Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Aeronautical vehicle
Reexamination Certificate
2000-03-24
2004-08-31
Nguyen, Tan Q. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Aeronautical vehicle
C701S206000, C340S970000
Reexamination Certificate
active
06785594
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to ground proximity warning systems and methods and, more particularly, to ground proximity warning systems and methods having a reduced set of input parameters in order, for example, to enhance the situational awareness of the pilots of general aviation aircraft in a cost effective manner.
BACKGROUND OF THE INVENTION
An important advancement in aircraft flight safety has been the development of ground proximity warning systems, also known as terrain awareness systems. These warning systems analyze the flight parameters of the aircraft 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 AlliedSignal Inc. has six primary modes of operation. Mode
1
is designed to provide alerts for an aircraft having an excessive descent rate 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
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 AlliedSignal 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 terrain floor typically defines a vertical distance below the aircraft which is utilized during the construction of the floor of the alert envelope. Further, the base width is the lateral width of the alert envelope at a location proximate 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. 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.
In addition to the various modes of operation and the alert envelopes described above, ground proximity warning systems can also provide other types of alerts. For example, the enhanced ground proximity warning system provided by AlliedSignal Inc. also provides a terrain clearance floor (TCF) alert. In particular, the enhanced ground proximity warning system creates an increasing terrain clearance envelope around an intended runway and alerts are provided if the flight path of the aircraft penetrates the terrain clearance floor, thereby providing alerts if the flight path of the aircraft indicates that the aircraft may land short of the runway. See, for example, U.S. patent application Ser. No. 09/496,296, entitled “Apparatus, Method, and Computer Program Product for Generating Terrain Clearance Floor Envelopes about a Selected Runway” filed Feb. 1, 2000 and U.S. patent application Ser. No. 09/454,924, entitled “Methods, Apparatus and Computer Program Products for Automated Runway Selection” filed Dec. 3, 1999 (hereinafter the '924 application) which describe the generation of a terrain clearance floor and the selection of the runway about which the terrain clearance floor is constructed, respectively. The contents of both of these applications are herein incorporated by reference in their entirety.
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. 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 altitude rate, 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) 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 (GNSS) or a global positioning system (GPS) (hereinafter collectively referenced as a GPS), signals indicative of the glideslope deviation, a localizer deviation and the selected runway coordinates from an instrument landing system (ILS) and/or a microwave landing system (MLS) as well as other signals from other avionic subsystems. Therefore, for a conventional ground proximity warning system to be fully functional, the aircraft must not only carry the ground proximity warning system, but must also have a number of other subsystems, such as a radio altimeter, an ADC, an FMS, an IRS or an AHRS, a GPS and an ILS or a MLS. As will be apparent, each of these subsystems is quite expensive. However, most large commercial aircraft are mandated to have most, if not all, of the
Bateman C. Don
Johnson Steven C.
Honeywell Int'l Inc.
Honeywell International , Inc.
Nguyen Tan Q.
Tran Dalena
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