Ryan International Corporation

Avidyne Corporation

William C Brodegard

Dean E Ryan

Paul A Ryan

A critical point on a runway indicates a point at which an aircraft may experience a runway overrun if landing beyond the critical point. A path projection is extended from the aircraft at a descent slope angle to determine whether the aircraft will land beyond the critical point at the current descent slope. Timely alerts may be provided by accounting for the time required to announce a distance value, and the distance traveled during the announcement.

Method and apparatus for predicting runway overrun

A proximity warning device for aircraft responds solely to transmissions from transponders. The host aircraft has a host transponder and a signal is generated therein and coupled to the device to indicate transmission of a host reply. Selective suppression is implemented based on presence of an SSR beam which is indicated by the signal. Suppression pulses have a fixed duration but randomly selected intervening durations. Data collection proceeds without regard for suppression or the presence of host replies. The shaping of data collection intervals free of interference from suppression provides for improved efficiency for later data decoding and processing. The signal is used to specially mark collected data generated by a host reply. The ability to discriminate between host and other replies allows completely new performance monitoring functions. In one case, the health of the receiver is deduced from the amplitude of host replies. In another case the effectiveness of suppression is noted by capturing host replies in the presence of a suppression pulse.

Aircraft traffic alert and collision avoidance device

A passive aircraft Traffic alert and Collision Avoidance Device (TCAD) is based on sensing and responding to transponder replies of other aircraft to SSR interrogations. In order to avoid masking other aircraft replies by the host transponder TCAD repeatedly and randomly suppresses the host transponder and simultaneoulsly listens for other aircraft replies. Suppression on each occasion is effective for an equal and predetermined duration which is much longer than a typical replay, in a preferred embodiment the suppression/listen duration is 725 .mu.s. In this embodiment the time between successive suppression/listen occasions is random between 725 .mu.s. and 5.025 ms. with an average value of about 2.9 ms. Digital signal processing is used to detect and discard garbled or overlapping replies. Each valid reply, exhibiting a minimum pulse amplitude, is decoded and correlated with a calibrated range parameter and given a time tag. Successive replies which match to within predetermined criteria in time and calibrated range are merged to track the positional relation between the host and other aircraft. The positional relation between other aircraft and the host are evaluated via a priority table in terms of relative altitude and range to locate that craft which poses the highest threat to the host. Parameters of such a craft are displayed. In the event a craft penetrates a shield of programmable size an audible alert is sounded. TCAD provides for shields for each of a plurality of flight regimes, such as terminal, standard and enroute.

A passive aircraft Traffic alert and Collision Avoidance device (TCAD) is based on sensing and responding to transponder replies of other aircraft to SSR interrogations. In order to avoid masking other aircraft replies by the host transponder TCAD repeatedly and randomly suppresses the host transponder and simultaneously listens for other aircraft replies. Suppression on each occasion is effective for an equal and predetermined duration which is much longer than a typical reply, in a preferred embodiment the suppression/listen duration is 725 .mu.s. In this embodiment the time between successive suppression/listen occasions is random between 725 .mu.s. and 5.025 ms. with an average value of about 2.9 ms. Digital signal processing is used to detect and discard garbled or overlapping replies. Each valid reply, exhibiting a minimum pulse amplitude, is decoded and correlated with a calibrated range parameter and given a time tag. Successive replies which match to within predetermined criteria in time and calibrated range are merged to track the positional relation between the host and other aircraft. The positional relation between other aircraft and the host are evaluated via a priority table in terms of relative altitude and range to locate that craft which poses the highest threat to the host. Parameters of such a craft are displayed. In the event a craft penetrates a shield of programmable size an audible alert is sounded. TCAD provides for shields for each of a plurality of flight regimes, such as terminal, standard and enroute. Selection among shields is via a single pushbutton. TCAD allows the pilot to program each of the different shield sizes. Peripheral functions such as altitude deviation alert, density altitude and barometric pressure correction for altitude reporting are also provided.

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Columbus, OH, United States of America

William C Brodegard