Recent Progress of Earth Observation Satellites in China

Currently,China has 32 Earth observation satellites in orbit.The satellites can provide various data such as optical,multispectral,infrared,and radar.The spatial resolution of China Earth observation satellites ranges from low to medium to high.The satellites possess the capability to observe across multiple spectral bands,under all weather conditions,and at all times.The data of China Earth observation satellites has been widely used in fields such as natural resource detection,environmental monitoring and protection,disaster prevention and reduction,urban planning and mapping,agricultural and forestry surveys,land survey and geological prospecting,and ocean forecasting,achieving huge social benefits.This article introduces the recent progress of Earth observation satellites in China since 2022,especially the satellite operation,data archiving,data distribution and data coverage.

Monitoring Wildfires in Thailand: A Case Study of the ECSTAR-TeroSpace’s Earth Observation Project

The primary objective of this paper is to present a comprehensive case study on monitoring wildfires in Nakhon Nayok, Thailand, utilizing Earth observation platforms. This initiative project has been undertaken by the Excellence Center of Space Technology and Research (ECSTAR), in partnership with its spin-off startup, TeroSpace. The study aims to provide an in-depth analysis of the wildfire incidents in the region, utilizing advanced technologies such as satellite imagery and data analytics, and to identify ways to improve future wildfire management. In particular, the paper focuses on the wildfires including thermal area comparison that ravaged the land in Nakhon Nayok Province in central Thailand from March to April 18th, 2023. To conduct this study, the ECSTAR-TeroSpace analytic team utilized satellite images from Earth observation platforms: MODIS and Sentinel-2A. By presenting this case study, this paper contributes to the broader understanding of how to monitor and manage wildfires in a changing climate. The findings of this study underscore the importance of proactive and collaborative efforts in mitigating the negative impacts of wildfires in Nakhon Nayok and other regions in Thailand.

Improved algorithms to plan missions for agile earth observation satellites

This study concentrates of the new generation of the agile （AEOS）. AEOS is a key study object on management problems earth observation satellite in many countries because of its many advantages over non-agile satellites. Hence, the mission planning and scheduling of AEOS is a popular research problem. This research investigates AEOS characteristics and establishes a mission planning model based on the working principle and constraints of AEOS as per analysis. To solve the scheduling issue of AEOS, several improved algorithms are developed. Simulation results suggest that these algorithms are effective.

Mission Planning and Action Planning for Agile Earth-Observing Satellite with Genetic Algorithm

This paper concerns the mission scheduling problem for an agile Earth-observing satellite. Mission planning and action planning for the satellite are both taking into account. Multiple mission types( including multi-strip area,real time download request,and stereoscopic request) and complex satellite actions,such as observe action and data download action,are considered in this paper. Through reasonable analysis of specialties and operational constraints of agile satellites in observing process,the mission scheduling model under multiple objective conditions is constructed. A genetic algorithm combined with heuristic rules is designed to solve problem. Genetic algorithm is designed to arrange user missions and heuristic rules are used to arrange satellite actions. Experiment results suggest that our algorithm works well for the agile Earth-observing satellite scheduling problem.

Conspiracy Determines World War III with Reference to Several Windows’ Channel in Connection with Earth Observation Satellite

Thermonuclear reaction exerts its influence of X-emission to produce several windows’ channel in the presence of an oscillator under electrical relay circuit with a decisive importance to a radiofrequency Earth observation satellite. Indian Television Network (National Channel) has introduced a radiofrequency accelerator to produce X-emission at resonance with an activation of artificial human environment under relay analogy in the presence of an Earth observation satellite. Thermonuclear reaction communicates several windows’ channel via Earth observation satellite. Star Television network communicates an artificial human environment under the influence of a relay circuit with different pulse code units of human brain with an active influence of an artificial sensation to generate the loss of humanity around the world.

A Fast Insertion Tabu Search with Conflict-Avoidance Heuristic for the Multisatellite Multimode Crosslink Scheduling Problem

An agile earth-observing satellite equipped with multimode cameras capable of transmitting observation data to other satellites is developed to rapidly respond to requests with multiple observation modes.This gives rise to the Multisatellite Multimode Crosslink Scheduling(MMCS)problem,which involves allocating observation requests to agile satellites,selecting appropriate timing and observation modes for the requests,and transmitting the data to the ground station via the satellite communication system.Herein,a mixed integer programming model is introduced to include all complex time and operation constraints.To solve the MMCS problem,a two-stage heuristic method,called Fast insertion Tabu Search with Conflict-avoidance(FTS-C)heuristic,is developed.In the first stage,a conflict-avoidance insertion algorithm is designed to generate a high-quality initial solution by considering the requests transmission and download.Further,the tabu search-based second stage optimizes the initial solution.Finally,an extensive empirical study based on a real-world situation demonstrates that FTS-C can generate a solution with higher quality in less time than other state-of-the-art algorithms and the CPLEX solver.

Distributed cooperative task planning algorithm for multiple satellites in delayed communication environment

Multiple earth observing satellites need to communicate with each other to observe plenty of targets on the Earth together. The factors, such as external interference, result in satellite information interaction delays, which is unable to ensure the integrity and timeliness of the information on decision making for satellites. And the optimization of the planning result is affected. Therefore, the effect of communication delay is considered during the multi-satel ite coordinating process. For this problem, firstly, a distributed cooperative optimization problem for multiple satellites in the delayed communication environment is formulized. Secondly, based on both the analysis of the temporal sequence of tasks in a single satellite and the dynamically decoupled characteristics of the multi-satellite system, the environment information of multi-satellite distributed cooperative optimization is constructed on the basis of the directed acyclic graph（DAG）. Then, both a cooperative optimization decision making framework and a model are built according to the decentralized partial observable Markov decision process（DEC-POMDP）. After that, a satellite coordinating strategy aimed at different conditions of communication delay is mainly analyzed, and a unified processing strategy on communication delay is designed. An approximate cooperative optimization algorithm based on simulated annealing is proposed. Finally, the effectiveness and robustness of the method presented in this paper are verified via the simulation.

General modeling and optimization technique for real-world earth observation satellite scheduling

Over the last two decades,many modeling and optimization techniques have been developed for earth observation satellite(EOS)scheduling problems,but few of them show good generality to be engineered in realworld applications.This study proposes a general modeling and optimization technique for common and real-world EOS scheduling cases;it includes a decoupled framework,a general modeling method,and an easy-to-use algorithm library.In this technique,a framework that decouples the modeling,constraints,and optimization of EOS scheduling problems is built.With this framework,the EOS scheduling problems are appropriately modeled in a general manner,where the executable opportunity,another format of the well-known visible time window per EOS operation,is viewed as a selectable resource to be optimized.On this basis,10 types of optimization algorithms,such as Tabu search and genetic algorithm,and a parallel competitive memetic algorithm,are developed.For simplified EOS scheduling problems,the proposed technique shows better performance in applicability and effectiveness than the state-of-the-art algorithms.In addition,a complicatedly constrained real-world benchmark exampled by a four-EOS Chinese commercial constellation is provided,and the technique is qualified and outperforms the in-use scheduling system by more than 50%.

对地观测卫星姿态控制系统效能评估方法

卫星系统效能评估问题,是卫星提高工作效率和卫星方案优化设计的基础。以对地观测卫星姿态控制系统作为效能评估的对象,通过对卫星的任务需求进行分析,建立对地观测卫星姿态控制系统效能评估指标体系;基于灰色关联分析相关理论,引入熵权法计算指标权重,建立效能评估模型,计算得到综合灰色关联度,实现卫星姿态控制系统效能评估;通过数据验证所建体系具有可实现性与实用性。

海洋一号卫星观测任务规划算法设计及系统应用

针对海洋一号卫星观测任务规划需求,提出并实现了基于遗传策略的任务规划框架,解决了卫星实际使用中成像任务受卫星其他业务影响的多类型约束成像规划问题。基于海洋一号卫星实际规划业务要求,对任务规划约束和优化目标建立数学模型,提出了由预处理、窗口约束处理和组合约束处理与优化组成的三阶段规划框架。设计了多约束任务规划优化目标函数,并利用交叉、变异和种群选择等遗传机制对优化问题进行了求解。基于海洋一号卫星实际观测需求数据,对提出的算法进行了有效性和性能验证,结果表明本算法能够给出满足多类型约束的观测规划方案,并在观测时间、观测覆盖率等方面较其他策略有显著提升。研究结果表明通过优化目标函数的设计遗传算法能够实现复杂约束条件的成像规划求解,算法框架可为与海洋卫星具有相似业务特点的对地观测规划系统设计提供借鉴。

基于特征参数拟合的多地面目标双星星下点轨迹规划

为解决具有多次轨道机动能力、多探测目标、多探测器协同的对地观测任务的星下点轨迹规划优化问题,提出一种基于特征参数拟合的星下点轨迹快速计算方法,并采用基于数据库的星下点轨迹拼接方法建立优化模型。首先,对描述星下点轨迹的特征参数进行分析和提炼,采用多项式对特征参数进行拟合实现快速计算;然后,根据探测目标建立观测码数据库,再进一步整理成轨迹数据库;最后,建立基于轨迹数据库的优化模型,解决整个星下点轨迹规划问题。对第11届全国空间轨道设计竞赛的固定目标快速全覆盖任务进行仿真,能够在19.19 d内完成该任务,表明所提设计方法和方案,可用于各类近圆轨道的星下点轨迹设计。

机载导航设备辅助的LEO卫星定位方法与仿真验证

复杂电磁环境下全球导航卫星系统(GNSS)容易被欺骗和干扰导致不可使用,而近地轨道(LEO)通导一体化卫星系统具有落地功率高和星座几何形状变化快的优势,是一种很好的应急备份导航源。但大多数LEO卫星系统在中低纬度地区可见卫星的数量仅有1~2颗,无法实现实时动态定位。因此,提出一种基于机载惯性导航系统(INS)、气压计辅助的组合定位算法,将INS、气压计当作伪卫星使用,通过配置原子钟联合来解决可观性不足的问题。所提算法利用LEO卫星观测数据修正INS的误差,同时针对可观性不能定量分析的问题提出一种衡量滤波器稳定的可估计性指标。仿真验证表明:所提算法利用LEO观测数据在9 min内将INS误差降低了60%左右,定位误差达到50 m以下,能够实现实时、稳定定位,提出的可估计性指标也能够衡量系统的稳定性。

对地观测卫星编队协同容错姿轨耦合控制

面向对地观测场景下卫星编队的姿轨耦合特性和完全失效故障,提出了基于空间构型重构的协同容错控制方法。首先,根据对地观测的任务需求,分别建立了无故障情况下的卫星编队构型,以及故障发生后将故障卫星移出编队的构型重构方案,包括拓扑网络重构、卫星编号更新和编队构型重构算法;其次,根据上述构型,考虑外部干扰和姿态轨道耦合特性,设计了基于非奇异终端滑模控制的分布式控制律,使得编队在有限时间内稳定,即在故障发生前后卫星编队都可以实现对观测区域的协同覆盖;最后,分别通过数值仿真和实验验证表明了所提方法的有效性。

微纳遥感网对地观测需求筹划与分析方法

微纳遥感网由大量微纳卫星组成,具备高时空覆盖度的对地观测能力,但需求冲突消解的难度亦急剧增加。针对此问题,分析了微纳遥感网对地观测工作模式和约束条件,面向大面积区域目标,提出了一种周期驱动的微纳遥感网对地观测需求筹划方法,并基于真实卫星轨道数据,以四川省为应用实例对筹划结果覆盖性能进行仿真分析。该方法简化了对地观测工作模式,能够实现区域目标的多次重复观测,为微纳遥感网对地观测质量提升奠定数据基础。

基于效能评估的卫星资源调度方法

对地观测卫星作为国家基础性战略资源,在国民经济、社会发展和国家安全等方面发挥着关键作用;一直以来,如何通过调度手段,发挥对地观测卫星资源的应用效能,使其完成更多的观测任务,是航天领域的一个研究热点;通过卫星资源效能评估的方式,对卫星对地观测效能进行事前评估的定量分析,并将效能评估结果应用在对地观测卫星资源调度上,采用一种基于KM算法的卫星资源最优调度方法,实现卫星资源在执行多个对地观测任务过程中的整体效能最大化,可为卫星资源调度、优化建设提供参考和决策支撑。

透视空天红外遥感探测技术:演进规律与发展趋势

空天红外遥感探测技术对国民经济发展和战略国防能力建设具有重要意义,是推动我国红外科技进步的关键引擎,更是实现航天科技强国战略的重要基石。本文重点展现了气象卫星观测技术、地物目标精细成像技术、红外焦平面探测器技术以及新时代背景下的遥感应用等多个与红外科技紧密相连的关键领域的研究进展。通过系统梳理相关技术的发展脉络,总结演进规律,并深入剖析最新研究成果,旨在精准洞察未来空天红外科技的潜在发展方向,为我国红外科技的不断创新和航天事业的蓬勃发展提供坚实的支撑。

Publishing China satellite data on the GEOSS Platform

This paper is the first of a series that describes some of the main dataset resources presently shared through the GEOSS Platform.The GEOSS Platform has been created to provide the technological tool to implement the Global Earth Observation System of Systems(GEOSS);it is a brokering infrastructure that presently brokers more than 190 autonomous data catalogs and information systems.The paper analyses the China Satellite datasets and describes the data publishing process from China GEOSS Data Provider to the GEOSS Platform considering both administrative registration as well as the technical registration.The China Satellite datasets are considered as one of the most important satellite data shared by the GEOSS Platform.The analysis provides some insights as well about GEOSS user searches for China Satellite datasets.

面向应急航天对地观测任务的效能评估方法研究

航天对地观测具有时效高、覆盖广等特点,在应急事件的信息支援中起到了十分重要的作用,因此对地观测卫星任务已由日常性计划转变为实时性响应。文章面向应急观测任务,基于天地及资源使用情况对卫星任务效能进行了分析与归纳。同时,以提高应急任务效能为目标,建立了面向应急观测任务效能的评估体系。其中,首先分析了应急观测任务综合效能评估指标方法与模式,其次抽象评估了对象指标并建立了效能分析评估模型。通过应急航天对地观测任务的效能评估定量评价,可为后续应急观测的应用模式、策略优化、体系优化设计提供有力支撑,从而对航天资源能力建设和发展规划提供依据。

对地观测卫星知识图谱的构建与应用

【目的】为厘清对地观测卫星、平台、仪器、传感器、相关参数之间的关系,为相关数据智能查询和知识推理提供知识基础,提出构建对地观测卫星知识图谱。【方法】本研究通过自顶向下与自底向上相结合的知识图谱构建技术,使用自然语言处理和人工审核的方法进行卫星数据的提取、融合和质量评估,构建对地观测卫星知识图谱。【结果】总结了知识图谱的逻辑架构和技术架构,梳理了对地观测卫星知识图谱的构建流程,最终构建了包含8种实体、9种关系和33种属性的对地观测卫星知识图谱。【结论】凭借对地观测卫星知识图谱结构化视图和智能查询的功能为卫星数据管理提供了新的解决方案,将在未来促进地球科学研究和社会服务中取得更广泛的成果。

星基GNSS掩星事件预报方法分析

针对全球卫星导航系统(GNSS)星基掩星观测时长通常仅有几十秒,特别是在升星掩星观测中,需要快速实现负高度角卫星信号的捕获跟踪,才能获得及时有效的掩星观测时长的问题,基于先验轨道信息辅助的开环跟踪技术,提出一种基于切线高度的掩星事件快速预报方法,以辅助掩星接收机快速捕获和跟踪GNSS掩星信号,从而保证掩星观测数据质量和有效观测时长:对地球局部曲率中心进行修正,得到更为精准的切线高度;然后设置掩星事件的判决条件,采用极值的方式快速预报出符合阈值的掩星事件;最后对全球内曲率中心和曲率半径进行分析。实验结果表明,曲率中心的修正距离最大值可至45 km,曲率半径波动范围可达到65 km,足以影响掩星探测的准确预报。基于气象、电离层和气候星座观测系统(COSMIC-2)实测数据的仿真结果表明,掩星预报的全球定位系统(GPS)掩星漏报率低于3%,格洛纳斯卫星导航系统(GLONASS)掩星漏报率约14.5%,且预报掩星开始时间大多提前5~10 s;证明基于切线高度的掩星预报方法能够有效地应用于星基掩星事件的预报,以辅助接收机准确捕获和跟踪信号,提升掩星观测资料的数据量和有效观测时长。