Radar cross section studies

The ultimate goal is to generate experimental techniques and computer codes of rather general capability that would enable the aerospace industry to evaluate the scattering properties of aerodynamic shapes. Another goal involves developing an understanding of scattering mechanisms so that modification of the vehicular structure could be introduced within constraints set by aerodynamics. The development of indoor scattering measurement systems with special attention given to the compact range is another goal. There has been considerable progress in advancing state-of-the-art scattering measurements and control and analysis of the electromagnetic scattering from general targets

Method for radar detection of persons wearing wires

PatentMethods are described for radar detection of persons wearing wires using radar spectra data including the vertical polarization (VV) radar cross section and the horizontal polarization (HH) radar cross section for a person. In one embodiment, the ratio of the vertical polarization (VV) radar cross section to the horizontal polarization (HH) radar cross section for a person is compared to a detection threshold to determine whether the person is wearing wires. In another embodiment, the absolute difference of the vertical polarization (VV) radar cross section and the horizontal polarization (HH) radar cross section for a person is compared to a detection threshold to determine whether the person is wearing wires. To reduce false positives, other additional indicators, such as speed of movement, and or visual features of the person, can be used to further narrow a person suspected of wearing wires

The radar cross section of dielectric disks

A solution is presented for the backscatter (nonstatic) radar cross section of dielectric disks of arbitrary shape, thickness and dielectric constant. The result is obtained by employing a Kirchhoff type approximation to obtain the fields inside the disk. The internal fields induce polarization and conduction currents from which the scattered fields and the radar cross section can be computed. The solution for the radar cross section obtained in this manner is shown to agree with known results in the special cases of normal incidence, thin disks and perfect conductivity. The solution can also be written as a product of the reflection coefficient of an identically oriented slab times the physical optics solution for the backscatter cross section of a perfectly conducting disk of the same shape. This result follows directly from the Kirchhoff type approximation without additional assumptions

A GTD analysis of ogive pedestal

The metal ogive pedestal is claimed to have low radar cross section and low observability features. This study uses the Geometric Theory of Diffraction (GTD) to analyze the pedestal scattering for three cases: direct backscattered field, backscattered field structure, and target/pedestal multiple scattering. This study can be used to evaluate the various ways that the metal conical ogive pedestal can effect the performance of a high quality radar cross section measurement system

Effects of range bin shape and Doppler filter response in a digital SAR data processor

In calibrating the backscatter coefficient obtained with an imaging synthetic aperture radar (SAR) system to determine absolute values of radar cross-section and reflectivity it is common practice to use a target of known radar cross-section placed within the scene. A corner reflector acts as a point target, but the return from it may not be centered in the resolution cell. It is important, for accurate calibration, to perform straddling corrections based on the range bin and Doppler filter response curves

Radar Cross Section of Orbital Debris Objects

This discussion is concerned with the radar-data analysis and usage involved in the building of model orbital debris (OD) populations in the near-Earth environment, focusing on radar cross section (RCS). While varying with radar wavelength, physical dimension, material composition, overall shape and structure, the RCS of an irregular object is also strongly dependent on its spatial orientation. The historical records of observed RCSs for cataloged OD objects in the Space Surveillance Network are usually distributed over an RCS range, forming respective characteristic patterns. The National Aeronautics and Space Administration (NASA) Size Estimation Model provides an empirical probability-density function of RCS as a function of effective diameter (or characteristic length), which makes it feasible to predict possible RCS distributions for a given model OD population and to link data with model from a statistical perspective. The discussion also includes application of the widely used method of moments (MoM) and the Generalized Multi-particle Mie-solution (GMM) in the prediction of the RCS of arbitrarily shaped objects. Theoretical calculation results for an aluminum cube are compared with corresponding experimental measurements

Radar Cross Section Studies/Compact Range Research

A summary is given of the achievements of NASA Grant NsG-1613 by Ohio State University from May 1, 1987 to April 30, 1988. The major topics covered are as follows: (1) electromagnetic scattering analysis; (2) indoor scattering measurement systems; (3) RCS control; (4) waveform processing techniques; (5) material scattering and design studies; (6) design and evaluation of design studies; and (7) antenna studies. Major progress has been made in each of these areas as verified by the numerous publications produced

Radar Studies of the Lunar Surface Emphasizing Factors Related to Selection of Landing Sites Status Report, 1 Jul. - 31 Dec. 1966

Mapping of lunar surface and measurement of radar cross section of moon for selection of landing sit

Evaluasi Desain Kapal Pengawas Perikanan Berbasis Radar Cross Section untuk Mengurangi Deteksi Radar di Wilayah Laut Natuna Utara

Sebagai negara kepulauan, Indonesia bersengketa dengan negara lain terkait klaim hak berdaulat di Laut Natuna Utara. Maka dari itu, diperlukan strategi pengawasan yang tepat untuk dapat mencegah dan memerangi illegal fishing di Laut Natuna Utara agar sumber daya ikan Indonesia dapat dilindungi dan berkelanjutan, serta tegaknya kedaulatan Indonesia. Sejak penemuannya, radar telah sangat memengaruhi semua domain peperangan militer, termasuk peperangan laut. Radar banyak digunakan di platform militer sebagai alat untuk mendeteksi, pelacakan, dan klasifikasi musuh. Radar cross section (RCS) adalah ukuran kekuatan reflektif suatu objek, untuk menentukan seberapa dini target dapat dideteksi. Reduksi RCS dari suatu kapal dapat menghambat deteksi radar kapal musuh. Pada desain awal Kapal Pengawas Perikanan tipe C, didapatkan nilai radar cross section sebesar 31 dBsm menggunakan metode numerik. Dilakukan evaluasi terhadap bentuk deckhouse untuk mengurangi luasan pantulan radar. Pada tahap evaluasi ini, didapatkan nilai radar cross section sebesar 30.6 dBsm. Kemudian dilakukan evaluasi terhadap bentuk lambung, bentuk lambung yang digunakan sebelumnya diubah menjadi bentuk inverted bow untuk mengurangi pantulan radar di daerah bow. Pada evaluasi lambung, didapatkan nilai radar cross section sebesar 30.4 dBsm. Kemudian dilakukan evaluasi terhadap pelapisan Radar Absorbing Material (RAM) pada deckhouse. Material yang digunakan adalah material komposit bernama BAM/PET. Pada evaluasi pelapisan RAM pada deckhouse didapatkan nilai radar cross section sebesar 1.9 dBsm. Dilakukan pelapisan RAM pada kapal awal sebelum dilakukan evaluasi deckhouse dan lambung, hasil pelapisan RAM pada kapal awal menunjukkan nilai radar cross section sebesar 3.7 dBsm. Nilai tersebut sudah memenuhi kriteria radar cross section kapal. Sehingga tidak perlu dilakukan evaluasi terhadap bentuk deckhouse dan lambung, cukup melakukan pelapisan RAM pada kapal untuk mengurangi nilai radar cross section pada kapal. Hasil evaluasi tersebut kemudian digunakan untuk mendesain Lines Plan, General Arrangement, dan 3D Model