Deere + Company

Wei Yu

Richard Gerald Keegan

Mark Phillip Kaplan

David M Li

Brian C Goodrich

Ronald R Hatch

A demodulator comprises a first-stage carrier demodulator and a second-stage carrier demodulator. The first-stage carrier demodulator is configured to remove or compensate for the tracking error in the baseband signal, where the tracking error comprises aggregate, channel tracking error of carrier phase for the same received band, sub-band, (baseband) GNSS satellite channel, or set GNSS channels. The second stage carrier demodulator is configured to remove or strip a carrier signal component without any unwanted image or carrier-related frequency artifacts and to prepare for correlation-based decoding or demodulation of the encoded baseband signal by the correlators. First correlators are configured to determine correlations for code phase tracking loop, where the code phase tracking loop is configured to estimate a corresponding code error component of the tracking error for the code local oscillator for a respective channel. Secondary correlators are configured to determine correlations for a carrier phase tracking loop, where the carrier phase tracking loop configured to estimate a corresponding aggregate feedback error for multiple channels or a set of channels.

Satellite navigation receiver with aggregate channel digital baseband processing

A wideband interference mitigation module is coupled to an output of a primary downconverter to process the digital intermediate frequency signal. A selective filtering module is associated with a secondary downconverter that comprises a digital harmonic-resistant translator. The selective filtering module comprises: (a) a low-pass filter that is configured as an anti-aliasing digital filter consistent with a target receive bandwidth to suppress aliasing associated with the analog-to-digital conversion, and (b) narrow band rejection filter to filter the digital baseband signal to reduce or to mitigate electromagnetic interference, where the narrow band rejection filter is configured for adaptive control responsive to detection by the wideband interference mitigation module of certain interference in the received radio frequency signal.

Multi-constellation, multi-frequency GNSS system for interference mitigation

A controller is configured to control the adaptive notch filter and to execute a search technique (e.g., artificial intelligence (AI) search technique) to converge on filter coefficients and to recursively adjust the filter coefficients of the adaptive notch filter in real time to adaptively adjust one or more filter characteristics (e.g., maximum notch depth or attenuation, bandwidth of notch, or general magnitude versus frequency response of notch).

Adaptive narrowband interference rejection for satellite navigation receiver

A selective filtering module is arranged to filter or process the digital baseband signal consistent with a target receiving bandwidth, where the selective filtering module comprises a narrowband rejection filter and wide-band filter configured to reject an interference component that interferes with the received radio frequency signal. The narrowband rejection filter is configured to reject a first interference component, where the narrowband rejection filter comprises an adaptive notch filter (NF). The wide band rejection filter is configured to reject a second interference component in accordance with a pulse blanking technique. An electronic data processor is adapted to control one or more filter coefficients of narrowband rejection filter and the wide band rejection filter in accordance with one or more strategic filter control factors among ADC saturation, activation/deactivation of the notch filter, and a wide-band spectrum analysis.

Adaptive narrowband and wideband interference rejection for satellite navigation receiver

A method is provided for acquiring a signal from a satellite in a global navigation satellite system. The signal includes a pseudorandom code. The method includes, for each time period of a plurality of time periods: generating samples of the signal, segments of the samples of the signal are correlated with a local copy of the pseudorandom code, thereby producing correlation values for the time period. A discrete Fourier transform is performed using, as inputs, the correlation values for the respective time period, thereby producing a frequency representation of the correlation values for the time period. The frequency representations of the correlation values for the plurality of time periods are combined according to a data hypothesis. When a magnitude of the combined frequency representations meets predefined criteria, a frequency corresponding to the magnitude is selected as a tracking frequency for the satellite.

Methods and devices for global navigation satellite system (GNSS) signal acquisition

A multi-band satellite navigation receiver for carrier and code tracking using a fixed point sigma rho filter with improved stability is described. The receiver simplifies and speeds up the data processing in the filter to adaptively accommodate common information from aggregate bands and obtain the accurate position of the receiver in real time. The filter may utilize a standard deviation function and a cross correlation function while determining adaptive scale factors to ensure that the filter is stable and reliable.

Satellite navigation receiver with fixed point sigma rho filter

Satellite navigation receiver with fixed point sigma RHO filter

A data processor selects a set of BOC correlations in accordance with a BOC correlation function for the sampling period if the primary amplitude exceeds or equals the secondary amplitude for the sampling period. The data processor selects a set of QBOC correlations in accordance with a QBOC correlation function for the sampling period if the secondary amplitude exceeds the primary amplitude for the sampling period. The data processor uses either the BOC correlation function or the QBOC correlation function, whichever with greater amplitude, at each sampling period to provide an aggregate correlation function that supports unambiguous code acquisition of the received signal.

Method and receiver for receiving a binary offset carrier composite signal

A data processor selects a set of BOC correlations in accordance with a BOC correlation function for the sampling period if the primary amplitude exceeds or equals the secondary amplitude for the sampling period. An electronic data processor determines whether the receiver is operating in a steady-state mode by evaluating the detected primary amplitude. The data processor selects and/or processes a set of BOC correlations for the sampling period to track a carrier of the received composite signal if the receiver is operating in the steady-state mode. In one embodiment, the data processor forms a first code error using the selected BOC correlations with a first chip spacing to drive the code tracking.

Method and receiver for receiving a composite signal

Methods and apparatus are disclosed for ameliorating signal reception. An example method disclosed herein includes receiving a composite satellite signal comprising a desired signal component and an interference signal component, converting the received composite satellite signal to a digital received composite signal, receiving a first group of samples from the digital received composite signal, generating an interference estimate of the interference signal component based on the first group of samples, combining the interference estimate and a second sample belonging to a second group of samples to remove, partially or entirely, the interference signal component from the composite satellite signal, the first group of samples received prior to the sample belonging to the second group of samples, wherein the removal is generally independent of the code chip rate of the desired signal component and substantially retains the undistorted chip edge characteristics of the desired signal component.

Methods and apparatus for ameliorating signal reception

A data processor selects a set of BOC correlations in accordance with a BOC correlation function for the sampling period if the primary amplitude exceeds or equals the secondary amplitude for the sampling period. The data processor selects a set of QBOC correlations in accordance with a QBOC correlation function for the sampling period if the secondary amplitude exceeds the primary amplitude for the sampling period. The data processor uses either the BOC correlation function or the QBOC correlation function, whichever with greater amplitude, at each sampling period for carrier tracking. Further, the data processor, through combining two sets of BOC correlations with different chip spacings provides an alternative unambiguous code acquisition of the received signal.

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Torrance, CA, United States of America

Wei Yu