Abstract: 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, pitch rate, and air speed for determining an electrical signal representative of the roll angle .phi. according to the expression:.psi.+.theta. tan .phi.=(tan .phi./cos .phi..multidot.(g/.nu.)and a yaw and pitch computer circuit, responsive to the pitch rate .theta., yaw rate .psi., and roll angle .phi. electrical signals for resolving the yaw and pitch rates about the roll angle .phi. to provide an electrical signal representative of the heading rate of the aircraft.

Abstract: A sun-sensing guidance system (10) for high-altitude aircraft (A) characterized by a disk-shaped body (14) mounted for rotation aboard the aicraft in exposed relation to solar radiation and having a plurality of mutually isolated chambers (28a, 28b, 32a, and 32b); each chamber of the plurality being characterized by an opening having a photosensor (34a, 34b, 36a, and 36b) disposed therein and arranged in facing relation with the opening for receiving incident solar radiation and responsively providing a voltage output, said photosensors being connected in paired relation through a bridge circuit (38) for providing heading error signals in response to detected imbalances in intensities of solar radiation incident on the photosensors of either pair of photosensors until a nulled relationship is achieved for the disk (14) to the source of radiation.

Abstract: Estimators of a vehicle's position and attitude with respect to the earth are generated continuously by integrating the outputs of translational and rotational accelerometers that are attached to the vehicle. These estimators are corrected by comparing them to corresponding reference dynamic variables measured independently by instruments onboard the vehicle. The estimators are modified by slowly responding servo loops to equal their corresponding reference variables. Differences between certain of the estimators and their corresponding reference dynamic variables are used in generating feedback signals for correcting other of the estimators. By combining various of the estimators, system outputs representing sideslip angle and change in cross-track velocity can be generated.

Abstract: An automatic rate range switching and control system adapts the full range of an analog output signal of a gyroscopic rate sensor to a range consistent with the precision conversion thereof into a digitally compatible signal. In a digital strapped down inertial reference system, for example, a plurality of strapped down, force-rebalanced rate sensors is used to sense aircraft body rates, wherein each gyro pick off signal is fed back to the gyro torquer in a manner to maintain the pick off signal essentially null, the torquer current signal thus being proportional to the sensed aricraft rate. The full range of the gyro's rate sensing capability may extend from zero to several hundred degrees per second. However, with the present invention, the switching and conversion of the analog rate signal into a digitally compatible signal is necessary only over a limited range.

Abstract: Terminal guidance of vehicles is accomplished by accurately determining true position and speed of the vehicle from terrain contour measurements and updating a dead reckoning navigation system with precision to permit navigation by following a programmed flight path. A narrow beam radar altitude sensor measures vehicle clearance altitudes and a reference altitude sensor measures the vehicle clearance above a reference level. These measurements are input to a digital processor for comparison to stored digital terrain contour reference data. Recursive data matching is performed in the digital processor by a nonlinear Kalman filtering technique to provide vehicle position and vehicle velocity correction signals to a navigation controller that generates steering commands to the vehicle control system. Three vehicle position and three vehicle velocity signals are generated and updated in the nonlinear Kalman filtering technique to give near real-time three dimensional position and velocity information.

Abstract: A control system for generating a control signal at a first station, transmitting the control signal to a second station, and processing the control signal at the second station to provide a controlled output. At least some of the processing equipment at the second station draws electrical power, and power for such purposes is generated by a generator located at the second station.

Abstract: Estimators of a vehicle's position and attitude with respect to the earth are generated continuously by integrating the outputs of translational and rotational accelerometers that are attached to the vehicle. These estimators are corrected by comparing them to corresponding reference dynamic variables measured independently by instruments onboard the vehicle. The estimators are modified by slowly responding servo loops to equal their corresponding reference variables. Differences between certain of the estimators and their corresponding reference dynamic variables are used in generating feedback signals for correcting other of the estimators. By combining various of the estimators, system outputs representing sideslip angle and change in cross-track velocity can be generated.

Abstract: The invention provides a method and device for producing substantially kinematic steering of a vessel in a yaw path having a given radius of curvature conforming with a predetermined control law. During the steady state phase of the yaw when there exist conditions for dealing with an easily controllable radius of curvature and in the vessel is steered by rudder deflection changes and by utilizing servo control methods in such a way that the radius of curvature of the vessel, which has been determined by instrument facilities aboard the vessel, follows a predetermined suitable program for the yaw curvature during the yaw.

Abstract: The automatic heading retention mode of operation of a flight control system for a rotary wing aircraft is discontinued and reestablished through the use of logic circuitry responsive to the bank angle of the aircraft and to the force applied to a control stick by the pilot. When the bank angle of the aircraft exceeds a preselected minimum and the lateral force applied to the cyclic pitch stick also exceeds a predetermined minimum the logic circuit operates to isolate the heading hold control from heading error signals and the heading retention mode of operation is automatically resumed when both of the bank angle and stick force fall below the preselected minimum levels. The invention may also encompass the application to the control mechanism of signals which will cause the aircraft to perform coordinated turns above a preselected minimum airspeed.

Abstract: An automatic drift corrector is provided for correcting the heading of an aircraft, boat, or other vehicle for drift. The drift corrector operates a synchro generator included in an automatic pilot system of the vehicle. The drift corrector includes a motor coupled to a control of the synchro generator, a variable voltage generator, a vane outside the vehicle and rotatable by drift of the vehicle to vary the voltage generator for generating a drift signal, an amplifier for applying the drift signal to the motor for causing the motor to operate the control of the synchro generator to correct for the drift, and a power supply for supplying power to the foregoing elements.

Abstract: A remote magnetic instrument, such as a compass, and a heading indicator, such as a heading gyro, are time shared in a dual channel gyro slaving amplifier with slaving and boot strap circuitry. The amplifier is a two function electronic device wherein the slaving circuit accepts heading error data from a heading gyro and provides separate channels of amplified information to slave drive the heading gyro. The second function of the amplifier is an electronic boot strap circuit to extract information from the heading gyro to drive a remote magnetic instrument. Each of the two functions shares equal time by operation of a time sharing switch with a timing signal provided from a ripple counter. The amplified information providing during the first function of the amplifier is a slaving signal representing heading correction generated by the slaving circuit responding to a heading error signal from the heading indicator.

Abstract: The circuit derives a rate signal from an a.c. signal proportional to attitude displacement provided, for example, from the synchro pickoff of a vertical gyroscope or an inertial navigation system, the pickoff receiving power from the aircraft a.c. power supply. The a.c. attitude signal is passed through a first bandpass filter tuned to the frequency of the power supply. The a.c. power supply signal is passed through a second bandpass filter identical to the first whose output is used as the reference signal for first and second identical demodulation circuits which include first and second matched low pass filters respectively. The filtered a.c. attitude signal is applied to the first demodulator circuit and the filtered power supply signal is applied to the second. The output of the first demodulator circuit is applied to a line voltage compensator and the output from the second demodulator circuit is applied to a d.c.

Abstract: A pair of electrostatic sensors are recessed in the outer wall of a superic ballistic body.The vertical electrostatic gradient in the atmosphere produces a voltage differential between the sensors when one sensor is higher than the other. Since the fixed geometrical relationship between the sensors is known, the magnitude and sign of the voltage differential can be correlated to the instantaneous attitude of the vehicle with respect to the earth's surface.

Abstract: The instant system describes a heading and attitude reference system for an aircraft in which slaving of the directional gyro to the magnetic compass and roll erection of the vertical gyro is cut off during turns which exceed a predetermined rate. A unique feature of the system is the manner in which the turn rate cutoff rate signal is generated from the directional gyro without incorporating either rate gyros or rate generators. The turn rate cutoff signal is generated from the directional gyro heading signal by converting the heading signal electrically into a signal proportional to turn rate. In one embodiment, the heading signal from the directional gyro which is representative of the heading shaft angle (.theta.) is converted into a plurality of signals proportional to the sine and cosine of shaft angle .theta.. These signals are first differentiated and then vector summed to produce a signal directly proportional to the rate of shaft rotation (d.theta.

Abstract: An improved second order gyroscopic attitude and heading reference system including separate variable time constant accelerometer integrators for independently controlling the velocity error signals associated with respective east and north acceleration signals to provide velocity damped output signals so that a high acceleration input signal of dubious accuracy will have minimal precessional authority while a lower acceleration input signal of greater accuracy will retain nominal control.

Abstract: A control system for hydrofoil craft is one in which control surfaces are moved automatically in response to signals derived from the motion of the craft to stabilize and control the craft. In such systems, a potentially dangerous condition can occur in case of a failure or malfunction in the roll control system. In order to prevent such conditions, two roll sensing devices are provided which normally generate identical signals to actuate the control surfaces to stabilize the rolling motion. In case a failure or malfunction, the signals provided by the two sensing devices become different and apparatus is provided to compare these signals and to respond to a difference in the signals to initiate landing of the craft rapidly and safely.