COMPARISON WITH EXPERIMENTAL RESULTS 



349 



Figure 8.23 shows the results of a comparison between predictions of 

 elevation angle errors estimated from the CRPL Standard Sample and 

 some measurements made with a 6-cm radar at Tularosa Basin, N. Mex. 

 [21]. Each point represents the mean of five "instantaneous" readings 

 made at 1-min intervals over a period of 4 min. The standard deviation 

 of each five-reading group averaged 0.16 mrad, and the maximum range 

 in any one group was 0.58 mrad. The radio energy was propagated over 

 a 45-mi path at a mean apparent elevation angle of 18 mrad; the target 

 was a beacon located on a mountain peak 5610.5 ft higher than the desert 

 floor where the radar was located. The data in figure 8. 18 show that even 

 for this rather extreme case, where the degree of correlation between N s 

 and € is expected to be only 0.4, agreement is obtained between: 



(a) the predicted and observed mean refraction, 



(b) the observed and predicted slopes of the e versus N s relation, and 



(c) the observed and predicted residual errors of predicting e from N s 

 alone. 



O 



a: 

 o 

 cr 



or 



< 



O 



h- 

 < 

 > 



LaJ 



I I I \ 



TARGET HEIGHT=I7I km 

 RANGE -72.5 krn 

 MEAN APPARENT 

 ELEVATION ANGLE = 19.0 mrad 



STANDARD ERROR 

 h OF ESTIMATE 



\ \ \ 



PREDICTED FROM 

 ORP.L, STANDARD SAMPLE 

 6p=0OI02Ns-l,50 

 SE = + 0.608mrad 



OBSERVED REGRESSION: 

 eQ=O.OI03Ns-l.65 

 r=0 427 



STANDARD ERROR 

 OF ESTIMATE 







230 240 250 260 270 280 290 300 310 320 330 



Ns 



Figure 8.23. Measured refraction of C-band radar at Tidarosa Basin, N .Mex. 



