折射率公式对电波折射修正精度的限制

The limitation of the refractive formulas on precision of radiowave refraction correction

电波折射误差修正精度主要取决于大气折射率剖面精度 ,而大气折射率是由温度、气压和湿度通过计算得到的。计算大气折射率的公式有两种 ,一种为常用公式 ,另一种为改进型公式。由于两种公式是由统计得到的 ,因此存在一定的误差。假设大气参数的测量是准确的 ,则经过对两种公式误差引起电波折射误差的计算可知 ,如果要求距离折射误差精度小于 0 .1m ,则常用大气折射率计算公式不实用 ,最好采用改进型折射率计算公式 ,如果要求距离折射误差精度为 0 .3m ,则常用大气折射率计算公式可以使用。如果采用精度较差的 5 9型探空仪测量大气参数 。

The precision of radio wave refractive error correction mainly deperds on that of atmospheric refractive profile, and the atmospheric refractivity is calculated by using temperature, air pressure and humidity. There are two formulas in general. One is common formula, and the other is improved formula. There are some error in them because of the statistical calculating needed for the two formulas. Hypothesize the measurement of the atmospheric coeefficients are accurate, then by colculating the radio wave refractive error resulted from the two formulas′ error, we get to know that when range refractive error is required to be less than 0.1m, we had better adop the improved refractivity formula instead of common formula for its impracticability. When range refractive error is required to be 0.3m, we can use the common formula to calculate the atmospheric refractivity. If the atmospheric coefficients are measured by 59 model sounding application which has a poorer precision, the atmospheric refractive profile can be calculated just by using common formula.