A method of operating a communications device to maintain a position fix of the communications device includes obtaining a position fix using a position determination capability of the device, such as a global positioning system capability. The method further includes emitting a first acoustic signal, and recording a baseline acoustic signature in response to the emission of the first acoustic signal. The method further includes emitting an additional acoustic signal and recording an additional acoustic signature resulting from the emission of the additional acoustic signal, comparing the baseline acoustic signature with the additional acoustic signature, and estimating, based at least in part on the comparison of the baseline and additional acoustic signatures, whether the communications device has moved between the recordings of the baseline and additional acoustic signatures.