Devices for vectorially summing two signals. In a first embodiment (FIG. 3) the vectorial summation is implemented by a mechanical sin/cos mechanism in which a crank 22 drives two linear potentiometers 27 and 29, 90.degree. out of phase. In a second embodiment (FIG. 6) a polarized light resolver generates the sin and cos functions. In a third embodiment (FIG. 8) a printed circuit resolver generates the sin and cos functions.

A magnetic heading signal simulator that simulates the analog electrical signals representative of magnetic heading produced by a conventional flux value of an aircraft and provides the simulated signals to the magnetic heading reference system of the aircraft for test purposes receives digitally-encoded information representative of a desired value of heading and a rate at which that heading is to be reached. The simulator includes a logic circuit that receives the digital heading information f...

An aircraft heading reference system including a rate gyro for sensing the yaw rate .psi. of the aircraft and producing electrical signals representative thereof; a rate gyro for sensing the pitch rate .theta. of the aircraft and producing electrical signals representative thereof; an air speed sensor for sensing air speed .nu. of the aircraft and producing electrical signals representative thereof; a roll angle computer circuit responsive to the electrical signals representative of the yaw rate...

A heading detecting apparatus is attached to a moving object and includes a geomagnetic field sensor for detecting the direction of the earth's magnetic field in terms of orthogonal first and second signals and a computing circuit responsive to orthogonal first and second electric signals from the geomagnetic field sensor. In the computing circuit, when any one of the orthogonal first and second electric signals from the geomagnetic field sensor is a predetermined value, the value of the other e...

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 c...

A heading detecting apparatus of the type which is installed in a roof of a vehicle including a magnetic member (a steel body) capable of having a remanence and includes a heading sensor positioned near the magnetic member, whereby the apparatus detects the terrestrial magnetism and thereby detects the forward heading of the moving objects the apparatus includes a permeability member positioned between the magnetic member and the heading sensor so as to reduce the effect of the remanence of the ...

A course and heading computer for use with marine charts which includes a transparent planar baseplate having a semicircular edge at one end joined with rectangular edges at the opposite end, the straightedge parallel to the shorter dimension of the baseplate being equal in length to the diameter of the semicircle, a 360.degree. circular scale imprinted on the baseplate with its center at the center of the semicircle, and a printed scaled grid to assure quick, accurate alignment, on the marine c...

A heading tape for a curtain of the type which has part of the curtain extending upwardly from the suspension hooks. The curtain heading tape provided by the present invention prevents the upwardly extending part of the curtain from folding downwardly and resulting in an unsightly appearance. The curtain heading tape comprises core yarn disposed weft wise to give transverse stiffness to the tape, at least two spaced apart tubes forming a part of the tape and disposed warp-wise thereof for accomm...

A prawn/shrimp heading machine comprising a first pair of endless belts arranged with one run of one belt substantially parallel to but spaced apart from one run of the other belt and travelling in the same direction to enable the bodies of the prawns/shrimp to be located therebetween with the heads projecting beyond the peripheries of the first one pair of belts, and a second pair of endless belts arranged in a similar manner to engage the heads of the prawns/shrimp, the path of the second pair...

An inertial reference system for determining the attitude and rate of change of attitude of a vehicle such as an aircraft is disclosed. Redundancy of the inertial reference system may be accomplished by replacement of one of the fiber optic gyroscopes of an otherwise dual fiber optic gyros installation with a low-cost reference IMU. Failure detection and isolation of a fiber optic gyroscope system may be accomplished with a low-cost reference IMU rather than with an additional fiber optic gyrosc...