Sicom, Inc.

Hemisphere Gps LLC

Hemisphere Gnss, Inc.

Intersil Americas Inc.

Csi Wireless Inc.

Bradley Paul Badke

Ronald Duane McCallister

Bruce Alton Cochran

Michael L Whitehead

Steven R Miller

John A McClure

Walter J Feller

Gregory J Durnan

Mark R Webber

An RF (e.g., GNSS) interference mitigation system and method uses a switchable bank of filters for selectively blocking signals in predetermined bandwidths based on detecting strong, interfering signals with an interference detection circuit including a sniffer antenna. A low-strength RF (e.g., GNSS) system can be combined with a spectrally-close high-strength, telecommunications receiver system for cooperative control. Alternatively, an RF receiver can detect tones, changes in DC bias or level changes to activate a filter selection switch.

RF (including GNSS) signal interference mitigation system and method

A GNSS system includes a receiver connected to an external mass storage device. Applications for the system, including GNSS data processing methods are also disclosed. The external storage device can comprise a flash (thumb) drive, which can be connected to the receiver via a USB interconnection.

GNSS receiver and external storage device system and GNSS data processing method

A constrained-envelope digital-communications transmitter circuit () in which a binary data source () provides an input signal stream (), a phase mapper () maps the input signal stream () into a quadrature phase-point signal stream () having a predetermined number of symbols per unit baud interval () and defining a phase point () in a phase-point constellation (), a pulse-spreading filter () filters the phase-point signal stream () into a filtered signal stream (), a constrained-envelope generator () generates a constrained-bandwidth error signal stream () from the filtered signal stream (), a delay element () delays the filtered signal stream () into a delayed signal stream () synchronized with the constrained-bandwidth error signal stream (), a complex summing circuit () sums the delayed signal stream () and the constrained-bandwidth error signal stream () into a constrained-envelope signal stream (), and a substantially linear amplifier () amplifies the constrained-envelope signal stream () and transmits it as a radio-frequency broadcast signal ().

Constrained-envelope digital-communications transmission system and method therefor

A multi-frequency down converter includes first and second signal paths. A common local oscillator/synthesizer drives both of the signal paths. Exemplary applications include GNSS systems operating across superbands. The down converter is adapted for use in a GNSS receiver system.

GNSS superband ASIC with simultaneous multi-frequency down conversion

A method and system of synchronizing multiple tracking devices in a geo-location receiver system comprising: receiving a first plurality of geo-location signals with a first tracking device; and receiving a second plurality of geo-location signals with a second tracking device. The method also includes: enabling the first tracking device as either a master tracking device or a master-with-mark tracking device; enabling the second tracking device to operate as a slave tracking device; the master tracking device generates and transmits a timing signal to the slave tracking device; and the master-with-mark tracking device is configured to receive an external input for synchronization and generates and transmits a timing signal to the slave tracking device. The method also includes acquiring the first plurality of geo-location signals and the second plurality of geo-location signals at a substantially simultaneous instant of time.

Method and system for synchronizing multiple tracking devices for a geo-location system

A digital communications system ( ) employs a rotationally invariant phase point constellation ( &Prime;) in a modulator ( ) thereof and a corresponding carrier phase acquisition phase locked loop ( ) in a demodulator ( ) thereof. The phase point constellation ( ) is rotationally invariant and the demodulator ( ) is able to achieve carrier phase synchronization due at least in part to the inclusion of phase point voids ( ) positioned in the phase point constellation ( &Prime;). Pragmatic encoding is employed with differential encoding ( ) only on non-convolutionally encoded bits. The phase point constellation ( &Prime;) provides identical codes for convolutionally encoded bits ( ) of phase points ( ) having equal magnitude that are rotated 90&deg;, 180&deg; and 270&deg; degrees from one another. Specific constellations of 256, 64 and 16 points are disclosed.

Rotationally invariant digital communications

A constrained-envelope digital-communications transmitter circuit ( ) includes a binary data source ( ) that provides an input signal stream ( ) to a modulator ( &prime;). The modulator ( &prime;) includes a pulse-spreading filter ( ) that filters a phase-point signal stream ( ) or a composite signal stream ( ) into a modulated signal ( ). A constrained-envelope generator ( ) generates a constrained-bandwidth error signal stream ( ) from the modulated signal ( ), and a delay element ( ) delays the modulated signal ( ) into a delayed modulated signal ( ) synchronized with the constrained-bandwidth error signal stream ( ). A complex summing circuit ( ) sums the delayed modulated signal ( ) and the constrained-bandwidth error signal stream ( ) into an altered modulated signal ( ), and a substantially linear amplifier ( ) amplifies the altered modulated signal ( ) and transmits it as a radio-frequency broadcast signal ( ).

Constrained-envelope transmitter and method therefor

A digital communications modulator (10) includes a low speed IC (12) which performs encoding, symbol generation, pulse shaping, interpolation, linearization, and small amounts of frequency tuning. A complex, baseband digital communications signal (34) is output from the low speed IC (12) as a plurality of parallel streams of digital words. In a digital tuner 14 which includes a high speed IC (20), these parallel streams are digitally combined and digitally up-converted to an IF digital data stream (68) that may have a center frequency many times the baud rate. The high speed IC (20) also converts the digital stream to a broadband analog signal (40). The broadband analog signal (40) is processed through an analog band pass filter (42) that removes spectral images, reduces quantization errors, and limits the bandwidth approximately to the baud rate.

Digital tuner

A constrained-envelope digital-communications transmitter circuit (22) in which a binary data source (32) provides an input signal stream (34), a phase mapper (44) maps the input signal stream (34) into a quadrature phase-point signal stream (50) having a predetermined number of symbols per unit baud interval (64) and defining a phase point (54) in a phase-point constellation (46), a pulse-spreading filter (76) filters the phase-point signal stream (50) into a filtered signal stream (74), a constrained-envelope generator (106) generates a constrained-bandwidth error signal stream (108) from the filtered signal stream (74), a delay element (138) delays the filtered signal stream (74) into a delayed signal stream (140) synchronized with the constrained-bandwidth error signal stream (108), a complex summing circuit (110) sums the delayed signal stream (140) and the constrained-bandwidth error signal stream (108) into a constrained-envelope signal stream (112), and a substantially linear amplifier (146) amplifies the constrained-envelope signal stream (112) and transmits it as a radio-frequency broadcast signal (26).

Constrained-envelope digital-communications transmission system and

An interference-tolerant spread-spectrum receiver (20) includes an FIR (finite impulse response) filter network (32) and a correlator/detector (34). The filter network (32) contains a pair of FIR filters (36) substantially identical to each other. A signal passes directly into the first filter (36'), but is delayed a predetermined amount of time before passing into the second filter (36'). Each of the filters (36) contains means for sampling (62) and windowing (70) the signal in the time domain; transforming (118) the signal to the frequency domain; limiting (130) and despreading (160) the signal in the frequency domain; and transforming (168) the signal back to the time domain. The signal from the first filter (36') is delayed the predetermined amount of time to resynchronize signals from both filters (36), which signals are then combined into a single signal. The combined signal is then passed into the correlator/detector (34), which determines the presence or absence of a spread-spectrum signal.

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Chandler, AZ, United States of America

Bradley Paul Badke