80 research outputs found
Towards Full Automated Drive in Urban Environments: A Demonstration in GoMentum Station, California
Each year, millions of motor vehicle traffic accidents all over the world
cause a large number of fatalities, injuries and significant material loss.
Automated Driving (AD) has potential to drastically reduce such accidents. In
this work, we focus on the technical challenges that arise from AD in urban
environments. We present the overall architecture of an AD system and describe
in detail the perception and planning modules. The AD system, built on a
modified Acura RLX, was demonstrated in a course in GoMentum Station in
California. We demonstrated autonomous handling of 4 scenarios: traffic lights,
cross-traffic at intersections, construction zones and pedestrians. The AD
vehicle displayed safe behavior and performed consistently in repeated
demonstrations with slight variations in conditions. Overall, we completed 44
runs, encompassing 110km of automated driving with only 3 cases where the
driver intervened the control of the vehicle, mostly due to error in GPS
positioning. Our demonstration showed that robust and consistent behavior in
urban scenarios is possible, yet more investigation is necessary for full scale
roll-out on public roads.Comment: Accepted to Intelligent Vehicles Conference (IV 2017
MmWave System for Future ITS:A MAC-layer Approach for V2X Beam Steering
Millimeter Waves (mmWave) systems have the potential of enabling
multi-gigabit-per-second communications in future Intelligent Transportation
Systems (ITSs). Unfortunately, because of the increased vehicular mobility,
they require frequent antenna beam realignments - thus significantly increasing
the in-band Beamforming (BF) overhead. In this paper, we propose Smart
Motion-prediction Beam Alignment (SAMBA), a MAC-layer algorithm that exploits
the information broadcast via DSRC beacons by all vehicles. Based on this
information, overhead-free BF is achieved by estimating the position of the
vehicle and predicting its motion. Moreover, adapting the beamwidth with
respect to the estimated position can further enhance the performance. Our
investigation shows that SAMBA outperforms the IEEE 802.11ad BF strategy,
increasing the data rate by more than twice for sparse vehicle density while
enhancing the network throughput proportionally to the number of vehicles.
Furthermore, SAMBA was proven to be more efficient compared to legacy BF
algorithm under highly dynamic vehicular environments and hence, a viable
solution for future ITS services.Comment: Accepted for publication in IEEE VTC Fall 2017 conference proceeding
Driver Digital Twin for Online Prediction of Personalized Lane Change Behavior
Connected and automated vehicles (CAVs) are supposed to share the road with
human-driven vehicles (HDVs) in a foreseeable future. Therefore, considering
the mixed traffic environment is more pragmatic, as the well-planned operation
of CAVs may be interrupted by HDVs. In the circumstance that human behaviors
have significant impacts, CAVs need to understand HDV behaviors to make safe
actions. In this study, we develop a Driver Digital Twin (DDT) for the online
prediction of personalized lane change behavior, allowing CAVs to predict
surrounding vehicles' behaviors with the help of the digital twin technology.
DDT is deployed on a vehicle-edge-cloud architecture, where the cloud server
models the driver behavior for each HDV based on the historical naturalistic
driving data, while the edge server processes the real-time data from each
driver with his/her digital twin on the cloud to predict the lane change
maneuver. The proposed system is first evaluated on a human-in-the-loop
co-simulation platform, and then in a field implementation with three passenger
vehicles connected through the 4G/LTE cellular network. The lane change
intention can be recognized in 6 seconds on average before the vehicle crosses
the lane separation line, and the Mean Euclidean Distance between the predicted
trajectory and GPS ground truth is 1.03 meters within a 4-second prediction
window. Compared to the general model, using a personalized model can improve
prediction accuracy by 27.8%. The demonstration video of the proposed system
can be watched at https://youtu.be/5cbsabgIOdM
Implicit Cooperative Positioning in Vehicular Networks
Absolute positioning of vehicles is based on Global Navigation Satellite
Systems (GNSS) combined with on-board sensors and high-resolution maps. In
Cooperative Intelligent Transportation Systems (C-ITS), the positioning
performance can be augmented by means of vehicular networks that enable
vehicles to share location-related information. This paper presents an Implicit
Cooperative Positioning (ICP) algorithm that exploits the Vehicle-to-Vehicle
(V2V) connectivity in an innovative manner, avoiding the use of explicit V2V
measurements such as ranging. In the ICP approach, vehicles jointly localize
non-cooperative physical features (such as people, traffic lights or inactive
cars) in the surrounding areas, and use them as common noisy reference points
to refine their location estimates. Information on sensed features are fused
through V2V links by a consensus procedure, nested within a message passing
algorithm, to enhance the vehicle localization accuracy. As positioning does
not rely on explicit ranging information between vehicles, the proposed ICP
method is amenable to implementation with off-the-shelf vehicular communication
hardware. The localization algorithm is validated in different traffic
scenarios, including a crossroad area with heterogeneous conditions in terms of
feature density and V2V connectivity, as well as a real urban area by using
Simulation of Urban MObility (SUMO) for traffic data generation. Performance
results show that the proposed ICP method can significantly improve the vehicle
location accuracy compared to the stand-alone GNSS, especially in harsh
environments, such as in urban canyons, where the GNSS signal is highly
degraded or denied.Comment: 15 pages, 10 figures, in review, 201
A dynamic two-dimensional (D2D) weight-based map-matching algorithm
Existing map-Matching (MM) algorithms primarily localize positioning fixes along the centerline of a road and have largely ignored road width as an input. Consequently, vehicle lane-level localization, which is essential for stringent Intelligent Transport System (ITS) applications, seems difficult to accomplish, especially with the positioning data from low-cost GPS sensors. This paper aims to address this limitation by developing a new dynamic two-dimensional (D2D) weight-based MM algorithm incorporating dynamic weight coefficients and road width. To enable vehicle lane-level localization, a road segment is virtually expressed as a matrix of homogeneous grids with reference to a road centerline. These grids are then used to map-match positioning fixes as opposed to matching on a road centerline as carried out in traditional MM algorithms. In this developed algorithm, vehicle location identification on a road segment is based on the total weight score which is a function of four different weights: (i) proximity, (ii) kinematic, (iii) turn-intent prediction, and (iv) connectivity. Different parameters representing network complexity and positioning quality are used to assign the relative importance to different weight scores by employing an adaptive regression method. To demonstrate the transferability of the developed algorithm, it was tested by using 5,830 GPS positioning points collected in Nottingham, UK and 7,414 GPS positioning points collected in Mumbai and Pune, India. The developed algorithm, using stand-alone GPS position fixes, identifies the correct links 96.1% (for the Nottingham data) and 98.4% (for the Mumbai-Pune data) of the time. In terms of the correct lane identification, the algorithm was found to provide the accurate matching for 84% (Nottingham) and 79% (Mumbai-Pune) of the fixes obtained by stand-alone GPS. Using the same methodology adopted in this study, the accuracy of the lane identification could further be enhanced if the localization data from additional sensors (e.g. gyroscope) are utilized. ITS industry and vehicle manufacturers can implement this D2D map-matching algorithm for liability critical and in-vehicle information systems and services such as advanced driver assistant systems (ADAS)
Infrastructure Wi-Fi for connected autonomous vehicle positioning : a review of the state-of-the-art
In order to realize intelligent vehicular transport networks and self driving cars, connected autonomous vehicles (CAVs) are required to be able to estimate their position to the nearest centimeter. Traditional positioning in CAVs is realized by using a global navigation satellite system (GNSS) such as global positioning system (GPS) or by fusing weighted location parameters from a GNSS with an inertial navigation systems (INSs). In urban environments where Wi-Fi coverage is ubiquitous and GNSS signals experience signal blockage, multipath or non line-of-sight (NLOS) propagation, enterprise or carrier-grade Wi-Fi networks can be opportunistically used for localization or “fused” with GNSS to improve the localization accuracy and precision. While GNSS-free localization systems are in the literature, a survey of vehicle localization from the perspective of a Wi-Fi anchor/infrastructure is limited. Consequently, this review seeks to investigate recent technological advances relating to positioning techniques between an ego vehicle and a vehicular network infrastructure. Also discussed in this paper is an analysis of the location accuracy, complexity and applicability of surveyed literature with respect to intelligent transportation system requirements for CAVs. It is envisaged that hybrid vehicular localization systems will enable pervasive localization services for CAVs as they travel through urban canyons, dense foliage or multi-story car parks
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