iving all the nadir
i| position, should
) the normal strip
points common to
| optimum econo-
in be obtained in
90% overlap and
e photographs; or
n-pointing of each
nade possible by
nmands to some
Doppler, Aerodist
ymputer.
orted to provide
time, for instance
y per cent savings
rovement in flight
with coventional
1er improvements
mbined use of the
s or Startracking,
odist.
ition methods: for
scopes which give
in error of the or-
he radar altimeter
earance, mean er-
plus some metres
proven their value
o is called A P R.
vations and profi-
's of the order of
| hard points. This
l.
ntrol, that can, as
means of Shoran
mising new devel-
‘mance is expected
rder of one metre
ice. Verticality in-
y means of solar
the order of three
sible. The horizon
ay prove to be of
rticality indication
an error of the or-
rees.
great potential in-
ic inertial vertical
ves vertical photo-
ran error of three
erticals cannot be
ccurate for photo-
ntation, but they
SURVEY NAVIGATION, AUTHOR'S PRESENTATION 9]
can be used for planimetric mapping and for
the use of third order plotting instruments. They
supply verticality with mean errors of the order
of ten to twenty sexagesimal minutes, and there
is one highly corrected gyro system which now
performs at the order of five to ten sexagesimal
minutes.
[ would now like to give a few conclusions
regarding system integration. In many cases,
single methods alone are incapable of perform-
ing with highest accuracy — for instance, com-
pass, gyroscope, inertial instruments, and so on.
There is a trend towards combining various
methods — each one with their particular merits
and deficiencies — into integrated precision na-
vigation systems, such as: Doppler plus dead
reckoning; Inertial plus Doppler; Inertial plus
Startracking; Doppler plus Startracking on
Inertial platform; and so on. In this way, they
can be made to limit each other's error propa-
gation and instrument drift to within extremely
close limits. In addition, the output of these
systems is processed in computers — some of
them on analogue and some on digital — to bring
them in a form usable either by the automatic
pilot or by the camera orientation elements re-
corder, of by both.
That is a very condensed summary of the
situation today, in so far as it is disclosed in the
commercial sphere. In the field of automatic
guidance and space flights, the possibilities are
still more advanced. If you now ask what the
future will bring us then, of course, nobody can
predict this, but a short review of the history of
the one hundred years of aerial survey does
show the direction and the rate of development.
It may be of interest to show you the first
aerial photograph made one hundred years ago
now, by Mr Tournachon (see Fig. 1 of the in-
vited paper). His artist's name was Nadar. This
is an historical photograph taken from a balloon
on a wet plate. This was a time exposure taken
a few years after photography was first invented.
This next slide shows you Mr Nadar, the
first aerial photographer, in his balloon (see Fig.
l-inset of the invited paper). I may point out,
speaking about navigation, that this glass was
Mr Tournachon's navigation instrument.
[Then Mr Corten gave the following expla-
nations to slides which are not shown here].
This slide shows the way of working about
seventy years later, after the first world war.
This is visual survey navigation according to
Archives 4
conventional methods using a drift sight and
stop watch. It took seventy years to come that
far.
Around 1949, after the end of the second
world war, we saw the introduction of radio
navigation, for instance radar, in aerial survey.
It took only eight years to come to complete
instrument navigation controlled by human
operators such as has been used now for several
years in the United States Air Force aeroplanes.
You see the drift determination by means of
television. The television camera is mounted on
gyroscopically controlled mounting in the aero-
plane; track recording by means of Shoran, and
straight line computer; D6 gyro control drift
side; the camera is gyra controlled, and its ex-
posure is commanded by the atomic scanning
intervalometer, and so on.
It took only seven years to come this far, but
two years later in 1959 Lunik III photographed
the moon's back side. This was an automatic
camera station with self-contained navigation
photographing the moon from a distant flying
height, 6,000 kilometres distance, on a 35 milli-
metre film. There was automatic focusing and
film processing and the resultant photographs
were transmitted to the earth by radio.
Finally, I should like to show you my last
photograph (see Fig 2 of the invited paper)
which is also an historical one, taken exactly
one hundred years after the first aerial photo-
graph. This is a portion of the moon's back side
transmitted by radio to the earth.
Gentlemen, that is a condensed view which
shows that development is now proceeding very
fast and at an ever-increasing rate. This is the
important point today: some of the existing and
older methods are simple and surprisingly ac-
curate; in addtion, new methods become avail-
able. Let us realise that we have at our disposal
techniques of high accuracy which in the near
future perhaps might be able to revolutionise
photogrammetry.
Mr President, I would like to stimulate the
discussion in groups rather in order to avoid
confusion. I would propose first of all some dis-
cussion on survey navigation in the proper sense;
then elevation control, radar, altimetry, statis-
cope and so on; then planimetry, and perhaps
we have some results from Aerodist, from the
US A; and then we can hear perhaps about
verticality, and then integrated systems.