Evaluation and demonstration of a new post-disaster Em communication technique for mines.
NTIS: PB/82-143181, 1981; :1-101
The objective of this report was to quantitatively compare an existing emergency mine communication system with a proposed automated system that features extended signal processing and a novel signal. A new post-disaster system, intended to use through-the-earth em propagation, was demonstrated at input signal-to-noise ratio (snr) of -34 db. The system presently available requires an input snr of +6, and uses a human ear detector. The present work demonstrated coherent integration for the automated system in multiples of 17 seconds, up to 1,088 seconds (18 minutes). A repeating pseudorandom (or pseudonoise) signal is used that offers an ideal autocorrelation at the receiver matched-filter output. A novel decision-variable algorithm achieves the estimate of noise level by using those matched-filter output samples that occur between the signal autocorrelation peaks.
Mining-industry; Emergency-response; Communication-systems; Quantitative-analysis; Signaling-systems; Noise
CP; Final Contract Report
NTIS Accession No.
University of Michigan