Abstract: An accelerometer arrangement and method are described for determining accelerations of an inground tool. First and second triaxial accelerometers are supported such that a normal sensing axis of the first triaxial accelerometer is at least generally orthogonal to the normal sensing axis of the second triaxial accelerometer for determining the accelerations along the three orthogonal axes based on a combination of sensing axis outputs from one or both of the triaxial accelerometers. A weaker sensing axis of one triaxial accelerometer can be supported at least approximately normal to a weaker sensing axis of another triaxial accelerometer such that the weaker axes are not used. The triaxial accelerometers can be supported such that one axis of one accelerometer can be redundant with respect to another axis of another accelerometer. One triaxial accelerometer can be mounted on a tilted plane with respect to another triaxial accelerometer.

Abstract: Discriminating between a cable locating signal and a false cable locating signal is described. A reference signal, which contains a locating signal frequency impressed on it, is transmitted in a way which provides for detection of a phase shift between the locating signal and the false locating signal. Based on the phase shift, a receiver is used to distinguish the locating signal from the false locating signal.

Abstract: A transmitter is powered by a regulated battery voltage and is installable in one of a plurality of different housings, each housing is characterized by a different design and each can form part of an inground tool for performing an inground operation in which a drill string extends from a drill rig to the inground tool. An antenna driver drives an antenna based on the regulated voltage to emanate an electromagnetic signal for remote reception. A controller limits power consumption from the regulated voltage so as not to exceed a power consumption threshold, irrespective of installation of the transmitter in any one of the housings when the transmitter would otherwise exhibit a different power consumption for each housing design. A corresponding method is described. Features relating to power consumption threshold modification based on temperature as well as mechanical shock and vibration are described.

Abstract: A transmitter for inground use controls a depth signal transmit power in relation to a data signal transmit power such that one reception range of the depth signal at least approximately matches another, different reception range of the data signal. A portable device can form a system with the transmitter in which the portable device scans a plurality of frequencies within at least one low frequency depth signal range to measure the electromagnetic noise at each one of the plurality of frequencies and identify at least one of the frequencies as a potential depth frequency for the transmitter. The portable device can include a dual mode filter having a rebar mode and a normal mode filter. The depth signal frequency is dynamically positionable in relation to low frequency noise.

Abstract: A portable locator includes a locator housing having a display head that supports a display. A GPS module includes a frame and an antenna arm extending from a side margin of the frame. The frame defines a display aperture such that the frame is removably installable on the display head of the portable locator with the display visible through the display aperture. An electrical interface provides for electrical communication with the portable locator with the frame removably installed thereon.

Abstract: A sonde is receivable in a housing of an inground tool for transmitting an electromagnetic locating signal. The sonde is configured for monitoring a cumulative active run-time of its operation and for external transfer of the cumulative active run-time. A receiver receives the cumulative active run-time and provides at least one indication based on the cumulative active run-time.

Abstract: An emergency collective actuator includes an actuator motor to produce an actuation force and an actuator linkage that directly engages a friction control lever that is pivotally supported on the collective stick of a helicopter to apply the actuation force directly to the friction control lever such that the actuation force initially disengages the friction control and then reduces the adjustable pitch toward a minimum collective pitch position. The actuator can include a clutch that slips to allow the pilot to overcome the actuation force and that slips responsive to an engagement of the friction control by the pilot, but otherwise the clutch co-rotates with the motor shaft to bias the adjustable pitch toward a minimum collective pitch position.

Abstract: A planning tool plans movement of a boring tool for an underground drilling operation. The planning tool includes one or more wheels for rolling on a surface of the ground along a path responsive to movement by an operator to characterize the surface contour and to generate guidance for the boring tool to reach a target position. Planning can additionally be based on waypoints. The planning tool can be rolled unidirectionally or bidirectionally to characterize the surface contour. Bidirectional movement cancels accelerometer fixed bias. Path stitching is used to plan around obstacles. The planning tool can facilitate tracker placement. The planning tool can collect noise information for frequency selection purposes. A described technique maximizes linear drilling in an underground plan. Compensation and/or warnings are provided for unsteady, fast and slow movement of the planning tool while measuring the surface contour.

Abstract: A portable device is described for use with a system in which a transmitter signal is transmitted by a transmitter from within the ground during an operational procedure. The portable device is configured for measuring electromagnetic noise. An extension leg is removably attachable to the portable device and supports a measurement wheel at a distal end such that the electromagnetic noise is measured on a measurement path along which the measurement wheel is rolled for use in selecting a transmission frequency for the transmitter signal.

Abstract: An accelerometer arrangement and method are described for determining accelerations of an inground tool. First and second triaxial accelerometers are supported such that a normal sensing axis of the first triaxial accelerometer is at least generally orthogonal to the normal sensing axis of the second triaxial accelerometer for determining the accelerations along the three orthogonal axes based on a combination of sensing axis outputs from one or both of the triaxial accelerometers. A weaker sensing axis of one triaxial accelerometer can be supported at least approximately normal to a weaker sensing axis of another triaxial accelerometer such that the weaker axes are not used. The triaxial accelerometers can be supported such that one axis of one accelerometer can be redundant with respect to another axis of another accelerometer. One triaxial accelerometer can be mounted on a tilted plane with respect to another triaxial accelerometer.

Abstract: An apparatus and method are used in conjunction with a system for performing horizontal directional drilling, the system including a drill string extending from a drill rig to a boring tool such that the boring tool is steerable based on a roll orientation. The system also includes an arrangement for generating steering commands for guiding the boring tool to a target position. Responsive at least in part to the steering commands, a display is configured to selectively indicate each of a rotate command, a push command and a spin command. A steering indicator is described which indicates a current roll orientation of the boring tool. A 3-D grid can be animated and centered on either a steering or target indicator. Rounding of a steering command ratio can limit the display of target roll orientations to only those that a given boring tool transmitter is capable of sensing and indicating.

Abstract: A transmitter for inground use controls a depth signal transmit power in relation to a data signal transmit power such that one reception range of the depth signal at least approximately matches another, different reception range of the data signal. A portable device can form a system with the transmitter in which the portable device scans a plurality of frequencies within at least one low frequency depth signal range to measure the electromagnetic noise at each one of the plurality of frequencies and identify at least one of the frequencies as a potential depth frequency for the transmitter. The portable device can include a dual mode filter having a rebar mode and a normal mode filter. The depth signal frequency is dynamically positionable in relation to low frequency noise.

Abstract: A housing defines a through passage along its length and is configured to support a group of electrical isolators surrounding the through passage to form an electrically isolating break in a drill string such that each isolator of the group of isolators is subject to no more than a compressive force responsive to extension and retraction of the drill string. The housing defines a housing cavity to receive an electronics package having a signal port and is configured for electrical connection of the signal port across the electrically isolating break. A housing lid can cooperate with a main housing body to define elongated slots for purposes of enhancing the emanation of a locating signal. A housing arrangement can support electrical connections from an electronics package to bridge an electrically isolating gap.

Abstract: Generally, a sonde, associated components and methods are described which can be used in conjunction with an inground tool having an inground tool housing that defines an inground tool cavity such that the inground tool cavity is exposed to an ambient pressure environment which surrounds the inground tool during an inground operation. A sonde housing assembly includes an exterior configuration that is receivable within the inground tool cavity. The sonde housing assembly at least partially defines a sonde interior and is further configured for receiving the pressure sensor body of a pressure sensor in a pressure sealed engagement. A sonde electronics package is supported within the sonde interior and is at least configured to receive the pressure signal and transfer a corresponding pressure signal from the sonde.

Abstract: A boring tool that is moved by a drill string to form an underground bore. A transmitter transmits a time varying dipole field as a homing field from the boring tool. A pitch sensor detects a pitch orientation of the boring tool. A homing receiver is positionable at a target location for detecting the homing field to produce a set of flux measurements. A processing arrangement uses the pitch orientation and flux measurements with a determined length of the drill string to determine a vertical homing command for use in controlling depth in directing the boring tool to the target location such that the vertical homing command is generated with a particular accuracy at a given range between the transmitter and the homing receiver and which would otherwise be generated with the particular accuracy for a standard range, different from the particular range. An associated system and method are described.

Abstract: A helicopter autopilot system includes an inner loop for attitude hold for the flight of the helicopter including a given level of redundancy applied to the inner loop. An outer loop is configured for providing a navigation function with respect to the flight of the helicopter including a different level of redundancy than the inner loop. An actuator provides a braking force on a linkage that serves to stabilize the flight of the helicopter during a power failure. The actuator is electromechanical and receives electrical drive signals to provide automatic flight control of the helicopter without requiring a hydraulic assistance system in the helicopter. The autopilot can operate the helicopter in a failed mode of the hydraulic assistance system. A number of flight modes are described with associated sensor inputs including rate based and true attitude modes.

Abstract: A boring tool is movable through the ground. A transmitter supported by the boring tool transmits an electromagnetic homing signal. A portable device monitors the electromagnetic homing signal and receives the electromagnetic homing signal in a homing mode for guiding the boring tool to a target position. A processor generates steering commands for guiding the boring tool based on a bore plan in a steering mode such that at least some positional error is introduced without using the electromagnetic homing signal. Switching from the steering mode to the homing mode is based on monitoring of the electromagnetic homing signal as the boring tool approaches the portable device to then guide the boring tool to the target position location in compensation for the positional error. Intermediate target positions are described as well as guiding the boring tool based on the homing signal so long as the portable device receives the signal.

Abstract: A device rotates at least one static magnetic field about an axis, producing a rotating magnetic dipole field, and is movable in relation to the surface of the ground. The field is periodically sensed using a receiver to produce a receiver output responsive to the field. A positional relationship between the receiver and the device is monitored using the output. In one aspect, changing the positional relationship, by moving the device nearer to a boring tool which supports the receiver, causes an increase in accuracy of depth determination. In another aspect, determination of an actual overhead position of the boring tool, and its application, are described. Use of a plurality of measurements over at least one-half revolution of each magnet is disclosed. Establishing a surface radial direction toward a boring tool and resolution of multi-valued parameters is described. Calibration techniques, as well as a three transmitter configuration are also described.

Abstract: Systems, apparatus and methods are described for purposes of initiating a response to detection of an adverse operational condition involving a system including a drill rig and an inground tool. The response can be based on an uphole sensed parameter in combination with a downhole sensed parameter. The adverse operational condition can involve cross-bore detection, frac-out detection, excessive downhole pressure, a plugged jet indication and drill string key-holing detection. A communication system includes an inground communication link that allows bidirectional communication between a walkover detector and the drill rig via the inground tool. Monitoring of inground tool depth and/or lateral movement can be performed using techniques that approach integrated values. Bit force based auto-carving is described in the context of an automated procedure.

Abstract: A transmitter for inground use controls a depth signal transmit power in relation to a data signal transmit power such that one reception range of the depth signal at least approximately matches another, different reception range of the data signal. A portable device can form a system with the transmitter in which the portable device scans a plurality of frequencies within at least one low frequency depth signal range to measure the electromagnetic noise at each one of the plurality of frequencies and identify at least one of the frequencies as a potential depth frequency for the transmitter. The portable device can include a dual mode filter having a rebar mode and a normal mode filter. The depth signal frequency is dynamically positionable in relation to low frequency noise.