A novel calibration method for RSS-based DoA estimation using ESPAR antennas

Low-Profile ESPAR Antenna for RSS-Based DoA Estimation in IoT Applications

“…8, with total root-meansquare (RMS) error equal to 0.85 • and 2 • precision being the maximum error value.In table 3 we have gathered obtained accuracy levels together with other relevant parameters of the proposed antenna together with the results already available in the literature. Comparing the obtained results with DoA estimation accuracy levels produced under the same SNR for high-profile ESPAR antenna having 12 unique main beam directions and the same energy-efficient simplified beam steering (0.61 • RMS error and 2 • precision reported in[31])…”

“…To verify DoA estimation performance of the proposed low-profile ESPAR antenna, recently introduced calibration method [31], which allows to determine the overall accuracy of RSS-based DoA estimation schemes employing ESPAR antennas, have been used. The method relies on softwaredefined radio (SDR) setup, presented in Fig.…”

ESPAR Antenna-Based WSN Node With DoA Estimation Capability

“…By changing steering vectors of the ESPAR antenna, it is possible to estimate the DoA of incoming RF signals by recording their RSS for each radiation pattern main beam direction [34], [35]. However, DoA estimation measurements for ESPAR antenna prototypes available in the literature were conducted in anechoic chambers using precise and advanced equipment and the PPCC algorithm results were calculated on a PC [33], [35], [36]. According to authors' best knowledge, such antenna has never been integrated with an inexpensive transceiver and microcontroller in order to develop a costeffective WSN node with beam steering and DoA estimation capabilities.…”

“…Although many different DoA techniques have been developed so far [30], those relying on low-cost reconfigurable antennas, which consume low energy for the switching process, and simple yet effective estimation algorithms are particularly interesting for WSN nodes. One of the most promising DoA estimation methods is power-pattern cross-correlation (PPCC) algorithm, originally introduced in [33], that provide accurate results and require acceptable number of simple operations [33], [36]. Therefore, it can successfully be implemented in a relatively simple microcontroller embedded within the NXP JN5168 chip chosen as the WSN node integrated transceiver.…”

“…It means that, by using 12 low-cost and low-current integrated SPDT FET switches, 12 directional radiation patterns are available and such an approach is free from the problem of availability of SPnT switches that would limit the total number of antennas used in [27]- [29]. This approach allows considerable reduction of energy consumption in an ESPAR antenna, so it can be integrated with battery-powered WSN nodes, and still accurately estimate DoA with 2 • precision using the PPCC algorithm in anechoic chamber measurements [36]. Therefore, by integrating such ESPAR antennas within WSN nodes employing simple and inexpensive transceivers that can measure RSS of incoming packets, one can develop WSN nodes capable of performing DoA estimation accurately and also set the required radiation direction, which can improve connectivity, coverage and energy efficiency of the whole network [4]- [6], [13], [14].…”