14 
Photogrammetria, XIX, No. 6 
For the second true course determining possibility (i.e. the line-of-sight) we use as 
A 
input the A points or ^ points obtained under oblique angle during previous line flight. 
Also, the accurate drift angle is introduced to obtain the correct relative bearing of the 
line to be flown; this relative bearing is also the true course output to be made good. 
The third true course determining possibility (i.e. the gyro-nadir or gyro-oblique 
position of the points when passed over) serve as a check on performance, showing the 
true track actually made good. 
3.7 Area limitation. Flight line length. Rectangularity. 
Deduced reckoning procedures are applied to a high degree of accuracy, using the 
displacement vectors and time, and computing DR either by means of standard methods 
or by means of doppler. 
Area and line 
llrr " tatl0 °- OUTPUT: Area delineation.Line position 
start and stop 
DR procedures and computation 
or: Doppler plus computer 
t 
INPUT: CH VAR D TH TAS WV At 
4. Survey navigation as a system. 
The flight elements and their functions are chosen so as to form a logical and 
coherent survey navigation system. It can be considered as a skeleton on which good 
navigation can be based. 
Following this, it is always possible, under whatever conditions of civil aerial survey, 
to obtain aerial photography which fulfills the strict specifications of a good flight lay 
out. Photo flights should be made in the most economical way and — even more impor 
tant — should allow for the most economical restitution. 
This skeleton, composed of the functions mentioned in the previous paragraphs, is 
presented in the figure on page 15. 
Final output: 
Flight height over reference Z r 
Reference scale E r 
Minimum side lap v x 
Line spacing A 
Line position TT and area limitation. 
5. Reference literature. 
[1] Brucklacher, W., Beitrag zur Navigation von Grossflächenflügen. Bildmess. u. 
Luftbildwes., Dec. 1950/51. 
[2] Brucklacher, W., Beitrag zur Planung, Vorbereitung und Durchführung pho 
togrammetrischer Bildflüge. Deutsche Geod. Komm., C 25, 1957. 
[3] Gleize, P., Carnec, a.o., Institut Géographique National, Les méthodes de na 
vigation en photographie aérienne. Internat. Archives, Comm. I, London 1960. 
[4] Jurkovskij, G. A., Chadzetlase, F. M., Instrumententalnij metod zachoda 
na sledujuscij aerofotosjemocnij marsrut ocnim razworotom, Trudi Laborat. 
Aerometodov, V, 1956. 
[5] Shershenj, G. A., Aerofotosjemka, Moskva, 1958.