ECE 480 Design Team 6ECE 480 Design Team 6Lightweight Speed and Lightweight Speed and

Distance Sensor for Skiers Distance Sensor for Skiers and Snowboardersand Snowboarders

Michael Bekkala

Michael Blair

Michael Carpenter

Matthew Guibord

Abhinav Parvataneni

Facilitator: Dr. Shanker Balasubramaniam

AgendaAgenda

BackgroundBackground ObjectiveObjective Design SpecificationsDesign Specifications Potential SolutionsPotential Solutions Proposed SolutionProposed Solution Conceptual flowchart and HardwareConceptual flowchart and Hardware

Goal of Competitive SportsGoal of Competitive Sports

1)1) WinWin

2)2) Perform better than the competitionPerform better than the competition

3)3) Improve performanceImprove performance• Requires tracking of statisticsRequires tracking of statistics

Jump HigherJump Higher Run FasterRun Faster Hit HarderHit Harder

Bicycle SpeedometerBicycle Speedometer

Sensor mounts to wheel and frameSensor mounts to wheel and frame Counts time between Counts time between

wheel sensor passing wheel sensor passing

frame sensorframe sensor Calculates wheel speedCalculates wheel speed Forward speed is Forward speed is

proportional to rotation of wheelproportional to rotation of wheel

Nike Plus (Nike+)Nike Plus (Nike+)

Sensor placed in shoeSensor placed in shoe Determines how long pressure is Determines how long pressure is

applied to the footapplied to the foot The time that pressure isThe time that pressure is

applied is directly applied is directly

proportional to the proportional to the

runner’s speedrunner’s speed

ObjectiveObjective Design a speed and distance sensor for skiing and Design a speed and distance sensor for skiing and

snowboardingsnowboarding

Current Products:Current Products:• ExpensiveExpensive• InaccurateInaccurate• InconvenientInconvenient

Objective:Objective:• Greater accuracyGreater accuracy• Lower costLower cost• Improve functionalityImprove functionality

Design SpecificationsDesign Specifications SafetySafety

• Disable display while movingDisable display while moving FunctionalityFunctionality

• User definable auto shutdown timeUser definable auto shutdown time• PC interface for data reviewPC interface for data review• Ease of use in winter apparel Ease of use in winter apparel

PackagingPackaging• Operate at subzero temperature (-10°F)Operate at subzero temperature (-10°F)• Shock resistantShock resistant• WaterproofWaterproof• Weigh less than 2 lbsWeigh less than 2 lbs

Cost - less than $500Cost - less than $500

Potential SolutionsPotential Solutions

1)1) Relative PositioningRelative Positioning

2)2) Inertial Navigation System (INS)Inertial Navigation System (INS)

3)3) Global Positioning System (GPS)Global Positioning System (GPS)

4)4) Integration of INS and GPSIntegration of INS and GPS

1. Relative Positioning1. Relative Positioning

Transmitter locally placedTransmitter locally placed• Sends out signal to receiverSends out signal to receiver• More transmitters = Better accuracyMore transmitters = Better accuracy

Receiver gets signal fromReceiver gets signal from

transmittertransmitter• Calculates distance from Calculates distance from

transmittertransmitter• Derivative of distance = SpeedDerivative of distance = Speed

1. Relative Positioning1. Relative Positioning

Advantages:Advantages:• AccurateAccurate• ReliableReliable• Independent of external systemsIndependent of external systems

Disadvantages:Disadvantages:• ComplexComplex• Requires a locally placed transmitterRequires a locally placed transmitter• Relative position vs. absolute positionRelative position vs. absolute position

2. Inertial Navigation System2. Inertial Navigation System 3 Accelerometers3 Accelerometers

• Measure Linear AccelerationMeasure Linear Acceleration• X, Y, Z Directions X, Y, Z Directions • Integrate to get speed and distanceIntegrate to get speed and distance

3 Gyroscopes3 Gyroscopes• Measure Angular VelocityMeasure Angular Velocity• Pitch, Roll, YawPitch, Roll, Yaw• Integrate to get angularIntegrate to get angular

positionposition Coordinate conversionCoordinate conversion

• Body Frame to ECEFBody Frame to ECEF

2. Inertial Navigation System2. Inertial Navigation System

Advantages:Advantages:• Very accurate for short periods of timeVery accurate for short periods of time• Updates faster than GPSUpdates faster than GPS

Disadvantages:Disadvantages:• Requires at least 6 sensorsRequires at least 6 sensors• Susceptible to bias driftsSusceptible to bias drifts• Error increases over time (t^2)Error increases over time (t^2)• Requires initial conditionRequires initial condition

3. Global Positioning System3. Global Positioning System Receives time data from satellitesReceives time data from satellites

• Requires very accurate timingRequires very accurate timing• Atomic clocks on board satellitesAtomic clocks on board satellites

Triangulates positionTriangulates position• Uses distance fromUses distance from

satellitessatellites• Fourth satelliteFourth satellite

used for error used for error correctioncorrection

3. Global Positioning System3. Global Positioning System

Advantages:Advantages:• InexpensiveInexpensive• Low PowerLow Power• Gives absolute positionGives absolute position• Reliable over long periods Reliable over long periods

of timeof time Disadvantages:Disadvantages:

• Low accuracy for moving targetsLow accuracy for moving targets

4. Integration of GPS and INS4. Integration of GPS and INS Proposed DesignProposed Design Combines both systems into oneCombines both systems into one Takes advantage of each systemTakes advantage of each system

• Short term accuracy of INSShort term accuracy of INS• Long term reliability of GPSLong term reliability of GPS

GPS keeps INS errors in checkGPS keeps INS errors in check Use Kalman filter to improve Use Kalman filter to improve

accuracy of integrated systemaccuracy of integrated system

4. Integration of INS and GPS4. Integration of INS and GPS Advantages:Advantages:

• Most accurateMost accurate• Takes advantage of each systemTakes advantage of each system• Gives absolute positionGives absolute position

Disadvantages:Disadvantages:• More complexMore complex• Requires heavy computationRequires heavy computation• Requires more hardwareRequires more hardware

Conceptual DesignConceptual Design

Hardware ComponentsHardware ComponentsArdupilot 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

Hardware ComponentsHardware ComponentsVenus GPS with SMA Connector

•Up to 10Hz refresh rate•28mA operating current•Accuracy is <2.5m

•Passive Antenna•-5dB Gain

Quadrifilar V Omnidirectional Passive GPS Antenna