The Charles Stark Draper Laboratory, Inc.

Michael E Ash

Richard T Martorana

Anthony S Kourepenis

Mitchell L Hansberry

Paul DeBitetto

Tom P Thorvaldsen

An omnidirectional borehole navigation system is provided that includes a housing that can be placed within the smaller diameter drill pipes used towards the bottom of a borehole, an outer gimbal connected to the housing, and at least two or more stacked inner gimbals that are nested in and connected to the outer gimbal, the inner gimbals each having an axis parallel to one another and perpendicular to the outer gimbal. The inner gimbals contain electronic circuits, gyros whose input axes span three dimensional space, and accelerometers whose input axes span three dimensional space. There are an outer gimbal drive system, an inner gimbal drive system for maintaining the gyro input axes and the accelerometer input axes as substantially orthogonal triads, and a processor responsive to the gyro circuits and the accelerometer circuits to determine the attitude and the position of the housing in the borehole.

Multi-gimbaled borehole navigation system

A compact navigation system for a rover is provided. The navigation system includes a housing configured to be transported by the rover; a gimbal system having two or more gimbals that includes at least an outer gimbal connected to the housing and an inner gimbal nested in and connected to the outer gimbal; a solid state three-axis gyro assembly mounted on the inner gimbal; a solid state three-axis accelerometer assembly mounted on the inner gimbal; a gyro logic circuit responsive to the three-axis gyro assembly for producing an inertial angular rate about each gyro input axis; an accelerometer logic circuit responsive to the three-axis accelerometer assembly for producing a non-gravitational acceleration along each accelerometer input axis; and a processor responsive to the gyro logic circuits and the accelerometer logic circuits for determining the attitude and the position of the housing to provide for long term accuracy of the attitude and the position for navigation of the rover.

Compact navigation system and method

An omnidirectional borehole navigation system is provided which features a housing for traversing a borehole; a gimbal system including at least one outer gimbal connected to the housing and at least one inner gimbal nested in and connected to the outer gimbal; a solid state three-axis gyro assembly mounted on the inner gimbal; a solid state three-axis accelerometer assembly mounted on the inner gimbal; gyro logic circuits on the inner gimbal responsive to the three-axis gyro assembly to produce the inertial angular rate about each gyro input axis; accelerometer logic circuits on the inner gimbal to produce the non-gravitational acceleration along each accelerometer input axis; and a microprocessor responsive to the gyro logic circuits and the accelerometer logic circuits for determining the attitude and the position and velocity of the housing in its borehole.

Borehole navigation system

An environmentally mitigated navigation system includes a thermal isolating chamber, an inertial measurement unit that can include individual gyroscopes and accelerometers for making inertial measurements, and a temperature control system; the temperature control system includes a thermoelectric cooling system, which in a powered mode maintains the inertial measurement unit at a substantially predetermined temperature, and a phase change device for maintaining the inertial measurement unit or inertial sensors at substantially a predetermined temperature in an unpowered mode; the phase change device substantially maintains the predetermined temperature by changing phase to define a stable temperature window for the inertial measurement unit or individual sensors to make inertial measurements during the unpowered mode as well as during the powered mode.

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Lexington, MA, United States of America

Michael E Ash