A high range resolution 9.4/18.8 GHz harmonic radar for bees searching

This paper demonstrates a 9.4/18.8 GHz harmonic radar for bee searching to investigate the phenomenon of colony collapse disorder (CCD). The radar system transmits a pulsed coarse/acquisition code (C/A code) signal with 0° and 90° shift key modulation and then receives the C/A code signal from transponders attached on the bees in BPSK modulation. Using the technique of C/A code positioning, a distance resolution of 0.15 m is achieved. The transponders are designed to minimize the effect from the bodies of bees. The outdoor experiments indicate the sensitivity of the radar system to be −95 dBm and with the distance of 65 m with 6-W peak power. With 3-kW peak power, the distance at which the bees can be located is expected to be 450 m.