Situational Awareness A Missing DP Sensor output Improving Situational Awareness in Dynamically Positioned Operations Dave Sanderson, Engineering Group Manager. Abstract Guidance Marine is at the forefront of Dynamic Positioning (DP) reference sensing technology. This paper discuss the developments in sensor technology that are making autonomous vehicles a reality and introduces the latest advances from Guidance Marine that will enable vessels to follow this pursuit. RadaScan View is a new feature available to mariners that provides situational awareness during DP operations. Introduction Modern vessels are complex, mobile systems, increasingly making use of automation and advances in computing and technology. DP systems are one of the growing number of semi-autonomous systems. The inception of DP, around 50 years ago, gave capabilities beyond the normal operating parameters of typical vessels of the time. Today we push the current boundaries with increasingly complex, multi vessel, close quarters, precision operations (figure 1). During these operations multiple systems are required to be used in concert. With improvements in Vessel ergonomics, where a vessel system has a primary purpose, the user interface is often located in the correct place for that job. However, where a system could also be useful for a secondary operation, it is only occasionally given a second user interface. On a Platform Supply Vessel (PSV) for instance, the main DP control console gives a good view of the cargo deck, but there is rarely a radar screen to provide additional situational awareness available at the DP console. Figure 1 A complex, multi-vessel operation Navigation at sea Vessels at sea have to deal with an uncertain environment, which not only has little in the way of fixed markers, but can also move a vessel without it having an input, such as wave action or currents. Vessel crews know on a global scale where they are via global navigation satellite system (GNSS) inputs which are in turn linked with the electronic chart system (ECDIS). The combined system is very useful, but the ECDIS can only display data from the time of the last update. The ECDIS can be overlaid with Automatic Identification System (AIS) and other dynamic data, but this data can be limited, and there may be other changes since the last update - such as a new permanent structure. 1
Autonomy in the automotive world The automotive world offers a much simpler problem. Typically a car moves over a fixed, well defined landscape, and movement is solely controlled by the vehicle itself. In spite of the apparent simplicity of land based travel there is a growing trend for the use of Advanced Driver Assistance Systems (ADAS). These systems include Adaptive Cruise Control, Lane Departure Warning, Forward Collision Warning, Parking assistance, Blind spot monitoring (figure 2). Figure 2 Advanced Driver Assistance Systems All of these systems are steps towards an autonomous car - one that can transport its occupants from A to B without their intervention. On the way to that goal the systems are providing additional safety benefits, which leads to efficiency benefits lower fuel consumption, less disrupted travel due to accidents and similar. Towards autonomy with DP reference sensors DP systems accept references from several sensors. This allows for redundancy of inputs, and some sensors are better suited to than others to certain situations. Hence we have: Laser based systems - good for long range and high precision, but potentially compromised by the weather. Radar systems - All weather capabilities, but potentially less accurate than a Laser. Taut Wires - accurate and simple, but limited by depth, and possibly sea state. Hydro Acoustics good for an accurate position, but underwater noise can hamper them. None of the systems are perfect alone - they complement each other, and the DP system does not rely on a single one for all situations The technologies used in sensors for ADAS are similar to typical DP reference sensors, but unlike ADAS a typical DP reference sensor does not provide the user with much additional information. Its output is targeted for the DP control computer. A local DP reference sensor (such as a RadaScan) provides a local position, referenced to a target. This position is fed to the DP control computer, and the target, in Guidance Marine's industry standard Dashboard, appears on the Birds Eye View (BEV) - a representation of the sea around the vessel (figure 3). 2
According to the BEV on the user interface the sea looks like figure 4. There are no structures, but just target providing a position. In reality that Target is attached to something, usually a large static object, such as an Oil Rig. (Figure 5) Figure 3 Guidance Marine Dashboard User Interface, showing a single target Figure 4 Illustration of the BEV shown in Figure 3 Figure 5 Captain Oil rig, North Sea Supply vessels also operate around the clock, so as often as not the view will actually be like figure 6. In this scenario dark sea and sky, combined with bright dazzling lights make the scene difficult to understand visually. There is potential, for instance, to fail to see the crew transfer vessel in this example. 3
To gain a view of the surroundings vessels are equipped with a navigational radar. This is the vessels most used situational awareness tool. It is not without shortcomings - Generally the console is positioned to be available when the vessel is making passage. For a typical Platform Supply Vessel (PSV) this would be in the fore part of the bridge. When a PSV is actively working near a rig then it is controlled from the DP station, which is situated looking over the aft deck. As a result the Dynamic Positioning Operator (DPO) often cannot see the Navigation radar whilst working. Guidance Marine manufactures a specialist short range radar. The RadaScan family is designed to be operated at close range, down to 10 meters (figure 7). Figure 7 A MiniRadaScan Figure 6 MARS platform, Gulf of Mexico, at night Introducing RadaScan View To provide a situational awareness tool that was available to DP operators when they are using the DP console Guidance Marine has added a traditional Radar like output to MiniRadaScan. We call this additional functionality 'View'. Guidance Marine's Dashboard user interface (figure 8) is well liked by end users. It is the result of several years of Human Factors work, consultation with end users and engineering effort. 4
Figure 8 Guidance Marine RadaScan Dashboard Part of the Dashboard's simplicity is due to understanding what information is, and is not, required at any point of use scenario. In adding the 'View' functionality this Human Factors approach was continued. The Dashboard for 'View' enabled sensors adds a single new menu. (Figure 9). In this menu are simple controls to enable tuning of the View parameters. Figure 9 Radar Image control menu For Sensors which do not provide the 'View' functionality the Dashboard continues to work as previously. The RadaScan View sensor (figure 10) adds to the Dashboard an overlay of additional situational awareness. The key here is evolution, not revolution additional useful information, without detracting from the already satisfying user experience. 5
By combining the accurate position radar with this navigational view DPO's are now able to confirm the position of responders with respect to the asset. This reduces the DPO workload during approach, and can assist during Station Keeping with optimum vessel positioning. (Figure 11) Figure 10 A RadaScan View Figure 11 RadaScan View operational in the North Sea Sensor Collaboration The Radar image data might also be useful for other reference sensors, or their user interfaces. To promote this, the data from RadaScan View is available in an open, industry standard, format. This means that RadaScan View can provide data to other systems without the need for agreements between companies. For instance, the ECDIS chart system displays world level overlays from the satellite navigation system, and longer range Navigation radar overlays. The availability of RadaScan View data can fill in the shorter range, higher definition overlay, improving the crews ability to navigate under less than ideal conditions. Another application is with laser position reference systems where it can be difficult to identify the true laser targets because other retroreflective items, such as SOLAS tape, can create plausible clutter. Unlike the RadaScan system, where targets have a unique identity, current Laser targets are just detected as reflective objects. Figure 12 shows the long term test setup at Guidance Marine in Leicester. A RadaScan View (circled yellow), and a CyScan Mk4 are mounted externally on our factory. These units run 24/7 as part of a reliability test program. 6
Collocated on a building opposite are a radar target (circled yellow), and some retroreflective tape targets (circled red), (Figure 13). Figure 12 Long term test sensors mounted externally at Guidance Marine (RadaScan - yellow, CyScan red) Figure 13 Long term test targets (RadaScan responder yellow, CyScan reflector targets red) Using the RadaScan View we see the radar responder and its position on the building (Figure 14). The roof line of the building is clearly visible in the radar image with surrounding cars and trees and the yellow dot shows the position of the responder. Figure 14 Long term test RadaScanView Dashboard By making use of the RadaScan View data we can confirm, on the CyScan user interface that the laser targets are attached to the same building, and are in the expected locations (Figure 15). The 7
CyScan is tracking the 2 rightmost targets. Line of sight to the rightmost target is blocked by trees, which are just visible in the Radar image. Figure 15 Long term test CyScan Dashboard It is important to note that the sensors, and their user interfaces, remain independent of each other. The RadaScan View and its user interface are not connected to the CyScan or its user interface. The CyScan Dashboard is merely picking up and displaying the data that the RadaScan View sensor is making available on the network. The CyScan system is not performing data fusion to improve its performance, it is providing visual cues to the DPO to improve their performance. If, for some reason, the RadaScan View data stops being available, then the only loss in functionality is the radar image overlay. The CyScan, its DP interface, and user interface continue to operate just as they would have without the extra situational awareness data. This independence is vital, and must be considered in designing new functionality, to maintain the appropriate levels of redundancy during operations. Conclusions Additional situational awareness can provide assistance to a DPO, however, as with all things there are potential downsides. More instrumentation doesn t necessarily lead to safer operations and operators can find themselves looking at instruments when they should be looking out of the window. They can however, use the additional margin that technology provides to gain efficiency at the same risk level. Users can become overly reliant on the sensors to detect all hazards and become inattentive, they can feel 'out of the loop'. These factors must be addressed by careful user interface design which keeps 8
users feeling that they are in control, and where enough information is presented to direct the user s attention to the hazard, but not so much that it keeps them from using their eyes and experience. Training of people continues to be the best way to address this, but the improvement in supporting technology is a vital assistant which Guidance Marine strives to do with RadaScan View. References Images used in this document sourced from: Figure 1 http://www.offshoretechllc.com/projects/floatoverinstallation/2014/4/4/uinxmb1m9ws8nodxwo6vf1x5wt5y8o Viewed 11 th Figure 2 http://www.edn.com/design/automotive/4368069/automobile-sensors-may-usher-in-selfdriving-cars Viewed 11 th Other images Guidance Marine Ltd. 9