The presence or absence of a preamble is detected with accuracy in a reception. apparatus that receives a signal including a preamble.

A reception section receives a subframe including a subframe preamble and a message and a frame including a frame preamble. A processing section performs a process of detecting the presence or absence of the subframe preamble according to whether or not a given relation holds between a reception timing of the subframe preamble and a reception timing of the frame preamble. A message decoding section extracts the message from the subframe and decodes the message in a case where the presence of the subframe preamble is detected.

Methods and apparatus for processing of GNSS data derived from multi-frequency code and carrier observations are presented which make available correction data for use by a rover located within the region, the correction data comprising: the ionospheric delay over the region, the tropospheric delay over the region, the phase-leveled geometric correction per satellite, and the at least one code bias per satellite. In some embodiments the correction data includes an ionospheric phase bias per satellite. Methods and apparatus for determining a precise position of a rover located within a region are presented in which a GNSS receiver is operated to obtain multi-frequency code and carrier observations and correction data, to create rover corrections from the correction data, and to determine a precise rover position using the rover observations and the rover corrections. The correction data comprises at least one code bias per satellite, a fixed-nature MW bias per satellite and/or values from which a fixed-nature MW bias per satellite is derivable, and an ionospheric delay per satellite for each of multiple regional network stations and/or non-ionospheric corrections. Methods and apparatus for encoding and decoding the correction messages containing correction data are also presented, in which network messages include network elements related to substantially all stations of the network and cluster messages include cluster elements related to subsets of the network.

Methods and apparatus for processing of GNSS data derived from multi-frequency code and carrier observations are presented which make available correction data for use by a rover located within the region, the correction data comprising: the ionospheric delay over the region, the tropospheric delay over the region, the phase-leveled geometric correction per satellite, and the at least one code bias per satellite. In some embodiments the correction data includes an ionospheric phase bias per satellite. Methods and apparatus for determining a precise position of a rover located within a region are presented in which a GNSS receiver is operated to obtain multi-frequency code and carrier observations and correction data, to create rover corrections from the correction data, and to determine a precise rover position using the rover observations and the rover corrections. The correction data comprises at least one code bias per satellite, a fixed-nature MW bias per satellite and/or values from which a fixed-nature MW bias per satellite is derivable, and an ionospheric delay per satellite for each of multiple regional network stations and/or non-ionospheric corrections. Methods and apparatus for encoding and decoding the correction messages containing correction data are also presented, in which network messages include network elements related to substantially all stations of the network and cluster messages include cluster elements related to subsets of the network.

In conditions in which Global Navigation Satellite System (GNSS) signal spoofing is likely occurring, a GNSS receiver may be operated in a reduced operational state with respect to one or more GNSS bands that are likely being spoofed. According to embodiments, a reduced operational state with regard to a GNSS band may comprise performing one or more of the following functions with respect to that GNSS band: disabling data demodulation and decoding, disabling time setting (e.g., time of week (TOW), week number, etc.) disabling acquisition of unknown/not visible satellites, disabling satellite differences, disabling error recovery, reducing non-coherent integration time, and duty cycling the power for one or more receiver blocks associated with the GNSS band.

A satellite signal reception device includes: a local signal generator that generates a signal while switching between a signal having a first local frequency corresponding to a first positioning satellite signal and a signal having a second local frequency corresponding to a second positioning satellite signal based on a reference clock signal; and a frequency converter that converts a reception signal of the first positioning satellite signal into a first intermediate frequency signal by multiplying the reception signal of the first positioning satellite signal by the signal having the first local frequency, and converts a reception signal of the second positioning satellite signal into a second intermediate frequency signal of which at least a part of a converted frequency band is in common with the first intermediate frequency signal multiplying the reception signal of the second positioning satellite signal by the signal having the second local frequency.

A satellite signal reception device includes: a local signal generator that generates a signal while switching between a signal having a first local frequency corresponding to a first positioning satellite signal and a signal having a second local frequency corresponding to a second positioning satellite signal based on a reference clock signal; and a frequency converter that converts a reception signal of the first positioning satellite signal into a first intermediate frequency signal by multiplying the reception signal of the first positioning satellite signal by the signal having the first local frequency, and converts a reception signal of the second positioning satellite signal into a second intermediate frequency signal of which at least a part of a converted frequency band is in common with the first intermediate frequency signal multiplying the reception signal of the second positioning satellite signal by the signal having the second local frequency.

A satellite navigation receiver and associated methods are described that can provide improved integer ambiguity resolution and more accurate positioning information. A modified BIE process may be utilized to enable the receiver to perform the integer ambiguity resolution more optimally. The output of the modified BIE process may be time-domain smoothed to provide a solution which is smoother in ambiguity space, and therefore also provide a position solution that is smoother in time. Transitions between an ambiguity-determined solution to a float solution, when necessary, may be smoothed in time. A weighting scheme may dynamically blend the ambiguity-determined solution and the float solution to leverage the advantages of both solutions, such as faster pull-in, higher accuracy, and more stable and smooth performance.

A satellite navigation receiver and associated methods are described that can provide improved integer ambiguity resolution and more accurate positioning information. A modified BIE process may be utilized to enable the receiver to perform the integer ambiguity resolution more optimally. The output of the modified BIE process may be time-domain smoothed to provide a solution which is smoother in ambiguity space, and therefore also provide a position solution that is smoother in time. Transitions between an ambiguity-determined solution to a float solution, when necessary, may be smoothed in time. A weighting scheme may dynamically blend the ambiguity-determined solution and the float solution to leverage the advantages of both solutions, such as faster pull-in, higher accuracy, and more stable and smooth performance.

A satellite corrections generation system receives reference receiver measurement information from a plurality of reference receivers at established locations. In accordance with the received reference receiver measurement information, and established locations of the reference receivers, the system determines narrow-lane navigation solutions for the plurality of reference receivers. The system also determines clusters of single-difference (SD) narrow-lane floating ambiguities, each cluster comprising pairs of SD narrow-lane floating ambiguities for respective pairs of satellites. A satellite narrow-lane bias value for each satellite of a plurality of satellites is initially determined in accordance with fractional portions of the SD narrow-lane floating ambiguities in the clusters, and then periodically updated by a Kalman filter. A set of navigation satellite corrections for each satellite, including the satellite narrow-lane bias value for each satellite, is generated and transmitted to navigation receivers for use in determining locations of the navigation receivers.

A satellite corrections generation system receives reference receiver measurement information from a plurality of reference receivers at established locations. In accordance with the received reference receiver measurement information, and established locations of the reference receivers, the system determines narrow-lane navigation solutions for the plurality of reference receivers. The system also determines clusters of single-difference (SD) narrow-lane floating ambiguities, each cluster comprising pairs of SD narrow-lane floating ambiguities for respective pairs of satellites. A satellite narrow-lane bias value for each satellite of a plurality of satellites is initially determined in accordance with fractional portions of the SD narrow-lane floating ambiguities in the clusters, and then periodically updated by a Kalman filter. A set of navigation satellite corrections for each satellite, including the satellite narrow-lane bias value for each satellite, is generated and transmitted to navigation receivers for use in determining locations of the navigation receivers.