Leica Geosystems Ag

Signal Laboratories, Inc.

Mesc Electronic Systems, Inc.

Miroslaw Balodis

Hassan Zamat

Delbert Flagg

A GLONASS receiver and a corresponding method for its calibration for more precise carrier phase measurements. The receiver includes a conventional receiver channel ( ), having a bandpass filter ( ) for establishing the sampling bandwidth prior to digitizing a plurality of received satellite signals, each having a different frequency. The receiver also includes a calibration channel ( ) in which multiple satellite signals are bandbass filtered (in filter ) at a single intermediate frequency, to avoid errors resulting from group delay variation introduced by passing multiple satellite signals through a common bandpass filter. The calibration channel ( ) downconverts ( ) to the intermediate frequency, bandpass filters ( ), and then upconverts ( ) again. Each satellite signal in turn is processed in this manner by selecting appropriate difference frequencies for downconversion and upconversion. The calibration channel ( ) produces a set of reference carrier phase measurements that can be applied to correct errors in carrier phase measurements generated by the conventional receiver channels ( ).

Receiver calibration technique for global orbiting navigation satellite system (GLONASS)

A method of and apparatus for transmitting or receiving circularly polarized signals is disclosed. The technique employs a phase shifting network for connection between an antenna and a radio transmitter or receiver to produce a phase shift when transmitting or eliminate a phase shift when receiving. In one preferred embodiment, a dielectric substrate has a phase shifting network or printed circuit lines defining a signal transmission paths between a radio connection terminal and a plurality of antenna element connection terminals for coupling a multi-element antenna and a radio. Each transmission path is phase shifted relative to an adjacent path by a predetermined amount by each path having progressively equally different electrical length to provide equal phase shift of a radio frequency signal progressively through the transmission paths. Adjacent path pairs are progressively joined at combiner nodes of equal power division by shunt connection line segments to that the power at each antenna connection terminal is equal to the power at the radio connection terminal divided by the number (typically four) of antenna terminals.

Phase shifting network and antenna and method

A keyboard switch system for stenographic machines whereby electrical signals corresponding to key depression may be derived. The switch system is comprised of a plurality of coils each having a coil parameter effecting plunger coaxial therewith and spring loaded to an upper position. The coils are arranged in an assembly so as to be mountable in the stenographic machine with the plunger disposed so as to be contaced and depressed in response to depression of a respective key. Each of the coils form a part of a tuned circuit with plunger position affecting the resonant characteristics so as to create logic levels response to key position.

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Garden Grove, CA, United States of America

Miroslaw Balodis