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A new data acquisition concept for digital ionosondes: Phase‐based echo recognition and real‐time parameter estimation
Author(s) -
Wright J. W.,
Pitteway M. L. V.
Publication year - 1999
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/1999rs900039
Subject(s) - computer science , amplitude , echo (communications protocol) , sampling (signal processing) , data acquisition , depth sounding , phase (matter) , algorithm , acoustics , geology , telecommunications , optics , physics , detector , computer network , oceanography , quantum mechanics , operating system
The problem of identifying echoes in digital ionosonde observations is discussed, starting with an off‐line simulation of the procedure long used in real time by the dynasonde. In that method, echoes are defined as amplitude‐modulus peaks from rapid (10‐μs) sampling of receiver quadrature outputs; coincidence of peak time among a small number (4–8) of repeated pulses has served well to reject impulsive noise while deciding the complex‐amplitude samples to be retained for off‐line analyses. This paper presents a new method of echo recognition dependent on all of the phase information contained in the same rapid sampling. No change is made in basic sounding function, but conversion to physical parameters is done first, for all 10‐μs samples; the consistency of these parameters in five dimensions over four or more samples defines an echo, or at least a partial “glint.” In an example recording, the new method recognizes about 60% more echoes and glints, giving better trace continuity than the earlier method. Measurement resolution among proximate echoing regions is improved. Weighted means of the physical parameters within their defining samples yields better accuracy. Almost incidentally, these results would be available immediately in a real‐time implementation of the method.