The 12th China Satellite Navigation Conference S07 Session was Successfully Held
At 08:30 am on May 28, 2021, the 12th China Satellite Navigation Conference S07 Session GNSS Signal Processing was grandly held in Conference Room 308 on the 3rd floor of Primus Hotel Nanchang International Expo City, attracting mnay participating experts and scholars from the industry. The S07 Session focuses closely on the theme of “Spatio-temporal Data, Empowers Birght Future” and mainly deals with four topics: design and realization of new navigation signals, navigation satellite and inter-satellite ranging signal monitoring and evaluation technology, navigation signal reception and processing method and technology, and navigation signal interference detection and anti-interference technology for in-depth exchanegs and discussions.
The conference room was full of people
The Session was opened by the introduction by Shen Jun, CSNC Executive Member. Firstly, Dr. Shen Jun introduced the chairmen of S07 Session in turn and fully affirmed their contributions to the construction of BDS. Next, the First Executive Chairman of S07 Session, Researcher Lu Xiaochun, Director of National Time Service Center of Chinese Academy of Sciences delivered an opening speech on behalf of all the members of the Session. Chairman Lu gave a detailed introduction of the preparations for S07 Session and expressed her expectations for the exchanges during the Session. The lively atmosphere onsite and the heated discussions attracted a large number of audience to the Session. Xie Jun, Chief Designer of BDS-3 navigation satellites and CSNC Executive Chairman, was personally present at the venue throughout the day for on-site guidance. The Session’s popularity endured.
Chairman Xie Jun listening carefully to the report
This Session is honored to invite Zhao Wenjun, Senior Engineer of Beijing Satellite Navigation Center, to give an opening presentation entitled “Preliminary Results of Verification of BDS-3 Short Message Service Applications”. As Chief Engineer of BDS-3 Application Verification, Senior Engineer Zhao Wenjun has participated in the technical research and system development and construction of BDS-1, BDS-2 and BeiDou global system test projects. In his presentation, Mr. Zhao introduced in detail the system composition, function definition, coverage performance and application modes of BDS-3 short message services based on the advantageous and most characteristic short message service of BDS. At present, BDS-3 short message services have been tested in the fields of mobile phones, voice communication and track monitoring, and have been expanded globally. People are all looking forward to the future applications of BDS-3 short message services.
Senior Engineer Zhao Wenjun giving the presentation
Tang Zuping, Associate Professor of School of Electronic Information and Communications, Huazhong University of Science and Technology, delivered the second invited presentation entitled “Low Probability of Intercept Navigation Signal Modulation and its Synchronization Method”. Satellite navigation system provides highly accurate and low-cost spatio-temporal datum for global users, which concerns not only national defense and economic security, but also the convenience of life and safety of life and property of ordinary people. With the increasing reliance of users on satellite navigation, satellite navigation systems need to become more accurate, more available, more reliable and more trustworthy. In his presentation, Mr. Tang introduced the current spread spectrum system for satellite navigation signals, discussed the potential threats to trusted navigation brought by technological development, introduced a new low probability of intercept navigation signal modulation method and its synchronization method for the design of highly trusted satellite navigation signals, and looked forward to prospects for its applications in future navigation signal design.
Associate Professor Tang Zuping giving the presentation
Dr. Yan Tao from Xi'an Branch of China Academy of Space Technology delivered an oral presentation entitled “A Low-complexity Method for Capturing and Tracking CSK Modulated Signals”. Starting from the high data rate required for high-precision positioning, Dr. Yan introduced the high data-rate CSK modulation method and analyzed the problems faced by independent reception of CSK modulated signals. To address the problem, Dr. Yan set out the definition of CSK modulated signals, proposed a method that can independently capture and track CSK modulated signals and verified the effectiveness of the method based on theoretical analysis and simulation. Dr. Yan's proposed method aims to enhance the independence of the received CSK signals and provide thoughts on the improvement of the flexibility of CSK signal design.
Session Chairman Lu Xiaochun presenting a certificate to Dr. Yan Tao
Dr. Zhao Xin from School of Electronic Science, National University of Defense Technology delivered an oral presentation entitled “BOCC: A Binary Offset Carrier Modulation Based on Linear Frequency Modulation Subcarrier”. Traditional GNSS system has low landing energy and limited anti-interference and multipath suppression performance. The LEO satellite navigation augmentation systems feature high landing energy and fast geometric change, and therefore has received wide attention. However, LEO satellite navigation augmentation systems have also brought problems such as signal interferences and signal compatibility issues. The presentation proposed to construct a binary offset linear FM subcarrier modulation (BOCC) by combining the binary linear FM waveform with the spread spectrum code, taking advantage of good anti-interference and time delay resolution performances of linear FM signals. Also, due to the edge peaks in the autocorrelation function of bocc signals, a dual estimation tracking method based on cdll loop was proposed and the usability and effectiveness of the proposed method were verified by Dr. Zhao in all aspects.
Dr, Zhao giving the pesentation
Associate Researcher Wang Ningbo from Aerospace Information Innovation Research Institute of Chinese Academy of Sciences delivered an invited presentation on “BDSMART Space and Atmosphere Integrated Monitoring Equipment: Progress and Experiments”, reporting the latest progress and experiments that the BDSMART team of Chinese Academy of Sciences has made on the space and atmosphere (ionosphere and troposphere) integrated monitoring receiver. By relying on the multi-class and real-time GNSS precision products from the IGS-Chinese Academy of Sciences Ionosphere Analysis Center and Real-Time Analysis Center, the team has developed the BDSMART integrated detection equipment for space and atmosphere environmental parameters by considering multi-frequency and multi-mode GNSS data processing theoretical methods to achieve accurate and reliable detection of parameters related to ionospheric TEC, ionospheric TEC perturbation, ionospheric scintillation and troposphere, which has laid the foundation for the domestically made equipment to realize the networking observation of space, ionospheric and tropospheric information.
Dr. Wang Ningbo giving the presentation
This Session also attracted attention overseas, as Dr. Zixi Liu from Sherman Lo's team at Stanford University was connected to bring us the fourth invited presentation of the Session--“Examining ADS-B Performance in Several GNSS Interference Events to Localize Interference Source”. The presentation discussed the solution of using ADS-B data to detect GNSS interference events: when there is a suspected GNSS interference event in the airspace, one should first accurately determine the presence of the interference event, and secondly, instantly locate the possible location of the interference source. The presentation demonstrated several common features of ADS-B data in interference events, as well as several algorithms for locating the interference source. The presentation brought the Session to a climax again, and several experts and scholars in the civil aviation field had an in-depth communication with Dr. Liu. The Chairman of the Session Researcher Lu Xiaochun, also expressed his care and concern for Dr. Liu who had not returned home for a long time due to the impact of the pandemic.
Live connectioon to Dr. Liu Zixi
In the oral presentation entitled “Research on GNSS Time Series Noise Reduction by Fusing Principal Component Decomposition and Composite Evaluation Index”, Li Xinrui from Chang'an University proposed an adaptive SSA noise reduction method by fusing principal component decomposition and composite evaluation index, in view of the fact that there was no common method to objectively determine the number of optimal reconstruction layers for singular spectrum analysis of noise reduction. Instead of qualitative analysis, the method uses quantitative analysis to accurately determine the number of optimal reconstruction layers. The analysis of simulated and measured GNSS time series data shows that the adaptive SSA can achieve the best ratio of detail information to approximation information, which are negatively correlated, and can be applied in GNSS time series in complex noise.
Li Xinrui giving the presentation
Zhang Weinan, Engineer of Beijing Satellite Navigation Center, brought us an oral presentation entitled “FDMA and CDMA Navigation Signal Compatibility Analysis Methods and GPU Parallel Implementation”, which pointed out that the ITU proposal method was only applicable to CDMA navigation signals, and there was no publicly available compatibility analysis method for FDMA signals internationally. The new concept of frequency division spectral separation coefficient (FD-SSC) and the method of calculating the total interference of FDMA signal sets applicable to FDMA signals were introduced in detail, and the GPU parallel computing implementation plan was introduced based on the characteristics of link calculation in the compatibility analysis, and the performance was analyzed based on experimental results. In the end of the presentation, the application of the compatibility analysis method was demonstrated with the example of interference analysis of BDS and GLONASS in B2/L3 band, and the outlook for the next-step work direction was proposed.
Dr. Zhang Weinan giving the presentation
The opening invited presentation in the afternoon was given by Researcher Chen Jianyun from School of Intelligent Science, National University of Defense Technology and was entitled “Consistent Time-frequency Synchronization Technology for Space-based Distributed Cluster Network”. The presentation was based on the demand for low-cost and high-precision satellite network clock synchronization made by the coordinative application of distributed satellite networks, was focused on introduction of scientific research on the synchronization modeling and mechanism of distributed satellite network clocks, clock, time and frequency measurements and real-time correction methods for highly dynamic satellite networks, clock synchronization control mechanism and control methods for highly dynamic satellite networks and other three aspects. Reseacher Chen also elaborated on his research thoughts on design theories, error models, synchronization mechanisms, correction methods and other key issues related to consistent clock synchronization for highly dynamic distributed satellite networks based on the consistency theory, expanded and enriched the basic theories, methods and technologies related to distributed satellite network clock synchronization.
Researcher Chen Jianyun giving the presentation
Dr. Rao Yongnan, Associate Researcher of National Time Service Center of Chinese Academy of Sciences, gave an invited presentation entitled “Progress of Real-Time Monitoring Technology for GNSS Signal Quality Assessment”, in which Dr. Rao pointed out that the quality of spatial signals was directly related to the ability of satellite navigation system to provide services, and that carrying out signal quality monitoring and assessment to optimize and maintain the performance of satellite navigation signals was an important task in the operation phase of BDS. The presentation introduced the signal quality evaluation results of 24 BDS MEO satellites from the perspective of the actual work of spatial signal quality monitoring and evaluation, and introduced the technical progress of real-time signal quality monitoring in terms of monitoring parameters, monitoring equipment and system implementation. With the input from all parties, the real-time monitoring technology will definitely provide greater support for satellite navigation systems and terminal users.
President Tang Xiaomei presenting a certificate to Dr. Rao Yongnan
In the oral presentation entitled “Joint Spoofing Detection Technology based on Capture Function and Automatic Gain Control", Zhang Tao from Shanghai Jiao Tong University Key Laboratory of BDS Navigation and Location-based Services, addressed the problem of long-distance transmission from satellite to ground, where the receiving power of GNSS signals is very weak and vulnerable to spoofing interference, resulting in abnormal time service/positioning/speed fixing issues. Mr. Zhang used capture function-based monitoring and automatic gain control monitoring as two complementary advantages in spoofing detection, conducted the theoretical analysis of the two methods to obtain their theoretical detection performance, then proposed a joint spoofing detection technology based on capture function and automatic gain control, and conducted experiments to verify the correctness of the theoretical analysis and tested the detection performance of the joint spoofing detection technology.
Zhang Tao giving the presentation
In this session, there are not only wonderful presentations by experts and scholars in the industry, but also the presentation delivered by Chairman of S07 Session Tang Xiaomei, entitled “Overview of Navigation Signal System Certification Technology”. Chairman Tang started with the demand for navigation signal system certification and set out principles and performance evaluation plans for signal system certification on this basis. By considering the many existing certification plans, Chairman Tang gave in-depth thought to the comparison of signal system certification performances and the development trend in the future. The presentation made by Chairman Tang was logical and insightful, in-depth and easy to understand and was well received by all.
Chairman Tang Xiaomei giving the presentation
Senior Engineer Xie Song from State Key Laboratory of Satellite Navigation System and Equipment Technology, the 54th Research Institute of China Electronics Technology Group Corporation delivered a wonderful presentation entitled “Progress of BDS High-performance Navigation and Positioning Technology for Rocket Recovery”, which focused on the problem that the traditional positioning methods could no longer guarantee effective positioning as the rocket booster tended to rotate irregularly during its descent, and it tended to lamd in remote areas, which was unfavorable for search and recovery. Through the comprehensive use of rapid recapture after loss of lock, fast shooting, RN/RD transceiver integration and other technical means to improve the positioning continuity and achieve real-time return of positioning information to support the verification of rocket wreckage recovery technology.
Chairman Li Yang presenting a certificate to Senior Engineer Xie Song
In the presentation entitled “Linear FM Interference Suppression Method Based on Robust Statistical Theory”, Wang Yiming from School of Electronic Information and Automation, Civil Aviation University of China, also Author of Outstanding Paper of the Year of the Session, discussed a GNSS signal processing method for suppressing linear FM interference based on the robust statistical theory, comprehensively analyzed the robustness of the proposed robust method under harsh conditions, and comparatively verified the outstanding advantages of the method under strong interference conditions, which is of guiding importance for the design of interference suppression function in software receivers.
Wang Yiming givin the presentation
Dr. Zhang Ke, Associate Researcher at the Navigation and Space-time Technology Engineering Research Center of National University of Defense Technology, brought us the last oral presentation of the year, entitled “PCMV-based interference suppression technology for dual-polarized antenna array”, which addressed the problem that the global navigation satellite system (GNSS) was susceptible to blockage by broadband RF interference, and the traditional anti-jamming antenna array was ineffective when the incoming waves of the interference and signals were in the same direction. Dr, Zhang proposed the polarization direction map constrained minimum variance criterion (PCMV) based on dual-polarization antenna array, which was able to maintain the reception of the signals while suppressing the interference when the incoming waves of the interference and the signals were in the same direction. Dr. Zhang also proved that when the incoming waves of the interference and signals were in the same direction, PCMV could realize both zero-trap pointed interference and maintain reception of beam-pointing signals when there was variability in the polarization of the signals and the interference.
This Session focused on current hot topics and discussed in particular the application of characteristic BDS-3 short message service and its expanded applications, the design of signal system for special use, the design of signal system for LEO-based integrated navigation and communication, the technologies for monitoring and evaluation of navigation satellites and inter-satellite ranging signals, and the interference detection and anti-interference technologies for navigation signals. Experts and scholars onsite put forward many innovative ideas and technical methods, and gave many constructive opinions or suggestions on navigation satellite signals. The exchange of ideas among experts and scholars greatly promoted the development of GNSS and provided new directions and thoughts for the subsequent development of navigation signal processing.
Group photo of Chairmen of the Session and experts who delivered presentations
