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This working group meeting discusses the scan characteristics and design considerations for space-based lidar systems using holographic receivers. Topics include scan elevation angles, adjustable scans, scan patterns, axis of scanning, slew rate, and rotating single HOE conical scanner design.
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Geary Schwemmer Meeting of the Working Group on Space-based Lidar Winds Bar Harbor, Maine June 23 – 25, 2003 Work supported by: IPO & NASA Scanning Strategies for Holographic Receivers
Scan Characteristics • Scan elevation angle (relative to nadir) • 40-50° optimum? • Adjustable? • Number of azimuth look-angles relative to S/C • continuous vs step and stare • Repeating pattern vs targeted observations • 1 or 2 axis? • Slew rate
Rotating single HOE conical scanner Design proven with ground-based and airborne instruments Mechanically simple: static focal plane optics with single FOV Requires reaction wheel or spinning S/C Infinite variety of look angles Difficult to adjust elevation angle SHared Aperture Diffractive Optical Element Still in the laboratory Lowest Inertia: minor or no moving parts Limited number of HOEs (look angles): ~5 Perfect for “step and stare” scanning – instant slewing Easy to implement multiple lasers and imaging 2-D detector arrays (focal plane scanning 5-7°) Holographic Scan Schemes