Commission II Presented paper 
Soviet Stereophotogrammetric Instruments 
by Prof. F. V. DROBYSHEV 
U.S.S.R. 
The high rate of development of the national economy of the U.S.S.R. and the research 
and prospecting work connected therewith, that is being carried out in large volume in 
every part of our immense territory, have resulted in rapid development and perfection of 
aerial survey in the Soviet Union. The principal attention has been directed to improving 
| the stereophotogrammetric method of mapping as giving a possibility to considerably reduce 
the volume of field geodetic and topographic work. This possibility was extremely important 
for mapping nearly-inaccessible regions, and especially those where the field season is of 
short duration. Particular attention has been paid to utilizing nearly-vertical aerial photo- 
| graphs, i.e. such, that are taken with low angles of deviation from the vertical. Aerial photo- 
| graphs of this kind secured the highest precision of the work accomplished with the aid of 
quite simple photogrammetric instruments created at that time. As a result, such simple 
but very precise and efficient stereophotogrammetric instruments appeared as the topo- 
graphic stereometers which are still in wide use. 
However, the nearly-vertical aerial surveying with cameras having the angular field 
of the lens about 60°, was not efficient. Low altitudes of flight necessitated increasing the 
volume of aerial photography and that of the office photogrammetric work; the accuracy 
of obtained photogrammetric networks was not high owing to increased number of sections 
in a net of a given length; therefore it was necessary to increase the number of ground 
control points, i.e. to augment the volume of field work. But, on the other hand, increased 
flight altitudes resulted in diminished precision of stereophotogrammetric mapping of 
relief. Therefore the problem was raised of creating wide-angle camera lenses that would 
retain all advantages of vertical aerial surveying, and at the same time would guarantee 
high economic efficiency. 
It was already in 1934 that, under the direction of M.M. Rousinov, a wide-angle 
(28 — 100^) aerial camera lens was designed. A little later (1936-1937) more perfect lenses 
of the same angular field appeared, and in 1939 M. M. Rousinov designed the lens Russar-29 
with an angular field 122^; this type of lens has remained the one most widely used till 
now. At present, aerial mapping in U.S.S.R. is effectuated also with cameras having the 
angular field of the lens equal to 133°; and in certain special cases are used lenses of 
angular field as wide as about 150°. 
At present, stereoplotting from obtained aerial pictures is done in topographic stereo- 
meters which still keep their importance, especially for mapping flat and hilly regions: 
— Soviet multiplexes with wide-angle (2f = 100°) and super-wide-angle (25 — 122^) 
projection camera lenses were created; 
— Methods were elaborated that utilize universal instruments (the stereoplanigraph 
and the multiplex) for plotting from photographs by means of transformation of bundles 
of projecting rays; 
— Universal stereophotogrammetric instruments of a new type were designed, which 
give a rigorous solution of the problem of identification terrain points from photographs 
that have been taken with any wide-angle lens under utilization of the principle of ray- 
\ bundles transformation. 
Here are to be mentioned theoretical investigations of the problem of photogrammetric 
model plotting with utilization of transformed bundles of projecting rays carried out by 
Prof. M. D. Konshin, Prof. A. N. Lobanov, the corresponding member of the Academy of 
Sciences of the U.S.S.R. Prof. N. G. Kell, and Prof. G. V. Romanovsky. The most general 
treatment of the problem was given, however, in theoretical investigations of the can-