1. BikeLoc: a Real-time High-Precision Bicycle Localization
System Using Synthetic Aperture Radar
Hongjiang Lyu, Linghe Kong, Chengzhang Li
Yunxin Liu, Jiansong Zhang, Guihai Chen
APNet 2017

2. Development of Smart Bicycles

3. Why not GPS?
GPS's error is at meters level.
It performs poorly under tall
buildings and in the tunnel.

4. 1 2 3 Requirements for Bicycle Localization System Portablility
Little power consumption 2
Online algorithm 3

5. A new bicycle localization system
Related works:
S. Kumar, S. Gil, D. Katabi, and D. Rus. Accurate indoor localization
with zero start-up cost. MobiCom, 2014.
J. Xiong and K. Jamieson. Arraytrack: A fine-grained indoor location
system. NSDI, 2013.
S. Nirjon, J. Liu, G. DeJean, B. Priyantha, Y. Jin, and T. Hart.
Coin-gps: indoor localization from direct gps receiving. MobiSys, 2014.
BikeLoc:

6. Overview of BikeLoc 1 2 Take Channel State Information (CSI) snapshots
Performing Circular
Synthetic Aperture Radar 2
Determine the
direction of APs 3

7. Theoretical Part Circular Synthetic Aperture Radar Wireless Channels
Relative Power
Relative Power

8. Theoretical Part Obstacle Circular Synthetic Aperture Radar
Wireless Channels
Relative Power
Relative Power

9. Theoretical Part
Extending to Three Dimensions
Relative Power

10. Design of BikeLoc Position of the APs Direction of APsz
Position of
the APs x y
Direction of APs
Motion Sensor Localization
Height of
the wheel
Real-time
Localization
Position of
the wheel
Starting
point
Middle
point
Current
point

11. Design of BikeLoc

12. Why Wheel? We use Circular Synthetic Aperture Radar (CSAR).
CSAR is tansition-resilient.

13. Hardware Prototype of BikeLoc
Laptop
Mobike
Antennas
Gyroscope

14. Relative power among different
Experimental Results
Relative power among different
azimuthal and polar angle with antenna pairs:
A1A2, A1A3, A2A3 and Sum of them. A2 A1 A3
Accuracy: 1.5°
A1A2
Sum
A2A3
A1A3

15. Angle-Of-Arrival Estimation Accuracy
AOA Estimation of Different Antenna Pairs:

16. Localization Accuracy
Localization Accuracy Against Number of APs:

17. Localization Accuracy
Error in Distance of Motion Sensor Localization：

18. Conclusion
We design BikeLoc, a novel design to enable accurate bicycle localization based on a subtle combination of the wheel and WiFi devices.
We implement a prototype of BikeLoc. In our testbed, we showed that BikeLoc is very promising to achieve tens of centimeters level localization accuracy.

19. Q&A 19