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.