scholarly journals Positioning Using IRIDIUM Satellite Signals of Opportunity in Weak Signal Environment

Electronics ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 37 ◽  
Author(s):  
Zizhong Tan ◽  
Honglei Qin ◽  
Li Cong ◽  
Chao Zhao
Keyword(s):  
Estimation Algorithm ◽  
Satellite System ◽  
Positioning System ◽  
Weak Signal ◽  
Open Environment ◽  
Signal Characteristics ◽  
Signal Environment ◽  
Positioning Technique ◽  
Global Navigation Satellite ◽  
Signals Of Opportunity

In order to get rid of the dependence of the navigation and positioning system on the global navigation satellite system (GNSS), radio, television, satellite, and other signals of opportunity (SOPs) can be used to achieve receiver positioning. The space-based SOPs based on satellites offer better coverage and availability than ground-based SOPs. Based on the related research of Iridium SOPs positioning in the open environment, this paper mainly focuses on the occluded environment and studies the Iridium SOPs positioning technique in weak signal environment. A new quadratic square accumulating instantaneous Doppler estimation algorithm (QSA-IDE) is proposed after analysing the orbit and signal characteristics of the Iridium satellite. The new method can improve the ability of the Iridium weak signal Doppler estimation. The theoretical analysis and positioning results based on real signal data show that the positioning based on Iridium SOPs can be realized in a weak signal environment. The research broadens the applicable environment of the Iridium SOPs positioning, thereby improving the availability and continuity of its positioning.

Ranging technology using signals of opportunity of non-cooperative communication satellites

2020 ◽  
pp. 1-13
Author(s):  
Yuanyuan Gao ◽  
Yu Hua ◽  
Yu Xiang ◽  
Changjiang Huang ◽  
Shanhe Wang ◽  
...  
Keyword(s):  
Cooperative Communication ◽  
Estimation Algorithm ◽  
Time Difference ◽  
Difference Measurement ◽  
Test Platform ◽  
Positioning Technique ◽  
And Performance ◽  
Navigation Signals ◽  
To Receive ◽  
Signals Of Opportunity

Abstract The positioning technique employing the ubiquitous signals of opportunity of non-cooperative satellites does not send special navigation signals, instead it passively receives satellite signals as noise, presenting advantages of concealment and difficulty for potential attackers. Thus, this study investigates the ranging principle and model using non-cooperative communication satellites and a time difference estimation algorithm. The technology of time difference measurement under non-cooperative observation mode was determined and simulated. A test platform for time difference measurement was built to receive the signal from an unknown geostationary Earth orbit communication satellite and verify the ranging feasibility and performance. The ranging accuracy was found to be smaller than 6 m, as demonstrated by experimental data, which shows the viability of the proposed positioning technique for ranging technology.

scholarly journals C/N0 Estimator Based on the Adaptive Strong Tracking Kalman Filter for GNSS Vector Receivers

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 739 ◽  
Author(s):  
Shiming Liu ◽  
Sihai Li ◽  
Jiangtao Zheng ◽  
Qiangwen Fu ◽  
Yanhua Yuan
Keyword(s):  
Kalman Filter ◽  
Estimation Method ◽  
Signal Amplitude ◽  
Satellite System ◽  
Static Field ◽  
Weak Signal ◽  
Important Indicator ◽  
Vector Receiver ◽  
Averaging Time ◽  
Global Navigation Satellite

The carrier-to-noise ratio (C/N0) is an important indicator of the signal quality of global navigation satellite system receivers. In a vector receiver, estimating C/N0 using a signal amplitude Kalman filter is a typical method. However, the classical Kalman filter (CKF) has a significant estimation delay if the signal power levels change suddenly. In a weak signal environment, it is difficult to estimate the measurement noise for CKF correctly. This article proposes the use of the adaptive strong tracking Kalman filter (ASTKF) to estimate C/N0. The estimator was evaluated via simulation experiments and a static field test. The results demonstrate that the ASTKF C/N0 estimator can track abrupt variations in C/N0 and the method can estimate the weak signal C/N0 correctly. When C/N0 jumps, the ASTKF estimation method shows a significant advantage over the adaptive Kalman filter (AKF) method in terms of the time delay. Compared with the popular C/N0 algorithms, the narrow-to-wideband power ratio (NWPR) method, and the variance summing method (VSM), the ASTKF C/N0 estimator can adopt a shorter averaging time, which reduces the hysteresis of the estimation results.

scholarly journals Locata Network Design and Reliability Analysis for Harbour Positioning

2014 ◽  
Vol 68 (2) ◽  
pp. 238-252 ◽  
Author(s):  
Ling Yang ◽  
Yong Li ◽  
Wei Jiang ◽  
Chris Rizos
Keyword(s):  
Failure Modes ◽  
Satellite System ◽  
Fault Identification ◽  
Positioning System ◽  
Algorithm Performance ◽  
Protection Level ◽  
Receiver Autonomous Integrity Monitoring ◽  
Global Navigation Satellite ◽  
Port Areas

To meet the accuracy, integrity, continuity and availability required for many navigation applications the Locata technology can provide an alternative to satellite-based navigation in difficult Global Navigation Satellite System (GNSS) signal environments, especially for applications in port areas and in constricted waterways. Unlike GNSS constellations, a LocataNet – a local constellation of LocataLites – can be designed specifically for different environments to avoid signal blockages, interference or poor geometry. By using Locata technology, the optimal performance within particular areas can always be guaranteed. This paper demonstrates the influence of LocataNet configuration on the reliability and integrity of the Locata positioning system. The performance of the Locata system is investigated using the Receiver Autonomous Integrity Monitoring (RAIM) concept. Fault Detection and Exclusion (FDE) algorithm performance is validated through the computation of the Dilution of Precision (DOP), the Horizontal Protection Level (HPL) and the correlation coefficient between two failure modes that can indicate the quality of fault identification. The experimental analysis shows that a good configuration of LocataLites will enhance the accuracy and reliability of the navigation system.

Urban Fleet Monitoring with GPS and GLONASS

1998 ◽  
Vol 51 (3) ◽  
pp. 382-393 ◽  
Author(s):  
M. Tsakiri ◽  
M. Stewart ◽  
T. Forward ◽  
D. Sandison ◽  
J. Walker
Keyword(s):  
Global Positioning System ◽  
Public Transport ◽  
Urban Areas ◽  
Dead Reckoning ◽  
Satellite System ◽  
Basic Function ◽  
Positioning System ◽  
Positioning Systems ◽  
Global Positioning ◽  
Global Navigation Satellite

The increasing volume of traffic in urban areas has resulted in steady growth of the mean driving time on fixed routes. Longer driving times lead to significantly higher transportation costs, particularly for vehicle fleets, where efficiency in the distribution of their transport tasks is important in staying competitive in the market. For bus fleets, the optimal control and command of the vehicles is, as well as the economic requirements, a basic function of their general mission. The Global Positioning System (GPS) allows reliable and accurate positioning of public transport vehicles except within the physical limitations imposed by built-up city ‘urban canyons’. With a view to the next generation of satellite positioning systems for public transport fleet management, this paper highlights the limitations imposed on current GPS systems operating in the urban canyon. The capabilities of a future positioning system operating in this type of environment are discussed. It is suggested that such a system could comprise receivers capable of integrating the Global Positioning System (GPS) and the Russian equivalent, the Global Navigation Satellite System (GLONASS), and relatively cheap dead-reckoning sensors.

Accounting for Inter-System Bias in DGNSS Positioning with GPS/GLONASS/BDS/Galileo

2017 ◽  
Vol 70 (4) ◽  
pp. 686-698 ◽  
Author(s):  
Hui Liu ◽  
Bao Shu ◽  
Longwei Xu ◽  
Chuang Qian ◽  
Rufei Zhang ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Simple Algorithm ◽  
Satellite System ◽  
Harsh Environments ◽  
Positioning System ◽  
Gnss Positioning ◽  
Global Positioning ◽  
System Bias ◽  
Global Navigation Satellite ◽  
Reliability And Availability

Code Differential Global Positioning System (DGPS) is widely used in satellite navigation and positioning because of its simple algorithm and preferable precision. Multi-Global Navigation Satellite System (GNSS) is expected to enhance the accuracy, reliability and availability of Differential GNSS (DGNSS) positioning. Traditional DGNSS models should set separate clock parameters due to the clock differences between the different systems. Awareness of the Inter-System Bias (ISB) could help to maximise the redundancy of the positioning model, thus improving the performance of multi-GNSS positioning. This paper aims to examine the inter-system bias of GPS/GLONASS/BeiDou (BDS)/Galileo and their benefits in DGNSS positioning. Results show that Differential ISB (DISB) characteristics vary with different receiver types and systems. The size of DISB could reach metre-level and the precision of estimated DISBs can reach approximately several centimetres within tens of epochs. Therefore, a new real-time DGNSS model that accounts for ISB is proposed. After differential ISBs are initialised, positioning with four satellites from arbitrarily the same or different systems can be realised. Moreover, compared with the traditional DGNSS model, the precision of the positioning results with the new model are obviously improved, especially in harsh environments.

scholarly journals New Test Facilities For GNSS Testing And Dynamic Calibration

2014 ◽  
Vol 21 (1) ◽  
pp. 151-162 ◽  
Author(s):  
Andreas Trzuskowsky ◽  
Dirk Abel ◽  
Martin Pölöskey ◽  
Carsten Hoelper
Keyword(s):  
Global Navigation Satellite System ◽  
Satellite System ◽  
Dynamic Calibration ◽  
Positioning System ◽  
Navigation Satellite ◽  
Open Area ◽  
Multiple Test ◽  
Maximum Benefit ◽  
Global Navigation ◽  
Global Navigation Satellite

Abstract With Galileo, the European GNSS (Global Navigation Satellite System) starting early services in 2015, open-area-testing of applications which use the new positioning system gets more and more important. This contribution gives an overview on existing test sites like railGATE, automotiveGATE and seaGATE, it highlights the latest addition for dynamic calibration with geodetic precision and finally describes the testing regime of the BONUS project ANCHOR, where multiple test sites are used for maximum benefit in a maritime application.

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 Assessment of the Steering Precision of a Hydrographic USV along Sounding Profiles Using a High-Precision GNSS RTK Receiver Supported Autopilot

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5637
Author(s):  
Łukasz Marchel ◽  
Cezary Specht ◽  
Mariusz Specht
Keyword(s):  
High Precision ◽  
Low Cost ◽  
Path Following ◽  
Satellite System ◽  
Magnetic Compass ◽  
Reference Station ◽  
Positioning System ◽  
Positioning Accuracy ◽  
Unmanned Surface Vehicles ◽  
Global Navigation Satellite

Unmanned Surface Vehicles (USV) are increasingly used to perform numerous tasks connected with measurements in inland waters and seas. One of such target applications is hydrography, where traditional (manned) bathymetric measurements are increasingly often realized by unmanned surface vehicles. This pertains especially to restricted or hardly navigable waters, in which execution of hydrographic surveys with the use of USVs requires precise maneuvering. Bathymetric measurements should be realized in a way that makes it possible to determine the waterbody’s depth as precisely as possible, and this requires high-precision in navigating along planned sounding profiles. This paper presents research that aimed to determine the accuracy of unmanned surface vehicle steering in autonomous mode (with a Proportional-Integral-Derivative (PID) controller) along planned hydrographic profiles. During the measurements, a high-precision Global Navigation Satellite System (GNSS) Real Time Kinematic (RTK) positioning system based on a GNSS reference station network (positioning accuracy: 1–2 cm, p = 0.95) and a magnetic compass with the stability of course maintenance of 1°–3° Root Mean Square (RMS) were used. For the purpose of evaluating the accuracy of the vessel’s path following along sounding profiles, the cross track error (XTE) measure, i.e., the distance between an USV’s position and the hydrographic profile, calculated transversely to the course, was proposed. The tests were compared with earlier measurements taken by other unmanned surface vehicles, which followed the exact same profiles with the use of much simpler and low-cost multi-GNSS receiver (positioning accuracy: 2–2.5 m or better, p = 0.50), supported with a Fluxgate magnetic compass with a high course measurement accuracy of 0.3° (p = 0.50 at 30 m/s). The research has shown that despite the considerable difference in the positioning accuracy of both devices and incomparably different costs of both solutions, the authors proved that the use of the GNSS RTK positioning system, as opposed to a multi-GNSS system supported with a Fluxgate magnetic compass, influences the precision of USV following sounding profiles to an insignificant extent.

scholarly journals Dynamic Performance Evaluation of Various GNSS Receivers and Positioning Modes with Only One Flight Test

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1518 ◽  
Author(s):  
Cheolsoon Lim ◽  
Hyojung Yoon ◽  
Am Cho ◽  
Chang-Sun Yoo ◽  
Byungwoon Park
Keyword(s):  
Dynamic Performance ◽  
Dynamic Test ◽  
Flight Test ◽  
Test Session ◽  
Satellite System ◽  
Static Test ◽  
Moving Vehicles ◽  
Gnss Receivers ◽  
Signal Environment ◽  
Global Navigation Satellite

The performance of global navigation satellite system (GNSS) receivers in dynamic modes is mostly assessed using results obtained from independent maneuvering of vehicles along similar trajectories at different times due to limitations of receivers, payload, space, and power of moving vehicles. However, such assessments do not ensure valid evaluation because the same GNSS signal environment cannot be ensured in a different test session irrespective of how accurately it mimics the original session. In this study, we propose a valid methodology that can evaluate the dynamic performance of multiple GNSS receivers in various positioning modes with only one dynamic test. We used the record-and-replay function of RACELOGIC’s LabSat3 Wideband and developed a software that can log and re-broadcast Radio Technical Commission for Maritime Services (RTCM) messages for the augmented systems. A preliminary static test and a drone test were performed to verify proper operation of the system. The results show that the system could efficiently evaluate the performances of stand-alone, differential GNSS, and real time kinematics positioning for three GNSS receivers in two different positioning modes by repeatedly re-radiating the recorded signals acquired through only one flight. Our proposed system is expected to be useful in evaluating dynamic navigation performance accurately and conveniently in a valid manner.

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