A method, apparatus, and computer program product for identifying air data for an aircraft. The lift for the aircraft is identified. The number of surface positions for the aircraft is identified. The angle of attack during flight of the aircraft is identified. A synthetic dynamic pressure is computed from the lift, the number of surface positions, and the angle of attack.

Alternative method to determine the air mass state of an aircraft and to validate and augment the primary method

Apparatus and method for measuring the volume of a liquid in a fuel tank in a vehicle subject to varying external forces caused by movement or changes in the roll and pitch angles of the vehicle wherein the tank is mounted to the vehicle and subject to forces along the yaw axis of the vehicle. One or more tank load cells provides an output proportionally representing the load thereon. The load cells are placed between a portion of the tank and a portion of a reference surface of the vehicle and are sensitive along an axis that is substantially normal to the mounting surface and generally parallel to the yaw axis of the vehicle. A processor executes a derived relationship between the load cell output and the volume of fuel in the tank so as to convert the output signal from the load cell into output information representative of the volume of the fuel in the tank.

Method and apparatus for measuring the quantity of a liquid in a vehicle container

An apparatus, method and computer program product useful for supplying the pilot of an aircraft with aircraft attitude information in the event of full or partial failure of the gyroscopic system normally used to supply such data. The pitch angle, roll angle and heading angle estimates provided by the apparatus, method and computer program product can be displayed to the pilot thereby alleviating the requirement that the pilot mentally integrate such data from the remaining aircraft instruments.

Method, apparatus and computer program product for estimating airplane attitude with reduced sensor set

A turbulence data circuit for use in an aircraft The aircraft can include a radar system configured to transmit a first radio frequency wave and receive a second radio frequency wave and a display for receiving a display signal representative of turbulence The aircraft can further include a flight management system configured to determine a phase of flight, an aircraft inertial/air data system configured to determine an altitude and an airspeed The turbulence data circuit can include an interface for coupling to the radar system, the display, the flight management system, and the aircraft inertial/air data system The turbulence data circuit can be configured to determine the display signal representative of turbulence based on at least one of the phase of flight, the altitude, the airspeed and the second radio frequency wave

System and method for on-board adaptive characterization of aircraft turbulence susceptibility as a function of radar observables

A resonator gyroscope comprises a reference laser generator to produce a reference light; a first slave light source to produce a first slave light locked to the reference light; a second slave light source to produce a second slave light locked to the reference light; a resonator coupled to said first and second light sources, the resonator having first and second counter-propagating directions and resonance tracking electronics coupled to the Sagnac resonator to generate a first beat frequency based on a first resonance frequency for the first counter-propagating direction, a second beat frequency based on a second resonance frequency for the second counter-propagating direction, and a third beat frequency based on a third resonance frequency for the second counter-propagating direction; wherein the rotational rate of the resonator gyroscope is a function of the first, second and third beat frequencies.

System and method for reducing laser phase noise in a resonator fiber optic gyroscope

An inertial reference system for determining the attitude and rate of change of attitude of a vehicle such as an aircraft is disclosed. Redundancy of the inertial reference system may be accomplished by replacement of one of the fiber optic gyroscopes of an otherwise dual fiber optic gyros installation with a low-cost reference IMU. Failure detection and isolation of a fiber optic gyroscope system may be accomplished with a low-cost reference IMU rather than with an additional fiber optic gyroscope. The information provided by the eliminated fiber optic gyroscope is synthesized from the output of the remaining fiber optic gyroscope and the output of the low-cost reference IMU.

Synthesized attitude and heading inertial reference

A passive ring resonator gyroscope comprising a single piece body having an integral first and second resonator cavity. The first resonator cavity contains a single frequency laser that provides a sharply tuned single frequency light source to the second resonator cavity. The single frequency light source is split to form first and second sources. The second resonator cavity is a passive high Q cavity with a closed second optical path. The two light sources are fed into the second resonator and propagate as CW and CCW beams within the second resonator. A first servo channel develops a first control signal to tune the frequency of the CW beam to a resonance peak. A second servo channel develops a second control signal to tune the CCW beam to its resonance peak. By converting both servo error outputs into frequency, the relative frequency difference between the CW and CCW beams are recorded as the frequency shift in response to the body rate rotation about the sensitive axis. The first and second control signals are algebraically added to provide a linear laser difference servo signal which is integrated, to provide a passive cavity servo signal or, in an alternative embodiment, a laser cavity servo signal. The passive cavity servo signal is used to drive a passive cavity PZT to tune the passive cavity to be resonant at a center frequency midrange between the first and second offset frequencies. In the alternative embodiment, the cavity servo signal is used to adjust the linear laser path length to keep the linear laser center frequency at a frequency midrange between the first and second offset frequencies.

Sourced locked frequency modulated dual servo PRLG

A FOG design is disclosed that eliminates the need for spatially averaging the output of a readout optical fiber by using a short coherence length light source and decorrelating the orthogonal fiber modes in the birefringent readout optical fiber prior to them being received by the photodetector. The orientation of the optical output of the readout optical fiber with respect to the photodetector is at an angle other than normal incidence, which is designed to reduce the reflections from the photodetector back into the readout optical fiber. The coherence length of the source and the length and birefringence of the readout optical fiber are selected so that there is a complete decorrelation of the polarization states of the light as they pass through the readout optical fiber.

Fiber optic gyro with reduced readout reflection coupling characteristics

A passive ring resonator gyroscope comprising a single piece body having an integral first and second resonator cavity. The first resonator cavity contains a single frequency laser means to provide a sharply tuned single frequency light source to the second resonator cavity. The single frequency light source is sharply tuned and is split to form first and second sources. The second resonator cavity is a passive high Q cavity having a closed second optical path. The two light sources are fed to the second resonator and propagate as CW and CCW beams within the second resonator. A first servo channel tunes the frequency of the CW beam to a resonance peak. A second servo channel tunes the CCW beam to its resonance peak. By converting both servo error outputs into frequency, the relative frequency difference between the CW and CCW beams are recorded as the frequency shift in response to the body rate rotation about the sensitive axis. The first and second control signals are algebraicly added to provide a passive cavity path length difference servo signal which is integrated. A SECOND ADDER adds the integrated passive cavity difference signal to the reference signal (Fm) to provide the passive cavity path length servo signal to a passive cavity path length adjusting means for constantly adjusting the passive cavity path length servo signal to keep the passive cavity at peak resonance at a frequency substantially mid-range between the propagating (FCW) and the counterpropagating beams (FCCW).

Balanced dual servo VCO passive ring laser gyroscope

A combined angle-faceted, superluminescent diode and readout photodetector with an optical fiber coupled at one end of the superluminescent diode and the readout photodetector coupled at the other end wherein no fiber-optic couplers are used to couple the optical fiber with the readout photodetector.

James H. Doty

Papers

Synthesized attitude and heading inertial reference

Sourced locked frequency modulated dual servo PRLG

Fiber optic gyro with reduced readout reflection coupling characteristics

Balanced dual servo VCO passive ring laser gyroscope

Combined light source and readout for fiber-optic sensors with reduced back-reflections