An indoor variance-based localization technique utilizing the UWB estimation of geometrical propagation parameters

A novel localization framework is presented based on ultra-wideband (UWB) channel sounding, employing a triangulation method using the geometrical properties of propagation paths, such as time delay of arrival, angle of departure, angle of arrival, and their estimated variances. In order to extract these parameters from the UWB sounding data, an extension to the high-resolution RiMAX algorithm was developed, facilitating the analysis of these frequency-dependent multipath parameters. This framework was then tested by performing indoor measurements with a vector network analyzer and virtual antenna arrays. The estimated means and variances of these geometrical parameters were utilized to generate multiple sample sets of input values for our localization framework. Next to that, we consider the existence of multiple possible target locations, which were subsequently clustered using a Kim-Parks algorithm, resulting in a more robust estimation of each target node. Measurements reveal that our newly proposed technique achieves an average accuracy of 0.26, 0.28, and 0.90 m in line-of-sight (LoS), obstructed-LoS, and non-LoS scenarios, respectively, and this with only one single beacon node. Moreover, utilizing the estimated variances of the multipath parameters proved to enhance the location estimation significantly compared to only utilizing their estimated mean values

Indoor wireless communications and applications

Chapter 3 addresses challenges in radio link and system design in indoor scenarios. Given the fact that most human activities take place in indoor environments, the need for supporting ubiquitous indoor data connectivity and location/tracking service becomes even more important than in the previous decades. Specific technical challenges addressed in this section are(i), modelling complex indoor radio channels for effective antenna deployment, (ii), potential of millimeter-wave (mm-wave) radios for supporting higher data rates, and (iii), feasible indoor localisation and tracking techniques, which are summarised in three dedicated sections of this chapter

An indoor localization technique based on ultra-wideband AoD/AoA/ToA estimation

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Locating the information: applications, technologies and future aspects

In today’s world, the demand for information is growing rapidly with respect to the human curiosity to explore the inside and the outside of our planet. In a simple analogy, the human body has thousands of sensors called receptor neurons to obtain information such as temperature or pressure from the environment. Similarly, recent developments in electronics and wireless communications lead engineers to the design of small-sized, low-power, low-cost sensor nodes which have the ability to communicate with each other over short distances and collect the information that is gathered

Foldable all-textile cavity-backed slot antennas for personal UWB localization

An all-textile multimoded cavity-backed slot antenna has been designed and fabricated for body-worn impulse radio ultra-wideband (IR-UWB) operation in the 3,744-4,742.4 MHz frequency band, thereby covering Channels 2 and 3 of the IEEE 802.15.4a standard. Its light weight, mechanical flexibility, and small footprint of 35 mm x 56 mm facilitate integration into textile for radio communication equipment for first aid responders, personal locator beacons, and equipment for localization and medical monitoring of children or the elderly. The antenna features a stable radiation pattern and reflection coefficient in diverse operating conditions such as in free space, when subject to diverse bending radii and when deployed on the torso or upper right arm of a test person. The high isolation toward the wearer's body originates from the antenna's hemispherical radiation pattern with a -3 dB beamwidth of 120 degrees and a front-to-back ratio higher than 11 dB over the entire band. Moreover, the antenna exhibits a measured maximum gain higher than 6.3 dBi and a radiation efficiency over 75%. In addition, orientation-specific pulse distortion introduced by the antenna element is analyzed by means of the System Fidelity Factor (SFF). The SFF of the communication link between two instances of this antenna is higher than 94% for all directions within the antenna's -3 dB beamwidth. This easily wearable and deployable antenna is suitable to support IR-UWB localization with an accuracy in the order of 5 cm

Accuracy evaluation of probabilistic location methods in UWB-RFID systems

The present project is focused on investigating the achievable accuracy of classical location methods commonly used in wireless and proposing an alternative location method based on combining two of them. The first part of the project studies the advantages and disadvantages of extending Ultra Wideband and Radiofrequency Identification technologies on some classical location methods. As a result of the study and with the goal of improving accuracy in indoor radio propagation channels, the Received Strength Signal-based location method and the Time Difference Of Arrival-based location method are selected to be combined in the alternative location method, including the proper channel models. This combined location method takes advantage of the virtues of each location method and combines information in order to improve the estimation of one target's position when locating in indoor channel. The second part of the project is devoted to analyse and simulate the modified RSS, TDOA and Combined location methods, considering the randomness of a real multipath fading channel. Results show that the Combined location method performs always the best accuracy. Specifically in analytical study, the combined location method provides a deterministic error of 24 cm which represents an improvement of 54% and 15% of the RSS and TDOA accuracies respectively. In the simulated study, results show that it is able to improve the accuracy up to 46% and 85% of the RSS and TDOA respectively in specific evaluated points