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'Proceedings of the 26th Conference of Spacecraft TT&C Technology in China' collects selected papers from the 26th Conference of Spacecraft TT&C Technology in China held in Nanjing on October 16-19, 2012. The book features state-of-the-art studies on spacecraft TT&C in China with the theme of “Shared and Flexible TT&C Systems”. The selected works can help promote the technologies in standardization, informatization, communication networks and intelligence. Researchers and engineers in the field of aerospace engineering and communication engineering can benefit from the book.

SHEN Rongjun is the Academician of Chinese Academy of Engineering; QIAN Weiping is the Director General of Beijing Institute of Tracking and Telecommunications Technology.

Inhaltsverzeichnis

Frontmatter

Errata to—Chapter 1: Space-Based MA TT&C System and Technologies; Chapter 15: Flexible Hemispherical Simultaneous Multi-Beam TT&C Technology

Jianping Hu, Hongjun Yang, Maoge Xu, Pengyi Wang, Yongfei Kong, Haizhou Wu

Spacecraft TT&C System Design and Research

Chapter 1. Space-Based MA TT&C System and Technologies

Multiple Access (MA) service provided by Tracking and Data Relay Satellite System (TDRSS) is a space based MA TT&C and communication service using satellite relay. Spaced-based MA TT&C system is specialized in the implementation and application. In this paper the performance and technology development of S-band MA service provided by TDRSS is analyzed. As a feature of TDRSS SMA services, the major difference from that of conventional communication satellite is that its MA assignment has to be relayed and managed by ground station. Key technologies related to space based MA TT&C and communication are determined and their implementation solutions are proposed.

Jianping Hu, Hongjun Yang, Maoge Xu

Chapter 2. The Investigation of a Novel Reentry Telemetry System

With the development of the missile experimental research, the measurement bandwidth of super-fast-signal demands more and more (expected up to 100 MHz) in the reentry telemetry. However, the ability of the current PCM-PPK reentry telemetry system is limited. Also the PCM-PPK system is a non-universal system and impedes the improving of the telemetry technology. Based on the analysis of various modulation systems, the PCM-FM modulation system is proposed as a novel reentry telemetry system. The principle prototype of PCM-FM reentry telemetry baseband equipment is successfully developed with the code rate range from 10 to 100 Mbit/s.

Xingwen Ding, Ming Chen, Xifu Huang, Ling Wu

Chapter 3. Research on United Tracking Schemes Based on a New Information Frame Format

In a Tracking, Telemetry and Command (TT&C) system for the upper-stage of a launch vehicle, a mass amount of instant and dynamic telemetry information need to be transmitted to the ground station from the launch vehicle. Meanwhile, ranging accuracy is seriously affected because the energy of telemetry information is more than the ranging information. To meet requirements for transmission of different information on the downlink of launch vehicle upper-stage, a new information frame format based on isochronous service and insert service is proposed. Moreover, three united tracking schemes including direct switch, free oscillation switch and accumulation branch assisted switch are proposed. The performance of the three schemes is simulated with MATLAB. The result shows that all three schemes can implement the switch between different loops, but there exists a phase jump at 20 ms both in direct switch and free oscillation switch. Only the accumulation branch assisted switch can switch smoothly. Therefore, it is the best scheme. The research findings are of high significance for practical applications.

Haitao Nan, Zhiqiang Li, Wenming Zhu, Peng Jia, Feilong Li

Chapter 4. A Research on the Architecture Design of Space Tracking, Telemetry and Control Networks

The development of Chinese space tracking, telemetry and control (TT&C) networks are facing the challenge of informatization. In order to meet this challenge, it is necessary to research the architecture of the space TT&C networks according to the total development planning of our country’s aerospace industry. This paper discusses the complex characters of space TT&C networks and then applies the Multi-Living Agents (MLA) theory to design and construct the future space TT&C networks. With this methodology, the objective of system design is concerned not only with the indicators of the system, but also the operation mechanism of the system. The significance of this theory in such architecture design is also indicated.

Xiangyang Lu, Lijuan Jia, Jin Hu, Jianguang Wu, Shiyong Du

Chapter 5. Discussion on Integration Management of TT&C Information

To support more and more satellite and launch vehicle missions, tracking, telemetry and command (TT&C) system is challenged by requirements of more equipments operation, more complex system management and more intelligent decision-making. With the development of information technology (IT), promoting IT usage in TT&C system is the only way to meet the challenge. Based on the views of IT evolution stages, information integration issues, combined with TT&C system, this paper proposed a TT&C information integration management model and a corresponding application system, which both have three levels, a base-level with automation as subject, a middle-level with process management as subject and a high-level with intelligence as subject. Comprehensive discussion shows that the information integration stage in IT evolution is the key development stage for TT&C system. To improve information integration efficiency and ability, the three-layer model is an instructive model for practical application.

Yunsheng Hao, Linfeng Shang

Chapter 6. Informatization Maintenance of TT&C System Based on CBM

In view of the complexity of TT&C equipment and the difficulty of maintenance, a CBM construction being applicable to TT&C system was established according to the technology of condition-based maintenance and the OSA-CBM standard. By the study of state information management, performance evaluation, fault diagnosis and other key technologies, the condition-based maintenance functions for TT&C system were implemented initially. In the field of space TT&C, a new maintenance mode was established. It can meet the needs of the developing space launch missions and the management of on-orbit satellites.

Meng Ren, Weijing Zhou, Jianhua Guo, Zhongkai Guo

Chapter 7. Preliminary Research on Management of Crosslinks of Navigation Constellations and Their Security System

Crosslinks of a navigation constellation are designed for inter-satellite ranging and communication and autonomous navigation so that the constellation can function continuously without the support of globally distributed ground stations. Crosslinks can also realize some other extended applications. As a significant part of a satellite platform, crosslinks can improve the function of a constellation. However, management problems related to crosslinks have to be solved. This paper discusses the tasks of a crosslink management system and proposes a design of its function and topology based on the characteristics of the crosslinks of the navigation constellation. Meanwhile, the crosslink management model and security protection issues are also discussed.

Kunmei Cao, Taoming Chen, Bo Wang

Chapter 8. Study on Threats to Security of Space TT&C Systems

A space Tracking, Telemetry and Command (TT&C) system is a spaceflight support system and its security is of great significance. A framework of space TT&C system security threat assessment is proposed and it comprises of three aspects of factors: attack severity, value of asset and probability-to-succeed. An approach of qualitative gradation is introduced in the assessment. Based on the security threat assessment framework, threats to the security of space TT&C Systems during confrontation are analyzed. The analysis shows that threats of physical attacks on ground facility, RF jamming and High Power Microwave (HPM) weapon attack on satellites are outstanding and corresponding Protection measures are demanded.

Qi Wang, Bo Wang, Bin Wu

Chapter 9. Construction Strategy Research on New Generation Central Computer System of Launch Centre

Measure and launch, TT&C (telemetry, track and command), communication, meteorology and duty subsystems of current launch centre are all independent in information acquisition, transmission, processing and application. Experiment and launch hall and command hall are separately constructed. As the frequency of launch missions increased and refined degree of system management improved, current launch centre faces the challenges of flat command to future launch missions, enhancing economic performance and refined management. To solve these problems, the next generation launch centre is designed following new construction strategies including development of uniform command and decision support software, construction of integrated information processing and application platform, unification of software development model and information communication standard. The construction strategies are described in detail in the paper and evaluated from aspects of mission organization, technical progress and users’ requirements.

Shijie Song, Zhe Wang, Liping Zhang, Yongliang Yang

Chapter 10. The Application of OFDM in UAV Telemetry

OFDM will be a key technology in next mobile communications, and has potential applications in unmanned aerial vehicle (UAV) telemetry, so a UAV telemetry system based on OFDM is implemented on basis of analyzing its advantages in this paper. Firstly, the system scheme is presented. Then the baseband transmitter and receiver are designed in detail. All of OFDM baseband processing algorithms are accomplished in FPGA. The baseband test is developed, and the test result of PAPR is 12 dB, and the E

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lose is about 1 dB compared with the theoretical value. Finally, the UAV telemetry system is built, and the flying experiments are done. The experiment results show that OFDM is available technology in UAV telemetry.

Hailong Zhao, Jian Zhang, Jie Zhou

Chapter 11. TT&C System Design Based on Protocols and Master–Slave Structure

The current TT&C System is characterized by monotonous in application layer protocol and simple in structure, which results problems in heavy workload in Space Mission preparation, complicated system joint test, and inflexible of facility adaptability. In this paper, a new TT&C System Designing strategy based on protocols and Master–Slave Structure is raised. According to the characters of the existing TT&C System data exchange protocol, the TT&C System could be upgraded by adding in supplementary protocols and data types to realize “join and play” function. Thus, the system joint test workload can be reduced, Space Mission preparation time can be shortened, and flexibility of TT&C System can be improved.

Feng Xu, Xiaofang Wang, Jianhong Zhao

Chapter 12. Study on the Application of LT Code Technology in Deep Space Communications

Deep space communications have such characteristics as long delay, high code error rate and easily broken links, etc. Easily broken links may lead to a certain degree of random flash-break of TT&C signals, which in turn will result in the unrecoverable loss of data. Luby Transform (LT) code (Luby in Proceedings of the 43rd Annual IEEE Symposium Foundations of Computer Science (FOCS), pp. 71–280 (2002)) technology is an excellent special data recovery technology for scattered data. It can solve the issue of data frame loss in deep space communications, and is very suitable for the reliable transmission of large volume of data, but it cannot improve the code error performance of transmission. Therefore considering the issues such as high code error rate and easily lost data in deep space communications, the paper studied and implemented the concatenation of LT code and LDPC/TPC code, expected to provide more reliable solution for the acquisition of deep space communications data.

Tong Guo, Daheng Zhao, Xudong Li

Chapter 13. Application of Multicarrier 2-Dimension Spread Spectrum in Aerospace TT&C

Application of multicarrier 2-dimension spread spectrum (MC-2D-SS) is proposed in the field of aerospace TT&C systems to enhance their resistance to interference during mission operations. In principle, MC-2D-SS is the combination of direct sequence spread spectrum (DS-SS) and multicarrier CDMA (MC-CDMA). Therefore, it has both the characteristics of signal hiding of DS-SS and anti-inter-symbol interference (ISI) and anti-interference of MC-CDMA. A design of transmitter and receiver using MC-2D-SS is given for aerospace TT&C. Discussion is given to key technical issues of design, e.g. synchronization, ranging, anti interference and channel estimation, and a rough synchronization scheme is recommended. As a result, the TT&C system not only fully meets mission operation requirements, but also has high spread spectrum gain, strong anti-interference performance, ISI resistance capability and adaptive transmission characteristics.

Jinbao Wang, Wenge Yang, Dong Liu

Chapter 14. Parameter Estimation of Frequency Hopping Signals Based on Time Frequency Analysis

Frequency hopping signal is analyzed in this paper using various time frequency analysis methods, including short time Fourier transform (STFT), Wigner-Ville distribution (WVD) and its improvements. By comparing the hopping patterns derived from these methods, spectrogram (SP) is chosen to estimate the hopping period, hopping timing and hopping frequency, as well as to obtain some valuable measurement results. Finally, a practical method is proposed to test the parameters of frequency hopping signals.

Wenge Yang, Meng Li, Libin Wang, Hao Zhang

Mission Operations and Management

Chapter 15. Flexible Hemispherical Simultaneous Multi-Beam TT&C Technology

This paper first introduces the background and overseas research status of the hemispheric array antenna. An implementation structure, combining sub-array active phased antenna array with multi-plane digital beamforming, is proposed. Then, its design feature, development, expected performance and related key technologies are discussed, and finally a brief summary is given.

Pengyi Wang, Yongfei Kong, Haizhou Wu

Chapter 16. Fast Identification and Modification of Angle Error Based on Prior Information of Velocity-Measurement Radar

A new method on the use of prior information is proposed to solve the problem that the accuracy of measured angles with a velocity-measurement radar is low. The method of amending the angle error of optical and pulse radar is applied to the angle data correction of velocity-measurement radar. So a method of amending error superposition of many complicated components is proposed, and the conventional method of amending angle error is improved. By eliminating the error item in measured angle data of the velocity-measurement radar, the accuracy of measured angle is improved and the measured angle data can be fully used in computing the trajectory. When the angles are amended, the steady and credible trajectory parameters can be computed. Thus, the trajectory measuring accuracy is improved.

Jianping Pan, Bo Qiang, Zongwei Liu, Yanan Hu, Shengxi Wang

Chapter 17. Optimized Simulation Analysis of Netted Ground-Based Radars for Near Space Vehicle

Firstly the elements, functions and flight features of the Near-Space Vehicles (NSVs) are analyzed in this paper. Then the problems on tracking, telemetry and control (TT&C) of the NSVs and the requirements of the Ground-Based Radars for NSVs objects are analyzed. Based on the deployment scheme of the future Ground-Based Radars, the optimized usage of the TT&C resources of the ground navigation area is designed and simulated to fulfill the needed accuracy information of TT&C for the flight of the NSVs under limited resources condition. Several deployment schemes are simulated and optimized in this paper. The simulation results show that through deployment optimization to existing schemes, the performances, i.e., efficiency and resource consumption, are improved.

Daqing Chen, Dan Liu, Rongchun Wang, Zhe Zhang

Chapter 18. Techniques of High Efficiency and Linearity Transmitter

Linearity and power efficiency of transmitter are the two major concerns in designing modern wireless communication system. Consequently various competitive and complementary technologies have been investigated. The design techniques of high efficiency power amplifier and advanced linearity transmitter architecture are generally introduced in this paper, and the implementation of several efficiency enhanced power amplifiers, such as Doherty power amplifier, inverse class E power amplifier with series tunable parallel resonant tank, multiband high efficiency power amplifier based on CRLH transmission lines and wideband (0.9–2.7 GHz) high efficiency power amplifier, are also presented. Furthermore, digital predistortion is used to increase the linearity of inverse class E power amplifier, and a high degree of spectral suppression for out-of-band is achieved. Moreover, the telemetry transmitter, which is suitable for 2 Mbps PCM signal, is developed based on high efficiency class E power amplifier. The results show the switching mode amplifiers have potential application in improving the power efficiency of telemetry transmitter.

Tao Cao, Rong Zeng, Youjiang Liu

Chapter 19. Analysis of Feed Defocus’s Effects on a Ka-Band Parabolic Antenna

The parabolic reflectors of deep space antennas are influenced by many facts, such as fabrication error, gravity and thermal deformation, which induce the feed deviating from the focal point of the paraboloid. The feed defocus would introduce phase errors over the paraboloidal dish, and degrade the antenna performance. In this paper, first the feed defocus is discussed from the view of reflector geometry, and the corresponding path length difference is derived. Then the effects on a Ka-band deep space parabolic antenna with 35-m diameter are analyzed as an example. From geometrical analysis and numerical calculations, the effects of feed defocus on some important antenna parameters such as gain, sidelobe level and pointing error are given and summarized. Finally, a method of feed defocus calibration is proposed.

Guolong He

Chapter 20. Study on ISAR Imaging of Stepped-Frequency Chirp Signal

The application of the stepped-frequency Chirp signal on the wideband phased-array radar was analyzed in this paper. The window function was used to design the radar key parameters to minimize the ghost peak and the sampling loss. Then a velocity compensation method was presented to solve the Doppler Effect. Then the effects of the aperture fill time on the antenna direction pattern were also analyzed and a grouping phase matching rule was given. At last was the imaging result of the real data, which shows the validly of the proposed methods.

Haotian Yuan, Shuliang Wen, Zhen Cheng

Chapter 21. A Carrier Acquisition and Tracking Algorithm for High-Dynamic Weak Signal

This paper studies acquisition and tracking of carriers by the Tracking, Telemetry and Command (TT&C) systems in low Signal-to-Noise Ratio (SNR) and high dynamic conditions for deep space applications. An associated carrier acquisition and tracking algorithm is proposed and it features FFT frequency-domain shift and accumulation algorithm in combination with variable bandwidth FLL-PLL algorithm with Doppler rate pre-compensation. The algorithm not only captures signal with high dynamics and low SNR but also achieves high tracking accuracy. Simulation results show that the proposed associated frequency estimation algorithm is capable of carrier frequency estimation with an error less than 0.5 Hz and it tolerates high Doppler dynamics under E

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as low as 3 dB.

Ruifeng Duan, Rongke Liu, You Zhou, Qingping Song, Zhiqiang Li

Chapter 22. An Acquisition Algorithm for DS/FH TT&C Signal Using Subband-Accumulation Method

The problem of fast acquisition of Direct Sequence/Frequency Hopping (DS/FH) spread spectrum signal is studied. With the existence of ionospheric dispersion, the carrier phase continuity of a phase-coherent FH system is disrupted and the complexity of acquisition is drastically increased. By searching the Total Electron Count (TEC), i.e. the electron density, along the path length, the receiver is capable of compensating for the phase pattern of local replica FH signal and performing quasi-coherent acquisition. A new acquisition strategy named Band Division Accumulation is proposed. It is proved that the strategy can broaden the TEC search period and thus reduce search complexity. The connection between the number of sub-bands and energy loss is analyzed. The accumulation loss of acquisition can be adjusted by altering the number of sub-bands, providing flexibility to design of receivers.

Xiao Chen, Zhiqiang Li, Wenming Zhu, Dekan Lou

Chapter 23. Anti-Fading Analysis of Diversity-Synthesized Technology

This paper analyzed the anti-fading performance of diversity-synthesized technology in FM telemetry engineering practice based on FM Baseband device principles and algorithms, designed experiment to simulate the situation that one direction rotational signal flash in engineering practice and tested the telemetry bit error rate. Through the discussion of device principle, experimental validation and engineering experiences, this paper analyzed the impact of differential-mode loop’s frequent loss of lock in FM telemetry engineering practice. It is normal in FM telemetry engineering practice that the fast fading of FM telemetry one direction rotational signal in a short time causes differential-mode loop loss of lock frequently, the technology of diversity-synthesized can be used as anti-fading effectively in FM telemetry engineering.

Mingxin Kou, Jun Yan

Chapter 24. Analysis on the Application of Feed-Forward Technology for Space Tracking, Telemetering and Control Ships

Shipborne radar devices are influenced by ship-swaying in terms of their tracking accuracy, especially under bad sea conditions, which making it very important to employ a technique which not only maintains tracking stability but also isolates ship-swaying effects. A scheme which compensates antenna azimuth and elevation angles for feed-forward controls is proposed. First the radar ship-swaying feed-forward compensation technique is introduced, followed by feed-forward equations deduced by compensating tracking errors caused by ship-swaying and target movements. Then, the deduction results are analyzed and concluded that ship-swaying feed-forward data can be validly produced without target distance values provided.

Dingxin Yang, Ting Yuan

Chapter 25. A Telemetry Data Fusion Method Based on Optimal Weighted

To solve the difficult problem of multi-sources telemetry data use in spaceflight TT&C, data pretreatment procedure and data fusion method are studied in this paper. On basis of the existing telemetry data processing, a new data pretreatment procedure is designed, realizing the function of data screening, extracting and selecting. A new data fusion method based on optimal weighted is put forward as well. The algorithm and distribution principle for optimal weighted values are discussed and presented. In the end, after the data pretreatment and fusion stages, a more accurate and reliable data result is provided. Theoretical analysis and real mission data implication show that data quality after pretreatment and fusion is improved obviously. It enhances the precision of data processing, and reduces risks caused by error data. The method has great value in engineering application, and can make reference for the further research of multi-sources data processing.

Ping Jiang, Yangwei Dong, Xuemei Zou

Chapter 26. A Data Fusion Method of Multi-Sources Measurement Data Based on Federated UKF Filter

To ensure the tracking reliability and accuracy, and to increase the utilizing efficiency of measurement data in space flight tracking, a data fusion method in real-time orbit tracking based on federated UKF filter is put forward. The key technology of the multi-source measurement data fusion scheme is also analyzed in this paper. The computer simulation shows that the reliability of the real-time orbit tracking can be increased remarkably and the tracking accuracy can be increased by thirty percent. In this method, the fused ballistic curve is continuous and the convergence can meet the requirement of real-time guidance, which has great meanings on the overall level of spaceflight commending and controlling system.

Hong Chen, Jian Jiang, Lin Wang

Chapter 27. Dim and Weak Target Detection Technology Based on Multi-Characteristic Fusion

As the signal of small weak target is weak, its characteristic information is prone to weakening and loss and is difficult to maintain stability. In this paper, a self-learning mechanism is built using continuous signal correlative characteristics. The method is based on K-L transform fusion technology and D-S theory of decision-making. Meanwhile, the fusion technology of “fusion after the first decision-making” and “decision-making after first fusion” organic integration is developed. To verify the detection capability of this technology for small dim targets, a new type of tracking processor is developed. It processes more than one hundred groups of raw image data divided into two groups. The image data is taken by a space target surveillance telescope. Experimental results show that dim targets can be detected and tracked stably and reliably using this technology. Also provided with a complex background suppression and anti-jamming capability, a target can be detected stably and reliably when its SNR is about 1.2.

Jia Tang, Xin Gao, Gang Jin

Chapter 28. Distortion Correction for Optical Measurement Systems in a Test Range

A flexible method for timely correction of distortion of optical measurement system in a test range environment is proposed to eliminate the negative impact of distortion on accuracy. The fitting relationship between the measured miss distance and real miss distance is solved because theoretically the compound angle is unchanged. Operation of the method is simple and quick and there is no need of special-purpose instruments. The method is validated in an experiment of distortion correction. The result of data analysis shows that the measurement accuracy is increased from 100 to 20 arc s. Therefore, it has a high value for extended application.

Rujie Wang, Liangliang Wang, Lei Zhang, Jia Tang

Information Transfer and Processing

Frontmatter

Chapter 29. Research on Multi-Path QoS Routing Strategy for the Satellite Network

The satellite network, together with the traditional ground network, constitutes the Space–Ground Interconnection Network (SGIN), which can provide global coverage for communications and become an important developing trend of the next generation network. Currently, there exist lots of routing algorithms that are based on the characteristics of satellite networks. However, most of them focus on a single transmission performance index while ignoring others. A multi-path parallel routing strategy for the satellite network based on Quality of Service (QoS) requirements and information of inter satellite links (ISLs) is proposed. Firstly, the strategy utilizes the historical and near-real-time information of the ISLs to conduct off-line routing computing on the ground. After that, real-time information of the ISLs and QoS requirements for data communications will be reconsidered on board to adjust the pre-computed routing scheme. Finally, data transmission will be allowed to take place on several routes between the source and the destination in parallel. This strategy not only ensures high arrival rate and low latency of data transmissions, but also fully utilizes link resources of the satellite network and balances the workloads among ISLs efficiently.

Guanghua Song, Mengyuan Chao, Bowei Yang, Hua Zhong, Yao Zheng

Chapter 30. Constant Modulus Blind Equalization Analysis for High Speed Implementation

Constant modulus equalization algorithm (CMA) is widely used for mitigating inter-symbol interference (ISI) in various communication systems, for its robustness and low computational complexity. In practice, signed error CMA may be adopted to simplify the implementation. However, the simplification severely degrades its steady state performance. In this paper, a detailed analysis is taken to compare the mentioned two algorithms in Field Programmable Gate Arrays (FPGA) implementation. Furthermore, a novel error function is proposed for the high speed implementation consideration. Numerical simulation demonstrates that the proposed algorithm behaves much better than the reference with similar computational complexity, which makes the proposed algorithm more suitable for the area of high speed applications.

Dalong Yang, Dahai Chen, Wen Kuang

Chapter 31. Study on Space Mission IP Network QoS Technologies

This paper addresses the QoS technologies and strategies in space mission IP network. It is analyzed of the primary factors, including that causes congestion and influences the QoS performance. This paper aims to provide a top-level design on the QoS strategy and commits suggestions on the development of the QoS technologies in next generation space mission IP networks. With respect to the three potential congestion causes, i.e., excessive traffic access, unbalanced resource, and transmission mechanism, corresponding countermeasures are proposed. The QoS strategy of the space mission IP network is a systematic solution whose first role is to avoid congestion and guarantee the transmission with high priority when congestion occurs. The architecture of the QoS strategy of the space mission IP network can be summarized as a congestion avoidance mechanism based on traffic management, traffic output control, as well as additional service mechanisms. The congestion avoidance mechanism includes a set of strategies such as traffic policing, traffic shaping, and port rate limitation. The differential service mechanism includes a set of strategies such as service classification, priority marking, priority trust, and priority queue dispatch. With these strategies implemented, the end-to-end congestion management and QoS guarantee is achieved in the space mission IP network.

Yunjun Chen, Yan Liu, Shengwang Xu

Chapter 32. System Level Design of Address Allocation for a Private IP Network

IP address allocation is very important to data routing, inter-networking and OAM of large IP networks. In this paper, the high level architecture of a private IP network is presented firstly. Then its uniqueness is summarized as large scale multilayer network architectures, independent dual transferring routing of WAN, dual transferring planes of MAN/LAN, support of special requirement such as multicast and external networking. Various address allocation requirements from the above mentioned features are analyzed. Consequently, address spaces are divided according to the network type, routing, devices, and special application requirements. After that, each address space and its future evolution path is presented in details. Finally high level design and analysis of each allocation scheme is presented in sections according to the sequence of MAN, LAN, WAN, multicast and external networking. Field deployment result in the past 2 years has proved the success of the proposed address allocation plan.

Yalin Huang, Zongyin Zhao, Yan Liu, Xu Yao

Chapter 33. Research on the QoS Guaranteed Mechanism for the Private IP Network

In the private network, end-to-end QoS plays very important role for the real-time trial data transmission. Considering the features of the network and the respective QoS requirements, the general principle of QoS deployment is studied in this paper. Following the principles, the model of end-to-end QoS used in the private network is established firstly. Then it is analyzed and demonstrated that how to deploy the QoS strategy in the kernel layer, cluster layer, and access layer of the private network, respectively. Furthermore, the solution is also designed to accomplish the QoS for the burst data and in other special conditions. Finally, the all-around scheme of end-to-end QoS is proposed for the private network, which provided the theoretical basis and guidance for bringing the QoS into effect. The proposed mechanism could be a valuable reference of significant practical meaning for other private IP networks.

Lihua Liu, Tun Wu, Zongyin Zhao, Qian Zhang

Chapter 34. Distributed Data Service Platform Based on Narrowband Network Environment

A distributed data service platform is established mainly to solve the problem of data sharing among several data centers in narrowband WAN environment, provide continuously reliable and position-independent data services for the users and realize the objective of transmitting right information to right customer in right way (3R). The multi-center data service platform optimizes data consistency algorithm against WAN features (small bandwidth and long delay) based on network technology, distributed technology and parallel computing technology, using peer-to-peer cluster-based network system framework, combined with “Cloud storage” framework features, and provides such characteristic functions as strategy-based oriented sharing, priority control and network flow control as well as capabilities of synchronously sharing file data and database data facing overall situation and subject to unified management. The global distributed data redundancy storage also provides the users with new data backup for disasters; intelligent troubleshooting and inter-node high self-fusion features can provide efficient data fault-tolerant and data service recovery capabilities in case of fault of network or other hardware as well as continuous and non-stop data services for the users. System joint debugging in actual narrowband WAN operation environment shows that the system can fully meet the engineering demands in synchronous data sharing, system stability etc., and has good promoting value.

Xu Yan, Guoping Hu, Dahai Zhai

Chapter 35. Impact Analysis of the Leap Second to the Computer System in Beijing Aerospace Control Center

It analyzes the impact of the leap second at 07:59:60 July 1, 2012 to the timing system and applications in Beijing Aerospace Control Center (BACC), and proposes a solution for the leap second adjustment. First it introduces the source of the leap second. Next it articulates the timing system device, timing system clients, timing system topology, as well as their working mechanism. Then it describes the experiments on the leap second adjustment, presents the test contents, procedures, and results under the automatic and manual adjustment modes. It also presents the test results of the leap second adjustment under the NTP protocol. The test results indicate that the timing system devices work well under both automatic and manual adjustment modes, and the clients can synchronize with the timing system device in 4 s. When the adjustment is executed on the timing system device, the clients can synchronize with the timing system device after a pause of one second at the synchronization point. As for the NTP conditions, the clients can not synchronize within 5 min, and can synchronize immediately if the clients are rebooted. The leap second will make a big impact on the time-sensitive systems such as the TT&C devices and applications. It suggest that the leap second adjustment and synchronization need to be executed outside the critical command and control procedures, and a thorough implementation plan needs to be made. The most important point is that the synchronization must be after a delay of 4 s in the leap second adjustment.

Tonghua Li, Yuqiu Liang, Xia Wang

Chapter 36. The Exploration and Practice of Itinerant Testing for TT&C Device Software at the Launch Range

In view of the latent software faults and unsteadiness of telemetric tracking and command (TT&C) device software at the Launch Range, Software Itinerant Testing (SIT) is brought forward. Software faults are attributed to software manufacturer’s lack of necessary ability and shortage of process specification. Comparison of SIT and software project testing shows that SIT is a convenient activity that can be taken. The first time that SIT worked at launch range took about 8 weeks and found 52 faults. The result shows that TT&C device software is under unreliable state and with low robustness. SIT is an effective measure to solve TT&C Device software faults and improve the robustness and reliability of TT&C device software.

Peng Fu, Wei Li, Liang Zhao, Wei Zhang, Jing Zhang

Chapter 37. Research on Quality Assurance Method Based on Software Defect Analysis

Software defect information represents the characteristics of software processes and it can provide feedback to software quality assurance activities. The basic principle of software defect baseline is discussed, and a software quality assurance framework based on defect baseline feedback information is proposed. The relation between software activities and defect information collected through the process is studied. The statistical characteristics of defect information and it development trends along with the software process advance can reflect the effectiveness and efficiency of different quality assurance activities as feedback. Combined with practical projects, software defect metrics based on Orthogonal Defect Classification framework is built. The effectiveness and efficiency evaluation of quality assurance activities using the result of defects analysis is carried out with this quality assurance model to determine the direction of the QA improvements and help the software process integral improvement.

Qianran Si, Guoying Yan

Trajectory, Orbits and Navigation

Frontmatter

Chapter 38. Single-Station Orbit Determination with Astrometric Positioning and SLR Techniques

The principle of single-station orbit determination using astrometric positioning and SLR techniques is to add a laser ranging unit onto the optoelectronic telescope system, so as to conduct laser ranging and astrometric positioning angle measurement at the same time. By melting and processing all the data together, the new technique will achieve single-station orbit determination of the objects. In this paper, the actual measurement data of satellite Ajisai is analyzed for its single-station single-lap and multi-lap orbit determination. However, due to the limited amount of actual measurement data, objects of three types of orbit altitude have to be simulated and the single-station orbit determination analysis is just based on them in order to make the conclusion more universal. After studying the actual and simulated data, it turns out that for single-station single-lap orbit determination, the ranging measurement data (measurement duration longer than 4 min) will improve the orbit determination accuracy from several kilometers to tens of meters and the 24-h prediction accuracy from thousands of kilometers to several kilometers.

Guoping Chen, Xiaogong Hu, Yong Huang, Yong Yu, Zhenghong Tang, Zhongping Zhang, Yezhi Song

Chapter 39. On Nominal Formation Flying Orbit with a Small Solar System Body

It is very difficult for an explorer to orbit a low-mass and irregularly shaped small body in the solar system. In this case, formation flying with the small body is a workable solution. This paper discusses two strategies of formation flying based on two different dynamic models. The orbit resulted from the C–W equation and the halo orbit around libration point L1 in the Circular Restricted Three-body Problem (CRTBP) are considered as nominal orbit respectively. Numerical simulation indicates the effect of the magnitude of μ on the stability and other features of the halo orbits, where μ is a parameter weighing the gravity of the small body. The result shows that the CRTBP is more fuel-saving and therefore a more appropriate dynamic model for solving the formation flying problem. This paper also works out a dynamic model involving solar radiation pressure. Simulation result shows that, in this condition, the C–W equation has no significant advantage.

Yuhui Zhao, Shoucun Hu, Xiyun Hou, Lin Liu

Chapter 40. On Orbit Control Utilizing Solar Sails Around Asteroids

The interest of exploring asteroids has been growing over these years due to their primordial origins and possible economic benefits. The gravities of the asteroids are mostly very small and irregular, so it is necessary to study the orbits around them with special treatment. In this paper, two kinds of nominal orbits for probes are firstly proposed. One kind is around the collinear libration points of the restricted three-body problem formed with the Sun, the asteroid and the probe. The other kind is the formation flying orbits around the asteroid. Due to the inevitable existence of errors in practice, station keeping of these two kinds of nominal orbits is necessary. Solar sail propulsion is used in this paper. Two control techniques including varying the solar sail area and varying the solar sail pitch and yaw angles are considered. The linear optimal feedback control law is used. Numerical simulations are made to both kinds of nominal orbits. The results show that the controlled orbits converge to the vicinity of the nominal orbits rapidly. The technique of varying the solar sail pitch and yaw angles is better than varying the solar sail area.

Shengxian Yu, Xiyun Hou, Lin Liu

Chapter 41. Orbit Determination of Lunar Probe Brake Course Based on Compensation to Dynamic Parameters

During orbital maneuver process, the probe relays on propulsion system to generate thrust acceleration, which tunes attitude and orbit. The complicated course of propulsion makes thrust hard to be modeled. The difficulty of precisely modeling thrust acceleration mainly includes two aspects: firstly, the begin-and-final epochs of attitude control and orbital control are not easy to determine; secondly, the acceleration of attitude control and orbital control are not easy to model accurately. It focuses on modeling and building nearly real-time filter to estimate dynamic parameters to compensate the uncertainty of the force model during the maneuver process. In the first section, the background of modeling thrust acceleration was introduced. In

Sect. 41.2

, the linear attitude control acceleration and the average orbital control acceleration model were used to describe the accelerating motion. In

Sect. 41.3

, an Extended Kalman Filter (EKF) was developed for the orbit determination with thrust involved, also the variation equation about state vector with dynamic parameters were put forward for the linearization of the non-linear dynamic system. In

Sect. 41.4

, the third lunar orbital brake of Chang’E-1 was processed to ascertain that the algorithm developed here can estimate the acceleration precisely during the continuous thrust maneuver process. EKF Results show that compared with the precise post-results, the error is 216 m in semi-major axis and 0.001 in eccentricity.

Shijie Chen, Lan Du, Zhongkai Zhang, Quying Danzeng, Ruopu Wang, He Wang, Qifu Zhang

Chapter 42. A Modified IAE Algorithm for GNSS and IMU Integration

Innovation-based adaptive estimation (IAE), which is one of the proved Adaptive Kalman Filter (AKF) algorithms, can improve the accuracy of GNSS/IMU combined navigation system based on the condition that the received GNSS measurements are independently accurate enough. However, IAE is more likely to be subjected to bias and non-convergence with degraded measurements accuracy due to GNSS signal outage or low-cost receiver. In order to maintain the performance of integrated GNSS/IMU system with the coexistence of less accurate measurements, a modified IAE algorithm is proposed in this paper. The algorithm, named “IAE with measurements discarding strategy” (IAE-D), monitors the quality of the estimations and measurements in real-time, and discards the measurements when the estimations are accurate enough or the measurements are less qualified. Field test was carried out. Noise was imported to simulate different levels of measurements deterioration. Performance comparison between Extended Kalman Filter (EKF), IAE and IAE-D has been executed with real data. The results demonstrate that IAE-D has magnificent advantage over EKF and IAE in regard to stability and accuracy when the power level of measurements interference is relatively high.

Peng Li, Chan Li, Xiangjun Wu, Zhonggui Chen
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