Harris Perakis | National Technical University of Athens (original) (raw)

Papers by Harris Perakis

The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences

(paolo.dabove, vincenzo.dipietra)@polito.it

<p>The release of Android Raw GNSS Measurements API in mid-2016 has enabled the rec... more <p>The release of Android Raw GNSS Measurements API in mid-2016 has enabled the reconstruction of pseudorange, carrier-phase, Doppler and carrier-to-noise density (CN0) observables in low-cost, smart devices.  This technical development has opened the door to numerous applications that necessitate increased Position-Velocity-Time (PVT) quality metrics.  However, despite the recent advances in the field, deficiencies inherent to smartphones GNSS antenna and chipset, still account for excessive biases in the raw GNSS observables and for severe multipath effects in the satellite signal.  RAIM (Receiver Autonomous Integrity Monitoring) techniques is one way to monitor and increase the performance of the PVT solution of a GNSS receiver.  It is an augmentation method to detect and eventually reject anomalous (blunders or outliers) measurements and compute protection levels that bound position errors to preset limits.</p> <p>The implementation of RAIM technique to smartphone GNSS data is very limited and confined only to static positioning scenarios.  This study presents the results obtained from the testing of the classic RAIM technique in a series of kinematic positioning trials in urban environment using two cotemporary smartphone devices (i.e., Xiaomi Mi 8 and One Plus Nord2 5G).  In order to reconstruct a real use case, the smartphones were mounted on the vehicle dashboard.  The reference trajectory was obtained using a tactical grade GNSS/IMU system (NovAtel® PwrPak7, iMAR IMU-FSAS) fixed on the NTUA test vehicle roof-top sensor platform.  </p> <p>At a pre-processing stage the raw GNSS data have undergone through a Hatch filer.  This step allows to smooth iteratively the noisy code pseudorange measurements using the precise (but ambiguous) phase carrier measurements.  Data analysis includes two processing strategies. We employ the PANG-NAV open-source software released by LabPANG (PArthenope Navigation Group Laboratory) to compute the SPP (Single Point Positioning) solution in two ways.  We produce the standard and the RAIM-based SPP solution using different parameter setups.  The paper presents quantitative results and comparisons between the two smartphone-based solutions and the reference trajectory, and reveal the potential (benefits and limitations) of using the RAIM technique for smartphone positioning.</p>

<p>The recent advances in Information Technology (IT) and Micro-Electromechanical S... more <p>The recent advances in Information Technology (IT) and Micro-Electromechanical Systems (MEMS) technologies and their global adoption in contemporary smartphone and PDA devices enables the introduction of novel approaches for indoor positioning applications that combine multi-sensor capabilities.</p> <p>In this regard, Radio-frequency (RF), high accuracy ranging technologies operating in the Ultra-Wide Band (UWB) spectrum have recently been introduced in contemporary smartphone devices. Additionally, the adoption of Wi-Fi RTT technology in the most recent smartphone devices facilitates Peer-to-Infrastructure (P2I) medium level accuracy ranging in a widespread and seamless manner together with the standard web access functionality. Applications requiring absolute positioning of moderate to low accuracy may depend on Wi-Fi RTT-only systems, while high-accuracy UWB ranging would facilitate cases demanding safety-critical proximity reliant standards. Positioning architectures optimally utilizing these Two-Way Ranging (TWR) technologies may provide increased coverage and flexibility for indoor conditions in cases that a higher level of accuracy and availability is required.</p> <p>This study aims at utilizing RF-based range measurements and to combine them optimally into a Pedestrian to Infrastructure (P2I), as well as, Pedestrian to Pedestrian (P2P) collaborative functional model aided by inertial measurements for indoor positioning. The implementation of the proposed approach utilizes simulation-based TWR data from four infrastructure nodes to four roving nodes, whereas operational elements for each technology, such as sampling rate, data formatting and communications scheduling are taken into account.</p> <p>The distinct working scenarios examined in this study are as follows.  Firstly, we examine separately the performance of the two technological approaches (i.e., Wi-Fi RTT and UWB) for P2I positioning scenarios.  Secondly, we study the performance of the fuse the combined use of these technologies.  For this purpose, we employ a scenario featuring a mixture of Wi-Fi RTT anchor and UWB static rover ranges. Finally, the potential (benefits and limitations) of the inclusion of IMU-based Azimuth information in the KF computation is evaluated for all scenarios. The results obtained from this investigation indicate a potential improvement in position accuracy of the order of 29% and 37% for Wi-Fi RTT/ UWB and Wi-Fi RTT/ UWB/ IMU solutions accordingly.</p>

IEEE Open Journal of Intelligent Transportation Systems

This research is co-financed by Greece and the European Union (European Social Fund-ESF) through ... more This research is co-financed by Greece and the European Union (European Social Fund-ESF) through the Operational Programme Human Resources Development, Education and Lifelong Learning 2014-2020 in the context of the project "Advanced WiFi-RTT Based Localization Techniques for the Development and Testing of Pedestrian behavior Classification" (MIS 5049177).

Proceedings of conference GIS Ostrava 2021 Advances in Localization and Navigation, 2021

Minimizing fuel consumption while maximizing driving performance (i.e., less travel time, increas... more Minimizing fuel consumption while maximizing driving performance (i.e., less travel time, increased safety and less gas emissions) is a key factor for the successful implementation of any transport system. In this regard, monitoring driving behaviour and converting this information into real-time advice to drivers can benefit seriously the performance of transport and mobility services. This paper presents the design and implementation of a prototype system and a BI (Business Intelligence) model for fuel consumption optimization for heavy-duty vehicles. The system consists of an OBDH prototype, various external sensors (including GNSS/INS and environmental ones), and an on-purpose built FMS (Fleet Management System) bus logger. The paper revisits the concept of BI and attempts knowledge transfer from the field of data analytics for business information to a pure engineering problem. Preliminary analyses using real truck trajectory data reveals and quantifies the effect of driving behaviour on fuel consumption while it indicates the potential of the system to transform into an integrated, self-trained driver coaching system.

2021 7th International Conference on Models and Technologies for Intelligent Transportation Systems (MT-ITS), 2021

The volume of freight transport on roads has grown steadily over the years and is expected to inc... more The volume of freight transport on roads has grown steadily over the years and is expected to increase significantly over the next decade. Truck driver coaching systems have proved a key element in boosting efficiency, profitability and safety of the haulage sector whilst contributing to infrastructure asset management objectives. Notwithstanding new, commercial driver coaching systems have shown up recently in the market, still they operate as "black boxes", whilst their functionality and automation level is very limited. Given the enormous numbers of truck fleets currently operating worldwide, the necessity for an adaptable driver coaching system, capable of providing real-time functionality is evident. This study reports the design characteristics and first results from PEGASUS research project aiming at developing a self-trained, unified, driver-coaching system based on geolocation, IoT (Internet of Things) and BI (Business Intelligence) techniques. The system by design aims at reducing operational costs for the truck fleet, improving road safety, as well as contributing to green transportation. In effect, the system has been designed to produce user-friendly, two-way advice to lorry drivers tailored to the road conditions (e.g., geometry, road markings, neighboring vehicles) and operational (e.g., weather, traffic) conditions in real time and in a dynamic manner.

This study presents the design and implementation phases of a pedestrian – positioning field data... more This study presents the design and implementation phases of a pedestrian – positioning field data collection experiment by performing Post Process Kinematic positioning using highsensitivity GNSS receivers. The aim of this research is the investigation of the impact that various parameters, such as pedestrians’ characteristics, mobile phone use and walking pace may have on the characteristics of the pedestrian’s behaviour using low cost GNSS receiver data. Pedestrians’ characteristics include age, gender, body mass index, cellphone use. For this purpose, a controlled experiment was designed involving participants walking along a 220m track in a pedestrian area under different types of distraction (no distraction, hand-held conversation and texting) and different walking pace (normal-fast). The study sample size was 36 participants (20-73 years old), 15 male and 21 female who walked during the morning and afternoon hours. The equipment utilized involved a u-blox EVK-M8/NEO-M8T GNSS r...

The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2021

(paolo.dabove, vincenzo.dipietra)@polito.it

Remote Sensing, 2021

The availability of global navigation satellite systems (GNSS) on consumer devices has caused a d... more The availability of global navigation satellite systems (GNSS) on consumer devices has caused a dramatic change in every-day life and human behaviour globally. Although GNSS generally performs well outdoors, unavailability, intentional and unintentional threats, and reliability issues still remain. This has motivated the deployment of other complementary sensors in such a way that enables reliable positioning, even in GNSS-challenged environments. Besides sensor integration on a single platform to remedy the lack of GNSS, data sharing between platforms, such as in collaborative positioning, offers further performance improvements for positioning. An essential element of this approach is the availability of internode measurements, which brings in the strength of a geometric network. There are many sensors that can support ranging between platforms, such as LiDAR, camera, radar, and many RF technologies, including UWB, LoRA, 5G, etc. In this paper, to demonstrate the potential of the ...

The advantage for the development of a positioning solution for indoor parking facilities managem... more The advantage for the development of a positioning solution for indoor parking facilities management relates to the fixed geometric constraints imposed by man-made structures, the minimal weather influences and the low vehicle dynamics. Furthermore, easy access to commodities such as electrical supply and internet can facilitate further the use of alternative localization procedures. Notwithstanding, other factors, including the severe multipath conditions and the high attenuation and signal scattering effects, as well as the extended non-line-of-sight (NLoS) conditions make the positioning problem a difficult and case dependent task. This study offers a low-cost positioning solution to the problem relying primarily on the RFID Cell of Origin (CoO) technique resulting in to a discrete point vehicle trajectory. Then, Wi-Fi Receiver Signal Strength (RSS) observations act as a supplement to fill in the gaps and refine the final continuous vehicle trajectory. Also, this study introduces...

Dynamic displacement is a highly valuable information for the evaluation of bridge safety and per... more Dynamic displacement is a highly valuable information for the evaluation of bridge safety and performance, providing data on the dynamic behaviour of the structure under service loads. However, its measure is often challenging and costly: traditional techniques require a fixed support and a direct connection (or a clear line-of-sight) with the target point that is rarely present in large-scale infrastructures, making their deployment in long-term monitoring often not feasible. In this study, an indirect measuring approach deploying an electro-dynamic velocity sensor (geophone) and digital filtering is adopted to measure human-induced dynamic displacements on a lively footbridge. These sensors have an excellent cost to performance ratio, do not require any powering and, overall, are easy to install and deploy for a long time. Furthermore, geophones measure velocities and consequently only "one integration step" is needed to obtain displacements. The field test was performed with the bridge partially open to pedestrian passages, the geophone was placed in different positions directly on the deck, and a reference measure of the vertical displacement was obtained from a laser-based system placed nearby. Appropriate digital filtering is then applied on the geophone data before the integration. The calibration of digital filters and the validation of the results was carried out comparing the reconstructed vertical displacements from geophone data and the directly measured vertical displacements from the state-of-art measuring device. Under the assumption of pure dynamic loading, some promising results were obtained, reaching a tenth of a millimetre accuracy for the integrated signals.

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2020

The increasing demand for reliable indoor navigation systems is leading the research community to... more The increasing demand for reliable indoor navigation systems is leading the research community to investigate various approaches to obtain effective solutions usable with mobile devices. Among the recently proposed strategies, Ultra-Wide Band (UWB) positioning systems are worth to be mentioned because of their good performance in a wide range of operating conditions. However, such performance can be significantly degraded by large UWB range errors; mostly, due to non-line-of-sight (NLOS) measurements. This paper considers the integration of UWB with vision to support navigation and mapping applications. In particular, this work compares positioning results obtained with a simultaneous localization and mapping (SLAM) algorithm, exploiting a standard and a Time-of-Flight (ToF) camera, with those obtained with UWB, and then with the integration of UWB and vision. For the latter, a deep learning-based recognition approach was developed to detect UWB devices in camera frames. Such information is both introduced in the navigation algorithm and used to detect NLOS UWB measurements. The integration of this information allowed a 20% positioning error reduction in this case study.

International Association of Geodesy Symposia, 2020

Localization in GNSS-denied/challenged indoor/outdoor and transitional environments represents a ... more Localization in GNSS-denied/challenged indoor/outdoor and transitional environments represents a challenging research problem. As part of the joint IAG/FIG Working Groups 4.1.1 and 5.5 on Multi-sensor Systems, a benchmarking measurement campaign was conducted at The Ohio State University. Initial experiments have demonstrated that Cooperative Localization (CL) is extremely useful for positioning and navigation of platforms navigating in swarms or networks. In the data acquisition campaign, multiple sensor platforms, including vehicles, bicyclists and pedestrians were equipped with combinations of GNSS, Ultra-wide Band (UWB), Wireless Fidelity (Wi-Fi), Raspberry Pi units, cameras, Light Detection and Ranging (LiDAR) and inertial sensors for CL. Pedestrians wore a specially designed helmet equipped with some of these sensors. An overview of the experimental configurations, test scenarios, characteristics and sensor specifications is given. It has been demonstrated that all involved se...

Journal of Applied Geodesy, 2020

Localization in GNSS-denied/challenged indoor/outdoor and transitional environments represents a ... more Localization in GNSS-denied/challenged indoor/outdoor and transitional environments represents a challenging research problem. This paper reports about a sequence of extensive experiments, conducted at The Ohio State University (OSU) as part of the joint effort of the FIG/IAG WG on Multi-sensor Systems. Their overall aim is to assess the feasibility of achieving GNSS-like performance for ubiquitous positioning in terms of autonomous, global, preferably infrastructure-free positioning of portable platforms at affordable cost efficiency. In the data acquisition campaign, multiple sensor platforms, including vehicles, bicyclists and pedestrians were used whereby cooperative positioning (CP) is the major focus to achieve a joint navigation solution. The GPSVan of The Ohio State University was used as the main reference vehicle and for pedestrians, a specially designed helmet was developed. The employed/tested positioning techniques are based on using sensor data from GNSS, Ultra-wide Ba...

Sensors, 2019

Cooperative positioning (CP) utilises information sharing among multiple nodes to enable position... more Cooperative positioning (CP) utilises information sharing among multiple nodes to enable positioning in Global Navigation Satellite System (GNSS)-denied environments. This paper reports the performance of a CP system for pedestrians using Ultra-Wide Band (UWB) technology inGNSS-denied environments. This data set was collected as part of a benchmarking measurementcampaign carried out at the Ohio State University in October 2017. Pedestrians were equippedwith a variety of sensors, including two different UWB systems, on a specially designed helmetserving as a mobile multi-sensor platform for CP. Different users were walking in stop-and-go modealong trajectories with predefined checkpoints and under various challenging environments. Inthe developed CP network, both Peer-to-Infrastructure (P2I) and Peer-to-Peer (P2P) measurementsare used for positioning of the pedestrians. It is realised that the proposed system can achievedecimetre-level accuracies (on average, around 20 cm) in the com...

Applied Geomatics, 2019

In this paper, we address the challenge of robust indoor positioning using integrated UWB and Wi-... more In this paper, we address the challenge of robust indoor positioning using integrated UWB and Wi-Fi measurements. A key limitation of any fusion algorithm is whether the distribution that describes the random errors in the measurements has been correctly specified. Here, we describe the details of a set of practical experiments conducted on a purpose built calibration range, to evaluate the performance of commercial UWB sensors with Wi-Fi measurements as captured by an in-house smartphone application. In this paper, we present comparisons of ranges from the UWB sensors and the Wi-Fi built into the smartphone to true ranges obtained from a robotic total station. This approach is validated in both static and kinematic tests. The calibration range has been established as one component of an indoor laboratory to undertake a more diverse research agenda into robust indoor positioning systems. The experiments presented here have been conducted collaboratively under the joint FIG (WG5.5) and IAG (SC4.2) working groups on multi-sensor systems.

International Journal of Disaster Risk Reduction, 2017

Traffic simulation is a mature field, with several decades of development. While many mainstream ... more Traffic simulation is a mature field, with several decades of development. While many mainstream aspects can be assumed to be at a level where most challenges have been overcome, there are still edge cases that are not adequately covered. For example, traffic simulation of mixed networks in conditions close to exceeding capacity or in emergency cases is still a challenge. This research aims at developing a risk-reduction framework for largescale parking facilities and depots (for either passenger vehicles or commercial fleets) under constraints. An integrated methodological framework is therefore analyzed and then the emphasis is placed on the localization of vehicles under these conditions using a combination of state-of-the-art technologies. A case study is implemented to test the feasibility of the proposed technologies including smart-phone accelerometers, radio frequency identification technology, high-sensitivity GNSS receivers and Ultra-wideband technology. Then, an experiment was conducted in a large-scale parking facility, including vehicle positioning in indoor, outdoor and hybrid environments. This information is used as input for a simulation-based evacuation analysis of a large parking facility in Athens, Greece. The evaluation of four evacuation scenarios suggests that considerable risk reduction benefits can be obtained by suitable emergency response strategies.

IET Intelligent Transport Systems, 2017

Global Navigation Satellite Systems (GNSS) has become a kind of positioning standard due to the h... more Global Navigation Satellite Systems (GNSS) has become a kind of positioning standard due to the high penetration rate of this technology on mass market ITS applications. However, this positioning technique remains a real challenge for very demanding services. This paper reports on a practical and methodological approach for the evaluation of the GNSS positioning and attitude of vehicles in real life conditions. Test scenarios have been set up with several positioning sensors mounted on a vehicle for the collection of raw data on different road sections. The measurement of a high quality reference trajectory allowed to estimate position accuracy under different environmental conditions. We will show in detail the results and identify some typical situations where the quality of GNSS-only positioning is reduced and may impact the level of ITS services, e.g. road user charging or safety applications.

Journal of Applied Geodesy, 2016

This paper presents the dynamic testing of a roadway, single-span, cable-stayed bridge for a sequ... more This paper presents the dynamic testing of a roadway, single-span, cable-stayed bridge for a sequence of static load and ambient vibration monitoring scenarios. Deck movements were captured along both sideways of the bridge using a Digital Image Correlation (DIC) and a Ground-based Microwave Interfererometer (GBMI) system. Cable vibrations were measured at a single point location on each of the six cables using the GBMI technique.Dynamic testing involves three types of analyses; firstly, vibration analysis and modal parameter estimation (i. e., natural frequencies and modal shapes) of the deck using the combined DIC and GBMI measurements. Secondly, dynamic testing of the cables is performed through vibration analysis and experimental computation of their tension forces. Thirdly, the mechanism of cable-deck dynamic interaction is studied through their Power Spectra Density (PSD) and the Short Time Fourier Transform (STFT) analyses. Thereby, the global (deck and cable) and local (eith...

The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences

(paolo.dabove, vincenzo.dipietra)@polito.it

<p>The release of Android Raw GNSS Measurements API in mid-2016 has enabled the rec... more <p>The release of Android Raw GNSS Measurements API in mid-2016 has enabled the reconstruction of pseudorange, carrier-phase, Doppler and carrier-to-noise density (CN0) observables in low-cost, smart devices.  This technical development has opened the door to numerous applications that necessitate increased Position-Velocity-Time (PVT) quality metrics.  However, despite the recent advances in the field, deficiencies inherent to smartphones GNSS antenna and chipset, still account for excessive biases in the raw GNSS observables and for severe multipath effects in the satellite signal.  RAIM (Receiver Autonomous Integrity Monitoring) techniques is one way to monitor and increase the performance of the PVT solution of a GNSS receiver.  It is an augmentation method to detect and eventually reject anomalous (blunders or outliers) measurements and compute protection levels that bound position errors to preset limits.</p> <p>The implementation of RAIM technique to smartphone GNSS data is very limited and confined only to static positioning scenarios.  This study presents the results obtained from the testing of the classic RAIM technique in a series of kinematic positioning trials in urban environment using two cotemporary smartphone devices (i.e., Xiaomi Mi 8 and One Plus Nord2 5G).  In order to reconstruct a real use case, the smartphones were mounted on the vehicle dashboard.  The reference trajectory was obtained using a tactical grade GNSS/IMU system (NovAtel® PwrPak7, iMAR IMU-FSAS) fixed on the NTUA test vehicle roof-top sensor platform.  </p> <p>At a pre-processing stage the raw GNSS data have undergone through a Hatch filer.  This step allows to smooth iteratively the noisy code pseudorange measurements using the precise (but ambiguous) phase carrier measurements.  Data analysis includes two processing strategies. We employ the PANG-NAV open-source software released by LabPANG (PArthenope Navigation Group Laboratory) to compute the SPP (Single Point Positioning) solution in two ways.  We produce the standard and the RAIM-based SPP solution using different parameter setups.  The paper presents quantitative results and comparisons between the two smartphone-based solutions and the reference trajectory, and reveal the potential (benefits and limitations) of using the RAIM technique for smartphone positioning.</p>

<p>The recent advances in Information Technology (IT) and Micro-Electromechanical S... more <p>The recent advances in Information Technology (IT) and Micro-Electromechanical Systems (MEMS) technologies and their global adoption in contemporary smartphone and PDA devices enables the introduction of novel approaches for indoor positioning applications that combine multi-sensor capabilities.</p> <p>In this regard, Radio-frequency (RF), high accuracy ranging technologies operating in the Ultra-Wide Band (UWB) spectrum have recently been introduced in contemporary smartphone devices. Additionally, the adoption of Wi-Fi RTT technology in the most recent smartphone devices facilitates Peer-to-Infrastructure (P2I) medium level accuracy ranging in a widespread and seamless manner together with the standard web access functionality. Applications requiring absolute positioning of moderate to low accuracy may depend on Wi-Fi RTT-only systems, while high-accuracy UWB ranging would facilitate cases demanding safety-critical proximity reliant standards. Positioning architectures optimally utilizing these Two-Way Ranging (TWR) technologies may provide increased coverage and flexibility for indoor conditions in cases that a higher level of accuracy and availability is required.</p> <p>This study aims at utilizing RF-based range measurements and to combine them optimally into a Pedestrian to Infrastructure (P2I), as well as, Pedestrian to Pedestrian (P2P) collaborative functional model aided by inertial measurements for indoor positioning. The implementation of the proposed approach utilizes simulation-based TWR data from four infrastructure nodes to four roving nodes, whereas operational elements for each technology, such as sampling rate, data formatting and communications scheduling are taken into account.</p> <p>The distinct working scenarios examined in this study are as follows.  Firstly, we examine separately the performance of the two technological approaches (i.e., Wi-Fi RTT and UWB) for P2I positioning scenarios.  Secondly, we study the performance of the fuse the combined use of these technologies.  For this purpose, we employ a scenario featuring a mixture of Wi-Fi RTT anchor and UWB static rover ranges. Finally, the potential (benefits and limitations) of the inclusion of IMU-based Azimuth information in the KF computation is evaluated for all scenarios. The results obtained from this investigation indicate a potential improvement in position accuracy of the order of 29% and 37% for Wi-Fi RTT/ UWB and Wi-Fi RTT/ UWB/ IMU solutions accordingly.</p>

IEEE Open Journal of Intelligent Transportation Systems

This research is co-financed by Greece and the European Union (European Social Fund-ESF) through ... more This research is co-financed by Greece and the European Union (European Social Fund-ESF) through the Operational Programme Human Resources Development, Education and Lifelong Learning 2014-2020 in the context of the project "Advanced WiFi-RTT Based Localization Techniques for the Development and Testing of Pedestrian behavior Classification" (MIS 5049177).

Proceedings of conference GIS Ostrava 2021 Advances in Localization and Navigation, 2021

Minimizing fuel consumption while maximizing driving performance (i.e., less travel time, increas... more Minimizing fuel consumption while maximizing driving performance (i.e., less travel time, increased safety and less gas emissions) is a key factor for the successful implementation of any transport system. In this regard, monitoring driving behaviour and converting this information into real-time advice to drivers can benefit seriously the performance of transport and mobility services. This paper presents the design and implementation of a prototype system and a BI (Business Intelligence) model for fuel consumption optimization for heavy-duty vehicles. The system consists of an OBDH prototype, various external sensors (including GNSS/INS and environmental ones), and an on-purpose built FMS (Fleet Management System) bus logger. The paper revisits the concept of BI and attempts knowledge transfer from the field of data analytics for business information to a pure engineering problem. Preliminary analyses using real truck trajectory data reveals and quantifies the effect of driving behaviour on fuel consumption while it indicates the potential of the system to transform into an integrated, self-trained driver coaching system.

2021 7th International Conference on Models and Technologies for Intelligent Transportation Systems (MT-ITS), 2021

The volume of freight transport on roads has grown steadily over the years and is expected to inc... more The volume of freight transport on roads has grown steadily over the years and is expected to increase significantly over the next decade. Truck driver coaching systems have proved a key element in boosting efficiency, profitability and safety of the haulage sector whilst contributing to infrastructure asset management objectives. Notwithstanding new, commercial driver coaching systems have shown up recently in the market, still they operate as "black boxes", whilst their functionality and automation level is very limited. Given the enormous numbers of truck fleets currently operating worldwide, the necessity for an adaptable driver coaching system, capable of providing real-time functionality is evident. This study reports the design characteristics and first results from PEGASUS research project aiming at developing a self-trained, unified, driver-coaching system based on geolocation, IoT (Internet of Things) and BI (Business Intelligence) techniques. The system by design aims at reducing operational costs for the truck fleet, improving road safety, as well as contributing to green transportation. In effect, the system has been designed to produce user-friendly, two-way advice to lorry drivers tailored to the road conditions (e.g., geometry, road markings, neighboring vehicles) and operational (e.g., weather, traffic) conditions in real time and in a dynamic manner.

This study presents the design and implementation phases of a pedestrian – positioning field data... more This study presents the design and implementation phases of a pedestrian – positioning field data collection experiment by performing Post Process Kinematic positioning using highsensitivity GNSS receivers. The aim of this research is the investigation of the impact that various parameters, such as pedestrians’ characteristics, mobile phone use and walking pace may have on the characteristics of the pedestrian’s behaviour using low cost GNSS receiver data. Pedestrians’ characteristics include age, gender, body mass index, cellphone use. For this purpose, a controlled experiment was designed involving participants walking along a 220m track in a pedestrian area under different types of distraction (no distraction, hand-held conversation and texting) and different walking pace (normal-fast). The study sample size was 36 participants (20-73 years old), 15 male and 21 female who walked during the morning and afternoon hours. The equipment utilized involved a u-blox EVK-M8/NEO-M8T GNSS r...

The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2021

(paolo.dabove, vincenzo.dipietra)@polito.it

Remote Sensing, 2021

The availability of global navigation satellite systems (GNSS) on consumer devices has caused a d... more The availability of global navigation satellite systems (GNSS) on consumer devices has caused a dramatic change in every-day life and human behaviour globally. Although GNSS generally performs well outdoors, unavailability, intentional and unintentional threats, and reliability issues still remain. This has motivated the deployment of other complementary sensors in such a way that enables reliable positioning, even in GNSS-challenged environments. Besides sensor integration on a single platform to remedy the lack of GNSS, data sharing between platforms, such as in collaborative positioning, offers further performance improvements for positioning. An essential element of this approach is the availability of internode measurements, which brings in the strength of a geometric network. There are many sensors that can support ranging between platforms, such as LiDAR, camera, radar, and many RF technologies, including UWB, LoRA, 5G, etc. In this paper, to demonstrate the potential of the ...

The advantage for the development of a positioning solution for indoor parking facilities managem... more The advantage for the development of a positioning solution for indoor parking facilities management relates to the fixed geometric constraints imposed by man-made structures, the minimal weather influences and the low vehicle dynamics. Furthermore, easy access to commodities such as electrical supply and internet can facilitate further the use of alternative localization procedures. Notwithstanding, other factors, including the severe multipath conditions and the high attenuation and signal scattering effects, as well as the extended non-line-of-sight (NLoS) conditions make the positioning problem a difficult and case dependent task. This study offers a low-cost positioning solution to the problem relying primarily on the RFID Cell of Origin (CoO) technique resulting in to a discrete point vehicle trajectory. Then, Wi-Fi Receiver Signal Strength (RSS) observations act as a supplement to fill in the gaps and refine the final continuous vehicle trajectory. Also, this study introduces...

Dynamic displacement is a highly valuable information for the evaluation of bridge safety and per... more Dynamic displacement is a highly valuable information for the evaluation of bridge safety and performance, providing data on the dynamic behaviour of the structure under service loads. However, its measure is often challenging and costly: traditional techniques require a fixed support and a direct connection (or a clear line-of-sight) with the target point that is rarely present in large-scale infrastructures, making their deployment in long-term monitoring often not feasible. In this study, an indirect measuring approach deploying an electro-dynamic velocity sensor (geophone) and digital filtering is adopted to measure human-induced dynamic displacements on a lively footbridge. These sensors have an excellent cost to performance ratio, do not require any powering and, overall, are easy to install and deploy for a long time. Furthermore, geophones measure velocities and consequently only "one integration step" is needed to obtain displacements. The field test was performed with the bridge partially open to pedestrian passages, the geophone was placed in different positions directly on the deck, and a reference measure of the vertical displacement was obtained from a laser-based system placed nearby. Appropriate digital filtering is then applied on the geophone data before the integration. The calibration of digital filters and the validation of the results was carried out comparing the reconstructed vertical displacements from geophone data and the directly measured vertical displacements from the state-of-art measuring device. Under the assumption of pure dynamic loading, some promising results were obtained, reaching a tenth of a millimetre accuracy for the integrated signals.

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2020

The increasing demand for reliable indoor navigation systems is leading the research community to... more The increasing demand for reliable indoor navigation systems is leading the research community to investigate various approaches to obtain effective solutions usable with mobile devices. Among the recently proposed strategies, Ultra-Wide Band (UWB) positioning systems are worth to be mentioned because of their good performance in a wide range of operating conditions. However, such performance can be significantly degraded by large UWB range errors; mostly, due to non-line-of-sight (NLOS) measurements. This paper considers the integration of UWB with vision to support navigation and mapping applications. In particular, this work compares positioning results obtained with a simultaneous localization and mapping (SLAM) algorithm, exploiting a standard and a Time-of-Flight (ToF) camera, with those obtained with UWB, and then with the integration of UWB and vision. For the latter, a deep learning-based recognition approach was developed to detect UWB devices in camera frames. Such information is both introduced in the navigation algorithm and used to detect NLOS UWB measurements. The integration of this information allowed a 20% positioning error reduction in this case study.

International Association of Geodesy Symposia, 2020

Localization in GNSS-denied/challenged indoor/outdoor and transitional environments represents a ... more Localization in GNSS-denied/challenged indoor/outdoor and transitional environments represents a challenging research problem. As part of the joint IAG/FIG Working Groups 4.1.1 and 5.5 on Multi-sensor Systems, a benchmarking measurement campaign was conducted at The Ohio State University. Initial experiments have demonstrated that Cooperative Localization (CL) is extremely useful for positioning and navigation of platforms navigating in swarms or networks. In the data acquisition campaign, multiple sensor platforms, including vehicles, bicyclists and pedestrians were equipped with combinations of GNSS, Ultra-wide Band (UWB), Wireless Fidelity (Wi-Fi), Raspberry Pi units, cameras, Light Detection and Ranging (LiDAR) and inertial sensors for CL. Pedestrians wore a specially designed helmet equipped with some of these sensors. An overview of the experimental configurations, test scenarios, characteristics and sensor specifications is given. It has been demonstrated that all involved se...

Journal of Applied Geodesy, 2020

Localization in GNSS-denied/challenged indoor/outdoor and transitional environments represents a ... more Localization in GNSS-denied/challenged indoor/outdoor and transitional environments represents a challenging research problem. This paper reports about a sequence of extensive experiments, conducted at The Ohio State University (OSU) as part of the joint effort of the FIG/IAG WG on Multi-sensor Systems. Their overall aim is to assess the feasibility of achieving GNSS-like performance for ubiquitous positioning in terms of autonomous, global, preferably infrastructure-free positioning of portable platforms at affordable cost efficiency. In the data acquisition campaign, multiple sensor platforms, including vehicles, bicyclists and pedestrians were used whereby cooperative positioning (CP) is the major focus to achieve a joint navigation solution. The GPSVan of The Ohio State University was used as the main reference vehicle and for pedestrians, a specially designed helmet was developed. The employed/tested positioning techniques are based on using sensor data from GNSS, Ultra-wide Ba...

Sensors, 2019

Cooperative positioning (CP) utilises information sharing among multiple nodes to enable position... more Cooperative positioning (CP) utilises information sharing among multiple nodes to enable positioning in Global Navigation Satellite System (GNSS)-denied environments. This paper reports the performance of a CP system for pedestrians using Ultra-Wide Band (UWB) technology inGNSS-denied environments. This data set was collected as part of a benchmarking measurementcampaign carried out at the Ohio State University in October 2017. Pedestrians were equippedwith a variety of sensors, including two different UWB systems, on a specially designed helmetserving as a mobile multi-sensor platform for CP. Different users were walking in stop-and-go modealong trajectories with predefined checkpoints and under various challenging environments. Inthe developed CP network, both Peer-to-Infrastructure (P2I) and Peer-to-Peer (P2P) measurementsare used for positioning of the pedestrians. It is realised that the proposed system can achievedecimetre-level accuracies (on average, around 20 cm) in the com...

Applied Geomatics, 2019

In this paper, we address the challenge of robust indoor positioning using integrated UWB and Wi-... more In this paper, we address the challenge of robust indoor positioning using integrated UWB and Wi-Fi measurements. A key limitation of any fusion algorithm is whether the distribution that describes the random errors in the measurements has been correctly specified. Here, we describe the details of a set of practical experiments conducted on a purpose built calibration range, to evaluate the performance of commercial UWB sensors with Wi-Fi measurements as captured by an in-house smartphone application. In this paper, we present comparisons of ranges from the UWB sensors and the Wi-Fi built into the smartphone to true ranges obtained from a robotic total station. This approach is validated in both static and kinematic tests. The calibration range has been established as one component of an indoor laboratory to undertake a more diverse research agenda into robust indoor positioning systems. The experiments presented here have been conducted collaboratively under the joint FIG (WG5.5) and IAG (SC4.2) working groups on multi-sensor systems.

International Journal of Disaster Risk Reduction, 2017

Traffic simulation is a mature field, with several decades of development. While many mainstream ... more Traffic simulation is a mature field, with several decades of development. While many mainstream aspects can be assumed to be at a level where most challenges have been overcome, there are still edge cases that are not adequately covered. For example, traffic simulation of mixed networks in conditions close to exceeding capacity or in emergency cases is still a challenge. This research aims at developing a risk-reduction framework for largescale parking facilities and depots (for either passenger vehicles or commercial fleets) under constraints. An integrated methodological framework is therefore analyzed and then the emphasis is placed on the localization of vehicles under these conditions using a combination of state-of-the-art technologies. A case study is implemented to test the feasibility of the proposed technologies including smart-phone accelerometers, radio frequency identification technology, high-sensitivity GNSS receivers and Ultra-wideband technology. Then, an experiment was conducted in a large-scale parking facility, including vehicle positioning in indoor, outdoor and hybrid environments. This information is used as input for a simulation-based evacuation analysis of a large parking facility in Athens, Greece. The evaluation of four evacuation scenarios suggests that considerable risk reduction benefits can be obtained by suitable emergency response strategies.

IET Intelligent Transport Systems, 2017

Global Navigation Satellite Systems (GNSS) has become a kind of positioning standard due to the h... more Global Navigation Satellite Systems (GNSS) has become a kind of positioning standard due to the high penetration rate of this technology on mass market ITS applications. However, this positioning technique remains a real challenge for very demanding services. This paper reports on a practical and methodological approach for the evaluation of the GNSS positioning and attitude of vehicles in real life conditions. Test scenarios have been set up with several positioning sensors mounted on a vehicle for the collection of raw data on different road sections. The measurement of a high quality reference trajectory allowed to estimate position accuracy under different environmental conditions. We will show in detail the results and identify some typical situations where the quality of GNSS-only positioning is reduced and may impact the level of ITS services, e.g. road user charging or safety applications.

Journal of Applied Geodesy, 2016

This paper presents the dynamic testing of a roadway, single-span, cable-stayed bridge for a sequ... more This paper presents the dynamic testing of a roadway, single-span, cable-stayed bridge for a sequence of static load and ambient vibration monitoring scenarios. Deck movements were captured along both sideways of the bridge using a Digital Image Correlation (DIC) and a Ground-based Microwave Interfererometer (GBMI) system. Cable vibrations were measured at a single point location on each of the six cables using the GBMI technique.Dynamic testing involves three types of analyses; firstly, vibration analysis and modal parameter estimation (i. e., natural frequencies and modal shapes) of the deck using the combined DIC and GBMI measurements. Secondly, dynamic testing of the cables is performed through vibration analysis and experimental computation of their tension forces. Thirdly, the mechanism of cable-deck dynamic interaction is studied through their Power Spectra Density (PSD) and the Short Time Fourier Transform (STFT) analyses. Thereby, the global (deck and cable) and local (eith...