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The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part Bl. Beijing 2008 
as not navigable 12.6% of the time with a height threshold 
parameter of 5=15 cm [6]. 
I 
Figure 5: An illustration of fused sensor maps 
performance was maximized. Terrain data can be from maps or 
aerial imagery, but high fidelity and accuracy are achieved by 
using POS data to register laser range scans into models that we 
call “drive-by topography.” These models are obtained by 
driving a vehicle equipped with laser scanner and POS system 
over terrain and recording topographic imagery. The method is 
broadly applicable for detailed surveys that are unachievable 
from satellite or aerial flyover [7]. 
Detailed terrain topography can be acquired by collecting range 
scanner and vehicle position measurements while driving. This 
was done with an HI Hummer called ‘Topographer’ which 
utilized a POS LV and laser scanner to derive drive by 
topography typically with ,25m resolution and 1.5m accuracy. 
This data is combined to generate a height map reconstructed by 
solving for the position of each range measurement in 3-D space. 
The resulting surface models provide resolution and accuracy 
that are unobtainable from satellites or from traditional maps. 
An example of the detail of topography is shown in Figure 7. 
Planning and Vehicle Control 
With reliable data from the POS LV integrated into the drive- 
by-wire systems of both Red Team Robots, pure pursuit 
tracking was made possible. However a method to maximize 
the performance of both vehicles was needed. 
Figure 7: Topography data overlaid on imagery 
Human drivers adjust to changing terrain / weather conditions in 
addition to interpreting a curves apex to maximize the 
efficiency of a turn rather than following a straight line denoting 
the curve and ‘jerking’ through it. This is not efficient and 
providing the robot with apex entry and exit information, in 
addition to terrain condition, are two ways in which 
Figure 8: Result of pre-planning process 
The entire robot preplanning process relies on accurate terrain 
and known parameters of vehicle performance to detail safe 
driving parameters while minimizing the time it takes to 
complete a section of the course [8]. The result of pre planning 
is illustrated in Figure 8. The black lines denote raw RDDF file 
waypoints and speed limits provided by DARPA. The red 
dotted path illustrates the route as edited by human planners 
heavily interpolating the original set of waypoints. These 
smoothed splines form the basis of navigating in and out of 
curves. Should obstacles be encountered, the robot generates its 
PA Coarse Waypoints: 
path segment 
Processed 
Path 
Spline Curve 
Segment 
Figure 6: Illustration of how small errors in position and orientation can provide erroneous terrain characterization