Method for Improving Indoor Positioning Accuracy Using Extended Kalman Filter
Table 1
Four proximity states of iBeacon.
Glossary
Description
Accuracy
A distance value in terms of meters
Proximity state (estimates of the distance between the iBeacon transmitter and the smartphone that appears in the CLBeacon class)
(i) Immediate: distance between 0 and 1 m; high reliability. (ii) Near: distance between 1 and 3 m; trusted distance. (iii) Far: distance greater than 3 m. The measured distance is not the actual distance to the iBeacon transmitter. (iv) Unknown: iBeacon signal is not received. Measurement reference value: the RSSI values (−59 dBm) received at a distance of 1 m.