Download or read book Direction of Arrival Estimation for Wildlife Protection written by Gustav Zetterqvist and published by Linköping University Electronic Press. This book was released on 2024-10-03 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direction of arrival (DOA) estimation is a well-established problem in signal processing. It involves determining the direction from which a signal reaches a sensor array, and is fundamental in applications like radar, sonar, and acoustics. Traditionally, DOA estimation relies on comparing the time of arrival of the signal across different sensors in the array. However, this approach is sensitive to the time difference of arrival (TDOA) between sensors, which can be challenging to estimate accurately. Additionally, precise synchronization among the sensors is essential, but this can be difficult to achieve in certain environments or applications. In this thesis, we explore a novel approach to DOA estimation based on the received signal power at the sensors. The method exploits the directional sensitivity of the microphones in the array, which defines how effectively each microphone captures sound from different directions. To model the directional sensitivity, we use a Fourier series (FS) model. The model is then used to estimate the DOA of a sound source across various environments, and for different types of signals. The parametric model enables Cramér-Rao lower bound (CRLB) analysis of the DOA estimation problem. Our findings demonstrate that the directional sensitivity exhibits a significant variation in accordance with the frequency content of the signal, and we exploit this to estimate the DOA for different types of sounds. The proposed method has been validated with a range of signals, including gunshots, elephant trumpets, sirens, and female screams. The results show that the developed method achieves high accuracy in estimating the DOA for the above-mentioned signals. Furthermore, the method performs similarly well in outdoor scenarios with realistic background noise levels. When compared to state-of-the-art DOA estimation techniques, our approach performs better or equally well for the investigated sounds. A key advantage of this method is that it does not require any TDOA measurement between the microphones, enabling the design of smaller, more compact devices. This opens up new possibilities for estimating DOA in environments where traditional methods are impractical. A limitation, however, is that the method requires knowledge of the microphone’s directional sensitivity, which necessitates calibration in an anechoic chamber. Nevertheless, this calibration has proven to be robust, and only needs to be performed once to create a model applicable across different environments. Additionally, this thesis explores a different application of DOA estimation, where geophones are used to estimate the DOA to elephants. As elephants move, they generate ground vibrations, and these signals can be captured by geophones. We show that a traditional delay-and-sum beamformer can accurately estimate the DOA of elephants at distances up to 40 meters. By determining when elephants are approaching and from which direction, park rangers can take early measures to avoid conflicts between humans and elephants, which is a major problem in some parts of the world. Förmågan att höra var ett ljud kommer ifrån, något vi ofta tar för givet, kallas för riktningsuppfattning. Den gör det möjligt för oss att snabbt avgöra om någon ropar på oss och från vilket håll ljudet kommer. Denna förmåga är viktig för att kunna orientera sig i omgivningen och uppfatta hot eller andra viktiga ljud. Våra öron samarbetar genom att jämföra hur ljud når varje öra, både när det gäller ljudets intensitet och hur lång tid det tar för ljudet att nå dem. Det här kallas för interaural tids- och nivåskillnad. Vissa ljud kan dock vara svåra att uppfatta, till exempel om ljudet är kort och impulsivt, eller om det är i en stadsmiljö med mycket bakgrundsljud och reflektioner. I den här avhandlingen undersöker vi nya metoder för att uppskatta ljudets riktning. Vi använder mikrofoner för att mäta ljudet och beräknar därefter riktningen som ljudet kommer ifrån. Traditionella metoder fokuserar på tidsskillnaden mellan ljud som registreras i olika mikrofoner. Vi tar istället en annan väg och undersöker hur ljudets styrka kan användas för att avgöra riktningen, oavsett tidsskillnader mellan mikrofonerna. Vår metod bygger på att vi skapar en modell av mikrofonernas riktningskänslighet, det vill säga hur väl de uppfattar ljud från olika håll. Modellen skapas genom att mäta mikrofonens riktningskänslighet i ett ekofritt rum. Genom att först mäta detta i en kontrollerad miljö, utan ekon, kan vi sedan använda modellen för att beräkna ljudriktningen i mer varierande miljöer och för olika typer av ljud. Till exempel har vi använt ljud såsom pistolskott, elefanttrumpeter, sirener och skrik för att testa vår metod. Resultaten visar att vår metod kan beräkna riktningar med hög noggrannhet för de ovan nämnda ljuden, även i en utomhusmiljö med mer realistiska nivåer av bakgrundsljud. När vi jämfört vår metod med traditionella metoder, presterar vår lösning lika bra eller bättre för de testade ljuden. En stor fördel med vår metod är att den inte kräver att mikrofonerna är placerade på ett visst avstånd från varandra, vilket innebär att vi kan bygga mindre och mer kompakta enheter. Detta kan leda till nya typer av produkter för att identifiera ljudriktningar i olika situationer. En nackdel är dock att mikrofonernas riktningskänslighet måste kalibreras i ett ljudlabb, men denna kalibrering har visat sig vara robust och det räcker att utföra en kalibrering som kan användas i flera olika miljöer. I avhandlingen inkluderas även en annan tillämpning av riktningsskattning, nämligen att uppskatta riktningen till elefanter med hjälp av geofoner som mäter vibrationer i marken. Elefanter är stora djur som skapar tydliga vibrationer i marken när de går. Genom att mäta dessa vibrationer med geofoner kan vi uppskatta riktningen till elefanten. Vi visar att traditionella metoder kan uppskatta riktningen med hög noggrannhet på ett avstånd upp till 40 meter. Genom att avgöra när elefanter närmar sig människor och varifrån de kommer kan parkvakter vidta åtgärder för att undvika konflikter mellan människor och elefanter, vilket är ett stort problem i vissa delar av världen.

Download or read book Introduction to Direction of arrival Estimation written by Zhizhang Chen and published by Artech House Publishers. This book was released on 2010 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direction-of-Arrival (DOA) estimation concerns the estimation of direction finding signals in the form of electromagnetic or acoustic waves, impinging on a sensor or antenna array. DOA estimation is used for locatin and tracking signal sources in both civilian and military applications. This authoritative volume provides an overview and performance analysis of the basic DOA algorithms, including comparisons between the various types. The book offers you a detailed understanding of the arrays pertinent to DOA finding, and presents a detailed illustration of the ESPRIT-based DOA algorithms complete with their performance assessments. From antennas and array receiving systems, to advanced topics on DOA estimation, this book serves as a one-stop resource for professionals and students. Nearly 100 illustrations and more than 281 equations support key topics throughout.

Download or read book Ocean observation based on underwater acoustic technology written by Xuebo Zhang and published by Frontiers Media SA. This book was released on 2023-07-04 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Direction of Arrival Estimation Using High Altitude Platform written by Yasser Albagory and published by . This book was released on 2017-10-30 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Direction of Arrival Estimation Using ESPRIT Algorithm written by Alfred Tsz Yin Lok and published by . This book was released on 2011 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High resolution Direction of Arrival Estimation written by Murdifi Bin Muhammad and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Journal of the Acoustical Society of America written by Acoustical Society of America and published by . This book was released on 2007 with total page 1306 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Decentralized Direction of Arrival Estimation written by Wassim Suleiman and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Direction of arrival Estimation for Periodic sense High resolution and Low Complexity Applications written by Jafar Pourrostam and published by . This book was released on 2007 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nimbus 6 Random Access Measurement System Applications Experiments written by and published by . This book was released on 1982 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Techniques for Improving Direction of Arrival Estimation for Independent and Coherent Sources written by Mark D. Rosenstock and published by . This book was released on 1995 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Balanced Data Focusing Direction of Arrival Estimation with Maximum Likelihood Performance U written by Read, William J. L and published by . This book was released on 1994 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Two dimensional Direction of arrival Estimation with Time modulated Arrays written by Ben Clark and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Effects of System Imperfection on Direction of Arrival Estimation written by Juan Yin and published by . This book was released on 2000 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Robust Direction of Arrival Estimation and Spatial Filtering in Noisy and Reverberant Environments written by Soumitro Chakrabarty and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Review of the Administration s Proposal to Promote Dolphin Protection written by United States. Congress. House. Committee on Merchant Marine and Fisheries. Subcommittee on Fisheries and Wildlife Conservation and the Environment and published by . This book was released on 1992 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oceanic Abstracts written by and published by . This book was released on 1995-02 with total page 786 pages. Available in PDF, EPUB and Kindle. Book excerpt: