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BALLISTIC PHOTOGRAMMETRY, DISCUSSION 57
rays is the condition on which you base the
determination of the standard errors; is that
correct? Is it the condition of the relative
orientation upon which you found this deter-
mination of the condition? I think that the rays
should intersect at one and the same point in
space.
Mr G.H. ROSENFIELD: It is based upon the
orientation being known, being error free.
Generally speaking, orientations have errors in
them, but we will not use orientation which has
a mean error of the adjustment for orientation
that is greater than the random measuring er-
ror. So we do have a good orientation to start
with for the ballistic cameras. Having good
orientations we compute the position point
using six cameras for every one position point.
In this adjustment we again obtain a mean
error of approximately 3 microns of the same
order of magnitude as the random measuring
error again, so we feel there are no biases in
the adjustment. We use the same technique
with the CZ R type cameras and here we have
quite a large mis-orientation in each camera. If
we have a target board orientation the target
boards are restricted to the lower portion of
the plate and we have just 4 or 6 target boards.
With a random measuring error of 10 microns
we may have a mean error of orientation of up
to 17, 25 or 30 microns, so we know we have
error in the orientation. Then we triangulate
using the same mathematics as used with the
ballistic cameras. We come up with mean er-
rors of the adjustment of sometimes 100 or
180 microns, anywhere from 12 through 40
times the random measuring errors. In these
cases we know we have bias in the results but
we do not get this in the ballistic camera
system. In the ballistic cameras the mean er-
rors are approximately the same as the random
error.
Mr B. HALLERT: May I ask you a little
question about terminology? When you say
mean error do you mean the mean square error
or average?
Mr G. H. ROSENFIELD: The mean square
error; the standard error is the weighted sum
of the squares of the residuals divided by the
degrees of freedom.
Mr B. HALLERT: From a normal equation
system?
Mr G. H. RoseNFIELD: Yes, I have about
30 or so papers which I will place on the table,
and these go into a little more detail than I
have been able to do.
Herr Prof BURKHARDT: Ich hätte ja gern
noch einmal gehört, wie heute die Abgrenzung
ist zwischen der Aufnahme von der Erde aus
und der Flugbahnbestimmung von mitgenom-
menen Kammern aus. Aber ich glaube, da ist
die Zeit wohl zu knapp geworden. Vielleicht
machen wir eine Pause von fünf Minuten.