3- Minimizing influences due to aircraft movement 
Only two of the movement components have a significant 
effect on image quality: forward motion of the aircraft, 
and angular oscillations excited mainly by air turbulences. 
The influence of forward motion is known, and the use of 
aerial survey cameras without forward motion compensation 
(FMC) is declining. Due to the angular motions, photogra 
phic system with FMC (such as LMK, MKF-6, and MSK-4) cannot 
yet completely dispense with a limitation of the long 
exposure times. This limitation, however, is subject to 
factors differing from those limiting forward movement. For 
identical angular motions, it is independent of the flying 
height. The effect of angular aircraft oscillations on the 
image data has bean analysed according to /3/. 
The typical angular motion frequencies having the highest 
effect on the image range from 0.1 to 1 Hz; the amplitudes 
of their angular velocities exhibit a significant depen 
dence on turbulence. Under smooth flying conditions (with 
out noticeable turbulences), the roll motion of aircraft 
with take-off weights of 3...6 t and without autopilot 
system reaches angular velocity amplitudes of up to l°/s, 
while in the presence of medium-scale turbulences the maxi 
mum is 4 °/s. The pitch and yaw amplitudes are 20... 30 */. of 
the above values. 
Fig. 1: 
Determination of the 
total image point mo 
tion for different ima 
ge coordinates. 
Example: LHK-15 at 
medium turbulence = 
3 ° /s, Ï = * = l°/5l 
and shutter speed t fi = 
1/350 s, or mith scar 
cely noticable turbu 
lence (w* 1°/e, *î°=3c“= 
0,4*75 and t 8 = 1/120 s; 
drift has been compen 
sated i .e. <#0 - 0° ; 
cf ,Û?,¿maxima in phase; 
co in the image repre 
sents A bUùj) etc. 
The figures are amounts 
of image motion in /im . 
Locations in the image 
frame are designated 
according to orienta 
tion in the aircraft. 
Contrary to roll the other angular components, pitch and 
yaw, add only about 25 '/. to the maximum 
Depending on the phase relation of the 
nents produces a maximum of image point 
least at one point at the frame edge of 
of the four corners. An example of this 
total image motion. 
individual compo- 
motion (bluring) at 
the image or at one 
is shown in Fig. 1,