Power lines: radar measurements and detection algorithm for polarimetric SAR images

Abstract

REFERENCES 632Vorperian, V. (1990) Simplified analysis of PWM converters using the model of the PWM switch: Parts I and 11. A unified analysis of PWM converters in discontinuous modes. IEEE Transaction onPower Electronics, 6, 3 (July 1991). A general unified approach to modelling switching dc-to-dc converters in discontinuous conduction mode. IEEE Power Electronics Specialists Conference Record, 1977, pp. 36-57; IEEE Publication 77 CH 12-13-8AES. Current injected equivalent circuit approach to modeling of switching dc-dc converters in discontinuous inductor conduction mode. One cycle control of switching converters. IEEE Paver Electronics Specialists Conference Record, 1990, pp. 88%8% IEEE Publication 91CH3008-0. Modelling, analysis, and design of switching converters. Ph.D. dissertation, California Institute of Technology, Pasadena, Nov. 1976.A general unified approach to modelling switching converter power stages.On the use of averaging for the analysis of power electronic systems.Polarimetric radar backscattering measurements of a variety of powerline cables are presented. The objective of the first part of the investigation was to study the effect of braiding of the cables on the backscattering at skew incidence. The measurements were performed for four different actual size powerline samples at C-, X-, and Ka-band over a wide range of incidence angles.The data were collected over a 500 MHz bandwidth at C-and Xband with a 1.25 MHz increment and a 1 GHz bandwidth at Ka-band with a 2 5 MHz increment. Also the effect of nonuniform illumination and measurement in the near field of the cables were studied. Experimental data shows a significant radar backscatter for W-polarization (U"") at angles away from normal incidence. This backscatter is proportional to the number and diameter of the strands on the surface of the cables. There is also noticeable backscatter for the HH and MI components of the scattering matrices. Their magnitudes, relative to that of the W component, are proportional to the pitch angle of the helix.Since detection of these cables is an important safety issue for low-flying airplanes a detection algorithm using polarimetric synthetic aperture radar (SAR) images was developed using the knowledge gleaned from the measurements.The detection algorithm was tested on a simulated image and worked well, detecting a power line whose backscatter power was 6 dB below the average background power.

Extraction of power line maps from millimeter-wave polarimetric SAR images

“…The level of backscatter drops significantly at higher angles which is why the detection of power lines using conventional radars is not possible. Experimental results at Ka-and W-band also show the trends predicted by the model [5], [6].…”

“…5, it is obvious that the coherence of the pixels with power lines is a function of clutter backscattering coefficients, power-line aspect angle, and the power-line RCS. RCS of power lines increases with increasing frequency especially at aspect angles beyond for normal (see typical RCS values at Ka-band and W-band reported in [5] and [6]). However, the backscattering of clutter at millimeter-wave frequency is not a strong function of frequency.…”

“…The problem of power-line detection with poor signalto-clutter was first considered in [5] where a polarimetric detection algorithm was proposed. The performance of this algorithm was demonstrated under laboratory conditions and the results were reported in [6].…”

A radar cross-section model for power lines at millimeter-wave frequencies

“…The field produced by this current does not include the effect of multiple scattering, which gives rise to cross-polarized backscatter. Experimental results show [2], [7] that at high frequencies (W band and higher) the effect of multiple scattering on the surface of power lines becomes significant. The so-called multiple scattering is caused by the periodic helical arrangement of wire strands.…”

Robust power line detection with particle-filter-based tracking in radar video

“…A series of works have been developed in [11,12] to model and measure the backscattering characteristics of power lines in active millimeter-wave radar, which is utilized in [7] to develop a power line detection algorithm. PMMW imaging systems have gone through a growing stage [13].…”