A method is for detecting loss-of-lock of a GNSS (Global Navigation Satellite System) signal tracking loop based on frequency compensation, comprising the following steps of: performing multi-channel frequency compensation on I-channel and Q-channel signals after down-conversion, pseudo-code stripping and integration clearing; then, performing coherent integration and non-coherent integration for a fixed time, and taking a maximum value of non-coherent integration results as a signal value; performing parabolic interpolation frequency identification, and taking an average value of the non-coherent integration results with the frequency differences of +/−50 Hz and +/−100 Hz as a noise value; and finally, calculating a ratio of the signal value to the noise value, and performing loss-of-lock detection with the ratio as a detection volume.

A method is for detecting loss-of-lock of a GNSS (Global Navigation Satellite System) signal tracking loop based on frequency compensation, comprising the following steps of: performing multi-channel frequency compensation on I-channel and Q-channel signals after down-conversion, pseudo-code stripping and integration clearing; then, performing coherent integration and non-coherent integration for a fixed time, and taking a maximum value of non-coherent integration results as a signal value; performing parabolic interpolation frequency identification, and taking an average value of the non-coherent integration results with the frequency differences of +/−50 Hz and +/−100 Hz as a noise value; and finally, calculating a ratio of the signal value to the noise value, and performing loss-of-lock detection with the ratio as a detection volume.

A navigation satellite receiver system is disclosed. The system includes a host receiver. The host receiver includes a user interface, a module connector, and a controller coupled to the user interface and the module connector. The system further includes a receiver module operably coupled to the receiver module. The receiver module includes an antenna configured to receive one or more satellite navigation signal. The receiver module further includes an interface receiver card operably coupled to the module antenna. The interface receiver card is configured to process the one or more navigation signals. The receiver module further includes a host connector communicatively coupled to the interface receiver card and is configured to couple to the module connector. The module includes a housing configured to receive and protect the interface receiver card, the antenna, and the host connector.

A navigation satellite receiver system is disclosed. The system includes a host receiver. The host receiver includes a user interface, a module connector, and a controller coupled to the user interface and the module connector. The system further includes a receiver module operably coupled to the receiver module. The receiver module includes an antenna configured to receive one or more satellite navigation signal. The receiver module further includes an interface receiver card operably coupled to the module antenna. The interface receiver card is configured to process the one or more navigation signals. The receiver module further includes a host connector communicatively coupled to the interface receiver card and is configured to couple to the module connector. The module includes a housing configured to receive and protect the interface receiver card, the antenna, and the host connector.

According to one or more embodiments herein, interferometry-based satellite location accuracy is provided. In one embodiment, a method comprises: determining, generally at a substantially given time, a reference satellite having a known accurate location within angular proximity of a communication satellite having a known general location; determining an accurate angular position of the communication satellite with relation to the reference satellite from the perspective of at least one ground station antenna of a known accurate location; determining an additional location reference measurement of the communication satellite; determining an accurate location of the communication satellite at the substantially given time based at least in part on the accurate angular position of the communication satellite with relation to the reference satellite from the perspective of the at least one ground station antenna and the additional location reference measurement of the communication satellite; and utilizing the accurate location of the communication satellite.

According to one or more embodiments herein, interferometry-based satellite location accuracy is provided. In one embodiment, a method comprises: determining, generally at a substantially given time, a reference satellite having a known accurate location within angular proximity of a communication satellite having a known general location; determining an accurate angular position of the communication satellite with relation to the reference satellite from the perspective of at least one ground station antenna of a known accurate location; determining an additional location reference measurement of the communication satellite; determining an accurate location of the communication satellite at the substantially given time based at least in part on the accurate angular position of the communication satellite with relation to the reference satellite from the perspective of the at least one ground station antenna and the additional location reference measurement of the communication satellite; and utilizing the accurate location of the communication satellite.

A method of processing signal paths includes receiving an estimated location for a GNSS receiver in an environment. The method also includes generating a plurality of candidate positions about the estimated location where each candidate position corresponds to a possible actual location of the GNSS receiver. The method further includes, for each available satellite at each candidate position, modeling a plurality of candidate signal paths by ray-launching a raster map of geographical data. Here, the plurality of candidate signal paths includes one or more reflected signal paths. At each candidate position, the method also includes comparing, the plurality of candidate signal paths modeled for each available satellite at the respective candidate position to measured GNSS signal data from the GNSS receiver and generating a likelihood that the respective candidate position includes the actual location of the GNSS receiver based on the comparison.

A method of processing signal paths includes receiving an estimated location for a GNSS receiver in an environment. The method also includes generating a plurality of candidate positions about the estimated location where each candidate position corresponds to a possible actual location of the GNSS receiver. The method further includes, for each available satellite at each candidate position, modeling a plurality of candidate signal paths by ray-launching a raster map of geographical data. Here, the plurality of candidate signal paths includes one or more reflected signal paths. At each candidate position, the method also includes comparing, the plurality of candidate signal paths modeled for each available satellite at the respective candidate position to measured GNSS signal data from the GNSS receiver and generating a likelihood that the respective candidate position includes the actual location of the GNSS receiver based on the comparison.

A Weil code generator and a method of generating Weil codes with a Weil code length (N) are provided. The Weil code generator includes a plurality of parallel channels (10), a multi-channel read arbiter (20), and two parallel Legendre ROMs (30), which are connected in series. A channel of the plurality of channels stores a current Weil code to demodulate signals from a satellite. The multi-channel read arbiter (20) may determine a win channel from the plurality of channels. The two Legendre ROMs (30) respectively store a first and a second Legendre sequences (LS1, LS2) each having a Legendre sequence length (2N) being double the Weil code length (N). The Weil code generator may generate Weil codes efficiently.

A Weil code generator and a method of generating Weil codes with a Weil code length (N) are provided. The Weil code generator includes a plurality of parallel channels (10), a multi-channel read arbiter (20), and two parallel Legendre ROMs (30), which are connected in series. A channel of the plurality of channels stores a current Weil code to demodulate signals from a satellite. The multi-channel read arbiter (20) may determine a win channel from the plurality of channels. The two Legendre ROMs (30) respectively store a first and a second Legendre sequences (LS1, LS2) each having a Legendre sequence length (2N) being double the Weil code length (N). The Weil code generator may generate Weil codes efficiently.