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Description and availability of airborne Doppler radar dataAn airborne, forward-looking, pulse, Doppler radar has been developed in conjunction with the joint FAA/NASA Wind Shear Program. This radar represents a first in an emerging technology. The radar was developed to assess the applicability of an airborne radar to detect low altitude hazardous wind shears for civil aviation applications. Such a radar must be capable of looking down into the ground clutter environment and extracting wind estimates from relatively low reflectivity weather targets. These weather targets often have reflectivities several orders of magnitude lower than the surrounding ground clutter. The NASA radar design incorporates numerous technological and engineering achievements in order to accomplish this task. The basic R/T unit evolved from a standard Collins 708 weather radar, which supports specific pulse widths of 1-7 microns and Pulse Repetition Frequencies (PRF) of less than 1-10 kHz. It was modified to allow for the output of the first IF signal, which fed a NASA developed receiver/detector subsystem. The NASA receiver incorporated a distributed, high-speed digital attenuator, producing a range bin to range bin automatic gain control system with 65 dB of dynamic range. Using group speed information supplied by the aircraft's navigation system, the radar signal is frequency demodulated back to base band (zero Doppler relative to stationary ground). The In-phase & Quadrature-phase (I/Q) components of the measured voltage signal are then digitized by a 12-bit A-D converter (producing an additional 36 dB of dynamic range). The raw I/Q signal for each range bin is then recorded (along with the current radar & aircraft state parameters) by a high-speed Kodak tape recorder.
Document ID
19940015946
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Harrah, S. D.
(NASA Langley Research Center Hampton, VA, United States)
Bracalente, E. M.
(NASA Langley Research Center Hampton, VA, United States)
Schaffner, P. R.
(NASA Langley Research Center Hampton, VA, United States)
Baxa, E. G.
(Clemson Univ. SC., United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1993
Publication Information
Publication: JPL, Progress In Electromagnetics Research Symposium (PIERS)
Subject Category
Communications And Radar
Accession Number
94N20419
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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