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All the possible conditional equations which may exist between the
unknown parameters of our problem can be divided into two types. In the first
group, all conditions shall be considered which introduce additional metric
information, as for example, the height of a point above a certain reference
surface, or the partial position of a point expressed by latitude ÿ and
longitude X or the slant distance between two relative control points of the
model or the differences in flying height between two successive aerial
photographs, etc, This type of conditional equation which shall be designated
‘as a metric condition is especially important for the wide field of photo-
grammetric applications using ground control points.
The use of photogrammetric measuring systems for the determination of
trajectories of missiles and the anticipated use of these methods to measure
precisely the trajectories of satellites, e.g. for obtaining geodetic basic
information, requires the introduction of & second type of conditional equation,
where the additional information is not metric in an absolute sense but re-
Stricted to the mathematical character of the trajectory. This type of
conditional equation shall be designated as trend ' condition. |
(a) Metric Conditional Equations
The mathematical form of & specific metric conditional equation is
influenced by the type of metric information given, and by the reference
coordinate system introduced for the solution of the specific photogrammetric
measuring problem, From the multitude of possible given metric information,
+he following selection can be assumed to be of special interest for terrestri-
al control points.
absolute points given by: Latitude ($), longitude (A) and elevation
(H) with respect to an ellipsoid of revo-
lution, the axes of which are denoted by
& and b
partial points given by: either latitude (9) &nà longitude (A), or
by elevation (H)
relative points given by: the slant distance between two relative
control points
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EEE i — D
MEA
