Abstract: Land vehicle navigation apparatus combining an inertial angular rate sensor having a sensitive axis, with an inertial acceleration or tilt sensor having at least two sensitive axes, these sensitive axes having a known relationship to the inertial angular rate sensor's sensitive axis. Also provided is circuitry to accept from an external source an initial input valve (or self initialization, by rotary multiple positioning) of the vehicle's azimuthal orientation angles, roll, pitch, and azimuth, with respect to an Earth-fixed coordinate set as the land vehicle travels over the Earth surface. Changes to the azimuth angle during travel are determined by integration of the output of the inertial angular rate sensor.

Abstract: A land vehicle navigation apparatus incorporates an inertial angular rate sensor on the vehicle and having a sensitive axis, and an inertial acceleration or tilt sensor having at least two sensitive axes; the latter two sensitive axes are typically located at the vehicle in a plane parallel to the Earth's surface; and a rotary drive is operatively connected to the sensors to rotate them about an axis extending generally at the vehicle in a plane parallel to the Earth's surface; and, circuitry is operatively connected with the sensors to determine three vehicle orientation angles, roll, pitch, and azimuth, with respect to an Earth-fixed coordinate set at a first location, and also to determine the three vehicle orientation angles as the land vehicle travels over the Earth surface; and changes to the azimuth angle during travel are determined by integration of the output of the rate sensor; also, the sensor, drive and circuitry are typically carried by the vehicle.

Abstract: A borehole survey apparatus includes an angular rate sensor, a tilt sensor, a rotary drive to rotate the sensors about an axis extending in the direction of the borehole, circuitry connected with said sensors to determine the azimuthal direction of tilt of the borehole at a first location therein, drive control circuitry and a switch operatively connected with the sensors whereby they may be connected in feedback relation with the rotary drive so that an axis defined by a support for the rate sensor is maintained at predetermined orientation relative to horizontal during travel of the apparatus in a borehole relative to the first location, and integration circuitry connected with the rate sensor whereby changes in borehole alignment during travel may be determined.

Abstract: A borehole survey apparatus including(a) angular rate sensor means having a sensitive axis,(b) tilt sensor means,(c) a rotary drive operatively connected to said (a) and (b) sensor means to rotate same about an axis extending generally in the direction of the borehole,(d) and circuitry operatively connected with said (a) and (b) sensor means to determine the azimuthal direction of tilt of the borehole at a first location therein, said (a) sensor means also connected in feedback relation with the drive whereby the sensitive axis of the (a) sensor means is maintained at a predetermined orientation relative to horizontal during travel of said apparatus in the borehole relative to said first location, and whereby changes in borehole alignment during said travel may be determined.

Abstract: A borehole mapping apparatus which employs a ring laser gyroscope. The path of the laser is defined by looping paths of laser beam travel having long and short stretches of travel. The ratio of the stretches being substantially greater than two.

Abstract: The invention relates generally to mapping or survey apparatus and methods, and more particularly concerns efficient transmission of survey signals or data from depth level in a borehole or well to the well surface, for analysis, display or recordation; further it concerns efficient transmission of command data from a surface computer unit to the survey tool at depth level in a borehole or well for control of instrumentation operating modes, operating characteristics, or diagnostic purposes; and further it concerns supply of DC power downwardly to the instrumentation via a wireline by which such command signal and survey data or signals may be transmitted upwardly or downwardly respectively.

Abstract: This invention relates to mapping or survey apparatus and methods, and more particularly concerns derivation of the azimuth output indications for such apparatus in a borehole from the outputs or output indications of either an inertial angular rate vector sensor (or sensors) and an acceleration vector sensor (or sensors), or a magnetic field vector sensor (or sensors), and from the outputs of an acceleration vector sensor (or sensors). At least one of such sensors in any instrument may be canted relative to the borehole axis. Borehole tilt is also derived.

Abstract: A well mapping apparatus comprises:(a) a magnetic field sensing device whose output is proportional to a local magnetic field vector,(b) an acceleration sensing device whose output is proportional to a local gravity vector,(c) the devices supported for rotation about a common axis, in a borehole,(d) the outputs being usable in the determination of azimuth and inclination of the borehole.

Abstract: Bore-hole mapping, or surveying, or tool steering in a bore-hole is accomplished using selected combinations of sensors, with sensor signal compensation being provided, in the hole or at the surface. Typical sensors include an angular rate sensor or sensors, a linear acceleration sensor or sensors, and an angular acceleration sensor or sensors. The sensor group is typically rotated in the bore-hole, and the sensors may have selected sensitive axis angularity relative to the travel axis in the bore-hole.

Abstract: A borehole survey method employs a first sensor for measuring angular rate, and a second sensor or sensors for sensing tilt, and a rotary drive for the first and second sensors, and includes the steps:(a) operating the drive and the first and second sensors at a first location in the borehole to determine the azimuthal direction of tilt of the borehole at such location,(b) then traveling the first and second sensors and the drive lengthwise of the borehole away from the location, and operating the drive and at least one of the first and second sensors during such traveling to determine changes in borehole alignment during such traveling.

Abstract: A borehole mapping and/or navigational instrument includes a carrier movable lengthwise in the borehole; structure on the carrier defining an axis of rotation; and a tilt sensitive device rotatable about the axis of rotation, that device having a tilt sensitive axis with components along the axis of rotation and along perpendiculars to that axis. One or more angular rate sensors may be provided to be rotatable about the axis of rotation.

Abstract: The invention concerns efficient transmission of borehole survey signals or data from depth level in a borehole or well to the well surface, for analysis, display or recordation; further it concerns supply of DC power downwardly to the instrumentation via the same wireline via which such survey data or signals are transmitted upwardly.

Abstract: This invention relates to mapping or survey apparatus and methods, and more particularly concerns derivation of the azimuth output indications for such apparatus in a borehole from the outputs or output indications of either an inertial angular rate vector sensor (or sensors) and an acceleration vector sensor (or sensors), or a magnetic field vector sensor (or sensors), and from the outputs of an acceleration vector sensor (or sensors). Borehole tilt is also derived.

Abstract: Survey apparatus and method employs a free gyroscope for fast determination of azimuth, free gyroscope alignment being periodically corrected by a rate gyroscope which is periodically rotated for accurate azimuth determination. An accelerometer is also usable in conjunction with the gyroscopes for tilt determination. More generally, method and means is provided for calibrating (initially or periodically) an angle or position reference device.

Abstract: A method of determining azimuth involves use of an angular accelerometer, and includes:(a) rotating the accelerometer about a first axis while the accelerometer is carried on a body which is itself rotating about a second axis, and(b) detecting the accelerometer output of the accelerometer which is caused by said rotation.The accelerometer may for example be rotated in a bore hole in the earth, with the first axis extending in the direction of the hole.

Abstract: A borehole mapping and navigational instrument which travels up and down in a well. The instrument includes a housing which supports at least a rate gyroscope, accelerometer, and an electric motor to rotate the accelerometer about an axis which is canted about the axis of the housing. Since the accelerometer is rotated, its tilt sensitive axis then effectively has components along the X and Y directions normal to the Z axis, whereby components along all three axis are provided.

Abstract: Mapping apparatus comprises:(a) a gyroscope and a carrier frame therefor,(b) the gyroscope characterized as having a spinning rotor and torsion structure defining a gimbal, and wherein the rotor spin frequency has a predetermined relation to a resonant frequency of said structure,(c) the gyroscope further characterized as having two input axes, and an output axis about which the spin rotor rotates,(d) drive means operatively connected with said frame to rotate the frame about one of said axis, and(e) the gyroscope having means to detect rotor pivoting about one of said two input axes in response to said rotation of the frame.A second gyroscope may be employed, with its frame. rotated by the same drive means; and the output axes of the two gyroscopes are typically orthogonally related.

Abstract: Survey apparatus and method employs one or more rate gyroscopes having spin axis components directed along an instrument travel axis and in also in directions normal to the travel axis, so that when the gyroscope or gyroscopes are rotated, the earth's rate of rotation will be detected, at all latitudes and at all instrument attitudes.

Abstract: Survey apparatus and method employs a free gyroscope for fast determination of azimuth, free gyroscope alignment being periodically corrected by a rate gyroscope which is periodically rotated for accurate azimuth determination. An accelerometer is also usable in conjunction with the gyroscopes for tilt determination.