Abstract: A very high frequency omni-range (VOR) receiver for use in aircraft radio-navigation, which provides an indication of course deviation that is substantially immune to effects such as reflections in transmitted VOR signals, transients occurring in an aircraft's electrical system and propeller and/or rotor modulations of an incoming VOR signal and the like which are all unrelated to actual course deviation, is disclosed. The receiver phase synchronizes a signal from a 1.08 MHz crystal oscillator to a 30 Hz reference signal and a 30 Hz variable signal; both the reference and variable signals are received from a VOR ground station. As a result of the phase synchronization, the receiver produces timing pulses which are accurately phase synchronized to a synchronized reference pulse stream derived from the 30 Hz reference signal. Additionally, the receiver produces a synchronized variable pulse stream that is derived from the 30 Hz variable signal.

Abstract: A vertical speed indicator uses a substantially rigid hollow closed air chamber; a capillary tube having a reduced inside diameter connected to the chamber for routing atmospheric air from an aircraft static system at a reduced flow rate into the chamber; a differential pressure transducer having two inlet ports; a pneumatic conduit connecting the chamber and one of the ports of the transducer for exposing that port to internal chamber air pressure; a pneumatic conduit connected to the other port for exposing that port to atmospheric pressure occurring within the static system; and electronic processing circuitry connected to the transducer for providing an indication of the vertical speed of the aircraft.

Abstract: Apparatus for a digital averaging filter, particularly suited for use with an aeronautical navigation receiver, for reducing oscillatory deviation errors that appear in a course deviation voltage produced by the receiver and occur as the result of reflected incoming radio-navigation signals and/or interfering signals as described. In essence, this apparatus first amplifies, filters and repetitively samples the course deviation voltage to provide digital representations thereof. Each digital representation is then converted by a digital to pulse count converter into a series of pulses wherein the value of each digital representation is encoded into the number of pulses in the series. Thereafter, these pulses are totalized over a pre-defined interval. The resulting totalized count is then divided to produce an average value, which at the end of the pre-defined interval accurately reflects the average course deviation error.

Abstract: A very high frequency omni-range (VOR) receiver for use in aircraft radio-navigation, which provides an indication of course deviation that is substantially immune to effects such as reflections in transmitted VOR signals, transients occurring in an aircraft's electrical system and propeller and/or rotor modulations of an incoming VOR signal and the like which are all unrelated to actual course deviation, is disclosed. Specifically, in accordance with the invention, a stream of timing pulses is generated which are accurately phase-locked to a stream of pulses corresponding to a received reference signal transmitted from a desired VOR station. Both these streams are then used to produce an "OBS" signal which is phase shifted by an amount representative of a preselected radial emitted by that station.

Abstract: Apparatus and method for use in instrument landing system (ILS) localizer and/or glide-slope receivers for deriving course deviation information are described. Specifically, a detected incoming ILS (localizer or glide-slope) signal is first filtered in order to extract appropriate 90 and 150 Hz navigation tones therefrom. Thereafter, two streams of timing pulses are generated; the first stream is phase-locked to the 90 Hz navigation tone and the second stream is phase-locked to the 150 Hz navigation tone. The peak amplitude of the 90 Hz navigation tone is sampled in response to the occurrence of a particular timing pulse occurring in the first pulse stream and the peak amplitude of the 150 Hz navigation tone is sampled in response to the occurrence of a particular timing pulse occurring in the second pulse stream.