What are SPRINT-Nav and dynamic positioning?

At Sonardyne, we combine our SPRINT INS (inertial navigation system) and Syrinx DVL (doppler velocity logger) alongside a high accuracy pressure sensor, to create the SPRINT-Nav system, a compact all-in-one navigation instrument for underwater and surface vehicles.

Dynamic positioning (DP) is a computer-controlled system which is used to automatically maintain a vessel’s heading and position without relying on the use of mooring lines or anchors. DP systems rely on position reference system’s (PRS) feeding into the DP system to monitor the vessels position and react accordingly to maintain a position and heading. To add robustness to the DP system, different types of PRS’s are used. This ensures that if one PRS is no longer available to the DP, a second or third PRS is always available allowing the vessel to continue to position itself safely. The PRS’s must use at least two differing technology types to prevent a common mode failure. An example of this is GNSS (Global Navigation Survey System) outages caused by environmental factors: the vessel will need another PRS that can continue to provide a robust position to the DP during these periods, for example SPRINT-Nav DP.

What is SPRINT-Nav DP?

SPRINT-Nav DP is a shallow water DP reference system which operates without needing a GNSS signal. When using SPRINT-Nav DP, there is also no need to deploy any other equipment such as transponders and reflectors as the system uses the seabed for reference. This increases the operational footprint of the vessel which until now has been limited in range, or weather conditions using existing sensors. Once the system has been given an initial starting position, it will measure its position change from this location, outputting a real-world position to the DP system.

When used independently, INS is an accurate reference for a short period of time, however, it is likely to drift over time if there is no aiding interfaced – combining DVL with INS helps to prevent this. The use of Sonardyne’s Syrinx DVL provides ultra-tight coupling of the DVL and INS data allowing for increased robustness and error management making the system ideal for DP operations.

We were the first to market a hybrid acoustic-inertial family of products for a variety of subsea applications and SPRINT-Nav now has a proven track record in subsea navigation. Our SPRINT-Nav family of all-in-one DVL-INS instruments has provided reliable navigation for ROVs, AUVs, and USVs for more than a decade. It is renowned for its performance and is installed on hundreds of vessels. Not only is SPRINT-Nav independent from GNSS, but it also has high accuracy and position update rate, comparable to GNSS.