The Cricket Location-Support System (2000)
Published in
- Proceeding
MobiCom ‘00 Proceedings of the 6th annual international conference on Mobile computing and networking
Online copies
Synopsis
Combination of RF and ultrasound to enable a listener to determine the distance to beacons.
Localization
Speed of signals
| Denote speed of | Approximate value in air (\(m/ms\)) | |
|---|---|---|
| \(v_s\) | ultrasound | 0.34 |
| \(v_r\) | RF | 299700 |
Distance measurement
Distance between beacon and listener \(d = \frac{v_rv_s\Delta t}{v_r - v_s} \approx v_s\Delta t\), where \(\Delta t\) is the time difference between the receipt of RF signal and ultrasonic signal.
Features
- Decentralized, and
- User privacy preserved, a listener is completely passive.
Comments