Abstract: Apparatus and method for determining the azimuth (heading), pitch and roll which include a magnetometer-type sensor providing signals measured in three axes relative to a reference frame, and coil elements wound around the magnetometer which selectively impose specific magnetic fields about the sensor. Three axes field components of the magnetic field are measured from the sensor with and without the selective energization of the magnetic coils and stored, from which the azimuth, pitch and roll are calculated. Furthermore, quadrant correction is applied such that a unique reading is produced for all angles through 360.degree. of azimuth, pitch or roll.

Abstract: Apparatus and method for determining the azimuth (heading), pitch and roll which include a magnetometer-type sensor providing signals measured in three axes relative to a reference frame, and coil elements wound around the magnetometer which selectively impose specific magnetic fields about the sensor. Three axes field components of the magnetic field are measured from the sensor with and without the selective energization of the magnetic coils and stored, from which the azimuth, pitch and roll are calculated. Furthermore, quadrant correction is applied such that a unique reading is produced for all angles through 360.degree. of azimuth, pitch or roll.

Abstract: A communication system for a seismic streamer by which all power and data signals are inductively coupled to the cable leveling devices or instrument pods disposed along the streamer cable. A high permeability ring of magnetic material is dispose around the streamer, and a coil is wound around a segment of the core and connected to circuitry within the bird. The coil can be part of a resonant circuit. Power signals transmitted along the streamer are inductively coupled via the ring core and associated coil to each bird to provide charging of a battery source in the bird. Control signals transmitted along the streamer are coupled via the ring core and coil to the electronics via the ring core and coil to the streamer for transmission to a receiving site. Alternative embodiments are also disclosed in which inductive coupling structures include a portion within the streamer in efficient coupling relationship for power and data transmission.

Abstract: A method for compensating for pitch and roll misalignment in 3-axis magnetometer-type compasses wherein the magnetometer during factory calibration is subjected to magnetic fields corresponding to at least two different latitudes, and correction coefficients for the measured x and y (or horizontal) magnetic field components are derived from signals derived from the z axis (or vertical) magnetic field sensor. The correction coefficients are permanently stored in the compass to provide a heading corrected for internal pitch and roll misalignment of the magnetometer field measuring elements relative to the true vertical that would normally cause errors in azimuth with changes in latitude. No further correction or misalignment is necessary in the field for compass use.

Abstract: The present disclosure is directed to a controlled reflection readout for information displays or targets such as digital or instrumentation panels for such apparatus as computers, compasses, watches, clocks and consoles wherein the display is not placed normal to the viewing plane and cannot be read at 90.degree. to the display. The display or specular transparent window is inclined to the line of sight and glare shielding means which extends forwardly from the top of the display or target to prohibit reading the display at a right angle thereto whereby reflections from the sun or lights in a room will interfere with reading through the optically transparent window in front of the target or display.

Abstract: An alphanumeric display system including an array of preferably 14 or alternatively, 15 light-emitting elements capable, when selectively activated, of legibly forming all numerals, and various alphabet letters and/or mathematical and punctuation symbols. The arrays disclosed are characterized by the arrangement of the light-emitting elements in a closely nested relation to form horizontal rows and columns inclined to both the right and the left at 60.degree. with respect to the horizontal. A solid state system for selectively energizing the light-emitting elements is disclosed.

Abstract: The present disclosure is directed to a controlled reflection readout for light emitting information displays for such apparatus as computers, compasses, watches, clocks and consoles wherein the light emitting display is not placed normal to the viewing plane and cannot be read at 90.degree. to the display. The light emitting display is inclined to the line of sight and glare shielding means extends forwardly from the top of the display to prohibit reading the display at a right angle thereto whereby reflections from the sun or lights in a room will interfere with reading through the optically transparent window in front of the light emitting display.

Abstract: An alphanumeric display system including an array of sixteen electrically energizable, light-emitting elements capable, when selectively energized, of forming legibly all numerals and a substantial number of upper and lower case alphabet letters and/or mathematical and punctuation symbols. A similar array is disclosed having a maximum of twenty four light-emitting elements and capable of providing all numerals, upper and lower case alphabet letters and a majority of the symbols employed for punctuation and in mathematics. Both of the arrays disclosed are characterized by arrangement of the light-emitting elements in closely nested relation to form horizontal rows and columns inclined to the right and left at 60.degree. with respect to the horizontal. A solid state system including light-emitting diodes and switching transistors is disclosed.