In this context of changing and challenging market requirements, Gas Insulated Substation GIS has found a broad range of applications in power systems for more than two decades because of its high reliability, easy maintenance and small ground space requirement etc. SF6 has been of considerable technological interest as an insulation medium in GIS because of its superior insulating properties, high dielectric strength at relatively low pressure and its thermal and chemical stability. SF6 is generally found to be very sensitive to field perturbations such as those caused by conductor surface imperfections and by conducting particle contaminants.
Edit An imaging radar is a kind of radar equipment which can be used for imaging. A typical radar technology includes emitting radio waves, receiving their reflection, and using this information to generate data.
For an imaging radar, the returning waves Synthetic aperture radar thesis used to create an image. When the radio waves reflect Synthetic aperture radar thesis objects, this will make some changes in the radio waves and can provide data about the objects, including how far the waves traveled and what kind of objects they encountered.
Using the acquired data, a computer can create a 3-D or 2-D image of the target. Through wall radar imaging Wall parameter estimation uses Utra Wide-Band radar systems. The handle M-sequence UWB radar with horn and circular antennas was used for data gathering and supporting the scanning method.
In terms of speed and reliability for median-range operations, 3-D measurements have superior performance. Emerging technology utilizes monopulse radar 3-D imaging. Real aperture radar Edit Real aperture radar RAR is a form of radar that transmits a narrow angle beam of pulse radio wave in the range direction at tight angles to the flight direction and receives the backscattering from the targets which will be transformed to a radar image from the received signals.
Usually the reflected pulse will be arranged in the order of return time from the targets, which corresponds to the range direction scanning. The resolution in the range direction depends on the pulse width. The resolution in the azimuth direction is identical to the multiplication of beam width and the distance to a target.
Lidar Laser radar is a remote sensing technology that measures distance by illuminating a target with a laser and analyzing the reflected light. In all information gathering modes, lasers that transmit in the eye-safe region are required as well as sensitive receivers at these wavelengths.
Hence, an array of range counters is needed. A monolithic approach to an array of range counters is being developed. This technology must be coupled with highly sensitive detectors of eye-safe wavelengths. The returned laser energy must be mixed with a local oscillator in a heterodyne system to allow extraction of the Doppler shift.
The system architecture of 3-D, Multi-wave and Multi-band, Imaging radar is shown in the figure. Synthetic aperture radar Synthetic-aperture radar SAR is a form of radar which moves a real aperture or antenna through a series of positions along the objects to provide distinctive long-term coherent-signal variations.
This can be used to obtain higher resolution. SARs produce a two-dimensional 2-D image. One dimension in the image is called range and is a measure of the "line-of-sight" distance from the radar to the object.
Range is determined by measuring the time from transmission of a pulse to receiving the echo from a target. Also, range resolution is determined by the transmitted pulse width. The other dimension is called azimuth and is perpendicular to range.
The ability of SAR of producing relatively fine azimuth resolution makes it different from other radars. To obtain fine azimuth resolution, a physically large antenna is needed to focus the transmitted and received energy into a sharp beam.
The sharpness of the beam defines the azimuth resolution. An airborne radar could collect data while flying this distance and process the data as if it came from a physically long antenna. The distance the aircraft flies in synthesizing the antenna is known as the synthetic aperture.
A narrow synthetic beamwidth results from the relatively long synthetic aperture, which gets finer resolution than a smaller physical antenna.
Inverse synthetic aperture radar Inverse synthetic aperture radar ISAR is another kind of SAR system which can produce high-resolution on two- and three-dimensional images. An ISAR system consists of a stationary radar antenna and a target scene that is undergoing some motion.
ISAR is theoretically equivalent to SAR in that high-azimuth resolution is achieved via relative motion between the sensor and object, yet the ISAR moving target scene is usually made up of non cooperative objects.
ISAR technology uses the movement of the target rather than the emitter to make the synthetic aperture. ISAR radars are commonly used on vessels or aircraft and can provide a radar image of sufficient quality for target recognition.
The ISAR image is often adequate to discriminate between various missiles, military aircraft, and civilian aircraft.
There sometimes exists a reverse image. For example, the image formed of a boat when it rolls forwards and backwards in the ocean. When the Range-Doppler plane and the coordinate plane are different, the ISAR image can not reflect the real shape of the target.
Thus, the ISAR imaging can not obtain the real shape information of the target in most situations. Pitching is forward and backwards, yawing is turning left or right.Synthetic Aperture Radar (SAR) is a type of radar that uses the relative motion between a target and a sensor, which is usually placed on a platform, to produce .
UPDATED 12 September Preface.
When I was a boy, oddities fascinated me, particularly if they appeared to make no sense. Historical oddities or anomalous news stories especially attracted my interest, lingering in my mind for years to come.
Li, Yake () Frequency-modulated continuous-wave synthetic-aperture radar: improvements in signal processing.
Doctoral (PhD) thesis, Memorial University of Newfoundland. Electronic Thesis and Dissertation Repository January Monostatic Airborne Synthetic Aperture Radar Using Commercial WiMAX Transceivers In the License-exempt Spectrum Kai Liu The University of Western Ontario Supervisor Dr.
Xianbin Wang The University of Western Ontario Joint Supervisor. Interferometric synthetic aperture radar (InSAR), a very eﬁective technique for mea- suring crustal deformation, provides measurements in only one dimension, along the radar line of .
Husnul Kausarian, Josaphat Tetuko Sri Sumantyo, Dewandra Bagus Eka Putra, Adi Suryadi, and Gevisioner, “Image processing of ALOS PALSAR satellite data, small unmanned aerial vehicle (UAV), and field measurement of land deformation,” International Journal of Advances in Intelligent Informatics, Vol.4, No.2, pp, July