Abstract: Apparatus for rejecting multipath reply signals received from a target transponder within a selectable time period, comprising: a top antenna and a bottom antenna to detect reply signals; means for determining an altitude code associated with each reply signal detected by the antennas respectively; means for determining a differential time of arrival (DTA) value for each reply signal detected by the antennas respectively; and processing means for: 1) producing, for each top antenna reply signal, a top antenna target report that includes the altitude code and DTA values; 2) producing for each bottom antenna reply signal, a bottom antenna target report that includes the altitude code and DTA data; and 3) comparing each top antenna report data with corresponding data from each bottom antenna report, and marking out each bottom antenna report that is a multipath reply based on such comparison.

Abstract: Apparatus and method for detecting rotation of a shaft include a first antenna for transmitting electromagnetic energy into the shaft, a second antenna disposed for rotation with the shaft for modulating electromagnetic energy passing through the shaft in relation to the shaft rotational speed, and a detector for detecting the modulated electromagnetic energy that passes through the shaft.

Abstract: Apparatus for determining static torque on a rotatable shaft includes at least two elements that when coupled to the shaft have a torque dependent relationship to each other; a sensor for detecting the torque dependent relationship when the shaft is under static load; and means for rotating the sensor about the shaft under static load and through an arc that is less than a full rotation about the shaft.

Abstract: Embedded smart structures include active electronics which control and collect data from sensors and actuators and transmit data to the exterior of a body by electromagnetic antenna radiation to a conformal power and data interrogation interface. Multiple embedded smart structures are powered and interrogated by a network of conformal powering and interrogation units. Multiple embedded sensors each having an antenna with a defined narrow band resonant frequency are powered and interrogated by a single external powering and data interrogation antenna.

Abstract: Apparatus for contactless interrogation of an sensor integrally disposed with a structure including a pair of coils for coupling signals across a gap between a sensing circuit having a sense coil and an interrogation circuit having an exciter coil connectable to a variable frequency supply, the sensing circuit comprising a circuit for changing current through the sense coil in relation to the sensor output; the interrogation circuit comprising a circuit for detecting current in the exciter coil induced by the sense coil current; and control means for determining the sensor output based on the exciter coil current compensated for the gap.

Abstract: An apparatus and method of wavelength detection and parameter sensing uses a variable magnetic field applied to a Faraday effect thin magnetizable film to perform spectral analysis based on detected intensity distribution of diffracted light for known magnetic field strengths. The strength of the applied magnetic field can also be varied by change in a physical parameter relative to a fixed magnet in a magnetic circuit which generates a magnetic field about the grating to produce diffracted wavelengths which correspond to the parameter which influences the magnetic circuit.

Abstract: An optic sensor system comprising N optic sensors, each of the N sensors operating with received input light and providing output light having a characteristic corresponding to a sensed parameter; a number, less than N+2, of devices wherein each of the devices operates as a light source and as a light detector such that one device can be used to transmit interrogation light to two of the sensors, with two other of the devices being used to receive output light from the interrogated sensors; and optic waveguide means for transmitting light between the sensors and the devices.

Abstract: A programmed PWM controller for controlling an inverter is provided which includes memory means for storing a plurality of drive data words representing a pulsewidth modulation sequence, each drive data word including a driveword and a drivetime word, the drivewords being used to operate the inverter; first digital means for selectively retrieving each of the plurality of drive data words from the memory means according to the pulsewidth modulation sequence in response to a next drive data word request signal; and second digital means governed by the drivetime word for generating the next drive data word request signal.

Abstract: A proximity detector apparatus that uses the Faraday Effect to detect position changes of a target. The proximity detector includes a permanent magnet having a magnetic field that changes as the target moves to or from a predetermined position. A self-referencing optical sensor is provided that detects the changed magnetic field. The optical sensor includes a magneto-optic material positioned near a node of the magnet. Means are provided to transmit polarized interrogation light along an optical path that includes the magneto-optic material. The optical path is bi-directionally addressed and is non-reciprocal. The optical sensor transduces the changed magnetic field into a modulation of the interrogation light's intensity. Means are provided to detect variations in the interrogation light intensity and to determine a ratio such as the difference over the sum ratio for two interrogation light samples that traveled the optic path in opposite directions.

Abstract: Ultrasonic fuel gauging apparatus for a fuel tank having a plurality of ultrasonic fuel level sensors for sensing fuel levels at respective predetermined locations in a tank based on echo ranging; a memory means for storing sensor data; and a state device for interrogating each of the sensors by controlling the application of transmit pulses to each of the sensors and for receiving output signals corresponding to return echoes, the state device operating in response to a sequential state counter.

Abstract: An optical point level sensor for fluids includes a prism exposable to a fluid such that electromagnetic energy is reflected internally the prism dependent on the fluid level; and a lens optically connectable to an electromagnetic energy source and an electromagnetic energy detector such that electromagnetic energy from the source enters the lens at a first location axisymmetric to a second location where electromagnetic energy exits the lens to the detector. In one embodiment the lens is a GRIN lens.

Abstract: A liquid gauging system for a liquid container, the system comprising sensor means for producing a first electromagnetic signal that corresponds to liquid quantity in the container, and remote interrogation means for receiving the first electromagnetic signal and producing a system output that corresponds to the liquid quantity; the sensor means being energized by a second electromagnetic signal transmitted by the remote interrogation means.

Abstract: Methods and apparatus for detecting and decoding transponder reply signals of the type having a plurality of associated time discrete pulses including two bracket pulses and a number of related data pulses that may have been transmitted at discrete data time intervals between the bracket pulses such that the signal content detected during the data time intervals corresponds to the reply signal data code, comprising receiver means for receiving the reply signals and producing in-phase (I), quadrature (Q) phase and video (V) signals for each received pulse; means for detecting received pulses and storing the I/Q/V signals in a first memory; means for storing in a second memory pointer values that correspond to the temporal location of pulse I/Q/V signals in the first memory; means for identifying, based on time of arrival (TOA) values, pairs of potential bracket pulses wherein each pair marks the beginning and end of a reply code; and processor means for 1) determining an angle of arrival (AOA) value for each d

Abstract: A gauging system for a fluid tank includes means for determining fluid pressure data for the tank; means for determining acceleration data of the tank; and means for determining quantity of fluid in the tank as a function of the pressure and acceleration data. A method for determining quantity of fluid in a tank is also provided and includes the steps of:a. determining an orientation vector for each of a plurality of sensing areas of the tank;b. producing an output corresponding to pressure of the fluid on each of the respective sensing areas;c. determining an acceleration vector of the tank; andd. calculating quantity of fluid in the tank as a function of the pressure output signals, the orientation vectors and the acceleration vector.

Abstract: An intrusive mounting arrangement for an acoustic sensor includes an acoustic window and a flange assembly for mounting the sensor and window on a fluid tank, the flange assembly having a body portion configured to extend through an opening in the tank wall in a fluid-tight manner into the tank interior, the flange assembly having a body flange that is attachable to the tank wall; the body portion having a fluid passageway therein and a port that permits fluid in the tank to flow into the passageway; the flange assembly further comprising means for retaining the acoustic window in the passageway; the sensor comprising a body that is insertable in the fluid passageway in a fluid-tight manner; the sensor further comprising an active surface acoustically coupled to the window by fluid when the sensor is fully inserted in the passageway.

Abstract: Apparatus for igniting fuel in a combustor having at least one fuel nozzle that emits an atomized fuel spray into a primary zone of the combustion chamber comprising a laser energy source for producing infrared laser energy and optic fiber means for transmitting the laser energy from the laser source into the primary zone of the combustor to ignite the fuel spray. In one embodiment the laser igniter is disposed in a main fuel nozzle of the combustor.

Abstract: A proximity detector apparatus that uses the Faraday Effect to detect position changes of a target. The proximity detector includes a permanent magnet having a magnetic field that changes as the target moves to or from a predetermined position. A self-referencing optical sensor is provided that detects the changed magnetic field. The optical sensor includes a magneto-optic material positioned near a node of the magnet. Means are provided to transmit polarized interrogation light along an optical path that includes the magneto-optic material. The optical path is bi-directionally addressed and is non-reciprocal. The optical sensor transduces the changed magnetic field into a modulation of the interrogation light's intensity. Means are provided to detect variations in the interrogation light intensity and to determine a ratio such as the difference over the sum ratio for two interrogation light samples that traveled the optic path in opposite directions.

Abstract: An intrusive fluid sensor mounting arrangement for a fluid container includes first and second tubes, the first tube being attachable to a wall of the container such that a first end of the first tube is open to the container exterior through the container wall and a second end of the first tube extends into the container; the second tube being sized to slide axially within the first tube between first and second positions; the second tube having a first end accessible from outside the container such that a sensor can be installed in and removed from the second tube; the second tube providing fluid communication between the sensor and fluid in the container when the second tube is in the first position, and substantially preventing fluid loss from the container when the second tube is in the second position.

Abstract: A circuit that electronically simulates a capacitor includes a differentiator and a current source. In the preferred embodiment, the differentiator includes a differentiating gain amplifier that produces an output signal in response to an applied input signal, with the output signal being proportional to the time rate of change of the input signal. The differentiator further includes a variable inverting gain stage that produces a reference signal that has a desired phase relationship with respect to the input signal, such as a ninety degree leading phase for sinusoidal input signals. The variable gain stage is also used to provide for different simulated capacitance values, and to compensate for variations in the differentiator fixed value component. The current source is preferably a high output impedance current source such as a Howland current pump.

Abstract: An optical wavelength detector includes a photoelectric device that produces a signal in response to incident light thereon corresponding to a characteristic of the incident light such as wavelength. A light source is provided that can selectively expose light to the photoelectric device. A memory device stores device characterization data that corresponds wavelength information to current ratio signals from the photoelectric device. The current ratio signals are digitized and form part of the address for the memory. In a temperature compensated embodiment, the optical wavelength detector includes means to determine a temperature dependent electrical characteristic of the photoelectric device. In the preferred embodiment this electrical characteristic is the forward bias voltage detected when a predetermined forward bias current is applied to the photoelectric device in the dark.