The description of the National primary standard for the unit of average laser radiation power GET 28-2016 with a power range from 10–9 to 5·10–3 W is described. The principle of operation of a standard based on a photoelectric trap detector in the range from 10–9 to 5·10–3 W is described. As a result of metrological studies at National primary standard, it was determined that the value of the total standard uncertainty of reproduction and transmission of an average power unit for the range from 10–9 to 5·10–3 W is no more than 0.36 %. The model and theoretical characteristics of the measuring beam splitter, allowing to expand the range of the National primary standard to the range of kilowatt power levels, are presented. National primary standard allows solving the problems of metrological support of promising low-level laser ranging systems both in the ground and in the aerospace field, ensuring the uniformity of measurements of radiometric parameters of low-intensity laser radiation fluxes.
