Localization technique based on dual-frequency doppler ranging estimation

Abstract

Positioning awareness plays an important role in modern applications such as internet of thing (IoT) and intelligent transportation system (ITS). One of the commonly used positioning techniques is trilateration as it estimates the location of a blind device or node by using the distance from several other devices or anchor nodes. The ranging technique used to obtain distance information is a crucial step to provide high accuracy in location estimation. Dual-frequency Doppler radar (DFDR) ranging technique has been widely used in radars and radio frequency identification (RFID) applications. In radar application, this technique requires a closed-loop communication link to estimate distance and has not been exploited in single radio frequency transmission. In this thesis, a ranging technique not requiring a closedloop communication link named one-way forward communication link dual-frequency Doppler (DFD) ranging technique is introduced. The performances of the DFD distance estimation were analysed using simulations and experimental measurements. In the DFD experiment, the anchor node transmitted two different frequencies with a certain frequency separation. The blind node captured the received signal, and the phase difference was extracted and unwrapped using offline processing system. The phase difference between the two received signals was used for DFD ranging estimation before being applied to locate the position of the blind node through trilateration method. Software defined radio (SDR) platform using GNU radio and universal software radio peripheral (USRP) was used to develop the localization system. The experimental results showed that DFD ranging technique can deliver up to 84% distance estimation improvement in comparison to conventional receive signal strength (RSS) ranging technique. In conclusion, the proposed DFD ranging technique is a promising positioning solution for future applications such as IoT and ITS.