Radio Refractometer for High Resolution Gradient and Turbulence Measurements of Atmospheric Refractive Index.

Period of Performance: 05/01/2000 - 01/02/2001


Phase 1 SBIR

Recipient Firm

Quadrant Engineering, Inc.
107 Sunderland Road
Amherst, MA 01002
Principal Investigator

Research Topics


This Phase I SBIR proposal seeks support to design and construct arevolutionary compact, versatile, radio refractometer system. Therefractometer will be capable of accurately (better than 0.5 ppm)sensing atmospheric refractive index gradients and turbulentfluctuations at sufficiently small scales so that it can be used tovalidate signal propagation models which are used/proposed to predictperformance of a variety of VHF, UHF and microwave communications andremote sensing systems. Modern solid state RF and signal processingelectronics will be used to activate a sensing cavity, to processits output signal and to display atmospheric refractive index fluctuationsin real time. The sensing cavity will be designed using a low cost,high stability material, such as electroplated ceramic. To minimizethe adverse and uncertain effects of turbulence at high air speeds,the sensing cavity will be designed for enclosure in a flowcontrolling aerodynamic housing. Comparative test and evaluation ofthe prototype instrument will be done using critical components from aThompson-Vetter laboratory standard refractometer. Calibration andfield testing will be performed at the comprehensive "Rock Springs"micrometeorological/turbulence field site operated by the Departmentof Meteorology at Penn State University. Current research programs in atmosphericturbulence utilizing clear-air radar systems require reliable in-situprobing systems for validation of radar-derived atmosphericparameters. At present, there are no modern refractometersavailable to support such programs.