Innovative RF-Based Localization System for Multi-Person Tracking
"Explore a groundbreaking system enabling centimeter-scale RF localization of multiple individuals in indoor environments. Overcome challenges like multipath effects and mobile users with cutting-edge technology. Discover WiTrack advancements in body radio reflections and FMCW waves for precise tracking and localization."
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Presentation Transcript
1 Multi-Person Localization via RF Body Reflections NSDI 2015
2 Motivation device-based -> device-free
3 Challenges multipath effect the indoor multipath varies significantly when it is measured from different vantage points near-far problem Successive Silhouette Cancellation (SSC) which is inspired by successive interference cancellation localizing static users users still move slightly due to their breathing
4 Contributions This paper demonstrates the first device-free RF-localization system that can accurately localize multiple people to centimeter-scale in indoor multipath-rich environments. Motion Tracking 12.1cm in the x/y dimensions Localizing Static People 11.2 cm in the x/y dimensions Tracking Hand Movements a median accuracy of 10.3
5 WiTrack 3D Tracking via Body Radio Reflections single-person motion tracking via RF body reflections: 1) obtaining time-of-flight (TOF) measurements to various reflectors in the environment 2) eliminating TOF measurements due to reflections of static objects like walls and furniture 3)mapping the user s TOFs to a location NSDI 2014
6 WiTrack Frequency-Modulated Carrier Waves (FMCW)
7 WiTrack
8 WiTrack
9 WiTrack2.0 five transmit antennas and five receive antennas (1) Multi-shift FMCW (2)Successive Silhouette Cancellation (SSC)
10 Addressing Multi-path in Multi-User Localization The exact number would depend on multipath and noise in the environment as well as on the number of users we wish to localize
11 The Design of Multi-shift FMCW 1. one FMCW transmitter and a large number of receivers 2. multiple FMCW transmit and receive antennas different FMCW transmitters will interfere with each other Rx Tx2 Tx1
12 The Design of Multi-shift FMCW
13 Successive Silhouette Cancellation 1. SSC Detection: finds the location of the strongest user by overlaying the heatmaps of all Tx-Rx pairs. 2. SSC Re-mapping: maps a person s location to the set of TOFs that would have generated that location at each transmit-receive pair. 3. SSC Cancellation: cancels the impact of the person on the TOF profiles of all Tx-Rx pairs. 4. Iteration: re-computes the heatmaps using the TOF profiles after cancellation, overlays them, and proceeds to find the next strongest reflector.
14 Successive Silhouette Cancellation
15 Successive Silhouette Cancellation
16 Successive Silhouette Cancellation Refocusing Step Leveraging Motion Continuity Disentangling Crossing Paths Extending SSC to 3D Gesture Recognition
17 Localization Based On Breathing using a subtraction window of 2.5 seconds
18 Localization Based On Breathing
19 Evaluation
20 Limitation Number of Users Coverage Area Lack of Identification Limited Gesture Interface
21 Thanks!
