Demonstration of Spiral Wavefront Navigation on an Unmanned Underwater Vehicle

Experiments carried out at NUWC's Seneca Lake facility in the summer of 2020 demonstrate the efficacy of underwater navigation via a single spiral wavefront (SWF) acoustic beacon. An SWF beacon is a transducer array that has the capability of generating a spiral acoustic signal whose phase varies linearly with angular aspect along with a reference signal with constant phase. An unmanned underwater vehicle (UUV) operating in Seneca Lake under various channel conditions receives a regular signal from a fixed position single SWF beacon. The UUV's aspect relative to the beacon and its radial velocity can be determined by comparing the phase of the spiral signal to that of the reference signal. The SWF navigation solutions are compared to the UUVs inertial/GPS navigation. Advances in signal processing for the spiral wavefront navigation in multipath environments are detailed. An example of multipath performance from experimental data is shown.