Direction of arrival estimation in sensor arrays with faulty elements

Külbay, Tayfun
During the operational lifetime of a sensor array, certain sensors cease to operate properly. The identification of these sensors is an important problem. Furthermore, the operation of the array is continued even with the faulty sensors. Therefore, new techniques are required in order to ensure that the system estimation performance does not degrade significantly. In this thesis, two different fault types in a sensor array are considered. The first fault type is special to MEMS microphone arrays. MEMS microphones are usually constructed with pairwise sensors which share the common data channel in positive and negative cycles of a clock signal. When one of the MEMS microphones is faulty, same data is seen for both of the microphone channels and determining the faulty sensor becomes a major problem. A new technique is developed to determine the faulty microphone based on the use of a source with known direction-of-arrival (DOA). This approach can find the faulty sensor or sensors accurately in low SNR depending on the source position with respect to the array. In a second fault type, it is assumed that each sensor’s fault is associated with a probability. In other words, a sensor is either on or off with a probability “p” at any time. This problem is investigated in the literature before and G-MUSIC algorithm is proposed for a consistent DOA estimation. In this thesis, the problem scenario is investigated and a new approach is proposed to estimate the DOA with a faulty sensor array. It is shown that the performance of the proposed algorithm is better than G-MUSIC.


Communication Coverage in Wireless Passive Sensor Networks
Bereketli, Alper; Akan, Ozgur B. (2009-02-01)
System lifetime of wireless sensor networks (WSN) is inversely proportional to the energy consumed by critically energy-constrained sensor nodes during RF transmission. In that regard, modulated backscattering (MB) is a promising design choice, in which sensor nodes send their data just by switching their antenna impedance and reflecting the incident signal coming from an RF source. Hence, wireless passive sensor networks (WPSN) designed to operate using MB do not have the lifetime constraints of convention...
Wireless Measurement of Elastic and Plastic Deformation by a Metamaterial-Based Sensor
Ozbey, Burak; DEMİR, Hilmi Volkan; Kurç, Özgür; ERTÜRK, VAKUR BEHÇET; ALTINTAŞ, AYHAN (2014-10-01)
We report remote strain and displacement measurement during elastic and plastic deformation using a metamaterial-based wireless and passive sensor. The sensor is made of a comb-like nested split ring resonator (NSRR) probe operating in the near-field of an antenna, which functions as both the transmitter and the receiver. The NSRR probe is fixed on a standard steel reinforcing bar (rebar), and its frequency response is monitored telemetrically by a network analyzer connected to the antenna across the whole ...
Temperature compensation of a capacitive mems accelerometer by using a mems oscillator
Kose, Talha; Azgın, Kıvanç; Akın, Tayfun (2016-02-25)
This study reports a temperature compensation method for a capacitive MEMS accelerometer by using a MEMS double-ended-tuning-fork (DETF) resonator integrated with the accelerometer structure on the same die. The proposed method utilizes the frequency information of the clamped-clamped DETF resonator which is oscillating in a closed-loop operation. In order to compensate the temperature dependence of the accelerometer output, frequency drift of the DETF resonator against changing temperature is used, i. e., ...
Use of Acoustic and Vibration Sensor Data to Detect Objects in Surveillance Wireless Sensor Networks
Kucukbay, Selver Ezgi; SERT, MUSTAFA; Yazıcı, Adnan (2017-05-31)
Nowadays, people are using stealth sensors to detect intruders due to their low power consumption and wide coverage. It is very important to use lightweight sensors for detecting real time events and taking actions accordingly. In this paper, we focus on the design and implementation of wireless surveillance sensor network with acoustic and seismic vibration sensors to detect objects and/or events for area security in real time. To this end, we introduce a new environmental sensing based system for event tr...
Road Target Search and Tracking with Gimballed Vision Sensor on an Unmanned Aerial Vehicle
Skoglar, Per; Orguner, Umut; Tornqvist, David; Gustafsson, Fredrik (2012-07-01)
This article considers a sensor management problem where a number of road bounded vehicles are monitored by an unmanned aerial vehicle (UAV) with a gimballed vision sensor. The problem is to keep track of all discovered targets and simultaneously search for new targets by controlling the pointing direction of the vision sensor and the motion of the UAV. A planner based on a state-machine is proposed with three different modes; target tracking, known target search, and new target search. A high-level decisio...
Citation Formats
T. Külbay, “Direction of arrival estimation in sensor arrays with faulty elements,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Electrical and Electronics Engineering., Middle East Technical University, 2020.