METHOD OF NAVIGATIONAL SURVEY OF PIPE LINES (VERSIONS) Russian patent published in 2002 - IPC

FIELD: inspection of extended pipe lines. SUBSTANCE: proposed method consists in passing tool inside pipe line; this tool is provided with sensors for navigational measurements, processing and storage of measurement data; navigational measurements are made with the air of sensors passed through pipe line; measurement data digitized and are recorded in storage; parameters of spatial position of pipe line are determined after passage of total according to stored data. In the course of passage of tool, digital conversion of measurement data is carried out; in the course of digital conversion, sequences corresponding to each sensor are separated. Increment in magnitude as compared with previous magnitude is calculated for magnitudes of sequence but for first magnitude in sequence at rule of numbering defined beforehand; then converted sequence is formed where first magnitude coincides with initial one and other magnitudes of converted sequence are replaced by respective increments in magnitudes. Change of magnitudes of converted sequence is performed through read-out of first "n" bits of respective calculated increment and record of n-bit increment obtained into converted sequence. Increment and does not exceed magnitude "j+2". Medium frequency of recording respective magnitudes in storage ranges from 70 to 300 Hz. For each sequence, average magnitude is calculated in sequence for magnitudes of sequence including one magnitude in sequence; increment in magnitude as compared with average magnitude is calculated; converted sequence whose magnitude in sequence corresponding to excluded magnitude is formed and is replaced by average magnitude in sequence; other magnitudes of converted sequence are replaced by respective increments of average. EFFECT: enhanced accuracy of measurements of axial misalignment of pipe lines from designed position and from positions determined during previous navigational survey. 29 cl, 7 dwg