Single beacon underwater navigation method in the presence of unknown effective sound velocity, clock drift and inaccurate beacon position

Existing single beacon navigation systems commonly require precise known Effective Sound Velocity (ESV) and beacon position, as well as clock synchronization between the beacon and the hydrophone. However, these conditions are often difficult to guarantee in practical applications. Unknown clock drift, inaccurate ESV and beacon position will affect the range measurement precision, and consequently induce large localization errors. To eliminate the influence of above mentioned factors on the positioning accuracy, this paper proposes a new method of single beacon navigation. It treats clock drift, ESV and beacon position as unknown system parameters, and estimates them by the Expectation Maximization (EM) method. The advantages of new method are verified by field data. Numerical examples indicate that the method has better navigation performance than existing state-of-the-art methods in the presence of unknown clock-drift, ESV and beacon position setting error.