| Summary: | 碩士 === 長庚大學 === 資訊工程學系 === 104 === Design a low energy Bluetooth (BLE) device including reference-tag-based indoor position algorithm to solve different situations including location determining, route guideline and tracking in this study. It can not only help the visitor or patient to understand the position but also provide a system for medical staff to monitor the safety of patients and new born babies in hospital. This device is tiny enough to be embedded into visitor’s wristband, baby’s foot band and patient’s clothes. It is composed of signal control unit, signal sensing unit and wireless connection unit. The signal control unit is responsible to control and memorize the status of the device by an ultra-low power MCU and an EEPROM memory chip. The signal sensing unit is a motion tracking sensor module to capture the accelerometer signal. The wireless connection unit combined of beacon and Bluetooth module to send data package as a BLE sender. The indoor location-based services (LBS) system is combined with smart beacon and Wi-Fi gateway. Beacon plays the role of client and Wi-Fi gateway is server. The RSSI (Received Signal Strength Indicator) of BLE signal to determine whether the beacon owner is in a particular area.
In order to validate the performance and accuracy of the safety monitor system we proposed, we designed three experiments including (1) The Relevance of Distance and signal strength: we build the attenuation module of signal strength. We defined that BLE device sense distance is 10 meters. (2) The number of device and moving speed test: we found that it’s got higher lost rate if the number of device and moving speed is increased. But we reduce the lost rate by using two gateway, we got a great lost rate 4.61% when using two gateway is better than just a gateway is 14.61% by number and 18.46% by speed. (3) Positioning error rate: we got error rate is 5.19% by static threshold. Got error rate is 3.92% by half static threshold. Another method by dynamic threshold we got the best error rate is 3.77%.
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