Enhanced ranging using adaptive filter of ZIGBEE RSSI and LQI measurement

Adaptive Filtering for Indoor Localization using ZIGBEE RSSI and LQI Measurement

“…We used two different types of new filtering to smooth the real RSSI, 'LQI' filtering and 'BOTH' filtering, and compared the results. And we found that 'BOTH' filter smooth more the raw RSSI value than existing 'Fusion' filtering [27]. In our research we used an adaptive filter as it performs well to track an object under such changing conditions in the RF signal environment.…”

“…Reference nodes broadcast a message to inform their position at regular intervals. Unknown nodes receive the broadcast message from reference nodes and measure the strength of the received signal [4], [27], [28]. Localization errors for this method range from two to three meters at average, with indoor errors being larger than outdoor ones.…”

“…To determine the LQI threshold value, we use the defined LQI threshold value 105. For determining RSSI threshold value, we use ADD (average distance difference) value as a RSSI threshold average distance difference (ADD) [27]. At first we used LQI filtering technique to smooth the absolute RSSI values and after that we used BOTH filtering process.…”

“…The following equation has used to filter both RSSI and LQI values: From the above analyses, we can determine that BOTH filters perform better than the existing RSSI filter [4], Fusion filter [27] and our proposed LQI filter. …”

“…Moreover, the device calculates its own position based on its own measurements. The proposed protocol tries to improve the existing algorithms [4], [27] using RSSI and LQI values. The indoor localization systems presented in this report are based on the RSSI as a strength indicator and LQI as a quality indicator of received packets.…”