Abstract: An apparatus for calibrating a radar altimeter is described. The altimeter provides an angle to a target based on radar energy received at right, left, and ambiguous antennas. The apparatus comprises a turntable on which the radar is mounted, a turntable controller which controls positioning of the radar altimeter, a radar energy source receiving transmit signals from the radar altimeter, a reflector, and a calibration unit. The reflector reflects and collimates radar energy from the radar source towards the radar altimeter. The calibration unit receives an angle from the controller indicative of a position of the radar altimeter with respect to the collimated radar energy and a measured angle from the radar altimeter. The calibration unit calculates a correction based on differences between the angle received from the turntable and the measured angle received from the altimeter and provides the calibration correction to the altimeter.

Abstract: A method for suppressing ground return radar fading in a radar altimeter is described. The method includes providing a radar gate width which corresponds to an area that is smaller than an antenna illumination area being impinged by transmissions of the radar altimeter, dithering the radar gate viewing area within the antenna illumination area being impinged by transmissions of the radar altimeter, and taking radar return samples with the radar altimeter.

Abstract: An apparatus for controlling an amplitude of a signal generated from a digitized sinusoid of rapidly and widely varying amplitude is described herein. The apparatus includes a two stage gain adjuster which produces a gain adjusted signal, a phase shifter which converts the gain adjusted signal into two gain adjusted output signals separated in phase by 90 degrees, a power estimation unit to estimate the power of the gain adjusted signal, and an adjusting unit to adjust a gain of the gain adjuster according to a power estimate from the power estimation unit and a desired output signal power.

Abstract: A method for reduces the sticking of proof masses in micro-electromechanical systems (MEMS) devices to sense plates in the MEMS device due to acceleration forces to which the MEMS device is subjected. The method includes determining a beginning of acceleration events which would cause proof masses to contact sense plates, reducing sense bias voltages to the sense plates, determining an end of the acceleration event, and increasing sense bias voltages to their former levels.

Abstract: A method for installation alignment of an inertial reference unit (IRU) with vehicle axes when the IRU is installed within the vehicle is provided. The vehicle axes include roll, pitch, and yaw axes. The method includes recording vehicle angular position data including roll and pitch, using an angular position measurement device with the vehicle being in a starting position, recording IRU data including roll and pitch, receiving measured nose plunge data, computing initial roll and pitch misalignment corrections, applying initial roll and pitch misalignment corrections to measured nose plunge data. A nose plunge yaw misalignment is determined using corrected nose plunge data and utilized to adjust the assumed heading reference.

Abstract: A method of manufacturing a microactuator device includes a plurality of generally parallel thin flexible sheets bonded together in a predetermined pattern to form an array of unit cells. Preferably, each of the sheets has only a single electrode layer located on one side of the sheet. Pairs of such sheets are then bonded together at spaced bonding locations with the electrode layers facing one another. Several sets of such sheet pairs can then be bonded together to form a microactuator device.

Abstract: A phase processor is disclosed which is configured to receive processed radar return data from a left radar channel, a right radar channel, and an ambiguous radar channel. The phase processor comprises a plurality of phase detectors each with an input and a reference input. The phase detectors are configured to determine a phase difference between radar return data received at the input and radar return data received at the reference input.

Abstract: A position determining apparatus including a magnet that is attached to a movable member which moves along a defined path of finite length. An array of distributed bridge sensors are located adjacent to the predefined path. The distributed bridge sensors each have one or more magneto-resistive elements positioned at a first location along the defined path of the magnet, and one or more other magneto-resistive elements positioned at a second location along the defined path. The magneto-resistive elements at the first location experience a different magnetic field component than those at the second location. The distributed bridge sensors produce an increased linear range relative to non-distributed bridge sensors of the prior art.

Abstract: A filter, includes a first order band pass filter configured to process non-zero amplitude gated radar return samples and process a portion of received zero amplitude return samples. The filter also calculates past filter outputs based on filter outputs generated during previous non-zero gated radar return samples.

Abstract: A method for determining a position of a doppler radar target in aircraft body coordinates is described. The method includes calculating values for doppler circle equations, in doppler coordinates, based upon a range to the target, a vehicle velocity, and a center frequency and bandwidth of a doppler swath filter. Further, an interferometric circle in body coordinates is calculated based upon a range to the target, and an interferometric angle. The doppler circle equations are transformed into body coordinates utilizing received pitch, roll and yaw information. Finally, an intersection of the interferometric circle equations with the transformed doppler circle equations is calculated, the intersection being the position of the target in body coordinates.

Abstract: A global positioning system for use with a plurality of transmitting satellites is disclosed wherein a full position solution is obtained from a number N of satellite transmissions and a plurality of sub-solutions each based on a different number (N−1) of satellite transmissions are obtained to determine if a satellite is faulty. A plurality of sub-sub-solutions is then obtained based on a different combination of N−2 satellites with each combination containing the satellites of different sub-solutions and excluding one other satellite in addition. An examination of the sub-sub-solutions provides an indication of which one of the satellites is the failed satellite.