Ebner: 
Ackermann: 
Strunz: 
Ebner: 
Strunz: 
AUTHOR: 
TITLE: 
DISCUSSION: 
Ebner: 
Thank you very much. Are there other questions? 
I have one question concerning hybrid systems. 
If you bring in additional measurements, e.g. geo- 
detic measurements, you usually also introduce 
additional unknowns. Your vector x would be 
enlarged, at least it should be formulated such 
that it could be an extended vector. Then it can 
happen that the additional parameters may not be 
determined or determinable. If one pushes hybrid 
systems to extremes, one could have the case that 
neither partial system in itself is determined, 
that it is geometrically stable. It is not very 
advisable to go in this direction, but it may 
happen, and then there are two problems. First, 
of course, it might be difficult in such a case to 
get approximate values for the linearization. The 
second problem is more serious, namely the problem 
of singularity. Now my question: Can you suggest a 
certain method with which to check whether the 
system or a part of the system is stabile,whether 
it is determinable or not? 
First these sensors should be analysed to get more 
a priori information about the adequate mathematical 
modelling and stochastic properties of the data. 
You are speaking about the planning phase now and 
Prof. Ackermann asked what you are doing in a 
practical case if this situation appears. 
In the block adjustment one should test these 
additional parameters on statistical significance. 
D. Mihajlovic (Yugoslavia) 
A PROGRAM CONCEPTION FOR INCLUDING GEODETIC 
OBSERVATIONS AND OBJECT INFORMATION IN PHOTOGRAM- 
METRIC BLOCK ADJUSTMENT WITH INDEPENDENT MODELS 
Thank you, Mr. Mihajlovic, for your presentation 
in my language. With a few words I would like to 
say, you have presented a program conception for 
including geodetic observations and object informa- 
tion in photogrammetric block adjustment with 
independent models. You have said something about 
the use of this method in contrast to the use of 
the bundle method. You said that the additional 
information is described in independent coordinate 
systems. Together with the photogrammetric models 
it is included in the block adjustment. The advan- 
tage of this procedure is that the banded boarded 
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