In this paper, we propose a geometric positioning technique for cooperative localization in Wireless Networks. The proposed technique is based on building geometric constraints from radio observables. These constraints are then merged to estimate the true position. In this paper we address situations where blind nodes, due to the lack of radio observables, cooperate to estimate their positions. Compared to other techniques, Monte Carlo simulations illustrate interesting performances in terms of positioning accuracy and computation complexity and runtime.

In the specific context of wearable wireless networks, this work aims at improving the accuracy and the robustness of radiolocation solutions based on standard narrow-band radio technologies for user-centric mobile applications. The proposed solution takes benefits from off-body or body-to-body radio links, with respect to fixed elements of infrastructure or to other mobile equipped subjects, respectively. The main idea is to infer relative angular information between the carrying body's heading and the median direction of arrival of received signals. For this sake, we rely on differential received power measurements issued at judiciously placed on-body nodes. Light calibration procedures (e.g., based on the full-scale dynamics of observed measurements) and joint absolute position/orientation estimation algorithms then enable to cover both individual/non-cooperative and collective/cooperative navigation needs. The performance is assessed by means of field experiments with IEEE 802.15.4-compliant integrated devices operating at 2.4 GHz and an optical motion capture system delivering the ground truth reference. On this occasion, our proposal is shown to be resilient against mobile Non-line of Sight (NLoS) situations (e.g., in crowded environments).

A novel photonic analog-to-digital converter (ADC) architecture tailored for the localization of transmitters employing ultra-wide band (UWB) radio technology is proposed and experimentally demonstrated in this paper. The proposed photonic-ADC architecture comprises several parallel branches each including an electro-optic sensor at different spatial locations capturing UWB signals simultaneously (sub-picosecond resolution). A single optical source is required in this architecture for all electro-optic sensors and also a single processing unit is needed to process the optically sampled data, thus simplifying the system implementation. A five-branch photonic-ADC has been developed for the experimental demonstration. The laboratory measurements demonstrate the successful detection and localization of fully-standard UWB transmitters as in WiMedia specification for very-low power radio signals (-65 dBm received power) captured. A mean three-dimensional positioning error of 48.5 cm with 15 cm standard deviation is achieved.