EnTracked: Energy-Efficient Robust Position Tracking for

Mobile DevicesMikkel Baun Kjærgaard, Jakob Langdal, Torben Godsk, Thomas Toftkjær

MobiSys2009

MotivationA system that,

The estimation and prediction of system conditions and mobility

Schedules position updates to both minimize energy consumption and optimize robustness.

Platform: Nokia N95,AccelerometerGPSRadio (3G)

Power ModelInstantaneous model is not accurate,

Example, TOSSIM.

Concerning delay impact,Request delayPower-off delay

Power ModelRequest delay

GPS

Radio

Power ModelPower-off delay

EnTrackedPosition-base application

EnTrackedEnTracked client flow

Detecting Movement Using accelerometer

Estimating SpeedUsing GPS

Error Model

ExperienceEmulation

ExperienceEmulation

ExperienceReal-world validation

ExperienceReal-world validation