Home » Volume 9 / 2005 » Issue 3 »
Multipath Interference Mitigation for Cotton Bale Microwave Moisture Sensing
Matthew G. Pelletier
Full Text PDF (526K)
Previous research indicated that the effects of multi-path interference on a microwave cotton moisture sensor are significant enough to force a completely new calibration for each and every installation, which is an expensive and time-consuming task. This research was conducted to determine if a system could be designed that would be impervious to multi-path interference. The feasibility of using swept frequency modulation for isolation of the direct free-space signal from the multi-path interference signals was examined through a simulation analysis. The analysis focuses on near range reflectors that are typical in cotton gin applications as opposed to far range reflectors that are common in the telecommunications industry. The results of the analysis indicate the proposed technique provides a 37 dB improvement for multi-path rejection over current techniques.