Measuring small propagation frequency shifts and fluctuations by phase to avoid cross-correlation errors

摘要

This paper investigates the practicality of measuring microhertz to millihertz frequency differences by phase differences using an off-the-shelf SDR receiver. The phase difference method is two orders of magnitude faster if the phase can be measured to 3.6^{0. The method has been used to confirm the discovery of a 16.2 (±1) μHz red-shift of the frequency over a 190 km ground wave path. The estimate by extrapolation from previous ionospheric HF measurements is 15-20 μHz on a transmitter absolute frequency error of ~1 mHz. The mechanism now assumed is that the frequency red-shift is proportional to the curvature angle of the path, and also proportional to the square root of frequency. The new Propagation-Phase/Frequency-Shift (PPFS) theory is now being analysed using a new Coupling-Graph technique. It is based on the `Filamentary Model of Electromagnetism' originally announced in 2011. It further supports the concept of EM detection and generation of gravity-potential-waves. The phase-difference method is found to be impervious self- and cross-correlation random `spurs' and `spectrum-collapse' that can bedevil phase noise measurements.}