Radar systems

The inverse-fourth-power dependence of SNR on target distance is a severe limitation in ground-based observations, but it can be overcome by constructing very powerful radar systems. 

The world has two active planetary radar facilities the Arecibo Observatory (part of the National Astronomy and Ionosphere Center) in Puerto Rico and the Goldstone 

The Arecibo telescope (Fig. 2) consists of a 305-m-diameter, fixed reflector whose siuface is a 51 -m-deep section of a 265-m-radius sphere. Moveable feeds designed to correct for spherical aberration are suspended from a triangular platform 137 m above the reflector and can be aimed toward various positions on the reflector, enabling 

FIGURE 2 The Arecibo Observatory in Puerto Rico, (a) Aerial view prior to the recent upgrade. The diameter of the spherical reflector is 305 m. (b) A close-up view of the structure suspended above the reflector, showing the old 430-MHz line feed and the radome that encloses the new Gregorian secondary and tertiary subreflectors. 

Greenbank Telescope, now under construction in West Virginia, should prove advantageous for outer planet satellites and nearby asteroids and comets. 

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A. V. Jelahan, Laser Radar Systems, Artech House, Boston, Mass., 1992. 

Many ideas for advancing electrical and electronic systems have been adopted since the early 1940s, which saw the start of high electronic frequency radar systems. The earliest major use of plastics for electrical insulation early in last century come with the advent of developments in electrical... 

Range resolution is the ability of a radar system to distinguish two closely spaced targets at differing ranges. In monostatic radar this is primarily a function of pulse length or modulation bandwidth. Azimuth... 

The bandwidth is seen to vary from 500Hz to 22.2kHz. This is important in two respects. The first is that by no means all of the 150kHz modulation bandwidth is being used (in this case it is only 15% of the available bandwidth). Secondly, as the bandwidth is a function of time the performance of the radar system will also be a function of time. 

Troy L. Hacker, Performance Analysis of a Space-Based GMTI Radar System Using Separated Spacecraft Interferometry MS Thesis, Department of Aeronautics and Astronautics Massachusetts Institute of Technology, Lexington, MA, May 2000. 

A radar system is a way of viewing a scene using electromagnetic radiation at wavelengths that can be processed using electronic equip-... 

In this first section we discuss the basic ideas in a pulse-Doppler radar system. Our treatment is brief and focuses on the underlying theory rather than on the important issues of implementation. 

Illumination of the scene is provided by a signal that is emitted from the radar system. This signal is usually a waveform that is relatively slowly varying superimposed on a rapidly oscillating sinusoidal carrier. Thus it can be expressed as... 

Artis, Jean-Paul Henrio, Jean-Frangois Automotive Radar Development Methodology, International Conference on Radar Systems, Brest, France, 1999. 

Rohling, Hermann Meinecke, Marc-Michael Mende, Ralph A 11 GHz Automotive Radar System for AICC Applications, International Conference on Microwaves and Radar, MIKON98, Workshop, Krakow/ Poland, 1998. 

Raceway aquaculture systems, 3 193-194 Rack plating, 9 768 Ractopamine, 13 2, 14, 16 Radappertization, 3 655 Radar systems, vitreous silica in, 22 442 Radialene, 21 144 Radial flow impellers, 16 673, 684 flooding with, 16 701... 

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