Patent Description:
Therefore, a more robust air data probe capable of measuring aircraft speed and angle of attack is needed. There is also a need for a simplified air data architecture that will reduce total ownership costs of the system.

<CIT> discloses an air pressure probe comprising a head part with intake holes located thereon. <CIT> discloses an air data sensor that determines a body's angle of attack, static air pressure, total air pressure, Mach number, static air temperature and true air speed in one device using pressure and temperature readings. <CIT> discloses a dynamic fluid flow sensing system that measures relative fluid velocity with respect to a reference member. The system includes a sensor housing supported from the reference member such that the sensor housing is exposed to fluid flowing past the reference member.

[<NUM>] The present invention is defined by the independent claims, to which reference should now be made.

Understanding that the drawings depict only exemplary embodiments and are not therefore to be considered limiting in scope, the exemplary embodiments will be described with additional specificity and detail through the use of the accompanying drawings, in which:.

In the following detailed description, embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that other embodiments may be utilized without departing from the scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense.

A multi-function air data probe for detecting airflow angle, static pressure, and total pressure, is described herein.

The air data probe generally includes a probe stem and a probe head coupled at one end of the probe stem, with the probe stem having a smaller diameter than the probe head. A plurality of multi-hole ports are located in the probe head. A base flange can be coupled to the probe stem at an opposite end, with the base flange having one or more static pressure ports. The air data probe is operative to make measurements used to determine total pressure, static pressure, and angle of attack values.

The probe stem and probe head can each have a substantially cylindrical shape. The probe stem and the probe head can optionally each include flow stability features on their outer surfaces. In some embodiments, the air data probe can also include a digital component and software algorithm that provides a self-aware health assessment and management capability for the probe.

The air data probe has the following technical benefits. The shape of the probe head enables precise fabrication, which leads to high quality probe calibration and pressure measurement. The shape of the probe head does not have any sharp edges, making it robust against handling, erosion, and hail impact damage. The probe head design is easily heated to protect against various icing threats (e.g., supercooled water droplets, ice crystals, rain). As the probe head is larger than the probe stem, this minimizes the influence of span-wise flow on the pressure measurement.

The multi-hole ports in the probe head have the benefit of reducing the influence of imperfections in each of the separate manifold pressure measurements. In addition, the multi-hole ports are robust against plugging from dirt, hail, icing, bugs, etc. The flow stability features on the probe head and stem when used provide the benefit of minimizing pressure fluctuations caused by wake vortex shedding. In one embodiment, the flow stability features are matching fins on left and right hand sides of a principle structure of the air data probe, with the fins having a substantially triangular cross section profile.

The air data probe has a robust design, with round parts, simple radial holes, no sharp edges around the holes, and simple routing for pressure tubes. The air data probe also allows for a simple heater layout configuration, using either a cable or film, and has an un-handed design.

The air data probe is designed for accurate measurement. For example, the multiple holes for each pressure sensor minimizes sensitivity to fabrication tolerances. In addition, the critical pressure sensing surface is axisymmetric. When the air data probe is mounted on a vehicle, the probe head is positioned outside of a boundary layer and peak ice concentration zones.

The air data probe is capable of making measurements that can be used to determine (ambient) total pressure (PTamb), (ambient) static pressure (PSamb) and angle of attack (AOA) values. The air data probe is configured to provide highly accurate static pressure (PS) measurements and total pressure (PT) measurements that are insensitive to AOA up to about ± <NUM>°. The air data probe is also configured to provide a highly accurate AOA measurement for an AOA up to about ± <NUM>°.

Further, the pressure measurement distribution of pressure (psi) modules in the air data probe can be compared with calibration curves to evaluate individual measurement degradation during operation.

When implemented on a vehicle such as an aircraft, the air data probe is configured to provide measurement of the aircraft AOA, static pressure, and total pressure. This enables calculation of aircraft speed, AOA, and altitude, for flight control management.

The air data probe provides a design that is simple to manufacture and for low cost, versus a traditional L-shaped or spherical head/nose designs. A cylindrical design of the air data probe also yields higher pressure, altitude, speed, and AOA accuracy, combined with the ability to self-diagnose individual degradation without losing functionality. Combined with onboard electronics, the air data probe can enable real-time monitoring of aircraft flight profile changes to enhance aircraft safety.

In addition, the air data probe can be implemented in a digital line replaceable unit (LRU) for an aircraft. The data generated by the air data probe can reside in onboard air data computers, or can be live-streamed to remote servers.

Further details of various embodiments are described hereafter with reference to the drawings.

<FIG> and <FIG> illustrate isometric views of a multi-function air data probe <NUM>, according to one example embodiment. The air data probe <NUM> generally includes a probe stem <NUM>, a probe head <NUM> coupled to probe stem <NUM> at one end, and a base flange <NUM> coupled to probe stem <NUM> at an opposite end. In one implementation, probe stem <NUM> has a substantially cylindrical shape with a first cross-sectional diameter, and probe head <NUM> has a substantially cylindrical shape with a second cross-sectional diameter that is larger than the first cross-sectional diameter of probe stem <NUM>.

In one embodiment, the cross-sectional diameter of probe head <NUM> can be at least about <NUM> percent larger than the cross-sectional diameter of probe stem <NUM>. In other embodiments, the cross-sectional diameter of probe head <NUM> can be about <NUM> to about <NUM> percent larger than the cross-sectional diameter of probe stem <NUM>. In addition, while air data probe <NUM> is shown to have an abrupt transition between probe stem <NUM> and probe head <NUM>, in other embodiments, the transition between the probe stem and probe head can be more gradual such as by using a tapered transition section.

The probe stem <NUM> has an outer surface <NUM> that extends between a first end <NUM> and an opposite second end <NUM>. Optionally, a set of flow stability structures <NUM> can protrude from and extend along outer surface <NUM> of probe stem <NUM>, as shown in <FIG>. The flow stability structures <NUM> encourage smooth air flow off a trailing edge of the structures to avoid vortex shedding. In one embodiment, flow stability structures <NUM> can have a substantially triangular shape.

The probe stem <NUM> can have a hollow structure, or a solid interior except for passageways, to provide for static pressure communication to base flange <NUM>.

The probe head <NUM> has an outer surface <NUM> that extends between a proximal end <NUM> and a distal end <NUM>. The proximal end <NUM> of probe head <NUM> is coupled to first end <NUM> of probe stem <NUM>. The outer surface <NUM> has an array of sensor holes <NUM> located along a portion thereof, as shown in <FIG>. The sensor holes <NUM> are configured to align with a plurality of multi-hole ports in probe head <NUM> (described further hereafter).

The probe head <NUM> can optionally have a set of flow stability structures <NUM> that protrude from and extend along outer surface <NUM>. The flow stability structures <NUM> generally align with flow stability structures <NUM> when present on probe stem <NUM>. The flow stability structures <NUM> encourage smooth air flow off a trailing edge of the structures to avoid vortex shedding. In one embodiment, flow stability structures <NUM> on probe head <NUM> can have a substantially triangular shape.

The probe head <NUM> can have a hollow structure, or a solid interior except for passageways, to provide for static pressure communication to probe stem <NUM> and base flange <NUM>. An optional drain hole <NUM> can be located in distal end <NUM> of probe head <NUM>. One or more static pressure ports (not shown) can be located in base flange <NUM>.

<FIG> is an enlarged isometric view of one end of air data probe <NUM>, showing further details of probe head <NUM> coupled to probe stem <NUM>. In this example embodiment, the array of sensor holes <NUM> includes a first sensor hole row <NUM>-<NUM>, a second sensor hole row <NUM>-<NUM>, a third sensor hole row <NUM>-<NUM>, a fourth sensor hole row <NUM>-<NUM>, and a fifth sensor hole row <NUM>-<NUM>. Each of the five sensor hole rows <NUM>-<NUM> to <NUM>-<NUM> include multiple sensor holes <NUM>. Although each sensor hole row is shown to have six holes, it should be understood that in other embodiments, more or less holes can be used in each row. <FIG> also shows a bar graph <NUM>, which depicts the (surface static pressure) / (free stream total pressure) (z_PS_PT_far) from a modeling simulation corresponding to air data probe <NUM>.

<FIG> are isometric interior views of probe head <NUM>. As depicted, a plurality of multi-hole ports <NUM> are located in probe head <NUM>, and are configured to extend into an through the probe stem. The multi-hole ports <NUM> include a first multi-hole port <NUM>-<NUM>, a second multi-hole port <NUM>-<NUM>, a third multi-hole port <NUM>-<NUM>, a fourth multi-hole port <NUM>-<NUM>, and a fifth multi-hole port <NUM>-<NUM>. Each of the multi-hole ports <NUM>-<NUM> to <NUM>-<NUM> include respective sensor manifold tubes <NUM>-<NUM> to <NUM>-<NUM>, which respectively communicate with sensor hole rows <NUM>-<NUM> to <NUM>-<NUM> (<FIG>) through multiple sets of port tubes <NUM>-<NUM> to <NUM>-<NUM>.

In one example, each of multi-hole ports <NUM>-<NUM> to <NUM>-<NUM> are connected to respective pressure transducers in pressure modules located in an air data sensor housing. The multi-hole ports <NUM>-<NUM> to <NUM>-<NUM> advantageously reduce the influence of imperfections in each of the five separate manifold pressure measurements.

As shown in <FIG>, a drain port <NUM> is communicatively coupled to sensor manifold tubes <NUM>-<NUM> to <NUM>-<NUM>. The drain port <NUM> communicates with drain hole <NUM> (<FIG> and <FIG>), to provide an outlet for excess air from manifold tubes <NUM>-<NUM> to <NUM>-<NUM>.

Although five multi-hole ports are shown in the embodiment of <FIG>, it should be understood that in other embodiments, more or less of such multi-hole ports can be used in an air data probe as needed, to achieve a desired performance for the probe.

<FIG> is a schematic illustration showing an exemplary vehicle mounting location for air data probe <NUM>. For example, air data probe <NUM> can be mounted on an aircraft <NUM> in a nose section <NUM>. <FIG> also shows a bar graph <NUM>, which depicts the (surface static pressure) / (free stream total pressure) (z_PS_PT_far) from a modeling simulation corresponding to air data probe <NUM> mounted on aircraft <NUM>.

The air data probe <NUM> is designed to meet PS, PT, and AOA requirements for a range of AOA of up to about ± <NUM>°. The PT is calculated directly from static pressures measured in the probe head. This is accomplished by curve fitting the results and calculating the maximum value. The AOA is also calculated directly from the static pressure measurements in the probe head using calibration test results. The rows of sensor holes in the probe head, combined with static pressure ports in the probe base flange and/or aircraft fuselage static ports, enable the meeting of static pressure measurement accuracy requirements for aircraft.

The air data probe <NUM> can measure static pressure values in two different ways: from the pressure values captured through sensor holes <NUM> in the probe head, as well as from the pressure values captured through independent static pressure ports in base flange <NUM>. It should be noted that the static pressure values measured in the probe head are not ambient static values. However, the ambient static, total, and AOA values can be extracted from the measurements taken at the different multi-hole sensor ports in the probe head using the approach described herein.

<FIG> illustrate various views of a multi-function air data sensor <NUM>, according to an exemplary embodiment. The air data sensor <NUM> includes an air data probe <NUM> that is configured to protrude into an airflow to collect air data, a base plate <NUM> for attaching air data probe <NUM> (e.g., to a fuselage of an aircraft), and a housing <NUM> coupled to base plate <NUM> at a first end of housing <NUM>. The housing <NUM> contains electronics (not shown) for interpreting the air data collected from air data probe <NUM>. For example, housing <NUM> can contain at least one processor and an associated memory component.

As shown in <FIG> and <FIG>, a pair of input/output couplers <NUM>, <NUM> are located at an opposite second end of housing <NUM>. The input/output couplers <NUM>, <NUM> are configured to provide for electrical connections with the electronics in housing <NUM>.

The air data probe <NUM> can have a similar structure as air data probe <NUM> described previously. As such, air data probe <NUM> generally includes a probe stem <NUM>, a probe head <NUM> coupled to probe stem <NUM> at one end, and a base flange <NUM> coupled to probe stem <NUM> at an opposite end. The base flange <NUM> is coupled to base plate <NUM> such as through a bolted ring structure <NUM>. The air data probe <NUM> is positioned at a first location that is offset from a center of base plate <NUM>. A set of multiple static pressure ports <NUM> are positioned at a second location on base plate <NUM>, with the second location also being offset from the center of base plate <NUM>.

The air data probe <NUM> and static pressure ports <NUM> are operative to make measurements used by the processor to determine angle of attack, total pressure, and static pressure values. In some embodiments, air data sensor <NUM> can be implemented in a digital line replaceable unit (LRU) for a vehicle such as an aircraft. For example, air data sensor <NUM> can be mounted in an aircraft nose section as part of a digital LRU, in one implementation.

In some implementations, the multi-function air data probe can incorporate a digital component and software algorithm method that provides a self-aware health assessment and management capability for the air data probe.

<FIG> is a flow diagram of a method <NUM> for providing health management and assessment for a multi-function air data probe, according to one implementation. The method <NUM> initially includes performing a calibration process for the air data probe prior to installation of the air data probe on a vehicle (block <NUM>). The method <NUM> also performs an operational process after the air data probe is installed on the vehicle (block <NUM>). The method <NUM> computes residuals for individual pressure channels of the air data probe and an aggregated response function, based on outputs from the calibration process and the operational process (block <NUM>). The method <NUM> then stores and trends the residuals over time (block <NUM>), and evaluates a trendline for the residuals against threshold values (block <NUM>). The method <NUM> announces a message when a threshold value is exceeded, indicating that the health of the air data probe is compromised (block <NUM>).

<FIG> is a flow diagram showing further details of a method <NUM> for providing health management and assessment for a multi-function air data probe, according to one example implementation. The method <NUM> initially includes a calibration process <NUM> that is carried out prior to installation of the air data probe on a vehicle such as an aircraft. The calibration process <NUM> measures or calculates a calibration curve(s) of pressure versus AOA for a new probe (block <NUM>). The calibration process <NUM> then defines threshold values and associated actions (block <NUM>), and stores the calibration curve(s) and threshold values on the probe itself or on a vehicle where the probe is installed (block <NUM>). A ratio of specific heats, γ, are also stored in the same manner (block <NUM>).

The method <NUM> also includes an operational process <NUM> that is carried out after the probe is installed and functioning on the vehicle (e.g., aircraft). The operational process <NUM> measures the pressure response of the ports (e.g., five ports) on the probe versus AOA during operation of the vehicle (block <NUM>). The operational process <NUM> then finds a total pressure (PT), by curve fitting the measured pressure responses and calculating a maximum value (block <NUM>). The operational process <NUM> also measures static pressures from independent flange located static pressure (PS) sensors during operation of the vehicle (e.g., during flight) (block <NUM>). The operational process <NUM> then normalizes the measured responses for Mach number (finds Mach number independent response) (block <NUM>), by using the ratio of specific heats (from block <NUM>).

The method <NUM> then combines an output from the calibration process <NUM> with an output of the operational process <NUM> in an adder <NUM>. The output from adder <NUM> is used to compute residuals for individual pressure channels and an aggregated response function (block <NUM>), and the residuals are stored and trended over time (block <NUM>). The method <NUM> then evaluates a trendline against the threshold values (block <NUM>), which were defined in the calibration process <NUM> (at block <NUM>). The method <NUM> then announces a message on a digital bus (e.g. ARINC <NUM>), when a threshold is exceeded (block <NUM>), indicating that the health of the air data probe is compromised.

Further details of the calibration process and operational process for the air data probe follow.

In one example, the calibration process can be implemented by calibrating the air data probe in an open jet wind tunnel. The calibration process can create static pressure (PS) port calibration (CP) curves for the following exemplary Mach values: <MAT> The calibration process than calculates a calibration parameter (CA) for each Mach data set as a function of AOA. The calibrations process calculates curves of Port PS / PT free stream vs Mach freestream, and calculates curves of Port PS / PS free stream vs Mach freestream.

In a probe measurement mode (operational process), the CA value is calculated using ports nearest the highest PS measurement. The AOA is calculated from averaged CA calibration (across flight envelope Mach range). This mode curve fits Port PS and calculates a maximum value, and uses this as a first guess for PT. For a low Mach, the Mach is calculated from Port PS / PT free calibration curves, and AOA is re-calculated using the Mach to interpolate CA from calibration curves. For a high Mach, the PS is obtained from probe base flange statics and/or the aircraft statics, and the Mach is calculated. The PT free is re-calculated using AOA to interpolate from Port PS / PT calibration curves, and the Mach is re-calculated from PS / PT free calibration curves. The final Mach is then calculated from PT and PS.

The following equations can be used in the calibration process and the measurement mode: <MAT> <MAT> <MAT> <MAT> <MAT> where Cp is the difference between the as measured and ambient static pressure as a fraction of impact pressure; qc is the free stream impact pressure; Ps is the measured static pressure; PTamb is the free stream ambient total pressure; and PSamb is the free stream ambient static pressure.

<FIG> and <FIG> are graphical representations of sample calibration curves obtained over a range of AOA that is up to ± <NUM>° for a multi-function air data probe. In this example, the air data probe port locations are as follows: port <NUM> is located at -<NUM> deg AOA; port <NUM> is located at -<NUM> deg AOA; port <NUM> is located at <NUM> deg AOA; port <NUM> is located at +<NUM> deg AOA,; and port <NUM> is located at +<NUM> deg AOA. In this example, the five separate pressure measurements by the air data probe make it possible to create three separate calibration curves to fully span a ± <NUM>° range.

Curves can be generated for Mach = <NUM>, <NUM>,. <NUM> to meet the PT and AOA accuracy requirements for aircraft. <FIG> shows typical computational fluid dynamics (CFD) or wind tunnel calibration results for Mach <NUM>, and <FIG> shows typical CFD or wind tunnel calibration results for Mach <NUM>. The calibration parameter, CA, is calculated directly from the results. During operation, the individual pressure measurements can be cross-checked using the calibration curves to diagnose potential plugging and or pressure module failure.

A computer or processor used in the present systems and methods can be implemented using software, firmware, hardware, or any appropriate combination thereof, as known to one of skill in the art. These may be supplemented by, or incorporated in, specially-designed application-specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs). The computer or processor can also include functions with software programs, firmware, or other computer readable instructions for carrying out various process tasks, calculations, and control functions used in the present methods.

The present methods can be implemented by computer executable instructions, such as program modules or components, which are executed by at least one processor. Generally, program modules include routines, programs, objects, data components, data structures, algorithms, and the like, which perform particular tasks or implement particular abstract data types.

Instructions for carrying out the various process tasks, calculations, and generation of other data used in the operation of the methods described herein can be implemented in software, firmware, or other computer- or processor-readable instructions. These instructions are typically stored on any appropriate computer program product that includes a computer readable medium used for storage of computer readable instructions or data structures. Such a computer readable medium can be any available media that can be accessed by a general purpose or special purpose computer or processor, or any programmable logic device.

Suitable processor-readable media may include storage or memory media such as magnetic or optical media. For example, storage or memory media may include conventional hard disks, compact discs, DVDs, Blu-ray discs, or other optical storage media; volatile or non-volatile media such as Random Access Memory (RAM); Read Only Memory (ROM), Electrically Erasable Programmable ROM (EEPROM), flash memory, and the like; or any other media that can be used to carry or store desired program code in the form of computer executable instructions or data structures.

Claim 1:
A multi-function air data probe (<NUM>, <NUM>), comprising:
a probe stem (<NUM>, <NUM>) having an outer surface that extends between a first end (<NUM>) and an opposite second end (<NUM>), the probe stem (<NUM>, <NUM>) having a first cross-sectional diameter;
a probe head (<NUM>, <NUM>) having an outer surface (<NUM>) that extends between a proximal end (<NUM>) and a distal end (<NUM>), wherein the proximal end (<NUM>) of the probe head (<NUM>, <NUM>) is coupled to the first end (<NUM>) of the probe stem (<NUM>, <NUM>), wherein the probe head (<NUM>, <NUM>) has a second cross-sectional diameter that is larger than the first cross-sectional diameter of the probe stem (<NUM>, <NUM>); and
a plurality of multi-hole ports (<NUM>) located in the probe head (<NUM>, <NUM>) with multiple sensor holes for each of the multi-hole ports, the multi-hole ports (<NUM>) extending into and through the probe stem (<NUM>, <NUM>);
wherein the outer surface (<NUM>) of the probe head (<NUM>, <NUM>) includes an array of sensor holes (<NUM>) that communicate with the multi-hole ports (<NUM>) in the probe head (<NUM>, <NUM>), wherein the array of sensor holes (<NUM>) is arranged in a set of sensor hole rows (<NUM>-<NUM> to <NUM>-<NUM>);
wherein the multi-hole ports (<NUM>) each include respective sensor manifold tubes (<NUM>) that respectively communicate with one of the sensor hole rows (<NUM>-<NUM> to <NUM>-<NUM>) through respective sets of multiple port tubes (<NUM>); and
wherein the air data probe (<NUM>, <NUM>) is configured to make measurements used to determine one or more of angle of attack values, total pressure values, and static pressure values.