Research on Near-far Effect and anti-impact noise interference pseudo-code sequence blind estimation algorithm in Pseudo Satellite System

2020 ◽  
Author(s):  
Youming Li ◽  
Jinpeng Gao ◽  
Yuanfa Ji ◽  
Wentao Fu ◽  
Songke Zhao ◽  
...  
Keyword(s):  
Estimation Algorithm ◽  
Satellite System ◽  
Code Sequence ◽  
Blind Estimation ◽  
Noise Interference ◽  
Impact Noise

scholarly journals BDS B1I multipath channel statistical model comparison between static and dynamic scenarios in dense urban canyon environment

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Xin Chen ◽  
Di He ◽  
Ling Pei
Keyword(s):  
Model Comparison ◽  
Satellite Orbit ◽  
Estimation Algorithm ◽  
Intermediate Frequency ◽  
Satellite System ◽  
Multipath Channel ◽  
Navigation Satellite ◽  
Navigation Systems ◽  
Distribution Models ◽  
Channel Models

Abstract Global Navigation Satellite System (GNSS) multipath channel models are fundamental and critical for signal simulation and receiver performance evaluation. They also aid the designing of suitable multipath error mitigation algorithms when the properties of multipath channel are available. However, there is insufficient existing research on BeiDou Navigation Satellite System (BDS) signal multipath channel models. In this study, multipath channel statistical models are established on the basis of extensive datasets of the BDS B1I signal. A multipath parameter estimation algorithm is designed to extract information of multipath rays from the intermediate frequency data. The delay, power loss, Doppler fading frequency, and lifetime distribution models for static and dynamic vehicle platforms are established and compared, and the effects of the satellite orbit type and platform speed on the models are analyzed. The results reveal the detailed distribution and variation characteristics of the multipath parameters and are valuable for the development of accurate urban navigation systems.

Timing advanced estimation algorithm of low complexity based on DFT spectrum analysis for satellite system

2015 ◽  
Vol 12 (4) ◽  
pp. 140-150 ◽  
Author(s):  
He Yizhou ◽  
Cui Gaofeng ◽  
Li Pengxu ◽  
Chang Ruijun ◽  
Wang Weidong
Keyword(s):  
Spectrum Analysis ◽  
Estimation Algorithm ◽  
Low Complexity ◽  
Satellite System

scholarly journals An Advanced Multipath Mitigation Method Based on Trend Surface Analysis

2020 ◽  
Vol 12 (21) ◽  
pp. 3601
Author(s):  
Zhiren Wang ◽  
Wen Chen ◽  
Danan Dong ◽  
Chenglong Zhang ◽  
Yu Peng ◽  
...  
Keyword(s):  
Surface Analysis ◽  
Low Cost ◽  
Correction Method ◽  
Satellite System ◽  
Double Difference ◽  
Trend Surface Analysis ◽  
Multipath Mitigation ◽  
Trend Surface ◽  
Noise Interference ◽  
Grid Points

Among various ways to eliminate the multipath effect in high-precision global navigation satellite system positioning, the multipath hemispherical map (MHM) is a typical multipath correction method based on spatial domain repeatability, which is suitable for not only static environments, but also some dynamic carriers, such as ships and aircraft. So, it has notable advantages and is widely used. The MHM method divides the sky into grids according to the azimuth and elevation angles of satellite, and calculates the average of the residuals within the grid points as its multipath calibration value. It is easy to implement, but it will inevitably lead to excessive or insufficient multipath correction in the grid. The trend surface analysis-based multipath hemispherical map (T-MHM) method makes up for this deficiency by performing trend surface analysis on the multipath spatial changes within the grid points. However, the effectiveness of T-MHM is limited and less capable of resisting noise interference due to the multicollinearity between the independent variables caused by the special spatial distribution of multipath sampling and the overfitting problem caused by ignoring the multipath anisotropy. Thus, we proposed an improved multipath elimination method named AT-MHM (advanced trend surface analysis-based multipath hemispherical model), which cautiously judges the occurrence of the above problems and gives corresponding solutions. This was extended to double-difference mode, which expands the scope of application. The performance of AT-MHM in GPS pseudorange multipath mitigation was verified on geodetic receiver and low-cost receiver in a strong multipath environment with high occlusion.

scholarly journals PRELIMINARY ANALYSES OF BEIDOU SIGNAL-IN-SPACE ANOMALY SINCE 2013

2016 ◽  
Vol XLI-B1 ◽  
pp. 517-523 ◽  
Author(s):  
Y. Wu ◽  
J. Ren ◽  
W. Liu
Keyword(s):  
Global Navigation Satellite System ◽  
Space Vehicle ◽  
Estimation Algorithm ◽  
Satellite System ◽  
Ground Control ◽  
Navigation Satellite ◽  
Receiver Autonomous Integrity Monitoring ◽  
Global Navigation Satellite ◽  
System Knowledge ◽  
Advanced Receiver

As BeiDou navigation system has been operational since December 2012. There is an increasing desire to use multiple constellation to improve positioning performance. The signal-in-space (SIS) anomaly caused by the ground control and the space vehicle is one of the major threats to affect the integrity. For a young Global Navigation Satellite System, knowledge about SIS anomalies in history is very important for not only assessing the SIS integrity performance of a constellation but also providing the assumption for ARAIM (Advanced Receiver Autonomous Integrity Monitoring). <br><br> In this paper, the broadcast ephemerides and the precise ones are pre-processed for avoiding the false anomaly identification. The SIS errors over the period of Mar. 2013-Feb. 2016 are computed by comparing the broadcast ephemerides with the precise ones. The time offsets between GPST (GPS time) and BDT (BeiDou time) are estimated and removed by an improved estimation algorithm. SIS worst-UREs are computed and a RMS criteria are investigated to identify the SIS anomalies. The results show that the probability of BeiDou SIS anomalies is in 10-3 level in last three years. Even though BeiDou SIS integrity performance currently cannot match the GPS integrity performances, the result indicates that BeiDou has a tendency to improve its integrity performance.

scholarly journals Low-Cost Real-Time PPP/INS Integration for Automated Land Vehicles

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4896 ◽  
Author(s):  
Mohamed Elsheikh ◽  
Walid Abdelfatah ◽  
Aboelmagd Nourledin ◽  
Umar Iqbal ◽  
Michael Korenberg
Keyword(s):  
Real Time ◽  
Low Cost ◽  
Estimation Algorithm ◽  
Satellite System ◽  
Single Frequency ◽  
The Road ◽  
Land Vehicles ◽  
On The Road ◽  
Vehicle Automation ◽  
Global Navigation Satellite

The last decade has witnessed a growing demand for precise positioning in many applications including car navigation. Navigating automated land vehicles requires at least sub-meter level positioning accuracy with the lowest possible cost. The Global Navigation Satellite System (GNSS) Single-Frequency Precise Point Positioning (SF-PPP) is capable of achieving sub-meter level accuracy in benign GNSS conditions using low-cost GNSS receivers. However, SF-PPP alone cannot be employed for land vehicles due to frequent signal degradation and blockage. In this paper, real-time SF-PPP is integrated with a low-cost consumer-grade Inertial Navigation System (INS) to provide a continuous and precise navigation solution. The PPP accuracy and the applied estimation algorithm contributed to reducing the effects of INS errors. The system was evaluated through two road tests which included open-sky, suburban, momentary outages, and complete GNSS outage conditions. The results showed that the developed PPP/INS system maintained horizontal sub-meter Root Mean Square (RMS) accuracy in open-sky and suburban environments. Moreover, the PPP/INS system could provide a continuous real-time positioning solution within the lane the vehicle is moving in. This lane-level accuracy was preserved even when passing under bridges and overpasses on the road. The developed PPP/INS system is expected to benefit low-cost precise land vehicle navigation applications including level 2 of vehicle automation which comprises services such as lane departure warning and lane-keeping assistance.

scholarly journals Precise Point Positioning Algorithm for Pseudolite Combined with GNSS in a Constrained Observation Environment

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1120 ◽  
Author(s):  
Chuanzhen Sheng ◽  
Xingli Gan ◽  
Baoguo Yu ◽  
Jingkui Zhang
Keyword(s):  
High Precision ◽  
Global Navigation Satellite System ◽  
Low Cost ◽  
Estimation Algorithm ◽  
Satellite System ◽  
Navigation Satellite ◽  
Global Navigation ◽  
Point Positioning ◽  
Global Navigation Satellite ◽  
Better Than

In urban canyon environments, Global Navigation Satellite System (GNSS) satellites are heavily obstructed with frequent rise and fall and severe multi-path errors induced by signal reflection, making it difficult to acquire precise, continuous, and reliable positioning information. To meet imperative demands for high-precision positioning of public users in complex environments, like urban canyons, and to solve the problems for GNSS/pseudolite positioning under these circumstances, the Global Navigation Satellite System (GNSS) Precision Point Positioning (PPP) algorithm combined with a pseudolite (PLS) was introduced. The former problems with the pseudolite PPP technique with distributed pseudo-satellites, which relies heavily on known points for initiation and prerequisite for previous high-precision time synchronization, were solved by means of a real-time equivalent clock error estimation algorithm, ambiguity fixing, and validation method. Experiments based on a low-cost receiver were performed, and the results show that in a weak obstructed environment with low-density building where the number of GNSS satellites was greater than seven, the accuracy of pseudolite/GNSS PPP with fixed ambiguity was better than 0.15 m; when there were less than four GNSS satellites in severely obstructed circumstances, it was impossible to obtain position by GNSS alone, but with the support of a pseudolite, the accuracy of PPP was able to be better than 0.3 m. Even without GNSS, the accuracy of PPP could be better than 0.5 m with only four pseudolites. The pseudolite/GNSS PPP algorithm presented in this paper can effectively improve availability with less GNSS or even without GNSS in constrained environments, like urban canyons in cities.

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