72 SURVEY NAVIGATION, CORTEN
Computers. : GROUND. n
The Doppler infor- |poprier | WAL. PRESENT PRESEN, | TRF" 2 L'estance | ph
mation, to be used for | papar d POSITION. x | DISTANCE es DISPLAY
navigation, can be com- vetociry | COMPUTER COMPUTER | DESTINATION | STATIONS
bined with the com- CAPES
puter as illustrated in D. AUTOPILOT
See a6 ox naviga: HEADING —— > CAMERA EXPOSURE
ional purposes, the DESTINATION
computer must trans-
form the Doppler in- HEADING
formation and the REFERENCE : ;
Fig. 16.
heading information
into polar coordinates (course + distance vector) but for survey navigation the output
should be supplied in rectangular or grid coordinates in order to enable the airplaine to
cover predetermined parallel flight lines; this can be achieved by having the computer
command the autopilot, or by ma-
nual flying on the display which
may be a map with planned survey
Grundgeschwindigkeit
RE ALT a. Dopplerradar
PLN
\ TTT Abtrift
i ; flight lines. Examples are the Ana-
|, Magn. |Kreiselstabilisierter dac, the Automatic navigation plot-
Steuerkurs Kompof ting board, Marconi's Ground Posi-
Koppelrechner tion Indicator, and the Automatische
Eigen- Eigen” Koppelkarte. The functioning of such
(geschwindigkeit | geschwindigkeitsmesser
a system may be as follows (fig.17).
! Input into the computer: Doppler
velocity, drift angle, magnetic bear-
' ing, airplane speed IAS, (these data
d Kors ober Grund Inputs by means of instruments), and
NS the grivation (by means of manual in-
put). The computer delivers as out-
put: course over ground (magnetic),
course over ground (in grid coordina-
tes) airplane ground speed, ground
distance travelled, present position
(in grid coordinates), drift angle,
wind vector. This output is display-
ed at a map, supplied with a trans-
parant flight line grid disk. Prede-
termined survey flight lines can
thus be flown within close tolerances.
The computer takes over as a
Kurs über Grund
Kurs
| zum Ziel
Grivation
fem = m
O Kortengerät
Fig. 17. dead reckoning computer (using the
Abtrift — Drift air speed and wind vector) in case
Eigengeschwindigkeit —
Grundgeschwindigkeit —
Kartengerät c
Koppelrechner —
Kreiselstabilisierter
Kompass —
Kurs über Grund —
Kurz zum Ziel —
Indicated air speed (IAS)
Ground speed
Map display
DR Computer
Gyro compass
Track
Course to destination.
the Doppler signal fails, e.g. due to
the presence of water surfaces (see
paragraph 1.1). The USAF Auto-
matic navigation plotting board
consists of a computer handling a
number of input data and plotting
continuously the airplane’s present
position on standard A.F. charts.
