Utilizing Near-Field Measurements to Characterize Far-Field Radar Signatures
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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The increased need for stealth aircraft requires an on-site Far-Field FF Radar Cross-Section RCS measurement process. Conducting these measurements in on-site Near-Field NF monostatic facilities results in significant savings for manufacturers and acquisition programs. However, NF measurements are not directly extended to a FF RCS. Therefore, a large target Near-Field to Far-Field Transformation NFFFT is needed for RCS measurements. One approach requires an Inverse Synthetic Aperture Radar ISAR process to create accurate scattering maps. The focus of this work is the development of accurate NF scattering maps generated by a monostatic ISAR process. As a first look, the process is isolated to a simulated environment to avoid the uncontrollable effects of real measurement environments. The simulation begins with a NF Synthetic Target Generator STG which approximates a target using scattering centers illuminated by spherical electromagnetic waves to approximating NF scattering. The resulting NF In-phase and Quadrature IQ data is used in a Trapezoidal ISAR process to create spatially distorted images that are accurately corrected within the ISAR process resolution using a newly developed NF correction. The resulting spatially accurate ISAR images do not complete the NFFFT. However, accurate scattering maps are essential for process development.
- Active and Passive Radar Detection and Equipment
- Radiofrequency Wave Propagation