scholarly journals The Forensic Engineering Use Of Precise Gps Measurements In Small Craft Casualty Cases

2006 ◽  
Vol 23 (1) ◽  
Author(s):  
John A. Cartner
Keyword(s):  
Global Positioning System ◽  
Rotational Behavior ◽  
Positioning System ◽  
Empirical Testing ◽  
Gps Measurements ◽  
Global Positioning ◽  
Small Craft ◽  
Forensic Engineering

Often In The Understanding Of The Events Leading To Casualties In Small Craft, It Is Useful To Know Both The Reconstructed Path Of The Centroid Of The Craft In The x-Y Plane As Well As Its Rotational Behavior Around The Z Axis. Precise Global Positioning System Measurements Can Provide Such Information. This Paper Describes The Use Of Such Measurements, And The Inferences Drawn From Them, In A Case Where The Craft Was Available For Empirical Testing Under Various Velocity Regimes While Planning And In Its Maximum-Turn Maneuvering Regime

Integration of the global positioning system with geodetic leveling surveys in ground subsidence studies

CISM journal ◽  
1989 ◽  
Vol 43 (4) ◽  
pp. 377-386 ◽  
Author(s):  
Adam Chrzanowski ◽  
Chen Yong-qi ◽  
Roger W. Leeman ◽  
Julio Leal ◽  
Maraven
Keyword(s):  
Global Positioning System ◽  
Vertical Component ◽  
Monitoring Network ◽  
Oil Fields ◽  
Ground Subsidence ◽  
Deformation Analysis ◽  
Positioning System ◽  
Gps Measurements ◽  
Global Positioning ◽  
Moderate Climate

Integration of GPS measurements with terrestrial geodetic leveling has been implemented by the authors in monitoring ground subsidence in oil fields in Venezuela in an area of about 50 km x 50 km. The subsidence rate reaches up to 20 cm/year. A mathematical model for combining the GPS surveys with dynamic leveling measurements has been developed by utilizing the well known University of New Brunswick generalized method of deformation analysis. The implementation of GPS was preceded by test surveys (5 survey campaigns) in Canada on a network with 0.7 km to 30 km baselines, using TI 4100, WM101, and Trimble 4000SX receivers, and on a portion of the monitoring network in Venezuela (2 survey campaigns) using WM101 receivers. The accuracy of the test surveys has been evaluated using MINQE technique and by comparing the subsidences determined with GPS and precise leveling. The results indicate that with C/A-code receivers and with the present geometry of the satellite distribution, the vertical component of the short and medium (up to 30 km) length of the GPS baselines can be determined with an accuracy ranging from 15 mm in a moderate climate to 30 mm in hot and humid conditions.

scholarly journals GPS Satellite Interference in Hungary

2001 ◽  
Vol 196 ◽  
pp. 319-323
Author(s):  
T. Borza ◽  
I. Fejes
Keyword(s):  
Radio Frequency ◽  
Global Positioning System ◽  
Digital Data ◽  
Signal Frequency ◽  
Control Network ◽  
Radio Frequency Interference ◽  
Positioning System ◽  
Gps Measurements ◽  
Global Positioning ◽  
Geodetic Control

Civil users of the NAVSTAR Global Positioning System (GPS) in Hungary occasionally experience interference at the 1575.42-MHz GPS signal frequency. As the application of the GPS technique spreads rapidly in our country, radio frequency interference (RFI) should be considered a serious threat. The new geodetic control network (OG-PSH) in Hungary is based on GPS measurements and incorporates more than 1100 sites. The paper reports the experiences gained during the establishment of the network. Interference sources were tracked to ground-based digital data transmissions for telecommunications, which operate mostly in the Western part of Hungary. Telecommunication regulations exceptionally allow such transmissions in specified countries. In order to warn potential GPS users, the interference sources are being mapped.

scholarly journals Forensic Engineering Investigation Of Intentional Mis-Calibration Of Vehicle Odometers

2009 ◽  
Vol 26 (1) ◽  
Author(s):  
Michael D. Leshner
Keyword(s):  
Global Positioning System ◽  
Fuel Economy ◽  
Economic Benefit ◽  
Motor Vehicles ◽  
Positioning System ◽  
Load Pressure ◽  
Global Positioning ◽  
Trip Distance ◽  
Forensic Engineering ◽  
Engineering Investigation

Odometers In Motor Vehicles Record And Display Distance Traveled. In Addition To Informing A Driver Of Trip Distance, This Measurement Is Used To Calculate Service Intervals, Lease Payments, Resale Value, Fuel Economy, And Warranty Limits. Distance Is Calculated From A Digital Accumulation Of Wheel Rotations And Knowledge Of The Tire Circumference. The Tire Circumference May Vary With Speed, Load, Pressure, Tread-Wear And Brand. This Investigation Compares Indicated Odometer Measurements With Simultaneous Measurements Using A Global Positioning System (Gps) Device On A Range Of Vehicle Models. While Some Models Have Odometer Systems With Reasonably Accurate Calibrations, Others Systematically Over-Register Odometer Distance. In The Opinion Of This Investigator, The Mis-Calibration Is Sometimes Intentional And Done For The Economic Benefit Of The Manufacturer.

Contemporary crustal movement of continental China obtained by global positioning system (GPS) measurements

2001 ◽  
Vol 46 (18) ◽  
pp. 1552-1554 ◽  
Author(s):  
Zongjin Ma ◽  
Xinlian Chen ◽  
Shuhua Ye ◽  
Xian Lai ◽  
Ziqing Wei ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Crustal Movement ◽  
Positioning System ◽  
Gps Measurements ◽  
Global Positioning

Soil salinity mapping with electromagnetic induction and satellite-based navigation methods

1994 ◽  
Vol 74 (3) ◽  
pp. 335-343 ◽  
Author(s):  
M. E. Cannon ◽  
G. Lachapelle ◽  
R. C. McKenzie
Keyword(s):  
Electrical Conductivity ◽  
Global Positioning System ◽  
Electromagnetic Induction ◽  
Field Measurements ◽  
Positioning System ◽  
Soil Electrical Conductivity ◽  
Post Processing ◽  
Differential Gps ◽  
Gps Measurements ◽  
Global Positioning

This project was undertaken to develop a system to map salinity with a towed electromagnetic induction meter (EM) and to position the meter with the Global Positioning System (GPS). The characteristics of the GPS are reviewed and the differential GPS (DGPS) mode of positioning, as applied to the EM meter positioning case, is explained. An EM38 salinity meter was time synchronized to GPS through a field portable personal computer (PC) and mounted on a non-magnetic toboggan for this purpose. The PC was also used to record all data for post-processing and analysis. The system was towed at velocities of up to 25 km h−1 during the field measurements. Continuous positioning of the system was achieved with an accuracy of 1–3 m. Salinity and GPS measurements were integrated and recorded on a field portable PC laptop. The results from a 30-ha site near Brooks are presented as well as those from a 100-ha site near Stettler, AB, which was surveyed in 3 h yielding 6000 salinity measurements. In order to test the repeatable accuracy of the system, the survey at Stettler was repeated the following day. The agreement is of the order of 1 dS m−1 which is satisfactory for most applications. The effect of measurement spacing on accuracy is also analysed using various scenarios. Key words: Soil electrical conductivity, salinity, satellite navigation, Global Positioning System, positioning, precision farming

scholarly journals Forensic Engineering Applications Of Gps Data

2012 ◽  
Vol 29 (1) ◽  
Author(s):  
Daniel J. Melcher
Keyword(s):  
Global Positioning System ◽  
Digital Data ◽  
Gps Data ◽  
Positioning System ◽  
Engineering Analysis ◽  
Analysis Framework ◽  
Data Types ◽  
Global Positioning ◽  
Forensic Engineering ◽  
Gps Devices

Digital Sources Of Data Have Become Increasingly Important In The Forensic Engineering Analysis Of Vehicular Collisions. One Such Type Of Data, From Global Positioning System (Gps) Devices, Has Increased In Prevalence Within The Last Decade. As With Other Digital Data Types, It Is Important For Forensic Engineers To Understand The Sources And Types Of Gps Data Before Applying Them Within Their Analysis Framework. Validation Of The Gps Concept And Individual Devices, And Examples Of Gps Accepted Use Within The Engineering Community, Make This Technology An Important And Appropriate Tool For Forensic Engineering Analysis. Gps Data Can Be Acquired From A Variety Of Electronic Data Recorder (Edr) Sources, Both On-Vehicle And Off-Vehicle. Many Gps Data Sources Have Limitations That Can Lead To Misapplications Or Incorrect Conclusions If Not Properly Studied. Appropriate Mathematical Calculations And Analytical Procedures Will Be Addressed, Including The Types Of Collision Events That Can Best Benefit From The Context Of Gps Data. Gps Data Applications In Real-World Forensic Engineering Cases, Including Insurance Claims And Litigation, Reflect The Power Of Robust Analysis And Well As The Potential For Erroneous Conclusions If The Data Are Misused By The Analyst.

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