Browsing by Subject "Global Positioning System"

Now showing 1 - 17 of 17

Accessibility, Network Structure, and Consumers’ Destination Choice: A GIS Analysis of GPS Travel Data and the CLUSTER Simulation Module for Retail Location Choice
(Intelligent Transportation Systems Institute, Center for Transportation Studies, University of Minnesota, 2012-10) Huang, Arthur; Levinson, David
Anecdotal and empirical evidence has shown strong associations between the built environment and individuals’ travel decision. To date, data about individuals’ travel behavior and the nature of the retail environment have not been linked at the fine-grained level for verifying such relationships. GPS and GIS have revolutionized how we measure and monitor land use and individual travel behavior. Compared with traditional travel survey methods, GPS technologies provide more accurate and detailed information about individuals’ trips. Based the GPS travel data in the Twin Cities we analyze the impact of individuals’ interactions with road network structure and the destinations’ accessibility on individuals’ destination choice for home-based non-work retail trips. The results reveal that higher accessibility and diversity of services make the destination more attractive. Further, accessibility and diversity of establishments in a walking zone are often highly correlated. A destination reached via a more circuitous or discontinuous route dampens its appeal. In addition, we build an agent-based simulation tool to study retail location choice on a supply chain network consisting of suppliers, retailers, and consumers. The simulation software illustrates that the clustering of retailers can emerge from the balance of distance to suppliers and the distance to consumers. We further applied this tool in the Transportation Geography and Networks course (CE 5180) at the University of Minnesota. Student feedback reveals that it is a useful active learning tool for transportation and urban planning education. The software also has the potential of being extended for an integrated regional transportation-land use forecasting model.
Analysis of GPS-based Real Time Attitude Determination System for ITS Application
(Intelligent Transportation Systems Institute, Center for Transportation Studies, University of Minnesota, 2012-11) Gebre-Egziabher, Demoz; Lie, Fidelis Adhika Pradipta
This work describes the development and testing of GPS-based attitude and heading determination system (AHRS) using single-frequency (L1) carrier phase differential GPS (CPDGPS). Vehicle's attitude can be uniquely determined from two non-collinear relative position vectors, known as the baseline vectors. The accuracy of the resulting attitude estimate depends on the accuracy of the baseline vector estimates and their respective magnitudes (length). The shorter the baseline, the higher the vector accuracy required to give the same attitude accuracy that can be obtained through longer baseline system. Issues such as ambiguity resolution and phase center variations are discussed. Test result shows that single-frequency CPDGPS is still a challenge, mainly caused by the integer ambiguity problem inherent to CPDGPS problem. A more feasible but less accurate method using a short baseline is also discussed. Phase center calibration remains a challenge for this attitude determination system.
Analysis of Single Frequency, Carrier Phase Based GPS Positioning Performance and Sensor Aiding Requirements
(Intelligent Transportation Systems Institute, Center for Transportation Studies, University of Minnesota, 2013-01) Gebre-Egziabher, Demoz; Mokhtarzadeh, Hamid
The work described in this report outlines the design and testing of a low-cost, single frequency, carrier phase positioning system. Furthermore, aiding sensor accuracy requirements are analyzed to improve the robustness of the carrier phase system after emerging from signal outages. The applications of interest are ones with safety-of-life implications such as driver assist systems.
Characterizing Phase-Center Motion of GNSS Antennas Used in High-Accuracy Positioning
(Center for Transportation Studies, University of Minnesota, 2019-06) Dave, Aditya; Saborio, Ricardo; Sun, Kerry; Sainati, Robert; Gebre-Egziaher, Demoz; Franklin, Rhonda
Emerging transportation applications require positioning solutions with accuracy of a few centimeters. Current Global Navigation Satellite Systems (GNSS), such as GPS, GLONASS, and Galileo are, in some instances, capable of providing this level of accuracy. Real-Time Kinematic (RTK) techniques can generate solutions accurate to a few centimeters in a given locale. Precise Point Positioning (PPP) techniques promise to deliver RTK-level performance on a global scale. Even though low-cost, RTK-capable GNSS receivers are available today, antennas are a key component affecting quality of the positioning solution. Unless coupled with a high-quality (thus, more expensive) antenna, a low-cost receiver may not provide the centimeter-level accuracy needed for a safety-critical transportation application (e.g., autonomous vehicle, driver assist systems, etc.). Stability of the antenna phase-center is dependent on the antenna quality and can potentially move on the order of tens of mm if not centimeters. The purpose of the work reported here was to characterize the nature of this motion as a function of antenna quality. Anechoic chamber tests were performed using one high-cost and another low-cost GNSS antenna. The selected antennas represented “book ends” on the cost spectrum. These experiments showed that phase-center motion on the low-cost antenna can be a factor of four times larger than on high-quality antennas. Since anechoic chamber tests are not practical for each antenna installation in transportation applications, methods for antenna-specific, in-situ, phase-center motion calibration (modelling) methods have been suggested. Preliminary results suggested efficacy of these in-situ methods.
Development and Demonstration of a Cost-Effective In-Vehicle Lane Departure and Advanced Curve Speed Warning System
(Minnesota Department of Transportation, 2018-12) Faizan, Muhammad; Hussain, Shah; Hayee, M. I.
A Lane-Departure Warning System (LDWS) and Advance Curve -Warning System (ACWS) are critical among several Advanced Driver- Assistance Systems (ADAS) functions, having significant potential to reduce crashes. Generally, LDWS us e different image processing or optical s canning techniques to detect a lane departure. Such LDWS have some limitations such as harsh weather or irregular la ne markings can influence their performance. Other LDWS use a GPS receiver with access to digital maps with lane-level resolution to improve the system's efficiency but make the overall system more complex and expensive. In this report, a lane-departure detection method is proposed, which uses a standard GPS receiver to determine the lateral shift of a vehicle by comparing a vehicle’s trajectory to a reference road direction without the need of any digital maps with lane-level resolution. This method only needs road-level information from a standard digital mapping database. Furthermore, the system estimates the road curvature and provides advisory speed for a given curve simultaneously. The field test results show that the proposed system can detect a true lane departure with an accuracy of almost 100%. Although no true lane departure was left undetected, occasional false lane departures were detected about 10% of the time when the vehicle did not actually depart its lane. Furthermore, system always issues the curve warning with an advisory speed at a safe distance well ahead of time.
Development and Demonstration of Merge Assist System using Connected Vehicle Technology
(Center for Transportation Studies, University of Minnesota, 2019-04) Hussain, Shah; Peng, Zhiyuan; Hayee, M. Imran
One potential area to improve driver safety and traffic mobility is around merge points of two roadways, e.g., at a typical freeway entrance ramp. Due to poor visibility because of weather or complex road infrastructure, on many such entrance ramps, it may become difficult for the driver on the merging/entrance ramp to clearly see the vehicles travelling on the main freeway, making it difficult to merge. A fundamental requirement to facilitate many advance driver assistance systems (ADAS) functions including a merge assist system is to accurately acquire vehicle positioning information. Accurate position information can be obtained using either sensor-based systems (camera-based, radar, lidar) or global navigation satellite systems (GPS, DGPS, RTK). For these systems to work well for practical road and weather conditions, advanced techniques and algorithms are needed, which make the system complex and expensive to implement. In this research project, we propose a merge assist system by acquiring the relative positioning of vehicles using standard GPS receivers and dedicated short-range communication (DSRC) based vehicle-to-vehicle (V2V) communication. The DSRC-equipped vehicles travelling on the main freeway and on the entrance-ramp will periodically communicate their positioning information with each other. Using that information, the relative trajectories, relative lane, and position of all DSRC-equipped vehicles travelling on the main freeway will be calculated and recorded in real time in the vehicle travelling on the entrance ramp. Finally, a merge-time cushion will also be calculated, which could potentially be used to assist the driver of the ramp vehicle to safely merge into the freeway.
Development of a Sensor Platform for Roadway Mapping: Part B – Mapping the Road Fog Lines
(Minnesota Department of Transportation, 2015-04) Davis, Brian; Donath, Max
Our objective is the development and evaluation of a low-cost, vehicle-mounted sensor suite capable of generating map data with lane and road boundary information accurate to the 10 cm (4 in) level. Such a map could be used for a number of different applications including GNSS/GPS based lane departure avoidance systems, smart phone based dynamic curve speed warning systems, basemap improvements, among others. The sensor suite used consists of a high accuracy GNSS receiver, a side-facing video camera, and a computer. Including cabling and mounting hardware, the equipment costs were roughly $30,000. Here, the side-facing camera is used to record video of the ground adjacent to the passenger side of the vehicle. The video is processed using a computer vision algorithm that locates the fog line within the video frame. Using vehicle position data (provided by GNSS) and previously collected video calibration data, the fog line is located in real-world coordinates. The system was tested on two roads (primarily two-lane, undivided highway) for which high accuracy (<10 cm) maps were available. This offset between the reference data and the computed fog line position was generally better than 7.5 cm (3 in). The results of this work demonstrate that it is feasible to use a camera to detect the position of a road’s fog lines, or more broadly any other lane markings, which when integrated into a larger mobile data collection system, can provide accurate lane and road boundary information about road geometry.
Estimating Running Time and Demand for a Bus Rapid Transit Corridor
(University of Minnesota Center for Transportation Studies, 2009-12) Horning, Jessica; El-Geneidy, Ahmed M.; Hourdos, John
Due to the increasing ease and affordability of intelligent transportation systems (ITS) data collection, new methods for assessing conditions along current and future transit corridors are available. Measures such as average speed, travel time, and intersection delay can be determined for car and bus traffic along a corridor using readily available technology. These measures can be used to monitor the performance of the transportation system for existing modes and to estimate measures for proposed additions to the system. The goal of this research is to utilize GPS device records from regular vehicles as well as busses to estimate running time and potential passenger demand for a proposed Bus Rapid Transit (BRT) corridor on Cedar Avenue in the southern Twin Cities Metropolitan Area. Demand for future BRT service is predicted based on frequency and reliability of service and socio-demographic characteristics of the region around the corridor. Average passenger counts for existing transit service along the corridor in combination with existing commuting patterns in the region are used to estimate passenger demand. The running time and demand models produced by this study can be integrated with existing cost benefit software to evaluate the effects of intelligent transportation systems technologies on BRT running time (IBAT). The findings of this research introduce a benchmark for comparison between transit and private vehicle running time for general applications in Hennepin County. These findings also help to create additional understanding of the potential for BRT service in the Twin Cities region.
Evaluation of Low-Cost, Centimeter-Level Accuracy OEM GNSS Receivers
(Minnesota Department of Transportation, 2018-02) Jackson, John; Saborio, Ricardo; Ghazanfar, Syed Anas; Gebre-Egziabher, Demoz; Davis, Brian
This report discusses the results of a study to quantify the performance of low-cost, centimeter-level accurate Global Navigation Satellite Systems (GNSS) receivers that have appeared on the market in the last few years. Centimeter-level accuracy is achieved using a complex algorithm known as real-time kinematic (RTK) processing. It involves processing correction data from a ground network of GNSS receivers in addition to the signals transmitted by the GNSS satellites. This makes RTK-capable receivers costly (in excess of $10,000) and bulky, making them unsuitable for cost- and size-sensitive transportation applications (e.g., driver assist systems in vehicles). If inexpensive GNSS receivers capable of generating a position solution with centimeter accuracy were widely available, they would push the GNSS revolution in ground transportation even further as an enabler of safety enhancements such as ubiquitous lane-departure warning systems and enhanced stability-control systems. Recently manufacturers have been advertising the availability of low-cost (< $1,000) RTK-capable receivers. The work described in this report provides an independent performance assessment of these receivers relative to high-end (and costly) receivers in realistic settings encountered in transportation applications.
Feasibility of Using GPS to Track Bicycle Lane Positioning
(Intelligent Transportation Systems Institute, Center for Transportation Studies, University of Minnesota, 2013-03) Lindsey, Greg; Hankey, Steve; Wang, Xize; Chen, Junzhou; Gorjestani, Alec
Researchers have shown that GPS units in smartphones can be used to identify routes taken by cyclists, including whether cyclists deviate from shortest paths to use bike lanes and other facilities. Researchers previously have not reported whether GPS tracking can be used to monitor whether and how bicyclists actually use lanes on streets, where these lanes have been provided, or other types of facilities. The objective of this research was to determine whether smartphone GPS units or enhanced GPS units could be used to track and map the location of cyclists on streets. The research team modified an open-source smartphone application (CycleTracks) to integrate with a higher-quality external GPS unit. Cyclists then mounted the smartphone with route-tracking applications to bicycles and repeatedly rode four different routes. The routes for the field tests were chosen because each included a striped lane for bicycle traffic and because the routes bisected a variety of built urban environments, ranging from an open location on a bridge over the Mississippi River to a narrow urban street lined by tall, multi-story office buildings. The field tests demonstrated that neither the smartphone GPS units nor the higher-quality external GPS receiver generate data accurate enough to monitor bicyclists’ use of bike lanes or other facilities. This lack of accuracy means that researchers interested in obtaining data about the propensity of cyclists to ride in lanes, when available, must rely on other technologies to obtain data for analyses.
Home range overlap indices implemented using kernel density estimators with plug-in smoothing parameters and Program R
(2014-04-18) Fieberg, John R; jfieberg@umn.edu; Fieberg, John R
This collection contains R code to implement the home range overlap indices evaluated by Fieberg and Kochanny (2005). These indices have been incorporated into the adehabitat package of Program R. However, the adehabitat package does not currently (as of April 2014) allow calculation of home ranges using the 'plug-in' method for choosing smoothing parameters when estimating home ranges using kernel density estimates. In addition, the code here allows one to use two separate smoothing parameters rather than a single parameter (as in the current version of adehabitat). An illustrative example is included that makes use wild boar location data contained in the adehabitat package. For references, see README.txt.
An In-Vehicle Lane Departure and Erratic Driving Warning System using V2V Communication and Standard GPS Technology
(2021-06) Hossain, Md Touhid
Some of the critical features of Advanced Driver Assistance Systems (ADAS), including unintentional lane departure warning and erratic driving warning have significant potential to reduce crashes. Generally, these systems use either various image processing techniques or Global Positioning System (GPS) technology with lane-level resolution maps. However, these are expensive to implement as well as have some limitations, such as harsh weather or irregular lane markings can drastically reduce their performance. Previously, we developed a lane departure warning system (LDWS) where we generated road reference heading (RRH) form a vehicle’s past travel trajectories acquired by GPS to detect unintentional lane departure. But when a vehicle travels for the first time on a given road, it does not have any past trajectory of that road to generate RRH of that road needed to detect unintentional lane departure. So, in this thesis, we have improved our previously developed LDWS by adding a vehicle to vehicle (V2V) communication feature to the existing LDWS so that a vehicle traveling on a road for the first time can acquire the RRH of that road from a nearby vehicle via V2V communication. Furthermore, we have also enhanced the existing LDWS by adding a parallel erratic driving warning system (EWDS) to detect erratic driving behavior of a vehicle so that the system can issue timely warnings to alert the driver. We have considered two most common erratic driving scenarios; inter lane change and intra lane change erratic driving. We have developed an algorithm to detect both erratic driving behaviors and implemented the algorithm in a prototype system. We have extensively tested the V2V communication feature of LDWS as well as theEDWS in the field to evaluate their accuracy in real-time. Our field test results show an RRH successfully transfers from one vehicle to another, and the EDWS can detect each erratic driving scenario during the test drives accurately in a timely manner.
Inexpensive 2D Optical Sensor for GPS Augmentation
(Intelligent Transportation Systems Institute, Center for Transportation Studies, University of Minnesota, 2012-12) Cheng, Pi-Ming; Shankwitz, Craig; Arpin, Eddie
Differential Global Positioning Systems (DGPS) are susceptible to outages due to blocked or missing satellite signals and/or blocked or missing DGPS correction messages. Outages arise primarily due to environmental reasons: passing under bridges, passing under overhead highway signs, adjacent foliage, etc. Generally, these outages are spatially deterministic, and can be accurately predicted. These outages distract drivers using DGPS-based driver assistive systems, and limit the system robustness. Inertial measurements have been proposed as an augmentation for DGPS. Tests have shown that error rates for even emerging technologies are still too high; a vehicle can maintain lane position for less than three to four seconds. Ring laser gyros can do the job, but $100K per axis is still too expensive for road-going vehicles. To provide robust vehicle positioning in the face of DGPS outages, the IV Lab has developed a technique by which a non-contact, 2D true ground velocity sensor is used to guide the vehicle. Although far from fully developed, the system can maintain vehicle position within a lane for GPS outages of up to 20 seconds. New dual frequency, carrier phase DGPS systems generally require less than 20 seconds to acquire a "fix" solution after a GPS outage, so the performance of this system should be adequate for augmentation. Proposed herein is basic research which may lead to the development of an inexpensive, 2D, non-contact velocity sensor optimized for vehicle guidance during periods of DGPS outages.
Safetruck: Sensing and Control to Enhance Vehicle Safety
(Minnesota Department of Transportation, 1997-12) Alexander, Lee; Bajikar, Sundeep; Lim, Heon-Min; Morellas, Vassilios; Morris, Ted; Donath, Max
This report summarizes the work performed during the 18-month period ending in December 1997. Researchers investigated the use of differential global positioning systems (GPS), inertial measurement, and other sensing technologies as the basis of a system that would prevent crashes. Such a system attempts to control the vehicle if it leaves the lane because the driver is incapacitated. The report includes in its appendices related work on driver fatigue and a bibliography on the effect of drugs and alcohol on driving behavior. The long-term goal of this research involves development of a "driver-centered" vehicle control system capable of providing lane-keeping feedback to the driver, and, ifnecessary, of imposing aggressive intervention strategies to take over control of the vehicle, steer it to a safe position on the shoulder, and stop it. This research also targets the development of "driver assistive" technologies--such as Heads Up Display and torque feedback supplied by the steering wheel--which provide information to the driver without necessarily requiring computer control of the vehicle. The highlight achievement during this funding period has been the successful demonstration of a GPS-based automated lane-keeping mode of a tractor-trailer on the Minnesota Road Research Project (Mn/ROAD) test track. The report concludes with a strategy for pursuing future deployment.
Traffic Flow and Road User Impacts of the Collapse of the I- 35W Bridge over the Mississippi River
(Minnesota Department of Transportation, Research Services Section, 2010-07) Zhu, Shanjiang; Levinson, David; Liu, Henry; Harder, Kathleen; Dancyzk, Adam
Major network disruptions have significant impacts on local travelers. A good understanding of behavioral reactions to such incidents is crucial for traffic mitigation, management, and planning. Existing research on such topics is limited. The collapse of the I-35W Mississippi River Bridge (August 1, 2007) abruptly disrupted habitual routes of about 14,000 daily trips and forced even more travelers to adapt their travel pattern to evolving network conditions. The opening of the replacement bridge on November 18, 2008 generated another disturbance (this time predictable) on the network. Such “natural” experiments provide unique opportunities for behavioral studies. This study focuses on the traffic and behavioral reactions to both bridge collapse and bridge reopening and contributes to general knowledge by identifying unique patterns following different events. Three types of data collection efforts have been conducted during the appropriate frame of reference (i.e. before vs. after bridge reconstruction): 1) GPS tracking data and associated user surveys, 2) paper and internet-based survey data gauging travel behavior in the post-bridge reconstruction phase, and 3) aggregate data relating to freeway and arterial traffic flows, traffic control, and transit ridership. Differences in reactions to planned versus unplanned events were revealed. Changes in travel cost were evaluated and their temporal and spatial patterns were analyzed. This report concludes with thorough discussions of findings from this study and policy implications.
Using Archived Truck GPS Data for Freight Performance Analysis on I-94/I-90 from the Twin Cities to Chicago
(University of Minnesota Center for Transportation Studies, 2009-11) Liao, Chen-Fu
Interstate 94 is a key freight corridor for goods transportation between Minneapolis and Chicago. This project proposes to utilize the FPM data and information from ATRI to study the I-94/I-90 freight corridor. Freight performance will be evaluated and analyzed to compare truck travel time with respect to duration, reliability, and seasonal variation. This data analysis process can be used for freight transportation planning and decision-making and potentially will be scalable for nationwide deployment and implementation on the country’s significant freight corridors.
Using Truck GPS Data for Freight Performance Analysis in the Twin Cities Metro Area
(Minnesota Department of Transportation Research Services & Library, 2014-03) Chen-Fu, Liao
Building on our previous efforts to study freight mobility and reliability, a GPS-based data analysis methodology was developed to study the freight performance of heavy commercial trucks along 38 key freight corridors in the Twin Cities metropolitan area (TCMA). One year of truck GPS data collected in 2012 was obtained from American Transportation Research Institute (ATRI) to study freight mobility and reliability. Several performance measures, such as truck mobility, delay, and reliability index, were computed and analyzed by route, roadway segment, and time of day. For data quality and reliability verification, average truck speed and hourly volume percentage computed from the truck GPS data were validated with weigh-in-motion (WIM) and automatic traffic recorders (ATR) data at selected locations. The GPS based freight analysis methodology offers potential opportunities for freight planners and managers to generate reliable measures in a timely manner. The resulting performance measures indicate that these measures derived from truck GPS data can be used to support the USDOT performance measure initiative and support regional surface freight planner in identifying freight bottlenecks, infrastructure improvement needs, and operational strategies to promote efficient freight movement. FHWA recently announced the National Performance Measurement Research Data Set (NPMRDS) to support its Freight Performance Measurement (FPM). The NPMRDS includes probe vehicle based travel time data in every 5-minute interval. This report also explored the feasibility of using one month of NPMRDS data in Minnesota to compute freight mobility and speed variations along the National Highway System (NHS) during AM and PM peak periods.

University Digital Conservancy

Browse by Subject

Browsing by Subject "Global Positioning System"