Abstract: An unmanned water vessel can include a body defining an internal volume and having a shape adapted to travel through water, with a front and a back; at least one directional device that is exposed to the flow of water past the vehicle when the vehicle travels in a forward direction, the directional device having a first position that provides an angle of attack through the water flow and a second position that provides a second angle of attack through the water flow; and a control system that provides commands to the at least one directional device in view of a starting point, an end point, and at least information about water flow expected to be encountered by the water vessel during travel.

Abstract: This invention relates in general to vibroseis and, more specifically, but not by way of limitation, to the enhancement and/or signal strength optimization of low frequency content of seismic signals for use in surveying boreholes and/or subsurface earth formations. In embodiments of the present invention, physical properties of a seismic vibrator may be analyzed and used to provide for determination of a driving force necessary to drive a reaction mass to produce a sweep signal with enhanced low frequency content for injection into the ground for vibroseis. In certain aspects, the physical properties may be considered independent of any geophysical properties related to operation of the seismic vibrator.