Condition Survey of Coastal Structures Using UAV and Photogrammetry
Australasian Coasts & Ports 2017: Working with Nature, pp.704-710
Australasian Coasts & Ports Conference, 2017 (Cairns, Australia, 21-Jun-2017 - 23-Jun-2017)
Engineers Australia
2017
Rock seawalls and groynes are common coastal structures, but these flexible type structures can be damaged. Monitoring of these structures, particularly after severe events, can enable repairs to be implemented economically before a major and costly failure occurs. The conventional method, until recently, has been topographic surveys based on total stations or GNSS and ground observations, which can be time consuming, costly, may not fully identify movement or cracking of individual rocks, and can present WH&S issues. This paper investigates the application, accuracy and limitations of UAV (drones) mounted with high-definition cameras. These relatively low cost systems can, with correct operation, ground control and data processing, produce accurate 3D topographical surveys of structures (< 0.1 m precision). As an example, a drone mounted with a 12Mp camera was recently used to capture a 1.1km length of Belongil Beach, Byron Bay NSW, which included several rock boulder/rubble seawalls. The drone is owned and operated under CASA regulations by University of Sunshine Coast. Aerial photos were captured along a pre-programmed flight path with 80% overlap, at a drone elevation of 70m above ground, with collection of GNSS base data, and ground control, requiring two hours. The aerial images were processed using photogrammetric software (Agisoft Photoscan) to produce very accurate digital elevation models and orthophoto mosaics based on Structure-from-Motion algorithms. The quality of the topographical survey was determined to have a precision and vertical accuracy similar or better than airborne LiDAR with root-mean-square error values of less than 0.1 m for residuals, capturing the dimensions and position of individual rocks across the seawall structure. The topographic survey and orthophoto mosaics successfully provided an accurate and cost-effective 3D snapshot of the seawalls that, in turn, provided data for repair of the seawalls as well as updrift and down drift erosion scarps.
- Condition Survey of Coastal Structures Using UAV and Photogrammetry
- S King (Author) - International Coastal ManagementJavier X Leon (Author) - University of the Sunshine Coast - Faculty of Science, Health, Education and EngineeringM Mulcahy (Author) - International Coastal ManagementL A Jackson (Author) - International Coastal ManagementB B Corbett (Author) - International Coastal Management
- Australasian Coasts & Ports 2017: Working with Nature, pp.704-710
- Australasian Coasts & Ports Conference, 2017 (Cairns, Australia, 21-Jun-2017 - 23-Jun-2017)
- Engineers Australia
- School of Science, Technology and Engineering; School of Science and Engineering - Legacy; Sustainability Research Centre
- English
- 99450465502621
- Conference paper