Experimental Application of Global Positioning system To Locate Motor Vehicle Crashes: Impact on Time and Accuracy

1998 ◽  
Vol 1625 (1) ◽  
pp. 41-49 ◽  
Author(s):  
John S. Miller ◽  
Duane Karr
Keyword(s):  
Global Positioning System ◽  
Human Error ◽  
Motor Vehicle ◽  
Motor Vehicle Crash ◽  
Positioning System ◽  
Gps Receivers ◽  
Crash Data ◽  
Vehicle Crash ◽  
Global Positioning ◽  
Conventional Methods

Motor vehicle crash countermeasures often are selected after an extensive data analysis of the crash history of a roadway segment. The value of this analysis depends on the accuracy or precision with which the crash itself is located. yet this crash location only is as accurate as the estimate of the police officer. Global Positioning System (GPS) technology may have the potential to increase data accuracy and decrease the time spent to record crash locations. Over 10 months, 32 motor vehicle crash locations were determined by using both conventional methods and hand-held GPS receivers, and the timeliness and precision of the methods were compared. Local crash data analysts were asked how the improved precision affected their consideration of potential crash countermeasures with regard to five crashes selected from the sample. On average, measuring a crash location by using GPS receivers added up to 10 extra minutes, depending on the definition of the crash location, the technology employed, and how that technology was applied. The average difference between conventional methods of measuring the crash location and either GPS or a wheel ranged from 5 m (16 ft) to 39 m (130 ft), depending on how one defined the crash location. Although there are instances in which improved precision will affect the evaluation of crash countermeasures, survey respondents and the literature suggest that problems with conventional crash location methods often arise from human error, not a lack of precision inherent in the technology employed.

scholarly journals Global Positioning System (GPS) Accuracies in Eastern U.S. Deciduous and Conifer Forests

1996 ◽  
Vol 20 (2) ◽  
pp. 81-84 ◽  
Author(s):  
Christopher J. Deckert ◽  
Paul V. Bolstad
Keyword(s):  
Global Positioning System ◽  
Positioning System ◽  
Conifer Forests ◽  
Forest Canopies ◽  
Gps Receivers ◽  
Global Positioning ◽  
Corrected Data

Abstract This study determined horizontal positional errors when using C/A code GPS receivers under forest canopies and in varied terrain. Positional errors were evaluated for a total of 18 sites: three sites for each of six combinations of canopy (conifer, hardwood) and terrain (ridge, slope, valley). Ten replicates were collected at each site for each of 60, 200, and 500 position fixes. Differentially corrected positional accuracies from conifer sites averaged 18.4 ft, which was significantly greater than the 14.5 ft observed for hardwood sites. For differentially corrected data, positional errors generally increased from ridgetop to valley positions. - Errors decreased when the number of position fixes was increased. South. J. Appl. For. 20(2):81-84.

Evaluating the Ability of Global Positioning System Receivers to Measure a Real-World Operating Mode for Emissions Research

2005 ◽  
Vol 1941 (1) ◽  
pp. 43-50 ◽  
Author(s):  
Eric Jackson ◽  
Lisa Aultman-Hall ◽  
Britt A. Holmén ◽  
Jianhe Du
Keyword(s):  
Global Positioning System ◽  
Real World ◽  
Vehicle Emissions ◽  
Transportation Network ◽  
Operating Mode ◽  
Positioning System ◽  
Gps Receivers ◽  
The Real ◽  
Acceleration Data ◽  
Global Positioning

This paper evaluates the ability of Global Positioning System (GPS) receivers to determine accurately the second-by-second operating mode of a vehicle in the real-world transportation network. GPS offers the ability to obtain second-by-second velocity directly and to obtain acceleration data indirectly from a vehicle traveling in the real-world traffic network. Although GPS has been used successfully in travel behavior and route choice surveys, the uncertainty in accuracy of velocity and acceleration data obtained from the GPS warrants further investigation to gain a better understanding of the range and spatial distribution of vehicle emissions. In this study, data from two GPS receivers and a ScanTool were collected over five repetitions of a 65-mi route. The results indicate that GPS receivers perform as well as the ScanTool when measuring velocity. Furthermore, the GPS receivers determined the 1-s operating mode of the vehicle successfully when measured against the ScanTool. These results will aid in the future development of vehicle emissions models and allow for an analysis of real-world emissions based on real-world operating mode data.

scholarly journals Algorithms of Position and Velocity Estimation in GPS Receivers

2016 ◽  
Vol 23 (1) ◽  
pp. 53-68 ◽  
Author(s):  
Piotr Kaniewski ◽  
Rafał Gil ◽  
Stanisław Konatowski
Keyword(s):  
Global Positioning System ◽  
Velocity Estimation ◽  
Frame Of Reference ◽  
Positioning System ◽  
Gps Receivers ◽  
Extended Kalman Filters ◽  
Navigation Solution ◽  
Gps Satellites ◽  
Global Positioning ◽  
Simulation Results

Abstract Processing of signals in Global Positioning System (GPS) receivers includes numerous signal and data operations leading to calculation of coordinates and velocities of satellites in global Earth-Centered Earth-Fixed (ECEF) frame of reference as well as pseudoranges and delta-ranges between the user and all the tracked GPS satellites. Further processing of these data consists in estimation of the user’s position, velocity and time (PVT) and nowadays it is usually realized by means of an Extended Kalman Filters (EKF). The choice of measuring data processed by the Kalman filter significantly influences the accuracy of navigation solution. In simpler GPS receivers, the estimation of user’s position and velocity is based on pseudoranges only, whereas in more advanced ones delta-ranges are also applied. The paper describes both possible solutions and compares the accuracy of estimation of the user’s position and velocity in both cases. The comparison is based on simulation results, which are included in the paper.

scholarly journals Quantification of the Accuracy of Low Priced GPS Receivers for Crash Location

2010 ◽  
Author(s):  
Thobias Sando ◽  
Renatus Mussa ◽  
John Sobanjo ◽  
Lisa Spainhour
Keyword(s):  
Global Positioning System ◽  
Time Of Day ◽  
Gps Data ◽  
Positioning System ◽  
Gps Receiver ◽  
Accuracy Improvement ◽  
Gps Receivers ◽  
Location Data ◽  
Global Positioning ◽  
Potential Tool

Global positioning system (GPS) has been identified as a potential tool for capturing crash location data. This study quantifies factors that could affect the accuracy of GPS receivers. The results showed that GPS receiver orientation, site obstructions, and weather have significant effects on the accuracy of GPS receivers. Time of day and number of satellites were not found to significantly affect the accuracy of GPS receivers. HDOP values of 1.2 or less were found to be adequate for crash location purposes. An accuracy improvement of 20.7% was realized by filtering GPS data based on HDOP values.

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