Development of real-time indoor human tracking system using LoRa technology

<p>Industrial growth has increased the number of jobs hence increase the number of employees. Therefore, it is impossible to track the location of all employees in the same building at the same time as they are placed in a different department. In this work, a real-time indoor human tracking system is developed to determine the location of employees in a real-time implementation. In this work, the long-range (LoRa) technology is used as the communication medium to establish the communication between the tracker and the gateway in the developed system due to its low power with high coverage range besides requires low cost for deployment. The received signal strength indicator (RSSI) based positioning method is used to measure the power level at the receiver which is the gateway to determine the location of the employees. Different scenarios have been considered to evaluate the performance of the developed system in terms of precision and reliability. This includes the size of the area, the number of obstacles in the considered area, and the height of the tracker and the gateway. A real-time testbed implementation has been conducted to evaluate the performance of the developed system and the results show that the system has high precision and are reliable for all considered scenarios.</p>

Modified Skin Incision and Location of Burr-Hole Surgery via a Retrosigmoid Approach: An Anatomical Study

Objective This study aims to reduce the tissue damage during craniotomy with retrosigmoid approach. A modified sickle-shaped skin incision was developed, and a new burr-hole positioning method was proposed. Methods Five adult cadaveric heads (10 sides) were used in this study. The sickle-shaped skin incision was performed during craniotomy. The nerves, blood vessels, and muscles were observed and measured under a microscope. Additionally, 62 dry adult skull specimens (left sided, n = 35; right sided, n = 27) were used to measure the distance between the most commonly used locating point (asterion [Ast] point) and the posteroinferior point of the transverse sigmoid sinus junction (PSTS) (Ast-PSTS), as well as the distance between the new locating O point and the PSTS (O-PSTS). Then, the reliability of the new locating O point was validated on the same five adult cadaveric heads (10 sides) used for the sickle-shaped skin incision. Results The sickle-shaped skin incision reduced the damage to the occipital nerves, blood vessels, and muscles during the surgery via a retrosigmoid approach. The dispersion and variability of O-PSTS were smaller than those of Ast-PSTS. Conclusion The sickle-shaped skin incision of the retrosigmoid approach can reduce the tissue damage and can completely expose the structures in the cerebellopontine angle. The modified O point is a more reliable locating point for a burr-hole surgery than the Ast point.

Positioning Localities for Vague Spatial Location Description: A Supervaluation Semantics Approach

In the big data era, spatial positioning based on location description is the foundation to the intelligent transformation of location-based-services. To solve the problem of vagueness in location description in different contexts, this paper proposes a positioning method based on supervaluation semantics. Firstly, through combing the laws of human spatial cognition, the types of elements that people pay attention to in location description are clarified. On this basis, the source of vagueness in the location description and its embodiment in the expression form of each element are analyzed from multiple levels. Secondly, the positioning model is constructed from the following three aspects: spatial object, distance relation and direction relation. The contexts of multiple location description are super-valued, respectively, while the threshold of observations is obtained from the context semantics. Thus, the precisification of location description is realized for positioning. Thirdly, a question-answering system is designed to the collect contexts of location description, and a case study on the method is conducted. The case can verify the transformation of a set of users’ viewpoints on spatial cognition into the real-world spatial scope, to realize the representation of vague location description in the geographic information system. The result shows that the method proposed in the paper breaks through the traditional vagueness modeling, which only focuses on spatial relationship, and enhances the interpretability of semantics of vague location description. Moreover, supervaluation semantics can obtain the precisification results of vague location description in different situations, and the positioning localities are more suitable to individual subjective cognition.

Integrity Monitoring of PPP-RTK Positioning; Part I: GNSS-Based IM Procedure

Nowadays, integrity monitoring (IM) is required for diverse safety-related applications using intelligent transport systems (ITS). To ensure high availability for road transport users for in-lane positioning, a sub-meter horizontal protection level (HPL) is expected, which normally requires a much higher horizontal positioning precision of, e.g., a few centimeters. Precise point positioning-real-time kinematic (PPP-RTK) is a positioning method that could achieve high accuracy without long convergence time and strong dependency on nearby infrastructure. As the first part of a series of papers, this contribution proposes an IM strategy for multi-constellation PPP-RTK positioning based on global navigation satellite system (GNSS) signals. It analytically studies the form of the variance-covariance (V-C) matrix of ionosphere interpolation errors for both accuracy and integrity purposes, which considers the processing noise, the ionosphere activities and the network scale. In addition, this contribution analyzes the impacts of diverse factors on the size and convergence of the HPLs, including the user multipath environment, the ionosphere activity, the network scale and the horizontal probability of misleading information (PMI). It is found that the user multipath environment generally has the largest influence on the size of the converged HPLs, while the ionosphere interpolation and the multipath environments have joint impacts on the convergence of the HPL. Making use of 1 Hz data of Global Positioning System (GPS)/Galileo/Beidou Navigation Satellite System (BDS) signals on L1 and L5 frequencies, for small- to mid-scaled networks, under nominal multipath environments and for a horizontal PMI down to , the ambiguity-float HPLs can converge to 1.5 m within or around 50 epochs under quiet to medium ionosphere activities. Under nominal multipath conditions for small- to mid-scaled networks, with the partial ambiguity resolution enabled, the HPLs can converge to 0.3 m within 10 epochs even under active ionosphere activities.

Development and Implementation of High Precision Positioning Technology for Electric Vehicle Wireless Charging Coils

This paper mainly studies the development and implementation of the positioning technology of the electric vehicle wireless charging coil, so as to accurately detect the position deviation of the receiving coil, so that the electric vehicle wireless charging system can provide electric energy for electric vehicles more efficiently. Based on the positioning method of electric vehicle based on three detection coils, this paper proposes a calculation method to describe the offset degree of coil based on fuzzy mathematics theory. The algorithm is verified by simulation and experiment, and the influence factors of the error accuracy and the source of the error are analyzed. The work done in this paper has a strong practical significance for the efficient realization of electric vehicle wireless energy transmission.

Research on 3D Fingerprint Positioning Based on MIMO Base Station

The aim of this article is to solve the problem that the accuracy of traditional positioning algorithm decreases in complex environment and to provide some ideas for the few researches of fingerprint localization algorithm in three-dimensional space. This paper builds a system model in a three-dimensional space, provides three reference point distribution methods, and discusses the positioning performance under these distribution methods. After that, based on the high base station deployment density, multi-point fusion positioning method is used to locate the target, which further improves the positioning accuracy and makes more effective use of reference point resources. Finally, a backward-assisted positioning method is proposed, which uses the position information of the positioned points to assist the positioning of the current point. Research shows that this method can improve the positioning accuracy and has good versatility. (Foundation items: Social Development Projects of Jiangsu Science and Technology Department (No.BE2018704).)

High-Performance Fingerprint Localization in Massive MIMO System

Location-based service (LBS) for both security and commercial use is becoming more and more important with the rise of 5G. Fingerprint localization (FL) is one of the most efficient positioning methods for both indoor and outdoor localization. However, the positioning time of previous research cannot achieve real-time requirement and the positioning error is meter level. In this paper, we concentrated on high-performance in massive multiple-in-multiple-out (MIMO) systems. Principal Component Analysis (PCA) is applied to reduce the dimension of fingerprint, so that the positioning time is about tens of milliseconds with lower storage. What’s more, a novel fingerprint called Angle Delay Fingerprint (ADF) is proposed. Simulation result of the positioning method based on ADF shows the positioning error is about 0.3 meter and the positioning time is about hundreds of milliseconds, which is much better than other previous known methods. (Foundation items: Social Development Projects of Jiangsu Science and Technology Department (No.BE2018704).)