Measuring and testing – Navigation – Take-off and landing monitors
Reexamination Certificate
1999-04-08
2001-06-26
Oen, William (Department: 2855)
Measuring and testing
Navigation
Take-off and landing monitors
Reexamination Certificate
active
06250149
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a system and method for generating information which characterizes the movement of an object through a fluid, such as an aircraft during flight, using one or more flow sensors which are substantially flush-mounted within at least one surface of the object.
BACKGROUND INFORMATION
Aircraft typically include multiple systems for measuring physical parameters across various parts of the aircraft during flight, from which air flight data, including airspeed, altitude and airframe attitude (pitch and yaw) information, is typically derived. Such multiple systems may include an airframe data system which monitors physical parameters about the body, wings, tail, nacelle of an aircraft to provide an indication of airspeed, attitude, temperature, and static pressure about the aircraft; and an electronic engine control system provides data to regulate the air/fuel ratio distributed to each of the aircraft's engines. The prior art teaches supplementing the information gathered by one system with that of another. For example, in one known approach, the static pressure information provided by an airframe data system is supplemented by the temperature information provided by an engine control system.
Such prior art systems employ a wide variety of sensors, structures and techniques for gathering the desired physical parameter information, including nose-mounted booms, Pitot tubes and flush-mounted static pressure taps, and optical data systems. Each of these prior art systems has its deficiencies or disadvantages.
For example, nose booms, which are generally effective at providing airspeed and altitude information, typically include sensors for measuring static pressure, total pressure and temperature. However, nose booms reduce the aerodynamics of the aircraft, making them impractical to use during normal aircraft flight.
Pitot tubes are also generally effective at providing airspeed and altitude information by measuring static pressure, dynamic pressure and temperature about an aircraft. However, Pitot tubes can not be flush-mounted to the airframe of an aircraft and lose accuracy at speeds below about 20 m/s (about 66 ft/s). Flush-mounted static pressure taps sensor systems are typically mounted to the nose of an aircraft, as well as opposite sides of various aerodynamic surfaces, to measure static pressure, total pressure and differential pressures. Flush-mounted static pressure taps typically require the use of a remotely-located temperature sensor, and the placement of such taps in the nose of an aircraft may effect aircraft radar systems. And, as with Pitot tubes, systems employing flush-mounted static pressure taps similarly lose accuracy at speeds below about 30.5 m/s (about 100 ft/s).
Optical data systems are generally effective at generating airspeed and airframe attitude information by projecting a beam of light ahead of the aircraft. The beam is reflected by atmospheric particles back to an optical sensor. The optical system then infers airspeed and airframe attitude based on the beam measurements. Optical systems are not able to measure either pressure or temperature at the sensing location, requiring the use of additional sensors. Additionally, the electronics packaging for each optical sensor is larger and heavier than traditional sensor electronic packages, requiring additional structural modifications be made to support each optical sensor.
SUMMARY OF INVENTION
A system for generating information which characterizes movement of an object through a fluid, such as an aircraft moving through air during flight, includes at least one sensor module and, preferably, a plurality of sensor modules that are respectively mounted substantially flush with a plurality of respective aerodynamic surfaces of the aircraft. Each module includes a set of sensors mounted on or in the first surface of each module. The sensors generate signals representative of a plurality of physical parameters associated with fluid flow over the module's first surface and, hence, nominally over the aerodynamic surface at the module's location on the aircraft.
Each module minimally includes at least one flow sensor and, preferably, two flow sensors which generate a first and second signal representative of a flow rate of the fluid over the module's first surface along two orthogonal sensing axes, respectively, and a temperature sensor which generates a third signal representative of the temperature of the first surface. While the invention contemplates any suitable manner for mounting the sensors on or in the module's first surface, the sensors are preferably mounted on a first, common substrate which underlies the module's first surface to thereby place the module's flow sensors substantially flush with the aircraft surface.
In a preferred embodiment, each module includes electronic signal-conditioning and/or signal-processing components in electrical communication with each sensor. By way of example only, the electronic components may be conveniently mounted on a second, common substrate which is interconnected with the first sensor-supporting substrate using a flexible tape carrier having an electrically-conductive data bus defined therein. A first signal processor thus preferably receives the first, second and third signals and generates a fourth signal which minimally includes temperature-corrected flow rate information based on the first, second and third signals. In a constructed embodiment, wherein each sensor generates analog signals, each module further includes a digital-to-analog converter which converts the first, second and third analog sensor output signals to digital form; and the first signal processor digitally processes the first, second and third digitally-converted signals to generate the fourth signal, which is also a digital signal.
In a preferred embodiment, each module is in electrical communication with a remotely-located controller, for example, via a data bus on the aircraft external to the modules. The remotely-located controller periodically calls for and collects the fourth signal from each module. More specifically, when the controller calls for the fourth signal from a given module, the module's first signal processor transmits both the processor node address and the fourth signal along the tape carrier's data bus and the external data bus to the controller.
A second signal processor receives the collected fourth signals from the controller and calculates the desired movement-characterizing information, e.g., air flight data including relative airspeed and airframe attitude information, based on the collected fourth signals.
In accordance with another feature of the invention, in a constructed embodiment where the desired air flight data includes aircraft altitude information, at least one module includes a pressure sensor which generates a fifth analog signal representative of a static pressure acting on the module's first surface. Indeed, under the invention, where enhanced system operation is desired at airspeeds above those likely to cause saturation of each module's flow sensor, i.e., above perhaps about 153 m/s (about 500 ft/s), at least four modules and, most preferably, every module includes a pressure sensor which generates a fifth analog signal representative of a static pressure acting on each module's respective first surface. Preferably, the aircraft surface at the discrete locations at which the modules including pressure sensors are deployed is preferably nominally canted at an angle of about 12° to thereby provide a nominal pressure gradient on the module's first surface at level flight, whereby the repeatability of pressure sensor measurements is significantly improved.
In modules which include pressure sensors, the fifth signal is suitably conditioned and received by the first signal processor in a manner similar to that described above in connection with the first, second and third signals. The first signal processor then generates static pressure i
Brooks & Kushman P.C.
Oen William
The Boeing Company
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