Sensor Technologies for Determining Cyclist Power Output: A Comparison of Smartphone, Opposing Force and Strain Gauge Power Measurement Technologies Using Spatial Analysis by Doug Daniels A Thesis Presented to the Faculty of the USC Graduate School University of Southern California In Partial Fulfillment of the Requirements for the Degree Master of Science (Geographic Information Science and Technology) May 2017 Copyright ® 2017 by Doug Daniels ii Dedication I dedicate this thesis and journey through USC graduate school to my children Dylan and Walker Daniels. For all those times that dad was in his office with the door closed, working on projects, papers, data analysis and of course this thesis, I love you for helping dad make it through the long hours and seeing the light at the end of the tunnel. As you get older, I hope you take a moment to reflect on why your dad wanted to do this and understand that learning is a never-ending process, no matter how old you are! Set lofty goals for yourself, thinking bigger than what was previously known possible and always remember that hard work pays off. Love you always, Dad iii Table of Contents List of Figures .................................................................................................................................. vi List of Tables ................................................................................................................................... xi Acknowledgements ......................................................................................................................... xii List of Abbreviations .................................................................................................................... xiii Abstract .......................................................................................................................................... xiv Chapter 1: Introduction ..................................................................................................................... 1 1.1 Motivation ............................................................................................................................... 3 1.2 Project Overview ..................................................................................................................... 4 1.3 Thesis Organization ................................................................................................................. 6 Chapter 2: Background and Related Work ....................................................................................... 8 2.1 Power Measurements between Garmin Vector and SRM Cycle Power Meters ..................... 9 2.2 Power Measurements between PowerTap and SRM Cycle Power Meters ........................... 12 2.3 Power Measurements between Newton PowerPod and 3 different DFPM Cycle Power Meters .......................................................................................................................................... 14 2.4 Positional Accuracy of Assisted GPS Data (A-GPS) from High-Sensitivity GPS-enabled Mobile Phones ............................................................................................................................. 17 2.5 Data Acquisition using Smartphone Applications ................................................................ 20 Chapter 3: Research Design and Methods ...................................................................................... 26 3.1 Data Collection Equipment and Applications ....................................................................... 26 3.2 Specifications of Stages Cycling Power Meter (Model FSA 360) ........................................ 27 3.3 Specifications of PowerPod Power Meter ............................................................................. 28 3.4 Specifications of Innovative App Design (IAD) - Power Meter App ................................... 31 3.5 Data and Methods Objectives ............................................................................................... 32 3.6 Study Routes for Power Data Collection .............................................................................. 34 3.7 Data Collection Workflow .................................................................................................... 37 Chapter 4: Results ........................................................................................................................... 40 4.1 Study Route 1: Castle Pines North - Overview ..................................................................... 41 4.2 Comparison of Average Power Accuracies .......................................................................... 43 4.3 Comparison of Real Time Power Data Intervals within the Castle Pines North Route ........ 44 4.4 Comparison of GPS Road Network Accuracy ...................................................................... 48 4.5 Comparison of GPS Elevation Accuracy Agreement ........................................................... 50 4.6 Results Summary for Castle Pines North Route ................................................................... 52 4.7 Study Route 2: Deer Creek Canyon - Overview ................................................................... 53 4.8 Comparison of Average Power Accuracies .......................................................................... 54 4.9 Comparison of real time power data intervals within the Deer Creek Canyon route ........... 55 iv 4.10 Comparison of GPS Road Network Accuracy .................................................................... 59 4.11 Comparison of GPS Elevation Accuracy Agreement ......................................................... 61 4.12 Results Summary for Deer Creek Canyon route ................................................................. 64 4.13 Study Route 3: Lookout Mountain Road - Overview ........................................................ 65 4.14 Comparison of Power Averages Over Reference Power Meter .......................................... 67 4.15 Comparison of real time power data intervals within the Lookout Mountain Road route .. 67 4.16 Comparison of GPS Road Network Accuracy .................................................................... 72 4.17 Comparison of GPS Elevation Accuracy Agreement ......................................................... 73 4.18 Results Summary for Lookout Mountain Road route ......................................................... 76 Chapter 5: Cconclusions and Future Considerations ...................................................................... 77 5.1 Findings ................................................................................................................................. 77 5.2 Successes and Failures of Testing Methodology .................................................................. 79 5.3 Sources of Error .................................................................................................................... 80 5.4 SWOT Analysis ..................................................................................................................... 81 5.5 Future Considerations ........................................................................................................... 82 REFERENCES ............................................................................................................................... 84 v List of Figures Figure 1 Example power data line graph representing power outputs across 2 different power meters - StageONE and Competitor 1 - fatbirds.co.uk .................................2 Figure 1.1 Deer Creek Canyon ride representing different power outputs..............................3 Figure 1.2 Orbea Orca bike installed with Stage Cycling Power meter, Power Pod and IAD smartphone power application.................................................................4 Figure 1.3 Map overview of route study areas……………………………………………....5 Figure 1.4 Line graph comparing the power output of 2 power meters (Stages, PowerPod and IAD power app) over time………………………………6 Figure 1.5 Google Earth map showing power output in relation to location………………...6 Figure 2.1 Bicycle fitted with SRM cranks and Garmin Vector pedals that is attached to a Lemond Revolution indoor trainer……………………………..10 Figure 2.1.2 PPAs produced between the SRM and Garmin Vector systems………..….…..11 Figure 2.2 PowerTap and SRM Max Power Output (PO) during max test using 3 gear ratios…………………………………………………………….….13 Figure 2.3 Sprint section of the ride, using 30 second power smoothing. Power Pod (blue line) overestimate the output power by approximately 100 watts…………………………………………………………………….……15 Figure 2.3.1 Very tight agreement across all 4 power meters ....……………………………16 Figure 2.3.2 PowerPod compared to PowerTap P1 Pedal in Palma Majorca mountain ride…………………………………………………………………...16 Figure 2.4 Sample scatter plots of static outdoor accuracy tests……………………….……19 Figure 2.4.1 Sample of positional fixes during outdoor dynamic accuracy test…………….20 Figure 2.5 Backpack rig with smartphones and VBOX units mounted on frame…………...21 Figure 2.5.1 Imagery showing the study route path…………………………………………22 Figure 2.5.2 Bicycle with Runtastic applications compared to VBOX reference……………...………..................................................................................23 Figure 2.5.3 Comparing Apple iPhone 6 running Runtastic application to VBOX reference ……………………………………………………………..……….23 vi Figure 2.5.4 Close up image at 95 seconds of speed