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99 
MEETING HELD ON WEDNESDAY, 14th SEPTEMBER, 1960 
In the Chair: Mr J. CRUSET, President 
Communication of Prof Konshin: 
the Element of Absolute Orientation Obtained during Flight 
In my communication today I should like to 
deal with the element of absolute orientation 
obtained during flight. This question is con- 
sidered of very great importance in the Soviet 
Union. 
In view of the shortage of time, I trust that 
you will permit me to ask the interpreter to 
read the translation of the communication. 
The main trend in the advance of aerial pho- 
tography in the U SS R is aimed at dispensing 
as much as possible with laborious photographic 
and geodetic ground work. As a result topogra- 
phic maps are produced mainly by photogram- 
metric means. One of the essential steps in this 
process is the development of aerial triangu- 
lation. 
The number of photographs included in the 
photogrammetric network depends on the way 
in which errors are accumulating and on the 
accuracy of the photograph itself. Therefore, in 
order to increase the number of photographs to 
be included in the photogrammetric network 
without a deterioration of its accuracy, it is ne- 
cessary to ensure a slower rate of error accumu- 
lation. 
This is possible provided the elements of ab- 
solute orientation are known beforehand. At 
present several techniques are used in the 
USSR, which make possible the determination 
of the elements of absolute orientation during 
flight. These include: 
a. the determination of differences in flight 
altitude statoscope indication: 
b. the determination on the scale of the pho- 
tograph by radio altimeter readings; 
c. the determination of the plane co-ordina- 
tes of the camera position by radio geodetic 
data and 
d. the elimination of the tilt effect in the 
photograph through the use of gyroscopic de- 
vices. 
The liquid or analogue type statoscope en- 
sures the determination of the flight altitude 
difference with a mean error of about plus/ 
minus 1 metre. A radio altimeter shows the de- 
termination of the aircraft’s flight altitude with 
à mean error of plus/minus 1.2 metres. Radio 
geodetic stations operating on the principle of 
Archives 4 
of phase difference measurements enable us to 
determine the plane co-odinates of the aircraft 
with a mean error of plus/minus 5 metres. The 
gyrostabiliser makes possible the obtaining of 
aerial photographs with an average tilt angle of 
plus/minus 10 degrees. 
At present two methods of using the 
elements of absolute orientation obtained during 
flight are employed. One is to use the data di- 
rectly. The other involves simultaneous adjust- 
ment between the values obtained and the va- 
lues determined photogrammetrically. Obvious- 
ly the higher the degree of accuracy in recording 
the elements of absolute orientation the greater 
the reason for applying the first method. On 
the other hand, if the photogrammetric measure- 
ments have a high degree of accuracy and the 
errors in recording are considerable, the second 
method is, of course, preferable. 
For making photographic maps on the one to 
a hundred thousand scale, the cameras are 
mounted in a gyrostabiliser, the statoscope and 
radio altimeter readings being recorded at the 
moment of exposure. The aerial photographs 
are taken with cameras of 55 millimetre or 70 
millimetre focal lengths on a scale of 1 to 
70,000 to 1 to 100,000. 
Beside the main strips additional strips at 
right angles to them are flown every 100 kilo- 
metres, while recording radio altimeter and 
statoscope data as well as radio geodetic station 
data. Ground control consists of plane co-or- 
dinates of ground stations. In addition, on 
transverse flights the geodetic altitude of 4 points 
is determined at intervals of 50 to 60 kilometres 
in the stereo pair. The obtained data makes pos- 
sible the determination of the plane co-ordinates 
of the projection centres of the photograph of 
the transverse flights, and the height of the nadir 
points of the main and transverse strip flights; 
aerial triangulation follows. 
Other mapping processes remain unchanged, 
but are considerably simplified by the small tilt 
of the exposure. When making maps of the scale 
of 1 to 25,000 to 1 to 50,000 it is advisable to 
adjust the photogrammetric data and the radio 
data simultaneously. Aerial cameras of various 
angles are used in accordance with the terrain; 
from focal lengths 55 millimetres, that is