VLF ENVELOPE TIMING EXPERIMENT.
Final engineering rept.
ITT FEDERAL LABS NUTLEY N J
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Experimental equipment was developed which measures the arrival time of a pulsed VLF radio wave to high resolution. An experiment was performed wherein the NBA naval radio station-generated VLF signal envelope was measured at Richmond, Florida, Washington, D. C. and Nutley, New Jersey, in order to transfer time from NBA to the experimental location. A rubidium frequency standard was flown successfully between the data gathering sites and NBA to correlate the time determined by the experiment with time as transmitted by NBA. The results achieved were best for the Nutley site where the total scatter of time determinations for the final week of the experiment was contained within limiting values of -50 to or -150 microseconds with respect to time as obtained by the transport. Results achieved at Washington and Richmond showed more scatter and additionally an apparent offset from the predicted values which might be caused by improper propagation delay assumptions or calculations. Analysis of 1000 single time determinations which are averaged to produce each time measurement indicate normal distribution patterns with a probable error of the average in the 10 to 15 microsecond area. This short term equipment resolution is encouraging since it implies random signal perturbation by noise and justifies the system technique for short term measurement. Author
- Non-Radio Communications