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Title: GMTI processing using back projection.

Abstract

Backprojection has long been applied to SAR image formation. It has equal utility in forming the range-velocity maps for Ground Moving Target Indicator (GMTI) radar processing. In particular, it overcomes the problem of targets migrating through range resolution cells.

Authors:
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1090227
Report Number(s):
SAND2013-5111
460303
DOE Contract Number:
AC04-94AL85000
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English

Citation Formats

Doerry, Armin Walter. GMTI processing using back projection.. United States: N. p., 2013. Web. doi:10.2172/1090227.
Doerry, Armin Walter. GMTI processing using back projection.. United States. doi:10.2172/1090227.
Doerry, Armin Walter. 2013. "GMTI processing using back projection.". United States. doi:10.2172/1090227. https://www.osti.gov/servlets/purl/1090227.
@article{osti_1090227,
title = {GMTI processing using back projection.},
author = {Doerry, Armin Walter},
abstractNote = {Backprojection has long been applied to SAR image formation. It has equal utility in forming the range-velocity maps for Ground Moving Target Indicator (GMTI) radar processing. In particular, it overcomes the problem of targets migrating through range resolution cells.},
doi = {10.2172/1090227},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2013,
month = 7
}

Technical Report:

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  • Expressions for the fan beam and parallel beam projection and back-projection operators are given along with an evaluation of the point source response for the back-projection operators. The back-projection operator for the fan beam geometry requires the superposition of projection data measured over 360/sup 0/. Both the fan beam and parallel beam geometries have back-projection operators with point source responses which are proportional to 1/mod (r-r/sub 0/), and thus two-dimensional Fourier filter techniques can be used to reconstruct transverse sections from fan beam and parallel beam projection data. The two-dimensional Fourier filter techniques may have the speed over other methodsmore » for reconstructing fan beam data, but the reconstructed image requires four times the core storage so that the convolution result of one period does not overlap the convolution result of the succeeding period when implementing the fast Fourier transform. 10 figures.« less
  • The resolution and error properties of the Back Projection Technique (BPT) for geophysical tomography are examined. It is demonstrated that: (a) the BPT algorithm always converges in the vector space corresponding to the non-zero eigenvectors; (b) the mean error in the solution after convergence is the projection of the difference between the mean values of the starting model and the real solution in the vector space corresponding to the zero eigenvectors; and (c) the covariance of the mean error is always finite. The resolving properties and error propagation characteristics of BPT for various tomographic views are discussed. In general, themore » resolving power and error propagation characteristics of BPT are improved with tomograhic views which encircle the region under investigation. Finally, exploration strategy for geotomograhy with the BPT algorithm is discussed. The trade-off between the resolving area and parameter contrast, cell size, and data accuracy is examined.« less
  • Ground Moving Target Indicator (GMTI) radar maps echo data to range and range-rate, which is a function of a moving target's velocity and its position within the antenna beam footprint. Even stationary clutter will exhibit an apparent motion spectrum and can interfere with moving vehicle detections. Consequently it is very important for a radar to understand how stationary clutter maps into radar measurements of range and velocity. This mapping depends on a wide variety of factors, including details of the radar motion, orientation, and the 3-D topography of the clutter.
  • The performance of a Ground Moving Target Indicator (GMTI) radar system depends on a variety of factors, many which are interdependent in some manner. It is often difficult to 'get your arms around' the problem of ascertaining achievable performance limits, and yet those limits exist and are dictated by physics. This report identifies and explores those limits, and how they depend on hardware system parameters and environmental conditions. Ultimately, this leads to a characterization of parameters that offer optimum performance for the overall GMTI radar system. While the information herein is not new to the literature, its collection into amore » single report hopes to offer some value in reducing the 'seek time'.« less
  • Minimum detectable velocity (MDV) is a fundamental consideration for the design, implementation, and exploitation of ground moving-target indication (GMTI) radar imaging modes. All single-phase-center air-to-ground radars are characterized by an MDV, or a minimum radial velocity below which motion of a discrete nonstationary target is indistinguishable from the relative motion between the platform and the ground. Targets with radial velocities less than MDV are typically overwhelmed by endoclutter ground returns, and are thus not generally detectable. Targets with radial velocities greater than MDV typically produce distinct returns falling outside of the endoclutter ground returns, and are thus generally discernible usingmore » straightforward detection algorithms. This document provides a straightforward derivation of MDV for an air-to-ground single-phase-center GMTI radar operating in an arbitrary geometry.« less