Abstract: A vehicle navigation system uses a one-multiplier Gray-Markel filter. The sign parameter of each stage of the filter is selected by an algorithm which limits the maximum signal passing through the filter, thereby preventing overflow.

Abstract: A method and apparatus for real-time analysis and display of information to provide information which will enable a user to be continuously apprised of all objects within a predetermined radius from the user's location (a "sphere of interest") while at the same time establishing the user's position relative to a fixed reference system. The invention involves determining the location and orientation of the user relative to a fixed reference system (such as the earth), as well as the location and orientation of objects in the sphere of interest about the user. Display of this information is on a display format, which may be embodied on an optical medium such as a helmet visor, a heads-up display media, a projection surface or a user's eye.

Abstract: The STREAMER FOR RISC DIGITAL SIGNAL PROCESSOR shown herein allows a CPU 46 to interface with a memory 60 via data registers 50. Pre-fetch and post-store of the correct address is determined by an address generator 58 according to a rule determined by a context register 52. An index indicative of this address is stored in an index register 54. The data, context, and index registers together form a streamer 56, streaming data between the CPU 46 and data memory 60. The rule of the context register 52 also drives a converter 62 for converting data between memory format and register format. The speed and flexibility of a RISC device is combined with the intensive memory access of a digital signal processor.

Abstract: The present invention relates to a method and an apparatus for enhancing the optical image of information-containing symbols captured off reflective surfaces/using a conventional optical scanning camera. The method involves positioning the imaging assembly of the camera atop an information-containing coded symbol located on a component surface, where the imaging assembly includes a diffuser element and LED lighting array for illuminating the symbol, illuminating the surface and the symbol, and moving the diffuser element to a location between the coded symbol and the camera lens such that only light returning directly from the symbol is able to pass through the voided region of the diffuser element, before imaging the coded element.

Abstract: An accurate estimate of the amplitude of a sparsely sampled sinusoidal signal is obtained by filtering the squares of the sampled values of the sinusoidal signal with an adjustable notch filter in order to remove a double-frequency component at twice the frequency of the sinusoidal signal. This amplitude estimate, for example, is used for automatic gain control of the amplitude of the sinusoidal signal. Preferably, the notch filter is a digital filter for computing an output signal (v) from successive samples (x.sub.n, x.sub.n-1, x.sub.n-2) of an input signal (x) according to: v.sub.n =x.sub.n -.beta.x.sub.n-1 +x.sub.n-2. The frequency control parameter (.beta.) is computed, so as to automatically track the frequency of the sinusoidal signal, by integrating a product of a derivative (x.sub.n-1 -x.sub.n-2) of the input signal (x) and a derivative (v.sub.n -v.sub.n-1) of the filtered signal (v).

Abstract: For use with a quartz angular rate sensor, a frequency and phase-locked synthesizer recovers a reference signal virtually free of phase noise, and generates a quadrature-phase reference signal for complex demodulation of the angular rate signal. The synthesizer also ensures a precisely adjusted phase shift of approximately zero across the drive tines of the sensor. Moreover, the digital synthesizer provides a precise numerical indication of the drive frequency, which can be used for compensation and automatic tuning of filters, such as a tracking filter, a filter in an automatic gain control, and notch filters in the phase and/or frequency detectors in the digital synthesizer. The tracking filter is used as a pre-filter for the synthesizer, and is responsive to a passband-width control signal generated from the magnitude of the frequency and phase error signal controlling the frequency generated by the synthesizer.

Abstract: A single bit bandpass analog-to-digital converter has an analog summer, an analog bandpass filter, a single bit quantizer, and a single bit digital-to-analog converter connected in a loop. An input signal to the single bit filter is applied to a plus input terminal of the summer, and the output of the digital-to-analog converter is applied to a minus input terminal of the summer. The output signal from the single bit filter is taken from the output of the quantizer. The bandpass filter is preferably driven by a digital clock running at the same frequency as the quantizer and the digital-to-analog converter. This architecture reduces quantization noise within the passband at the possible expense of increasing it outside the passband. The passband is centered precisely on one-quarter of the clock frequency.

Abstract: A resonator produces a signal which is processed by being digitized and demodulated. The processed signal is applied to a filter having three sections. The first is a lowpass filter, the second is a decimator, and the third is an equalizer filter. The lowpass filter filters out the high frequency components which would be aliased by the decimator. The equalizer filter performs whatever processing as is appropriate for the measurement which is sought. A second or subsequent equalizer filter may be driven by the first. The lowpass filter and the equalizer filters all have the same architecture of allpass filters, weighting elements, and adders. The weights applied to the weighting elements vary to perform the varied purposes of the various filters. The filtered signal is applied to a display, such as a human operator, or a device (such as an auto-pilot) either in or out of a feedback loop, or both.

Abstract: An alerting process is presented that uses the steps of first receiving at least a first signal from a signal source for a predetermined short interval. The first signal is analyzed over the predetermined short interval to obtain the spectral energy of the first signal within contiguous incremental frequency bands that extend over the frequency spectrum of interest. The energy value obtained for each incremental frequency band is then stored as a short term integrated value in a memory at an address location corresponding to the incremental frequency. Successive short term integrated values are then integrated over a predetermined long term interval to obtain a long term integrated value for each respective incremental frequency band. Each short term integrated value is then divided by the corresponding long term integrated value to obtain an enhanced STI frequency value for each incremental frequency band.

Abstract: Information often modulates an underlying carrier signal, thereby producing a modulated information signal 70. This same carrier signal is required, with a few modifications, to demodulate the modulated information signal. This required signal is called the demodulator reference signal. It must be complex, that is, it must contain separate in-phase and quadrature outputs. A degraded version 10 of this signal is often available with the correct frequency, but with the wrong phase and amplitude, and with a direct current (dc) offset. The present invention 68 produces a digital demodulator reference signal 38, 46 from the degraded signal 10. It eliminates dc offset with a dc blocker 18, adjusts amplitude with a scaler 14, adjusts phase with a first Hilbert transformer 20, multipliers 26 and 28 and summer 34, and produces in-phase and quadrature outputs with a second Hilbert transformer 36 cascaded with the first.

Abstract: The invention is a contaminant removal system for purifying air. Incoming air is cooled to a cryogenic temperature. A vortex tube further cools the cooled air so as to solidify contaminants therein. A filter system then filters out the solidified contaminants from the air.Use of a vortex tube minimizes the amount of moving parts. This reduces maintenance and concommitant costs involved with operation. The present system has a long life. The vortex tube is relatively inexpensive.

Abstract: An electro-optical sensor system for use in observing objects. A staring sensor is provided which includes a staring array of mid-wave infrared (IR) detectors for providing real-time observations of objects. A preprocessor system is connected to the staring sensor for providing temporal filtration of the real-time observations. A remote control is provided for controlling the temporal filtration.

Abstract: A projectile which includes multiple warheads separated one from another within a casing, each warhead having its own independent detonator. The warheads are arranged in spaced relationship along the longitudinal axis of the casing, and the detonators are linked with a fuzing mechanism located at the forward region of the casing. Upon reaching the target, the rearmost warhead in the projectile is detonated and the remaining warheads are then detonated sequentially forwardly, ad seriatim, by the fuzing mechanism.

Abstract: This invention is an apparatus and method for determining a set of instantaneous values of optimum flight path for a gliding vehicle at any time t, by determining, at each time t, altitude and position information associated with the vehicle, and wind profile information as a function of the altitude of the vehicle; determining, at each time t, the effective glide slope ratio of the vehicle as a function of the altitude of the vehicle, and then integrating the effective glide slope ratio, at each time t, from the destination point toward the current position and altitude of the vehicle. The invention also contemplates converting such time-dependent value of optimum flight path into a set of control commands for control surface actuators on the vehicle.

Abstract: A digitally driven, analog bandpass filter has an analog summer and two analog delay elements connected in a loop. An input signal to the filter is applied to a plus input terminal of the summer, and the output of the second delay elements is applied to a minus input terminal of the summer. The output of filter may be taken either from the output of the summer, or from the output of the second delay element, or from any point in between. Each delay element is driven by a two phase non-overlapping clock, and each element passes a charge from a first capacitor through an op amp to either a second capacitor (first phase) or a third capacitor (second phase). Amplification may be provided by adjusting the ratio of the second (or third) capacitor to the first capacitor. If a differential op amp is used, both sides of the op amp are clocked together, and each side has its own trio of capacitors identical to the trio on the other side.

Abstract: This detector provides a computationally simple digital low power detector of symbol rate, also called baud rate. It uses an approximate Hilbert transform function to create approximate in-phase and quadrature signals. An approximate envelope detector (feature extractor) processes these signals to produce a signal with a strong frequency component at the symbol rate. This signal is then filtered, accumulated, and threshold detected. The approximate in-phase and quadrature signals are formed by a linear sequence of six delay elements, the output of the third delay element being the in-phase signal. A first summer receives the output of the second delay element at a minus input and the output of the fourth delay element at a plus input. A second summer receives the signal input at a minus input and the output of the sixth delay element at a plus input, and drives a right two bit shifter.

Abstract: A novel, high-altitude, solar powered aircraft, capable of staying aloft at high altitudes for many months or even years to conduct around the clock surveillance and/or reconnaisance, includes a forward wing with solar energy capturing cells, a rear wing, inflated pontoons for keeping the aircraft aloft, suspension wires attached to the pontoons, a gondola suspended from and connected to the wires, control apparatus for moving the gondola along the wires, shifting the weight of the aircraft and thereby enabling banking to optimize exposure of the solar cells to the rays of the sun. The gondola preferably contains a sensor suite, power generating and storage apparatus, and synthetic aperture radar imaging apparatus.

Abstract: A spatial power combiner includes a circularly corrugated horn 26, a meniscus lens 28, an amplifier array 16, and a layer of microwave absorbing material 34 on a housing interior 32. The lens 28 receives polarized microwave radiation from the horn 26 and collimates it, renders it in phase and with nearly uniformly amplitude, and distributes it across the lens aperture. The amplifier array 16 amplifies the radiation and re-radiates it, orthogonally polarized, to the lens 28, which focuses it back down the horn 26. An array of parasitic micropatches 24 between the lens 28 and amplifier array 16 provides impedance matching. A quarter-wave anti-reflecting coating 30 covers both surfaces of the lens 28. The microwave absorbing material 34 reduces or prevents resonance of higher order modes.

Abstract: Production of electrically conductive composites comprising a dielectric porous substance, e.g., fiberglass fabric, and a pyrrole polymer in the pores of such substance, by treating the porous substance with a liquid pyrrole, and then treating the resulting porous substance with a solution of a strong oxidant in the presence of a non-nucleophilic anion, such as ferric chloride. The pyrrole monomer is oxidized to a pyrrole polymer, which precipitates in the interstices of the porous material. Alternatively, the dielectric porous material can first be treated with a solution of strong oxidant and non-nucleophilic anion followed by treatment with liquid pyrrole, to precipitate an electrically conductive polypyrrole in the pores of the material. The resulting composite of porous material, e.g., fiberglass fabric, containing polypyrrole is electrically conductive while the other properties of such impregnated conductive porous material are substantially unaffected.