Abstract: An omnidirectional borehole navigation system comprising a housing for traversing a borehole; an outer gimbal connected to said housing and at least two or more stacked inner gimbals that are nested in and connected to said outer gimbal, said inner gimbals each having an axis parallel to one another and perpendicular to the outer gimbal; at least one inertial sensor located on each inner gimbal, the at least one inertial sensor including at least one gyro or accelerometer, the gyros having input axes that span three dimensional space and the accelerometers having input axes that span three dimensional space; one or more gyro circuits within the housing and responsive to the at least one gyro to produce the inertial angular rate about each gyro input axis; one or more accelerometer circuits within the housing and responsive to the at least one accelerometer to produce the non-gravitational acceleration along each accelerometer input axis; a processor responsive to said gyro circuits and said accelerometer circ

Abstract: 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.