The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part Bl. Beijing 2008 
combination of GPS/INS sensors with image data for 
navigation allows more precise and reliable results. 
Furthermore, the integration of GPS/INS and image data in a 
real time triangulation method will drastically reduce time and 
cost required for post processing. 
Mini UAVs have been used recently for civilian applications 
like 3D city modeling (Wang et al., 2004), modeling of a 
medieval castle in Samen (Pueschel et ah, 2008), Horcher and 
Visser (2004) proposed applications in forestry like BMP 
Inspections, road maintenance of forest roads and trespas. 
Further on, UAVs were used in applications related to 
agriculture (Herwitz et ah, 2004; Rovira-Mas et ah, 2005; 
Eisenbeiss, 2007; Reidelstuerz et ah, 2007; Rovira-Mas et ah, 
2008) and for the documentation of an archaeological site 
(Lambers et ah, 2007). In these projects the focus was on a fast 
data processing, which reduces the accuracy of the results or in 
contradiction the results had high accuracy, while the 
processing cost still a lot of manual effort. 
Hence, our goal is the automation of the complete workflow in 
a way that the manual input can be reduced to an acceptable 
minimum. A further objective of our work is the high reliability, 
precision and resolution of the photogrammetric products like 
elevation models, orthophoto and textured 3D models. 
Therefore, the aim is to develop procedures for the UAV data 
acquisition and processing that can lead to a highly automated 
workflow and accurate complete results (see Figure 1). 
Project Parameters (PP) 
Autonomous Photogrammetric Flight (APF) 
1 
* 
Quality Check of the Data (QCD) 
xn 
<^QCD 
Cj 
QCD-aUAV BT 
.......i*.:. 1 .. 
UAV Block Triangulation (UAVBT) 
T 
<^UAV BT -aD03C 
DSM, Orthophoto, 3D Models (D03D) 
1 
J Modules 
1 1 
Definition of parameters 
Interfaces 
m 
Practical, data acquisition 
□ 
Fieldwork 
n 
Developing for UAV case 
l i 
Office work 
r~l 
Evaluation for UAV case 
Figure 1: Modular Workflow for processing of UAV data 
showing the main functionalities. 
All processing steps of the workflow are categorized in 
modules, which communicate with each other via interfaces. 
The interfaces are established in a way that for the individual 
module the attributes can change, depending on the project 
parameters. Additionally, the interfaces have the functionality for 
data transformation and formatting. Therefore, with our proposed 
workflow several UAV applications can be handled. The main 
modules are defined as follows: Project parameters (PP), Flight 
planning (FP), Autonomous photogrammetric flight (APF), 
Quality check of the data (QCD), UAV Block Triangulation 
(UAV BT), DSM, orthophoto, 3D Model (D03D). The individual 
procedures of a module can be a process or a part of a process 
from commercial or in-house developed software. 
Figure Figure 1 show which module are or will be developed by 
IGP and which focus more on the evaluation of existing 
commercial or in-house developed software packages. 
Additionally, figure 1 explains which part of the work will be 
possible during or after the field work or both. 
In the following, two developments related to real applications of 
such a mini UAV-system, which lead to the automation of the 
workflow, will be presented. Before describing the developments 
in detail, our mini UAV-system and its ground control station will 
be described. After all, the outcome of the developments and the 
direct benefits using an UVS system in the two specific 
applications are discussed. Finally, we will propose a new UAV- 
platform, which can lift a bigger payload. 
2. AUTONOMOUS MINI HELICOPTER 
The mini UAV-system Copter lb (see Figure 4 and Table 1) was 
developed by the French company Survey-Copter. It is equipped 
with an on-board navigation system (wePilot 1000) from 
weControl. The wePilot includes a GPS (Global Positioning 
System), an INS (Inertial Navigation System), which allows the 
mini UAV to perform attitude stabilization, position control and 
to navigate autonomously. The private company weControl 
GmbH is a spin-off of ETH Zurich that specialized in the 
development of miniature flight control systems for UAV-systems. 
Mini UAV-system Copter lb 
Length 
2m 
Rotor diameter 
1.8m 
Maximum takeoff weight 
15kg 
Payload capacity 
5kg 
Flight endurance 
Max. 45min 
Altitude 
1500m 
Range 
5km 
Table 1: Specifications of the mini UAV Copter lb 
(SurveyCopter, 2008). 
The navigation system features the following main characteristics: 
an altitude stabilization and velocity control, position and RC 
transmitter sticks interpreted as velocity commands, integrated 
GPS/INS system, altimeter, magnetometer, payload intensive 
flight controller, built-in data logger and telemetry capability, 
programmable hardware for rapid customization and an embedded 
computer system. Furthermore, the system consists of a ground 
control station (a laptop with monitoring software (weGCS)), a 
convertible gimbal for still video cameras like Canon EOS D10, 
D20 and the Nikon D2Xs, communication links, power supply, 
video link (inch video camera) for visual control for monitoring 
image overlap, and transport equipment. 
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