340 



REFRACTION AND REFRACTIVE INDEX MODELS 



45 



en 



40 - 



35 



30 



210 



250 



350 



400 



Figure 8.18. Total range error at do equals 50 mrad, h equals 70 km, for the CRPL 



standard sample. 



of the coefficients in (8.18) and (8.22) and to predict these values in ad- 

 vance by analysis of a large heterogeneous sample of refractive index 

 profiles. In the succeeding subsections it will be shown how this has 

 been done, and a comparison will be made between the results so derived 

 and the results of some measurements over actual radio paths. 



8.3.3. The CRPL Standard Atmospheric Radio 

 Refractive Index Profile Sample 



In the preceding section it was shown that, theoretically, it should be 

 possible to estimate either radar elevation angle errors or radio range 

 errors at any particular location by means of a system of linear equations 

 in N s, where the coefficients are functions of the target position. The 

 target position can be specified by either the apparent elevation angle and 

 target height, or the apparent range and target height (or as a third possi- 

 bility, the apparent range and elevation angle), each having advantages 

 in different situations [19]. The equations recommended are 



= ai (00, hi) + bi {do, ht) Ns ± S.E.i {do, he), 



(8.23) 



