Reliable transmission of consultative committee for space data systems file delivery protocol in deep space communication

In consultative committee for space data systems（CCSDS） file delivery protocol（CFDP） recommendation of reliable transmission,there are no detail transmission procedure and delay calculation of prompted negative acknowledge and asynchronous negative acknowledge models.CFDP is designed to provide data and storage management,story and forward,custody transfer and reliable end-to-end delivery over deep space characterized by huge latency,intermittent link,asymmetric bandwidth and big bit error rate（BER）.Four reliable transmission models are analyzed and an expected file-delivery time is calculated with different trans-mission rates,numbers and sizes of packet data units,BERs and frequencies of external events,etc.By comparison of four CFDP models,the requirement of BER for typical missions in deep space is obtained and rules of choosing CFDP models under different uplink state informations are given,which provides references for protocol models selection,utilization and modification.

《空间数据与信息传输系统 航天器SpaceFibre总线通信协议》国家标准解读

SpaceFibre总线是专门面向新一代智能航天器在轨海量数据可靠传输设计的新型超高速组网互联技术,其提供了优先级、带宽预留和时隙规划等多种服务质量保证机制,支持最高50Gbps的超高链路传输带宽,具备数据检错重传、链路状态机管理、多信道冗余与平滑降级等多层级容错机制,在航天器安全关键应用领域具有显著优势。制定GB/T 43670—2024《空间数据与信息传输系统SpaceFibre总线通信协议标准》,对于支持SpaceFibre核心芯片和网络系统研制,保证各类星载高性能处理设备之间高速通信接口一致性和匹配性,实现整星系统快速集成测试和不同航天器之间产品可重用性具有极其重要的意义。

Research on multiple elimination methods in inverse data space based on randomized singular value decomposition

Based on surfaced-related multiple elimination （SRME） , this research has derived the methods on multiples elimination in the inverse data space. Inverse data processing means moving seismic data from forward data space （FDS） to inverse data space （ IDS） . The surface-related multiples and primaries can then be sepa-rated in the IDS, since surface-related multiples wi l l form a focus region in the IDS. Muting the multiples ener-gy can achieve the purpose of multiples elimination and avoid the damage to primaries energy during the process of adaptive subtraction. Randomized singular value decomposition （ RSYD） is used to enhance calculation speed and improve the accuracy in the conversion of FDS to IDS. The synthetic shot record of the salt dome model shows that the relationship between primaries and multiples is simple and clear, and RSVD can easily eliminate multiples and save primaries energy. Compared with conventional multiples elimination methods and ordinary methods of multiples elimination in the inverse data space, this technique has an advantage of high cal-culation speed and reliable outcomes.

Scientific data products and the data pre-processing subsystem of the Chang'e-3 mission

The Chang＇e-3 （CE-3） mission is China＇s first exploration mission on the surface of the Moon that uses a lander and a rover. Eight instruments that form the scientific payloads have the following objectives： （1） investigate the morphological features and geological structures at the landing site; （2） integrated in-situ analysis of minerals and chemical compositions; （3） integrated exploration of the structure of the lunar interior; （4） exploration of the lunar-terrestrial space environment, lunar sur- face environment and acquire Moon-based ultraviolet astronomical observations. The Ground Research and Application System （GRAS） is in charge of data acquisition and pre-processing, management of the payload in orbit, and managing the data products and their applications. The Data Pre-processing Subsystem （DPS） is a part of GRAS. The task of DPS is the pre-processing of raw data from the eight instruments that are part of CE-3, including channel processing, unpacking, package sorting, calibration and correction, identification of geographical location, calculation of probe azimuth angle, probe zenith angle, solar azimuth angle, and solar zenith angle and so on, and conducting quality checks. These processes produce Level 0, Level 1 and Level 2 data. The computing platform of this subsystem is comprised of a high-performance computing cluster, including a real-time subsystem used for processing Level 0 data and a post-time subsystem for generating Level 1 and Level 2 data. This paper de- scribes the CE-3 data pre-processing method, the data pre-processing subsystem, data classification, data validity and data products that are used for scientific studies.

Modeling and Simulation Study of Space Data Link Protocol

This research paper describes the design and implementation of the Consultative Committee for Space Data Systems (CCSDS) standards REF _Ref401069962 \r \h \* MERGEFORMAT [1] for Space Data Link Layer Protocol (SDLP). The primer focus is the telecommand (TC) part of the standard. The implementation of the standard was in the form of DLL functions using C++ programming language. The second objective of this paper was to use the DLL functions with OMNeT++ simulating environment to create a simulator in order to analyze the mean end-to-end Packet Delay, maximum achievable application layer throughput for a given fixed link capacity and normalized protocol overhead, defined as the total number of bytes transmitted on the link in a given period of time (e.g. per second) divided by the number of bytes of application data received at the application layer model data sink. In addition, the DLL was also integrated with Ground Support Equipment Operating System (GSEOS), a software system for space instruments and small spacecrafts especially suited for low budget missions. The SDLP is designed for rapid test system design and high flexibility for changing telemetry and command requirements. GSEOS can be seamlessly moved from EM/FM development (bench testing) to flight operations. It features the Python programming language as a configuration/scripting tool and can easily be extended to accommodate custom hardware interfaces. This paper also shows the results of the simulations and its analysis.

Design of THz Space Application System

Two kinds of space applications of THz band are proposed. A novel method for the THz band signal propagation in the satellite-earth link is studied in order to overcome the huge loss in the atmosphere. The THz signal should be transformed to Ka band by data processor on satellite, and then be transmitted to the earth station in order to avoid the THz loss in the atmosphere. The design can realize at least 10 Gbps space communication or data relay. Furthermore, three aspects of challenges in THz band are analyzed.

Application Research on Space Laser Communication in Bistatic Radar System

There exist three synchronizing problems in the bistatic radar system that some signals of the radar receiver must be synchronized with those of the radar transmitter. Several methods realizing data transmission, which are used to complete the synchronization existing in the bistatic radar system, are described. Then a new idea is brought forward that employs space laser communication in the bistatic radar system to realize its data transmission. The theoretic analysis of the idea's usability and its merits are discussed in details. Finally the latest development of space laser communication is introduced, and the utility of the idea is pointed out further.

Overview of multirate sampled-data control system

The basic analysis and synthesis approaches for multirate sampled-data control system are reviewed. After giving the definition and some properties of multirate system are given, its origination, development and design methods are discussed in detail. Finally, some remarks, expectations and conclusions on the present research status and the research directions are given.

Research and Application of Maize Precision Intelligence Spatial Decision Support System

In order to solve the problem of the maze precision fertilizer,soil fertility evaluation,soil fertility classify and yield projections,the geographic information system with spatial information processing functions,spatial data mining techniques with spatial information analysis capabilities,expert system technology in the field of artificial intelligence,traditional information management systems and decision support system were effectively integrated in this study,and the statistical analysis method of GIS and data visualization were combined to design and implement the maize precise intelligent space decision-making system.This system had greatly improved the decision-making ability in agricultural production carried out by agricultural management.

An image compression method for space multispectral time delay and integration charge coupled device camera

Multispectral time delay and integration charge coupled device （TDICCD） image compression requires a low- complexity encoder because it is usually completed on board where the energy and memory are limited. The Consultative Committee for Space Data Systems （CCSDS） has proposed an image data compression （CCSDS-IDC） algorithm which is so far most widely implemented in hardware. However, it cannot reduce spectral redundancy in mukispectral images. In this paper, we propose a low-complexity improved CCSDS-IDC （ICCSDS-IDC）-based distributed source coding （DSC） scheme for multispectral TDICCD image consisting of a few bands. Our scheme is based on an ICCSDS-IDC approach that uses a bit plane extractor to parse the differences in the original image and its wavelet transformed coefficient. The output of bit plane extractor will be encoded by a first order entropy coder. Low-density parity-check-based Slepian-Wolf （SW） coder is adopted to implement the DSC strategy. Experimental results on space multispectral TDICCD images show that the proposed scheme significantly outperforms the CCSDS-IDC-based coder in each band.

2D joint inversion of CSAMT and magnetic data based on cross-gradient theory

A two-dimensional forward and backward algorithm for the controlled-source audio-frequency magnetotelluric （CSAMT） method is developed to invert data in the entire region （near, transition, and far） and deal with the effects of artificial sources. First, a regularization factor is introduced in the 2D magnetic inversion, and the magnetic susceptibility is updated in logarithmic form so that the inversion magnetic susceptibility is always positive. Second, the joint inversion of the CSAMT and magnetic methods is completed with the introduction of the cross gradient. By searching for the weight of the cross-gradient term in the objective function, the mutual influence between two different physical properties at different locations are avoided. Model tests show that the joint inversion based on cross-gradient theory offers better results than the single-method inversion. The 2D forward and inverse algorithm for CSAMT with source can effectively deal with artificial sources and ensures the reliability of the final joint inversion algorithm.

An Adaptive Transmission Scheme for Deep Space Communication

Deep space communication is quite different from conventional ground communication due to its time-varying,complexity and large signal delay,which consequently affects communication quality and system efficiency.Adjusting the transmission parameters when the channel environment changes during the communication can guarantee the performance index of the system,and therefore improve communication efficiency. An adaptive transmission scheme of transceiver based on Consultative Committee for Space Data Systems(CCSDS)protocols is proposed in this paper. According to the variation of the deep space channel,the symbol rate of transmission data is adjusted dynamically by estimating the signal-to-noise ratio(SNR) of the receiver in real time and adjusting the channel environment. This scheme can improve the channel utilization and system throughput under the premise of limiting the system bit error rate. Furthermore,this scheme is successfully implemented in Xilinx Virtex-5 FPGA board.

Urban Big Data and the Development of City Intelligence

This study provides a definition for urban big data while exploring its features and applications of Chi- na＇s city intelligence. The differences between city intelligence in China and the ＂smart city＂ concept in other countries are compared to highlight and contrast the unique definition and model for China＇s city intelligence in this paper. Furthermore, this paper examines the role of urban big data in city intel- ligence by showing that it not only serves as the cornerstone of this trend as it also plays a core role in the diffusion of city intelligence technology and serves as an inexhaustible resource for the sustained development of city intelligence. This study also points out the challenges of shaping and developing of China＇s urban big data. Considering the supporting and core role that urban big data plays in city intel- ligence, the study then expounds on the key points of urban big data, including infrastructure support, urban governance, public services, and economic and industrial development. Finally, this study points out that the utility of city intelligence as an ideal policy tool for advancing the goals of China＇s urban de- velopment. In conclusion, it is imperative that China make full use of its unique advantages-including using the nation＇s current state of development and resources, geographical advantages, and good hu- man relations-in subjective and objective conditions to promote the development of city intelligence through the proper application of urban big data.

A Comparative Study on Two Techniques of Reducing the Dimension of Text Feature Space

With the development of large scale text processing, the dimension of text feature space has become larger and larger, which has added a lot of difficulties to natural language processing. How to reduce the dimension has become a practical problem in the field. Here we present two clustering methods, i.e. concept association and concept abstract, to achieve the goal. The first refers to the keyword clustering based on the co occurrence of

《空间数据与信息传输系统 航天器CAN总线通信协议》国家标准解读

国家标准《空间数据与信息传输系统航天器CAN总线通信协议》(GB/T 43671—2024)旨在规范和指导航天器CAN总线的设计与应用,该标准覆盖了航天器CAN总线通信的物理层协议、数据链路层协议、总线通信过程与协议、可靠性设计要求等,为空间数据与信息的可靠传输提供有效保障。为促进该标准在航天工程领域有效实施与广泛应用,本文从标准的诞生背景、目的意义、主要内容等方面进行了剖析与解读。

《空间数据与信息传输系统航天器1553B总线通信协议》国家标准解读

1553B总线在我国已广泛应用于各式各类的航天器中,取得了丰富的应用实践经验积累。制定GB/T 43669—2024《空间数据与信息传输系统航天器1553B总线通信协议》是为了解决1553B总线在各型号任务中制定的应用通信协议不够一致、难以跨任务、跨组织重用的问题,解决与底层1553B总线协议衔接的标准化设计问题。该标准提炼总结了我国1553B总线在航天器上应用实践的共性设计,借鉴了ECSS-E-ST-50-13C写作风格和思路,兼顾了与其在概念上和设计上的衔接,有利于今后的国际合作。本文介绍了该标准制订的背景、目的意义,以及标准主要内容的编制思路。

基于云原生的航天发射一体化指挥显示系统数据引擎设计

针对航天发射领域多种类与多任务并行的发展趋势,剖析了现行指挥显示系统数据引擎软件架构的局限,通过构建多级缓存,优化Flink任务调度算法,实现了基于云原生的数据处理机制和数据引擎系统。系统采用微服务架构,以容器技术打包并布设了面向航天领域的数据接入、分布式计算、数据多级缓存等核心模块,有效缓解了系统运行压力,提高了数据处理与任务态势信息获取的时效性,为数据可视化与辅助判决提供了更加全面精确的数据支撑。在整体开发运维流程上融入DevSecOps思想,支持快速开发、部署和交付,为下一代指挥显示系统的研发提供了参考。

基于SOIS架构的星载设备虚拟访问设计

为了更好地解决航天器设备间互操作难、软件通用性弱等问题,文章对空间数据系统咨询委员会(CCSDS)的航天器星载接口业务(SOIS)架构中,基于标准业务和电子数据单(EDS)的星载数据系统架构进行了分析,提出了以标准业务和EDS的融合方式开展设备虚拟访问的设计方法。对设备发现、设备枚举、设备访问、设备虚拟、数据池以及访问管理业务及其相关原语进行了实例化设计,结合1553B总线为实现即插即用而设计的EDS,开展了初步的测试验证,证明了其可行性。文章提出的星载设备虚拟访问融合方式可为标准业务及其相关的电子数据单设计提供参考,有助于系统快速集成、软硬部件的重用。

移动式三维激光扫描系统在地铁隧道病害检测中的应用

在地铁运营过程中,地铁隧道及其附属构建筑物会出现结构渗水、掉块和环片错台等病害情况,传统检测方法存在难以精确量化、检测效率低、容易漏检等缺点。为了解决这些问题,将移动三维激光扫描系统应用于地铁运营病害检测中,首先采集隧道空间的三维点云信息,再对轨道移动小车、架站式、手持式等不同移动三维激光扫描系统内外业效率、精度情况进行对比分析,总结移动式三维激光扫描系统内外业的生产流程,结合地铁工点采集的隧道三维点云数据,探讨不同三维激光扫描系统的适用性,并实现隧道病害检测的人工智能算法,以提升地铁运营监测效率和病害识别的准确率。结果显示,手持式三维激光扫描系统稳定性相对较低,不适用于地铁隧道病害检测;而轨道移动式三维激光扫描系统可以根据工点里程距离及数量等特征选取合适的测量设备,结合人工智能算法,移动式三维激光扫描系统的全流程病害识别效率提高约28%。

多尺度人口空间大数据聚合模型在地图可视化中的研究与应用

为解决海量人口和建筑物数据导致的地图渲染时间长、页面卡顿无响应等技术问题,本文提出了一种多尺度人口空间大数据聚合模型,通过研究海量数据逐级嵌套的树型逻辑架构和可视域内的空间关系,实现了超大城市多尺度行政区域的人口空间数据统计分析与可视化,并在多源异构属性融合方面得到了较好的应用,更好地满足了超大城市精细化管理需求。