Trådlös kommunikation mellan noder sker genom att skicka data över det trådlösa mediet, för att få kommunikationen att samspela har flertalet standarder utvecklats. En av dessa standarder är 802.15.4 med UWB PHY vars utformning är av en sådan karaktär att signalöverföringen blir störningstålig och osynlig för andra standarder. UWB används ofta till lokalisering och positionering, men kan även användas till en samtida dataöverföring då standardens utformning tillåter detta. Det var dock oklart med vilken prestanda detta kunde genomföras. Därför har den datakommunikationsprestandan undersöks. Den hypotes som följdes under arbetet var att ''genom att skicka data mellan positioneringsimpulserna möjliggörs användandet av samma enhet för positionering och datakommunikation, systemets prestanda påverkas då av MAC-metoden''. Ur hypotesen kom det tre frågeställningar: Vilken MAC-metod är lämplig för både positionering och dataöverföring? Är det möjligt att använda systemet för både positionering och dataöverföring genom att skicka data mellan positioneringsimpulserna? Vilken kommunikationsprestanda kan uppnås när systemet används för både postionering och dataöverföring? I arbetet bevisas hypotesen samt frågeställningarna med syftet att detta kunde komma att hjälpa till inom exempelvis robotiken, men även som ett alternativ till WiFi då UWB är både störningståligt och osynligt för andra standarder. Den iterativa metoden användes för att utveckla ett system som kunde lösa den kombinerade positioneringen och datakommunikationen. I prestandatesterna gick det att utläsa att hypotesen stämde förutsatt att parametrarna är korrekt. / Wireless communication between nodes is achieved by sending data over the wireless medium. In order to have communications interact different standards have been developed. One such standard is 802.15.4 with UWB PHY, designed such that the signal transmission becomes interference-resistant and invisible to other standards. UWB is often used for location and positioning, but the standard design also allows for a contemporary data transfer. However, it was unclear with what performance this could be implemented. Therefore, the data communication performance has been investigated. The hypothesis that was followed during the work posits that ''by sending data between the positioning pulses, the use of the same unit for positioning and data communication is made possible, and that the system's performance is then affected by the MAC method.'' Three questions arose from this hypothesis. Which MAC method is suitable for both positioning and data transfer? Is it possible to use the system for both positioning and data transmission by sending data between the positioning pulses? What communication performance can be achieved when the system is used for both positioning and data transfer? In this work the hypothesis and the research questions are verified with the intended purpose that it could be of help in the field of robotics and also as an alternative to WiFi, due to UWBs robustness and invisibility characteristics. An iterative process has been utilized throughout this work to build a system which could solve the combined positioning and data communication. In the following performance tests the hypothesis is verified, provided that the parameters used are correct.

In recent years, the indoor positioning system (IPS) has attracted significant interests in both academical research and industrial development. It has seen many applications, such as hostage search and rescue, indoor navigation, and warehouse management, all of which can take advantage of precise positioning. However, in indoor environments, traditional methods, like the Global Positioning System (GPS), are usually either unreliable or incorrect because of the complicated physical characteristics of various objects reflecting and dispersing signals, such as the presence of people, walls, obstructions, and furniture. In contrast to other technologies such as WiFi and Bluetooth, which are not suitable to extract accurate timing information, UWB technology has the potential to reach center-meter level accuracy in indoor positioning. In this thesis, we developed a real-time, low-cost, IPS based on commercial-off-the-shelf UWB transceivers. Both the Two Way Ranging (TWR) and Time Difference of Arrival (TDOA) approaches have been implemented to obtain a target's location. To alleviate the effect of multipath propagation, we detect the presence of outliers by comparing the first path signal level and estimated receiving signal level. Moreover, we have designed the Printed Circuit Board (PCB) and evaluated performance by deploying the system both in a lab environment and in a two-story historical building during the 2018 Microsoft Indoor Localization Competition. The results show that we achieve a 28.9cm 95%-quantile 2D tracking error in the lab environment and a 92cm average tracking error for 3D localization on the Microsoft Indoor Localization Competition site. / Thesis / Master of Science (MSc)

Direction finding with radio-frequency (RF) waves have numerous applications in radio navigation, wireless localization, emergency aid, and air traffic control, among others. Direction-finding using digital arrays outperforms traditional analog techniques but requires precise knowledge of the location of the array elements to obtain accurate results. Array perturbations can lead to algorithm failures and false detection, compromising direction-finding capabilities. This research proposes implementing a Matched Filter - Least Square (MF-LS) algorithm for Two-Way Ranging (TWR) to enhance direction-finding accuracy in arrays with perturbed element locations. The MF-LS algorithm leverages the properties of matched filters to accurately determine element positions by measuring the Time of Flight (ToF) of a signal between two ranging nodes. This method is independent of GPS or other sensor data, making it a cost-effective and easily deployable solution aimed at minimizing the effects of array perturbations, thus improving direction-finding accuracy. This work validates the MF-LS algorithm efficacy and enables robust direction-finding capabilities in challenging environments where traditional communication and localization services are unavailable. Moreover, this research provides a comprehensive study of direction-finding accuracy in amateur radio bands using the proposed ranging approach which can provide an immediate low-cost option for search and rescue operations in emergency situations.

abstract: Within the near future, a vast demand for autonomous vehicular techniques can be forecast on both aviation and ground platforms, including autonomous driving, automatic landing, air traffic management. These techniques usually rely on the positioning system and the communication system independently, where it potentially causes spectrum congestion. Inspired by the spectrum sharing technique, Communications and High-Precision Positioning (CHP2) system is invented to provide a high precision position service (precision ~1cm) while performing the communication task simultaneously under the same spectrum. CHP2 system is implemented on the consumer-off-the-shelf (COTS) software-defined radio (SDR) platform with customized hardware. Taking the advantages of the SDR platform, the completed baseband processing chain, time-of-arrival estimation (ToA), time-of-flight estimation (ToF) are mathematically modeled and then implemented onto the system-on-chip (SoC) system. Due to the compact size and cost economy, the CHP2 system can be installed on different aerial or ground platforms enabling a high-mobile and reconfigurable network. In this dissertation report, the implementation procedure of the CHP2 system is discussed in detail. It mainly focuses on the system construction on the Xilinx Ultrascale+ SoC platform. The CHP2 waveform design, ToA solution, and timing exchanging algorithms are also introduced. Finally, several in-lab tests and over-the-air demonstrations are conducted. The demonstration shows the best ranging performance achieves the ~1 cm standard deviation and 10Hz refreshing rate of estimation by using a 10MHz narrow-band signal over 915MHz (US ISM) or 783MHz (EU Licensed) carrier frequency. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2020

In den letzten Jahrzehnten sind Satellitennavigationssysteme zu einem unverzichtbaren Teil des modernen Lebens geworden. Viele innovative Anwendungen bieten ortsabhängige Dienste an, welche auf diesen Navigationssystemen aufbauen. Allerdings sind diese Dienste in Innenräumen nicht verfügbar. Daher werden seit einigen Jahren alternative Lokalisierungsmethoden für Innenräume aktiv erforscht und entwickelt. Der Schwerpunkt dieser Arbeit liegt darauf, die Genauigkeit von Lokalisationsmethoden in Innenräumen zu erhöhen, sowie auf der effektiven Integration der entsprechenden Verfahren in drahtlose Kommunikationssysteme. Es werden zwei Ansätze vorgeschlagen und untersucht, welche die Präzision von ToF-basierten Methoden erhöhen. Zum einen wird im „Modified Equivalent Time Sampling“ (METS) Verfahren eine überabgetastete Version der vom Radioempfänger gelieferten Wellenform erzeugt und zur ToF Bestimmung verwendet. Der zweite erforschte Ansatz hat zum Ziel, Fehler auf Grund von Taktfrequenz-Abweichungen zu kompensieren. Dieses ist für kooperative Lokalisationsmethoden (N-Way ranging) von Bedeutung. Das in der Arbeit entwickelte Verfahren führt zu einer erheblichen Reduzierung der Fehler in der Abstandsmessung und damit der Positionsbestimmung. Darüber hinaus wurde eine neue Methode untersucht, um Lokalisationsverfahren in Funksysteme für die ISM Bänder bei 2,4 GHz und 5 GHz zu integrieren. Die Methode wurde auf einer Software Defined Radio (SDR) Plattform implementiert und bewertet. Es konnte eine Genauigkeit bis zu einem Meter in der Positionsbestimmung demonstriert werden. Schließlich wurde ein Verfahren vorgeschlagen und untersucht, mit welchem Lokalisationsfähigkeit in bestehende Funksysteme integriert werden kann. Die betrachtete Methode wurde in einem 60 GHz Funksystem mit hoher Datenrate implementiert. Die Untersuchungen zeigten eine Positionsgenauigkeit von 1 cm bei einer gleichzeitig hohen Datenrate für die Übertragung von Nutzdaten. / In the last couple of decades the Global Navigation Satellite Systems (GNSS) have become a very important part of our everyday life. A huge number of applications offer location based services and navigation functions which rely on these systems. Nevertheless, the offered localization services are not available indoors and their performance is significantly affected in urban areas. Therefore, in the recent years, a large number of wireless indoor localization systems are being actively investigated and developed. The main focus of this work is on improving precision and accuracy of indoor localization systems, as well as on the implementation and integration of localization functionality in wireless data transmission systems. Two approaches for improving the localization precision and accuracy of ToF based methods are proposed. The first approach, referred to as modified equivalent time sampling (METS) is used to reconstruct an oversampled versions of the waveforms acquired at the radio receiver and used for ToF based localization. The second proposed approach is used to compensate the ranging error due to clock frequency offset in cooperative localization schemes like N-Way ranging. This approach significantly reduces the ranging and, therefore, localization errors and has much better performance compared to the existing solutions. An approach for implementation of localization system in the 2.4/5 GHz ISM band is further proposed in this work. This approach is implemented and tested on a software defined radio platform. A ranging precision of better than one meter is demonstrated. Finally, an approach for integrating localization functionality into an arbitrary wireless data transmission system is proposed. This approach is implemented in a 60 GHz wireless system. A ranging precision of one centimeter is demonstrated.