DESIGN OF A BISTATIC DUAL-DOPPLER RADAR FOR RETRIEVING VECTOR WINDS USING ONE TRANSMITTER AND A REMOTE LOW-GAIN PASSIVE RECEIVER

A bistatic dual-Doppler network consisting of an existing single trans mitting pencil-beam weather radar and a remotely located, nontransmitt ing, passive bistatic, receiver with a low-gain antenna was constructe d and tested during 1993. High-quality dual-Doppler vector winds were retrieved from this system. The windfields were compared to those coll ected with a traditional two-transmitter dual-Doppler system. Several interesting engineering challenges relating to frequency and timing sy nchronization were resolved in order to retrieve successfully Doppler velocities at a remote bistatic site. Frequency synchronization was ac hieved by using extremely stable local oscillators, linked by both Glo bal Positioning Satellite (GPS) signals and transmitter sidelobe coupl ing. Both methods provided the necessary one part in 10(9) coherence n ecessary for calculating accurate Doppler velocities. Timing/gating sy nchronization with submicrosecond accuracy was achieved by using local oscillators at each site linked with GPS and sidelobe coupling. The s uccessful test of this system demonstrates that inexpensive and practi cal bistatic multiple-Doppler networks can be deployed. These systems can provide three-dimensional vector winds for a number of purposes in research, aviation, media, weather prediction, education, meteorologi cal modeling, and severe weather detection.