Terrain Maps – Lessons Learned and New Approaches: A Global Implementation Using Egocentric Viewports


  1. Broten, G.S.
  2. Monckton, S.P.
  3. Collier, J.A.
  4. Mackay, D.J.
Corporate Authors
Defence R&D Canada - Suffield, Ralston ALTA (CAN)
In 2002 Defence R&D Canada changed research direction from purely tele-operated land vehicles to general autonomy for land, air, and sea craft. This research, conducted under the Autonomous Land Systems (ALS) project, developed the Raptor unmanned ground vehicle (UGV), which successfully demonstrated autonomous capabilities. A key capability developed under the ALS project was a terrain mapping technique for representing outdoor, unstructured environments. Although the original ALS terrain mapping technique performed adequately, extensive testing and experimentation revealed weaknesses in its egocentric approach, principally due to the rotation of the map when the vehicle executed sharp turns. To correct this weakness, it was replaced with a locally-referenced global map that scrolls relative to the fixed cardinal directions. The vehicle remains in the centre of the global map and the map scrolls as the vehicle moves. An egocentric view, required for obstacle avoidance, is derived from the global map using a viewport. Extensive testing on the Raptor UGV revealed the global terrain map’s performance was superior to the egocentric terrain map approach. Using this technique, the terrain map more accurately represented and tracked terrain features. Additionally, since the vehicle remains at the centre of the global terrain map, this technique retains a record of recently traversed terrain, thus allowing for backup manoeuvres without requiring a rearward looking laser.

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Report Number
DRDC-SUFFIELD-TM-2006-189 — Technical Memorandum
Date of publication
01 Dec 2006
Number of Pages

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