Global Reference Atmosphere

Block Global Reference Atmosphere implements a digital model of the global reference atmosphere according to GOST R 53460-2009. For the specified geopotential altitude and month, the block determines the average latitude values of temperature, air pressure and density, the speed of sound, and, if necessary, wind parameters.

The model supports height ranges from 0 before 30 km and from 0 before 120 km. In the range of 0 before 30 km can take into account the set random deviations of atmospheric parameters and choose the method of their mutual redefinition. If accounting for random deviations is disabled, the block returns the average tabular values.

The parameter values are calculated according to the GOST tables using linear interpolation method «Linear point-slope». For longitude interpolation, the midpoints of the tabular ranges are used as reference points.: −150, −90, −30, 30, 90 and 150°. Therefore, on the border of adjacent ranges, the result is the average of the corresponding tabular values. The longitude can be set in one of two ranges: from −180 before 180° or from 0 before 360°. In the first case, negative values correspond to the western longitude, and positive values correspond to the eastern longitude. Values are higher 180° the unit converts to equivalent values the range from −180 before 180°, for example 270° — in −90°. Values outside the specified ranges are not allowed.

If the value of the argument exceeds the boundaries of the tabular data, the extrapolation method is used. «Clip»: the block returns the value at the nearest border of the table. In particular, the GOST tables contain data for latitudes from −80 before 80°, therefore, for latitudes below −80° values are used for −80°, and for latitudes above 80° — values for 80°.