eComm 2011, San Francisco

Alternatives to GPS for Localization Leveraging

Smart Phones.

June 29th 2011 Slide 2 of 16

Location Applications

Monitoring

Tracking

Assisted Living

Targeted advertising

Social Networking

10% of all the iPhone applications employ location information

A quarter of all USA wireless phone users have utilized LBS

Slide 3 of 16

Satellite Navigation Systems

USA: GPS European Union: Galileo (2014)

– € 5.3 billion Russia: GLONNAS (2011)

– Most expensive project in Russian Federal Space Agency China: Compass (2020)

Other regional satellite-based systems:

France: Doris

India: IRNSS (2014)

Japan: QZSS (2013)

Slide 4 of 16

GPS Accuracy ~ 6 meters

GPS errors’ sources:

• Ionospheric effects (±5meters),

• Shifts in the satellite orbits (±2.5 meters),

• Satellite clock errors (±2 meters),

• Multipath effects (±1 meters),

• Tropospheric effects (±0.5 meters),

• Calculation and rounding errors (±1 meters)

Slide 5 of 16

Main Drawbacks of Satellite Systems

Power

Coverage

Slide 6 of 16

Satellite Navigation Systems

USA: GPS European Union: Galileo (2014)

– € 5.3 billion Russia: GLONNAS (2011)

– Most expensive project in Russian Federal Space Agency China: Compass (2020)

Other regional satellite-based systems:

France: Doris

India: IRNSS (2014)

Japan: QZSS (2013)

Slide 7 of 16

Alternatives to GPS

High Sensitivity GPS

• Advanced signal processing techniques.

- Low accuracy

Inertial Navigation Units (acc + gyro)

- Very expensive.

Radio Fingerprinting

Slide 8 of 16

WiFi Fingerprinting in the iPhone

Slide 9 of 40

Outdoor WiFi Fingerprinting in Smart Phones

Accuracy depends on density of Access Points

• Typical error: 50 meters.

Example: WiFi-based Localization by Google

Slide 10 of 16

Radio Fingerprinting

Slide 11 of 40

Cellular Fingerprinting

- Existing systems need Dedicated Hardware

- Smart Phones:

- Granularity is poor and Hardware dependent

- Slow refreshing rate

- Only RSSI information from the same SIM card operator

Slide 12 of 16

Fingerprinting with other Technologies

- Bluetooth

• Accuracy of up to 1.2 meters

- Dedicated Hardware

- Conventional Radio

- Dedicated Hardware

- Low accuracy (urban suburb)

- Digital TV

- Dedicated Hardware

- Zigbee

- Dedicated HardwareSlide 13 of 16

State-of-Art in WiFi Fingerprinting

- Radar, by Microsoft

• Accuracy 2 – 3 meters

- Dedicated Hardware

- Ekahau

• Accuracy 1 – 3 meters

- Dedicated Hardware

Slide 14 of 16

Improvements that Smart Phones can bring to Fingerprinting

Integrate both the online and offline phases in

fingerprinting

• Avoid errors due to differences in antenna characteristics and

measurement schemes between different equipments

• e.g. 10 dB between Dell Latitude laptop and Motorola Droid phone

Leverage accelerometer (gravity vector) and

magnetometer (orientation)

• Orientation of phone helps enhance the localization accuracy

Slide 15 of 16

WiFi Fingerprinting with Smart Phones

Slide 16 of 40

Stride Length Estimation with Wavelet

Slide 17 of 40