12
Photogrammetria, XIX, No. 6
on the next flight axis in a minimum of time with a maximum of certainty. Its 15 scales
incorporate the relations mentioned in the previous paragraphs on a logarithmic scale.
3.4.5 Input — Output.
Line spacing by
approach turns
M +i =A
M - d -- A
GS At = i
2(1-cosY)R = d
£ût=N / '
forS-turn- >—v—=—forU-turn-
R (2cos8 + 1 -^ jL ^ sinS)= M
^ t t J
R
9.81 /o tan/3 V =£
t t
INPUT: fi TAS At
S GS At
Approach turns and their combinations are composed on various flight elements any
of which can be introduced as a given parameter or as a desired performance.
In a logical sequence, an angle of bank /? can be introduced together with the air
plane’s speed in turn (TAS) to produce a certain rate of turn e as output.
This rate of turn s, used as input together with the airplane’s turn speed V will
produce an air radius of turn R.
If a crosswind component is present, the resulting survey drift <5 can be introduced
as input together with the air radius of turn R to obtain the ground spacing M as output
in a ground coordinate system.
If an S-turn is required, the rate of turn e is used as input together with the elapsed
time A t to obtain heading change W as output.
This heading change used as input together with turn radius R produces S-turn
displacement d.
Displacement d subtracted from ground diameter M produces flight line spacing A
as final output.
If a U-turn is desired, the across-line ground speed GS is introduced during elapsed
time A t to produce intermission i as output.
This intermission, added to ground spacing M will result in flight line spacing A as
final output.
3.5 Side lap by line spacing.
3.5.1 Relation.
If (1—w r T ) = Z r tan (/? r + A/5) is used to obtain proper line spacing at all points,
the minimum side lap is obtained automatically. At any elevation h v the side lap v x is
obtained from A = s . E x (1—v x ).
3.5.2 Input — Output.
Side lap by
line spacing
A = line spacing
E x = local photo scale
s = image size
are used as input to obtain the desired
local side lap v x as output.
-i -i
1-A E. s =v.
A E. s
INPUT:
