Wireless Positioning System Research Articles

Implementation of a Highly Mobile UAVs Direction Finding Complex Using Virtual Magnetic Dipoles

Relevance. In the context of the development of modern broadband communication systems, the task of performing direction finding of signals using highly mobile direction finding systems (UAVs) is becoming especially urgent. They impose restrictions on the size of antenna elements and the distance between them, which leads to an increase in the mathematical error of the bearing. Problem statement. The paper sets the task of considering the possibility of increasing the direction finding accuracy of a highly mobile complex by using virtual magnetic dipole technology. A feature of this method is the minimization of distortions introduced by the carrier body into the characteristics of the measured field. To measure the field characteristics, as well as their partial components, vector antenna elements were used. Goal of the work is to study the characteristics of a radio direction finding complex using virtual magnetic dipole methods in conditions of distortions introduced by the carrier body. As an example, cases of direction finding of differently polarized waves, taking into account the influence of radomes of antenna elements, assessment of the maximum resolution accuracy, as well as noise stability are considered. The finite element method implemented in DS CST Studio Suite 2024 was used in the modeling. Result. During the research, a plane wave with different bearings fell on a UAV with a direction finding complex, which made it possible to carry out the most accurate research. The results of the work also include the creation of a model of a radio direction finding complex, which can be installed on a small UAV, providing high accuracy of wave direction finding in passive mode.The novelty of the method used lies in the application of methods for the formation of virtual magnetic dipoles based on the measured characteristics of the distorted electric field. New to this work are modeling cases that are associated with noise suppression, the influence of antenna element housings, as well as assessment of the maximum resolution accuracy.Practical significance of the work lies in the creation of a model of a radio location system based on vector antenna elements, which are used to measure the characteristics of the electromagnetic field with subsequent direction finding based on the magnetic field.

Application of density clustering with noise combined with particle swarm optimization in UWB indoor positioning

Due to the presence of non-line-of-sight (NLOS) obstacles, the localization accuracy in ultra-wideband (UWB) wireless indoor localization systems is typically substantially lower. To minimize the influence of these environmental factors and improve the accuracy of indoor wireless positioning, this paper proposes a density clustering with noise combined with particle swarm optimization (DCNPSO) to improve UWB positioning. Which exploits the advantages of the density-based spatial clustering algorithm with noise (DBSCAN) and particle swarm optimization (PSO) algorithm. The experimental results show that the DCNPSO algorithm achieves 45.25% and 36.14% higher average positioning accuracy than the DBSCAN and PSO algorithms, respectively. The positioning error of this algorithm remains stable within 3 cm in static positioning and can achieve high accuracy in NLOS environments.

Simulation-based evaluation of indoor positioning systems in connected aircraft cabins

With regard to the demanding aircraft cabin environment, this paper delves into the rising use of location-aware radio communication systems to streamline operational processes. We propose a hybrid deterministic and stochastic simulation approach, incorporating model-based ray-tracing and empirical residual simulation. The methodology presented allows for the evaluation of localization methods based on geometric relations, serving as both a data generation and validation tool. We elaborate how different radio properties and propagation phenomena influence these geometric relations and the localization process. This paper includes a publicly available dataset derived from the simulation approach, facilitating transparency and further analysis in the field of aircraft cabin radio localization systems.

A CFO-Assisted Algorithm for Wireless Time-Difference-of-Arrival Localization Networks: Analytical Study and Experimental Results

Localization of wireless transmitters is traditionally done using Radio Frequency (RF) sensors that measure the propagation delays between the transmitter and a set of anchor receivers. One of the major challenges of wireless localization systems is the need for anchor nodes to be time-synchronized to achieve accurate localization of a target node. Using a reference transmitter is an efficient way to synchronize the anchor nodes Over-The-Air (OTA), but such algorithms require multiple periodic messages to achieve tight synchronization. In this paper, we propose a new synchronization method that only requires a single message from a reference transmitter. The main idea is to use the Carrier Frequency Offset (CFO) from the reference node, alongside the Time of Arrival (ToA) of the reference node messages, to achieve tight synchronization. The ToA allows the anchor nodes to compensate for their absolute time offset, and the CFO allows the anchor nodes to compensate for their local oscillator drift. Additionally, using the CFO of the messages sent by the reference nodes and the target nodes also allow us to estimate the speed of the targets. The error of the proposed algorithm is derived analytically and is validated through controlled laboratory experiments. Finally, the algorithm is validated by realistic outdoor vehicular measurements with a software-defined radio testbed.

Efficient Detection of Cooperative External Attacks in Wireless Localization Systems

Efficient Detection of Cooperative External Attacks in Wireless Localization Systems

Cyber-WISE: A Cyber-Physical Deep Wireless Indoor Positioning System and Digital Twin Approach.

In recent decades, there have been significant research efforts focusing on wireless indoor localization systems, with fingerprinting techniques based on received signal strength leading the way. The majority of the suggested approaches require challenging and laborious Wi-Fi site surveys to construct a radio map, which is then utilized to match radio signatures with particular locations. In this paper, a novel next-generation cyber-physical wireless indoor positioning system is presented that addresses the challenges of fingerprinting techniques associated with data collection. The proposed approach not only facilitates an interactive digital representation that fosters informed decision-making through a digital twin interface but also ensures adaptability to new scenarios, scalability, and suitability for large environments and evolving conditions during the process of constructing the radio map. Additionally, it reduces the labor cost and laborious data collection process while helping to increase the efficiency of fingerprint-based positioning methods through accurate ground-truth data collection. This is also convenient for working in remote environments to improve human safety in locations where human access is limited or hazardous and to address issues related to radio map obsolescence. The feasibility of the cyber-physical system design is successfully verified and evaluated with real-world experiments in which a ground robot is utilized to obtain a radio map autonomously in real-time in a challenging environment through an informed decision process. With the proposed setup, the results demonstrate the success of RSSI-based indoor positioning using deep learning models, including MLP, LSTM Model 1, and LSTM Model 2, achieving an average localization error of ≤2.16 m in individual areas. Specifically, LSTM Model 2 achieves an average localization error as low as 1.55 m and 1.97 m with 83.33% and 81.05% of the errors within 2 m for individual and combined areas, respectively. These outcomes demonstrate that the proposed cyber-physical wireless indoor positioning approach, which is based on the application of dynamic Wi-Fi RSS surveying through human feedback using autonomous mobile robots, effectively leverages the precision of deep learning models, resulting in localization performance comparable to the literature. Furthermore, they highlight its potential for suitability for deployment in real-world scenarios and practical applicability.

When Wireless Localization Meets Artificial Intelligence: Basics, Challenges, Synergies, and Prospects

The rapid development of information communication and artificial intelligence (AI) technology is driving innovation in various new application fields such as autonomous driving, augmented reality, and the metaverse. In particular, the advancement of wireless localization technology plays a great role in these cutting-edge technologies. However, traditional wireless localization systems rely on the global navigation satellite system (GNSS), which is ineffective in indoor or underground environments. To overcome this issue, indoor positioning systems (IPS) have gained attention, and various localization techniques utilizing wireless communication were studied. Subsequently, AI technologies are improving the performance of wireless localization and addressing problems that were previously difficult to solve. In this paper, we summarize wireless localization techniques and define the factors that impede their performance. Furthermore, we categorize AI algorithms and present examples of how they can be used to address these hindering factors. Finally, we propose open research directions and prospects for AI-assisted wireless localization.

A Fully Wireless and Batteryless Localization System with 50 Micrometre Motion Detection Capability and Adaptive Transmitter Power Control for Point-of-Care Biomedical Applications.

Localization has varied applications in biomedicine, such as wireless capsule endoscopy (WCE), detection of cancerous tissue, drug delivery, robotic surgeries, and brain mapping. Currently, most localization systems are battery-powered and suffer from issues regarding battery leakage and limited battery life, resulting in potential health hazards and inconveniences when using them for continuous health monitoring applications. This paper proposes an entirely wireless and battery-less 2D localization system consisting of an integrated circuit (IC) that is wirelessly powered at a distance of 4 cm by a 40.68 MHz radio frequency (RF) power of only 2 W. The proposed localization system wirelessly transmits a locked sub-harmonic 13.56 MHz signal generated from the wirelessly received 40.68 MHz RF power signal, eliminating the need for a power-hungry oscillator. Additionally, the system, having a measurement latency of 11.3 ms, has also been verified to sense motion as small as 50 μm as well as measure the rate of motion up to 10 beats per minute, therefore extending its application to the detection of physiological motions such as diaphragm motion during breathing. The localizer has a small form factor of 17 mm × 12 mm × 0.2 mm and consumes an average power of 6 μW. Ex vivo measurements using the localizer inside the porcine intestine demonstrate a localization accuracy of less than 5 mm.

Software Methodology for Data Control and Collection for Autonomous Monitoring Systems with a Large Amount of Generated Information on the Example of Software for a Hydrological Radiolocation System

Introduction . The current data monitoring and collection systems produce a growing amount of generated information. Such factors, as the increasing sampling rate of ADCs and the increasing speed of systems for primary processing, receiving, and transmitting information, etc., make the systems operate almost at the bandwidth limit of data transmission interfaces. In some applications, such a flow is redundant and can be optimized through the use of various algorithms for the primary processing of information. However, in some applications, reducing the data flow is impossible, since the received information is processed with a delay. Therefore, the development of a software methodology for controlling and collecting data in the system of automatic monitoring of the sea surface by a hydrological radiolocation system seems a relevant research task. Aim . To synthesize a methodology and to develop software for controlling the information system of radar monitoring of the sea surface. Materials and methods . System approach, software architectural and algorithmic design, software quality management methods, system analysis, Qt framework, C++ programming language. Results . A working methodology for designing software for controlling information and measurement technologies with a large amount of generated data was obtained. The effectiveness of the methodology and software quality were confirmed by control tests. A 3-month autonomous testing of the stability and reliability of the system was carried out. Detection of data loss in the system comprised less than 0.002 %, thus not exceeding the specified critical level of 0.5 %. Conclusion . The developed methodology can be used in designing software for controlling information and measuring systems generating a large amount of data. The approaches used to build a multithread software architecture with asynchronous data flow control has shown their high efficiency.

A Survey of the Performance-Limiting Factors of a 2-Dimensional RSS Fingerprinting-Based Indoor Wireless Localization System

A receive signal strength (RSS) fingerprinting-based indoor wireless localization system (I-WLS) uses a localization machine learning (ML) algorithm to estimate the location of an indoor user using RSS measurements as the position-dependent signal parameter (PDSP). There are two stages in the system's localization process: the offline phase and the online phase. The offline phase starts with the collection and generation of RSS measurement vectors from radio frequency (RF) signals received at fixed reference locations, followed by the construction of an RSS radio map. In the online phase, the instantaneous location of an indoor user is found by searching the RSS-based radio map for a reference location whose RSS measurement vector corresponds to the user's instantaneously acquired RSS measurements. The performance of the system depends on a number of factors that are present in both the online and offline stages of the localization process. This survey identifies these factors and examines how they impact the overall performance of the 2-dimensional (2-D) RSS fingerprinting-based I-WLS. The effects of these factors are discussed, as well as previous researchers' suggestions for minimizing or mitigating them and future research trends in RSS fingerprinting-based I-WLS.

A Review of Wireless Positioning Techniques and Technologies: From Smart Sensors to 6G

In recent years, tremendous advances have been made in the design and applications of wireless networks and embedded sensors. The combination of sophisticated sensors with wireless communication has introduced new applications, which can simplify humans’ daily activities, increase independence, and improve quality of life. Although numerous positioning techniques and wireless technologies have been introduced over the last few decades, there is still a need for improvements, in terms of efficiency, accuracy, and performance for the various applications. Localization importance increased even more recently, due to the coronavirus pandemic, which made people spend more time indoors. Improvements can be achieved by integrating sensor fusion and combining various wireless technologies for taking advantage of their individual strengths. Integrated sensing is also envisaged in the coming technologies, such as 6G. The primary aim of this review article is to discuss and evaluate the different wireless positioning techniques and technologies available for both indoor and outdoor localization. This, in combination with the analysis of the various discussed methods, including active and passive positioning, SLAM, PDR, integrated sensing, and sensor fusion, will pave the way for designing the future wireless positioning systems.

A Self-Calibrating Localization Solution for Sport Applications with UWB Technology

This study addressed the problem of localization in an ultrawide-band (UWB) network, where the positions of both the access points and the tags needed to be estimated. We considered a fully wireless UWB localization system, comprising both software and hardware, featuring easy plug-and-play usability for the consumer, primarily targeting sport and leisure applications. Anchor self-localization was addressed by two-way ranging, also embedding a Gauss-Newton algorithm for the estimation and compensation of antenna delays, and a modified isolation forest algorithm working with low-dimensional set of measurements for outlier identification and removal. This approach avoids time-consuming calibration procedures, and it enables accurate tag localization by the multilateration of time difference of arrival measurements. For the assessment of performance and the comparison of different algorithms, we considered an experimental campaign with data gathered by a proprietary UWB localization system.

A Non-Line-of-Sight Wireless Indoor Localization System Using Custom-Designed Radio Relay and Uniform Circular Array

Indoor localization using WiFi signals, though getting studied for many years, is not adopted extensively in real indoor environments yet. One possible impediment is that many prior systems perform worse in non-line-of-sight (NLoS) indoor scenarios than in line-of-sight (LoS) scenarios or even fail to work. Nevertheless, realizing localization in both LoS and NLoS scenarios is indispensable for a viable system working in indoor environments. Since existing state-of-the-art solutions mainly aim to localize a target in LoS indoor scenarios, we present a system that uses multipath channel parameters to achieve localization with a single AP in indoor NLoS scenarios. The proposed introduces deployable and simple custom-designed radio relays to assist localization, which can receive signals from the target and forward them to the AP in NLoS scenarios. Field trials conducted in a real NLoS scenario show that our system achieves a median 3-D localization accuracy of 86 cm with a uniform circular array (UCA) in most NLoS conditions, i.e., the direct path from a target to AP is not completely blocked. More importantly, even if in a challenging NLoS condition, i.e., the direct path does not exist, our system can still achieve a median 2-D localization accuracy of 85 cm.

CHARACTERISTICS OF THE IMPLICATIONS OF m-ROZPODL NAKAGAM

Detection of a correlation signal against the background of noise (occurence) is an important task of primary information processing in modern radio engineering systems of information transmission, control, navigation, radio monitoring and radiolocation. The reception of radio signals is accompanied by many accidental factors, which lead to the fact that the additive mixture very often has a non-causal distribution. For this reason, the methods of the theory of probability and mathematical statistics are used for the acceptance and processing of the accepted signal, and the acceptance and detection is regarded as a mathematical problem.
 Receiving capabilities of radio engineering systems are largely determined by the detection characteristics, which, in turn, depend on the tightness with the received signal. In order to ensure the compliance, it is necessary to know the law of distribution of the intensity and probability of the output effect of the receiver. The knowledge of the distribution of the probability of frequency determines the characteristics of the detection of the receiver of radio engineering systems and provides a wide range of functional possibilities in the execution of statistical tasks in the primary processing of information.
 Analytical expressions that determine the probability of correct detection through the probability of the hibnothreshold signal/noise ratio at the receiver output for coherent signals with a uniform initial phase and a nakagami-like amplitude are presented.
 On the basis of the obtained analytical expressions a family of curves was created for signal models, where fluctuations are very small or absent in general and which are adequately described by Nakagami’s law of dispersion.

Precision Enhancement of Wireless Localization System Using Passive DOA Multiple Sensor Network for Moving Target.

Determining the direction-of-arrival (DOA) of any signal of interest has long been of great interest to the wireless localization research community for military and civilian applications. To efficiently facilitate the deployment of DOA systems, the accuracy of wireless localization is critical. Hence, this paper proposes a novel method to improve the prediction result of a wireless DOA localization system. By considering the signal variation existing in the complex environment, the actual location of the target can be determined including the maximum prediction error. Moreover, the scenario of the moving target is further investigated by incorporating the adaptive Kalman Filter algorithm to obtain the prediction route of the flying drone based on the accuracy assessment method. This proposed adaptive Kalman Filter is a high-efficiency algorithm that can filter out the noise in the multipath area and optimize the predicted data in real-time. The simulation result agrees well with the measured data and thus validates the proposed DOA system with the adaptive Kalman Filter algorithm. The measured DOA of the fixed radiation source obtained by a single base station and the moving route of a flying drone from a two-base station localization system are presented and compared with the calculated results. Results show that the prediction error in an outdoor region of is about 10–20 m, which demonstrate the usefulness of the proposed wireless DOA system deployment in practical applications.

A Wearable Capsule Endoscope Electromagnetic Localization System Based on a Novel WCL Algorithm.

The wearable localization system for wireless capsule endoscopy (WCE) is a potential technology to realize rapid diagnosis and treatment of the gastrointestinal (GI). However, the electromagnetic localization accuracy of WCE still needs to be improved. In this paper, based on RSSI electromagnetic fading model, the accurate fitting parameter values are obtained by Kalman filter and the least square method. A novel weighted centroid localization (WCL) algorithm based on exponential weights is proposed, which can achieve high-accuracy localization by using only sparse reception matrix. The simulation results show that when the standard deviation of the localization data is 7.85, the localization root mean square error (RMSE) is 25.4 mm; when the standard deviation of the localization data is 5.475, the localization RMSE is 2.5 mm. These two localization RMSEs are 38% and 79% less than those of the conventional centroid localization algorithm, respectively. An experimental platform of wearable wireless communication and localization system using 24 array receiving antennas is developed in human phantom environment. The experimental results show that the wearable WCE electromagnetic localization system based on the proposed algorithm achieves a localization RMSE of 36.3 mm, which is 17% lower than that of the conventional centroid localization algorithm and meets the needs of clinical diagnosis.

Automatic Landing of Unmanned Aerial Vehicles via Wireless Positioning System with Pseudo-Conical Scanning.

In this work, a wireless UAV unmanned landing system is considered, using the principles of pseudo conical scanning with a phased antenna array (PAA). The basic requirements for the characteristics and parameters of the system as a whole and of its components are defined. Special attention is paid to the primary sensor of the system—PAA with electronic scanning. A variant with a minimum number of four states on the radiation pattern of a low-budget patch PAA was studied. A linear regression of the difference characteristics of the measured radiation beams is proposed, which allows the practical application of the recommended landing algorithm with low computational complexity. Systematic and random positioning errors, both by measurement and by Monte Carlo simulation, were studied. Obtained statistical results prove the algorithm convergence and acceptable accuracy for the system implementation. They are applied if necessary to adjust the Kalman filter parameters. The proposed wireless system can be used for unmanned landing, tracking, and navigating the UAV in flight, or wireless navigation of other mobile objects.

To Hide Anchor’s Position in Range-Based Wireless Localization via Secret Sharing

The anchors in wireless network localization system suffer from the risk of location leakage, which may result in some catastrophic dangers. To preserve the location privacy of anchors, this letter proposes to hide the anchor’s position in range-based localization through a secret sharing method. By decomposing the private input of anchors into several secret shares and concealing it in the constant term of the secret polynomial, the location information of anchors cannot be disclosed by any other node in the network including the server, during the entire localization process. The performance of the proposed scheme in privacy preservation, positioning accuracy and efficiency improvement (i.e., low communication and computation costs) are evaluated through simulations.

Evaluation of a Wireless Localization System for Nonpalpable Breast Lesions - Feasibility and Cost-effectiveness in Everyday Clinical Routine.

Smaller, earlier-stage breast tumors are being found in breast cancer screening, and neoadjuvant chemotherapy is the gold standard when chemotherapy is indicated. Precise marking and localization of the tumor are thus becoming increasingly important. Wire-free localization techniques are under investigation in order to reduce presurgical radiography, pain, the risk of wire dislocation, and allow scheduling flexibility for patients and surgery departments. This single-center observational study from June 2020 to October 2021 included 15 patients with mammographically or sonographically detected nonpalpable breast lesions. Radiofrequency identification (RFID) tags were placed preoperatively under ultrasound or radiologic guidance to localize lesions for planned surgery. All patients underwent breast conservation surgery, including one bilateral and one targeted axillary dissection. Histology identified two benign and 13 malignant lesions, including three ductal carcinomas in situ and 11 invasive breast cancers. Placement, control radiography, and handling of the RFID tag were feasible in everyday routine for different radiologists and surgeons and managed cost-effectively. All of the RFID tags were found in the specimen radiographs. The feasibility and cost-effectiveness of this non-wire localization method were demonstrated in this rather small cohort of patients. Further studies including larger numbers of patients are needed to confirm the method's accuracy.

Information technologies for creating spatiotemporal modems multiposition active-passive radar systems

The methods of synthesis of the directional diagram of active transmitting antenna arrays when receiving signals reflected from radar targets are considered. It is shown that when using multifrequency orthogonal coherent signals in the elements and addressable access at their reception it is possible to provide a small level of the side lobes of the spatial uncertainty function in a given sector of observation by selecting the type of intrapulse modulation of partial signals. Orthogonalization of antenna basis of transmitting and receiving antennas allows digital spectral-correlation processing of samples of aggregate signal from each target to solve the technological problem of multidimensional observation space in multiposition systems of coherent radiolocation when detecting, resolving, estimating coordinates and motion parameters of targets. The results of simulation modeling of spatio-temporal radar modems implemented according to the stated principles are given.