Antonio Moschitta

A 5.6-GHz UWB Position Measurement System

This paper describes the design and realization of a 5.6-GHz ultrawide-bandwidth-based position measurement system. The system was entirely made using off-the-shelf components and achieves centimeter-level accuracy in an indoor environment. It is based on asynchronous modulated pulse round-trip time measurements. Both system level and realization details are described along with experimental results including estimates of measurement uncertainties.

Characterization and Modeling of an Experimental UWB Pulse-Based Distance Measurement System

This paper presents a distance-measuring system based on the accurate round-trip time-of-flight measurement of single ultrawideband pulses propagating between two transceiver devices. The architectures of two realized devices, which are referred to as the master and the slave, are described. The master device implements the time-interval measuring function by means of a time-to-digital converter (TDC) integrated circuit, whereas the slave acts as a pulse repeater. Both devices are designed for low-cost realization and low-power operations. Furthermore, two pulse-detection modules are described based on signal-threshold and energy detection, respectively. This paper also presents and discusses some experimental results that are obtained from the system prototype. Finally, some numerical simulation results, which provide an explanation for the nonidealities in the observed distance-measuring behavior of the system, are shown.

A survey on time interval measurement techniques and testing methods

The most frequently utilized techniques for precise time interval measurements are discussed. By analyzing the characteristics of both published architectures and commercial Time-to-Digital Converters (TDCs), the most significant testing methods are also considered. Related performance parameters, useful for calibrating such devices and compensating any deviations from the expected behavior, are also identified. Since full standardization activities in this field have not been carried out yet, the proposed results may reduce terminology and definition ambiguities, allowing an easier comparison between different TDC architectures. To this aim, an overall Figure of Merit is also introduced and evaluated for several published TDCs.

A Low-Cost Ultra-Wideband Indoor Ranging System

This paper presents the development of a low-cost indoor ranging technique based on time-of-arrival (TOA) estimation, using short-pulse ultra-wideband (UWB) signals. The realized system includes two identical UWB transceiver devices, in which the receiver section is based on a tunnel diode detector and the pulse generation is performed by a common bipolar transistor driven in avalanche mode. An indirect measurement of the distance between the devices is obtained by measuring the frequency of the generated pulse train. A theoretical model of the system is described, and a statistical analysis is presented, including the closed-form evaluation of the Cramer-Rao lower bound (CRLB) on the distance estimation and showing the asymptotic statistical efficiency of the proposed estimators. Furthermore, the principle of operation of the realized system prototypes is described, along with some implementation issues. Finally, experimental results are shown and discussed.

An Indoor AC Magnetic Positioning System

This paper describes the design and realization of a magnetic indoor positioning system. The system is entirely realized using off-the-shelf components and is based on inductive coupling between resonating coils. Both system-level architecture and realization details are described along with experimental results. The realized system exhibits a maximum positioning error of <;10 cm in an indoor environment over a 3 × 3 m2 area. Extensive experiments in larger areas, in nonline-of-sight conditions, and in unfavorable geometric configurations, show submeter accuracy, thus validating the robustness of the system with respect to other existing solutions.

Performance comparison of advanced techniques for voltage dip detection

Several different approaches for the detection of voltage dips in electic power systems have been proposed in the literature to overcome the limits of the procedure proposed by the International Standard, based on the voltage root mean square. In this paper the most promising of these approaches are compared, by computer simulations, in terms of both statistical performance and response time, which is a critical issue for the development of real-time compensation systems.

Cramer-Rao lower bound for parametric estimation of quantized sinewaves

In this paper, the Crameacuter-Rao Lower Bound (CRLB) for the parametric estimation of quantized sinewaves is analyzed, including the effect of analog-to-digital-converter (ADC) noise. An accurate model based on the statistical properties of quantized data is presented, which takes into account both the effects of the finite ADC resolution and of the quantizer overloading phenomena at a low computational cost. Then, the model is validated by comparing the obtained results with the CRLB based on the ADC uniform noise model

A Simple Ranging System Based on Mutually Coupled Resonating Circuits

In this paper, a ranging technique based on inductive coupling between resonating coils is presented. By exploiting resonance, both a high range and high signal-to-noise ratio at the receiver are achieved. The theoretical background is discussed; a theoretical model is presented; and a practical implementation is illustrated and experimentally validated. It is shown that the proposed technique, implemented using off-the-shelf components, is only moderately sensitive to the effect of conductive objects placed close to the receiver, whereas it proves its effectiveness in an ordinary laboratory setup, achieving a maximum error of <;3 cm over a 5.8-m range. It is thus suitable for indoor positioning applications.

Design and Characterization of a Portable Ultrasonic Indoor 3-D Positioning System

In this paper, an ultrasonic positioning system is presented and characterized, based on the usage of a portable grid of beacons and of a few fixed anchors. Since the beacon grid can be moved to guarantee line-of-sight transmissions, the proposed strategy is potentially suitable for accurate positioning of a mobile object in an environment with a complex geometry. The system was tested experimentally, exhibiting a subcentimeter positioning accuracy in a range up to 4 m.

Low Complexity UWB Radios for Precise Wireless Sensor Network Synchronization

Wireless sensor networks are becoming widely diffused because of the flexibility and scalability they offer. However, distributed measurements are significant only if the readout is coupled to time information. For this reason, network-wide time synchronization is the main concern. The objective of this paper is to exploit a very simple hardware implementation of an IR-UWB radio for realizing an accurate synchronization system for wireless sensors. The proposed solution relies on commercial-off-the-shelf discrete electronic components (rather than on specialized transceivers). It is designed for providing accurate timestamping of the packet time of arrival (TOA) to an adder-based tunable clock, which tracks the network time reference. The comprehensive set of experimental results based on prototypes, shows a TOA detection error with a standard deviation well below 1 ns. On the other hand, in the FPGA-based prototype, the synchronization performance reaches an overall synchronization error of few nanoseconds. Finally, in order to highlight the tradeoff between timestamping accuracy, clock stability, and synchronization performance, some additional simulations have been carried out: a synchronization error in the order of 1 ns is possible, if good local oscillator sources are available in the nodes and if the adjustable clock has a sufficient resolution.