The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Voi. XXXVII. Part Bl. Beijing 2008 
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commercial digital camera, and an inexpensive IMU (FOG: 
Fiber Optic Gyro) are proposed for multi sensor integration, and 
these sensors are low cost in comparison with existing aerial 
measurement system. These low cost equipments are easy to 
find in market. “Mobility” means light weight system and 
simple system to modify. Weights of sensors are shown in 
Table 1. That is, this system can be borne by a variety of 
platforms, any kinds of UAV, and not only an UAV but also 
ground vehicle, carrying by human, etc. These sensors do not 
own excellent specification, but they are light and low cost with 
enough specification. These handy sensors are used and make 
excellent results by integrating of sensors. 
Sensors 
Model 
Specification 
Digital 
Camera 
Canon 
EOS 10D 
3,072x2,048 pixels 
Focus length: 24.0mm 
Weight: 500g 
Digital 
Camera 
Canon 
EOS 5D 
4,368x2,912 pixels 
Focus length: 15.0mm (Fish eye lens) 
Weight: 500g 
IR 
Camera 
Tetracam 
ADC3 
2,048x1,536 pixels 
Green, Red and NIR sensitivity with 
bands approximately equal to TM2, 
TM3 and TM4. 
Focus length: 10.0mm 
Weight: 500g 
Laser 
Scanner 
SICK 
LMS-291 
Angular resolution: 0.25° 
Max. Distance: 80m 
Accuracy (20m): 10mm 
Weight: 4,000g 
IMU 
Tamagawa 
Seiki Co., 
Ltd 
TA7544 
Fiber Optic Gyro 
Accuracy 
Angle: ±0.1° 
Angle Velocity: ±0.05°/s 
Acceleration: ±0.002G 
Weight: l,000g 
GPS 
Ashtech 
G12 
Accuracy Differential: 40cm 
Velocity Accuracy: 0.1(95%) 
Weight: 150g 
Table 1. List of sensors 
2.2 UAV Platform 
In this research, all the measurement tools are mounted on the 
UAV, RPH2, which is made by Fuji Heavy Industries Ltd., 
shown in Figure 1. The size of RPH2 is a length of 4.1m, a 
width of 1.3m, and a height of 1.8m and weight is 330kg. 
Payload is approximately 100kg. All the sensors are tightly 
fixed under the UAV. RPH2 is quite big UAV, however, in this 
study, RPH2 is considered as testbed which is a platform for 
experimentation for development of multi sensor integration 
algorithm. RPH2 has large payload, so many sensors and 
control PCs with large battery can be mounted during 
experiment. After the development of the multi sensor 
integration algorithm, small UAV system, as shown in Figure 2 
is implemented with selected sensors for certain observation 
target. 
There are several advantages to utilize an UAV. One of the 
most advantageous things is unmanned platform, so it can fly 
over dangerous zone such as disaster, floating ice, land mines, 
and so on. Advantage of UAV suits the purpose of direct geo- 
referencing of this research. Direct geo-referencing does not 
require ground control points with accurately measured ground 
coordinate value. In dangerous zone, it is impossible to set 
control points unlike normal aerial surveys. Therefore, 
combination of this direct geo-referencing method from an 
UAV might be ideal tools for dangerous monitoring purpose. 
Therefore, the targets of this mapping system are for disaster 
such as landslide and river monitoring, not for urban area. 
In addition, for conducting safety operation, the UAV is 
restricted to fly over people, houses, and cars, also, the UAV 
doesn’t fly if wind speed is more than 10 m/s. In the experiment, 
the UAV flies about 1,6m/sec. of speed for acquiring laser point 
data with sufficiently fine resolution and sequential digital 
camera images with sufficient overlaps. 
Figure 1. RPH2 
Figure 2. Small UAVs 
2.3 Setting of Sensors 
All the sensors are tightly fixed on the UAV to have constant 
geometric relationship. Calibration of CCD cameras is 
calculated for interior orientation parameters such as focal 
length, lens, distortion, principle points, and interior orientation 
(Kunii and Chikatsu, 2001). Estimation of relative position and 
attitude among the sensors is also conducted (Shapiro, 1987). 
All the sensors are controlled by one laptop PC and they are 
synchronized by GPS time (one pulse per second). Sensors are 
set as shown in Figure 3. Digital video camera is also put on the 
UAV. This video camera sends images to the ground on real 
time to monitor flight course. RPH2 has large payload, so it is 
not necessary to think about weight. Large battery is also set to 
supply sensors and PC with electric power during the 
experiment. It is possible to flight long period.