scholarly journals Robust Inter-Vehicle Distance Measurement Using Cooperative Vehicle Localization

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2048
Author(s):  
Faan Wang ◽  
Weichao Zhuang ◽  
Guodong Yin ◽  
Shuaipeng Liu ◽  
Ying Liu ◽  
...  
Keyword(s):  
Satellite System ◽  
Superior Performance ◽  
Estimation Methods ◽  
Cooperative Localization ◽  
Absolute Position ◽  
Localization Accuracy ◽  
Vehicle Localization ◽  
Communication Devices ◽  
Positioning Method ◽  
Global Navigation Satellite

Precise localization is critical to safety for connected and automated vehicles (CAV). The global navigation satellite system is the most common vehicle positioning method and has been widely studied to improve localization accuracy. In addition to single-vehicle localization, some recently developed CAV applications require accurate measurement of the inter-vehicle distance (IVD). Thus, this paper proposes a cooperative localization framework that shares the absolute position or pseudorange by using V2X communication devices to estimate the IVD. Four IVD estimation methods are presented: Absolute Position Differencing (APD), Pseudorange Differencing (PD), Single Differencing (SD) and Double Differencing (DD). Several static and dynamic experiments are conducted to evaluate and compare their measurement accuracy. The results show that the proposed methods may have different performances under different conditions. The DD shows the superior performance among the four methods if the uncorrelated errors are small or negligible (static experiment or dynamic experiment with open-sky conditions). When multi-path errors emerge due to the blocked GPS signal, the PD method using the original pseudorange is more effective because the uncorrelated errors cannot be eliminated by the differential technique.

Vehicle Localization Based on Global Navigation Satellite System Aided by Three-Dimensional Map

2017 ◽  
Vol 2621 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Yanlei Gu ◽  
Li-Ta Hsu ◽  
Shunsuke Kamijo
Keyword(s):  
Inertial Sensors ◽  
Three Dimensional ◽  
Satellite System ◽  
Navigation Satellite ◽  
Positioning Accuracy ◽  
Vehicle Localization ◽  
Localization System ◽  
Gnss Positioning ◽  
Positioning Method ◽  
Global Navigation Satellite

Accurate vehicle localization technologies are significant for current onboard navigation systems and future autonomous vehicles. More specifically, positioning accuracy is expected at the submeter level. This paper presents an accurate vehicle self-localization system and evaluates the proposed system in different classes of urban environments. The developed system adopts an innovative global navigation satellite system (GNSS) positioning method as the key technique. The GNSS positioning method can improve the positioning error by reducing the effects of multipath interference and non-line-of-sight errors with the aid of a three-dimensional map. To improve positioning accuracy further, the vehicle localization system integrates the GNSS positioning technique with inertial sensors and vision sensors by considering the characteristics of each sensor. The inertial sensors represent vehicle movement with heading direction and vehicle speed. The vision sensor is used to recognize the position change relative to lane markings on the road surface. Those techniques and sensors collaborate to provide an accurate position in the global coordinate system. To verify the effectiveness and stability of the proposed system, a series of tests was conducted in one of the most challenging urban cities, Tokyo. The experiment results demonstrate that the proposed system can achieve submeter accuracy for the positioning error mean and has a 90% correct lane rate in the localization.

scholarly journals Opportunistic In-Flight INS Alignment Using LEO Satellites and a Rotatory IMU Platform

Aerospace ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 280
Author(s):  
Farzan Farhangian ◽  
Hamza Benzerrouk ◽  
Rene Landry
Keyword(s):  
Kalman Filter ◽  
State Space Model ◽  
Flight Test ◽  
Satellite System ◽  
Low Earth Orbit ◽  
Measurement Unit ◽  
Starting Point ◽  
Leo Satellites ◽  
Positioning Method ◽  
Global Navigation Satellite

With the emergence of numerous low Earth orbit (LEO) satellite constellations such as Iridium-Next, Globalstar, Orbcomm, Starlink, and OneWeb, the idea of considering their downlink signals as a source of pseudorange and pseudorange rate measurements has become incredibly attractive to the community. LEO satellites could be a reliable alternative for environments or situations in which the global navigation satellite system (GNSS) is blocked or inaccessible. In this article, we present a novel in-flight alignment method for a strapdown inertial navigation system (SINS) using Doppler shift measurements obtained from single or multi-constellation LEO satellites and a rotation technique applied on the inertial measurement unit (IMU). Firstly, a regular Doppler positioning algorithm based on the extended Kalman filter (EKF) calculates states of the receiver. This system is considered as a slave block. In parallel, a master INS estimates the position, velocity, and attitude of the system. Secondly, the linearized state space model of the INS errors is formulated. The alignment model accounts for obtaining the errors of the INS by a Kalman filter. The measurements of this system are the difference in the outputs from the master and slave systems. Thirdly, as the observability rank of the system is not sufficient for estimating all the parameters, a discrete dual-axis IMU rotation sequence was simulated. By increasing the observability rank of the system, all the states were estimated. Two experiments were performed with different overhead satellites and numbers of constellations: one for a ground vehicle and another for a small flight vehicle. Finally, the results showed a significant improvement compared to stand-alone INS and the regular Doppler positioning method. The error of the ground test reached around 26 m. This error for the flight test was demonstrated in different time intervals from the starting point of the trajectory. The proposed method showed a 180% accuracy improvement compared to the Doppler positioning method for up to 4.5 min after blocking the GNSS.

scholarly journals An Integrated Positioning and Attitude Determination System for Immersed Tunnel Elements: A Simulation Study

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7296
Author(s):  
Guanqing Li ◽  
Lasse Klingbeil ◽  
Florian Zimmermann ◽  
Shengxiang Huang ◽  
Heiner Kuhlmann
Keyword(s):  
Sound Speed ◽  
Attitude Determination ◽  
Satellite System ◽  
Sufficient Accuracy ◽  
Navigation Satellite ◽  
Accuracy Analysis ◽  
Absolute Position ◽  
Immersed Tunnel ◽  
Determination System ◽  
Global Navigation Satellite

Immersed tunnel elements need to be exactly controlled during their immersion process. Position and attitude of the element should be determined quickly and accurately to navigate the element from the holding area to the final location in the tunnel trench. In this paper, a newly-developed positioning and attitude determination system, integrating a 3-antenna Global Navigation Satellite System (GNSS) system, an inclinometer and a range-measurement system, is presented. The system is designed to provide the absolute position of both ends of the element with sufficient accuracy in real time. Special attention in the accuracy analysis is paid to the influence of GNSS multipath error and sound speed profile. Simulations are conducted to illustrate the performance of the system in different scenarios. If both elements are very close, the accuracies of the system are higher than 0.02 m in the directions perpendicular to and along the tunnel axis.

The Research of Multipath and Linear Error for Pseudolites Applications

2011 ◽  
Vol 130-134 ◽  
pp. 2890-2893 ◽  
Author(s):  
Xiao Guang Wan ◽  
Xing Qun Zhan
Keyword(s):  
Carrier Phase ◽  
Indoor Environment ◽  
Phase Measurement ◽  
Satellite System ◽  
Independent System ◽  
Carrier Phase Measurement ◽  
Wide Range ◽  
Positioning Method ◽  
Global Navigation Satellite ◽  
Is Design

Pseudolites are ground-based transmitters that send global navigation satellite system like signals, such as GPS, GLONASS, or Galileo. As an independent system for indoor positioning, pseudolites technique can be explored for a wide range of positioning and navigation application where the signal of satellite GNSS can’t be received. However, with indoor environment, the positioning method of pseudolite navigation system is not entirely same as GNSS, and there are some challenging issues in research and system design. In this paper, a signal difference carrier phase measurement system with pseudolites is design. Furthermore, two major problems are studied that they are multipath error and linear errors.

scholarly journals Integrity Monitoring of PPP-RTK Positioning; Part I: GNSS-Based IM Procedure

2021 ◽  
Vol 14 (1) ◽  
pp. 44
Author(s):  
Kan Wang ◽  
Ahmed El-Mowafy ◽  
Weijin Qin ◽  
Xuhai Yang
Keyword(s):  
Road Transport ◽  
Satellite System ◽  
Convergence Time ◽  
Transport Systems ◽  
Navigation Satellite ◽  
Integrity Monitoring ◽  
Network Scale ◽  
Positioning Method ◽  
Multipath Environment ◽  
Global Navigation Satellite

Nowadays, integrity monitoring (IM) is required for diverse safety-related applications using intelligent transport systems (ITS). To ensure high availability for road transport users for in-lane positioning, a sub-meter horizontal protection level (HPL) is expected, which normally requires a much higher horizontal positioning precision of, e.g., a few centimeters. Precise point positioning-real-time kinematic (PPP-RTK) is a positioning method that could achieve high accuracy without long convergence time and strong dependency on nearby infrastructure. As the first part of a series of papers, this contribution proposes an IM strategy for multi-constellation PPP-RTK positioning based on global navigation satellite system (GNSS) signals. It analytically studies the form of the variance-covariance (V-C) matrix of ionosphere interpolation errors for both accuracy and integrity purposes, which considers the processing noise, the ionosphere activities and the network scale. In addition, this contribution analyzes the impacts of diverse factors on the size and convergence of the HPLs, including the user multipath environment, the ionosphere activity, the network scale and the horizontal probability of misleading information (PMI). It is found that the user multipath environment generally has the largest influence on the size of the converged HPLs, while the ionosphere interpolation and the multipath environments have joint impacts on the convergence of the HPL. Making use of 1 Hz data of Global Positioning System (GPS)/Galileo/Beidou Navigation Satellite System (BDS) signals on L1 and L5 frequencies, for small- to mid-scaled networks, under nominal multipath environments and for a horizontal PMI down to , the ambiguity-float HPLs can converge to 1.5 m within or around 50 epochs under quiet to medium ionosphere activities. Under nominal multipath conditions for small- to mid-scaled networks, with the partial ambiguity resolution enabled, the HPLs can converge to 0.3 m within 10 epochs even under active ionosphere activities.

scholarly journals Performance Evaluation of Pedestrian Locations Based on Contemporary Smartphones

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Jalal Ibrahim Al-Azizi ◽  
Helmi Zulhaidi Mohd Shafri
Keyword(s):  
Performance Evaluation ◽  
Environmental Factors ◽  
Global Navigation Satellite System ◽  
Low Cost ◽  
Satellite System ◽  
Navigation Satellite ◽  
Localization Accuracy ◽  
Environment Type ◽  
Global Navigation ◽  
Global Navigation Satellite

Nowadays, a Global Navigation Satellite System (GNSS) unit is embedded in nearly every smartphone. This unit allows a smartphone to detect the user’s location and motion, and it makes functions, such as navigation, tracking, and compass applications, available to the user. Therefore, the GNSS unit has become one of the most important features in modern smartphones. However, because most smartphones incorporate relatively low-cost GNSS chips, their localization accuracy varies depending on the number of accessible GNSS satellites, and it is highly dependent on environmental factors that cause interference such as forests and buildings. This research evaluated the performance of the GNSS units inside two different models of smartphones in determining pedestrian locations in different environments. The results indicate that the overall performances of the two devices were related directly to the environment, type of smartphone/GNSS chipset, and the application used to collect the information.

scholarly journals Direct Aerial Visual Geolocalization Using Deep Neural Networks

2021 ◽  
Vol 13 (19) ◽  
pp. 4017
Author(s):  
Winthrop Harvey ◽  
Chase Rainwater ◽  
Jackson Cothren
Keyword(s):  
Neural Networks ◽  
Deep Neural Networks ◽  
Ground Level ◽  
Satellite System ◽  
Input Image ◽  
Average Error ◽  
Washington County ◽  
Localization Accuracy ◽  
Landscape Information ◽  
Global Navigation Satellite

Unmanned aerial vehicles (UAVs) must keep track of their location in order to maintain flight plans. Currently, this task is almost entirely performed by a combination of Inertial Measurement Units (IMUs) and reference to GNSS (Global Navigation Satellite System). Navigation by GNSS, however, is not always reliable, due to various causes both natural (reflection and blockage from objects, technical fault, inclement weather) and artificial (GPS spoofing and denial). In such GPS-denied situations, it is desirable to have additional methods for aerial geolocalization. One such method is visual geolocalization, where aircraft use their ground facing cameras to localize and navigate. The state of the art in many ground-level image processing tasks involve the use of Convolutional Neural Networks (CNNs). We present here a study of how effectively a modern CNN designed for visual classification can be applied to the problem of Absolute Visual Geolocalization (AVL, localization without a prior location estimate). An Xception based architecture is trained from scratch over a >1000 km2 section of Washington County, Arkansas to directly regress latitude and longitude from images from different orthorectified high-altitude survey flights. It achieves average localization accuracy on unseen image sets over the same region from different years and seasons with as low as 115 meters average error, which localizes to 0.004% of the training area, or about 8% of the width of the 1.5 × 1.5km input image. This demonstrates that CNNs are expressive enough to encode robust landscape information for geolocalization over large geographic areas. Furthermore, discussed are methods of providing uncertainty for CNN regression outputs, and future areas of potential improvement for use of deep neural networks in visual geolocalization.

scholarly journals Rail Vehicle Localization Exploiting Rail Track Georeferenced Coordinates

2015 ◽  
Vol 1 (2) ◽  
pp. 1-12
Author(s):  
António João Ferreira ◽  
José Miguel Almeida ◽  
Eduardo Silva
Keyword(s):  
Dead Reckoning ◽  
Satellite System ◽  
Vehicle Localization ◽  
Rail Vehicle ◽  
Position Errors ◽  
Railroad Tracks ◽  
Rail Vehicles ◽  
Global Navigation Satellite ◽  
Global Uncertainty

A novel dead reckoning algorithm conceived for localization of small inspection rail vehicles in Global Navigation Satellite System (GNSS) denied environments is presented. This work focus on simplifying the rail vehicle localization task, taking into account restrictions on movement imposed by the railroad tracks. Considering that dead reckoning techniques accumulate errors over time, leading to increasing global uncertainty, a method was designed to correct the estimates and also smooth trajectory errors backwards in time, through visualization of global landmarks. Results show the effectiveness of this approach in reducing long-term position errors. The current document reports real railroad experiments, featuring a specially designed non-motorized mobile modeling vehicle.

scholarly journals The Triangulation Reduction Analysis of Acute Triangle

2019 ◽  
Author(s):  
Fauzi Janu Amarrohman ◽  
L M Sabri ◽  
Moehammad Awaluddin ◽  
Bambang Darmo Yuwono
Keyword(s):  
Reference Value ◽  
Satellite System ◽  
Navigation Satellite ◽  
Total Station ◽  
The Earth ◽  
Positioning Method ◽  
Plane Projection ◽  
Acute Triangle ◽  
Global Navigation Satellite ◽  
Different Levels

Positioning on the surface of the earth using the triangulation method can be done in two ways, namely terrestrial method for example by measuring the angle and distance using the total station tool and extraterrestrial methods for example by using satellite-based positioning technology. Extraterrestrial positioning method using the global navigation satellite system combined with terrestrial methods by measuring angles and distances using the total station tool is one alternative to positioning well. In this study position determination will only be calculated using two intermediate calculation plane, on the ellipsoid projection and in the plane projection. Of course, in a process of measuring position for the same point but using different methods it will produce different levels of accuracy. From the results of the comparison in determining the definitive coordinate value generated by the count on the ellipsoid projection with the Gauss-Helmert method, the definitive value that is closer to the reference value measured by static measurements methods rather than definitive coordinates produced through calculations in the plane projection.

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