Bluetooth Low Energy
BLE RSSI for Proximity: Accuracy and Limitations
RSSI is a received signal indicator, not a direct distance measurement.
RSSI is a received signal indicator, not a direct distance measurement. Use it cautiously for proximity categories in changing environments.
Identify environmental variation
Bodies, metal, antenna orientation and reflections can change RSSI without a matching change in distance. Test the actual asset and receiver placement. A calibration taken in an empty room may not hold on a busy factory floor.
Use practical decision rules
Define near, uncertain and away states where the application allows them. Use suitable averaging and hysteresis to avoid rapid state changes, while checking the resulting delay. Keep signal absence separate from proof that an asset has physically left the area.
Validate against known positions
Collect readings across locations, orientations and normal activity. Report false detections as well as missed detections. If the business requires precise positioning or safety-related separation, assess a technology and validation method suited to that requirement.
FAQ
Can RSSI reliably give exact metres?
Not generally across uncontrolled environments; treat distance estimates as model-dependent and validate them.
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