REPORT ON THE ACTIVITIES OF WORKING GROUP I11/1
DURING 1980 - 84
Friedrich Ackermann
Photogrammetric Institute
Stuttgart University
Germany, Federal Republic
Commission III
Abstract: The experimental activities of WG III/1 concentrated on performance tests of various
methods and computer programs with regard to the detection of gross data errors in aerial
triangulation. Based on simulated data tests were carried out by members of WG III/1 and of
OEEPE Commission A. The results are summarized and conclusions are drawn.
With regard to the fundamental theoretical questions of the mathematical model of aerial
triangulation experimental evidence on the stochastic nature of image errors is available.
Based on the 1981 seminar of the WG the general situation is reviewed and experimental procudures
are suggested.
um Introduction
1.1. The Working Group 1! of Commission III was established at the 14th ISP Congress in Hamburg,
1980. It's given name "Identification and Elimination of Gross and Systematic Errors" refers to
two main problems of present day aerial triangulation. However, the Working Group III/1
understands its theme to be more general. It is really the general problem of the mathematica]
model of photogrammetric point determination or of modern analytical photogrammetry, respectively,
we are concerned with.
Accordingly, in its initial deliberations, the WG identified 3 main topics which are rather
fundamenta] and which, although interrelated, can be treated quite independently. They are:
- systematic image errors
- gross observation errors
- refinement of the stochastic model.
All 3 topics are part of the general problem of the fundamental mathematical model of photo-
grammetric point determination. They are also linked together in the evaluation of the total
accuracy performance of the analytical method and in the unsolved question of quality control of
the results.
1.2. During the period 1980 - 1984 the WG held 4 meetings, usually in connection with other
international occasions. It organized a 2 day seminar in Nov. 1981 in Stuttgart on "Mathematical
Models of geodetic/photogrammetric point determination with regard to outliers and systematic
errors" |1| and took part in the Symposium of Comm. III in Helsinki 1982. Also 2 wOrkshops on the
reliability of photogrammetric blocks held in Stuttgart in 1980 |2| may be mentioned here.
The experimental work of the WG concentrated on tests concerning the detection of gross errors
in blockadjustment. Up to 15 members took actively part in the experiments. Others observed
them closely. Most activities of the WG were done jointly with OEEPE Commission A. We thank here
its president, Mr. J. Talts, Sweden, most cordially for his kind support and cooperation.
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