Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Aeronautical vehicle
Reexamination Certificate
2000-05-12
2001-11-27
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Aeronautical vehicle
C701S001000, C701S003000, C701S004000, C701S005000, C701S213000, C701S220000, C342S029000, C342S030000, C342S036000, C342S046000, C342S049000, C342S032000, C342S050000, C342S057000, C342S037000, C342S352000, C342S357490, C340S970000, C340S977000, C340S945000, C340S963000, C340S980000, C340S974000, C340S988000, C244S180000, C244S181000, C244S182000, C244S188000
Reexamination Certificate
active
06324448
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to methods, apparatus and computer program products for determining the vertical speed of an aircraft and, more particularly, to methods, apparatus and computer program products for determining the vertical speed of an aircraft for use in a ground proximity warning system.
BACKGROUND OF THE INVENTION
Within aviation, the vertical speed or vertical velocity of an aircraft is an important flight parameter and is utilized in a variety of different manners. For example, a traffic collision avoidance system (TCAS) utilizes the vertical speed of an aircraft in its determination of aircraft separation and the performance of other navigation maintenance management functions.
A measure of the vertical speed of an aircraft can be provided by one of several different types of avionics equipment conventionally carried by commercial aircraft. For example, an inertial navigation system (INS) or an initial reference system (IRS) can provide signals indicative of the vertical speed, as well as the acceleration, attitude, altitude, position, magnetic heading/track, true heading/track and ground speed of an aircraft. Alternatively, an air data computer (ADC) can provide signals indicative of vertical speed, as well as the altitude, the computed airspeed, the corrected altitude, the true airspeed and the static air temperature.
By way of example, one particularly significant avionics subsystem that utilizes the vertical speed of the aircraft, as well as a number of other flight parameters, is a ground proximity warning system. Ground proximity warning systems, also known as terrain awareness systems, analyze the flight parameters of the aircraft, including the vertical speed, and the terrain surrounding the aircraft. Based on this analysis, these warning systems provide alerts to the flight crew concerning possible inadvertent collisions of the aircraft with surrounding terrain or other obstacles, including instances in which the flight path of the aircraft would appear to bring the aircraft in short of the runway.
Ground proximity warning systems often have several modes in order to provide various types of alerts depending upon the flight conditions. For example, the enhanced ground proximity warning system provided by Honeywell, Inc. has six primary modes of operation, at least two of which are dependent upon the vertical speed of the aircraft. In this regard, Mode 1 is designed to provide alerts for an aircraft having an excessive descent rate, i.e., a negative vertical velocity with an excessively large magnitude, that is relatively close to the underlying terrain. Mode 2 provides an alert in instances in which an aircraft is closing with the terrain at an excessive rate, even in instances in which the aircraft is not descending. Mode 3 provides alerts in instances in which an aircraft loses significant altitude immediately after take off or during a missed approach. Mode 3 is activated and deactivated, however, based upon the vertical velocity of the aircraft. Mode 4 provides alerts for insufficient terrain clearance based upon the phase of flight and the speed of the aircraft. In this regard, Mode 4 provides alerts based upon different criteria depending upon whether the aircraft is in the take off phase of flight or in the cruise or approach phases of flight and further depending upon whether the gear is in a landing configuration. Mode 5 also provides two levels of alerts when the aircraft flight path descends below the glideslope beam on front course instrument landing system (ILS) approaches. Finally, Mode 6 provides alerts or call-outs for descent below predefined altitudes or the like during an approach, as well as alerts for excessive roll or bank angles.
In addition to the various modes of operation, the enhanced ground proximity warning system provided by Honeywell, Inc. defines an alert envelope and, more particularly, both a caution envelope and a warning envelope. The imaginary alert envelopes move with the aircraft and are constructed to extend forwardly of the aircraft and to define a region in which alerts will be generated if terrain or other obstacles enter by penetrating one of the alert envelopes. In this regard, U.S. Pat. No. 5,839,080 to Hans R. Muller et al. and assigned to AlliedSignal Inc. describes an advantageous ground proximity warning system that generates an alert envelope. The contents of U.S. Pat. No. 5,839,080 are hereby incorporated by reference in their entirety.
As described by U.S. Pat. No. 5,839,080, an alert envelope is defined by a number of parameters, including a look ahead distance (LAD), a base width (DOFF) and a terrain floor (&Dgr;H). In general terms, the look ahead distance defines the distance in advance to the aircraft that the alert envelope extends. Similarly, the base width is the lateral width of the alert envelope at a location proximate the aircraft. Further, the terrain floor typically defines a vertical distance below the aircraft that is utilized during the construction of the floor of the alert envelope. Oftentimes, the terrain floor slopes downwardly or upwardly depending upon the flight path angle of the aircraft which, in turn, is at least partially dependent upon the vertical speed of the aircraft. Accordingly, the construction of the alert envelope is partly dependent upon the vertical speed of the aircraft.
As described by U.S. Pat. No. 5,839,080, the ground proximity warning system can construct a pair of alert envelopes, namely, a caution envelope and a warning envelope, that are each partly dependent upon the vertical speed of the aircraft as described above. While each envelope has a similar shape as described above, the caution envelope typically extends further ahead of the aircraft than the warning envelope and is therefore generally larger than the warning envelope. Accordingly, the ground proximity warning system will generate cautionary alerts in instances in which the upcoming terrain or other obstacles penetrate the caution envelope, but not the warning envelope. Once the upcoming terrain or other obstacles penetrate the warning envelope, however, the ground proximity warning system will generate a more severe warning alert. As such, a pilot can discern the severity of the alert and the speed with which evasive maneuvers must be taken in order to avoid the upcoming terrain or other obstacles based upon the type of alert that is provided, i.e., a less severe cautionary alert or a more severe warning alert.
While ground proximity warning systems have substantially improved the situational awareness of flight crews of commercial aircraft by providing a variety of alerts of upcoming situations that merit the attention of the flight crews and by providing graphical displays of the upcoming terrain, obstacles and other notable features, ground proximity warning systems generally require a relatively robust set of input parameters, including the vertical speed of the aircraft as noted above. For example, conventional ground proximity warning systems require a signal indicative of the radio altitude from a radio altimeter, signals indicative of the altitude, the computed airspeed, the corrected altitude, the barometric altitude rate, i.e., the vertical speed, the true airspeed and the static air temperature from an Air Data Computer (ADC), signals indicative of the position, the magnetic track and the corrected altitude from a Flight Management System (FMS), signals indicative of the acceleration, attitude, altitude, vertical speed, position, magnetic heading/track, true heading/track and ground speed from an inertial reference system (IRS), an inertial navigation system (INS) and/or an attitude heading reference system (AHRS), signals indicative of the position, position quality, altitude, ground speed, ground track, date, time and status from a global navigation positioning system (GNPS) or a global positioning system (GPS) (hereinafter collectively referenced as a GPS), signals indicative of the glideslope deviation, a localizer deviation and the selecte
Cuchlinski Jr. William A.
Honeywell International Inc
Mancho Ronnie
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