III. 2. 3 Determination of vertically attitude, 
Verticality may be required in absolute sense, e„g. to keep camera axis perpendicular to 
the geoid, or, to define the nadir point; or it may be required in relative sense, e.g. to 
record differences in camera axes between exposure stations. 
In the first category are used 
- Level bubble - 
- Vertical gyro for nadir recording - 
- Vertical gyro-controlled camera mount - 
- Inertial-controlled camera mount - 
In the second category are used 
- Horizon camera - 
- Solar periscope - 
- Inertial attitude-recording - 
Performance of elements. 
Element 
number 
Description 
Random standard 
errors in angular 
values 
ATT 1 
Direction of gravity acceleration as measured at any 
moment in survey flight (influenced by all aircraft 
movements to a resultant of all acceleration forces). 
approx. 1& 
ATT 2 
Direction of gravity acceleration integrated over a 
depending on 
longer period of time in near-straight and near-level 
circumstances, 
survey flight. 
approx. 20° 
ATT 3 
Inertial rigidity of mass movement in space 
= 
ATT 4 
Change of gravity direction with respect to inertial 
depending on speed 
space, when displacing the aircraft over the globe 
and direction. 
ATT 5 
Change of gravity direction with respect to inertial 
15 mins, of angle 
space, through earth rotation. 
per min. of time 
ATT 6 
External influences of friction and of torque drive 
on gyros. 
variable 
ATT 7 
Horizon recognition or: visibility to any distant 
object (through haze), 
variable 
ATT 8 
Solar altitude and azimuth per latitude and 
extremely high 
longitude and time 
accuracy 
ATT 9 
Attitude properties of the earth pendulum 
=