Abstract: A sonde array that is useful in locating buried utilities includes at least three substantially mutually orthogonal antennas. Each antenna includes a substantially cylindrical ferromagnetic core, an insulating layer surrounding the core, and a length of a conductor wrapped around the insulating layer to form a coil. The coils of the antennas are substantially identical.

Abstract: A deep submersible light includes a body defining a hollow interior and a solid state light source such as a plurality of high brightness LEDs mounted in the interior of the body. A transparent window is mounted over the LEDs. The space between the transparent window and the LEDs is filled with an optically transparent fluid, gel, or grease, which allows light to pass through and ambient water pressure to pass in, thus pressure compensating the LEDs by allowing them to see ambient water pressure. The transparent window is mounted in the body for reciprocation in both a forward direction and a rearward direction to accommodate volumetric changes in the compensating fluid, gel, or grease caused by changes in temperature and water pressure as the manned or remotely piloted submarine travels from the sea surface to deep ocean depths.

Abstract: At least one antenna array including three mutually orthogonal antennas each sharing a common center point senses an electromagnetic signal emitted by a buried object such as a utility line, pipe or sonde. A circuit at least partially mounted in a housing is connected to the array and determines a location of the buried object by measuring signal strength and field angles in three dimensions without having to align the antenna array relative to the buried object while eliminating nulls and false peaks. A graphical user interface (GUI) has user-friendly icons, symbols, menus, numbers and graphical and auditory representation of signal strength. A SEARCH view indicates signal strength by showing a rotating strength indicator, a trace mode MAP view in which line location is shown by a line that moves side-to-side, and a sonde mode MAP view in which sonde location is shown by a moving line, pole and equator.

Abstract: A pre-amplifier circuit for connection to an antenna of a human-portable locator includes a differential amplifier/mixer pair and means for allowing a common-mode “phantom” signal to modulate a transfer function of the differential amplifier/mixer pair. The common-mode phantom signal modulates the transfer function of the differential pre-amplifier “onboard” the antenna without the usual requirement for onboard power supply and signal oscillator. This technique uses the same electronic components to provide both pre-amplification and mixing functions, thereby improving circuit performance-to-cost ratio, reducing mixer power consumption, situating the necessary signal oscillator remotely from the mixer, and greatly improving the available system bandwidth by limiting spectral transmission demands to the mixed signal bandwidth alone.