2G Robotics has collaborated with C&C Technologies, a leader in AUV technology to produce a new multi-sensor AUV for underwater pipeline surveying. To provide a very detailed pipeline inspection requires multiple sensors in order to create a full understanding of the asset. With this in mind, C&C’s new AUV is equipped with a series of sensors that include 2G Robotics ULS-500 Long Range Underwater Laser Scanner, a multi-beam echo sounder, high resolution digital still camera, geo chemical sensors for detection of methane (CH4), CO2, and PAH hydrocarbons, side-scan sonar and a sub-bottom profiler.
As is often the case, a single design approach may not always be the best solution to meet deployment requirements. The ULS-500 Long Range scanner is a modular system. It can be mounted in a tri-pod configuration for point and shoot scanning, shown here in Figure 2. However, the ULS-500 is not limited to this single design. C&C Technologies AUV requirements called for the ULS-500’s laser and optical sensors to be in separate housings designed to mount flush with the bottom of the AUV as shown in Figure 1.
The ULS systems can collect profiles of data points in two different modes. Using the tri-pod design, the ULS-500 can scan a continues 360° by rotating from a motor housed on the tripod stand below the optical sensor. This operation is called scanning mode (Figure 3).
C&C Technologies AUV called for the sensor to remain fixed to the AUV as it travels above the pipeline. The laser emits a 50° swath of laser light continuously collecting profiles. This operation is called profile mode (Figure 4).
To meet C&C Technologies requirements a number of design modifications were made. This 4500m rated laser system acquires 1400 points per profile line. The scan rate of the system can be operator adjusted in real-time from 3 to 30 Hz. This results in a maximum along track point density of 6cm and a maximum cross track point density of 5mm (Figure 5).
By combining multiple sensors, including the ULS-500 into one inspection AUV is incredibly useful in assessing the integrity of a pipeline. Multi-beam sonar provides a broad overview of the pipeline and surrounding area while the ULS-500 has a shorter range but with a significantly higher level of detail. This is especially useful for pipeline sections that are of higher concern such as free span areas. Using the ULS-500 to obtain data, decisions can be made with more certainty, thus reducing costs and liability, while increasing asset safety and longevity.
To learn more about how 2G Robotics underwater lasers scanners can be integrated into your own survey equipment click here or to sign up for a one-on-one online learning session where we will discuss how the scanners operate, look at some example scans and address your specific application requirements.