Hybrid Radio-map for Noise Tolerant Wireless Indoor Localization

In wireless networks, radio-map based locating techniques are commonly used to cope the complex fading feature of radio signal, in which a radio-map is built by calibrating received signal strength (RSS) signatures at training locations in the offline phase. However, in severe hostile environments, such as in ship cabins where severe shadowing, blocking and multi-path fading effects are posed by ubiquitous metallic architecture, even radio-map cannot capture the dynamics of RSS. In this paper, we introduced multiple feature radio-map location method for severely noisy environments. We proposed to add low variance signature into radio map. Since the low variance signatures are generally expensive to obtain, we focus on the scenario when the low variance signatures are sparse. We studied efficient construction of multi-feature radio-map in offline phase, and proposed feasible region narrowing down and particle based algorithm for online tracking. Simulation results show the remarkably performance improvement in terms of positioning accuracy and robustness against RSS noises than the traditional radio-map method.Comment: 6 pages, 11th IEEE International Conference on Networking, Sensing and Control, April 7-9, 2014, Miami, FL, US

Design and theoretical analysis of advanced power based positioning in RF system

Accurate locating and tracking of people and resources has become a fundamental requirement for many applications. The global navigation satellite systems (GNSS) is widely used. But its accuracy suffers from signal obstruction by buildings, multipath fading, and disruption due to jamming and spoof. Hence, it is required to supplement GPS with inertial sensors and indoor localization schemes that make use of WiFi APs or beacon nodes. In the GPS-challenging or fault scenario, radio-frequency (RF) infrastructure based localization schemes can be a fallback solution for robust navigation. For the indoor/outdoor transition scenario, we propose hypothesis test based fusion method to integrate multi-modal localization sensors. In the first paper, a ubiquitous tracking using motion and location sensor (UTMLS) is proposed. As a fallback approach, power-based schemes are cost-effective when compared with the existing ToA or AoA schemes. However, traditional power-based positioning methods suffer from low accuracy and are vulnerable to environmental fading. Also, the expected accuracy of power-based localization is not well understood but is needed to derive the hypothesis test for the fusion scheme. Hence, in paper 2-5, we focus on developing more accurate power-based localization schemes. The second paper improves the power-based range estimation accuracy by estimating the LoS component. The ranging error model in fading channel is derived. The third paper introduces the LoS-based positioning method with corresponding theoretical limits and error models. In the fourth and fifth paper, a novel antenna radiation-pattern-aware power-based positioning (ARPAP) system and power contour circle fitting (PCCF) algorithm are proposed to address antenna directivity effect on power-based localization. Overall, a complete LoS signal power based positioning system has been developed that can be included in the fusion scheme --Abstract, page iv

A Self Regulating and Crowdsourced Indoor Positioning System through Wi-Fi Fingerprinting for Multi Storey Building

[EN] Unobtrusive indoor location systems must rely on methods that avoid the deployment of large hardware infrastructures or require information owned by network administrators. Fingerprinting methods can work under these circumstances by comparing the real-time received RSSI values of a smartphone coming from existing Wi-Fi access points with a previous database of stored values with known locations. Under the fingerprinting approach, conventional methods suffer from large indoor scenarios since the number of fingerprints grows with the localization area. To that aim, fingerprinting-based localization systems require fast machine learning algorithms that reduce the computational complexity when comparing real-time and stored values. In this paper, popular machine learning (ML) algorithms have been implemented for the classification of real time RSSI values to predict the user location and propose an intelligent indoor positioning system (I-IPS). The proposed I-IPS has been integrated with multi-agent framework for betterment of context-aware service (CAS). The obtained results have been analyzed and validated through established statistical measurements and superior performance achieved

TESTBED SECURE INDOOR LOCALIZATION SYSTEM MENGGUNAKAN CLUSTER BASED PATHLOSS EXPONENTIAL UNTUK ESTIMASI POSISI DI LINGKUNGAN INDOOR PADA WIRELESS SENSOR NETWORK

Wireless Sensor Network has become one of the topics that has been researched lately, both for indoor positioning system applications (IPS), tracking objects and monitoring systems. However, efforts made to produce better accuracy values on IPS using the received signal strength value are still not optimal. In addition, when the process of sending data from one device to another device, the data received needs to be maintained in its originality and confidentiality. Thus, the IPS required the addition of a Secure Indoor Localization System (SI-LOCS) scenario to maintain the confidentiality of information during the data transmission process. In this study, SI-LOCS analysis with Raspberry PI 3 was conducted using Cluster Based Pathway Exponential (CBPLE) to increase the accuracy value of the position estimation process using received signal strength values and AES 128 and MD5 Hash Function Security Algorithms. The test results show that the accuracy of the Indoor Positioning System uses a CBPLE of 99.89% while compared to the previous scenario without using CBPLE of 93.85%. The security algorithm used to secure position data from reference nodes and object nodes when the data exchange process shows satisfactory performance and has fulfilled the requirements of confidentiality and data integrity. It is expected that SI-LOCS can be implemented for various IPS applications

Comprehensive analysis of distance and similarity measures for Wi-Fi fingerprinting indoor positioning systems

Recent advances in indoor positioning systems led to a business interest in those applications and services where a precise localization is crucial. Wi-Fi fingerprinting based on machine learning and expert systems are commonly used in the literature. They compare a current fingerprint to a database of fingerprints, and then return the most similar one/ones according to: 1) a distance function, 2) a data representation method for received signal strength values, and 3) a thresholding strategy. However, most of the previous works simply use the Euclidean distance with the raw unprocessed data. There is not any previous work that studies which is the best distance function, which is the best way of representing the data and which is the effect of applying thresholding. In this paper, we present a comprehensive study using 51 distance metrics, 4 alternatives to represent the raw data (2 of them proposed by us), a thresholding based on the RSS values and the public UJIIndoorLoc database. The results shown in this paper demonstrate that researchers and developers should take into account the conclusions arisen in this work in order to improve the accuracy of their systems. The IPSs based on k-NN are improved by just selecting the appropriate configuration (mainly distance function and data representation). In the best case, 13-NN with Sørensen distance and the powed data representation, the error in determining the place (building and floor) has been reduced in more than a 50% and the positioning accuracy has been increased in 1.7 m with respect to the 1-NN with Euclidean distance and raw data commonly used in the literature. Moreover, our experiments also demonstrate that thresholding should not be applied in multi-building and multi-floor environments

Optimum NN Algorithms Parameters on the UJIIndoorLoc for Wi-Fi Fingerprinting Indoor Positioning Systems

Wi-Fi fingerprinting techniques are commonly used in Indoor Positioning Systems (IPS) as Wi-Fi signal is available in most indoor settings. In such systems, the position is estimated based on a matching algorithm between the enquiry points and the recorded fingerprint data. In this paper, our objective is to investigate and provide quantitative insight into the performance of various Nearest Neighbour (NN) algorithms. The NN algorithms such as KNN are also often employed in IPS. We extensively study the performance of several NN algorithms on a publicly available dataset, UJIIndoorLoc. Furthermore, we propose an improved version of the Weighted KNN algorithm. The proposed model outperforms the existing works on the UJIIndoorLoc dataset and achieves better results for the success rate and the mean positioning error

A Self Regulating and Crowdsourced Indoor Positioning System through Wi-Fi Fingerprinting for Multi Storey Building

Unobtrusive indoor location systems must rely on methods that avoid the deployment of large hardware infrastructures or require information owned by network administrators. Fingerprinting methods can work under these circumstances by comparing the real-time received RSSI values of a smartphone coming from existing Wi-Fi access points with a previous database of stored values with known locations. Under the fingerprinting approach, conventional methods suffer from large indoor scenarios since the number of fingerprints grows with the localization area. To that aim, fingerprinting-based localization systems require fast machine learning algorithms that reduce the computational complexity when comparing real-time and stored values. In this paper, popular machine learning (ML) algorithms have been implemented for the classification of real time RSSI values to predict the user location and propose an intelligent indoor positioning system (I-IPS). The proposed I-IPS has been integrated with multi-agent framework for betterment of context-aware service (CAS). The obtained results have been analyzed and validated through established statistical measurements and superior performance achieved

A Performance Evaluation of Modified Weighted Pathloss Scenario Based on the Cluster Based-PLE for an Indoor Positioning of Wireless Sensor Network

The indoor positioning system is one of the popular topics in the current study; it is mainly due to the inability of the Global Positioning System (GPS) applied inside a building. LANDMARC (Location Identification based on Dynamic Active RFID Calibration) and Enhanced LANDMARC Scenario use calibration RSSI values and weighted process to obtain accuracy of position estimation. Meanwhile, WPL (Weighted Pathloss) method improves the positioning accuracy of the two previous methods (LANDMARC and Enhanced LANDMARC) by observing the Path Loss Exponent (PLE) value in an indoor environment, followed by using the value to estimate the object position. We propose a Modified WPL uses Cluster Based Pathloss Exponent (PLE) method by combining the functions of the existing calibration in LANDMARC Scenario with the Cluster Based PLE value. The test bed was conducted in an indoor area on the 3rd floor of the PENS Postgraduate Building. The nodes were connected to each other using X-Bee Pro S2 module. RSSI (Received Signal Strength Indicator) value was used to estimate the distance between transmitter and receiver nodes. The result of the MSE estimation position using the proposed method was 3.80 meters, whereas WPL method was 5.78 meters. Overall, the proposed Modified WPL with Cluster Based PLE method showed that it had the capability to enhance the accuracy of localization; 34% better than the standard WPL method

Indoor localization techniques using wireless network and artificial neural network

This research focuses on improving indoor localization using wireless network and artificial neural network (ANN). This involves strategic study on wireless signal behavior and propagation inside buildings, suitable propagation model to simulate indoor propagation and evaluations on different localization methods such as distance based, direction based, time based and signature based. It has been identified that indoor signal propagation impairments are severe, non-linear and custom to a specific indoor location. To accommodate these impairments, an ANN is proposed to provide a viable solution for indoor location prediction as it learns the location specific parameters during training, and then performs positioning based on the trained data, while being robust to severe and non-linear propagation effects. The versatility of ANN allows different setup and optimization possibilities to affect location prediction capabilities. This research identified the best feedforward backpropagation neural network configuration for the generated simulation data and introduced a new optimization method. Indoor-specific received signal strength data were developed with the Lee’s in-building model according to a custom indoor layout. Simulation work was done to test localization performance with different feedforward backpropagation neural network setups with the generated received signal strength data as input. A data preparation method that converts the received signal strength raw data into average, median, min and max values prior to be fed into the neural network process was carried out. The method managed to increase location prediction performance using feedforward neural network with two hidden layers trained with Bayesian Regularization algorithm producing root mean squared error of 0.0821m, which is 50% better in comparison to existing research work. Additional tests conducted with six different relevant scenarios verified the scheme for localization performance robustness. In conclusion, the research has improved the performance of indoor localization using wireless network and ANN

Position estimation in indoor localization with trilateration

Triangulateration uses geometric distance to estimate the location of user by employing techniques like received signal strength (RSS), time-of-arrival (TOA), time-difference-of-arrival (TDOA) and image processing. Radio frequency (RF) signal positioning using TOA or TDOA techniques generally requires timing synchronization of the anchors and/or the anchors and targets. If the desired position accuracy is high and coverage area is large, timing synchronization will be an extremely challenging issue. The first part of this dissertation focuses on improving the performance or deployability of indoor localization systems. Specifically, we propose a synchronization-free positioning network architecture that eliminates the need of timing synchronization. Another problem that remains unsolved in RF based localization is the non-line-of-sight (NLOS) problem, which greatly degrades the positioning performance. We propose a semidefinite programing (SDP) with a soft-minimal method and an NLOS link identification method with bias deduction to mitigate the NLOS error TOA systems. For TDOA systems, NLOS mitigation is more difficult since a reference should be fixed first. To overcome this problem, we propose a method to transform the TDOA architecture into a TOA one, and then form a SDP problem with new constraints. To avoid the special problems and difficulties in RF signal positioning, such as the synchronization and NLOS problems, in the second part of the dissertation, we propose an image-tag based localization using image processing and convolutional neural network (CNN). In the proposed method, after the segmentation of the tag from the image, information such as the tag ID, the distance, and the angle with reference to the camera are retrieved through CNNs. The camera position is finally reliably and accurately estimated from such retrieved information. The proposed method simplifies the system and provide good accuracy compare to RF based system. In addition, the proposed method effectively resolve those issues that exist in the traditional image-based localization, like the high cost, blind spot problems and unreliable and not scalable for in changing environments.Keywords: Convolutional neural network (CNN), Wi-Fi, Image, UWB, Algorithm, Localizatio