4/6/05                         GPS Technology                     For Use In Vehicle Accident Reconstruction              ...
4/6/05                   The Global Positioning System                               What is GPS?                  Global ...
4/6/05                              How GPS Works                  Satellites (Maintained by U.S. Government):            ...
4/6/05                     Psuedo-Random Code (PRC)                                      www.pieforensic.com              ...
4/6/05                                                          GPS Use                     Military/Civilian:            ...
4/6/05                              GPS In The News                  http://www.huffingtonpost.com/2011/02/21/anaheim-gps-...
4/6/05                                  GPS Accuracy                    Accuracy varies HIGHLY by GPS brand               ...
4/6/05                      Broadening the Horizons                  GPS data may shed light on:                    Which ...
4/6/05                  www.pieforensic.comwww.callpie.com                             9
4/6/05                       Viewing GPS Data Sets                  Viewable in software applications                    N...
4/6/05                  Vehicle Damages                      www.pieforensic.com                  Bicycle Damages         ...
4/6/05                                 Scene                                www.pieforensic.com                          B...
4/6/05                  Bicycle GPS Data                      www.pieforensic.com                  Bicycle GPS Data       ...
4/6/05                  Bicycle GPS Data                      www.pieforensic.com                  Bicycle GPS Data       ...
4/6/05                  Sample GPS Data Set: Use in AR                  Summary:                   GPS data depicts the mo...
4/6/05                   Location, location, location…                  Recall that your electronic device has the        ...
4/6/05                   Location, location, location…                        http://www.nytimes.com/2010/08/12/technology...
4/6/05                                 Solutions…                  Solution: User Beware                    Understand wha...
4/6/05                          The Lighter Slide                                            www.pieforensic.com          ...
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Using GPS to investigate Bike and Car Accidents

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Using GPS to investigate Bike and Car Accidents

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Using GPS to investigate Bike and Car Accidents

  1. 1. 4/6/05 GPS Technology For Use In Vehicle Accident Reconstruction Bradley J. Stolz, M.S., P.E., ACTAR Pie Forensic Consultants www.pieforensic.com © Copyright 2011 Pie Forensic Consultants, Inc. All rights reserved. Copyright Materials This presentation is protected by US and International copyright laws. Reproduction, distribution, display and use of the presentation without written permission of the speaker is prohibited. © 2011 Pie Forensic Consultants, Inc. All rights reserved. www.pieforensic.comwww.callpie.com 1
  2. 2. 4/6/05 The Global Positioning System What is GPS? Global Positioning System: a navigational system involving satellites and computers that can determine the latitude and longitude of a receiver on Earth by computing the time difference for signals from different satellites to reach the receiver. ~ Princeton WordNet 3.0 Layman’s Terms: GPS knows where you are (Lat, Long, Elev.), and how fast you’re going (Instant Speed). www.pieforensic.comwww.callpie.com 2
  3. 3. 4/6/05 How GPS Works Satellites (Maintained by U.S. Government): Orbiting constellation (31 in 2008), altitude of 12,550 miles Satellite emit identical signals Receivers (both Military and Civilian): Observes satellite signals, analyzing them Time Difference – Position Doppler Effect – Velocity Trilateration ~= Triangulation Minimum of 3 Signals necessary More “visible” signals = more accuracy www.pieforensic.com How GPS Works www.pieforensic.comwww.callpie.com 3
  4. 4. 4/6/05 Psuedo-Random Code (PRC) www.pieforensic.com Trilateration Similar to Triangulation, using distances in lieu of angles Minimum Satellites = 3 Assumed to be on surface of the Earth More Satellites result in better accuracy www.pieforensic.comwww.callpie.com 4
  5. 5. 4/6/05 GPS Use Military/Civilian: Navigation Missile, aircraft, land vehicle Vehicle-based, handheld units, cell phones Emergency FCC (2002) mandated in order for emergency services to locate 911 callers (tower-based) Location Geofencing: Kids, pets, phones, etc Geotagging: Photo location embedded Surveying (Waymarking) www.pieforensic.com GPS In The News http://www.abc15.com/dpp/entertainment/celebrity/Man-arrested-after-Lil-Wayne-video-shoot-theft_04082332www.callpie.com 5
  6. 6. 4/6/05 GPS In The News http://www.huffingtonpost.com/2011/02/21/anaheim-gps-truant-students_n_826100.html GPS Receiverswww.callpie.com 6
  7. 7. 4/6/05 GPS Accuracy Accuracy varies HIGHLY by GPS brand Proprietary calculations Typical Published values (GPS): Position: +/- 150 meters (492 feet) Velocity: +/- 2.5 meters/second (5.5 MPH) Typical Published values (DGPS): Differential GPS (assisted by ground-based reference stations) Position: +/- 3 meters (10 feet) Velocity: +/- 0.2 meters/second (0.5 MPH) Velocity data tends to be underestimated www.pieforensic.com Broadening the Horizons In the typical vehicle collision investigation, there are lots of unknowns: Which lane were they in? Where were they going? How fast were they driving? Who’s the “at-fault” driver? Etc, etc GPS data may be able to answer some of these questions www.pieforensic.comwww.callpie.com 7
  8. 8. 4/6/05 Broadening the Horizons GPS data may shed light on: Which lane were they in? Where were they going? Directions? How fast were they driving? Who’s the “at-fault” driver? GPS data can provide: Position (Lat, Long, Elev) Speed (mph, orientation) …at discrete times www.pieforensic.com Sample GPS Data Set NOT Collision-Related… Thankfully www.pieforensic.comwww.callpie.com 8
  9. 9. 4/6/05 www.pieforensic.comwww.callpie.com 9
  10. 10. 4/6/05 Viewing GPS Data Sets Viewable in software applications Numerous Web-based viewers Google Maps/Earth Sample GPS Data Set: Use in AR Vehicle/Bicycle Collision Front of vehicle collides with rear of bicycle Liability disputed Many issues, one of which was the pre- collision speed of the two vehicles www.pieforensic.comwww.callpie.com 10
  11. 11. 4/6/05 Vehicle Damages www.pieforensic.com Bicycle Damages www.pieforensic.comwww.callpie.com 11
  12. 12. 4/6/05 Scene www.pieforensic.com Bicycle GPS Data Cyclist wearing a Garmin device for logging/training purposes www.pieforensic.comwww.callpie.com 12
  13. 13. 4/6/05 Bicycle GPS Data www.pieforensic.com Bicycle GPS Data www.pieforensic.comwww.callpie.com 13
  14. 14. 4/6/05 Bicycle GPS Data www.pieforensic.com Bicycle GPS Data www.pieforensic.comwww.callpie.com 14
  15. 15. 4/6/05 Sample GPS Data Set: Use in AR Summary: GPS data depicts the motion history of the cyclist The GPS Data CANNOT place the cyclist in a specific lane of travel (or a portion of the lane) CAN depict the instantaneous speed of the Cyclist Critical piece of evidence in this case Side notes: “Extra” data also captured… Post-collision movement Cycling data XX-days after collision www.pieforensic.com Elephant in the Room: Current Topics www.pieforensic.comwww.callpie.com 15
  16. 16. 4/6/05 Location, location, location… Recall that your electronic device has the capability of identifying your location, with or without your knowledge. Photo-taking devices CAN embed the location of the photograph into the image data (Cameras, Cell Phones, etc) Is there a privacy issue? Most consumers do not know about “Geotagging” www.pieforensic.com Location, location, location… Recall that your electronic device has the capability of identifying your location, with or without your knowledge. Photo-taking devices CAN embed the location of the photograph into the image data (Cameras, Cell Phones, etc) Is there a privacy issue? Most consumers do not know about “Geotagging” www.pieforensic.comwww.callpie.com 16
  17. 17. 4/6/05 Location, location, location… http://www.nytimes.com/2010/08/12/technology/personaltech/12basics.html More Unknowns… Your (vehicle, phone, handheld device) may contain evidence related to an incident Difficult/Impossible to obtain if the user is unaware Example: Cyclist Collision Spoliation issues? While most consumers probably recognize the ability of their GPS device to navigate them through uncharted highways and byways, few realize that their device may play a serious role in the event of a crash www.pieforensic.comwww.callpie.com 17
  18. 18. 4/6/05 Solutions… Solution: User Beware Understand what the devices are doing Is it recording a path? How is the path downloaded? Most do not record paths under the factory settings Case Application: What data “the other side” might have Discovery language Re: EDR www.pieforensic.com Analogies The GPS is a silent witness, capable of providing an un-biased perspective on the events surrounding a collision. Analogous to an event data recorder (“black box”); Technology that has been widely utilized in collision reconstruction CRS 12-6-401 and 12-6-402 “ ’Event data’ means… vehicle speed, vehicle direction, vehicle location…” www.pieforensic.comwww.callpie.com 18
  19. 19. 4/6/05 The Lighter Slide www.pieforensic.com Thank You! Bradley J. Stolz, M.S., P.E., ACTAR Pie Forensic Consultants, Inc. Office: 303.552.0177 bstolz@pieforensic.com www.pieforensic.com © Copyright 2011 Pie Forensic Consultants, Inc. All rights reserved.www.callpie.com 19

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