Project Title:

Low-Cost Doppler Micro-Radar Rain Gauge

08.02-1512
Low-Cost Doppler Micro-Radar Rain Gauge
Ophir Corporation
3190 S. Wadsworth Blvd., Suite 100
Lakewood, CO 80227
Loren D. Nelson  (303-986-1512)
GSFC -- NAS5-30285

Abstract:

	 New NASA satellite remote sensing programs such as the Tropical Rainfall Measuring
Project, which intend to measure global precipitation, require "ground truth" calibration.
The overall goal of this project is a practical and inexpensive precipitation gage
based on miniature, frequency-modulated, continuous-wave Doppler radar technology.
It would be suited to shipboard or land use.
	The Phase I effort was aimed determining which frequency band provided the best
overall characteristics for measuring rainfall. At X-band frequencies, conditions
for scattering are better met, and the water vapor in the atmosphere absorbs less.
On the other hand, droplet reflectivity is greater at K-band, making stronger Doppler
signals possible. Prototype equipment included both X-band and K-band transceivers
which permitted simultaneous observation of performance under identical environmental
conditions. Test results indicate that K-band offers the greatest overall advantages.
The stronger Doppler signal and lower error rate tip the scales in its favor.

Potential Commercial Application:

Potential Commercial Application: Commercial uses would be to measure rainfall at
sea in order to improve the National Weather Service data base and to support the
NASA Tropical Rainfall Measuring Project to measure droplet-size distributions, cloud
ceiling height at airports, and present weather conditions.