The iBeacon device was introduced by Apple in order to allow more precise location determination. This refers especially to indoor navigation where systems like GPS are not available. Originally developed for the iOS they are now also available for Android-based applications.

The iBeacons are based on the TI CC2540 or CC2541. They are hardware transmitters periodically (with approximately 1 to 10 Hz) broadcasting ("advertising") their identification and additional information that can be used to derive their location (sometimes called micro-location or indoor-geo-location). As with all wireless devices the RF signal's intensity is used to determine contectual information, like location or proximity to other BLE devices.

Using one iBeacon transmitter device simple proximity measurements are possible; using three or more beacons lateration methods can be applied to determine the location in two or three dimensions.

iBeacons are transmitting the following data (as advertising packets) for identification and location purposes:

• IDs: UUID (128 bit), Major (16 bit), Minor (16 bit)
  these values can be modified by the user (customer); they form a hierarchical addressing scheme to clearly identify their origin (e.g. company, shop, shelf, or similar)
• Transmission (Tx) power

When used for proximity purposes, three different ranges are generally distinguished:

• Immediate: less than 50 cm
• Near: approximately between 50 cm and 2/5 m
• Far: approximately between 2/5 m and 30/50 m
  

As with all RF application in which the so-called "Received Signal Strength Indicator (RSSI)" is used to measure distances (see for instance WLAN, ZigBee, etc.) the results are strongly affected by collateral effects (like attenuation, reflection) and are in general not very precise. The term "micro-location" is misleading, because as in all similar systems only an approximate location measurement is possible.

 

iBeacons (Hardware) currently available at Kiel University of Applied Sciences:

Currently the following devices are available. Please use the indicated links for additional technical information.

• April Brother BlueBeacon 101 based on TI CC2541 (manufactured by Beijing April Brother Technology Co., Ltd., China).
• April Brother AprilBeacon 202 based on TI CC2540 (manufactured by Beijing April Brother Technology Co., Ltd., China).
  
  These two devices are functionally similar devices with the difference that UUID, Major and Minor are fixed in the 101 model whereas these parameters can be customized in the 202 (OAD - over the air). Furthermore the 202 has a higher Tx power and consequently a higer range than the 101.

Links:

• Company Website
• iBeacon Wiki