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China Satellite Navigation Conference (CSNC) 2015 Proceedings presents selected research papers from CSNC2015, held during 13th-15th May in Xian, China. The theme of CSNC2015 is Opening-up, Connectivity and Win-win. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 10 topics to match the corresponding sessions in CSNC2015, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

SUN Jiadong is the Chief Designer of the Compass/ BDS, and the academician of Chinese Academy of Sciences (CAS); LIU Jingnan is a professor at Wuhan University. FAN Shiwei is a researcher at China Satellite Navigation Office; LU Xiaochun is an academician of Chinese Academy of Sciences (CAS).



BDS/GNSS Navigation Applications


Chapter 1. Accuracy Assessment of the Doppler Frequency and Pseudorange Model Based on GPS/LEO Radio Occultation

The Doppler frequency and pseudorange model are important information for open-loop tracking of GPS/LEO signal. The Doppler frequency model can be predicted through iteration, with the use of a bending angle/refractivity climatology and satellite orbits. The pseudorange model can be obtained by multi-epoch or single-epoch algorithm. About 7279 COSMIC radio occultation soundings, from DOY (day of year) 71 to DOY 73 in 2007, recorded in open-loop mode are processed by above-mentioned algorithms, the calculated Doppler frequency and pseudorange model are compared with corresponding COSMIC observations. The statistical comparisons of the difference between COSMIC Doppler frequency observation and Doppler frequency model show: above 2 km impact height, the mean Doppler frequency shift caused by the Earth’s neutral atmospheric condition is less than 3 Hz, the corresponding standard deviation is less than 6 Hz. The mean and standard deviation of the difference between COSMIC phase observation and pseudorange model calculated by multi-epoch algorithm are less than 15 m and 23 m, respectively, above 2 km. Similar results can be found in the single-epoch algorithm. The accuracy of the pseudorange model calculated by single-epoch algorithm is better than that of multi-epoch algorithm. Therefore, the atmospheric Doppler and pseudorange model predicted by the single-epoch algorithm can be used to track the GPS radio occultation signals recorded in the open-loop mode.

Xian-Sheng Xu, Yan Liu, Ye Li, Xu Xu

Chapter 2. Application of BeiDou Navigation Satellite System on Attitude Determination for Chinese Space Station

BeiDou Navigation Satellite System (BDS) offers service to space-based users. The future Chinese Manned Space Station (CSS) orbits inside the service area of the future global BDS, and can utilize BDS to perform its attitude determination. This contribution first analyzes the constellation situation of the global BDS during the operation phase of the CSS. The results show that the global BDS can provide positioning and attitude determination service to the CSS. Second, the principles of the carrier phase based attitude determination technique are presented and the characteristics of the CSS are discussed, based on which the technical conditions required for BDS-based attitude determination for the CSS are analyzed. An attitude determination scheme which requires three antennas to be installed on the three CSS’ component cabins respectively is proposed. Next, simulations and analysis on the roll, pitch and yaw angle measurement errors when the CSS is orbiting are conducted. The results indicate the feasibility of applying BDS on the attitude determination for the CSS, and the root mean square errors of the measured attitude angles can reach about 0.05° for roll and pitch, and 0.04° for yaw respectively, provided the condition of two linearly independent 10 m level baselines formed by three BDS receiving antennas.

Sihao Zhao, Cai Huang, Xin Qi, Mingquan Lu

Chapter 3. Feasibility Analysis of High-Precision Deformation Monitoring Using BeiDou Navigation Satellite System

Since the launch of the last GEO satellite on December 27, 2012, BeiDou regional navigation satellite system (BDS) has been announced to provide positioning, navigation, timing (PNT) and short message communication services in the whole Asia-Pacific region, which suggests a new GNSS system could be applied for deformation monitoring in the future. In order to investigate the performance of BDS in high-precision deformation monitoring, an experiment platform was designed where the actual displacements could be defined accurately as the reference and a corresponding BDS data processing software was developed. With the platform, data over 15 days were obtained and were processed every 4 h for evaluating the precision and reliability of deformation monitoring using BDS only. The results show that, for short baselines the repeatability of the horizontal and vertical directions are better than 1 and 2 mm, respectively. In addition, the comparison of deformations calculated from the BDS data and the reference displacements derived by the experiment platform confirms a good agreement, which indicates the potential of BDS for deformation monitoring applications.

Ruijie Xi, Yugang Xiao, Xingwei Liu, Kaihua Wang

Chapter 4. Analysis on Velocity Measurement Precision of High Dynamic GPS Receiver Carrier Tracking Loop

The dissertation introduced factor that high dynamic condition influence the velocity measurement precision of GPS receiver’s carrier tracking loop. Based on analyses on the measurement error and tracking threshold, the adaptability and tracking precision of carrier tracking loop in high dynamic condition were simulated, the measurement error and the finally velocity precision were expressed in different high dynamic condition. The paper has important theoretical significance for comprehending the velocity measurement precision in high dynamic condition and designing tracking loop that is adapted to high dynamic condition.

Xudong Liu, Guangjun Liu, Qiang Li, Haiying Luo

Chapter 5. Theoretical Study of Bare Soil Parameters’ Effects on GPS Multipath Observables

In the past two decades, GNSS-R has emerged as a new and attractive remote sensing technique. The geodetic/geophysical GPS receivers are out-of commercial and their recorded multipath observables have potentials for geophysical parameters detections, e.g. soil moisture, vegetation growth and snow depth. Based on the developed forward GPS multipath model, effects of bare soil parameters on GPS multipath observations are evaluated here. Wave synthesis technique is employed to get the coherent scattering coefficients at VV, HH, RR and LR polarizations, while the bare soil dielectric constant is calculated by a microwave dielectric soil-water mixing model. Effects of three-frequencies GPS modulations (L1 band, L2 band and L5 band) are evaluated: although there are apparent differences for GPS multipath observables, it is not the effects of bare soil but the direct broadcasting signals since soil scattering properties at these frequencies (L band) are the same. Soil texture and surface roughness have almost no effects on GPS observables. As the soil temperature changes from SubZero to above zero, the amplitudes of SNR, phase and code pseudorange increased. Soil moisture also affects GPS observables, as moisture content increases, the amplitudes of GPS observables increase.

Xuerui Wu, Shuanggen Jin, Ye Li

Chapter 6. Satellite-Ground TT&C United Scheduling Methods of GNSS Constellation Based on Nodes Constraint

In this paper, targeting at the effective management of TT&C and communication system of GNSS constellation, we analyze the constraint demands of TT&C and communication scheduling from the part of autonomous navigation precision, information transmission delay and integrality. Then, the model of node satellite selection is established which satisfy the optimized aims of multi-satellite tracking and exclusive satellite-ground link constraint satisfaction. Furthermore, the improved genetic algorithm is designed, which is used to scheduled satellite-ground resources. The results show that the strategy and algorithm are improved compared with traditional method.

Li Jing, Zhang Tianjiao, Ye Gangqiang

Chapter 7. Realization of Real Time Kinematic Positioning Software Based on Kalman Filter

As an important optimization estimation theory, Kalman filter is applied to deal with many kinds of dynamic data, especially for GPS data and inertial navigation data. In this paper, the Kalman filter is used to solve the two key problems-integer ambiguity calculation and cycle slip detection and correction, and then a real time kinematic (RTK) positioning technique based on Kalman filter is proposed. The experimental results show that the presented method can obtain the positioning accuracy of RTK up to centimeter for data format in GPS.

Dangwei Wang, Yi Lai

Chapter 8. Analysis of BeiDou Satellite Orbit Prediction Based on ERP Prediction Errors Impact

According to the real-time positioning of BeiDou navigation satellite. Analysis Center (AC) was necessary to develop Earth Rotation Parameters (ERP) products based on autoregressive integrated moving average (ARIMA) mode, then, it necessary to transform the BeiDou navigation satellite ephemeris of Inertial System to the Earth Solid System according to the ERP prediction products. For MEO, IGSO and GEO, the development of ERP products of AC calculated the BeiDou navigation satellite orbit error was less than 50 cm based on the ERP product of Earth Rotation Service System (IERS) forecast for 30 days in the Earth Solid System orbit as a true value, which indicated that the ERP prediction error impacted the Earth Solid System precise ephemeris calculation accuracy, and indicated AC ERP prediction results with IERS products fairly.

Xiusong Ye, Hai Guo, Jie Yang, Chao Li, Canyou Liu

Chapter 9. The Repeatability Test of BDS Baseline Processing

BeiDou Navigation System (BDS) has already covered all areas in our country. Getting high precision positioning results becomes hot topic in the research of BDS. This paper calculates parts of BDS baseline observation data from Hebei Province, and the results indicate the BDS system is stable, the external compliance precision of plane is within 1 cm, and the precision of elevation is about 4 cm, meeting the requirements of the precision of the control network of national grade B, the differences of precision for the same baseline results is limited in 5 mm, and the unit weight variance value and RMS error precision indicators also meet the specification requirements.

Yanguo Liu, Jinzhong Bei, Dehai Li, Hu Wang, Xiaying Wang

Chapter 10. A System Developed for Monitoring and Analyzing Dynamic Changes of GNSS Precipitable Water Vapor and Its Application

Water vapor is an important factor to the formation of small and medium-scale disastrous weather. Its temporal and spatial variation is extremely violent and uneven in the air. Therefore, the development of a real-time monitoring and analysis system for dynamic variations characteristics of spatial and temporal water vapor has great practical significance and application value to short-impending rainstorm forecast. The GNSS/PWV dynamic changes monitoring and analysis system was built on the Matlab platform. Based on the calculated PWV of every CORS reference station, it can be used to demonstrate the time series analysis and planar dynamic changes of various kinds of meteorological elements (PWV, temperature, barometric pressure and relative humidity, etc.). Especially, it can accurately reflect one and two dimensional dynamic trends of the water vapor within the CORS coverage area, track the dynamic changes of atmospheric water vapor content and enhance the monitoring and forecasting capabilities of meteorological departments for small and medium scale disastrous weather.

Li Li, Zhimin Yuan, Ping Luo, Jun Shen, Sichun Long, Liya Zhang, Zongli Jiang

Chapter 11. Multifunctional Satellite Navigation and Communication Mast Antenna Based on Mobile Platform

The paper is mainly about one kind of communication antenna based on civilian vehicles, which can meet the requirement of satellite navigation, communication. The paper focuses on the analysis of the technology of a broadband UHF quadrifilar helix antenna. Also the paper explores the implementation method of broadband quadrifilar helix antennas by theoretical research and electromagnetic model analysis. We achieve the goal that VSWR is less than 3 from f1 to 2.5f1. Experimental results and simulation results match better and we get the expected radiation characteristic. The cascade connection of multi-band frequency and different function antennas has been achieved. The study of the paper has significance for implementation of the technology of civilian communication vehicles and rescue vehicles.

Jia Zhang, Ximing Liang, Haiguang Zhang

Chapter 12. Optimal Satellite Selecting Algorithm in GPS/BDS Navigation System and Its Implementation

As the Global Navigation Satellite System (GNSS) steps into a new era of multiple constellations, multiple constellations bring opportunities for navigation and positioning services. Under the condition of the existence of multiple constellations, the number of observable satellite number will increase sharply in single epoch. Because of the limitation of computing source, too much redundant information brought by redundant satellites can not greatly improve the accuracy of positioning, however, it may actually increase the computational burden of receiver. Therefore, optimizing the satellite selection algorithm is of great significance. Based on the relations of constellation’s geometry and the principle of GDOP, this paper proposed a satellite selection algorithm suitable for multiple constellations. Furthermore, a satellite selection strategy applied to 5–7 satellites is considered. The experimental results show that on the premise of positioning accuracy, the improved satellite selection satellite can significantly reduce the calculation time and has good real-time performance and reliability.

Zhuoxi Ma, Li Yang, Xiaolin Jia, Dan Zhang, Shuai Liu

Chapter 13. An Improved Method to Accelerate the Convergence of PPP-RTK with Sparse CORS Stations’ Augmentation

Real-time kinematic Precise Point Positioning (PPP-RTK) with dense regional reference stations’ augmentation has been proved to be effective for rapid precise positioning. However, with increasing distance between the rover and the reference receivers, the decorrelation of the atmospheric errors will make it more and more difficult to fix the ambiguities quickly. Recent studies show that PPP using the raw observables by estimating the ionospheric and tropospheric delays not only can improve the convergence of PPP but also can overcome the re-initialization of PPP, however the correlations between the atmospheric delays and the ambiguities will cause the wrong fixing of the ambiguities, which will introduce biases in the coordinates. In this contribution, in order to achieve fast precise positioning augmented with sparse continuously operating reference stations (CORS), PPP with raw observables are used as basic observations, the L1/L2 ambiguities are estimated firstly, then the wide-lane and narrow-lane ambiguities are formed, and the wide-lane and narrow-lane ambiguities are fixed recursively. In this new method, the narrow-lane ambiguities are free from ionospheric delays, so the correct fixing can be guaranteed, meanwhile the re-initialization can also be overcame. To evaluate the proposed strategy, four rover stations with average distance of 33 km within a sparse reference network, the average distance of which is about 200 km, are chosen to test the positioning performance. The simulated results show that the wide-lane ambiguities can be fixed immediately, and the narrow-lane ambiguities can be fixed quickly, usually at 3–30 epochs, and after ambiguity fixing, the positioning accuracy can achieve at cm-level.

Shoujian Zhang, Jiancheng Li, Lei Zhao

Chapter 14. Research on GEO Satellite Global Monitoring and Control Based on BeiDou Navigation Satellite System

GEO satellite global monitoring and control refers to the real-time monitoring and control communication for the target satellite in the geostationary orbit through the TT&C system. Due to the presence of invisible arc between the domestic ground station and certain GEO satellite, it’s need the help of space-based monitoring and control system or other system with space communication capability to relay forwarding, in order to achieve the real-time communication between the target satellite and the domestic control center. Through the analysis of GEO satellite global mission supporting of current space-based monitoring and control system, it is found that BeiDou Navigation Satellite System (BDS) can be applied to achieve the real-time monitoring and control mission for the domestic control center and overseas GEO satellites. In this paper, the GEO satellite monitoring problem and mission requirements are systematically analyzed combined with the national TT&C network developing status and future plans. According to its composition and mission support capabilities, GEO satellite global monitoring and control communication process is described in support of BDS. Then, the feasible schemes are designed from the geostationary, inclined and medium constellation of BDS. Finally, the recommendation and conclusion of GEO satellite global mission planning based on BDS are given.

Yue Zhao, Xianqing Yi, Zhenwei Hou, Tao Zhong

Chapter 15. The Optimal Distribution Strategy of BeiDou Monitoring Stations for GEO Precise Orbit Determination

The accuracy of BeiDou GEO satellites precise orbit determination is poor. In addition to high altitude and constant position, the monitoring stations distribution is also an important factor of GEO satellites orbit determination. Firstly, the basic principle of geometry orbit determination is introduced and the observation equation is linearized in this paper. Secondly, The GDOP value is parameterized by using orthogonal trigonometric functions. Thirdly, the relationship between stations distribution and the accuracy of precise orbit determination is analyzed according to nested cones. Finally, the simulation experiments are carried out, and a kind of the optimal solution is concluded.

Longping Zhang, Yamin Dang, Shuqiang Xue, Hu Wang, Shouzhou Gu, Chuanyang Wang

Chapter 16. Analysis and Comparison of Non-coherent and Differential Acquisition Integration Strategies

In the application of global satellite position system, signal adaptive acquisition strategies are required for various environment applications, such as weak signal, emergency moment, so fast and high sensitivity acquisition algorithms are important for the receiver process. This paper presents acquisition algorithms: coherent integration, non-coherent integration, differential coherent and differential non-coherent integration, and the differential integration are analyzed in both standard and pair-wise form, all of which are theoretically compared in their probability distribution with detailed analysis. And testing statics using Monte-Carlo with collected realistic various signal, considering the existence of carrier Doppler frequency and code phase shift in the objectives, give out that in certain probability of detection, differential standard coherent integration is the best detector, non-coherent integration is the second best; and differential pair-wise coherent, differential standard and pair-wise non-coherent integration give out almost the same performance; and the standard algorithm is more tolerable in residual Doppler environment than the pair-wise algorithm; the code phase shift will affect much more in the lower probability of detection; finally, in the theory analysis, the hypothesis of approximated gauss distribution and the IQ data completely independence with each other need to be revised in more accurate model to fit the actual data.

Dandan Zeng, Songlin Ou, Jinhai Li, Jinhai Sun, Yuepeng Yan, Haofeng Li

Chapter 17. A New Method Based on QSE Processing for Interferometric GNSS-R Ocean Altimetry

Considering that in conventional GNSS-R (Global Navigation Satellite System-Reflection) altimetry, the reflected signals are cross-correlated with a locally generated clean replica of the transmitted signal, interferometric processing consists of the measurement of the complex cross-correlation between the direct and reflected signals. It allows the exploitation of P(Y) code and other civil signals to maximize the height estimation precision. This paper presents a new processing method called QSE (Quadrature Staggered Extracting) which utilizes P(Y) code to explore a further improvement of the altimetry precision. The assessment of the QSE processing procedure illustrates GPS L1 band as an example. In these conditions, this paper analysis the up-looking SNRs obtained by using QSE processing and traditional coherent demodulation respectively. The analysis of the altimetry precision shows that the results obtained by adopting QSE processing improve by a factor about 1.15 as compared to the results obtained by using coherent demodulation.

Chenghui Yu, Chundi Xiu, Weiqiang Li, Dongkai Yang

Chapter 18. Analysis of GNSS Signals with Application to Lunar Navigation

GNSS-based navigation technology for lunar mission with more than 60,000 km above earth, which is still lack of relevant research and simulation. In this paper, “Chang-E One” lunar mission is used with three stages of orbiting the earth, earth-moon transfer, and around moon. A detailed analysis of feasibility of autonomous navigation using GPS, GALILEO navigation system alone and combination under sidelobe signals is given. The number of visible satellites GNSS receiver to receive, DOP value, receiving signal level and dynamic, etc. are analyzed, and autonomous navigation algorithm design under different observation conditions were also considered. As can be seen from the theoretical analysis and simulation results, the use of GNSS signals fully meet user needs that realize autonomous navigation around earth, earth-moon transfer, and around moon three-stages, which can be considered as the foundation for future engineering applications.

Xiaoliang Wang, Longlong Li, Xingyuan Han, Yansong Meng, Lin Wu

Chapter 19. Experiment and Result of Precise Kinematic Orbit Determination for LEO Satellite

Function for LEO kinematic orbit determination was developed and integrated into the SPODS software, which has been designed and developed at Xi’an Research Institute of Surveying and Mapping. This paper presents briefly the principle and method adopted such as observation model, error correction and parameter estimation. Since there are so many epoch-related unknown parameters, the position coordinates and clock offset of onboard receiver, an approach of Least-Square method with parameter pre-eliminating is employed for parameter estimation in data processing. A set of GPS data of GRACE-A/B during Sept. 01–09 2012 was collected and experiments were carried out to evaluate the performance. The result exhibits that, by comparing with the post precise orbit product (GNV1B) from JPL, the accuracy for R component is 0.03–0.05 m, while for T and N components are 0.02–0.04 m.

Rengui Ruan, Laiping Feng, Xianbing Wu

Chapter 20. A GNSS Anti-spoofing Method Based on the Cooperation of Multiple Techniques

An anti-spoofing technique based on the cooperation of multiple detections is proposed in this paper. A GNSS receiver could detect more than one correlation peak in one processing channel in acquisition when the spoofing signal exists. Signal quality monitoring (SQM) can detect abnormal changes of the correlation peak when spoofing attack on tracking receiver. Generally, receiver gives up the measurements of the abnormal channel to avoid the risk of tracking fault or spoofing signal. This decreases the number of available signals. Receiver autonomous integrity monitoring (RAIM) is capable of detecting and mitigating single error but lack of dealing with multiple errors. This paper proposes a cooperation method of these three techniques which are complementary. Detailed discussion of the method’s procedure and performance are provided in this paper. Simulation results demonstrate that the method is feasible and effective to detect and mitigate multiple spoofing signals.

Huiqi Tao, Hong Li, Mingquan Lu

Chapter 21. Based on Singular Spectrum Analysis in the Study of GPS Time Series Analysis

In this paper, using the singular spectrum analysis (SSA) method for analysis of IGS station of ARTU time series was studied. The SSA-IQR (Singular Spectrum Analysis-Inter Quartile Range) is used to detect gross error. Using the method of singular spectrum iteration to fill the gaps of missing datas. This methods can achieve high precision. Singular spectrum analysis method can extract informations effectively to complete the recognition and extraction of trend and cycle item, and it can eliminate noise effectively, to smooth the effect. Experiments show that: ARTU station have trends obviously. Especially the linear trend term. By using the least square fitting the linear trend. Periodic cycle components exist in a variety of parallel.

Ronghai Qiu, Yingyan Cheng, Hu Wang, Xiaoming Wang

Chapter 22. Initial Performance Assessment of BDS Real-Time Relative Positioning with Triple-Frequency Observations

Corresponding theoretical research has concluded that applying triple-frequency observation could performance of strength of equation system and improve the reliability of positioning result. Currently, BDS transmits navigation signal on three frequencies which enable the performance assessment of BDS using real triple-frequency observation. The characteristic of BDS triple-frequency observation is analyzed in respect of signal strength, multipath level and inter-frequency delay. Moreover, performance of BDS single-epoch relative positioning over different baseline length is assessed with real observation. The experiment results demonstrate that the fixed rate of triple-frequency ambiguity resolution is higher than dual-frequency case. It has also been concluded that application of triple-frequency observations has advantages over dual-frequency solution on reliability of fixed solution and decreased number of incorrectly fixed epoch.

Min Wang, Hongzhou Cai, Jun Liu, Anmin Zeng

Chapter 23. Unified Estimation Model of Multi-system Biases Including BDS/GPS/GLONASS/Galileo

Beidou Navigation Satellite System (BDS) will increase the numbers of available observations to improve the solution accuracy, reliability and availability of precise positioning. Multi-system fusion with BDS is nowadays increasingly paid attention. However, the multi-system fusion focuses only on loose combination model, which means that each system has their reference satellite each other. This model will increase the probability of initialization because the reference satellite can be often changed during the process of positioning. If multi-system fusion has unified time and signal reference, that is, multi-system fusion selects the same satellite as the reference satellite, the problem will be covered. Therefore, the paper proposed an estimation model of multi-system biases for multi-system fusion. The estimation model will investigate differential code bias (DCB) of each system and inter-system biases (ISB) among systems. Multi-system data from IGS, MGEX and iGMAS were collected to analyze the effects of different types of the receivers on various biases, and then a unified multi-system biases estimation model was proposed. The results show that there are some biases of ISBs in GNSS systems and the biases are affected by stations. The variation of GLONASS satellites has a unified tendency and the ISBs of BDS has a fluctuation property, which need to be improved.

Changhui Xu, Hu Wang, Yamin Dang, Hao Chen, Longping Zhang

Chapter 24. The Study on Ocean Ice Intensity Surveyed by GNSS-R Signal on the Coast

Intensity and thickness of sea ice are the basic parameters of ocean ice disaster monitoring. Compared with other detection methods, GNSS-R with high spatial and temporal resolution, lower cost, abundant sources, etc. has huge potential. Based on electromagnetic theory, the principle of GNSS-R inversion technology of sea ice intensity and thickness will be systematically studied on. Then the experiment of surveying ice thickness and intensity by GNSS-R was performed at Bohai Gulf in Tianjin of China from 17 to 18 in January 2014 in order to study the relation between the polarization ratio (between direct and reflected signal) and ice intensity. The result of the experiment has shown that the relation between polarization ratio and ice intensity is existent.

Fuyang Ke, Fangyuan Chen, Yunchang Cao

Chapter 25. Research on Tracking Technology of High Sensitive BD Signals

With the increasingly demanding for navigation and positioning about BD second generation satellite system, many users’ applications are in the city, jungle, interior and complex environments, such as the battlefield of human disturbance. Therefore the requirement for receiver becomes more and more high, in order to meet the demand of the application of complex environment, high sensitive receiver has become a hot topic in the current navigation of receiver in the field of technology. In this paper we propose the algorithm of weak signal, the main content include studying on fine acquisition, coherent integral for long time, EKF tracking and a synchronous and related techniques so on.

Zheng Zhao, Li Li

Chapter 26. Characteristic Analysis for Regional Traffic Data Using Random Matrix Theory

Traffic regional feature analysis of city is an important problem in the study of macro transportation system. The analysis of the current traffic regional feature of the city is mainly through the floating car data, such as velocity’s average or variance to characterize the features of different regions. But with the increasing scale of the traffic data in sampling and storage, the average (or variance) velocity as the evaluation of city traffic regional feature such as distinguishing urban and suburb has no significant through our analysis. Therefore, in this paper, we use the Random Matrix Theory (RMT) to analysis traffic data, which is based on floating car position data’s distribution of singular value equivalence matrix eigenvalue to distinguish different region such as urban and suburban. By using 1 week’s floating car data, we verify the data’s eigenvalue of singular value equivalent matrix distribution is better than the velocity’s average or variance in indicating the regional feature of city traffic.

Haichun Liu, Changchun Pan, Genke Yang, Chunxia Zhang, Robert C. Qiu

Chapter 27. Impact Analysis of Differential Code Biases of GPS Satellites on the Kinematic Precise Point Positioning

When the IGS precise orbits and clocks are used to carry on kinematic PPP, it is necessary to make DCB correction according to different types of GPS receivers. Currently, it is well known that DCB has little influence on static PPP, but there is still much work to do about the influence of DCB on kinematic PPP. This paper has a thorough evaluation on that and compares the kinematic results with the P1P2 type receiver by processing observation data from 20 IGS tracking stations. The results show that the accuracy of kinematic PPP of the NONCC receiver reporting C1 and P2 types has improved after DCB correction, but is still lower than that of the NONCC receiver reporting P1 and P2 types, especially in the zenith direction and the difference can reach more than 2 cm. The results indicate that there is a need to improve the accuracy of DCB published by IGS analysis center.

Shoujian Zhang, Lei Zhao

BDS/GNSS Test and Assessment Technology


Chapter 28. Performance Improvements of Combined Satellites Navigation System with System Time Offset

The time offset between different navigation systems are called the system time offset. It can be calculated either at user receiver, monitored by the public institutes or broadcast via the navigation message by navigation system. Currently, the research topic about system time offset is focused on how to accurately obtain its value. However, this paper will pay attention to the application of system time offset in combined navigation systems. The performance improvements of positioning accuracy and availability especially in the case of limited satellite visibility will be analyzed in this paper. According to the distribution of azimuth of visible satellites, ten different circumstances are simulated to implement the following researches. The first aspect is to analyze the improvements on PDOP and positioning accuracy with the application of system time offset. And the second aspect is to study the advancement in the ability of fault detection and exclusion with system time offset. The results indicate that the effects in improving availability and integrity become more obvious with the aggravating of obscured satellite visibility. Besides, the length of time that PDOP is smaller than 6 increases at most 3 h, equivalently 22 % improvements of availability. And the positioning accuracy in East direction enhances 41 %, North direction 61 % and Up direction 46 %. Meanwhile, the MDB of GPS satellites meanly decrease 17 m and coefficient decreases 0.24 in the worst condition with the system time offset.

Longxia Xu, Ye Ren, Xiaohui Li, Dandan Li

Chapter 29. Modeling and Multi-state Analysis for Availability of a Navigation Monitor Network

For characteristics of reliability, maintainability, supportability and multi-state about a navigation monitor network under real environment, Petri net (PN) and Bayesian network (BN) are applied integrated to availability modeling and analysis of a navigation monitor network in this paper. The relationship of equipments and MTBF, MTTR, MADT, sufficiency, MSRT of spaces are combined for availability modeling of monitor stations by PN. According to normal, degraded and failed states of monitor stations, availability modeling of the monitor network are obtained by BN. By analysis, nominal availability, degraded availability and failed state probability of the monitor network and weakness of monitor stations are confirmed. The multiple schemes are proposed and compared for improving availability. The result shows, improving sufficiency plays a more role in improving availability under real environment, and this method can be used for availability modeling and analysis.

Zhuopeng Yang, Feng Xue, Jinjing Wang, Heng Zheng

Chapter 30. A GNSS Multipath Detecting Method Based on Antenna Arrays

Although most GNSS monitoring stations located in open and clear places, multipath effects by surrounding environment could not be avoided, which leads to severely degraded observations of GNSS monitoring stations. This paper proposed a multipath detecting method based on antenna arrays, benefiting from different arriving angles of the multipath signal and the satellite signal. This method firstly computes the arriving angle of the satellite signal based on prior information such as satellite ephemeris, the coordinate of the monitoring station, etc. Then the steering vector of the satellite signal is obtained referring to the relative position of the array element. We design the array weights according to the steering vector, so as to minimize the satellite signal power of the array output. Therefore, if there is multipath in the received signal, the correlation peak could be detected in the array output, otherwise could not be detected. So we connect the array output to a GNSS receiver. When the receiver gives out observations such as pseudo-ranges and carrier phases, we predicate multipath to be existed in the received signal. When the receiver is not able to capture the satellite signal, there is no multipath which could affect the observations. Simulations based on software receiver show that the proposed method is able to detect multipath in the received signal quickly and effectively. The results could be used either in evaluating the signal quality of the monitoring stations, or in eliminating the multipath.

Min Li, Wei Zhao, Liang Yuan, Qinli Liu

Chapter 31. Reliability Allocation Method of Satellite Navigation System Based on Dynamic Simulation

A reliability allocation method of satellite navigation system based on dynamic simulation is proposed in this paper. First, Bayesian network is used for allocating the service availability and continuity to a slot. Then, the dynamic colored Petri net is applied to modeling the navigation information flow, which describes the availability and reliability associating the slot with the satellite, control center, mission up-link station and sensor station. Meanwhile, Monte Carlo simulation method is used to determine the availability and reliability index of key functional units. Finally, under conditions of the allocation availability and reliability index, the service availability and continuity is got with the bottom-up approach. Results are consistent with the original allocated values, which verify the validity of the proposed method.

Heng Zheng, Haisheng Li, Chang Li, En Xue, Zhuopeng Yang, Peipei Gong

Chapter 32. A Study on Measuring Channel Bias in GNSS Receiver

The Channel Bias of GNSS Receiver affects the precise measurement of navigation signals. It is important to correct the channel bias of GNSS Receiver for precise orbit and clock products in multi-GNSS data analysis. Based on the refined pseudorange observation error mode, the paper proposes a new method of measuring channel bias of GNSS Receiver by using GNSS simulator, which can measure the bias in the same frequency of the same system, between the different frequencies, between the different systems. Finally, this paper uses this method to test three types of iGMAS receivers, the results show that the channel bias in the same frequency is about 0.01 ns, while that in the different frequencies and the different systems is about 0.1 and 20 ns respectively, and all these bias are related with the receiver type.

Hailong Chen, Wen Li, Xin Liu, Wenhai Jiao

Chapter 33. The Development, Test and Application of New Technology on Beidou/GPS Dual-Mode Pseudolites

Satellite navigation signal was easy to be influenced by urban canyon, highway tunnel, indoor and underground garage. In view of this shading problem, the Beidou/GPS dual-mode pseudolites was developed in China. Firstly, the composition and technical characteristic of pseudolites was introduced. Secondly, Pseudolites compatible with Beidou/GPS signal, navigation message and anti near-far effect was described, then put forward a new high precision time synchronization algorithm between pseudolites and Beidou/GPS. Thirdly, the range stability, navigation chip compatible reception ability, signal coverage and the positioning accuracy was tested in the infield and outfield environment. Test results showed that: by the new time synchronization algorithm, the properties of rubidium clock or crystal oscillator to drive the pseudolites was basically the same, so this pseudolites could use a cheap crystal as the time frequency unit. Under the combined solution between pseudolites and Beidou/GPS, pseudolites could improve the geometric distribution and the positioning accuracy of the navigation system from 10 m up to 5 m. Finally, Verifying the enhanced capabilities of pseudolites in the Mountain valley environment through the practical application data of Jiuzhaigou National Park, the related research results will improve the high availability of China’s Beidou satellite navigation system.

Xingli Gan, Baoguo Yu, Lei Chao, Shi Liu

Chapter 34. Study on Judgment Method of Signal Correlation Performance Based on Complex Correlation Vector

For a long time, the satellite navigation signals are performed in a relatively simple BPSK or QPSK modulation of pseudo code and data for loading data information and time information. However, since the USA GPS modernization, the European Galileo satellite navigation system begins to demonstrate, new ideas and new methods for design and receiving signal appear continuously. With the use of AltBOC baseband signal form, we urgent need more complete presentation of a signal related performance. In this paper, the processing of traditional signal and the complex baseband signal was analysed. And the method of complex correlation vector diagram was studied for judgment signal correlation performance. The correlation vector analysis method is given in the process of receiving the actual signal. The method and result provides performance analysis guide for receiving the navigation signals by jointing I and Q branch and receiving full bandwidth AltBOC signal.

Ying Wang, Zhe Su, Yansong Meng, Xiaoxia Tao

Chapter 35. The Analysis of GNSS SIS Accuracy

With the rapid development of the global navigation satellite system (GNSS), to build the corresponding GNSS monitoring and evaluation system, has a great realistic significance to the operation condition of the BDS satellite navigation system and various performance indicators for monitoring and evaluation. At present, the International GNSS Monitoring And Assessment Service (iGMAS) launched by China in the world is building in an orderly way. This article direct at GNSS navigation space signal, use the four system’s precise ephemeris data and hybrid broadcast ephemeris data from January to October in 2014 to calculate and analysis; Direct at the characteristics of single and mixed constellation, derivation the calculation formula of the SISURE (Signal-in-Space User Range Error); Do statistical analysis and accuracy evaluation to the broadcast ephemeris data based on the four system precise ephemeris data. The calculation results and analysis shows that: the SISURE accuracy of the four systems by broadcast ephemeris is better than 2.5 m.

Shuai Liu, Xiaolin Jia, Zhuoxi Ma

Chapter 36. BeiDou Satellite Multipath Characteristics Research-From the “Micro” Parameters Point of View

Multipath is one of the most important factors that affect the positioning accuracy of GNSS receivers. Traditionally, the Code-Minus-Carrier Multipath Observable (CMO) is used to study the characteristics of GPS multipath errors, which takes on period fluctuations. However, BeiDou System comprises of three types of satellite—MEO, IGSO and GEO, the orbits of which differ a lot with each other. The standing multipath observed in GEO multipath causes the fluctuation phenomenon obscure, making the research with CMO technique hard to continue. Up till now, only a few literatures focused on studying the characteristics of multipath ‘micro’ parameters like delay, attenuation, carrier phase and number with real-world signal data. Those parameters indeed reflect the behavior of multipath more straightforward. Therefore, the Code Amplitude Delay Lock Loop (CADLL) technique is used at this paper to decompose the multipath at its signal parameter level. The experiment results reveal that even the GEO multipath can also vary slowly because of the satellite perturbation. The GEO multipath fading period can be a few hours. However, the IGSO and the MEO multipath do not show much distinct difference. The specular multipath fading period of both IGSO and MEO is normally a few minutes, while the diffused multipath parameters take on steady behavior but last very short time. It is found as well that the multipath signal of all kinds of satellites bears the nature of limited existing time. Thus, the concept of multipath life-time is proposed in this paper to describe the statistical distribution of multipath lasting time as well as the multipath power variation feature during its life-time. Those models are useful for simulator design to emulate more precise multipath scenario.

Xin Chen, Xiaoran Fang, Yuze Wang, Yanhong Kou, Le Cai, Peilin Liu, Wenxian Yu

Chapter 37. Analysis and Evaluation Method of Multiple-Access Interference in Navigation Satellite Communication System

The reliability of monitoring and control directive communication is a crucial factor of GNSS control segment. As several high-speed communication links of CDMA system in a limited bandwidth of navigation satellite, the MAI (Multiple-Access Interference) would serious prejudice the stability and effectiveness of system. Traditional evaluation method simply based on C/N0 has a large error on BER for the particularity of MAI in limited bandwidth, which could hardly apply in control segment evaluation. To satisfied the need of the system stability and design of communication signal, put forward an accurate modeling and analysis which obtain a result of worst and best signal status of MAI, and put forward a analysis and evaluation method based on signal parameters included of PRN, code phase, polarization phase, cross-correlation distribution estimated parameter and so on. A test system of GNSS limited band communication was established, the test results prove the effectiveness of the method, and achieve the BER in the auxiliary of multi-user detection method of multi-channel high-speed communication system. The research achievements provide the basis for TT&C (telemetry tracking and command) of BeiDou control segment.

Chenglong He, Baoguo Yu

Chapter 38. Research Progress on TWSTFT Mobile Calibration Station

To achieve more precision calibration between two any signal system’ ground stations of two-way satellite time and frequency transfer (TWSTFT), a new TWSTFT calibration method is proposed based on two TWSTFT mobile stations to calibrate systematic error of time comparison between any two ground stations. Two TWSTFT mobile stations are developed. To measure the systemic error between the two mobile stations, a zero baseline comparison experiment is designed. The standard deviation of equipment delay of two mobile stations are respective 0.102, 0.038 ns. The standard deviation of systematic error of zero baseline comparison is 0.124 ns. To validate function of two mobile stations, a long baseline comparison experiment is designed between two ground stations at Tianjin and Lintong. The result is highly consistent with GPS Common-View comparison between two stations. To farther validate performance of two mobile stations, a long baseline comparison experiment be designed between two ground stations at Changchun and Lintong. The result is shown that the standard deviation of clock difference of two ground stations is 0.347 ns after moving the drift of cesium atomic clock at Changchun. The two TWSTFT mobile stations can implement calibration of systematic error of time comparison between any two ground stations.

Guoyong Wang, Ya Liu, Xiaohui Li, Chen Shi

Chapter 39. Analysis of BeiDou Signals on the Accuracy of Common-View Time Transfer

The BeiDou navigation satellite system is being in the initial period of providing service. Currently, this system is broadcasting three signals, narrow correlation, wide correlation and anti-multipath, on both I and Q branches of B1, B2 and B3 frequency. One can get the pseudo-range measurements publicly on the civil frequency with a corresponding receiver. This paper firstly analyzed the influence of different satellites types, GEO, MEO and IGSO in BeiDou constellation, on the precision of common view time transfer. The conclusion indicates that the one can achieve the best precision of common view time transfer with GEO satellites among the three different satellites types. Based on this conclusion, this paper further analyzes the impact of different observation types, C/A measurements on any frequency and assembled dual frequency observations of any two frequencies, on the precision of common view time transfer. The results of common view time transfer are evaluated with stability, accuracy and standard deviation of residuals. Except the combination of B2 and B3 and the wide correlation combinations of dual frequency, the results obtained from the other combinations of dual frequency observations perform better than that from any single frequency. The result of B1IA is better than other single frequency, the residual standard deviation is 2.32, the stability of million seconds is 3.18e-13 and the accuracy is 4.16e-13. Among the results of all the dual frequency observations, the combination of B1IA and B2IA provides the best precision with the standard deviation of residuals being 1.36, the stability of million seconds being 2.11e-13 and the accuracy being 5.71e-13.

MeiJun Guo, Hua Lu, Yun Xiao, YiJun Mo, XiaoGang Liu

Chapter 40. Assessment of BDS Signal-in-Space Accuracy and Standard Positioning Performance During 2013 and 2014

At the end of 2011, BeiDou Satellite Navigation System (BDS) moved into the phase of experimental operation, indicating that BDS, after GPS and GLONASS, became the third satellite system providing free service of PNT. In this paper, the positioning performance of BDS from Jan, 2013 was assessed. The data sources, as well as the generation of precise orbit and clock, were described, and the precisions of broadcast orbit, clock and signal in space for GEO/IGSO/MEO satellites were analyzed. The civil signal B1I of BDS was utilized to assess the accuracy of single point positioning (SPP) with code measurements. It is illustrated that the precision of URE for BDS could reach 1.5–2.0 m, and that the both horizontal and vertical precision of SPP reach 10 m in service area.

Gucang Chen, Zhigang Hu, Guangxing Wang, Guo Chen, Zhaoying Liu, Qile Zhao

Chapter 41. Design and Implementation of Distributed Simulation Testbed for GNSS Experimentation

Global navigation satellite system (GNSS) is a complex astronautic project of great size. There are several steps in the construction process including system design, equipment development and system test procedure. The system design output such as system interface, operation flow and key performance will be validated with simulation experiment in the system design procedure. The real system interface implementation and key performance will be tested in the equipment development and system test procedure. A distributed simulation testbed is provided for the simulation experiment and system test. The simulation testbed structure, key technology, system implementation and applications are described in the paper.

Long Yang, Yufei Yang, Jinping Chen

Chapter 42. High Precision and Difference Measurement of Inter-element Amplitude and Phase Bias Errors Based on Channel Multiplexing

Modern satellite navigation system receiver use adaptive antenna array to suppress the RF interference and mitigate multipath signals in different directions from signals of interest. The inter-element amplitude and phase bias errors can cause performance degradation in the receiver. This paper presents a measurement with high precision in anechoic chamber, where channel multiplexing, difference measuring is used to decrease bias error caused by too many measuring data. And calibrating equation is put forward based on the three-dimensional rotating turntable, so that inter-element wave-way difference can be removed. Analyses show that the measuring precision can be increased by nearly double with low complexity and high efficiency. Then an automatic measuring system is designed, and data is measured by a multichannel vector network analyzer. A four elements array are measured, comparison between the measuring and simulating results demonstrates that the phase error is less than 8° while the efficiency is improved by nearly 4 times to conventional measurement.

Ke Zhang, Huaming Chen, Xiangwei Zhu, Guangfu Sun

Chapter 43. A High-Precision and Flexible Array Antenna Signal Simulator Based on VFD Filter

An array antenna signal simulator based on VFD filter is presented. To offer the design structure and make delay control more flexible, the VFD filter, which is suitable for changing the delay time, is used to control the delay of different channels. To improve the group delay precision of VFD filter, a design method in group delay minimax sense is proposed, instead of the variable frequency response criterion. The experimental results indicate that, in the DOA simulation, the elevation simulation accuracy of the new designed array simulator is better than 2°, the azimuth simulation accuracy is better than 1°.

Hai Sha, Han Mu, Hui Zhang

Chapter 44. New Generation Signal Structure Evaluation System for GNSS

The evaluation of signal structure is an important phase of the signal structure design in the process of GPS modernization, Galileo and BDS construction. The new generation navigation signals of global navigation satellite system (GNSS) have the characteristics of diversification of signal structure, large bandwidth and complicated receiving method. Based on this, a new generation signal structure evaluation system (NGSSES) was proposed. The NGSSES is flexible to configure, and the bandwidth and sampling rate can up to 250 and 150 MHz, respectively. The output signals have the power of resolution of 0.5 dB. The performance of code and carrier tracking accuracy of BOC(14,2) under single channel and channel combining tracking methods, multipath of TMBOC(6,1,4/33) under matching and non-matching methods are evaluated using NGSSES. The anti-jamming performance of BOC(14,2) and AltBOC(15,10), compatibility of BDS B1 BOC(14,2) and GPS L1M BOC(10,5) are also evaluated using NGSSES. The experimental results verified the feasibility and effectiveness of NGSSES.

Jianlei Yang, Tian Jin, Zhigang Huang, Honglei Qin

Chapter 45. Research of Satellite Receiver Anti-replay Attack Techniques

With the broad application of satellite navigation technique in the society and economy development, the satellite navigation technique has been facing with more and more hidden dangers of being attacked in such key fields as finance, public security, civil aviation and public rescue. In light of the vulnerability of satellite navigation receiver against replay attack in the above fields, this paper proposes several anti-replay attack techniques of low complexity, i.e., inertial positioning test, clock skew test and Doppler shift test. The simulation results show that Doppler shift test can resist replay attack effectively without additional hardware to the receiver. In addition, compared to SNR test, absolute power test and the other techniques, Doppler shift test has the advantages of low implementation difficulty and high adaptability, which can provide technical support for the security applications of satellite navigation technology in the fields of great concern.

Mengjiang Liu, Zhixin Deng, Li Jun

Chapter 46. Detect Techniques and Test Analysis on Navigation Signal Code Correlation Peak

The signal quality impacts the precision of the user’s Positioning, Navigation and Timing (PNT) provided by the satellite navigation system. The satellite navigation system must monitor the navigation signal quality and gives alarm. During operating of the system, the signal code correlation peak detection is an important work in monitoring, evaluation and control for the navigation signal quality. According to the structure of navigation satellite payload, ICAO (International Civil Aviation Organization) provides the 2OS (2nd-Order Step Threat Model) abnormal signal model, and gives code correlation peak for every abnormal signal. The paper analyses several correlation peak detect techniques based multi-correlator, and gives detection results of the BeiDou system’s navigation signal using the especial navigation signal monitoring system of the BeiDou satellite navigation system.

Xiaochao Feng, Yongheng Fu, Lei Gong, Jiancheng Liu

Chapter 47. Research on Time Synchronization Method of Ground-Based Navigation System

In the complex environment, such as in mountainous area, under-ground, urban, in-door situations, the satellite navigation signal will be kept out, which makes the user’s receiver unable to receive enough navigation signal to position itself. Ground-Based Navigation System can flexibly deploy ground-based navigation based station according to different environment. It provides navigation signal with high quality to meet the user’s needs, so it increases the coverage of the navigation service. With the same principle as satellite navigation system, the user uses the ground-based navigation stations as time and space base to determine its position and time. Comparing with the satellite, the coordinate of ground-based navigation station can be obtained with higher accuracy, which makes the inter-station time synchronization become the very important factor to impact the precision of positioning. To achieve cost-effective and accurate inter-station time synchronization, a time and frequency lock method based on two-way time transfer is proposed in this paper, measurement error model is established, and the synchronization flow is established under the typical ground-based navigation signal framework, i.e. the ‘CDMA+TDMA’ framework. It not only realizes two-way time difference measurement and navigation signal transmission in the same time, but also tracks time-frequency change through time and frequency lock technology, as a result, the effect of troposphere delay can be reduced and the accuracy of time synchronization can be significantly improved. The simulation and experiment results show that the time synchronization accuracy is better than 1 ns.

Xiye Guo, Yongbin Zhou, Jun Yang

Chapter 48. BDS/GPS Stochastic Model Refinement and Assessment Using Satellite Elevation Angle and SNR

Satellite elevation angle and Signal-to-Noise Ratio (SNR) are usually used as measurement quality indicators for global navigation satellite system (GNSS) measurements. The relationship of quality indicators and accuracies of measurements can be expressed as stochastic models. To model the relationship for Beidou navigation satellite system (BDS) and global position system (GPS), five basic stochastic models are presented from satellite elevation angle and SNR. Also, coefficients of these models are refined. It’s found that SNR stochastic models with same coefficients can’t treat all measurements from BDS and GPS. Moreover, stochastic models with an additive constant could model the relationship better. The performance of the five models are tested, independent and combined, in BDS/GPS precise positioning. The results show that refined stochastic models could improve the success rate of integer ambiguity single-epoch solution 8 % comparing to empirical models. Models with an additive constant could improve the success rate 10 % comparing to models without additive constants. SNR model with an additive constant performs better in performance for integer ambiguity resolution, especially for low elevation satellite or combined system. Using stochastic models with an additive constant, ratios of posteriori and prior variances are closer to 1 in precise positioning. Therefore, for the used receivers, we suggest to choose refined stochastic models with an additive constant, and give priority to SNR model. Here, a refinement and assessment method is proposed to derive proper stochastic models for GNSS data processing, taking into account the differences between navigation satellite systems (e.g. BDS and GPS) and stochastic models.

Yan Li, Huang Dingfa, Li Meng, Zhu Dongwei

BDS/GNSS User Terminal Technology


Chapter 49. A GLONASS Navigation Data Verification Algorithm Under High Bit-error Rates

This paper analyzes some GLONASS abnormal data of receiver software processing, and locates the source of the problem in navigation data handling error under high bit-error rates. Through the derivation of the Hamming check method, limitations of the method and mistakes in the interface document were pointed out. This paper proposes a navigation data verification algorithm under high bit-error rates.

Jian Hu, Aishui Rao, Long Zhang, Yimei Sun

Chapter 50. The Design and Implementation of an Acquisition Scheme for Weak GNSS Signal

In order to improve the adaptability of GNSS receivers in weak signal circumstances, this paper designed an acquisition scheme, which could be applied to all GNSS signals, and implemented it on the FPGA platform. Code-phases and carrier frequencies were searched partial-parallel in the scheme, and the searching origin could be configured flexibly. In the phase of pre-detection integration, the signal-noise ratio of detection was enhanced by extending the non-coherent integration time. Since the autocorrelation function of pseudo-code would distort due to the code Doppler while the integration time was extended, two compensation methods were adopted during the procedures of down-sampling and non-coherent integration, respectively. In the phase of detection, a two-stage detector with immediate-rejection was employed, in which a modified location constraint scheme was proposed to suit the lengthened integration time. After an analysis of the detection performance of the acquisition scheme, its implementation principles on FPGA were introduced. In the last part, a hardware test platform was built based on a signal simulator and the acquisition sensitivity of the scheme was tested. The test result showed that the acquisition sensitivity was about −145 dBm when the detection probability was not less than 90 % and the false-alarm probability was not more than 1e-6.

Linfeng Zhang, Hairong Guo, Chong Zheng, Haibo He

Chapter 51. Adaptive Notch Filter Design Based on Krylov Subspace

Time-domain adaptive filtering as a narrow-band interference suppression technique has great potential and broad prospects in navigation receiver anti-interference applications. In this paper, an adaptive notch filter design method based on Krylov subspace is put forward which achieves adaptive narrow-band interference suppression and optimal output SNR for navigation receivers. The method solves the issue of large computation amount in traditional Wiener filtering algorithm due to matrix inversion. Simulation results show that the algorithm has a simple structure and lower computation than that of the optimal filter. Thus, it is a practical algorithm for narrow-band interference suppression.

Zhaoliang Duan, Guangwei Fan, Yi Luo

Chapter 52. A Novel High Dynamic Carrier Tracking Algorithm Based on the Gaussian Particle Filter

The particle filter based tracking algorithms were researched for the GNSS receiver. Traditional GNSS receivers encounter a difficult problem with high Doppler shift and its derivatives in high dynamic scenarios. To track this shift correctly, the bandwidth of tracking loops must increase, which inevitably induces more broadband noise and may lead to a loss-of-lock at low SNR conditions. In this paper, a novel high dynamic carrier tracking algorithm based on the Gaussian particle filter (GPF) is proposed. The GPF approximates the posterior density by estimating parameters of Gaussian densities based on particle approach at each loop update, which avoids the problem of particle degeneracy. To deal with the problem of divergence and to obtain a better robustness, two optimization methods are also proposed: the STF-GPF and the UGPF. Extensive evaluations on the proposed model and algorithms are conducted with different levels of signal-to-noise ratios (SNRs). The numerical simulation results show that the proposed GPF tracking loop and consistently outperform the conventional approaches, as well as achieving lower SNR sensitivity in comparison with EKF and UKF. Both optimization methods improve tracking accuracy than GPF.

Qize Chen, Gengmin Li, Ao Peng

Chapter 53. Research on the Mast Antenna System for Communications Compounds Satellite Navigation

In this paper, a mast antenna for communications consists of satellite navigation and UHF/VHF antenna is proposed. On the top of the mast system includes a satellite navigation antenna which is fed by the L-probe with its phase difference of 90°. Under the antenna a broadband omni-directional antenna utilize dual-parasitic structures with a metal pole through the radiator for UHF/VHF operation is designed. The radiator includes biconical-structure and thick dipole in order to reducing the size, by use of this structure to improve the impedance. The working frequency of the satellite navigation antenna can cover BD, GPS, Glonass satellite navigation system. The working frequency band of the VHF/UHF antenna is 120–550 MHz. In the whole band the VSWR is less than 2.5. The measured and simulated results show that the antenna has good radiation pattern properties over high and low frequency. All the efficient results show that the UHF/VHF antenna can combine satellite navigation antenna well to form a new mast antenna system that has important utility values in multi-functional satellite navigation communication.

Haiguang Zhang, Ximing Liang, Jia Zhang

Chapter 54. Research on the Satellite Navigation Independent Compound Receiving and Transmitting Array Concept

In this paper, the theory of satellite navigation independent compound receiving and transmitting array is proposed. Analyze the feasibility of satellite navigation receiving array, microwave energy transmitting array, RF rectification array and energy independent network. Explore the possibility framework of MEMS multifunction skin array. The concept of possibility application mode of array system in outer space, heaven and ground is proposed based on the simulation, analysis and experiment results. The elementary ideas in this paper have some reference value in development of BD system.

Ximing Liang, Haiguang Zhang, Jia Zhang

Chapter 55. A Framework of Mathematic Model and Performance Evaluation for Conjunct GNSS Spoofing Detection

GNSS spoofing is extremely deceitful and destructive for receivers. To guarantee safe access to GNSS, reliable spoofing detection is very important, especially for some critical GNSS applications and services. A great many spoofing detection techniques have been proposed in the last decade, they may be demonstrated to be effective for a special spoofing attack scenario. Nevertheless, there are few studies on generic and formal analysis on GNSS spoofing detection. In addition, there is no consolidated performance evaluation system for spoofing detection, which results in ambiguous interpretations. Therefore, a generalized mathematical model for conjunct GNSS spoofing detection based on Dempster-Shafer theory is proposed in this paper, and a performance evaluation framework for the proposed mathematical model is provided as well. To the authors’ knowledge, the research is not only helpful for the researchers to propose new methods for spoofing detection and corresponding performance analysis, but also helpful for spoofing detection system construction. At last, simulation results are provided to demonstrate the theoretical derivations.

Dingbo Yuan, Hong Li, Mingquan Lu

Chapter 56. A Near-Far Effect Mitigation Method of Pseudolites Based on Array Signal

This paper proposes a new near-far effect mitigation method based on array signal to resolve the near-far problem in pseudolites. It can adjust the power intensity of the pseudolite by constraining the beam direction to make it accord with the real navigational signal. Meanwhile, this method achieves maximum interference signal filtering, thus the navigation receiver can work properly under the concurrence of pseudolites, strong interferences and navigation signals. The effectiveness of the proposed method is proved through simulations and performance analysis.

Libin Shen, Lixin Li, Huisheng Zhang, Tao Bao

Chapter 57. A Fast Positioning Method for Hot Start in GNSS Receiver

Time to First Fix (TTFF) is an important parameter used for the evaluation of the performance of a GNSS receiver. For most mass market applications, it is attractive that the GNSS receiver has a first position fix within few seconds, while providing a relatively accurate first fix output. A short TTFF can be obtained by using Akopian’s iterative estimation of satellite time of transmissions with a least-square method. The position computation needs at least five satellites in Akopian’s method. However, several factors (such as 1-ms fuzziness and mis-acquisition, etc.) limit the usage of Akopian’s method. This paper proposes the corresponding schemes to solve these problems and give a reliable and feasible fast positioning method considering both TTFF and the accuracy.

Xiaohui Ba, Shidong Luo, Haiyang Liu, Qing Yuan, Yun Wang, Jie Chen

Chapter 58. A New Iterative Method for Multipath Mitigation

Multipath is the dominant source of positioning error in modern GNSS receiver. Maximum likelihood (ML) parameter estimation is an optimal method to mitigate the multipath effects while ML involves nonlinear optimization and requires iterative algorithms. Iterative methods usually lack of global convergence when the paths are closely spaced, if the initial value is arbitrarily assigned. In this paper, however, we first employ a grid search method to choose the initial value before iteration. Most computation of the grid search can be done offline. After that, an iterative method with simple forms is used to improve the parameter accuracy and global convergence can be achieved with just a few iterations. The simulations results show the estimator of time delay is almost unbiased when the time relative delay of two paths is larger than 0.20 chips.

Yan Gao, Wei Li, Jinli Li, Hongliang Qu, Xiang Shi

Chapter 59. An Improved Practical Anti-jamming Technique for GNSS Receivers Based ADP in Frequency Domain

Anti-jamming techniques have been widely researched to enhance the reliability and effectivity of Global Navigation Satellite System (GNSS). Amplitude Domain Processing (ADP) is an anti-jamming method base on Locally Most Powerful (LMP) detection theory. While it works efficiently when dealing with some relatively simple interferences, such as one or two continuous wave interferences, it has a limitation when submitted to multiple interference scenarios. Then, some later researches prove that using ADP in frequency domain (FADP) would give a more superior performance, and put forward a simple global framework of this method. However, there are still several important specific problems needing to be solved before FADP’s being brought into practice, as the spectrum leakage and malignant distribution of the frequency domain statistical data would surely degrade the performance of the method or even invalidate it. In this paper, an improved anti-jamming technique based on FADP is proposed, which is more robust for practical consideration. Firstly, a windowed FFT is used to inhibit the spectrum leakage and signal distortion, as well as the pattern of overlap-adding is chosen to minimize the degradation of the SNR. Then, along with the analysis of the differences between statistical characteristics of the time-domain waveform and spectrum data, a specialized mathematical function of ADP is designed, responding to the wide range and malignant distribution of spectrum data. Meanwhile, a simplification of the procedures also eliminates the need of mutual transformation between Cartesian coordinates and polar coordinates, saving the computation and storage resources in some way. Simulation results demonstrate that the proposed improved FADP method performs more efficaciously in realistic situation than the original one.

Tianqiao Zhang, Yao Wang, Yang Gao, Hongbing Wang

Chapter 60. A Robust Dynamic Satellite-Searching Algorithm for Multi-constellation GNSS Receivers

With the flourish development of GNSS community, the number of available navigation satellites is increasing rapidly. Benefiting from the super constellation consisting of satellites from various systems, the availability and reliability of positioning service are improved for multi-constellation GNSS receivers. Meanwhile, the complexity and uncertainty in satellite-searching process are multiplied as well, which significantly increases the receiver’s time to first fix (TTFF) and decreases its performance. Dynamic satellite-searching algorithms can be employed to reduce TTFF. However, existing dynamic satellite-searching algorithm is not robust and efficient enough when masking problem exists. In this paper, a robust dynamic satellite-searching algorithm is proposed. Theoretical analysis and numeric simulations in masking situation are presented, and proves the efficiency and robustness of the new algorithm. In conclusion, the new dynamic satellite-searching algorithm provides an efficient and robust solution to practical multi-constellation GNSS receivers.

Hengwei Zhou, Zheng Yao, Mingquan Lu

Chapter 61. A High-Dynamic Null-Widen GNSS Anti-jamming Algorithm Based on Reduced-Dimension Space-Time Adaptive Processing

Space-Time Adaptive Processing (STAP) is an effective method to suppress interference in Global Navigation Satellite System (GNSS). But in high-dynamic environment, conventional adaptive anti-jamming algorithms are invalid since jammers may easily move out of the array pattern nulls. To solve this problem, a new null-widen method based on the Laplace distribution model is deduced in this paper, the method can get wider null at direction of jammers. However this method is computationally intensive by using STAP, thus a new null-widen method based on reduced-dimension multistage wiener filters (MWF) is deduced here. It has proved in simulation section that the new method can get better performance in few snapshots.

Lu Ge, Dan Lu, Wenyi Wang, Lu Wang, Qiongqiong Jia, Renbiao Wu

Chapter 62. Interference Suppression with L1-Norm Constraint for Satellite Navigation Systems

Currently, there have been many studies of interference suppression for satellite navigation systems. Power minimization approach is an effective interference suppression algorithm. It forms automatically deep nulls in the DOAs (direction of arrival) of interferences without prior information about the DOAs of satellite signals and interferences. However, the power minimization approach can not provide flat gains in other directions. Thus there will be fluctuation in the beampattern, especially when the number of snapshots is not enough. It means that the desired satellite signal may be partly suppressed when they locate in the shallow nulls. In this paper, by combining eigenvalue thresholding method and l1-norm constraint, we propose a new interference suppression algorithm to suppress interferences and provide flat gains in all directions except that of interferences. The difference between the new algorithm and the conventional power minimization approach lies in the improvement of covariance matrix which is constituted based on the main eigenvalues and corresponding eigenvectors of covariance matrix. In addition, an explicit l1-norm constraint on the beam gains is exploited to provide flat gain in all directions except that of interferences. When there are interferences and spoofing, the spoofing is generally suppressed heavier than the authorized signal. It will decrease the power difference between the spoofing and authorized signals. Thus it will degrade the performance of subsequent spoofing detection. So the proposed algorithm also can be applied to the spoofing detection in satellite navigation systems. The simulations demonstrate the effectiveness of the proposed algorithm.

Wenyi Wang, Qingrong Du, Renbiao Wu, Dan Lu, Lu Wang, Qiongqiong Jia

Chapter 63. A Spoofing Mitigation Algorithm Based on Subspace Projection for GNSS Receiver

Spoofing attack can intentionally mislead the receiver to obtain the fake position or time by utilizing the counterfeit satellite signals. Although several anti-spoofing techniques have been reported to detect and suppress spoofing attack, most of the published researches are based on antenna array. In this paper, we present a spoofing mitigation algorithm based on subspace projection which is independent with antenna and even can be utilized in single-antenna GNSS receiver. With the acquired code phases, data-bit modulation, carrier frequencies and phase of all spoofing signals, the spoofing signals’ subspace matrix can be constructed. The projection of input signals onto the spoofing signals’ subspace is the sum of the spoofing signals and the projection of the noise. Then we can use the projection as an estimate of the spoofing signals. After subtracting the estimate from the input signals, the result consists of desired authorized signals, noises and the residue error resulted from the projection operation. We also prove that the performance of this method is independent of the carrier phases and data-bit modulation of the spoofing signals under special processing constraints. Besides, the BeiDou B1I signal has been tested to verify the validity of the subspace projection method.

Lei Chen, Shuai Han, Weixiao Meng, Zijun Gong

Chapter 64. A Quick A-BDS Location Method Based on Characteristics of GEO Satellite and Ridge Estimate

The calculation of traditional A-GPS time-free positioning method will be very complex without the approximate position. But hybrid constellation was adopted by BeiDou Navigation Satellite System (BDS). And the GEO satellite of BDS has high speed of NAV data rate. So a fast positioning method for BDS receiver based on characteristics of GEO satellite and ridge estimate was proposed in this paper. First, an approximate position was got by using ridge estimate with GEO constellation. The ridge estimation can solve problem of coefficient matrix ill-conditioned. Then the signal transmission time of MEO/IGSO satellite was restored with the approximate position. A simulation environment was built by using BDS broadcast ephemeris information. The white noise with 6 m standard deviation was added to pseudoranges. The success rate of the quick location method is big than 99.65 % in China surrounding area. And about 80 % of China surrounding area can 100 % guarantee to restore a complete satellite signal emission time and obtain an accurate position.

Shourang Jing, Wenxiang Liu, Ling Yong, Guangfu Sun

Chapter 65. Feasibility Analysis of GNSS Multi-constellation Positioning for Lunar Spacecraft

With the development of deep space exploration technology, as the representative project of the Chinese lunar exploration, the possibility of using global navigation satellite system (GNSS) for deep space exploration spacecraft positioning has become a hot issue. Based on the existing GNSS research on high orbital spacecraft positioning, the feasibility of using GNSS multi-constellation for lunar orbit spacecraft positioning is deep analyzed. On condition of signal acquisition’s lowest carrier to noise ratio (CNR) threshold, 21 dB Hz, two cases of signal receiving are analyzed from which GNSS satellite transmitting antenna beam’s main lobe and side lobe. Simulation results show that when only receiving the beam main lobe signal of GNSS transmitting antenna, any single constellation or multi-constellation combination of GNSS cannot satisfy positioning of lunar spacecraft on the lunar revolution orbit for whole period (about 27 days). When signals from the main lobe and side lobe of the GNSS received, three constellations combination or more can satisfy positioning for the whole lunar orbit period. Conclusion is that GNSS multi-constellation combination method is possible to complete the mission of deep space exploration project for lunar spacecraft positioning on the simulated conditions.

Lei Chen, Yangbo Huang, Wenxiang Liu, Gang Ou

Chapter 66. Spoofing Interference Suppression for GNSS Based on Estimating Steering Vectors

The paper proposes a spoofing interference suppression algorithm for multiple spoofing interferences existing simultaneously. First, the signals which received from the reference antenna array are captured. The information about visible satellite signals’ Doppler frequency and code delay are acquired. Using these information, we can reconstruct the visible satellite signals. Then, the visible satellite signals’ steering vectors are estimated by calculating cross-correlation between the estimated visible satellite signals and the antenna array received signals. Utilizing the normalized cross-correlation coefficients of the visible satellite signals’ steering vectors to detect spoofing interference and its steering vectors. Final, the proposed algorithm constructs an orthogonal projection matrix based on spoofing interference’ steering vectors. Spoofing interference are suppressed by utilizing the constructed orthogonal projection matrix. The proposed novel spoofing interference suppression algorithm can simultaneously suppress multiple spoofing interference, which does not need to know the array manifold in advance and the DOAs (Direction of Arrival) of satellite signals and spoofing interference.

Yaotian Zhang, Lu Wang, Wenyi Wang, Dan Lu, Qiongqiong Jia, Renbiao Wu

Chapter 67. Satellite Navigation Anti-jamming Algorithm Based on Extended Array

In the complex electromagnetic environment, the Global Navigation Satellite System (GNSS) was seriously influenced by the interference. The anti-jamming algorithm based on the uniform array have been widely used in GNSS interference suppression technology, but the number of the interference is limited by the number of the antenna sensor. This paper proposed an interference suppression algorithm based on the extended array, the algorithm could suppress more interference than the number of antenna sensor. Firstly, the covariance matrix of the non-uniform array is vectorized. After that, the spatial smoothing is used to build up the rank of the covariance matrix. With the smoothed covariance matrix, power inversion algorithm is used to estimate the directions of the interference. Then, forming an overdetermined equation based on the interference subspace and an arbitrary signal’s steering vector, whose direction is different form the interference. Finally, solving its least-squares solution to get the optimal weight, which can form nulls in the direction of interference without affecting the useful signal. The simulation results verify the effectiveness of the proposed algorithm.

Fusheng Li, Wenyi Wang, Dan Lu, Lu Wang, Qiongqiong Jia, Renbiao Wu

Chapter 68. Performance Assessment of Signal Quality Monitoring Based GNSS Spoofing Detection Techniques

People are putting a great concern on Global Navigation Satellite System (GNSS) security while enjoying its convenience. GNSS is vulnerable and easily interfered by jamming or spoofing because of its opening signal structure, low signal power and complicated transmission environment, and this may lead potential security accidents or losses. Intermediate spoofing is an efficient spoofing attack method which is able to implement spoofing attacks without interrupting the regular functioning of user receivers and being noticed. This paper applies signal quality monitoring (SQM) techniques to GNSS intermediate spoofing detection and assesses the performance. The basic principle of intermediate spoofing attacking process and its detection are explained at first, which shows its effects on tracking loop status. Then, the techniques of SQM based on single correlator and multicorrelator are discussed respectively and the factors affecting the performance are analyzed and evaluated in detail, such as the number of correlators, SNR and so on. At last the paper summarizes the performances of SQM for GNSS spoofing detection.

Yichen Yang, Hong Li, Mingquan Lu

Chapter 69. Robust SFAP Anti-jamming Algorithm Based on Generalized Sidelobe Cancellation

With the rapid development and the wide application of Global Navigation Satellite System (GNSS), anti-jamming technology has been widely studied and applied for anti-jamming satellite navigation receivers in recent years. The robust space-frequency adaptive processing (SFAP), combining array signal processing theory, adaptive filtering algorithm and Fast Fourier Transform (FFT), based on segmentation of the frequency-domain is proposed in this paper. And the method for calculating the anti-jamming weight of the frequency-domain based on Generalized Sidelobe Cancellers (GSC) is also presented, which reduces the dimension of the matrix during the process of the covariance matrix inversion. Consequently, it makes the system much easier to implement. In addition, the algorithm is improved further, combined with robust beamforming technology. Through notch widen against frequency-domain, the error that exist in the actual system, influencing the performance of algorithm, will be effectively reduced, and the adaptability for high dramatic environment will also be enhanced.

Long Liu, Zhaolin Zhang, Ling Wang

Chapter 70. Research on the BDS Inter-Satellite-Type Carrier Phase Bias Introduced by Different NH Code Sign Conventions

As for D1 NAV message broadcast by BDS MEO/IGSO satellites, a secondary code of Neumann-Hoffman (NH) code with length of 20 bits is modulated on ranging code. However, the secondary coding are not implemented on D2 NAV message from BDS GEO satellites. While different GNSS receivers from different manufactures were used for carrier phase difference applications, a bias of 180° (half a cycle) may be induced between those carrier phases obtained from two different sign conventions A and B. The bias would result in that RTK activities failed. For the issue mentioned in former content, this paper presents an intensive research on the rationale of the BDS inter-satellite-type carrier phase bias introduced by different NH code sign conventions. We select three kinds of most popular GNSS OEM boards for testing and verification. A serial of crossover trails and long-term stability tests are executed to identify the half-cycle carrier phase bias between the BDS signals which two different OEM boards output. In addition, we change the sign convention of NH code in the OEM board K508 of ComNav Technology for further validation. Based on our test results, the paper proposes a recommended solution as all GNSS device manufactures should take Convention B for dealing with NH code between different BDS signals, to avoid the inter-satellite-type carrier phase bias in RTK application.

Zuohu Li, Hailing Wu, Liduan Wang, Hui Liu

Chapter 71. A Position Calibration Algorithm of Antenna Arrays

The paper presents an adaptive position calibration algorithm of antenna arrays basing on the FW algorithm, in which the alternative iteration method is used. Simulation and theory analysis in Matlab shows that the proposed algorithm work well with good resolution.

Jiachi Wang, Zhongjun Chen

Chapter 72. Performance Analysis of a Dual-Frequency Software-Defined BeiDou Receiver with B1 and B2 Signals

The Chinese BeiDou Navigation Satellite System (BDS) is one of the fastest emerging Global Navigation Satellite Systems (GNSS) that offers two civilian navigation signals through its 14 operational satellites as of November 2014. The release of the 2nd version of the BeiDou Interface Control Document (ICD) in December 2013 makes it possible for the researchers worldwide to investigate the performance of the 2nd civilian BeiDou B2 signal along with the legacy BeiDou B1 signal. In this paper, the researchers at the Finnish Geospatial Research Institute (FGI) make an effort to analyze the performance of BeiDou B1 and B2 signals in Finland considering the similarities and differences between the signals that affect the final positioning result. The performance analysis is carried out in a software-defined multi-frequency multi-GNSS research receiver developed at FGI. The data collection and the result analysis are carried out in two steps. In the first step, a hardware multi-frequency multi-GNSS simulator is utilized to verify the performance of the developed software-defined receiver. Afterwards, in the second step, the performance evaluation of BeiDou B1 and B2 signals is carried out with live data sets.

M. Zahidul H. Bhuiyan, Stefan Söderholm, Sarang Thombre, Laura Ruotsalainen, Heidi Kuusniemi
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