Accession Number : ADA549382


Title :   An EM System With Dramatic Multi-Axis Transmitter and Tensor Gradiometer Receiver


Descriptive Note : Final rept. 2006-2010


Corporate Author : G AND G SCIENCES INC GRAND JUNCTION CO


Personal Author(s) : George, David C ; Snyder, D D


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA549382


Report Date : Jun 2011


Pagination or Media Count : 85


Abstract : The objective of the work was to demonstrate that sensor pairs could be used to adequately approximate the spatial gradients of the vector dB/dt field and to test if the use of sensor differences improved or degraded the quality of data compared to conventional measurements. An array of four, small, three-component sensors was shown to be useful to approximate the spatial gradient tensor when the target was not exceedingly c lose to the sensors. Computations using the gradient tensor are simpler and faster than conventional computations and offer opportunities for improved target resolution and separation of multiple overlapping signatures. Efficient computations were implemented and tested. Subtracting signals from pairs of sensors decreases signal and also decreases noise, so signal to noise ratio can be better. Measurements showed that differences signals improved signal to noise ratio in situations that are typically encountered in target detection surveys but neither improved nor degraded SNR in situations typically encountered in cued identification and characterization surveys.


Descriptors :   *ELECTROMAGNETIC INDUCTION , *GRADIOMETERS , *TENSORS , ARRAYS , COMPUTATIONS , DETECTORS , ELECTROMAGNETIC RADIATION , GRADIENTS , IDENTIFICATION , NOISE , QUALITY , RATIOS , RECEIVERS , RESOLUTION , SEPARATION , SIGNALS , SPATIAL DISTRIBUTION , SURVEYS , TARGET DETECTION , TARGETS , TEST AND EVALUATION , TRANSMITTERS


Subject Categories : Electricity and Magnetism


Distribution Statement : APPROVED FOR PUBLIC RELEASE