Fig. 9) 
fixed point A 
ey, = @ —e 
4 2, 2% 
e, =e —e 
1 14 ly 
| — Sin a cos f) 
— sin f 
im we get 
  
Example‘ 
X = y = 8 cm; 
p, = 0,05 mm 
: 3x = dy 10,5 u 
the projection plane with 
€ = 11,5 cm; 
and IM 
1=3 
  
x = 0Y = 0,03 mm. 
For the gimbal axis in the pro- 
in centre the primary axis is 
  
| 
jet y 2 | | ; 
"uid to x and the projection er- | E 7 = w 
" jx and ôyc are given with equa- | | | | 
Kons (1). l : | 
s x the gimbal axis below the p Lll 2 | 
mjection centre the primary axis is tom FE == 
parallel to y and the projection errors | | |. | 
| | 
i and öy? are given with equations | 
I 
| | | I | 
(la). : | D. | fiz 25 | | 
The total projection error will be, | Eq mea "uei 
imsidering equations (1), (la), (2) 
and (9) ra 
0X =ndxa + (n + 1) àxe + óxb 
óY = ndy2 + (n + 1) öyc + öyp (10) 
  
Conclusions : 
The diagnosis will be, if a 9- or better 25-point grid measurement results in 
ı) fig. 7, 8 or 9: errors in the gimbal axis in the projection centre. (The Stereosimplex 
Ill provides good possibilities for an adjustment. That should be made, however, only 
by a specialist of the factory); 
i) fig. 7,8 or 9, all rotated for 1002: errors in the gimbal axis below the projection centre; 
() similar graphs, based on equations (9), could be drawn for errors in the gimbal axis 
shove the projection centre. 
Fig. 21 ean be used for a check of the interchanging of the distortion cams with 
tt toe, Assume a 25-point grid measurement is made with the spherical cam show- 
igo projection errors. We change the distortion cam. If a 25-point measurement results 
uy, after having subtracted the values due to the distortion, in fig. 21, we know that the 
an is not in its proper position in the vertical direction (e,!). Cleaning of the cam and 
is support may help. 
t) Potvilliers Stéréotopographe Type DC. 
Both the gimbal axes in the projection centre (c), and above the projection centre (a), 
tae the primary axis parallel to y; the corresponding projection errors are given with 
tations (1a). The gimbal axis below the projection centre (b) has the primary axis 
arallel to x; the projection error is given with equations (1). The total projection error is 
0X = (n + 1) 6x¢ + n óxa + óxb 
0Y = (n + 1) dy + n öya + dy. 
Conclusions : 
[fa 9. or better a 20-point measurement results in the graphs 7, 8 or 9 the analysis 
"IL errors *» €9 or e, in the gimbal axis below the projection centre. If the same 
caps, but rotated for 100g are obtained, the diagnosis will be errors 65, €9 Or e, in either 
le tiia axis in the projection centre, or above the projection centre, or in both of them. 
  
  
  
  
  
  
  
  
  
  
  
  
  
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