the strip in X, Y or Z. The following table illustrates this 
approach. 
Table I 
  
Type of Auxiliary Height Control Horizontal 
Airborne Instruments Control 
  
LY wo bz Z  lecanel DC XY 
  
APR X x x 
Statoscope X 
Horizon Camera x x 
Solar Periscope X x 
Gyro Systems x x 
Inertial Guidance System x x x x 
Forward Looking Oblique 
Photography x 
Doppler Navigation x 
Aerodist, Shiraon, Hiran, 
Autotape, etc. x x 
ANQ-28 x x x x x x 
  
  
  
  
  
  
  
  
  
  
The relative importance of each of the above instruments 
depends to a large extent upon the requirements of the particular 
project. When one is concerned with individual strips one would 
look for auxiliary data which would permit a reduction in the 
density of horizontal, os well as vertical ground control. When 
large blocks are triangulated the auxiliary data which minimize 
horizontal ground control lose their importance because the 
latest techniques in horizontal block adjustment methods reduce 
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