Abstract: The present invention relates to a remote meter reading method and system of the type that may be poled by wireless communication. Other remote reading systems require a periodic change of batteries used to supply the power to the communication and other systems used in the remote meters. The present invention mitigates this need by using the water and gas flow into homes or other buildings to generate power used to recharge those batteries.

Abstract: The present invention relates to a remote meter reading method and system of the type that may be poled by wireless communication. Other remote reading systems require a periodic change of batteries used to supply the power to the communication and other systems used in the remote meters. The present invention mitigates this need by using the water and gas flow into homes or other buildings to generate power used to recharge those batteries.

Abstract: A system and method for determining the location of the phase center of an antenna are provided. For the transverse location of the phase center, the system may include radio frequency (RF) probes symmetrically surrounding the antenna's geometrical center to define RF probe pairs, a plurality of phase detectors for determining a phase difference between the signals detected by each pair and a processor for determining the transverse location of the phase center based upon probe position and the phase differences. For the longitudinal location of the phase center, the system may include first and second RF probes having a common transverse position, but being longitudinally separated, a phase detector for determining a phase difference between the signals detected by the probes and a processor for determining the longitudinal location of the phase center based upon the longitudinal separation and the phase difference.

Abstract: A system for determining a propellant content and a center of gravity in a three-axis stabilized spacecraft includes a ranging device that is coupled to an interior of a propellant tank of the spacecraft. The ranging device is configured to receive a ranging echo to facilitate determining a location of a membrane within the propellant tank.

Abstract: A system and method for determining the location of the phase center of an antenna are provided. For the transverse location of the phase center, the system may include radio frequency (RF) probes symmetrically surrounding the antenna's geometrical center to define RF probe pairs, a plurality of phase detectors for determining a phase difference between the signals detected by each pair and a processor for determining the transverse location of the phase center based upon probe position and the phase differences. For the longitudinal location of the phase center, the system may include first and second RF probes having a common transverse position, but being longitudinally separated, a phase detector for determining a phase difference between the signals detected by the probes and a processor for determining the longitudinal location of the phase center based upon the longitudinal separation and the phase difference.

Abstract: A method for controlling code power levels of individual codes of a composite quadrature phase shift keyed (QPSK) signal. The method may involve obtaining a sample of the composite QPSK signal; separating the individual codes from the composite QPSK signal; analyzing the individual codes against corresponding commanded code power settings for the individual codes; and determining a code power correction signal needed for each of the individual codes needed to adjust a code power for each of the individual codes to match their corresponding commanded code power settings.

Abstract: A system for determining a propellant content and a center of gravity in a three-axis stabilized spacecraft includes a ranging device that is coupled to an interior of a propellant tank of the spacecraft. The ranging device is configured to receive a ranging echo to facilitate determining a location of a membrane within the propellant tank.

Abstract: A system and method for determining the beam center location of an antenna, such as a global positioning system (GPS) antenna, are provided. A system for determining the beam center of an antenna may include a plurality of radio frequency (RF) probes, such as Integrated Transfer System (ITS) antenna elements, located at respective predefined positions surrounding the geometrical center of the antenna. The system may also include at least one detector configured to provide a measure of the RF power detected by each respective RF probe. The system may also include a processor configured to determine the beam center of the antenna based upon the predefined position of each RF probe and the measure of the RF power detected by each respective RF probe. A corresponding method is also provided.

Abstract: A GPS transponder system incorporating a phase error monitoring and compensation subsystem. The phase error monitoring and compensation subsystem includes a demodulator subsystem that demodulates modulated carrier signals being output from each one of a pair of GPS transponders to obtain the navigation codes being generated by each of the transponders from their respective carrier signals. The navigation codes obtained from the modulated carrier signals are compared to separate navigation codes that are generated by a navigation data unit (NDU) of the system and supplied over a thermally stable signal transmission line. The signal transmission line has a known, fixed delay and is not affected by temperature changes that affect the modulated carrier signals. A phase comparator subsystem uses the comparison to generate needed error correction signals that are applied via phase shifters to each of the transponders.

Abstract: A system and method for determining the beam center location of an antenna, such as a global positioning system (GPS) antenna, are provided. A system for determining the beam center of an antenna may include a plurality of radio frequency (RF) probes, such as Integrated Transfer System (ITS) antenna elements, located at respective predefined positions surrounding the geometrical center of the antenna. The system may also include at least one detector configured to provide a measure of the RF power detected by each respective RF probe. The system may also include a processor configured to determine the beam center of the antenna based upon the predefined position of each RF probe and the measure of the RF power detected by each respective RF probe. A corresponding method is also provided.

Abstract: A method for controlling code power levels of individual codes of a composite quadrature phase shift keyed (QPSK) signal. The method may involve obtaining a sample of the composite QPSK signal; separating the individual codes from the composite QPSK signal; analyzing the individual codes against corresponding commanded code power settings for the individual codes; and determining a code power correction signal needed for each of the individual codes needed to adjust a code power for each of the individual codes to match their corresponding commanded code power settings.

Abstract: A GPS transponder system incorporating a phase error monitoring and compensation subsystem. The phase error monitoring and compensation subsystem includes a demodulator subsystem that demodulates modulated carrier signals being output from each one of a pair of GPS transponders to obtain the navigation codes being generated by each of the transponders from their respective carrier signals. The navigation codes obtained from the modulated carrier signals are compared to separate navigation codes that are generated by a navigation data unit (NDU) of the system and supplied over a thermally stable signal transmission line. The signal transmission line has a known, fixed delay and is not affected by temperature changes that affect the modulated carrier signals. A phase comparator subsystem uses the comparison to generate needed error correction signals that are applied via phase shifters to each of the transponders.

Abstract: A security system suitable for retail establishments carrying articles comprises tags for affixing to the articles, the tag being capable of generating a responsive microwave signal in response to a microwave detection signal; and at least one transceiver for generating the microwave detection signal and for receiving the responsive microwave signal.

Abstract: A crystal oscillator including a laser light source for emitting a laser beam to an aligned quartz crystal coupled to an oscillator circuit by an optical feedback network. The optical feedback network is responsive to variations of misalignment of the laser beam with the crystal and correction signals generated for introduction back to the crystal to bring its frequency back to a constant standard frequency output.

Abstract: Circuits are disclosed for normalizing a device which has a current-controlled frequency response, such as a YIG or a TWM device, to a predetermined current-frequency (I-F) characteristic in order that a device equipped with such a circuit can be preadjusted for substitution in a system for a like device without realigning the system. The normalizing circuit is in parallel with the device, and is comprised of a transistor and a compensating current-sensing resistor in series with the transistor. A shunt compensating current, I.sub.C, through the transistor is set by a voltage on a potentiometer to offset the I-F characteristic of the composite device and circuit from that of the device to a predetermined level and also by a feedback control circuit connected to the compensating current-sensing resistor. The slope of the offset characteristic is then adjusted to a predetermined value by adjusting the gain of a feedback control circuit between the transistor and a resistor which senses a voltage, V.sub.