FLIGHT
: LINE
>| DISPLAY
N | EXPOSURE
STATIONS
PILOT
‘RA EXPOSURE
COMMAND
on the output
e airplaine to
the computer
ot, or by ma-
display which
lanned survey
; are the Ana-
avigation plot-
. Ground Posi-
a Automatische
tioning of such
llows (fig.17).
puter: Doppler
magnetic bear-
.S, (these data
truments), and
is of manual in-
elivers as out-
nd (magnetic),
1 grid coordina-
speed, ground
resent position
), drift angle,
put is display-
| with a trans-
id disk. Prede-
ght lines can
lose tolerances.
kes over as a
iter (using the
vector) in case
ils, e.g. due to
r surfaces (see
. USAF Auto-
lotting board
ler handling a
a and plotting
plane’s present
A.F. charts.
SURVEY NAVIGATION, CORTEN 73
Drift Positioning Camera counter
- Line being town
Groundspeed
Across Track
Fine
Nautical Miles 10ths
, 100ths
*
Along Track
Course set
Course achieved
BES
Adjustment
Track Drum
setting indicator DISPLAY
Fig.18. Mareoni Doppler transcei-
ver, tracking unit and display unit
as is used in Hunting's survey air-
planes.
Pre-determined photo
positions.
Bloc photography.
In order to be of optimum eco-
nomical value for photogrammetric
mapping, a Doppler survey system
equiped with a computer as de-
scribed before, can also be equiped
with a camera exposure command
in order to position the exposure
stations in the regular rectangular
pattern of bloc photography. Par.1.3.
Practical experiences to
date.
Doppler systems in use for aerial
survey are:
Radan PC-201 of General Preci-
sion Laboratory Inc.; Canadian
Marconi’s Airborne Doppler; AD
2000 of Marconi’s Wireless Tele-
graph Co., Figure 18, and others.
Large areas have been covered
by aerial photography and airborne
geophysical surveys, using Doppler.
Experiences are:
Drift determination, abortive fly-
ing, gap runs, searching for the
starting point and other ineffective
flying was reduced practically to
Zero.
In APR and in geophysical sur-
veys the “positioning” of the data
is greatly facilitated, in many cases
the previous flying and construc-
tion of mosaics was not necessary;
savings of 25% and 40% flight time
are reported.
Drift information is continuously
available, thereby improving the
isobaric surface’s slope for APR.
Precision turns for exact mutual
positioning of flight line axes. Dopp-
ler is not yet sufficiently accurate
for determining the camera’s plani-
metric coordinates; in some cases,
