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ABSTRACT: Millimeterwave radars at Ka- and W-band are state of the art and are used as well for civilian as military applications. The higher atmospheric windows, 140 GHz and 220 GHz, are not widely used to date. With the advance of automotive and security applications requiring short and medium range radars, these frequency bands become an interesting alternative. At the same time technology to expand radar use to the upper millimeterwave bands becomes available. An experimental radar has been designed and built using the most advanced solid state technology available in this frequency region. The paper describes the radar set-up at 220 GHz and gives results achieved with this instrument.
Infrared, Millimeter and Terahertz Waves, 2008. IRMMW-THz 2008. 33rd International Conference on; 10/2008
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ABSTRACT: In a world, where terrorism is threatening human life in particular that of those forces and civilian personnel who are involved in peace keeping and peace enforcing missions, the defence against snipers is a necessary safety demand. For this purpose sensor systems based upon various principles are in use and still under development. Among those acoustic and electro optical sensors are the most common ones; however their performance is very often limited with respect to their ability to cope with dust, fog and haze, especially in urban terrain. Notably here the millimeter wave radar could offer the additional advantage of small, light weight miniature sensors with the capability to fulfill the demands of an urban environment. As a first step to develop a millimeter wave radar system as a part a multi sensor approach, the signature characteristics of typical sniper projectiles have been investigated. RCS simulations have been conducted, which were validated by measurements under well controlled conditions. The paper gives results from this work and discusses the implications on the design of a respective sniper detection approach.
Radar Conference, 2008. RADAR '08. IEEE; 06/2008
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ABSTRACT: An experimental radar at 220 GHz has been developed which is capable of delivering an instantaneous bandwidth of 8000 MHz. The solid-state radar uses an FM-CW waveform. The development is based on experience with a 94 GHz broadband measurement radar. The data undergo an ISAR imaging process to derive high-resolution scattering centre distributions for targets measured in tower/turntable configuration. High-resolution processing algorithms have been developed which result in scattering centre distributions with a resolution better than 2 cm at ranges of and exceeding 200 m. The radar will be used for investigations on target signatures of small objects for stand-off detection of concealed weapons and other threat material.
Electronics Letters 02/2007; · 0.96 Impact Factor
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Fraunhofer FHR.
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Fraunhofer FHR.
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ABSTRACT: There are many applications of millimetre wave radar sensors, which rely on the knowledge of high resolution scattering centre distributions. To derive those, the method of Inverse Synthetic Aperture Radar (ISAR) is employed. The target under test is positioned on a turntable while the radar is illuminating the target from a tower. Existing experimental instruments have approached resolutions of about 10 to 20 cm. The effort described here, however, should exceed this limit to be able to test the necessity of extremely high resolutions in radar images. The range resolution of radar is determined by its instantaneous bandwidth. At higher millimetre wave bands even moderate relative bandwidths are equivalent to high absolute bandwidth. For the development of related processing algorithms an experimental, polarimetric 94-GHz radar has been developed using a FM/CW waveform with a bandwidth of 4000 MHz resulting in a resolution better than 4 cm. The radar has been tested using the method of Inverse Synthetic Aperture in tower-/turntable geometry. To be able to derive ISAR images with the full theoretically achievable resolution, a fast polar reformatting process was developed and tested with the data. The paper describes the hardware approach, which is based on high performance monolithically integrated GaAs components and most recent signal generation and processing hardware. The ISAR algorithm is discussed and representative examples of highly resolved ISAR images shown. In addition first results of a SAR experiment with this newly developed millimetre wave radar on top of a moving tower against stationary targets are presented.
Fraunhofer FHR.
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ABSTRACT: Based upon most recent advances in millimeterwave technology, especially monolithic integrated low noise or medium power HEMT amplifiers and multi channel receivers, a miniaturized experimental radar at 94 GHz was designed with the aim to be used on board of a remotely piloted model aircraft. This highly advanced front-end technique was combined with of-the-shelf model aircraft hardware and miniaturized GPS and data transmission equipment which is readily available. Goal of the project is to demonstrate, that using modern 94-GHz front-end technique combined with achievable back-end components it is possible under the already known advantages of the higher millimeterwave bands with respect of ease of SAR data processing, to set up a versatile SAR system usable for a wide range of remote sensing applications at medium range. The paper describes the current state of the research project SUMATRA-94 and gives some perspectives for future applications.
Fraunhofer FHR.
