Survivability model of LEO satellite constellation based on GERT with limited backup resources

Survivability is used to evaluate the ability of the satellite to complete the mission after failure,while the duration of maintaining performance is often ignored.An effective backup strategy can restore the constellation performance timely,and maintain good network communication performance in case of satellite failure.From the perspective of network utility,the low Earth orbit(LEO)satellite constellation survivable graphical eva-luation and review technology(GERT)network with backup satel-lites is constructed.A network utility transfer function algorithm based on moment generating function and Mason formula is proposed,the network survivability evaluation models of on-orbit backup strategy and ground backup strategy are established.The survivable GERT model can deduce the expected mainte-nance time of LEO satellite constellation under different fault states and the network utility generated during the state mainte-nance period.The case analysis shows that the proposed surviv-able GERT model can consider the satellite failure rate,backup satellite replacement rate,maneuver control replacement ability and life requirement,and effectively determine the optimal sur-vivable backup strategy for LEO satellite constellation with limi-ted resources according to the expected network utility.

Application Advantages of Staring Area Imaging Technology(SAIT) for Microsatellites

The Staring Area Imaging Technology(SAIT) satellite continuously "images" the target over a certain time range, and can realize continuous imaging and multi-angle imaging of the area of interest. It has the characteristics of flexible imaging parameter setting and fast image preprocessing speed, enabling dynamic target detection and tracking, super-resolution, surface 3 D model construction, night-time imaging and many other application tasks. Based on the technical characteristics of the SAIT satellite, this paper analyzes the challenges in satellite development and data processing, focuses on the quasi-realtime application of SAIT satellite data, and looks at the development trend of the SAIT satellite.

Satellite E2E Network Slicing Based on 5G Technology

We investigate the design of satellite network slicing for the first time to provide customized services for the diversified applications,and propose a novel scheme for satellite end-to-end(E2E) network slicing based on 5G technology,which provides a view of common satellite network slicing and supports flexible network deployment between the satellite and the ground.Specifically,considering the limited satellite network resource and the characteristics of the satellite channel,we propose a novel satellite E2E network slicing architecture.Therein,the deployment of the network functions between the satellite and the ground is coordinately considered.Subsequently,the classification and the isolation technologies of satellite network sub-slices are proposed adaptively based on 5G technology to support resource allocation on demand.Then,we develop the management technologies for the satellite E2E network slicing including slicing key performance indicator(KPI) design,slicing deployment,and slicing management.Finally,the analysis of the challenges and future work shows the potential research in the future.

THE APPLICATION OF SATELLITE POSITIONING TECHNOLOGY AND ITS INDUSTRIALIZATION IN CHINA

Satellite positioning technology has been widely used in all kinds of military and civil land, marine, space and aeronautical target positioning tasks, naviga tion activities and accurate surveying measurements since 90 s in the last cen tury due to its advantage in providing all-weather, real-time, three dimensional and high precision positioning information, as well as speed and accurate timing information. By now, it has already formed a new hi-tech industry basically.This paper briefly reviews the development of the global satellite positioning and navigation technologies including the basic information of China's "Plough navigation system", introduces the history of satellite positioning technology and its major application fields as well as the status quo of this being industri alized trade in China, gives an account of the writers' vision for the application and prospect of the satellite positioning technologies in China, and approaches the tactics and stresses of the satellite positioning technology's application and its industrialization future in China.

The Planned Conservation of the Urban Fortifications of Tuscany: Satellite Interferometry as an Innovative Monitoring Technology for Asset Management

The “Monitoring City Walls” research project by the University of Pisa approaches planned conservation as a process that pursues an in-depth understanding of historic city walls and their surroundings to define a system of effective risk prevention. This multidisciplinary research adopts monitoring strategies and technologies at the large scale and in relationship to natural and urban conditions. The underlying logic frames the conservation of these historic fortifications within the more general mitigation of risks generated by context. The research aims to develop an innovative approach to monitoring ancient defensive structures in historical towns. The integrated use of advanced technologies allows for the control and, most importantly, advance identification of possible risks. These new technologies, in particular satellite interferometry, make it possible to improve and increase the operational capacity of monitoring processes by facilitating the acquisition and investigation of data relative to the system defined by ancient city walls and their surroundings. These technologies also represent a cost-effective tool for managing the important transition from the observation and study of individual monuments to the monitoring of large monumental complexes or even entire historical centers.

LM-3B Successfully Launched Communications Technology Test Satellite 2

At 23:18 Beijing time on January 5,a LM-3B carrier rocket lifted off from the Xichang Satellite Launch Center,sending a communication technology test satellite into its preset orbit.This successful launch was a good start for China’s launch missions in 2017.The Communications Technology Test Satellite 2 was developed by the Shanghai Academy of Spaceflight Technology.It is a next-generation telecom-

SJ-9A/B Satellites Conduct Key Technology Tests

On October 14, two satellites SJ-9A/B were sent into their preset orbits by a LM-2C/SMA launch vehicle, which is the first flight of a series of China's civilian technology experimental satellites. SJ-9A and B are the first two satellites in the series of civilian technology experimental satellites designed for tests such as long lifetime and high reliability, high precision and high performance of satellite, domestically developed core components, satellite formation

Applications of Satellite Remote Sensing Technology in China's Environmental Monitoring

The environmental conditions in China are still very serious. In the years to come, the mission for environmental treatment and protection, supervision,

Predictive control for satellite formation keeping

Based on a Hill equation and a nonlinear equation describing the desired and real dynamics of relative motion separately, a predictive controller is brought forward, which makes the real state track the desired ones to keep satellite formation. The stability and robustness of the controller are analyzed. Finally, comparing the simulation results of the proposed controller with that of the traditional, proportional-differential controller shows that the former one is capable of keeping the satellite formation more favorably, considering the disturbances such as the J2 perturbations.

An operational satellite remote sensing system for ocean fishery

Ocean environmental information is very important to supporting the fishermen in fishing and satellite remote sensing technology can provide it in large scale and in near real-time. Ocean fishery locations are always far away beyond the coverage of the satellite data received by a land-based satellite receiving station. A nice idea is to install the satellite ground station on a fishing boat. When the boat moves to a fishery location, the station can receive the satellite data to cover the fishery areas. One satellite remote sensing system was once installed in a fishing boat and served fishing in the North Pacific fishery areas when the boat stayed there. The system can provide some oceanic environmental charts such as sea surface temperature (SST) and relevant derived products which are in most popular use in fishery industry. The accuracy of SST is the most important and affects the performance of the operational system, which is found to be dissatisfactory. Many factors affect the accuracy of SST and it is difficult to increase the accuracy by SST retrieval algorithms and clouds detection technology. A new technology of temperature error control is developed to detect the abnormity of satellite-measured SST. The performance of the technology is evaluated to change the temperature bias from -3.04 to 0.05 ℃ and the root mean square (RMS) from 5.71 to 1.75℃. It is suitable for employing in an operational satellite-measured SST system and improves the performance of the system in fishery applications. The system has been running for 3 a and proved to be very useful in fishing. It can help to locate the candidates of the fishery areas and monitor the typhoon which is very dangerous to the safety of fishing boats.

Satellite SAR observation of shallow bottom topography of the east Australia Sea

A preliminary account of synthetic aperture radar (SAR) imaging mechanisms of oceanic bottom topographic features and a description of the principles of the information extracted from SAR images and the processing and the analysis technology of SAR images are made. Some results were obtained from researching shallow topography and its bathymetric features of the regions of offshore in the east Australia Sea by ERS-1 SAR images. The preliminary research indicates that these features covered with SAR have never been reported before and some results of them are yielded for the first time in Australia. This information is very valuable in a great number of applications to oceanic engineering, shipping navigation, marine fishery and environment, as well as oceanographic research and development. The paper comes to the conclusion that SAR remote sensing of oceanography and its applications are of great potential.

Progress of the satellite laser ranging system TROS1000

The mobile satellite laser ranging system TROS1000, successfully developed in 2010, achieves a high repetition rate and enables daytime laser ranging. Its measurement range has reached up to 36000 km with an accuracy as precise as 1 cm. Using recent observations in Wuhan, Jiufeng, Xianning, and Rongcheng, Shandong, we introduce the progress made using this mobile observation system.

Energetic electron detection packages on board Chinese navigation satellites in MEO

Energetic electron measurements and spacecraft charging are of great significance for theoretical research in space physics and space weather applications.In this paper,the energetic electron detection package(EEDP)deployed on three Chinese navigation satellites in medium Earth orbit(MEO)is reviewed.The instrument was developed by the space science payload team led by Peking University.The EEDP includes a pinhole medium-energy electron spectrometer(MES),a high-energy electron detector(HED)based onΔE-E telescope technology,and a deep dielectric charging monitor(DDCM).The MES measures the energy spectra of 50−600 keV electrons from nine directions with a 180°×30°field of view(FOV).The HED measures the energy spectrum of 0.5−3.0 MeV electrons from one direction with a 30°cone-angle FOV.The ground test and calibration results indicate that these three sensors exhibit excellent performance.Preliminary observations show that the electron spectra measured by the MES and HED are in good agreement with the results from the magnetic electron-ion spectrometer(MagEIS)of the Van Allen Probes spacecraft,with an average relative deviation of 27.3%for the energy spectra.The charging currents and voltages measured by the DDCM during storms are consistent with the highenergy electron observations of the HED,demonstrating the effectiveness of the DDCM.The observations of the EEDP on board the three MEO satellites can provide important support for theoretical research on the radiation belts and the applications related to space weather.

Study on Multi-Rotary Joints Space Power Satellite Concept

The Space Power Satellite(SPS) would be a huge spacecraft capturing the power of solar radiation in space and to supply electric power to the electric grid on the ground. The SPS concept was proposed by Dr. Peter Glaser in 1968. SPS have been studied now for exactly fifty years by many scientists in various countries. It has been regarded as one of the most promising energy projects of the future and has been attracting more attention in recent years. More and more Chinese scholars and experts are paying attention to the development of SPS. Due to the huge size, immense mass and high power of such a satellite system, there are many technical difficulties which exist to realize SPS. In this paper, recent SPS research and development activities are reviewed first. Various SPS concepts are analyzed and compared. The primary scheme of the Multi-Rotary joint SPS(MR-SPS) is described. The main feature is that the huge solar array comprising many separate small solar sub-arrays and each solar sub-array has two middle power rotary joints. So, the most challenging technology, the high-power rotary joint, is simplified by using many middlepower rotary joints hence the possibility of a single-point failure of a single rotary joint is avoided. This enables easy assembly of the modular solar arrays. Finally some key technologies of MR-SPS are analyzed.

Chinese Telemetry Technology under Fast Development

The history of the development of Chinese telemetry is introduced in the paper. The new telemetry ground station and the new onboard space telemetry system, with the idea of systematic design and the specification, are described.

Space Technology for Decarbonising City Precincts

Space technology is a powerful tool for climate research. Satellite data improve knowledge of the human impact on the Planet’s physical geography. Similarly, remote sensing technology enhances understanding of the human impact on rising global carbon emissions. However, so far satellites have been principally limited to measuring the carbon emissions of cities from space. Standing alone, satellite technology is incapable of advancing the goal of decarbonisation. This will be achieved only if cities create local methodologies that significantly enhance the carbon reduction process. There exists enormous potential to bridge remote sensing for earth observation and global environmental change with local action towards decarbonised urban renewal and redevelopment. Satellite remote sensing has the ability to demonstrate if local remedial strategies are succeeding, and assist with planning, developing, and monitoring low and zero carbon infrastructure systems. Satellite-derived data can facilitate informed discussion and decision-making between community stakeholders to deliver low carbon outcomes at the precinct scale. Satellite-based systems can be integrated within the urban fabric to assist climate change mitigation. This paper is based on current work implemented jointly with municipalities to ascertain where within city precincts carbon emissions originate and how they can ultimately be reduced. It presents space technology as an instrumental tool for understanding the carbon impact of cities—in terms of the carbon intensive patterns and processes that shape human society, as well as having great potential for providing end-user products to communities to enhance the process of decarbonising city precincts.

GV Technology for Exploration and Delineation of Lode Gold Claims

Demands for new gold deposits are increasing worldwide and the need to better define lode and placer claims is a critical environmental and economic issue. Recently, interesting results have been produced using dedicated geological information systems designed to explore for earth mineral deposits. These systems employ properties of fundamental physical fields generated by interactions of superlight elementary particles. GV technology （Geo-Vision geological direct detection radiometric and Air-Gamma technology）, a revolutionary technology for exploring the earth from outer space and from inside aircraft, has been utilized to identify and precisely locate gold deposits. All elements of the Earth＇s crust exist in an excited state and are constantly emitting what can be called their ＂intrinsic radiation＂. The melding of science and data interpretation makes GV Technology ideal for defining both lode and placer gold deposits. The use of GV technology will improve success ratios associated with the exploration for and delineation of gold deposits and provide better definition of successful core drilling locations. The technology will also decrease the cost of defining gold deposits and since GV technology is ecologically friendly, it provides considerable reductions in environmental mitigation costs. From 1995 to 2014, GV technology has been used to identify and delineate gold deposits in Russia, Mongolia, Kirghizia, Tanzania, Ethiopia, Namibia, Australia, and the United States.

Distributed Control Technology for Air and Missile Defence Operations

This paper relates to accepted presentation at international conference Air and Missile Defence Technology,November 16-17,2022,London UK(day two),reflecting contents of the presentation slides.It describes applications of the patented and internationally tested Spatial Grasp Technology(SGT)and its Spatial Grasp Language(SGL)for Integrated Air and Missile Defense(IAMD).Based on holistic space navigation and processing by recursive mobile code self-spreading in distributed words,SGT differs radically from traditional management of large systems as consisting of parts exchanging messages.The dynamic network of SGL interpreters can be arbitrarily large and cover terrestrial and celestial environments as powerful spatial engines.The paper contains an example of tracking and destruction of multiple cruise missiles by self-evolving spatial intelligence in SGL using networks of radar stations.It also briefs the growing multiple satellite constellation in Low Earth Orbits(LEO)for potential IAMD applications.Starting from Strategic Defense Initiative(SDI)of the past and then briefing the latest project of Space Development Agency,the paper shows SGL solutions for discovery,tracking,and destroying ballistic missiles and hypersonic gliders with the use of collectively behaving constellations of LEO satellites.It also shows how to organize higher levels of supervision of groups of mobile chasers fighting multiple targets(both potentially as missiles or drones),by providing their global awareness even consciousness in SGL which can drastically improve their performance.The latest version of SGT can be implemented on any platforms and put into operation in a short time,similarly to its previous versions in different countries.

基于分层多智能体的多星联合任务规划架构研究

随着卫星规模、种类的不断增长,现有卫星任务规划技术架构已很难满足多类型卫星联合运用的有效性及可扩展性要求。通过深入分析多星任务筹划、单星任务规划、数传资源规划等环节,建立了基于分层多智能体的多星联合任务规划技术架构,设计了与架构匹配的相关优化算法及智能体功能实现机制,实现了多星联合任务规划能力。仿真实验及分析结果表明,该架构对多类型卫星联合任务规划场景有良好的适用性。

全球卫星互联网关键技术竞争态势与启示

当前,全球正围绕卫星互联网系统建设开展新一轮太空竞赛,其中低轨卫星通信是继卫星导航之后,世界强国在天基信息系统领域的下一个争夺焦点。研究卫星互联网关键技术在推动卫星和通信技术进步、应对全球挑战、引领未来发展等方面具有重大意义。本文通过构建卫星互联网关键技术体系,检索专利数据,从技术发展趋势、技术竞争主体、技术竞争区域和技术竞争领域等维度综合分析卫星互联网关键技术竞争态势。研究发现,我国卫星互联网发展存在起步较晚、关键技术缺失、产业集群不强、场景应用不足等问题。对此提出发展对策:提前布局未来技术,抢占新兴前沿领域;组建创新联合体,加强关键核心技术攻关;强化产学研深度融合,构建产业生态集群;突出通导遥交叉融合,打造多元化应用场景。