- 37 
east similar, to the use 
positions of geodetic re - 
e compilation of topogra - 
s serves the disciplines 
in support of the problem 
jh-altitude auxiliary tri - 
al geodesy is to be seen 
ons of a sequence of points 
dure, due to a somewhat 
nost accurate spatial tri- 
m of the electronic ran - 
data for the determination 
n used for tracking satel- 
ions, or the determina - 
characteristics of the 
trie cameras are at fixed 
ance of photogrammetry 
satellites on the overall 
ition possibilities provi- 
^sterns. The development 
the broader concept of 
>es of raw data. The most 
o provide the means for 
f satellite orbits. 
a acquisition processes 
rrors, in order to be 
imulation of numerous 
5 . These perturbations 
ric components, and to 
)cesses. Further pertur- 
re of the environmental 
Id of " Satellite Photo - 
c photogrammetric me 
ed, providing predomi- 
n be qualitated by statis- 
:he basic problems of 
lown the possibility of 
> of geodesy. This will 
ational field as a whole 
Df a priori hypothesis. 
By applying the concepts of modern mathematical statistics, these sophisticated mathematical 
models will serve as a base for adjusting classical and satellite observations, not only in terms 
of the somewhat vague concept of errors, but in reference to the continuously increasing inter 
disciplinary knowledge of the various parameters of our physical world. 
If the modern concepts in geodesy are considered in connection with the possibilities 
offered by satellite geodesy, it becomes evident that a logical unified approach to the basic pro 
blem of geodesy can now be envisaged. This unified approach has, as its ultimate purpose, the 
establishment of all points of the physical surface of the earth in terms of a world-wide three - 
dimensional Cartesian coordinate system, the origin of which is at a point representative for 
the center of mass and one of whose axes is the rotational axis of the earth. 
In geometric geodesy it seems feasible, because of the potential of the high speed elec 
tronic computers, to abandon the two-dimensional scheme of classic triangulation, which is ba 
sed on the theory of surfaces, by replacing the theoretically rather abstruse concept of geode 
sics with a concept based on straight lines in three-dimensional Cartesian space. 
Such an approach is more economical, simpler and theoretically more transparent. 
The corresponding mathematics can be expressed by relatively simple closed formulas. 
The significance of three-dimensional Euclidean geometry, however, becomes self 
evident in connection with photogrammetric satellite triangulation methods which, by the very 
nature of their geometrical contents, demand three-dimensional solutions. 
The revolutionary significance of photogrammetric satellite triangulation is that such 
an approach provides geodesy, for the first time in its history, with the means to create a 
three-dimensional world-wide reference system which is not related to the direction of gravity. 
This system will provide an absolute reference frame of stations around the globe to which can 
be tied both the predominantly geometrically-oriented mapping programs and the evaluation of 
satellite orbits for determining gravitational and related geo-physical parameters. 
Specifically, the main objective of geometric' satellite geodesy is the establishment of 
a world-wide reference system by determining, with the highest possible accuracy, the three - 
dimensional positions of a selected number of points on the physical surface of the earth. This 
will be accomplished by the use of a passive, sun-illuminated satellite, using precision geodi 
meter traverse base lines, or an electronic satellite ranging system, for scale determination. 
The purpose of such a three-dimensional triangulation is : 
a - To provide a world-wide reference net* to which all geodetic-topographic end products 
can be related. 
b - To replace, for the determination of the shape and size of the earth, the classic, time 
consuming, long arc triangulation methods by a much more economical and theoretically supe 
rior approach. 
c - To produce a world-wide reference frame of control, to which can be tied continental, 
three-dimensional reference nets ** on all accessible land masses, by again using photogram 
metric triangulation with passive satellites. 
Such a continental net will provide the necessary control for numerical photogramme - 
trie aerial triangulation executed from extremely high-flying aircraft or satellites. In this way, 
the geodetic control pattern will be further intensified in local areas, in order to provide con - 
trol density in accordance with specific topographic mapping requirements***. The creation of 
such a control pattern will provide an economical approach to world-wide mapping programs, 
and at the same time provide the geodetic community with a data library for a fast-response 
mapping capability. 
* Compare flow chart-world-wide reference net 
** Compare flow chart-continental reference nets 
*** Compare flow chart- 1st, 2nd and 3rd order triangulation nets