Abstract: An anti-log power amplifier for energizing a reversible electric motor of an electrically assisted power steering system for an automotive vehicle. The power amplifier has a preamplifier which amplifies the output signal of a torque sensor detecting the torque applied to the vehicle's steering wheel, an anti-log signal generator exponentially modifying the amplified output signal, a pulse width modulator converting the exponentially modified signal to a pair of complementary pulse width signals, and a pair of bridged power amplifiers for energizing the reversible electric motor in response to the complementary pulse width signal. The bridged power amplifiers are further responsive to the exponentially modified signal for increasing the electrical power delivered to the reversible electric motor under high torque loads.

Abstract: The flight path transition control apparatus provides a roll attitude command to control the aircraft to execute an exponential transition path to a predetermined course in accordance with the exponential control law Y+KY where Y is the lateral displacement of the aircraft from the predetermined course, Y is the rate of change of the lateral displacement and K is a time constant of the system. A predictive roll command .phi..sub.p is generated in accordance with ##EQU1## where V.sub.g is the aircraft ground speed,TAE is the track angle error of the aircraft with respect to the predetermined course,TAE.sub.0 is the track angle error of the aircraft with respect to the predetermined course at capture maneuver initiation,g is the gravitational constant, andt is the elapsed time following capture initiation.The predictive roll command .phi..sub.p is combined with the exponential control law to provide the aircraft roll attitude command .phi..sub.c =.phi..sub.

Abstract: An improved steering control system is provided for improving the handling qualities of hydrofoil craft during takeoff. In steering control systems for hydrofoils, the craft is banked by operation of control surfaces and the rudder is turned in the corresponding direction to coordinate the turn. To improve the handling qualities and maneuverability during the period of acceleration from hull-borne to foil-borne operation, the steering control system is modified during this period by decreasing the gain of the control loop for the control surfaces and by increasing the gain of the control loop for the rudder. A lag filter is also introduced into both loops.

Abstract: A yaw axis stability and command augmentation system (SCAS) particularly applicable to STOL type aircraft includes three primary control terms proportional to side slip angle, side slip angle rate and rudder pedal force, wherein side slip angle rate is synthesized from measures of yaw rate, bank angle and lateral acceleration. These primary system feedback terms are supplied to the rudder electro-hydraulic secondary actuator which is positioned in accordance with their sum. The system serves to provide improved automatic damping of the Dutch roll modes, to suppress aircraft motion transients in yaw and roll under engine failure situations, to provide automatic turn-coordination in maneuvering flight, and to provide a side slip angle command capability to improve manual control precision in approach and landing under crosswind and lateral wind shear conditions.

Abstract: An area navigation system capable of operating during an ILS approach to provide the pilot range and bearing with respect to the outer and middle markers for a front course approach, and with respect to the final approach fix and the end of the runway for a back course approach. The system operates by automatically connecting the # 2 NAV receiver to the RNAV during ILS operation while the ILS localizer converter is connected to the # 1 NAV receiver. At the same time the RNAV is disconnected from the left side indicator so this may be used for the localizer.

Abstract: The guidance system for a flying vehicle having at least one guidance channel for converting an error signal to a command signal for a control surface servo of the vehicle includes means for damping oscillations at the natural frequency of the vehicle. A damping means includes a notch filter in the guidance channel which serves to damp oscillations at the notch frequency. The notch frequency is controlled and conformed to the natural frequency of the vehicle, as the natural frequency of the vehicle varies with vehicle speed, by providing the notch filter with a signal related to vehicle speed. The notch filter is arranged to vary the notch frequency in accordance with the signal provided thereto.

Abstract: Guidance along the runway centerline when visibility conditions do not permit adequate visual cues for manual control are provided utilizing lateral acceleration and bank angle information. An aircraft type airborne vehicle can touchdown with a crab angle in the presence of a crosswind and the present system provides the proper command to decrab the aircraft and return the aircraft to the centerline.

Abstract: For use with a microwave landing system of the type including a ground based station for generating a relatively wide aircraft navigational beam and airborne equipment for deriving precision azimuth, elevation, and range data therefrom, airborne equipment utilizing the data to guide the craft along a multi-segment path so that each of the segments is asymptotically captured by the craft.