Use of acoustic navigation signals for simultaneous localization and sound-speed estimation

Area of Science:

• Oceanography
• Acoustics
• Navigation

Background:

• Lagrangian floats are crucial for oceanographic data collection.
• Acoustic navigation relies on precise sound speed estimation.
• Current methods assume a known, constant sound speed, limiting accuracy.

Purpose of the Study:

• To investigate the simultaneous estimation of sound speed and float location using low-resolution acoustic signals.
• To assess the impact of limited signal resolution on estimation accuracy.
• To develop methods for improving sound speed and localization accuracy.

Main Methods:

• Linearization of the acoustic navigation problem.
• Analytical solution for simultaneous estimation of float position and sound speed.
• Derivation of closed-form expressions for sound speed estimation errors.
• Exploitation of travel-time data from single and multiple floats.

Main Results:

• Sound speed estimation accuracy is influenced by float position and signal resolution.
• Utilizing data from multiple floats significantly improves sound speed and localization accuracy.
• Combining travel-time data from different locations enhances estimates for single floats.
• Numerical results validate theoretical error predictions and demonstrate method efficacy.

Conclusions:

• Low-resolution acoustic signals can be leveraged for simultaneous sound speed and float location estimation.
• Multi-float data fusion is key to overcoming limitations of low-resolution signals.
• The proposed method offers a pathway to more accurate underwater navigation and oceanographic measurements.