ECE 480 Design Team 6

1. ECE 480 Design Team 6 Michael Bekkala Michael Blair Michael Carpenter Matthew Guibord Abhinav Parvataneni Facilitator: Dr. Shanker Balasubramaniam Lightweight Speed and Distance Sensor for Skiers and Snowboarders

2. Agenda • Background • Objective • Design Specifications • Potential Solutions • Proposed Solution • Conceptual flowchart and Hardware

3. Goal of Competitive Sports • Win • Perform better than the competition • Improve performance • Requires tracking of statistics • Jump Higher • Run Faster • Hit Harder

4. Bicycle Speedometer • Sensor mounts to wheel and frame • Counts time between wheel sensor passing frame sensor • Calculates wheel speed • Forward speed is proportional to rotation of wheel

5. Nike Plus (Nike+) • Sensor placed in shoe • Determines how long pressure is applied to the foot • The time that pressure is applied is directly proportional to the runner’s speed

6. Objective • Design a speed and distance sensor for skiing and snowboarding • Current Products: • Expensive • Inaccurate • Inconvenient • Objective: • Greater accuracy • Lower cost • Improve functionality

7. Design Specifications • Safety • Disable display while moving • Functionality • User definable auto shutdown time • PC interface for data review • Ease of use in winter apparel • Packaging • Operate at subzero temperature (-10°F) • Shock resistant • Waterproof • Weigh less than 2 lbs • Cost - less than $500

8. Potential Solutions • Relative Positioning • Inertial Navigation System (INS) • Global Positioning System (GPS) • Integration of INS and GPS

9. 1. Relative Positioning • Transmitter locally placed • Sends out signal to receiver • More transmitters = Better accuracy • Receiver gets signal from transmitter • Calculates distance from transmitter • Derivative of distance = Speed

10. 1. Relative Positioning • Advantages: • Accurate • Reliable • Independent of external systems • Disadvantages: • Complex • Requires a locally placed transmitter • Relative position vs. absolute position

11. 2. Inertial Navigation System • 3 Accelerometers • Measure Linear Acceleration • X, Y, Z Directions • Integrate to get speed and distance • 3 Gyroscopes • Measure Angular Velocity • Pitch, Roll, Yaw • Integrate to get angular position • Coordinate conversion • Body Frame to ECEF

12. 2. Inertial Navigation System • Advantages: • Very accurate for short periods of time • Updates faster than GPS • Disadvantages: • Requires at least 6 sensors • Susceptible to bias drifts • Error increases over time (t^2) • Requires initial condition

13. 3. Global Positioning System • Receives time data from satellites • Requires very accurate timing • Atomic clocks on board satellites • Triangulates position • Uses distance from satellites • Fourth satellite used for error correction

14. 3. Global Positioning System • Advantages: • Inexpensive • Low Power • Gives absolute position • Reliable over long periods of time • Disadvantages: • Low accuracy for moving targets

15. 4. Integration of GPS and INS • Proposed Design • Combines both systems into one • Takes advantage of each system • Short term accuracy of INS • Long term reliability of GPS • GPS keeps INS errors in check • Use Kalman filter to improve accuracy of integrated system

16. 4. Integration of INS and GPS • Advantages: • Most accurate • Takes advantage of each system • Gives absolute position • Disadvantages: • More complex • Requires heavy computation • Requires more hardware

17. Conceptual Design

18. Hardware Components Ardupilot Sensor Board - Six Degrees of Freedom • Three axis accelerometer (x,y,z) • One axis gyroscope (roll) Gyro Breakout Board - LPY5150AL Dual 1500°/s • Dual axis gyroscope • Senses pitch and yaw

19. Hardware Components Venus GPS with SMA Connector • Up to 10Hz refresh rate • 28mA operating current • Accuracy is <2.5m Quadrifilar V Omnidirectional Passive GPS Antenna • Passive Antenna • -5dB Gain