UAV FOR MAPPING
—LOW ALTITUDE PHOTOGRAMMETRIC SURVEY
LIN Zongjian a *
a. Chinese Academy of Surveying and Mapping, 16 Beitaiping Road, Haidian District, Beijing 100039,
China, lincasm@casm.ac.cn
KEY WORDS: Photogrammetry, Mapping, UAV, Automatic Aerial Triangulation, Camera Calibration
ABSTRACT:
Two kinds of platform are accepted for mapping UAV system. One is remotely-piloted aircraft. Another is unmanned helium airship.
A super-wide-angle camera is constructed by four digital cameras, mounted in different optical axis directions. A high accuracy
calibration method is used to make compensation for the deformed errors due to the light and simple constructed mechanical frame.
According to the feature of data get from the UAV acquisition system, a special aerial triangulation program has been developed.
The DSM is automatically generated by image matching and TIN interpolation. It needs a little manual interaction operation to
separate the points upon the building or lie down at grand for generation DEM. The DOM is also produced automatically based on
the orientation elements and DEM results. As a research results, the UAV mapping system MAP-UAV has carried out several
experiments.
1. INTRODUCTION
Over the last few years remote sensing technology has
advanced in leaps and bounds. So much so that today it has far
outgrown the capabilities of its two main carriers, the satellite
and manned aircraft. With the fast growing need for highly
accurate and detailed observation data required in fields such as
environmental, agricultural and natural resources monitoring,
image quality and accuracy gained via satellites is far from
adequate. Also, data collection can be extremely slow and is
only possible under cloudless conditions. Although manned
aircraft offer sufficient resolution and accuracy, they are
expensive and have a limited endurance of only a few hours.
The limitation of satellites and manned aircraft are high
launch/flight costs, slow and weather-dependent data collection,
restricted manoeuvrability, limited availability, limited flying
time, low ground resolution "-(Pegasus 2004)
As an efficient supplement to remote sensing data collection
from satellites and manned aircraft, UAV image acquisition
technologies have been developed.
From the application point of view, there are two kinds of UAV
remote sensing technology need paying attention especially.
One is high altitude remote sensing in stratosphere. Another is
low altitude UAV photogrammetric survey. Pegasus has
introduced the technology of UAV remote sensing in
stratosphere on the 20 th ISPRS congress. In this paper, we only
introduce low attitude UAV photogrammetric survey.
The reasons to develop the technology of UAV for low altitude
photogrammetric mapping are as follows: 1) to perform very
low altitude aerial photography at cloudy day, 2) to get full
image of city building form different direction by complicated
flying, 3) to supply a cheap and easy system for engineering
organization for high frequency needs of aerial
photogrammetric survey.
2. PLATFORM
Two kinds of platform are accepted for mapping UAV system.
One is remotely-piloted aircraft. Another is unmanned airship.
The useful load required is up to 15 kg. The photographic flying
height is between 100 and 4000 meters, with speed 18—160
kilometres per hour. The remote pilot has both manual remote
operation and automatic programming control functions. A
simple constructed two dimensional stabilization plant are
designed to keep the image sensor’s optical axis directed at
vertical.
Length of Aircraft
2.8m
Take-off Weight
SOKg
Wingspan
3.6m
Size of Task Cabin
300mm X 500mm X 300mm
Take-off Speed
70km/h
Task Load
>8kg
Speed
70—160km/h
Aviation Time
3—4h
Navigation
Precision
^80m
Radius of Control
50km
Control
Program-controlled,
remote-controlled, self-
control
Height of aviation
100m~4000m
Figure. 1. picture of unmanned aircraft
Figure 1 shows the unmanned aircraft for low altitude
photogrammetric mapping.
Corresponding author. Tel.: +86-10-68187752; fax: +86-10-68218654.
