With the SLS server monitor in the control room, you can check in real time who the worker is staying in the basement facility or how many workers there are.

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 Nordic 2.4 GHz-based, the WLAN Communication Reader
 Used for real-time management of racks in large computer labs.
 Location-based property management through regular ID transmission with active tags attached to the property.
 Adjust the transmission period using a 동작 sensor, and detect the elimination of abnormal tags using a switch

 Improve location accuracy with the nanotron CSS-based tag
 Enhance network reliability with the ZigBee-based reader
 Realize the ZigBee stack using the Radio Pulse mango.

Chirp Spread Spectrum(CSS) Modulation

For this CSS PHY using the 2.45 GHz band, unlike the existing IEEE 802.15.4., the DBO-CSK(Differential Bi-Orthogonal Chirp Shift Keying) modulation is adopted using the chirp pulse..
Using Nanotron’s TRX Transceiver Chip (NLSG0501A) featuring Multi-Dimensional Multipple Access (MDMA) which adopts the Chirp Spread Spectrum (CSS) modulation, we are producing tag modules and transceiver modules. Once finished, the hardware can realize the Symmetric Double-Sided Two-Way Ranging (SDS-TWR) method in firmware, an upgraded version of the Time-of-Flight (ToF) method. The system identifies the distance between the tag and the reader using the time-of-flight delay and, by expanding this time into a three-dimensional space, tracks the location of the tag using the delay time received from the readers in three or four different locations.

 Multi Dimensional Multiple Access (MDMA)
   Strength: Can obtain signals that are resistant to noise exposure.

Symmetric Double Sided Two Way Ranging (SDS-TWR) method using the time of flight of the radio propagation path
     Strength: No need for additional devices for time synchronization
     Can calibrate the accurancy of the crystal using the mean between tag and node.

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