Abstract
An acoustical estimator for gas temperature distributions is proposed. It is based on the MAP (Maximum A Posteriori) estimation with local iterations that is referring acoustic time-of-flight through non-linear observation process. The system is also featured a matched filter with complex absolute detection that is free from unknown phase shift. In addition, for fast measurement, the Gold sequence P.R.K. (Phase Reversal Keying), which has sharp autocorrelations and low cross-correlations, is applied to the acoustic signal for simultaneous time-of-flight identifications on paths. It has been shown to effectively estimate the temperature distributions in a gymnasium and outdoor fields. The estimator has been applied to evaluation of watering effect.
