VQ-820-G/Bathymetric Demo Case Study
The demand for accurate data and reliable performance is consistently required in the laser scanning industry. In the fields of hydrography and bathymetry, high-resolution and high-precision laser scanners, such as the RIEGL VQ-820-G, are necessary in order to produce data of the highest quality and precision. The deliverable renders the most precise information for accurately monitoring hydrographic and bathymetric requirements.
Such requirements are river and coastal degradation, flood prevention, reservoir sedimentation, structure and zone variations of coastal areas, hydro-archaeological surveying water flow and water level dynamics, surveying for hydraulic engineering, monitoring of hydraulics laboratories, and measurement for aggradation zones. In order to evaluate these concerns, repetitive surveys must be completed over coastal strips, sea beds, and the grounds of rivers and lakes. This is most effectively achieved by employing high-resolution airborne laser scanners.
The RIEGL VQ-820-G hydrographic airborne laser scanner was created for this purpose. The scanner itself enables the surveying of shallow water areas, land, vegetation and buildings at a new level of spatial resolution. This is due to its capability of acquiring 200,000 measurements per second and having a pulse repetition rate of up to 550 kHz, as well as a low beam divergence of 1 mrad. The scan mechanism itself is based on a rotating multifaceted mirror with the scan line tilted by about 20 degrees. This offers a wide field of view of up to 60 degrees and a scan rate of up to 200 lines per second.
The laser source of the VQ-820-G operates with a green wavelength at 532 nm, which allows penetration of the water’s surface up to 1 secchi depth from an eye safe altitude. The scanner itself is compact, rugged and lightweight that helps provide an easier installation into existing airborne scanning platforms and can be used in any type of aircraft.
In addition to the scanner, there is also a complete RIEGL software suite for data acquisition and processing, and can be coupled with RGB aerial photography, hyperspectral images and collected topographic data, that can extend the capabilities for further monitoring, research, and management.
A demonstration of the VQ-820-G was held in Fort Lauderdale, Florida to showcase the abilities of the VQ-820-G and to highlight the need of the scanner in the hydrographic realm of airborne laser scanning to multiple companies and government agencies. For the demonstration, the scanner was mounted in a Twin Otter utility aircraft with an aerial camera system and flew four test sites, along with a separate boresight calibration. The smooth and simple integration, installation, and operation of the VQ-820-G are notable factors about the scanner that was observed during the demonstration by the attendees.
During the tests, water penetration was 5 to 10 meters underneath ‘normal’ sea state conditions, where ‘normal’ indicates not optimal conditions, and the point density was 10 to 15 points per square meter. Despite not having optimal conditions, the VQ-820-G had consistent and excellent results where it was possible to see the water’s surface, the sea floor and returns from the surrounding vegetation and buildings, due to the scanner’s multiple target capability.
The results of the tests showed that the VQ-820-G performed exceptionally well over shallow water areas, shorelines, canals, buildings, and land. The scanner’s performance over these varied areas show the versatility available, seeing as it has proven difficult for other conventional bathymetric techniques such as side scan sonar systems, multibeam sonar systems and current bathymetric LiDAR systems.
The key factor to RIEGL USA’s success is providing complete support and reliability to our customers. From your initial purchase, to integration of the system, as well as training and support, RIEGL USA stands out in the industry as a leader. RIEGL USA located in Orlando, FL, is the North American office for RIEGL Laser Measurement Systems, GmbH. With over 19 years of experience, RIEGL USA delivers quality airborne, mobile and stationary terrestrial laser scanning solutions.
RIEGL Laser Measurement Systems, GmbH, is headquartered in Horn, Austria. RIEGL has more than 33 years’ experience in the research, development and production of laser rangefinders, distance meters and scanners. RIEGL is dedicated to designing, developing, and producing the best possible laser sensors for the desired application in order to perfectly fulfill the given measurement tasks and therefore, fully satisfy the customers’ expectations worldwide.
RIEGL is recognized as the performance leader in the airborne scanning, mobile mapping, hydrographic, civil infrastructure, mining and terrestrial based industries. Our instruments are well known for their ruggedness and reliability under demanding environmental conditions. RIEGL’s various 3D scanners offer a wide array of performance characteristics and serve as a platform for continuing “Innovation in 3D” for the laser scanning industry.
7035 Grand National Drive, Suite 100
Orlando, Florida 32819
James Van Rens,
Riegl USA President
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