Abstract
High-accuracy indoor radio positioning can be achieved by using (ultra) wideband (UWB) radio signals. Multiple fixed anchor nodes are needed to compute the position or alternatively, specular multipath components (SMCs) extracted from radio signals can be exploited. In this work, we study a multipath-based, single-anchor positioning system that acquires directional measurements non-coherently. These non-coherent measurements can be obtained, e.g., from a single-chain mm-wave transceiver with analog beam steering or from a low-complexity ultra-wideband transceiver with switched directional antennas. The directional antennas support the separation of SMCs and the suppression of the undesired diffuse multipath component (DMC) with the benefit that the required signal bandwidth can be drastically reduced. The paper analyzes the Cramer-Rao lower bound (CRLB) on the position estimation error to gain insight in the influence of the system design parameters as well as the impact of the DMC on the position error. The CRLB is compared between the non-coherent antenna setup, a conventional array with coherent processing, and a single-antenna setup. A maximum-likelihood position estimation algorithm is formulated. Its performance is evaluated with synthetically generated data as well as with UWB measurements. We show that the accuracy and robustness are significantly improved due to the processing of angular information. Analyzing the measured data for a line-of-sight link, the median error decreases from 22 down to 7 cm, the measurements better than 20 cm increase from 46 to 95 %, and outliers above 50 cm reduce from 12 to 0%.
Highlights
IntroductionLarge bandwidth enables good time resolution, whereas multiple-input multiple-output (MIMO) processing enables good angle
We evaluate the position error bound (PEB) for specific scenarios in indoor environments
We consider up to second-order reflections, which means the number of considered specular multipath components (SMCs) is given by K ≤ Kseg(Kseg − 1) + 1
Summary
Large bandwidth enables good time resolution, whereas MIMO processing enables good angle. Resolution by exploiting array processing [8]–[14]. This conclusion has been drawn from the analysis of the Cramér-Rao lower bound (CRLB) on the position (and orientation) estimation error(s). The CRLB is a powerful tool to analyze the performance of positioning systems with regards to the impact of system parameters, such as bandwidth, carrier frequency, and antenna configuration. An increased signal bandwidth improves the delay resolution of SMCs and the capability to suppress the DMC [10], [12], [14], [15], and it improves the delay information that can be extracted from received radio signals.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
