BDSec:Security Authentication Protocol for BeiDou-II Civil Navigation Message

Due to the lack of authentication mechanism in BeiDou navigation satellite system(BDS),BD-II civil navigation message(BDII-CNAV)are vulnerable to spoofing attack and replay attack.To solve this problem,we present a security authentication protocol,called as BDSec,which is designed by using China’s cryptography Shangyong Mima(SM)series algorithms,such as SM2/4/9 and Zu Chongzhi(ZUC)algorithm.In BDSec protocol,both of BDII-CNAV and signature information are encrypted using the SM4 algorithm(Symmetric encryption mechanism).The encrypted result is used as the subject authentication information.BDSec protocol applies SM9 algorithm(Identity-based cryptography mechanism)to protect the integrity of the BDII-CNAV,adopts the SM2 algorithm(Public key cryptosystem)to guarantee the confidentiality of the important session information,and uses the ZUC algorithm(Encryption and integrity algorithm)to verify the integrity of the message authentication serial number and initial information and the information in authentication initialization sub-protocol respectively.The results of the SVO logic reasoning and performance analysis show that BDSec protocol meets security requirements for the dual user identity authentication in BDS and can realize the security authentication of BDII-CNAV.

Data-Driven Heuristic Assisted Memetic Algorithm for Efficient Inter-Satellite Link Scheduling in the BeiDou Navigation Satellite System

Inter-satellite link(ISL)scheduling is required by the BeiDou Navigation Satellite System(BDS)to guarantee the system ranging and communication performance.In the BDS,a great number of ISL scheduling instances must be addressed every day,which will certainly spend a lot of time via normal metaheuristics and hardly meet the quick-response requirements that often occur in real-world applications.To address the dual requirements of normal and quick-response ISL schedulings,a data-driven heuristic assisted memetic algorithm(DHMA)is proposed in this paper,which includes a high-performance memetic algorithm(MA)and a data-driven heuristic.In normal situations,the high-performance MA that hybridizes parallelism,competition,and evolution strategies is performed for high-quality ISL scheduling solutions over time.When in quick-response situations,the data-driven heuristic is performed to quickly schedule high-probability ISLs according to a prediction model,which is trained from the high-quality MA solutions.The main idea of the DHMA is to address normal and quick-response schedulings separately,while high-quality normal scheduling data are trained for quick-response use.In addition,this paper also presents an easy-to-understand ISL scheduling model and its NP-completeness.A seven-day experimental study with 10080 one-minute ISL scheduling instances shows the efficient performance of the DHMA in addressing the ISL scheduling in normal(in 84 hours)and quick-response(in 0.62 hour)situations,which can well meet the dual scheduling requirements in real-world BDS applications.

Design of Space-based PNT System Based on BeiDou Navigation Satellite System

BeiDou navigation satellite system(the BeiDou system) is the only PNT(Positioning, Navigation and Tim-ing) resource in China that has coverage of the globe and near-Earth space and provides continuous high-precision,low-cost positioning, navigation and timing solutions for users in a unified spatio-temporal benchmark. As an importantspatio-temporal benchmark transmission system, the BeiDou system is the most important resource for the nationalPNT system to provide a PNT capability under a unified spatial-temporal benchmark. This paper proposes the con-cept, composition and development model of the space-based PNT system design based on the BeiDou system withall its space characteristics, as well as the advantages of the system. It opens up a new direction for the construction ofChina's PNT system and expands a new horizon in the research of a PNT system in China.

BeiDou Regional Navigation Satellite System Completed

As the 16th BeiDou navigation satellite was successfully launched into space at 23:33 Beijing Time from the Xichang Satellite Launch Center (XSLC) on October 25, 2012, China completed the construction of the BeiDou Regional Navigation Satellite System that starts to officially provide services for most parts of the Asia-Pacific region from December 27. The 16th BeiDou navigation satellite, the last one for the regional BeiDou system, was developed by China Academy of Space Technology under CASC.

China Launches the 11th BeiDou Satellite in Navigation Satellite System

China launched the 11th BeiDou navigation satellite in their BeiDou Navigation Satellite System.The satellite was launched from the Xichang Satellite Launch Center in Sichuan Province on a LM-3C rocket at 0:12 on February 25 (Beijing time) and was put into the predetermined transfer orbit successfully.The geostationary satellite is the first BeiDou navigation satellite launched in 2012 for the

The 10th BeiDou 2 Navigation Satellite Flew into Space

LM launch vehicles established a new record by successfully performing the 16th successful flight this year.A LM-3A launched the 10th BeiDou 2 satellite into its predetermined transfer orbit on December 2 from the XSLC in Sichuan Province.

Networking of BeiDou Navigation Satellite System Accelerated with Two New Members

At 4:50 on April 30, China's LM-3B/I rocket, an improved type based on LM-3B, made its debut at the Xichang Satellite Launch Center and successfully sending the 12th and 13th BeiDou Navigation Satellite System satellites into the planned transfer orbit in space. It was the first time that China launched two BeiDou satellites with one rocket. It was

New Regional Satellite Positioning Constellation Scheme Discussion

The characteristics of present “Beidou” satellite positioning system are analyzed. In order to perfect our country regional satellite positioning system, the idea of “Beidou” geosychronous earth orbit （GEO） satellites combined with some middle earth orbit （MEO） satellites constellation is put forward. The details of general satellite constellation optimized method are described, using this method the multiple positioning constellation design results are gained. And those results belong to two type of sehems, one is 2 GEO plus some MEO satellites and the other is 3 GEO plus some MEO satellites. Through simulation and comparison, among those multiple design results, final optimized regional positioning constellation is given. In order to check the chosen constellation cover performance, the position dilution of preeision（PDOP） is calculated, and with ,satellite constellation simulation software Satlab many coverage performances of the chosen constellation substellar point track, elevation, azimuth and visible satellites number changing situation are also simulated.

A Dual-Satellite GNSS Positioning Algorithm of High Accuracy in Incomplete Condition

Global navigation satellite system could provide accurate positioning results in signal complete condition. However, the performance is severe when signal denied, especially for the single-mode Bei Dou receiver. This paper proposes a dual-satellite positioning algorithm to promote the positioning performance in the satellite signal gap. The new algorithm utilizes the previous positioning data stored in complete condition to simplify the positioning equations. As the clock bias persists for a short period, this proposed method could work out accurate positioning results by only two visible satellites, without the need of computing the clock bias. Also, the Kalman filtering algorithm is used to smooth the trajectories, and improve the positioning results. During the incomplete period, only two satellites for 30 seconds and three satellites for 60 seconds, the preliminary experiment result shows that, the presented method could provide almost the same positioning results as in complete condition.

广播星历旋转误差对低轨星载BDS-3/GPS实时精密定轨影响分析

基于LT-01A卫星星载BDS-3/GPS观测值进行了星载实时精密定轨研究,并重点分析了广播星历旋转误差对实时定轨精度的影响。通过赫尔默特转换评估了所选时段内GPS和BDS-3广播星历轨道旋转误差,显示BDS-3广播星历旋转误差可达-8.7 mas,平均量级较GPS大约2.5倍。BDS-3广播星历经旋转改正后,轨道切向、法向均方根(RMS)误差从25 cm左右提升至10 cm量级,提升幅度超过50%。因此,基于星载BDS-3以及BDS-3/GPS联合的实时定轨精度受BDS-3星历旋转误差影响严重,且主要作用于切向和法向。经过旋转改正后,单独BDS-3实时定轨在切向、法向、径向RMS分别为21.0 cm、10.7 cm及11.2 cm,其切向和法向精度比改正前分别提升15.0%和31.8%;BDS-3与GPS联合定轨进一步提升切向精度至19.4 cm。得益于BDS-3广播星历较高的精度,单BDS-3以及BDS-3/GPS联合的实时定轨在旋转改正前的三维RMS分别为31.9 cm和29.2 cm,较单GPS实时定轨分别提升9.1%和16.8%;添加旋转改正后,其定轨精度分别提升至26.7 cm和25.0 cm,较单GPS实时定轨分别提升22.6%和27.5%。

北斗全球卫星导航系统工程技术与管理创新

北斗全球卫星导航系统由中国自主建设运行,具备向全球用户提供全天时、全天候、高精度定位、导航和授时服务能力,具有报文通信、国际搜救等功能。北斗全球卫星导航系统坚持“自主、开放、兼容、渐进”的发展原则,发挥新型举国体制优势,全面突破核心关键技术,创新发展工程管理模式,实现了国际卫星导航领域和我国航天领域的多个首创,提前半年完成建设,走出了一条符合我国国情、独具特色的国家超级工程发展道路。本文围绕北斗全球卫星导航系统任务要求,全面阐述工程任务组成、任务进程和系统应用,从“混合星座、通信导航融合、星间链路、导航信号、快速组网、核心产品国产化”等方面梳理系统技术特点与创新,并总结了北斗工程建设过程中组织、技术、进度、质量和运行服务等管理体系的创新举措。

基于Hatch滤波的改进矩阵变换法在BDS多频模糊度解算中的应用

长基线条件下,空间相关性弱,电离层延迟残差和噪声影响变大,致使矩阵变换法模糊度解算过程中,窄巷组合受噪声影响大,单历元模糊度解算成功率低。因此,削弱电离层残差及噪声影响可以一定程度提高模糊度解算成功率。本文在分析矩阵变换算法基础上,利用Hatch滤波有效抑制伪距测量噪声和多径效应特点,结合弱电离层、低噪声的载波组合,通过相位平滑伪距代替组合伪距值参与解算,从而削弱电离层残差及观测噪声影响。通过实测数据分析,本文算法可有效提高矩阵变换法模糊度解算成功率。

北斗导航卫星系统在水利行业的应用与展望

北斗导航卫星系统是我国重要的时空基础设施,建设以来已经广泛应用于社会经济多个领域。智慧水利是新阶段水利高质量发展的最显著标志和6条实施路径之一,北斗导航卫星系统为智慧水利提供了强大的技术支撑,为数字孪生水利建设提供了重要的时空基准和高精度的位置及通信服务。从北斗导航卫星系统的功能视角,选择水利工程变形监测、水利巡检、水文监测数据传输等典型应用场景,分析了北斗导航卫星系统的应用现状;同时,还讨论了北斗遥感技术在水位监测、土壤水分反演和大气水汽反演等方面的应用情况;最后,展望了北斗系统在水利领域的发展趋势,指出其应用场景和领域将持续拓展、应用规模将不断增长,以及与新技术融合应用将不断增强,随着北斗导航卫星系统技术的持续创新和应用范围的进一步扩大,北斗导航卫星系统在未来水利行业中将发挥越来越重要的作用,它将成为加快水利新质生产力、推动水利高质量发展的重要推力。

基于铁路带状北斗CORS的网络RTK测量精度分析

为研究和拓展北斗导航系统在铁路工程测量中的应用,利用BDS系统技术优势解决山区铁路测量定位难题。基于某山区铁路建立带状北斗连续运行参考站系统(以下简称“北斗CORS系统”)和高精度位置服务云平台。采用国产多星多频测量型接收机进行控制点数据采集工作,分别对比基于北斗CORS系统的单BDS、单GPS以及GNSS混合星历网络RTK观测数据以及传统基站形式的RTK观测数据的测量精度。结果表明:(1)铁路带状北斗高精度位置服务云平台网络RTK定位功能稳定可靠;(2)基于北斗CORS系统的网络RTK测量方法仅需进行高程曲面拟合,按3s采集的成果精度即可满足铁路测量规范中网络RTK中线测量、断面测量、施工放样、像控测量的精度要求,测量时应尽量采用同类型的设备并采用同精度观测方法以保证重复测量精度,也可通过增加观测时长、在局部区域利用既有高程控制点做高程校正的方式提高测量精度;(3)基于北斗CORS系统的网络RTK测量平面和高程内符合精度限差可分别设定为1.7 cm和2 cm,外符合精度可分别设定为2.2 cm和5 cm。

北斗三号系统PPP-RTK技术在车辆自动驾驶应用可行性研究

卫星导航定位技术是支撑车辆自动驾驶的关键技术,北斗三号全球卫星导航系统建成开通,使得基于北斗三号系统的PPP-RTK技术具备了各行各业广泛应用的基础。本文从PPP-RTK技术本身的发展和车辆定位系统等方面开展论述,对PPP-RTK技术在车辆自动驾驶中应用的可能性进行探究。

Advances in BeiDou Navigation Satellite System(BDS)and satellite navigation augmentation technologies

Several noteworthy breakthroughs have been made with the BeiDou Navigation Satellite System(BDS)and other global navigation satellite systems as well as the associated augmentation systems,such as the commissioning of the BDS-3 preliminary system and the successful launch of the first BDS-3 GEO satellite which carries the satellite-based augmentation payload.Presently,BDS can provide basic services globally,and its augmentation system is also being tested.This paper gives an overview of BDS and satellite navigation augmentation technologies.This overview is divided into four parts,which include the system segment technologies,satellite segment technologies,propagation segment technologies,and user segment technologies.In each part,these technologies are described from the perspectives of preliminary information,research progress,and summary.Moreover,the significance and progress of the BeiDou Satellite-based Augmentation System(BDSBAS),low earth orbit augmentation,and the national BeiDou ground-based augmentation system are presented,along with the airborne-based augmentation system.Furthermore,the conclusions and discussions covering popular topics for research,frontiers in research and development,achievements,and suggestions are listed for future research.

Preliminary assessment of the navigation and positioning performance of BeiDou regional navigation satellite system

BeiDou regional navigation satellite system(BDS)also called BeiDou-2 has been in full operation since December 27,2012.It consists of 14 satellites,including 5 satellites in Geostationary Orbit(GEO),5 satellites in Inclined Geosynchronous Orbit(IGSO),and 4 satellites in Medium Earth Orbit(MEO).In this paper,its basic navigation and positioning performance are evaluated preliminarily by the real data collected in Beijing,including satellite visibility,Position Dilution of Precision(PDOP)value,the precision of code and carrier phase measurements,the accuracy of single point positioning and differential positioning and ambiguity resolution(AR)performance,which are also compared with those of GPS.It is shown that the precision of BDS code and carrier phase measurements are about 33 cm and 2 mm,respectively,which are comparable to those of GPS,and the accuracy of BDS single point positioning has satisfied the design requirement.The real-time kinematic positioning is also feasible by BDS alone in the opening condition,since its fixed rate and reliability of single-epoch dual-frequency AR is comparable to those of GPS.The accuracy of BDS carrier phase differential positioning is better than 1 cm for a very short baseline of 4.2 m and 3 cm for a short baseline of 8.2 km,which is on the same level with that of GPS.For the combined BDS and GPS,the fixed rate and reliability of single-epoch AR and the positioning accuracy are improved significantly.The accuracy of BDS/GPS carrier phase differential positioning is about 35 and 20%better than that of GPS for two short baseline tests in this study.The accuracy of BDS code differential positioning is better than 2.5 m.However it is worse than that of GPS,which may result from large code multipath errors of BDS GEO satellite measurements.

Initial analysis for characterizing and mitigating the pseudorange biases of BeiDou navigation satellite system

Pseudorange bias has become a practical obstacle in the field of high-precision global navigation satellite system(GNSS)applications,which greatly restricts the further development of high-precision applications.Unfortunately,no studies have been conducted on the pseudorange biases of the BeiDou navigation satellite system(BDS).To mitigate the effects of pseudorange biases on the BDS performance to the greatest extent possible,the origin of such BDS pseudorange biases are first thoroughly illustrated,based upon which the dependency of the biases on the receiver configurations are studied in detail.Owing to the limitations regarding the parameter re-settings for hardware receivers,software receiver technology was used to achieve the ergodicity of the receiver parameters,such as the correlator spacing and front-end bandwidth,using high-fidelity signal observations collected by a 40-m-high gain dish antenna at Haoping Observatory.Based on this,the pseudorange biases of the BDS B1I and B3I signals and their dependency on different correlator spacings and front-end bandwidths were adequately provided.Finally,herein,the suggested settings of the correlator spacing and front-end bandwidth for BDS receivers are in detail proposed for the first time.As a result,the pseudorange biases of the BDS signals will be less than 20 cm,reaching even under 10 cm,under this condition.This study will provide special attention to GNSS pseudorange biases,and will significantly promote a clear definition of the appropriate receiver parameter settings in the interface control documents of BDS and other individual satellite systems.

Global precision analysis of carrier phase relative positioning in BeiDou navigation satellite system and United States global positioning system

In this paper, we derived a high-efficiency formula for calculating the precision of carrier phase relative positioning,analyzed the various factors that affect the positioning accuracy using the carrier phase, and proposed the concept of using a frequency dilution of precision to describe the quantitative effect of different frequency combinations on the positioning precision. To this end, we computed and plotted the global spatial distribution map of the relative positioning dilution of precision for single-day solution, half-hour solution, and single-epoch solution of the global positioning system(GPS), regional Beidou navigation satellite system(BDS2), future global Beidou navigation satellite system(BDS3), and their fusion systems.Using processing software with autonomous intellectual property rights(GCN and VENUS/ARSNet), we solved the measurement data and examined the positioning precision of the single-day solution and single-epoch solution of GPS and BDS2.The analysis demonstrated that the B1/B2 frequency positioning precision of BDS2 was better than that of L1/L2 frequency positioning of GPS, but the positioning precision of the BDS2 is worse than that of GPS over most of the service region of the BDS2. Further, the positioning precision of BDS3 is better than that of GPS in the Asia-Pacific region, while it is the opposite in other regions. Based on these conclusions, we put forth some optimization recommendations regarding the signal frequency of the navigation system and GPS measurement standards to serve as references for optimizing the system performance and formulating standards.

北斗三号系统卫星自主完好性监测技术

完好性对于全球卫星导航系统(GNSS)来说至关重要,关乎到其能否被放心应用。卫星自主完好性监测(SAIM)技术,是完好性监测技术发展的前沿趋势,国内外卫星导航系统均竞相发展。介绍了北斗三号系统SAIM技术设计与实现的重要意义,从功能设计和实现原理两个方面,阐述了北斗三号SAIM技术体制。针对SAIM实际在轨监测数据的正态分布特性服从程度和长期稳定性等问题,随机选取某一颗中圆轨道(MEO)卫星自2020年7月31日北斗三号系统正式开通服务以来至2021年7月31日连续1年期间的监测数据,得到真实在轨监测数据的分布特性。最后,提出了告警门限优化、分级告警策略设计、星历完好性自主监测等方面的后续发展必要性建议,旨在为北斗系统更好地为全球用户提供更优质的完好性服务提供参考。