Doppler Velocity Log Placement Effects on Autonomous Underwater Vehicle Navigation Accuracy

Doppler Velocity Logs (DVLs) provide an important correcting measurement to the Inertial Navigation Systems (INSs) of Autonomous Underwater Vehicles (AUVs). DVLs are typically co-located near the Inertial Measurement Unit (IMU) at the AUV's center of buoyancy (CB) to permit a direct correction of the AUV's linear velocities. However, recent research has demonstrated that mounting the DVL at a lever-arm offset from the CB changes the observability of vehicle states. This paper expands on previous research to explore the effects of DVL placement on AUV navigation accuracy in both loosely- and tightly-coupled frameworks. This paper finds that, in stark contrast to their standard placement, almost all practical AUVs could benefit from the DVL being mounted far from the CB to minimize navigation errors when integrated into a tightly-coupled framework. These results suggest that the DVL's mounting location should be considered during the design stages of an AUV due to its effect on navigation accuracy.