4-1-7
consumed about 26 hours of flying time and yielded a
productivity rate of about 580 powerline spans per hour.
In addition to the 66 kv high-voltage lines, some 2000 spans of
lower voltage lines were also recorded, but at the slower rate of
165 spans/hour. The low-voltage lines required more aircraft
maneuvering. The selected imagery for stereo analysis filled 14
CD-ROMs and all extracted powerline survey data was
subsequently entered into a SMALLWORLD GIS.
6 CONCLUDING REMARKS
The airborne RCAMS demonstrates that a relatively
inexpensive mobile mapping system for powerline recording,
and specifically for mapping vegetation in support of bushfire
mitigation, can be configured through an integration of stereo
video imaging, kinematic GPS and inertial positioning sensors.
Moreover, utilization of the concept of photogrammetric self
calibration enables a complete system calibration for imaging
sensor interior and exterior orientation, which is necessary for
accurate triangulation and geo-referencing of feature points
within the recorded video imagery. The RCAMS application to
66kv powerline mapping described in this paper was carried
out in 1996. Were the system to be assembled today, it is more
likely that high-speed digital CCD cameras or digital video
technology would be employed instead of analog SVHS video,
and advantage would also be taken of both recent
developments in kinematic GPS and improvements in attitude
sensor technology. Otherwise, the proven basic design criteria,
processing algorithms and operational procedures would
remain essentially the same.
7 REFERENCES
Hunt, J., Rowlands, A. and Judd, A.M., 1998. Rapid Rail
Mapping of Queensland Rail’s Central Line. Proceedings of
CORE 98, Rockhampton, September 7-9, pp 15-21.
Leahy, F.J. and Judd, A.M., 1998. Precision Rapid Route
Mapping Incorporating Stereo Imagery. Presented paper,
ISPRS Commission II Symposium “Data Integration: Systems
and Techniques”, Cambridge, July 13-17, 8 pages.
Leahy, F,J. and Judd, A.M., 1999. Precision of Models for
Kinematic Positioning in Rapid Route and Facilities Mapping.
Proceedings of the International Workshop on Mobile
Mapping Technology, Bangkok, April 21-23 (this volume).
