Target Identification Problem Research Articles

Recursive temporal-spatial information fusion with applications to target identification

Centralized/distributed recursive algorithms for temporal-spatial information integration using the Dempster-Shafer technique are developed. Compared with the Bayesian approach, the Dempster-Shafer technique has the strong capability of handling information uncertainties, which are particularly desirable in many applications. In the centralized integration algorithm, all information is pooled into the central processor and integrated. In contrast, the distributed integration algorithm shares the computational burden among the local processors, which increases the computational efficiency. The developed algorithms are effectively applied to a target identification problem with three sensors: identification of friend-foe-neutral (IFFN), electronic support measurement (ESM), and infrared search and track (IRST). >

High resolution radar target modeling using a modified Prony estimator

A method for characterizing radar signatures using a Prony model is developed based on the concept of scattering centers. A parameterization of the Prony model specific to the radar target identification problem is chosen and several key components to the algorithm, including the use of singular value decomposition and the removal of spurious scattering centers, are presented. The resulting algorithm is tested with data taken from a compact range. These tests include comparison of different targets, different aspect angles and frequency ranges, as well as robustness tests on the algorithm and evaluation of performance in noise. >

Biological oceanography and bioacoustics: Promises, pitfalls, and idiosyncratic perspectives.

Populations of marine animals vary significantly in abundance over a broad range of time and space scales. It is almost certainly the case that the time and space scales of biological and physical processes are related but are so in a highly complex and nonlinear manner. Documenting and understanding the dynamics of this linkage has become a major intellectual focus for biological oceanography. The technical challenge implicit is the development of appropriate sampling and measurement systems. Although fisheries acoustics has received considerable attention, acoustic sampling of microzooplankton, macrozooplankton, and micronekton (organisms ranging from ca. 0.05 mm to a few centimeters) is in its comparative infancy. Nonetheless, results obtained to date have both stimulated the biological oceanographic community and occasioned major new funding initiatives within the federal agencies. Perhaps the potential that has most greatly contributed to the general excitement is the possibility of sampling biological structure on scales heretofore beyond reach, of sampling biological variability concomitantly with physical variability. Not surprisingly, once these possibilities were explored, a set of inherent difficulties became obvious. Perhaps the least tractable of all is the problem of target identification. For some ecological inquiries this is a critical lacuna of acoustical methodology. For others it may turn out to be less critical than first thought. To some degree, our community has converged upon the notion that if acoustical methods can be efficiently combined with alternative technologies (and the principal candidates have to date been optical) the target identification problem can be contained if not overcome.

Predicting the transient EM response of complex structures using the compact finite-element method

The compact finite-element model (CFEM) method has been used to model the transient EM (TEM) response of an earth model consisting of a heterogeneous prism in a two-layered, conducting halfspace. The prism can be deformed to simulate any angle of dip and plunge without the effect of 'staircasing'. The present implementation of CFEM (program Samaya) allows for a horizontal-loop transmitter with arbitrarily oriented magnetic dipole receivers which may be on the surface or downhole. Samaya can be run on workstations or on augmented IBM PC-AT's (or clones).The use of Samaya should allow the TEM method to be used to solve a greater range of structural and target identification problems than is possible with existing interpretation aids. Having the ability to predict the TEM response of an expected geology means that surveys can be designed to yield optimum information. The program can also be used to validate hypothesized structural models against field data.The paper concludes with a discussion of the computed downhole TEM response of a dipping target.