In unilateral systems tag’s localization is calculated based on the signals transmitted by system infrastructure (anchors). Therefore tag location can be derived directly in the tag device. Such approach allows to construct easily scalable systems and is a good choice when developing navigation systems. Architecture of a unilateral UWB positioning system is presented in Fig.1.
Fig 1 Positioning system architecture (developed within the EIGER project)
The tag acts as a receiver and measures TDOAs from anchors transmissions and calculates its position. The result can be transferred to other devices over wireless or wired link. Wirelessly synchronized anchors successively transmit packets containing data required for position calculation (e.g. anchor identifiers and coordinates). The described architecture was used in the positioning system developed within the EIGER project.
The unilateral system developed by UWB Systems Group utilizes devices based on DW1000 ultrawideband transceiver chip. The block diagram of the device used as an anchor and the receiver in the UWB positioning system demonstrator is shown in Fig. 2.
Fig.2 Block diagram of the developed module
The tag/anchor module consists of: DW1000 UWB chip, TCXO and microcontroller. The device includes also WiFi and Bluetooh modules, which can be used to communicate with other system parts (e.g. smartphone, PC). The assembled board with attached UWB monopole antenna is presented in Fig. 3
Fig. 3 The assembled board