A method for grading evaluation of the atmospheric refraction effect on the radio marginalline-of-sight distance

Different atmospheric refraction conditions could affect the radio marginal line-of-sight (LoS) distance and the scope of operation of radio system significantly. For vast number of radio system users to understand and use the standards of radio marginal LoS distance more intuitively, this paper presents a grading evaluation method based on the radio line-of-sight index as characterization factor, according to the degree and probability of radio marginal LoS distance deviating from the standard line-of-sight. On the basis of this, the possible influence of the radio line-of-sight index of different levels on the radio system is analyzed, as well as the influence of atmospheric refraction on the radio line-of-sight is described intuitively. This paper gives the distribution of the percentage of time of near ground the radio line-of-sight index in China.