Survey apparatus and method employing canted tilt sensor

Claim 2

In a borehole navigation apparatus, the combination comprising (a) a carrier movable lengthwise in the borehole, (b) means on the carrier defining an axis of rotation, (c) a tilt sensitive device located interiorly of the carrier and having a sensitive axis for sensing tilt, said axis extending in a cant direction having components respectively along said axis of rotation and also along perpendiculars to said axis of rotation, such device being rotatable about said axis of rotation, (d) drive means on the carrier for rotating said device about said axis of rotation, the extent of said cant remaining fixed during said rotation, and (e) said device having an output which varies as a function of said rotation, and including means for processing said output.

Claim 3

The combination of claim 1 wherein said carrier defines an axis of travel lengthwise of the borehole, and said axis of rotation is parallel to said axis of travel.

Claim 4

The combination of claim 2 wherein said axis of rotation is coincident with said axis of travel.

Claim 5

The combination of claim 1 wherein said device has an output which varies as a function of said rotation, and including means for processing said output.

Claim 6

In a borehole navigation apparatus, the combination comprising (a) a carrier movable lengthwise in the borehole, (b) means on the carrier defining an axis of rotation, and (c) a tilt sensitive device located interiorly of the carrier and having a sensitive axis for sensing tilt, said sensitive axis extending in a cant direction having components respectively along said axis of rotation and also along a perpendicular to said axis of rotation, such device being rotatable about said axis of rotation, (d) and a second tilt sensitive device on the carrier and having a sensitive axis for sensing tilt, said sensitive axis of said second device extending in a cant direction having components respectively along said axis of rotation and also along a perpendicular to said axis of rotation, such device being rotatable about said axis of rotation, said two sensitive axes of said two devices respectively being orthogonally related relative to said axis of rotation.

Claim 7

In a borehole navigation apparatus, the combination comprising (a) a carrier movable lengthwise in the borehole, (b) means on the carrier defining an axis of rotation, and (c) a tilt sensitive device located interiorly of the carrier and having a sensitive axis for sensing tilt, said sensitive axis extending in a cant direction having components respectively along said axis of rotation and also along a perpendicular to said axis of rotation, such device being rotatable about said axis of rotation, (d) and a second tilt sensitive device on the carrier and having a sensitive axis for sensing tilt, said sensitive axis of said second device extending in a cant direction having components respectively along said axis of rotation and also along a perpendicular to said axis of rotation, such device being rotatable about said axis of rotation, said two sensitive axes of said two devices respectively being orthogonally related relative to said axis of rotation.

Claim 8

The combination of claim 5 including drive means on the carrier connected to simultaneously rotate said devices about said axis of rotation while their sensitive axes remain orthogonally related as aforesaid, one of said devices located above the other.

Claim 9

The combination of claim 6 wherein the devices have outputs which vary as a function of said rotation, and including means for processing said outputs for comparison.

Claim 10

In navigation apparatus, the combination comprising (a) a carrier movable lengthwise, (b) means on the carrier defining an axis of rotation, said means including a drive, (c) a tilt sensitive device located interiorly of the carrier to be rotated about said axis by said drive, said device having a sensitive axis for sensing tilt, said sensitive axis extending in a cant direction having components respectively along said axis of rotation and also along perpendiculars to said axis of rotation, the extent of said cant remaining fixed and predetermined during such rotation, (d) said device having an output which varies as a function of said rotation, and including means for processing said output.

Claim 11

In navigation apparatus, the combination comprising (a) a carrier movable lengthwise, (b) means on the carrier defining an axis of rotation, said means including a drive, (c) a tilt sensitive device located interiorly of the carrier to be rotated about said axis by said drive, said device having a sensitive axis for sensing tilt, said sensitive axis extending in a cant direction having components respectively along said axis of rotation and also along perpendiculars to said axis of rotation, the extent of said cant remaining fixed and predetermined during such rotation, (d) said device having an output which varies as a function of said rotation, and including means for processing said output.

Claim 12

The apparatus of claim 1 including a second tilt sensitive device on the carrier and rotatable about said axis of rotation.

Claim 13

The apparatus of claim 9 wherein said second tilt sensitive device has a sensitive axis which is tilted in a cant direction orthogonally related to the sensitive axis of said first device.

Claim 14

The apparatus of claim 9 wherein said devices comprise accelerometers.

Claim 15

In a borehole navigation apparatus, the combination comprising (a) a carrier movable lengthwise in the borehole, (b) means on the carrier defining an axis of rotation, (c) a first tilt sensitive device located interiorly of the carrier and having a sensitive axis for sensing tilt, said sensitive axis extending in a cant direction having components respectively along said axis of rotation and also along a perpendicular to said axis of rotation, such device being rotatable about said axis of rotation, (d) and a second tilt sensitive device on the carrier and having a sensitive axis for sensing tilt, said second device being rotatable relative to said axis of rotation, said two sensitive axes of said two devices extending in non-parallel relation.

Claim 16

In a borehole navigation apparatus, the combination comprising (a) a carrier movable lengthwise in the borehole, (b) means on the carrier defining an axis of rotation, (c) a first tilt sensitive device located interiorly of the carrier and having a sensitive axis for sensing tilt, said sensitive axis extending in a cant direction having components respectively along said axis of rotation and also along a perpendicular to said axis of rotation, such device being rotatable about said axis of rotation, (d) and a second tilt sensitive device on the carrier and having a sensitive axis for sensing tilt, said second device being rotatable relative to said axis of rotation, said two sensitive axes of said two devices extending in non-parallel relation.

Claim 17

The combination of claim 12 including drive means on the carrier connected to simultaneously rotate said devices about said axis of rotation while their sensitive axes remain related to aforesaid, one of said devices located above the other.

Claim 18

The combination of claim 13 wherein the devices have outputs which vary as a function of said rotation, and including means for processing said outputs for comparison.

Claim 19

The combination of claim 12 wherein said devices comprise accelerometers.

Claim 20

In a borehole navigation apparatus, the combination comprising (a) a carrier movable lengthwise in the borehole, (b) means on the carrier defining an axis of rotation, (c) a first tilt sensitive device located interiorly of the carrier and having a sensitive axis for sensing tilt extending in a first cant direction having components respectively along said axis of rotation and also along perpendiculars to said axis of rotation, said first device being rotatable about said axis of rotation, (d) a second tilt sensitive device located interiorly of the carrier and having a sensitive axis for sensing tilt extending in a second cant direction having components respectively along said axis of rotation and also along perpendiculars to said axis of rotation, said second device being rotatable about said axis of rotation, said second cant direction being out of parallel with respect to said first cant direction, and (e) drive means on the carrier for rotating said devices about said axis of rotation, the relationships of cants of said device sensitive axes, remaining known during said rotation.

Claim 21

In a borehole navigation apparatus, the combination comprising (a) a carrier movable lengthwise in the borehole, (b) means on the carrier defining an axis of rotation, (c) a first tilt sensitive device located interiorly of the carrier and having a sensitive axis for sensing tilt extending in a first cant direction having components respectively along said axis of rotation and also along perpendiculars to said axis of rotation, said first device being rotatable about said axis of rotation, (d) a second tilt sensitive device located interiorly of the carrier and having a sensitive axis for sensing tilt extending in a second cant direction having components respectively along said axis of rotation and also along perpendiculars to said axis of rotation, said second device being rotatable about said axis of rotation, said second cant direction being out of parallel with respect to said first cant direction, and (e) drive means on the carrier for rotating said devices about said axis of rotation, the relationships of cants of said device sensitive axes, remaining known during said rotation.

Claim 22

The combination of claim 16 wherein said devices comprise accelerometers or the like.