of 4D approach trajectory. Firstly, the artificial neural network intelligent model was used to predict the thunderstorm movement track. Secondly, the multialgorithmic model combined by the rapidly exploring random tree with artificial potential field was built to plan the trajectory of the approaching aircraft under thunderstorm weather, and then, the mean filter was adopted to smooth the simulated approaching trajectory. Finally, the reliability of the model with a real case study was demonstrated. After optimized simulation by predicting the thunderstorm weather and trajectory-optimized multialgorithmic model mentioned above, the approach trajectory can be outputted successfully, but with some distortions, postprocessing with the mean filter results in a remarkably smooth approach trajectory, providing enhanced feasibility and efficiency for pilots navigating through thunderstorm weather conditions. It is ultimately proved that refined 4D trajectory operations under hazardous weather conditions hold substantial significance in advancing aviation safety and operational effectiveness.","PeriodicalId":13748,"journal":{"name":"International Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139645456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Most human-caused flight accidents can be attributed to a pilot’s attention deficit and monitoring errors. Accordingly, pilots’ attention allocation is strongly related to their task performance. This study is aimed at analyzing pilots’ fixation characteristics and attention-allocation levels. First, we proposed a model for measuring attention-allocation level based on the salience, effort, expectancy, and value (SEEV) model. Second, a low-fidelity single-pilot operation (SPO) cockpit environment was constructed, and 20 pilots were recruited for an experiment to compare their fixation characteristics between SPO and double-pilot operation (DPO) scenarios. The results showed slight differences in the attention levels allocated by SPO and DPO pilots under a scenario of one-engine failure. It concluded that Human-centered flight deck design can enhance a pilot’s attention allocation level. These findings can be used to optimize future flight deck designing and flight training for improving pilot’s task performance.
{"title":"A Real-Time Measurement Model of Attention-Allocation Level and Its Application in Simulated SPO Task","authors":"Lei Wang, Zhiyang Zhang, Wei Tan, Zhongchang Yang","doi":"10.1155/2024/3901699","DOIUrl":"https://doi.org/10.1155/2024/3901699","url":null,"abstract":"Most human-caused flight accidents can be attributed to a pilot’s attention deficit and monitoring errors. Accordingly, pilots’ attention allocation is strongly related to their task performance. This study is aimed at analyzing pilots’ fixation characteristics and attention-allocation levels. First, we proposed a model for measuring attention-allocation level based on the salience, effort, expectancy, and value (SEEV) model. Second, a low-fidelity single-pilot operation (SPO) cockpit environment was constructed, and 20 pilots were recruited for an experiment to compare their fixation characteristics between SPO and double-pilot operation (DPO) scenarios. The results showed slight differences in the attention levels allocated by SPO and DPO pilots under a scenario of one-engine failure. It concluded that Human-centered flight deck design can enhance a pilot’s attention allocation level. These findings can be used to optimize future flight deck designing and flight training for improving pilot’s task performance.","PeriodicalId":13748,"journal":{"name":"International Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139585251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wen Zou, Zhanxin Cui, Genghui Li, Zhiwei Feng, Zhenkun Wang, Qingyu Gao, Qingbin Zhang, Tao Yang
In the field of aerospace, solving the boundary problem associated with the parachute-capsule system remains a big challenge. The conventional Monte Carlo method proves inadequate for acquiring comprehensive boundary information. To address this issue, this paper introduces a novel tube prediction scheme by leveraging the natural geometric characteristics of the reachable tube and employing a multiobjective optimization strategy. Initially, a multibody dynamic model with nine degrees of freedom was established and verified by the airdrop test data to ensure the accuracy and reliability of the model. Subsequently, the Sobol sensitivity analysis method was employed to assess uncertain factors that affect the deceleration phase of the reentry capsule. These factors are then utilized to determine the optimization parameters for the multiobjective optimization model. Ultimately, the multiobjective evolutionary algorithm based on decomposition was employed to solve the multiobjective optimization model, and the geometric boundary of the tube corresponds to the Pareto front of the multiobjective optimization. The proposed methodology was validated through a simulation experiment utilizing the Chang’e-5 reentry capsule as an engineering case. The experimental results unequivocally demonstrate the superior accuracy of our approach in predicting the boundary of the reachable tube compared to the Monte Carlo method. This research serves as a valuable reference for calculating reachable tubes in practical engineering scenarios and can be effectively applied to spacecraft search and rescue operations during the reentry phase.
{"title":"Reentry Capsule Reachable Tube Boundary Prediction via Evolutionary Multiobjective Optimization","authors":"Wen Zou, Zhanxin Cui, Genghui Li, Zhiwei Feng, Zhenkun Wang, Qingyu Gao, Qingbin Zhang, Tao Yang","doi":"10.1155/2024/2311998","DOIUrl":"https://doi.org/10.1155/2024/2311998","url":null,"abstract":"In the field of aerospace, solving the boundary problem associated with the parachute-capsule system remains a big challenge. The conventional Monte Carlo method proves inadequate for acquiring comprehensive boundary information. To address this issue, this paper introduces a novel tube prediction scheme by leveraging the natural geometric characteristics of the reachable tube and employing a multiobjective optimization strategy. Initially, a multibody dynamic model with nine degrees of freedom was established and verified by the airdrop test data to ensure the accuracy and reliability of the model. Subsequently, the Sobol sensitivity analysis method was employed to assess uncertain factors that affect the deceleration phase of the reentry capsule. These factors are then utilized to determine the optimization parameters for the multiobjective optimization model. Ultimately, the multiobjective evolutionary algorithm based on decomposition was employed to solve the multiobjective optimization model, and the geometric boundary of the tube corresponds to the Pareto front of the multiobjective optimization. The proposed methodology was validated through a simulation experiment utilizing the Chang’e-5 reentry capsule as an engineering case. The experimental results unequivocally demonstrate the superior accuracy of our approach in predicting the boundary of the reachable tube compared to the Monte Carlo method. This research serves as a valuable reference for calculating reachable tubes in practical engineering scenarios and can be effectively applied to spacecraft search and rescue operations during the reentry phase.","PeriodicalId":13748,"journal":{"name":"International Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139585257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Guangkai Liu, Jie Guo, Weizheng Xin, Cheng Cheng, Lu Wang
Aimed at the antijamming needs of the space tracking, telemetry command (TT&C) receiver under a low signal-to-noise ratio, the anti-interference advantage of the dual-sequence frequency hopping (DSFH) communication system is applied. The channel amplitude fading influence of the receiver operating characteristics (ROC) of the TT&C receiver based on the DSFH is studied. Firstly, based on the typical channel model of the Rayleigh fading without direct path transmission, the conditional Fokker-Planck equation (FPE) is obtained by analyzing the statistical independence of the Rayleigh fading signal and SR output particle moments. Secondly, the probability density function (PDF) of the DSFH signal via channel Rayleigh fading enhanced by stochastic resonance (SR) is obtained by introducing the decision time. Thirdly, the detection probability, false alarm probability, ROC, and system bit error rate (BER) of the DSFH signals enhanced by SR under the Rayleigh fading conditions are obtained, under the minimum BER criterion. Finally, the conclusions are reached: one is that the DSFH signals via channel Rayleigh fading can still be detected by the SR system under low SNR, and the other one is that the SNR can reach the -13 dB by the reception of DSFH signal enhanced by SR, when the Rayleigh fading parameter is 0.2042.
针对低信噪比条件下空间跟踪、遥测指令（TT&C）接收机的抗干扰需求，应用了双序列跳频（DSFH）通信系统的抗干扰优势。研究了信道幅度衰落对基于 DSFH 的 TT&C 接收机的接收机工作特性（ROC）的影响。首先，基于典型的无直接路径传输的瑞利衰落信道模型，通过分析瑞利衰落信号和 SR 输出粒子矩的统计独立性，得到条件福克-普朗克方程（FPE）。其次，通过引入决策时间，得到经随机共振（SR）增强的信道瑞利衰落的 DSFH 信号的概率密度函数（PDF）。第三，在最小误码率准则下，得到了瑞利衰落条件下经随机共振增强的 DSFH 信号的检测概率、误报概率、ROC 和系统误码率（BER）。最后得出结论：一是经信道瑞利衰落的 DSFH 信号在低信噪比条件下仍能被 SR 系统检测到；二是当瑞利衰落参数为 0.2042 时，通过 SR 增强的 DSFH 信号接收信噪比可达-13 dB。
{"title":"The Channel Fading Influence of the Receiver Operating Characteristics of the TT&C Receiver Based on the Dual-Sequence Frequency Hopping","authors":"Guangkai Liu, Jie Guo, Weizheng Xin, Cheng Cheng, Lu Wang","doi":"10.1155/2024/1850204","DOIUrl":"https://doi.org/10.1155/2024/1850204","url":null,"abstract":"Aimed at the antijamming needs of the space tracking, telemetry command (TT&C) receiver under a low signal-to-noise ratio, the anti-interference advantage of the dual-sequence frequency hopping (DSFH) communication system is applied. The channel amplitude fading influence of the receiver operating characteristics (ROC) of the TT&C receiver based on the DSFH is studied. Firstly, based on the typical channel model of the Rayleigh fading without direct path transmission, the conditional Fokker-Planck equation (FPE) is obtained by analyzing the statistical independence of the Rayleigh fading signal and SR output particle moments. Secondly, the probability density function (PDF) of the DSFH signal via channel Rayleigh fading enhanced by stochastic resonance (SR) is obtained by introducing the decision time. Thirdly, the detection probability, false alarm probability, ROC, and system bit error rate (BER) of the DSFH signals enhanced by SR under the Rayleigh fading conditions are obtained, under the minimum BER criterion. Finally, the conclusions are reached: one is that the DSFH signals via channel Rayleigh fading can still be detected by the SR system under low SNR, and the other one is that the SNR can reach the -13 dB by the reception of DSFH signal enhanced by SR, when the Rayleigh fading parameter is 0.2042.","PeriodicalId":13748,"journal":{"name":"International Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139585256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The traditional Kalman filter assumes that all measurements can be obtained in real time, which is invalid in practical engineering. Therefore, a variational Bayesian- (VB-) based Gaussian sum cubature Kalman filter is proposed to solve the nonlinear tracking problem of multistep random measurement delay and loss (MRMDL) with unknown probability. First, the measurement model with MRMDL is modified by Bernoulli random variables. Then, the expression of the likelihood function is reformulated as a mixture of multiple Gaussian distributions, and the cubature rule is used to improve the estimation accuracy under the framework of Gaussian sum filter in the process of time update. Finally, by constructing a hierarchical Gaussian model, the unknown and time-varying measurement delay and loss probability are estimated in real time with the state jointly using the VB method in the measurement update stage. The algorithm does not need to calculate the equivalent noise covariance matrix so as to avoid the possible division by zero operation, which improves the stability of the algorithm. Simulation results for a target tracking problem show that the proposed algorithm has a better performance in the presence of MRMDL and can estimate the unknown measurement delay and loss probability accurately.
{"title":"VB-Based Gaussian Sum Cubature Kalman Filter for Adaptive Estimation of Unknown Delay and Loss Probability","authors":"Ruipeng Wang, Xiaogang Wang, Haojie Zhang","doi":"10.1155/2024/5599144","DOIUrl":"https://doi.org/10.1155/2024/5599144","url":null,"abstract":"The traditional Kalman filter assumes that all measurements can be obtained in real time, which is invalid in practical engineering. Therefore, a variational Bayesian- (VB-) based Gaussian sum cubature Kalman filter is proposed to solve the nonlinear tracking problem of multistep random measurement delay and loss (MRMDL) with unknown probability. First, the measurement model with MRMDL is modified by Bernoulli random variables. Then, the expression of the likelihood function is reformulated as a mixture of multiple Gaussian distributions, and the cubature rule is used to improve the estimation accuracy under the framework of Gaussian sum filter in the process of time update. Finally, by constructing a hierarchical Gaussian model, the unknown and time-varying measurement delay and loss probability are estimated in real time with the state jointly using the VB method in the measurement update stage. The algorithm does not need to calculate the equivalent noise covariance matrix so as to avoid the possible division by zero operation, which improves the stability of the algorithm. Simulation results for a target tracking problem show that the proposed algorithm has a better performance in the presence of MRMDL and can estimate the unknown measurement delay and loss probability accurately.","PeriodicalId":13748,"journal":{"name":"International Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139553763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Space close-range inspection can be used to carry out close-range observation and monitoring of targets for identifying the target’s types and working states, which is of great significance for space missions such as in-orbit services. The effectiveness evaluation of space inspection tasks will significantly affect the studies on the trajectory design, orbit motion control, and task termination conditions. However, the evaluation models in previous studies are too simple such as that they are usually without considering dynamic changes in the satellite orbit relative motion. Besides, these studies fail to build a comprehensive evaluation model for the whole inspection task process. In this paper, taking the most commonly used optical inspection as an example, the novel multifactor inspection task effectiveness evaluation models were investigated, including the constraint models of observation, the relative distance evaluation model, the effective observation time evaluation model, and the target observation angle evaluation model. These models solve the effectiveness evaluation problem for the complete process of an inspection task, which can support the design of inspection strategies and trajectories better by using the evaluation results. In addition, numerical simulations and 20 semiphysical experiments were carried out to validate the proposed evaluation models.
{"title":"Investigation and Validation of Mission Evaluation Models for Space Close-Range Inspection","authors":"Jianyong Zhou, Zhipu Hou, Kebo Li","doi":"10.1155/2024/8841710","DOIUrl":"https://doi.org/10.1155/2024/8841710","url":null,"abstract":"Space close-range inspection can be used to carry out close-range observation and monitoring of targets for identifying the target’s types and working states, which is of great significance for space missions such as in-orbit services. The effectiveness evaluation of space inspection tasks will significantly affect the studies on the trajectory design, orbit motion control, and task termination conditions. However, the evaluation models in previous studies are too simple such as that they are usually without considering dynamic changes in the satellite orbit relative motion. Besides, these studies fail to build a comprehensive evaluation model for the whole inspection task process. In this paper, taking the most commonly used optical inspection as an example, the novel multifactor inspection task effectiveness evaluation models were investigated, including the constraint models of observation, the relative distance evaluation model, the effective observation time evaluation model, and the target observation angle evaluation model. These models solve the effectiveness evaluation problem for the complete process of an inspection task, which can support the design of inspection strategies and trajectories better by using the evaluation results. In addition, numerical simulations and 20 semiphysical experiments were carried out to validate the proposed evaluation models.","PeriodicalId":13748,"journal":{"name":"International Journal of Aerospace Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139553581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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