Patent Description:
The present invention generally relates to enhanced ground proximity warning systems (EGPWSs), and more particularly relates to an EGPWS that can selectively operate in either a helicopter mode or a fixed-wing mode.

The aircraft envisioned for use as urban air mobility (UAM) aircraft are typically configured as vertical take-off and landing (VTOL) aircraft. These aircraft, as well as VTOL aircraft presently used in other domains, such as military domains, can selectively operate in both a helicopter mode and a fixed-wing mode. More specifically, VTOL aircraft can take-off and land like a helicopter (i.e., helicopter mode) and cruise like a fixed-wing aircraft (i.e., fixed-wing mode). Therefore, some VTOL aircraft flight operations may involve flying characteristics of both a helicopter and fixed-wing aircraft in one flight.

One of the avionic systems that is (or will be) installed in UAM aircraft is the enhanced ground proximity warning system (EGPWS). As is generally known, the EGPWS uses various aircraft inputs and an internal database to predict and warn flight crews of potential conflicts with obstacles or terrain, thereby significantly reducing the risk of controlled flight into terrain. As is also generally known, an EGPWS disposed on a helicopter is configured slightly differently than an EGPWS disposed on a fixed-wing aircraft. In particular, the EGPWS in a helicopter has warning thresholds set to allow the aircraft to fly at lower altitudes and in more congested areas, and to land outside of an airport environment, without triggering an alert, whereas the EGPWS in a fixed-wing aircraft has alert thresholds associated with relatively higher altitude, lower congested flight operations.

Hence, there is a need for a system and method that allows for an EGPWS to function as a helicopter EGPWS when an aircraft is operating as in the helicopter mode, and as a fixed-wing EGPWS when the aircraft is operating in the fixed-wing mode. The present disclosure addresses at least this need.

In one embodiment, a system for an aircraft that is configured to selectively operate in both a helicopter mode and a fixed-wing mode includes an enhanced ground proximity warning system (EGPWS), at least one sensor, and a processor. The EGPWS is configured, in response to a command, to selectively operate as a helicopter EGPWS or as a fixed-wing EGPWS. The at least one sensor is configured to sense at least one aircraft flight parameter and to supply sensor data representative of the at least one aircraft flight parameter. The processor is in operable communication with the at least one sensor and is configured to: process the sensor data to determine when the aircraft is operating in the helicopter mode and when the aircraft is operating in the fixed-wing mode; command the EGPWS to operate as the helicopter EGPWS when the aircraft is operating in the helicopter mode; and command the EGPWS to operate as the fixed-wing EGPWS when the aircraft is operating in the fixed-wing mode.

In another embodiment, a method for controlling operations of an enhanced ground proximity warning system (EGPWS) disposed within an aircraft that is configured to selectively operate in both a helicopter mode and a fixed-wing mode includes processing, in a processor, one or more aircraft flight parameters to determine when the aircraft is operating in the helicopter mode and when the aircraft is operating in the fixed-wing mode. The EGPWS is commanded, via the processor, to operate as a helicopter EGPWS when the aircraft is operating in the helicopter mode, and is commanded, via the processor, to operate as a fixed-wing EGPWS when the aircraft is operating in the fixed-wing mode.

In yet another embodiment, a system for an aircraft that is configured to selectively operate in both a helicopter mode and a fixed-wing mode includes an enhanced ground proximity warning system (EGPWS), a flight management system (FMS), and a processor. The EGPWS is configured, in response to a command, to selectively operate as a helicopter EGPWS or as a fixed-wing EGPWS. The FMS is configured to at least supply a signal representative of a phase of flight of the aircraft. The processor is coupled to receive the signal from the FMS and is configured, upon receipt thereof, to: command the EGPWS to operate as the helicopter EGPWS when the signal indicates the phase of flight of the aircraft is either a takeoff mode or an approach mode, and command the EGPWS to operate as the fixed-wing EGPWS when the phase of flight of the aircraft is neither the takeoff mode nor the approach mode.

Furthermore, other desirable features and characteristics of the system and method will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the preceding background.

Referring to <FIG>, a functional block diagram of one embodiment of an aircraft system <NUM> is depicted. The system <NUM> includes an enhanced ground proximity warning system (EGPWS) <NUM>, at least one sensor <NUM>, and a processor <NUM>. The system <NUM>, at least in the depicted embodiment, is disposed at least partially within an aircraft <NUM>. More specifically, it is disposed within or on the fuselage <NUM> of a vertical take-off and landing (VTOL) aircraft <NUM>, which is configured to selectively operate in either a helicopter mode or a fixed-wing mode.

The EGPWS <NUM> is disposed within the fuselage <NUM> and is configured, in response to a command, to selectively operate as a helicopter EGPWS or as a fixed-wing EGPWS. As noted above, when operating as a helicopter EGPWS, the warning thresholds are set to allow the aircraft <NUM> to fly at lower altitudes and in more congested areas without triggering a warning, whereas a fixed-wing EGPWS has warning thresholds associated with relatively higher altitude, lower congested flight operations.

The at least one sensor <NUM> is disposed within or on the fuselage <NUM>. The at least one sensor <NUM> is configured to sense at least one aircraft flight parameter and to supply sensor data representative of the at least one aircraft flight parameter. The particular flight parameter(s) that is(are) sensed may vary, and thus the particular type of sensor(s) <NUM> may also vary. As will be discussed in more detail below, in one embodiment the aircraft flight parameter is a thrust vector <NUM>, and in another embodiment the aircraft flight parameter is aircraft speed, in yet another embodiment the aircraft flight parameter may be a phase of flight.

Regardless of the specific type of sensor(s) and specific aircraft flight parameter(s), the processor <NUM> is in operable communication with the at least one sensor <NUM> and is configured to process the sensor data to determine when the aircraft <NUM> is operating in the helicopter mode and when the aircraft <NUM> is operating in the fixed-wing mode. When the processor <NUM> determines that the aircraft <NUM> is operating in the helicopter mode, the processor <NUM> commands the EGPWS <NUM> to operate as a helicopter EGPWS. Conversely, when processor <NUM> determines that the aircraft <NUM> is operating in the fixed-wing mode, the processor <NUM> commands the EGPWS <NUM> to operate as a fixed-wing EGPWS.

It will be appreciated that although the processor <NUM> is depicted separately from the EGPWS <NUM>, this is done merely for clarity and ease of illustration and description. Indeed, in some embodiments the processor <NUM> may form part of the EGPWS <NUM>. Depending on the embodiment, the processor <NUM> may be implemented or realized with a general purpose processor, a controller, a microprocessor, a microcontroller, a content addressable memory, a digital signal processor, an application specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, processing core, discrete hardware components, or any combination thereof, designed to perform the functions described herein. In practice, the processor <NUM> includes processing logic that may be configured to carry out the functions, techniques, and processing tasks associated with the operation of the system <NUM> described in greater detail below. Furthermore, the steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in firmware, in a software module executed by the processor <NUM>, or in any practical combination thereof. In accordance with one or more embodiments, the processor <NUM> includes or otherwise accesses a data storage element, such as a memory (e.g., RAM memory, ROM memory, flash memory, registers, a hard disk, or the like) or another suitable non-transitory short or long term storage media capable of storing computer-executable programming instructions or other data for execution that, when read and executed by the processor <NUM>, cause the processor <NUM> to execute and perform one or more of the processes, tasks, operations, and/or functions described herein.

As noted above, the one or more aircraft flight parameters may be, in some embodiments, a thrust vector <NUM>. In such embodiments, the processor <NUM> is configured to determine that the aircraft <NUM> is operating in the fixed-wing mode when the thrust vector <NUM> is less than a predetermined angle (α) relative to a reference line <NUM>, and is configured to determine that the aircraft <NUM> is operating in the helicopter mode when the thrust vector <NUM> is greater than the predetermined angle (α) relative to the reference line <NUM>. The predetermined angle (α) may vary depending on the particular type of VTOL aircraft <NUM> and/or the selected location of the reference line <NUM>. In any case, however, it is selected to provide a clear demarcation between operation in the helicopter mode and the fixed-wing mode.

It will additionally be appreciated that the technique used to sense and determine the thrust vector <NUM> may vary depending, for example, on the configuration of the VTOL aircraft <NUM>. For example, some VTOL aircraft <NUM>, such as the one depicted in <FIG> and <FIG>, include a plurality of propulsion sources <NUM> (only one visible) that are rotatable, relative to the reference line <NUM>, to a plurality of rotational positions. In such embodiments, the processor <NUM> is configured to determine the thrust vector <NUM> based on the rotational position of each of the propulsion sources <NUM>, and is further configured to compare the determined thrust vector <NUM> to the predetermined angle (α).

To implement this functionality, the at least one sensor <NUM> may be implemented using a plurality of position sensors <NUM>. Each position sensor <NUM>, which may be implemented using any one of numerous types of position sensors, is configured to sense the rotational position of a different one of the plurality of propulsion sources <NUM> and to supply a rotational position signal representative of the rotational position to the processor <NUM>. The processor <NUM> receives the rotational position signal from each position sensor <NUM> and processes the position signals to determine the rotational position of each of the propulsion sources <NUM>.

In other embodiments, such as the one depicted in <FIG>, the VTOL aircraft <NUM> includes at least one fixed vertical propulsion source <NUM> and at least one fixed horizontal propulsion source <NUM>. The at least one vertical propulsion source <NUM> is configured to generate a vertical thrust component, and the at least one horizontal propulsion source <NUM> is configured to generate a horizontal thrust component, and the processor is configured to determine the thrust vector <NUM> based on a vector sum of the vertical thrust component and the horizontal thrust component. As used herein, the term "fixed" means that the propulsion sources <NUM>, <NUM>, unlike those in the embodiment depicted in <FIG> and <FIG>, are not rotatable to various positions relative to the reference line <NUM>. Rather, the propulsion sources <NUM>, <NUM> remain in a fixed position.

To implement this functionality, the at least one sensor <NUM> may be implemented using at least one first sensor <NUM>-<NUM> and at least one second sensor <NUM>-<NUM>. The at least one first sensor <NUM>-<NUM> is coupled to the at least one vertical propulsion source <NUM> and is configured to sense at least one parameter representative of the vertical thrust component and to supply a first sensor signal representative thereof to the processor <NUM>. Similarly, the at least one second sensor <NUM>-<NUM> is coupled to the at least one horizontal propulsion source <NUM> and is configured to sense at least one parameter representative of the horizontal thrust component and to supply a second sensor signal representative thereof to the processor <NUM>. The processor <NUM> receives and processes the first and second sensor signals and is configured to determine the vertical thrust component from the first sensor signal, and the horizontal thrust component from the second sensor signal.

Before proceeding further, it should be noted that the at least one parameter representative of the vertical and horizontal thrust, and thus the at least one first and second sensors <NUM>-<NUM>, <NUM>-<NUM>, may vary. It should be further noted that the at least one parameter may also vary depending on the type of propulsion sources used. For example, in some embodiments, in which the propulsion sources <NUM>, <NUM> are non-jet engines, the at least one parameter may be engine torque and/or a predetermined ratio between engine torque on the propulsion sources. In such embodiments, the at least one first and second sensors <NUM>-<NUM>, <NUM>-<NUM> are engine torque sensors. In other embodiments, in which the propulsion sources <NUM>, <NUM> are jet engines, the at least one parameter may be engine pressure ratio (EPR), which is the ratio of the turbine exhaust pressure divided by the pressure at the fan or inlet. In such embodiments, the at least one first and second sensors <NUM>-<NUM>, <NUM>-<NUM> are each implemented using two separate pressure sensors for each propulsion source <NUM>, <NUM>.

In other embodiments, as was also previously noted, the one or more aircraft flight parameters may be airspeed. In such embodiments, the processor <NUM> is configured to determine that the aircraft <NUM> is operating in the fixed-wing mode when the airspeed is greater than a predetermined speed magnitude, and to determine that the aircraft <NUM> is operating in the helicopter mode when the airspeed is less than the predetermined speed magnitude. The predetermined speed may vary depending, for example, on the particular type of VTOL aircraft <NUM>. As with the previously described embodiments, however, it is selected to provide a clear demarcation between operation in the helicopter mode and the fixed-wing mode.

To implement this functionality, the at least one sensor <NUM> may be implemented using at least one airspeed sensor. The at least one airspeed sensor is configured to sense the airspeed and to supply an airspeed signal representative thereof to the processor <NUM>. The processor <NUM> receives and processes the airspeed signal to determine the airspeed, and then compares the determined airspeed to the predetermined speed magnitude.

Having described the overall functionality of the system <NUM> generally, a method that is implemented in the system <NUM> will now be described. The method <NUM>, which is depicted in flowchart form in <FIG>, represents various embodiments of a method for selectively operating the EGPWS <NUM> in as a helicopter EPGWS or a fixed-wing EGPWS. For illustrative purposes, the following description of method <NUM> may refer to elements mentioned above in connection with <FIG>. In practice, portions of method <NUM> may be performed by different components of the described system <NUM>. It should be appreciated that method <NUM> may include any number of additional or alternative tasks, the tasks shown in <FIG> need not be performed in the illustrated order, and method <NUM> may be incorporated into a more comprehensive procedure or method having additional functionality not described in detail herein.

The method <NUM> starts when the system <NUM> is initialized. The processor <NUM> processes the one or more aircraft flight parameters (<NUM>) and determines whether the aircraft is operating in the helicopter mode or in the fixed-wing mode (<NUM>). When the aircraft <NUM> is operating in the helicopter mode, the processor <NUM> commands the EGPWS <NUM> to operate as a helicopter EGPWS (<NUM>). When the aircraft <NUM> is operating in the fixed-wing mode, the processor <NUM> commands the EGPWS <NUM> to operate as a fixed-wing EGPWS (<NUM>).

As was previously noted, in other embodiments the aircraft flight parameter may be a phase of flight of the aircraft <NUM>. In such embodiments, as depicted in <FIG>, the system <NUM> may use a flight management system (FMS) <NUM> to supply the aircraft flight parameter - that is, the phase of flight of the aircraft <NUM> - to the processor <NUM>. More specifically, with this embodiment, the FMS <NUM> will supply a signal to the processor <NUM> indicating the phase of flight of the aircraft <NUM>. The processor <NUM>, in response to this signal, will command the EGPWS <NUM> to operate as a helicopter EGPWS when the signal indicates that the aircraft <NUM> is operating in the takeoff mode or the approach mode, indicating that it is in the helicopter mode. Otherwise, when not operating in either the takeoff mode or the approach mode, the aircraft <NUM> will be considered to be operating in the fixed-wing mode and the processor <NUM> will command the EGPWS <NUM> to operate as a fixed-wing EGPWS.

The system and method disclosed herein allows an EGPWS to function as a helicopter EGPWS when an aircraft is operating in a helicopter mode, and as a fixed-wing EGPWS when the aircraft is operating in a fixed-wing mode.

The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein.

Techniques and technologies may be described herein in terms of functional and/or logical block components, and with reference to symbolic representations of operations, processing tasks, and functions that may be performed by various computing components or devices. Such operations, tasks, and functions are sometimes referred to as being computer-executed, computerized, software-implemented, or computer-implemented. In practice, one or more processor devices can carry out the described operations, tasks, and functions by manipulating electrical signals representing data bits at memory locations in the system memory, as well as other processing of signals. The memory locations where data bits are maintained are physical locations that have particular electrical, magnetic, optical, or organic properties corresponding to the data bits. It should be appreciated that the various block components shown in the figures may be realized by any number of hardware, software, and/or firmware components configured to perform the specified functions.

When implemented in software or firmware, various elements of the systems described herein are essentially the code segments or instructions that perform the various tasks. The program or code segments can be stored in a processor-readable medium or transmitted by a computer data signal embodied in a carrier wave over a transmission medium or communication path. The "computer-readable medium", "processor-readable medium", or "machine-readable medium" may include any medium that can store or transfer information. Examples of the processor-readable medium include an electronic circuit, a semiconductor memory device, a ROM, a flash memory, an erasable ROM (EROM), a floppy diskette, a CD-ROM, an optical disk, a hard disk, a fiber optic medium, a radio frequency (RF) link, or the like. The computer data signal may include any signal that can propagate over a transmission medium such as electronic network channels, optical fibers, air, electromagnetic paths, or RF links. The code segments may be downloaded via computer networks such as the Internet, an intranet, a LAN, or the like.

Some of the functional units described in this specification have been referred to as "modules" in order to more particularly emphasize their implementation independence. For example, functionality referred to herein as a module may be implemented wholly, or partially, as a hardware circuit comprising custom VLSI circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices, or the like. Modules may also be implemented in software for execution by various types of processors. An identified module of executable code may, for instance, comprise one or more physical or logical modules of computer instructions that may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together, but may comprise disparate instructions stored in different locations that, when joined logically together, comprise the module and achieve the stated purpose for the module. Indeed, a module of executable code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network.

As used herein, the term "axial" refers to a direction that is generally parallel to or coincident with an axis of rotation, axis of symmetry, or centerline of a component or components. For example, in a cylinder or disc with a centerline and generally circular ends or opposing faces, the "axial" direction may refer to the direction that generally extends in parallel to the centerline between the opposite ends or faces. In certain instances, the term "axial" may be utilized with respect to components that are not cylindrical (or otherwise radially symmetric). For example, the "axial" direction for a rectangular housing containing a rotating shaft may be viewed as a direction that is generally parallel to or coincident with the rotational axis of the shaft. Furthermore, the term "radially" as used herein may refer to a direction or a relationship of components with respect to a line extending outward from a shared centerline, axis, or similar reference, for example in a plane of a cylinder or disc that is perpendicular to the centerline or axis. In certain instances, components may be viewed as "radially" aligned even though one or both of the components may not be cylindrical (or otherwise radially symmetric). Furthermore, the terms "axial" and "radial" (and any derivatives) may encompass directional relationships that are other than precisely aligned with (e.g., oblique to) the true axial and radial dimensions, provided the relationship is predominantly in the respective nominal axial or radial direction. As used herein, the term "substantially" denotes within <NUM>% to account for manufacturing tolerances. Also, as used herein, the term "about" denotes within <NUM>% to account for manufacturing tolerances.

Claim 1:
A system (<NUM>) for an aircraft (<NUM>) that is configured to selectively operate in both a helicopter mode and a fixed-wing mode, the system comprising:
an enhanced ground proximity warning system, EGPWS, (<NUM>) configured, in response to a command, to selectively operate as a helicopter EGPWS or as a fixed-wing EGPWS;
at least one sensor (<NUM>) configured to sense at least one aircraft flight parameter and to supply sensor data representative of the at least one aircraft flight parameter; and
a processor (<NUM>) in operable communication with the at least one sensor and configured to:
process the sensor data to determine when the aircraft is operating in the helicopter mode and when the aircraft is operating in the fixed-wing mode;
command the EGPWS to operate as the helicopter EGPWS when the aircraft is operating in the helicopter mode; and
command the EGPWS to operate as the fixed-wing EGPWS when the aircraft is operating in the fixed-wing mode.