To counter radio signal reconnaissance, an efficient way of covert communication is to use subsecond duration burst transmissions in the congested HF band. Against this background, the present thesis treats fast direction finding using antenna arrays with known response only in a few calibration directions. In such scenarios the known method of array mapping (interpolation) may be used to trans...

Beamforming remains one of the most common methods for estimating the Direction Of Arrival (DOA) of an acoustic source. Beamformers operate using at least two sensors that look among a set of geometrical directions for the one that maximizes received signal power. In this paper we consider a two-sensor beamformer that estimates the DOA of a single source by scanning the broadside for the direct...

The synovial fluids of patients with a destructive form of osteoarthritis (DOA) were shown to contain high levels of bone resorbing activity as judged by the ability of the fluid to stimulate the release of 45Ca from labelled cultured mouse calvariae. The activity was lost on extended storage of the synovial fluids and was dependent for its effect on cellular activity in bone. Bone resorbing ac...

This paper describes investigations into Direction–Of– Arrival (DOA) estimation of a wideband signal by a two– dimensional array antenna, which employs only spatial signal processing for beam forming. The elements of this array are arranged in a horizontal rectangular lattice to steer a beam in azimuth over a wide frequency band. By applying the concept of interpolated array, a composite covari...

In signal processing, the direction of arrival (DOA) estimation denotes the direction from which a propagating wave arrives at a point, where a set of antennas is located. Using the array antenna has an advantage over the single antenna in achieving an improved performance by applying Multiple Signal Classification (MUSIC) algorithm. This paper focuses on estimating the DOA using uniform linear...

The estimation of direction of arrival (DOA) of a smart antenna is not able to perform high resolution in a mixed noise field with high correlation. In this paper, a modified multiple signal classification (MUSIC) algorithm based on spatial difference is proposed for improving the resolution of DoA estimation. The algorithm can eliminate the effect of mixed noise through computing the differenc...

This paper investigates the benefit of mutual coupling compensation via a method of moments (MoM) approach in a uniform circular antenna array operating at 1.8 GHz. This mutual coupling compensation technique is applied to a direction of arrival (DOA) study of up to two cochannel mobile users. Field measurements and computer simulations are examined to explore the assumptions of the technique a...

This paper proposes a DOA(Direction Of Arrival) estimation system using chip sized phase shifters and a single ADC(Analogue to Digital Converter) and Rx(Receiver) module under the antenna elements[1]. The proposed system is only controlled by the phase of antenna to find the DOA of target. To obtain the low cost and portable DOA system[2] used as surveillance system in outdoor, we propose a mod...

The majority of algorithms developed for the narrowband direction of arrival (DOA) estimation problem rely on an eigenvalue decomposition (EVD) to determine both the number of signals and their respective DOAs. In this paper, an alternative algorithm is presented that solves both the DOA detection and estimation problems without resorting to an EVD. The algorithm is shown to have asymptotically...

In order to solve the problem of poor real-time performance, low accuracy and high computational complexity in the traditional process of locating and tracking of Direction of Arrival (DOA) of moving targets, this paper proposes a DOA algorithm based on the Direction Lock Loop (DILL) which adopts Lock Loop structure to realize the estimation and location of DOA and can adjust the direction auto...