FIELD: radio engineering.
SUBSTANCE: available method to assess noise immunity of board radio electronic devices (BRED) of communication and navigation, including measurements; the minimum ratio of signal capacities to noise at the input of the receiving device BRED 
from sources of a signal and noise placed on the ground at the required distances (
,
), which ensure normal functioning as intended, differs by the fact that measurements of the minimum ratio of signal capacity to noise capacity at the inlet of the receiving device BRED 
at which normal functioning as intended is provided, from sources of signal and noise are carried out on a measurement site, and distances from sources of noise and signals to BRED must have the following ratio: 
(1), at the same time the measurement site and sources of signals, noise and BRED installed on it must meet the following conditions: 
(2), where r13, - distances of communication for surface and air experiments accordingly; r23, 
- distances of suppression for surface and air experiments accordingly; h1, h2, h3 - heights of antennas lifting on the measurement site of signal and noise sources and BRED accordingly; a - the attenuation ratio in atmosphere; FVH, FVG - a module and a phase of a complex Fresnel reflection coefficient for vertical and horizontal polarisation; r0 - distance of direct visibility; λ - wave length.
EFFECT: higher accuracy of measurement of noise immunity of board radio electronic facilities of communication and navigation at simultaneous simplification of its technical implementation due to replacement of a flight experiment with a surface experiment.
2 dwg
