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Doppler Navigator
guides the aircraft on a predetermined course,
determines distance between each exposure station,
and yields data necessary for computation of the
slope of the isobaric surface.
Statoscope determines the difference in elevation of each
exposure station relative to an isobaric surface.
The most valuable for aerial triangulation is the horizon camera
because it provides tip and tilt information with a high degree of accuracy.
Introduction of the independent and OJ data in the aerial triangulation
procedure eliminates the double summation of errors present in aerial triangula
tion without the use of such auxiliary data.
Integration of the data from these auxiliary instruments into a
single mapping system suggests new approaches to the problem of extending control
by photogrammetric methods. Independent stereo pairs of different flight lines
can be combined into one block. It is possible to bridge entire areas rather
than strips. This approach permits greater flexibility in the planning of flight
lines, in the selection of the method of bridging, in the location of ground
control, and in the choice of photogrammetric instruments for triangulation.
4.2 Instruments for Aerial Triangulation
The aerial triangulation methods based on the transferring of the
elements of absolute orientation from one stereo model to the next by means of
instrumental procedures or analytical methods necessitate the use of expensive
first-order plotting instruments or comparators. When the orientation elements
of the aerial camera are determined from auxiliary instruments, simple photo
grammetric plotting instruments such as the Wild B-8 Autograph can be used for
aerial triangulation. The important requirement such a plotter must fulfill is
that it be stable and be equipped for accurate introduction of '‘P and CaJ on
the left and right plate holders. We have used the Wild B-8 very successfully
for aerial triangulation in conjunction with vertical super-wide angle photo
graphy obtained with the Wild RC-9 camera.
