The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part Bl. Beijing 2008
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small regional large-scale topographic mapping task, we present
a new concept of aerial photographic system which employs a
three-dimensional civil unmanned surveying biplane and takes
the accuracy requirement as the main requirement of the system
design. Meanwhile, the photograph control, double-wing UAV
flight characteristics, the payload manufacturing requirements
are taken as non-dominant requirements, using a
multidisciplinary collaborative design model to carry on the
optimal solution to the design parameters.
The newly developed two-wing UAV which is with a length of
3.7 m, height 1.5 m and a wingspan of 3.5 m. The body of the
plane uses aviation balsa skeleton, and the focus components
use reinforced carbon fiberboard. The Airplane gross weight 40
kg, Take-off speed is 40 km/ h, Flying speed is 50 ~ 100 km/
h , cruise duration is 2h, control radius is 20 km , flight altitude
is 100 m —4 000 m, the DC—DC voltage transformation
module provides the overall system with the standard 5 V and
12 V voltages. As shown in figure 3. The payload is a Canon
IDsMark-II digit camera.
(a) Ground-pre
flight state
state
Figure 3. Unmanned aerial vehicle panorama drawing
3.2 Test Area Coverage and Flight Design
After the integration of the system, it has been tested
successively on such photogrammetry projects as anti
regulation reservoir in Xixia Yuan, Guangzhou New Passenger
Station on Wu-Guang Railway Passenger Line, Danjiangkou
Reservoir, archaeology of Han Tomb and rural drinking-water
projects in Huairou District, Beijing. Now we’ll take
Guangzhou New Passenger Station for example.
3.3 Test results
With the flight altitude of about 118m, and the ground
resolution of 5 cm, a total of 840 images are acquired in this
aerial photographic task. The images are clear, with uniform
color and no aerial loopholes. Both longitudinal overlap and
lateral overlap are 100% qualified, the largest photograph tilt
angle being 2°, the largest rotation angle 5°, the bending of the
route less than 1%, and the largest aircraft height difference 3m.
Figure 4 shows the thumbnails of the original images in the
coverage.
Directional points and checkpoints are totally field-controlled.
After image distortion correction and single absolute orientation;
the statistical results of the check point accuracy are as follows:
Me = 0.10m , My = 0.9m , Mz = 0.15m , which basically
meet the 1:500 scale map requirements.
Figure 4. Index map of Guangzhou new passenger station
4. UNMANNED AIRSHIP AERIAL
PHOTOGRAMMETRY TEST
4.1 Unmanned Airship and Payload
The test was carried out between October 1 st and 6 th , 2007.
Guangzhou New Passenger Station on Wu-Guang Railway
Passenger Line is located between Zhongcun Village and Shek
Pik Village of Panyu District, Guangzhou, where Wu-Guang
Railway Passenger Line intersects with the southern extension
of Guangzhou Metro Line 2. The photography area is between
east longitude 1131445 - 1131635 , and north latitude
22°58'47"-23°00'30". The actual flight area is 3.2* 3.2km 2 .
The survey area is flat with a distribution of rural residential
areas, nurseries, orchards and farmland.
The mode of manual take-off and landing is selected with
autonomous flight. As the aircraft is equipped with a parachute,
emergencies during the flight are handled autonomously by the
aircraft-borne controller, therefore, only one landing field is set
near the central zone of the surveyed area. The aircraft carries
out the real task of over-horizon autonomous flight. Four crew
members are involved and the effective operation time lasts
three days, including one day for route planning.
The airship flies with the buoyancy of the helium filled in the
ship pouch and the power provided by engine. In 1884, ever
since the success of the world's first flight test of a practical
airship, airship has become the most successful manned vehicle.
As the airship is strongly affected by weather conditions such as
winds and thunderstorms, airship was replaced by aircraft in the
1930s. However, people have never given up the development
and application of unmanned airships for the sake of their
unique technological advantages. Being eligible for low-
altitude and low-speed flight, small airships can be used as a
unique platform for the acquisition of high-resolution remote
sensing images.
The unmanned airship used in this test is self designed and
made by the Survey and Mapping Institute of Science and
Technology of China. As is shown in Figure 4(a), the airship
can fly autonomously and its performance is shown in table 2.
A Canon 5D camera is used, the CCD size of which being
4368*2912, the focus being 24mm.