Guido De Angelis

A detection method for parametric signals in noise is proposed. Since the detection is performed by processing 1-bit quantized data, the method can be implemented using low-complexity systems. A generalized likelihood ratio test (GLRT) is derived, which is based on parametric estimates of the amplitude and phase of a periodic signal. The asymptotic properties of the test statistic of the GLRT are derived analytically. Such properties are then employed to study the performance of the detector… Show more

A detection method for parametric signals in noise is proposed. Since the detection is performed by processing 1-bit quantized data, the method can be implemented using low-complexity systems. A generalized likelihood ratio test (GLRT) is derived, which is based on parametric estimates of the amplitude and phase of a periodic signal. The asymptotic properties of the test statistic of the GLRT are derived analytically. Such properties are then employed to study the performance of the detector, by comparing them with the clairvoyant detector. The performance of the developed detector is evaluated by numerical simulations and validated by a simple experimental setup. The impact of noise and threshold selection on detection performance and the promptness of response are also numerically analyzed. Given its implementation simplicity, the proposed detector does not require high-resolution circuitry nor computationally intensive hardware. Therefore, it could enable novel applications in the Internet-of-Things domain, such as low-cost radar systems and sensor networks. Show less

This article presents a compact measurement system for electrochemical impedance spectroscopy (EIS) on lithium-ion battery (LIB). The system is composed of a vector impedance analyzer (VIA) and state parameter estimation. The VIA architecture is based on delta-sigma digital-to-analog and analog-to-digital conversions to achieve the compactness, low-power consumption, and high resolution required to be potentially integrated within a battery cell. The estimation of state parameters is based on… Show more

This article presents a compact measurement system for electrochemical impedance spectroscopy (EIS) on lithium-ion battery (LIB). The system is composed of a vector impedance analyzer (VIA) and state parameter estimation. The VIA architecture is based on delta-sigma digital-to-analog and analog-to-digital conversions to achieve the compactness, low-power consumption, and high resolution required to be potentially integrated within a battery cell. The estimation of state parameters is based on equivalent circuit models and the solution of nonlinear optimization problems. The proposed measurement system aims at the integration of complex measurement features directly into the battery cell to allow online and real-time diagnostic of the battery cell. A prototype of the compact measurement system was realized to assess the proposed approach. Experimental results are provided and validated by comparison with a reference laboratory instrument, showing good agreement. The VIA prototype is experimentally tested in both the online monitoring and aging monitoring of a commercial LIR2032 LIB cell. The modeling approach is applied to the experimental data provided by the VIA prototype, showing a good fit of the data. Moreover, parameters of the equivalent circuit models are extracted from the experimental data provided by the VIA prototype and identify trends related to the state of charge of the battery. Show less

Abstract—We present an in-circuit approach for estimating the LC parameter in coupled resonant circuits. The theoretical background is discussed by presenting the models and performing a numerical sensitivity analysis. The method for estimating LC is based on noisy frequency response function measurements of the coupled resonant circuit. A practical implementation is presented and employed to validate the proposed method. Experimental results show that the proposed method provides an estimate… Show more

Abstract—We present an in-circuit approach for estimating the LC parameter in coupled resonant circuits. The theoretical background is discussed by presenting the models and performing a numerical sensitivity analysis. The method for estimating LC is based on noisy frequency response function measurements of the coupled resonant circuit. A practical implementation is presented and employed to validate the proposed method. Experimental results show that the proposed method provides an estimate of LC with a deviation of less than 4% with respect to LCR meter measurement results. Show less

In this paper, modeling of inductive coupling between circular coils is analyzed. We present a system for
measuring the mutual inductance and the magnetic flux between resonant coils. We investigate the accuracy and precision against data obtained through the FastHenry2 simulation software and through experiments, when these are available (Pasku et al., 2017). The theoretical background is discussed, theoretical models are presented, and their properties are compared to those of other… Show more

In this paper, modeling of inductive coupling between circular coils is analyzed. We present a system for
measuring the mutual inductance and the magnetic flux between resonant coils. We investigate the accuracy and precision against data obtained through the FastHenry2 simulation software and through experiments, when these are available (Pasku et al., 2017). The theoretical background is discussed, theoretical models are presented, and their properties are compared to those of other published models. A practical implementation is illustrated and employed to validate the considered numerical models. Obtained results demonstrate that the proposed modeling and experimental setup provide high-accuracy measurements of the induced voltage. Field measurements validate the considered numerical models with a discrepancy of less than 10% with respect to measurement results. Show less

n this paper, two techniques for accurate estimation of the moment of magnetic dipole are proposed. The achievable accuracy is investigated, as a function of measurement noise affecting estimation of magnetic field cartesian components, and with respect to the induced rms voltage. The proposed techniques are validated both via simulations and experiments.

Identification of RLC circuital parameters is investigated. We present a method for estimating the parameters of the circuit transfer function. The theoretical background is discussed, theoretical models are presented and experimentally validated. A practical implementation is presented and employed to validate the considered numerical models. Numerical and experimental results demonstrate that the proposed system provides a good accuracy measurement of the parameters of the resonant circuit… Show more

Identification of RLC circuital parameters is investigated. We present a method for estimating the parameters of the circuit transfer function. The theoretical background is discussed, theoretical models are presented and experimentally validated. A practical implementation is presented and employed to validate the considered numerical models. Numerical and experimental results demonstrate that the proposed system provides a good accuracy measurement of the parameters of the resonant circuit. The experimental results validate the considered numerical models with a discrepancy of less than 10% with respect to measurement models. Show less

n this paper, we consider magnetic positioning and tracking of objects and provide a comparison of the characteristics of two major measurement models: the magnetic dipole model and the mutual inductance model. The numerical results obtained by applying these models to a short-range position measurement application, with a maximum operating distance of approximately 50 cm, are compared. Based on the results of this comparison, a prototype 9-sensor array is developed, experimental tests are… Show more

n this paper, we consider magnetic positioning and tracking of objects and provide a comparison of the characteristics of two major measurement models: the magnetic dipole model and the mutual inductance model. The numerical results obtained by applying these models to a short-range position measurement application, with a maximum operating distance of approximately 50 cm, are compared. Based on the results of this comparison, a prototype 9-sensor array is developed, experimental tests are performed, and extensive measurement results are presented. Outcomes show the feasibility of tracking the position and orientation of a mobile coil in real time with a median positioning error below 1 cm and a worst-case error of about 2 cm and 11 degrees inside a spatial region of 30 × 30 × 30 cm³ operational volume. Show less

This paper proposes an analysis of the quasistationary magnetic field generated by coils and its applicability to 3-D short-range positioning scenarios. Starting from a theoretical background, an approximation of the induced voltage in a sensor coil is developed and analyzed. Then, the design and performance of a short-range magnetic field-based positioning system is described. The system is realized by using three-axis field generating coils and a three-axis sensor coil. It uses resonance… Show more

This paper proposes an analysis of the quasistationary magnetic field generated by coils and its applicability to 3-D short-range positioning scenarios. Starting from a theoretical background, an approximation of the induced voltage in a sensor coil is developed and analyzed. Then, the design and performance of a short-range magnetic field-based positioning system is described. The system is realized by using three-axis field generating coils and a three-axis sensor coil. It uses resonance properties to decrease current and power consumption requirements. The system is targeted for simple and low-cost applications, requiring subdecimeter accuracies over short ranges of approximately a couple of meters. The realized prototype, validated through in-field measurements, features a positioning error in the order of 4-5 cm over an area of 1.15 m × 1.55 m × 0.8 m. Show less

Vehicle recognition is one of the main challenges in Intelligent Transportation Systems (ITS). The need to recognize the vehicle type can help insurance companies, public safety organizations, infomobility, and policy-makers in general. In this paper, we propose a vehicle recognition system based on speed estimation, vehicle length estimation and classification of the vehicle type. We developed a real time system for vehicle recognition based on four steps: a storage of the magnetic signature… Show more

Vehicle recognition is one of the main challenges in Intelligent Transportation Systems (ITS). The need to recognize the vehicle type can help insurance companies, public safety organizations, infomobility, and policy-makers in general. In this paper, we propose a vehicle recognition system based on speed estimation, vehicle length estimation and classification of the vehicle type. We developed a real time system for vehicle recognition based on four steps: a storage of the magnetic signature of the vehicle, speed estimation, estimation of the length of the vehicle and vehicle recognition. The latter has been realized through matching between the measured waveform with information in a database containing magnetic signatures of vehicles. Matching was realized using the Dynamic Time Warping (DTW) method. Experimental results involving 10 vehicles and 50 trials show successful identification of approximately 98% of the considered vehicles. Show less

The influence of the environmental configuration on ac magnetic distance and position measurement systems, which are based on inductive coupling of tuned resonators, is experimentally analyzed. The main aspects that affect the accuracy of such systems are the conductivity of the terrain and the presence of metallic materials near the resonators. It is shown that such aspects are frequency dependent, and a tradeoff is to be considered between the maximum operating range and the error. Moreover… Show more

The influence of the environmental configuration on ac magnetic distance and position measurement systems, which are based on inductive coupling of tuned resonators, is experimentally analyzed. The main aspects that affect the accuracy of such systems are the conductivity of the terrain and the presence of metallic materials near the resonators. It is shown that such aspects are frequency dependent, and a tradeoff is to be considered between the maximum operating range and the error. Moreover, a strategy to detect if the measurement results are corrupted by the environmental configuration is presented. The analysis is then extended to a positioning scenario where the prototype of a magnetic positioning system (MPS) is deployed and a comparison with a commercial ultrawideband (UWB) system is performed. The results show that the MPS performance is comparable with the commercial UWB system, leading to a mean positioning error of the order of 0.6 m when using an extended Kalman filter-based positioning algorithm. Show less

A method for crosstalk detection and removal in multichannel time-of-arrival measurement systems is proposed. The method, based on low-complexity processing of cross-correlation results, is evaluated by numerical simulations and experimental characterization. Results show the capability to detect and remove crosstalk by processing the signals acquired by two mutually-interfering electrical channels. The validation, carried out on a time-of-arrival positioning system, yielded centimeter-level… Show more

A method for crosstalk detection and removal in multichannel time-of-arrival measurement systems is proposed. The method, based on low-complexity processing of cross-correlation results, is evaluated by numerical simulations and experimental characterization. Results show the capability to detect and remove crosstalk by processing the signals acquired by two mutually-interfering electrical channels. The validation, carried out on a time-of-arrival positioning system, yielded centimeter-level accuracy in the presence of relevant inter-channel interference. The proposed method is of a general nature and is not limited only to positioning scenarios. Show less

This paper proposes an analysis of the quasi-stationary magnetic field generated by coils and its applicability to 3D positioning applications. Starting from a theoretical background, an approximation of the induced voltage in a sensor coil is developed and analyzed. In particular, the introduced approximation error is shown to be lower than 5 mm over a 20 m range. Finally, the developed model is compared against a well-established theoretical model developed in the literature and against… Show more

This paper proposes an analysis of the quasi-stationary magnetic field generated by coils and its applicability to 3D positioning applications. Starting from a theoretical background, an approximation of the induced voltage in a sensor coil is developed and analyzed. In particular, the introduced approximation error is shown to be lower than 5 mm over a 20 m range. Finally, the developed model is compared against a well-established theoretical model developed in the literature and against in-field measurements in the range 0.5 m to 5 m. Results show that the developed model may be suitable for magnetic field based distance measurements in low complexity 3D positioning applications. Show less

This paper describes the design and realization of a magnetic positioning system (MPS) integrated with a global positioning system (GPS) receiver. The GPS receiver is composed of hardware and software sections that can be integrated with the MPS. Both system-level architecture and realization details are described along with experimental results. The realized prototype measurement system exhibits a maximum positioning error of less than 5 m and an average error of less… Show more

This paper describes the design and realization of a magnetic positioning system (MPS) integrated with a global positioning system (GPS) receiver. The GPS receiver is composed of hardware and software sections that can be integrated with the MPS. Both system-level architecture and realization details are described along with experimental results. The realized prototype measurement system exhibits a maximum positioning error of less than 5 m and an average error of less than 3 m, thus providing better performance than a stand-alone GPS consumer receiver.
Further, the system is tested in two different scenarios, showing repeatable performance. A practical system implementation is presented, which can be employed in applications that require power-efficiency and low-cost operation. Such an implementation is tested experimentally, providing results that are comparable to those of the preliminary prototype, thus validating the proposed approach. Show less

This paper describes the design and the realization of a low-frequency ac magnetic-field-based indoor positioning system (PS). The system operation is based on the principle of inductive coupling between wire loop antennas. Specifically, due to the characteristics of the ac artificially generated magnetic fields, the relation between the induced voltage and the distance is modeled with a linear behavior in a bilogarithmic scale when a configuration with coplanar, thus equally oriented, antennas… Show more

This paper describes the design and the realization of a low-frequency ac magnetic-field-based indoor positioning system (PS). The system operation is based on the principle of inductive coupling between wire loop antennas. Specifically, due to the characteristics of the ac artificially generated magnetic fields, the relation between the induced voltage and the distance is modeled with a linear behavior in a bilogarithmic scale when a configuration with coplanar, thus equally oriented, antennas is used. In this case, the distance between a transmitting antenna and a receiving one is estimated using measurements of the induced voltage in the latter. For a high operational range, the system makes use of resonant antennas tuned at the same nominal resonant frequency. The quality factors act as antenna gain increasing the amplitude of the induced voltage. The low-operating frequency is the key factor for improving robustness against nonline-of-sight (NLOS) conditions and environment influences with respect to other existing solutions. The realized prototype, which is implemented using off-the-shelf components, exhibits an average and maximum positioning error, respectively, lower than 0.3 and 0.9 m in an indoor environment over a large area of 15 m × 12 m in NLOS conditions. Similar performance is obtained in an outdoor environment over an area of 30 m × 14 m. Furthermore, the system does not require any type of synchronization between the nodes and can accommodate an arbitrary number of users without additional infrastructure. Show less

Time-interval measurement systems using threshold detectors experience severe performance degradation in the presence of noise and interference. This paper describes an approach to robust measurement of time intervals in the presence of interference. This approach is based on modeling the distribution of the measurement results as a Gaussian–uniform mixture. A batch maximum-likelihood and a recursive particle filtering estimator are implemented, which incorporate the… Show more

Time-interval measurement systems using threshold detectors experience severe performance degradation in the presence of noise and interference. This paper describes an approach to robust measurement of time intervals in the presence of interference. This approach is based on modeling the distribution of the measurement results as a Gaussian–uniform mixture. A batch maximum-likelihood and a recursive particle filtering estimator are implemented, which incorporate the above model. The accuracy and robustness of the approach are evaluated by numerical simulations and by comparison with the Cramér–Raolower bound. Finally, as a case study, the approach is applied to the experimental data obtained from an in-house developed ultrawideband time-interval measurement system. Show less

Motivated by the emergence of the Internet of Things (IoT), and by the importance that location information has on many complex systems scenarios, we propose a hybrid scheme for user positioning in an urban scenario. The system uses both a Global Navigation Satellite System (GNSS) and a Magnetic Positioning System (MPS). To maintain receiver complexity and cost at a minimum, the location scheme combines the MPS technique and GNSS measurements. A Kalman filter algorithm is used as the data… Show more

Motivated by the emergence of the Internet of Things (IoT), and by the importance that location information has on many complex systems scenarios, we propose a hybrid scheme for user positioning in an urban scenario. The system uses both a Global Navigation Satellite System (GNSS) and a Magnetic Positioning System (MPS). To maintain receiver complexity and cost at a minimum, the location scheme combines the MPS technique and GNSS measurements. A Kalman filter algorithm is used as the data integration mechanism over the time axis. Results demonstrate that the use of a local MPS provides increased location coverage, without service interruptions, when the number of visible satellites is inadequate. The obtained accuracy in the indoor environment is better than meter-level, thus fulfilling the requirements of many hybrid outdoor/indoor positioning. Show less

This paper addresses the problem of adaptive noise cancellation in a multi-channel system. The proposed canceller is a recursive system, based on the Least Mean Squares filter (LMS). This method is analyzed by simulations and experimental results are given. Specifically, it is shown that this technique can improve the accuracy of ultrasound ranging and positioning systems using multichannel receivers.

This paper describes the design and realization of a Magnetic Positioning System (MPS) integrated with a Global Positioning System (GPS) receiver. The GPS receiver is composed of a hardware section and a software section that can integrate with the MPS. Both system-level architecture and realization details are described along with experimental results. The realized measurement system exhibits a maximum positioning error of less than 5 m, and an average error of less than 3 m, thus providing… Show more

This paper describes the design and realization of a Magnetic Positioning System (MPS) integrated with a Global Positioning System (GPS) receiver. The GPS receiver is composed of a hardware section and a software section that can integrate with the MPS. Both system-level architecture and realization details are described along with experimental results. The realized measurement system exhibits a maximum positioning error of less than 5 m, and an average error of less than 3 m, thus providing better performance than a standalone GPS consumer receiver. Further, the system has been tested in two different scenarios, showing repeatable performance. Show less

The influence of the environmental configuration on AC magnetic distance-measurement systems, which are based on inductive coupling of tuned resonators, is experimentally analyzed. The main aspects that affect accuracy in such systems are the conductivity of the terrain and the presence of metallic materials near the resonators. It is shown that such aspects are frequency-dependent, and a tradeoff is to be considered between maximum operating range and error. Moreover, a strategy to detect if… Show more

The influence of the environmental configuration on AC magnetic distance-measurement systems, which are based on inductive coupling of tuned resonators, is experimentally analyzed. The main aspects that affect accuracy in such systems are the conductivity of the terrain and the presence of metallic materials near the resonators. It is shown that such aspects are frequency-dependent, and a tradeoff is to be considered between maximum operating range and error. Moreover, a strategy to detect if measurement results are corrupted by environmental configuration is presented. This strategy is crucial to improve the integrity of positioning systems. Show less

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… Show more

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. Show less

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 less than 10 cm in an indoor environment over a 3×3 m2 area.

This paper describes a robust method for calibrating radio-frequency ranging systems in indoor environments. An approach for outlier rejection is proposed, based on modeling the distribution of the distance-measurement results as a Gaussian-uniform mixture. Using this model, a batch maximum likelihood and a recursive particle filtering estimator are implemented. The accuracy and robustness of the approach are evaluated by numerical simulations and by comparison with the Cramer-Rao Lower Bound… Show more

This paper describes a robust method for calibrating radio-frequency ranging systems in indoor environments. An approach for outlier rejection is proposed, based on modeling the distribution of the distance-measurement results as a Gaussian-uniform mixture. Using this model, a batch maximum likelihood and a recursive particle filtering estimator are implemented. The accuracy and robustness of the approach are evaluated by numerical simulations and by comparison with the Cramer-Rao Lower Bound. Finally, the approach is validated on experimental data obtained from a in-house developed Ultra-Wideband indoor ranging system. Show less

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… Show more

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. Show less

In this paper, the Cramér-Rao Lower Bound (CRLB) on the variance of time interval duration estimators is derived for synchronous Time-to-Digital (TDC) converters, based on a coarse counter, keeping into account the effect of noise affecting the TDC clock period. The model has been validated using Montecarlo analysis. By comparing the CRLB to the variance of the TDC output, also theoretically modeled together with the estimator mean value and bias, the statistical efficiency of the considered… Show more

In this paper, the Cramér-Rao Lower Bound (CRLB) on the variance of time interval duration estimators is derived for synchronous Time-to-Digital (TDC) converters, based on a coarse counter, keeping into account the effect of noise affecting the TDC clock period. The model has been validated using Montecarlo analysis. By comparing the CRLB to the variance of the TDC output, also theoretically modeled together with the estimator mean value and bias, the statistical efficiency of the considered TDC architecture has been demonstrated. Show less

The purpose of this paper is to evaluate the performance of a sequential Generalized Likelihood Ratio Test (GLRT) for the detection of possible faults occurring on the airspeed velocity sensor of an UAV based on real flight data from the WVU YF-22 research aircraft. In the first part of the paper a novel Analytical Redundancy based method is proposed to provide a real-time estimation of the airspeed velocity to be use later for fault detection purpose. In this approach, assuming the… Show more

The purpose of this paper is to evaluate the performance of a sequential Generalized Likelihood Ratio Test (GLRT) for the detection of possible faults occurring on the airspeed velocity sensor of an UAV based on real flight data from the WVU YF-22 research aircraft. In the first part of the paper a novel Analytical Redundancy based method is proposed to provide a real-time estimation of the airspeed velocity to be use later for fault detection purpose. In this approach, assuming the availability of the state and input signals governing the UAV dynamics, the angle of attack equation is rearranged as a quadratic equation in V(k) which is solved to provide estimates of the airspeed. The parameters governing the airspeed equation are identified via LS optimization from a record of flight data. The error signal between the measured airspeed velocity V(k) and its estimation provides the residual signal r(k) that is used for fault detection. In order to apply a sequential GLRT it was necessary to design a residual whitening filter so that rigorous statistical tests can be performed on the Gaussian whitened signal. Under this assumption it is possible to compute the probability of false alarms. In the experimental part, given a probability of false alarm the detectability of hard and soft failures was studied by varying the amplitude and rate of faults artificially injected on the experimental flight data. The experimental results confirm the capabilities of the proposed method to cope with the important problem of the airspeed sensor fault detection. Show less

In this paper, a ranging technique based on inductive coupling between resonating coils is presented. The theoretical background is discussed, and a practical implementation is illustrated and experimentally validated. It is shown that the proposed technique, implemented using off the shelf components, features both a good range and a fair resilience to multipath, being suitable for indoor positioning applications.

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.

This paper proposes a hybrid scheme for user positioning in an urban scenario using both a Global Navigation Satellite System (GNSS) and a mobile cellular network. To maintain receiver complexity (and costs) at a minimum, the location scheme combines the time-difference-of-arrival (TDOA) technique measurements obtained from the cellular network with GNNS pseudorange measurements. The extended Kalman filter (EKF) algorithm is used as a data integration system over the time axis. Simulated… Show more

This paper proposes a hybrid scheme for user positioning in an urban scenario using both a Global Navigation Satellite System (GNSS) and a mobile cellular network. To maintain receiver complexity (and costs) at a minimum, the location scheme combines the time-difference-of-arrival (TDOA) technique measurements obtained from the cellular network with GNNS pseudorange measurements. The extended Kalman filter (EKF) algorithm is used as a data integration system over the time axis. Simulated results, which are obtained starting from real measurements, demonstrate that the use of cellular network data may provide increased location accuracy when the number of visible satellites is not adequate. In every case, the obtained accuracy is within the limits required by emergency location services, e.g., Enhanced 911 (E911). Show less

A method is proposed for position estimation from non line of sight time difference of arrivals (TDOA) measurements. A general measurement model for TDOA accounting for non line of sight conditions is developed; then, several simplifying working assumptions regarding this model are discussed to allow the efficient implementation of a particle filter localization algorithm. This algorithm is tested and compared with an extended Kalman filter procedure, both in simulation, generating artificial… Show more

A method is proposed for position estimation from non line of sight time difference of arrivals (TDOA) measurements. A general measurement model for TDOA accounting for non line of sight conditions is developed; then, several simplifying working assumptions regarding this model are discussed to allow the efficient implementation of a particle filter localization algorithm. This algorithm is tested and compared with an extended Kalman filter procedure, both in simulation, generating artificial measures, and with real data. Show less

In this paper, a pulse-UWB system based on the Round-Trip-Time (RTT) ranging approach is considered. RTT has the advantage of not requiring strict time synchronization between radio transceivers. However, the fundamental issue is the determination and compensation of the latency introduced by the responder devices. This aspect introduces the need for calibration of the system.The principal contribution of the present paper is the analysis of the calibration procedure, focused on its influence… Show more

In this paper, a pulse-UWB system based on the Round-Trip-Time (RTT) ranging approach is considered. RTT has the advantage of not requiring strict time synchronization between radio transceivers. However, the fundamental issue is the determination and compensation of the latency introduced by the responder devices. This aspect introduces the need for calibration of the system.The principal contribution of the present paper is the analysis of the calibration procedure, focused on its influence on accuracy. In particular, a calibration procedure based on outlier rejection and data fitting is proposed. Its effect is evaluated by processing experimental data obtained from an UWB positioning system. Such an evaluation could be used to establish a trade-off between the time and cost of the preliminary calibration procedure and the target accuracy required by the application. Show less

The paper describes the most recent experiences of the DICA Laboratory of Geomatics on integrated positioning systems based on low cost sensors. The study is finalised to an application for the real time monitoring and managing of a fleet of buses for public and scholastic transport service. The hardware and software components selected for the implementation on the vehicles have been tested to verify the correct operation of the system. The results have been compared with those of more… Show more

The paper describes the most recent experiences of the DICA Laboratory of Geomatics on integrated positioning systems based on low cost sensors. The study is finalised to an application for the real time monitoring and managing of a fleet of buses for public and scholastic transport service. The hardware and software components selected for the implementation on the vehicles have been tested to verify the correct operation of the system. The results have been compared with those of more advanced and complex systems including inertial sensors, carrier phase, GLONASS, code and code/phase RTCM corrections supplied by a GNSS permanent network, and post processing solutions. The tests have been performed in critical environment such as urban areas and roads with vegetation on the borders. The results of the tests permit to analyse the problem of the GNSS outages due to physical obstructions, and their reduction by means of low cost inertial devices (MEMS). Show less

This paper proposes a simplified acquisition system for finding and identifying Base Stations (BSs) in visibility in the framework of a CDMA wireless positioning system, based on IS-95 cellular standard. The problem of having more than one BS in the same PN code acquisition system makes it necessary to discriminate between correct detection and false alarm events. Since IS-95 uses the same PN sequence for all BSs, but with different code offsets, it is possible to use a cross-correlation… Show more

This paper proposes a simplified acquisition system for finding and identifying Base Stations (BSs) in visibility in the framework of a CDMA wireless positioning system, based on IS-95 cellular standard. The problem of having more than one BS in the same PN code acquisition system makes it necessary to discriminate between correct detection and false alarm events. Since IS-95 uses the same PN sequence for all BSs, but with different code offsets, it is possible to use a cross-correlation technique to estimate both code and frequency offsets of several BSs at once. Time-Difference-Of-Arrival (TDOA) technique is used by the Mobile Station (MS) to geolocate itself. The positioning estimate is found to be stable in time and with a precision compatible with that required by emergency services, such as Enhanced 911 (E911). Show less

This paper describes the operation principle and experimental results of a low cost positioning system based on low frequency magnetic fields. In particular, the system prototype is realized using low cost microcontroller based boards combined with off-the-shelf components and is tested over an area of approximately 50 m2. Experimental results show a mean positioning error lower than 0.2 m and a maximum positioning error lower than 0.7 m.

In this paper, a technique for accurate estimation of the moment of magnetic dipole is proposed. The achievable accuracy is investigated, as a function of measurement noise affecting estimation of magnetic field cartesian components. The proposed technique is validated both via simulations and experimentally.

In this paper, a technique for modeling propagation of ultrawideband (UWB) signals in indoor or outdoor environments is proposed, supporting the design of a positioning systems based on round-trip-time (RTT) measurements and on a particle filter. By assuming that nonlinear pulses are transmitted in an additive white Gaussian noise channel and are detected using a threshold-based receiver, it is shown that RTT measurements may be affected by non-Gaussian noise. RTT noise properties are analyzed,… Show more

In this paper, a technique for modeling propagation of ultrawideband (UWB) signals in indoor or outdoor environments is proposed, supporting the design of a positioning systems based on round-trip-time (RTT) measurements and on a particle filter. By assuming that nonlinear pulses are transmitted in an additive white Gaussian noise channel and are detected using a threshold-based receiver, it is shown that RTT measurements may be affected by non-Gaussian noise. RTT noise properties are analyzed, and the effects of non-Gaussian noise on the performance of an RTT-based positioning system are investigated. To this aim, a classical least-squares estimator, an extended Kalman filter, and a particle filter are compared when used to detect a slowly moving target in the presence of the modeled noise. It is shown that, in a realistic indoor environment, the particle filter solution may be a competitive solution, at a price of increased computational complexity. Experimental verifications validate the presented approach. Show less

his paper provides an introductory survey on the various systems that exploit magnetic fields for positioning. Such systems find applications in those scenarios, both indoors and outdoors, where global navigation satellite systems are not available or fail to provide information with the needed accuracy. While the main idea of using electromagnetic fields to provide position information dates back to the past century, new application-led research on this topic has emerged in recent years… Show more

his paper provides an introductory survey on the various systems that exploit magnetic fields for positioning. Such systems find applications in those scenarios, both indoors and outdoors, where global navigation satellite systems are not available or fail to provide information with the needed accuracy. While the main idea of using electromagnetic fields to provide position information dates back to the past century, new application-led research on this topic has emerged in recent years. Results have expanded the application range of magnetic positioning technologies and form now a domain of knowledge that enables realization of positioning systems applicable to indoor and outdoor environments. This paper provides the main characteristics of different positioning systems with focus on those solutions that are based on low-frequency magnetic fields. Some background theory is presented and positioning results from the literature are analyzed and compared. Show less