Phillip Tomé

Accommodation of NLOS for ultra-wideband TDOA localization in single- and multi-robot systems

Ultra-wideband (UWB) localization is one of the most promising indoor localization methods. Yet, non-line-of-sight (NLOS) positioning scenarios can potentially cause significant localization errors and remain a challenge. In this work, we propose a novel, probabilistic UWB TDOA error model which explicitly takes into account NLOS. In order to validate our approach systematically in a real world setup, we leverage the utility of a group of mobile robots, and introduce our error model into a real-time localization framework run onboard the robots. We subsequently extend our framework by employing a collaborative localization strategy which enables the sharing of inter-robot, relative position observations. Our experimental results show how the novel TDOA error model is able to improve localization performance when information on the LOS/NLOS path condition is available. These results are complemented by additional experiments which show how a collaborative team of robots is able to significantly improve localization performance when no information on the LOS/NLOS path condition is available.

Implementation and performance of a GPS/INS tightly coupled assisted PLL architecture using MEMS inertial sensors.

The use of global navigation satellite system receivers for navigation still presents many challenges in urban canyon and indoor environments, where satellite availability is typically reduced and received signals are attenuated. To improve the navigation performance in such environments, several enhancement methods can be implemented. For instance, external aid provided through coupling with other sensors has proven to contribute substantially to enhancing navigation performance and robustness. Within this context, coupling a very simple GPS receiver with an Inertial Navigation System (INS) based on low-cost micro-electro-mechanical systems (MEMS) inertial sensors is considered in this paper. In particular, we propose a GPS/INS Tightly Coupled Assisted PLL (TCAPLL) architecture, and present most of the associated challenges that need to be addressed when dealing with very-low-performance MEMS inertial sensors. In addition, we propose a data monitoring system in charge of checking the quality of the measurement flow in the architecture. The implementation of the TCAPLL is discussed in detail, and its performance under different scenarios is assessed. Finally, the architecture is evaluated through a test campaign using a vehicle that is driven in urban environments, with the purpose of highlighting the pros and cons of combining MEMS inertial sensors with GPS over GPS alone.

UWB-based Local Positioning System: From a small-scale experimental platform to a large-scale deployable system

A few years ago an experimental platform was designed and built in order to demonstrate the feasibility of Ultra-Wideband (UWB) technology applied to indoor positioning. This small-scale demonstrator proved to be a valuable research tool with the flexibility to study, test and assess the performance of various system architectures and signal processing algorithms.

Low power ASIC transmitter for UWB-IR radio communication and positioning

This paper describes a low power Ultra-Wideband Impulse Radio (UWB-IR) Application Specific Integrated Circuit (ASIC) transmitter implemented in UMC 0.18 µm. This transmitter has been designed for low data rate communication applications and indoor positioning systems. It is powered by 1.8 V and its current consumption is 20 mA during pulse transmission and lower than 45 µA the rest of the time. This leads to an average power for the transmitter of less than 85 µW for a 288-pulse burst at a burst repetition rate of 1 Hz. The center frequency and bandwidth of the pulse generated by this transmitter are compliant with the current international regulations (FCC/ECC).

Improving pedestrian dynamics modelling using fuzzy logic

The complementary nature of MEMS based pedestrian dead-reckoning (PDR) navigation and GNSS (Global Navigation Satellite System) has long been recognized. The advantages are quite clear for those applications requiring indoor positioning and that, for one reason or another, cannot rely on short-range infrastructure-based positioning systems (e.g. WiFi, UWB) to cope with the lack of availability of GNSS indoors. One such example of application is firemen coordination during emergency interventions.

A New Movement Recognition Technique for Flight Mode Detection

Nowadays, in the aeronautical environments, the use of mobile communication and other wireless technologies is restricted. More specifically, the Federal Communications Commission (FCC) and the Federal Aviation Administration (FAA) prohibit the use of cellular phones and other wireless devices on airborne aircraft because of potential interference with wireless networks on the ground, and with the aircrafts navigation and communication systems. Within this context, we propose in this paper a movement recognition algorithm that will switch off a module including a GSM (Global System for Mobile Communications) device or any other mobile cellular technology as soon as it senses movement and thereby will prevent any forbidden transmissions that could occur in a moving airplane. The algorithm is based solely on measurements of a low-cost accelerometer and is easy to implement with a high degree of reliability.