Atlas Elektronik

About: Atlas Elektronik is a company organization based out in Dorchester, United Kingdom. It is known for research contribution in the topics: Signal & Sonar. The organization has 594 authors who have published 780 publications receiving 2914 citations.

An Experimental and Numerical Investigation Into the Mechanisms of Rotating Instability

Abstract: This paper reports on an experimental and numerical investigation aimed at understanding the mechanisms of rotating instabilities in a low speed axial flow compressor. The phenomena of rotating instabilities in the current compressor were first identified with an experimental study. Then, an unsteady numerical method was applied to confirm the phenomena and to interrogate the physical mechanisms behind them. The experimental study was conducted with high-resolution pressure measurements at different clearances, employing a double phase-averaging technique. The numerical investigation was performed with an unsteady 3-D Navier-Stokes method that solves for the entire blade row. The current study reveals that a vortex structure forms near the leading edge plane. This vortex is the result of interactions among the classical tip-clearance flow, axially reversed endwall flow, and the incoming flow. The vortex travels from the suction side to the pressure side of the passage at roughly half of the rotor speed. The formation and movement of this vortex seem to be the main causes of unsteadiness when rotating instability develops. Due to the nature of this vortex, the classical tip-clearance flow does not spill over into the following blade passage. This behavior of the tip-clearance flow is why the compressor operates in a stable mode even with the rotating instability, unlike traditional rotating stall phenomena.Copyright © 2001 by ASME

Calculation of moments of complex Wishart and complex inverse Wishart distributed matrices

Abstract: The calculation of moments of complex Wishart and complex inverse Wishart distributed random matrices is addressed. In applications such as radar, sonar or seismics, complex Wishart and complex inverse Wishart distributed random matrices are used to model the statistical properties of complex sample covariance matrices and complex inverse sample covariance matrices, respectively. Moments of these random matrices are often needed, for example, in studies of the asymptotic properties of parameter estimates. A derivation of the probability density function of complex inverse Wishart distributed random matrices is given. Furthermore, strategies are outlined for the calculation of the moments of both complex Wishart and complex inverse Wishart distributed matrices.

Modern swathe sounding and sub-bottom profiling technology for research applications: The Atlas Hydrosweep and Parasound Systems

Abstract: This chapter describes two separate but complementary research echosounder systems originally developed by Krupp Atlas Elektronik GmbH for the new German oc3anographic research vessel Meteor.

Fuzzy technology implemented in sonar systems

Abstract: Applications of fuzzy algorithms in the domain of sonar systems that have been implemented in the latest generation of Atlas sonar equipment are introduced. The aim is to provide an insight into the solution of problems from an application-oriented point of view. Classification of DEMON spectra and automatic target tracking by means of fuzzy systems are introduced and demonstrated with examples. A short introduction to fuzzy technology is given to support the understanding of the algorithms presented. >

AIS Adding New Quality to VTS Systems

Abstract: In the foreseeable future, Automatic Identification Systems (AIS) will be installed aboard all sea-going ships larger than 300 grt These new devices broadcast data at regular and short intervals, by means of which the ship can be identified and tracked Further data can be transmitted to provide additional information on the ship's motion, navigational status, intended voyage and cargo The transmissions can be received by every interested party having an appropriate receiver both at sea and ashore With these capabilities, AIS adds a new information quality to maritime traffic, which is relevant not only for ship/ship but also for VTS/ship interaction This paper describes the genesis of the new systems and their operational and technical aspects It continues with a discussion of their standard and extended applications and their - so far - unexploited potential Where relevant, the results of R&D work and practical tests are mentioned