2-D Phased Array Processing In Bulk Wave Acoustic Media

1988 ◽  
Author(s):  
R M. Montgomery ◽  
J W. Watkins
Keyword(s):  
Phased Array ◽  
Array Processing ◽  
Bulk Wave ◽  
Acoustic Media

Phased Array Ultrasonic Technique Parametric Evaluation for Composite Materials

2014 ◽  
Author(s):  
Hossein Taheri ◽  
Katrina M. Ladd ◽  
Fereidoon Delfanian ◽  
Jikai Du
Keyword(s):  
Composite Materials ◽  
Phased Array ◽  
Composite Plates ◽  
Single Element ◽  
Bulk Wave ◽  
Plate Wave ◽  
High Attenuation ◽  
Array Transducer ◽  
General Improvement ◽  
Aluminum Plates

A series of ultrasonic elements arranged in a phased array transducer can provide the capability to activate each element separately but in a programmed sequence. This will help the acoustic signal to be generated at desired focusing distances and anticipated angles for specific materials and structures. In case of composite material inspection, this characteristic of the phased array method can improve the undesirable effects of the high attenuation and anisotropic structure of composite materials on response signals. In this study different phased array probes and wedges which are commercially available were evaluated for their response signals’ characteristics. First, the capability and resolution of bulk wave generation were studied for each set of probe and wedge, and the response signals were compared to that of the conventional single element ultrasonic transducers for different thicknesses composite plates. Then the resolution of the response signals and their sensitivity to defect size were evaluated and compared to the single element transducers as well. Next, each phased array probe and wedge set was used to generate plate waves in aluminum plates based on plate wave propagation theory, probe and wedge physical properties and the definition of delay law. Results show a general improvement in response signals’ strength and resolution for phased array method in comparison to the single element transducers. Also some plate wave modes could be generated with optimized signal generation parameters in phased array system.

Finding the boom: Phased array processing applied to sonic boom direction of arrival estimation

2017 ◽  
Vol 16 (4-5) ◽  
pp. 230-254
Author(s):  
Todd Schultz ◽  
James R Underbrink ◽  
LC Hunting ◽  
James Giannakis ◽  
Matthew D Moore ◽  
...  
Keyword(s):  
Wave Front ◽  
Phased Array ◽  
Array Processing ◽  
Time Estimation ◽  
Direction Of Arrival ◽  
Test Point ◽  
Propagation Path ◽  
Sonic Boom ◽  
Circular Aperture ◽  
Aperture Diameter

From 29 October 2012 to 7 November 2012, 73 supersonic passes of an F-18 aircraft were observed over a dry lake bed at Edwards Air Force Base as part of NASA’s Farfield Investigation of No-boom Thresholds project, which was conceived to measure the characteristics of sonic booms at the boundaries of their decay, where overpressure is exceptionally low, thereby stretching the limits of current prediction methods. Each pass was recorded by a 55-microphone phased array sensor system with a circular aperture diameter of 2000 ft (609.6 m). The data were processed using a novel time domain array processing algorithm to estimate the direction of arrival and trace speed of the sonic boom wave front along the plane of the phased array. The results from the phased array processing are consistent with the known location of the test aircraft for each processed flight and are consistent with expectations for direction of arrival due to atmospheric refraction. Near real-time estimation of the sonic boom direction of arrival, trace speed along the ground, and visualization of the propagation of the sonic boom wave front are possible. This could allow the test team to assess the data and determine if the target of the test point has been met while the test aircraft is still in flight. This would enable improved test efficiency and efficacy, ultimately improving the value of the test campaign. The measured direction of arrival also provides sonic boom propagation numerical prediction code validation. Most sonic boom prediction codes provide the propagation path of the sonic boom and thus the direction of arrival of the sonic boom at a point on the ground. Thus for predictions made using the actual flight data measured at the time of the test, the predicted direction of arrival and measured direction of arrival can be directly compared to help validate the prediction codes.

scholarly journals Aspects of the Subarrayed Array Processing for the Phased Array Radar

2015 ◽  
Vol 2015 ◽  
pp. 1-21 ◽  
Author(s):  
Hang Hu
Keyword(s):  
Phased Array ◽  
Array Processing ◽  
Direction Finding ◽  
Adaptive Beamforming ◽  
Fast Time ◽  
Configuration Optimization ◽  
Numerical Examples ◽  
Phased Array Radar ◽  
Time Space ◽  
Space Time Adaptive Processing

This paper gives an overview on the research status, developments, and achievements of subarrayed array processing for the multifunction phased array radar. We address some issues concerning subarrayed adaptive beamforming, subarrayed fast-time space-time adaptive processing, subarray-based sidelobe reduction of sum and difference beam, subarrayed adapted monopulse, subarrayed superresolution direction finding, subarray configuration optimization in ECCM (electronic counter-countermeasure), and subarrayed array processing for MIMO-PAR. In this review, several viewpoints relevant to subarrayed array processing are pointed out and the achieved results are demonstrated by numerical examples.

Calibration of microphone arrays for phased array processing

1997 ◽  
Author(s):  
Marianne Mosher ◽  
Michael Watts ◽  
Srba Jovic ◽  
Stephen Jaeger ◽  
Marianne Mosher ◽  
...  
Keyword(s):  
Phased Array ◽  
Array Processing ◽  
Microphone Arrays

scholarly journals Ghost artifact cancellation using phased array processing

2001 ◽  
Vol 46 (2) ◽  
pp. 335-343 ◽  
Author(s):  
Peter Kellman ◽  
Elliot R. McVeigh
Keyword(s):  
Phased Array ◽  
Array Processing
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