FIELD: measurement equipment.
SUBSTANCE: invention relates to the field of measurement equipment and may be used to measure level of liquid or loose materials, and also to measure distance. The invention concept is as follows: method to measure level of material in reservoir consists in the fact that inside zone with higher error of measurement caused by availability of interference reflector, formation of likelihood function logarithm (LFL) values is carried out, having multiextremal nature, and local extremum of LFL is found, corresponding to actual value of level, by variation of delay time of reference signal within the limits that correspond to two limits of measured level, which differ from value of level predicted by previous measured values, by not more than half of wave length of carrying oscillation towards both sides. In case of such formation of borders, one and the same extremum of LFL is continuously monitored, corresponding to actual status of medium level. Phase of reference signal for calculation of LFL is determined using previously measured phase-frequency characteristic of metering device, or is accepted as equal to phase of maximum spectral component of differential frequency signal calculated at the border of zone with higher error of measurement. Using produced value of delay time of reflected signal corresponding to maximum of LFL, distance to material surface is calculated. To determine borders of zones with higher error of measurement, preliminary practice is arranged, when position of all interference reflectors is determined on empty reservoir, and two borders of zones with higher error are specified in neighbourhood of each one, differing from distance to according interference reflector by tripled value of element of frequency modulated signal resolution with specified deviation of frequency.
EFFECT: increased accuracy of level measurement with availability of interference signals caused by reflections from elements of reservoir design.
11 cl, 6 dwg
