28 research outputs found
Estimation And Tracking Algorithm For Autonomous Vehicles And Humans
Autonomous driving systems have experienced impressive growth in recent years. The present research community is working on several challenging aspects, such as, tracking, localization, path planning and control. In this thesis, first, we focus on tracking system and present a method to accurately track a moving vehicle. In the vehicle tracking, considering the proximity of surrounding vehicles, it is critical to detect their unusual maneuvers as quickly as possible, especially when autonomous vehicles operate among human-operated traffic. In this work, we present an approach to quickly detect lane-changing maneuvers of the nearby vehicles. The proposed algorithm is based on the optimal likelihood ratio test, known as Page test. Second, we consider another form of tracking: tracking the movements of humans in indoor settings. Indoor localization of staff and patients based on radio frequency identification (RFID) technology has promising potential application in the healthcare sector. The use of an active RFID in real-time indoor positioning system without any sacrifice of localization accuracy is intended to provide security, guidance and support service to patients. In this paper maximum likelihood estimation along with its Cramer-Rao lower bound of the locations of active RFID tags are presented by exploring the received signal strength indicator which is collected at the readers. The performance of real-time localization system is implemented by using an extended Kalman filter (EKF)
Indoor localisation by using wireless sensor nodes
This study is devoted to investigating and developing WSN based localisation approaches with high position accuracies indoors. The study initially summarises the design and implementation of localisation systems and WSN architecture together with the characteristics of LQI and RSSI values.
A fingerprint localisation approach is utilised for indoor positioning applications. A k-nearest neighbourhood algorithm (k-NN) is deployed, using Euclidean distances between the fingerprint database and the object fingerprints, to estimate unknown object positions. Weighted LQI and RSSI values are calculated and the k-NN algorithm with different weights is utilised to improve the position detection accuracy. Different weight functions are investigated with the fingerprint localisation technique. A novel weight function which produced the maximum position accuracy is determined and employed in calculations.
The study covered designing and developing the centroid localisation (CL) and weighted centroid localisation (WCL) approaches by using LQI values. A reference node localisation approach is proposed. A star topology of reference nodes are to be utilized and a 3-NN algorithm is employed to determine the nearest reference nodes to the object location. The closest reference nodes are employed to each nearest reference nodes and the object locations are calculated by using the differences between the closest and nearest reference nodes.
A neighbourhood weighted localisation approach is proposed between the nearest reference nodes in star topology. Weights between nearest reference nodes are calculated by using Euclidean and physical distances. The physical distances between the object and the nearest reference nodes are calculated and the trigonometric techniques are employed to derive the object coordinates.
An environmentally adaptive centroid localisation approach is proposed.Weighted standard deviation (STD) techniques are employed adaptively to estimate the unknown object positions. WSNs with minimum RSSI mean values are considered as reference nodes across the sensing area. The object localisation is carried out in two phases with respect to these reference nodes. Calculated object coordinates are later translated into the universal coordinate system to determine the actual object coordinates.
Virtual fingerprint localisation technique is introduced to determine the object locations by using virtual fingerprint database. A physical fingerprint database is organised in the form of virtual database by using LQI distribution functions. Virtual database elements are generated among the physical database elements with linear and exponential distribution functions between the fingerprint points. Localisation procedures are repeated with virtual database and localisation accuracies are improved compared to the basic fingerprint approach.
In order to reduce the computation time and effort, segmentation of the sensing area is introduced. Static and dynamic segmentation techniques are deployed. Segments are defined by RSS ranges and the unknown object is localised in one of these segments. Fingerprint techniques are applied only in the relevant segment to find the object location.
Finally, graphical user interfaces (GUI) are utilised with application program interfaces (API), in all calculations to visualise unknown object locations indoors
Neighborhood Localization Method for Locating Construction Resources Based on RFID and BIM
Construction sites are changing every day, which brings some difficulties for different contractors to do their tasks properly. One of the key points for all entities who work on the same site is the location of resources including materials, tools, and equipment. Therefore, the lack of an integrated localization system leads to increase the time wasted on searching for resources. In this research, a localization method which does not need infrastructure is proposed to overcome this problem. Radio Frequency Identification (RFID) as a localization technology is integrated with Building Information Modeling (BIM) as a method of creating, sharing, exchanging and managing the building information throughout the lifecycle among all stakeholders. In the first stage, a requirements’ gathering and conceptual design are performed to add new entities, data types, and properties to the BIM, and relationships between RFID tags and building assets are identified. Secondly, it is proposed to distribute fixed tags with known positions as reference tags for the RFID localization approach. Then, a clustering method chooses the appropriate reference tags to provide them to an Artificial Neural Network (ANN) for further computations. Additionally, Virtual Reference Tags (VRTs) are added to the system to increase the resolution of localization while limiting the cost of the system deployment. Finally, different case studies and simulations are implemented and tested to explore the technical feasibility of the proposed approach
Wireless Positioning and Tracking for Internet of Things in GPS-denied Environments
Wireless positioning and tracking have long been a critical technology for various applications such as indoor/outdoor navigation, surveillance, tracking of assets and employees, and guided tours, among others. Proliferation of Internet of Things (IoT) devices, the evolution of smart cities, and vulnerabilities of traditional localization technologies to cyber-attacks such as jamming and spoofing of GPS necessitate development of novel radio frequency (RF) localization and tracking technologies that are accurate, energy-efficient, robust, scalable, non-invasive and secure. The main challenges that are considered in this research work are obtaining fundamental limits of localization accuracy using received signal strength (RSS) information with directional antennas, and use of burst and intermittent measurements for localization. In this dissertation, we consider various RSS-based techniques that rely on existing wireless infrastructures to obtain location information of corresponding IoT devices. In the first approach, we present a detailed study on localization accuracy of UHF RF IDentification (RFID) systems considering realistic radiation pattern of directional antennas. Radiation patterns of antennas and antenna arrays may significantly affect RSS in wireless networks. The sensitivity of tag antennas and receiver antennas play a crucial role. In this research, we obtain the fundamental limits of localization accuracy considering radiation patterns and sensitivity of the antennas by deriving Cramer-Rao Lower Bounds (CRLBs) using estimation theory techniques. In the second approach, we consider a millimeter Wave (mmWave) system with linear antenna array using beamforming radiation patterns to localize user equipment in an indoor environment. In the third approach, we introduce a tracking and occupancy monitoring system that uses ambient, bursty, and intermittent WiFi probe requests radiated from mobile devices. Burst and intermittent signals are prominent characteristics of IoT devices; using these features, we propose a tracking technique that uses interacting multiple models (IMM) with Kalman filtering. Finally, we tackle the problem of indoor UAV navigation to a wireless source using its Rayleigh fading RSS measurements. We propose a UAV navigation technique based on Q-learning that is a model-free reinforcement learning technique to tackle the variation in the RSS caused by Rayleigh fading
When learning meets RFIDs: The case of activity identification
Over the past decades have seen booming interests in human activity identification that is widely used in a range of Internet-of-Things applications, such as healthcare and smart homes. It has attracted significant attention from both academia and industry, with a wide range of solutions based on cameras, radars, and/or various inertial sensors. They generally require the object of identification to carry sensors/wireless transceivers, which are not negligible in both size and weight, not to mention the constraints from the battery. Radio frequency identification (RFID) is a promising technology that can overcome those difficulties due to its low cost, small form size, and batterylessness, making it widely used in a range of mobile applications. The information offered by today\u27s RFID tags however are quite limited, and the typical raw data (RSSI and phase angles) are not necessarily good indicators of human activities (being either insensitive or unreliable as revealed by our realworld experiments). As such, existing RFID-based activity identification solutions are far from being satisfactory. It is also well known that the accuracy of the readings can be noticeably affected by multipath, which unfortunately is inevitable in an indoor environment and is complicated with multiple reference tags. In this thesis, we first reviewed the literature and research challenges of multipath effects in activity identification with RFIDs. Then we introduced three advanced RFID learning-based activity identification frameworks, i.e., i2tag, TagFree and M2AI, for tag mobility profiling, RFID-based device-free activity identification and tag-attached multi-object activity identification, respectively. Our extensive experiments further demonstrate their superiority on activity identification in the multipath-rich environments
Indoor Positioning and Navigation
In recent years, rapid development in robotics, mobile, and communication technologies has encouraged many studies in the field of localization and navigation in indoor environments. An accurate localization system that can operate in an indoor environment has considerable practical value, because it can be built into autonomous mobile systems or a personal navigation system on a smartphone for guiding people through airports, shopping malls, museums and other public institutions, etc. Such a system would be particularly useful for blind people. Modern smartphones are equipped with numerous sensors (such as inertial sensors, cameras, and barometers) and communication modules (such as WiFi, Bluetooth, NFC, LTE/5G, and UWB capabilities), which enable the implementation of various localization algorithms, namely, visual localization, inertial navigation system, and radio localization. For the mapping of indoor environments and localization of autonomous mobile sysems, LIDAR sensors are also frequently used in addition to smartphone sensors. Visual localization and inertial navigation systems are sensitive to external disturbances; therefore, sensor fusion approaches can be used for the implementation of robust localization algorithms. These have to be optimized in order to be computationally efficient, which is essential for real-time processing and low energy consumption on a smartphone or robot
Train Localisation using Wireless Sensor Networks
Safety and reliability have always been concerns for railway transportation.
Knowing the exact location of a train enables the railway system to react to
an unusual situation for the safety of human lives and properties. Generally,
the accuracy of localisation systems is related with their deployment and
maintenance costs, which can be on the order of millions of dollars a year.
Despite a lot of research efforts, existing localisation systems based on different
technologies are still limited because most of them either require
expensive infrastructure (ultrasound and laser), have high database maintenance,
computational costs or accumulate errors (vision), offer limited
coverage (GPS-dark regions, Wi-Fi, RFID) or provide low accuracy (audible
sound). On the other hand, wireless sensor networks (WSNs) offer the
potential for a cheap, reliable and accurate solutions for the train localisation
system. This thesis proposes a WSN-based train localisation system,
in which train location is estimated based on the information gathered
through the communication between the anchor sensors deployed along the
track and the gateway sensor installed on the train, such as anchor sensors'
geographic coordinates and the Received Signal Strength Indicator (RSSI).
In the proposed system, timely anchor-gateway communication implies accurate
localisation. How to guarantee effective communication between anchor sensors along the track and the gateway sensor on the train is a challenging problem for WSN-based train localisation. I propose a beacon driven sensors wake-up scheme (BWS) to address this problem. BWS allows each anchor sensor to run an asynchronous duty-cycling protocol to conserve energy and establishes an upper bound on the sleep time in one duty
cycle to guarantee their timely wake-up once a train approaches. Simulation
results show that the BWS scheme can timely wake up the anchor
sensors at a very low energy consumption cost.
To design an accurate scheme for train localisation, I conducted on-site
experiments in an open field, a railway station and a tunnel, and the results show that RSSI can be used as an estimator for train localisation and
its applicability increases with the incorporation of another type of data
such as location information of anchor sensors. By combining the advantages
of RSSI-based distance estimation and Particle Filtering techniques,
I designed a Particle-Filter-based train localisation scheme and propose
a novel Weighted RSSI Likelihood Function (WRLF) for particle update.
The proposed localisation scheme is evaluated through extensive simulations
using the data obtained from the on-site measurements. Simulation
results demonstrate that the proposed scheme can achieve significant accuracy,
where average localisation error stays under 30 cm at the train speed
of 40 m=s, 40% anchor sensors failure rate and sparse deployment. In addition,
the proposed train localisation scheme is robust to changes in train
speed, the deployment density and reliability of anchor sensors.
Anchor sensors are prone to hardware and software deterioration such as
battery outage and dislocation. Therefore, in order to reduce the negative
impacts of these problems, I designed a novel Consensus-based Anchor sensor
Management Scheme (CAMS), in which each anchor sensor performs
a self-diagnostics and reports the detected faults in the neighbourhood.
CAMS can assist the gateway sensor to exclude the input from the faulty
anchor sensors. In CAMS, anchor sensors update each other about their
opinions on other neighbours and develops consensus to mark faulty sensors.
In addition, CAMS also reports the system information such as signal
path loss ratio and allows anchor sensors to re-calibrate and verify their
geographic coordinates. CAMS is evaluated through extensive simulations
based on real data collected from field experiments. This evaluation also
incorporated the simulated node failure model in simulations.
Though there are no existing WSN-based train localisation systems available
to directly compare our results with, the proposed schemes are evaluated
with real datasets, theoretical models and existing work wherever it
was possible. Overall, the WSN-based train localisation system enables the
use of RSSI, with combination of location coordinates of anchor sensors, as
location estimator. Due to low cost of sensor devices, the cost of overall
system remains low. Further, with duty-cycling operation, energy of the
sensor nodes and system is conserved
Sensor Fusion for Location Estimation Technologies
Location estimation performance is not always satisfactory and improving it
can be expensive. The performance of location estimation technology can be
increased by refining the existing location estimation technologies. A better
way of increasing performance is to use multiple technologies and combine
the available data provided by them in order to obtain better results. Also,
maintaining one's location privacy while using location estimation technology is a challenge. How can this problem be solved?
In order to make it easier to perform sensor fusion on the available
data and to speed up development, a
flexible framework centered around
a component-based architecture was designed. In order to test the performance of location estimation using the proposed sensor fusion framework,
the framework and all the necessary components were implemented and
tested. In order to solve the location estimation privacy issues, a comprehensive design that considers all aspects of the problem, from the physical
aspects of using radio transmissions to communicating and using location
data, is proposed.
The experimental results of testing the location estimation sensor fusion
framework show that by using sensor fusion, the availability of location estimation is always increased and the accuracy is always increased on average.
The experimental results also allow the profiling of the sensor fusion framework's time and energy consumption. In the case of time consumption, there
is a 0.32% - 17.06% - 5.05% - 77.58% split between results overhead, engine
overhead, component communication time and component execution time
on an average. The more measurements are gathered by the data gathering
components, the more the component execution time increases relative to
all the other execution times because component execution time is the only
one that increases while the others remain constant
Smart campuses : extensive review of the last decade of research and current challenges
Novel intelligent systems to assist energy transition and improve sustainability can be deployed at different scales, ranging from a house to an entire region. University campuses are an interesting intermediate size (big enough to matter and small enough to be tractable) for research, development, test and training on the integration of smartness at all levels, which has led to the emergence of the concept of “smart campus” over the last few years. This review article proposes an extensive analysis of the scientific literature on smart campuses from the last decade (2010-2020). The 182 selected publications are distributed into seven categories of smartness: smart building, smart environment, smart mobility, smart living, smart people, smart governance and smart data. The main open questions and challenges regarding smart campuses are presented at the end of the review and deal with sustainability and energy transition, acceptability and ethics, learning models, open data policies and interoperability. The present work was carried out within the framework of the Energy Network of the Regional Leaders Summit (RLS-Energy) as part of its multilateral research efforts on smart region