Preliminary Radar Performance Data on Passive Rocket-Borne Wind Sensors

Rocket vehicles are being used to expel passive wind sensors in the altitude range of 100,000 to 300,000 feet. The sensors are tracked with S-band and X-band radars to determine wind direction and velocity. Both chaff and metalized parachutes serve as wind sensors and AGC voltage recordings made on both X-band and S-band radars during tracking periods are presented. The recordings are calibrated in decibels above the radar minimum discernible signal and plotted vs slant range. A short discussion of the effects of chaff dispersion is included. Although chaff dispersion deteriorates the effectiveness of the target at a rate of about 20 db/hour, it is concluded that the effective radar target size of the sensors and the slant ranges over which they are employed are quite compatible when AN/MPQ-12 and AN/MPQ-18 radars are utilized.