Project Presentation: SpinLoc
Ted
2008/6/20
A quick review
• SpinLoc: a indoor localization system
• Utilize spinning beacons and Doppler
frequency shift to localize stationary target
• Experimental result:
– median error of 40~50 cm
– 90% error of 70~90 centimeters.
video demo
Improvement
• To target moving and stationary object
simultaneously
Proposed Solution: SpinTrack
• Integrate two system
– SpinLoc (for stationary targets)
– dTrack (for moving targets)
dTrack: Tracking mobile nodes using RF Doppler shifts, SenSys ’07
SpinTrack
• Basic idea: reverse the sender-receiver
deployment in SpinLoc plus some
stationary infrastructure nodes
• Advantage
– Can switch the SpinLoc and dTrack without
extra overhead
SpinTrack
Another improvement
• Scalability
• Note that SpinTrack can only target one
object per round
Proposed Solution: Scheduling
• Basic idea: to form the infrastructure
nodes into subgroups
• Each subgroup target one unique object
G1
G2
G1
G1: group 1
G2: group 2
O1
O2
O1: object 1
O2: object 2
G2
G1
G2
A possible solution
• Slotted time division schemes
scheduler
Object x
Object y
Object x
time
Object z
Etc…
Requirement
• Centralized control
• Global schedules
• Fine-grain time synchronization
Another advantage from scheduling
• Energy-efficiency
• Simply make the node into idle mode
when not functioning