Topcon GPT-2000 用户手册

 

   13 CORRECTION FOR REFRACTION AND EARTH CURVATURE

 

13-1

 

The instrument measures distance, taking into account correction for refraction and earth curvature.

 

Distance Calculation Formula; with correction for refraction and earth curvature taken into account. 
Follow the Formula below for converting horizontal and vertical distances.

Horizontal distance  D = AC(

 

α

 

) or BE(

 

β

 

)

Vertical distance Z =BC(

 

α

 

) or EA(

 

β

 

)

D = L{cos

 

α

 

–(2

 

θ

 

 – 

 

γ

 

 ) sin

 

α

 

}

Z = L{sin

 

α

 

+(

 

θ

 

 – 

 

γ

 

 ) cos

 

α

 

}

 

θ

 

 = L.cos

 

α

 

/2R........... Earth curvature 

correcting item

 

γ

 

 =K

 

•

 

Lcos

 

α

 

/2R.......

Atmospheric
refraction 
correcting item

K =0.14 or 0.2.......... Coefficient of 

refraction

R =6372km.............. Radius of earth

 

α

 

  ( or 

 

β

 

)................... Altitude angle

L .............................. Slope distance

 

●

 

The conversion formula for horizontal and vertical distances is as follows when correction for 
refraction and earth  curvature is not applied.
D=L

 

•

 

cos

 

α

Z=L

•

sin

α

Note:

The coefficient of the instrument has been set at 0.14 before shipment (K=0.14). 
if the "K" value is to be changed, refer to 16 “SELECTING MODE”.