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BALLISTIC PHOTOGRAMMETRY, SCHMID 47
tele. A similar lens of approximately 350 mm focal length and a maximum opening of
1 : 2.0 is presently under design, so that the BC-4 instrument may be optimized for the
task of measuring, with high precision, the directions to points on the orbits of satellites.
Such points will be signalized by short duration high intensity flashes. In addition, Dr.
Bertele designed the Super Astrotar for the purpose of recording faint light signals, oc-
curring with extreme object distances. The Super Astrotar is not compatible with the
BC-4 mount, because of its overall dimensions and weight. The unusual combination of
a focal length of 600 mm and an aperture of 300 mm makes it necessary to restrict the
usefulness of the lens for precision metric photography to a specific portion of the visible
spectrum.
The synchronization of between-the-lens rotating disc shutters for separated camera
stations to == 100 usec or better, depends on extremely delicate mechanical and electron-
ical components, incorporated into both the BC-4 instrument and the corresponding con-
trol equipment. But, even more complex, is the task of providing in the communication
link, signal stability to a correspondingly high degree of precision. The associated elec-
tronic equipment dwarfs, in complexity and cost, the actual photogrammetric components.
Technical detail pertaining to the photogrammetric cameras, auxiliary shutters and
electronic control equipment may be obtained from reference literature, mentioned at the
end of this paper.
It has been necessary to eliminate from this discussion considerable detail which is
important in the process of achieving an absolute accuracy of 1:100000 or somewhat
better in the final triangulation results. Nevertheless, it is hoped that the presentation of
the capabilities of Ballistic Photogrammetry in general terms will enable the reader to
appreciate the potential inherent in this branch of photogrammetric measurements.
Selected Reference Literature.
Schmid, H., A General Analytical Solution to the Problem of Photogrammetry, Bal-
listic Research Laboratories Report, No. 1065, Aberdeen, Maryland, U.S.A., July 1959.
Brown, Duane, A Treatment of Analytical Photogrammetry with Emphasis on Bal-
listic Camera Applications. Airforce Missile Test Center, RCA Data Reduction Tech-
nical Report No. 39, August 1957.
Witney, Charles A. and Veis, George, A Flashing Satellite for Geodetic Stu-
dies, Smithsonian Institution, Astrophysical Observatory, Special Report No. 19, 1958.
Putnam, R. E. A., Ballistic Camera (BC-4) Synchronization System, Ballistic Research
Laboratories, Aberdeen, Maryland, U.S.A. (Report under preparation).
Wild Heerbrugg, Switzerland, The Wild BC-4 Ballistic Camera.
Henson, Fred C., Pasadena, California, Auxiliary Capping Shutter.
Electronic Engineering Company of California, Santa Ana, Califor-
nia, Ballistic Camera Synchronization System.
RESUME.
Considérant que les méthodes de mesures photogrammétriques seront probablement
mises en application pour la mensuration de la trajectoire d'un satellite géodésique, exa-
minons divers secteurs d'application de la photogrammétrie balistique. Compte tenu de
la faiblesse de toute généralisation, on entrevoit dans la détermination des coordonnées
espace-temps de points isolés, la táche fondamentale de la photogrammétrie balistique.
Les problémes géométriques qui y sont liés et qui se présentent sous forme de multiples
recoupements et intersections, sont les mémes que les problémes formant la base de la
méthode photogrammétrique utilisée en topographie. La similitude résultant des problé-
mes théoriques et techniques relative aux études des erreurs et aux méthodes de restitu-
tion ainsi qu'aux instruments de lever et de restitution est discutée au point de vue géné-
ral, afin de faire ressortir leur influence sur l'ensemble de la photogrammétrie. Pour la
restitution numérique des problémes de photogrammétrie balistique, on se basera sur un
