Abstract: A navigation receiver operating in a differential navigation mode can change from one solution type to another. At each epoch, primary estimates of coordinates and the solution type are received. Each solution type has a corresponding accuracy. To improve the positioning quality when the solution type changes, smoothed estimates of coordinates are generated according to a two-branch algorithm. Two conditions are evaluated. If both conditions are satisfied, the current-epoch smoothed estimates of coordinates are set equal to the current-epoch extended estimates of coordinates calculated from the sum of the previous smoothed estimates of coordinates and coordinate increments calculated from carrier phases. If at least one of the conditions is not satisfied, updated smoothed estimates of coordinates are generated based on the sum of the current-epoch extended estimates of coordinates and a correction signal.

Abstract: A navigation receiver operating in a differential navigation mode transmits primary estimates of coordinates with an accuracy estimate that can vary during operation. To improve the positioning quality when the accuracy estimate changes, smoothed estimates of coordinates are generated according to a two-branch algorithm. The current-epoch accuracy estimate is compared to a current-epoch value of threshold accuracy. Upon determining that the current-epoch accuracy estimate is greater than or equal to the current-epoch value of threshold accuracy, the current-epoch smoothed estimates of coordinates are set equal to the current-epoch extended estimates of coordinates calculated from the sum of the previous smoothed estimates of coordinates and coordinate increments calculated from carrier phases.

Abstract: A scintillation caused by ionospheric irregularities during Global Navigation Satellite System (GNSS) measurements is detected. A first input GNSS measurement corresponding to a navigation satellite and corresponding to a first carrier frequency and a second GNSS measurement corresponding to the navigation satellite and corresponding to a second carrier frequency, in which the second carrier frequency is different from the first carrier frequency, are received. A geometry-free combination (GFC) parameter based at least in part on the first input GNSS measurement, the second input GNSS measurement, the first carrier frequency, and the second carrier frequency is calculated. The occurrence of a scintillation caused by an ionospheric irregularity is determined based at least in part on the GFC parameter. In an embodiment of the invention, the dispersion of the GFC parameter over a specified time interval is determined. A scintillation is detected if the dispersion exceeds a specified threshold value.

Abstract: Scintillations caused by ionospheric irregularities during Global Navigation Satellite System (GNSS) measurements are detected and mitigated. Detection is based at least in part on statistical properties of geometry-free combination parameters calculated from input GNSS measurements corresponding to the same navigation satellite and different carrier frequencies. Mitigation is based at least in part on ionosphere-free combination parameters calculated from input GNSS measurements corresponding to the same navigation satellite and different carrier frequencies. Depending on the number of satellites with detected scintillations, different algorithms are used to calculate values of target parameters from a set of ionosphere-free combination parameters or from a set of ionosphere-free combination parameters and the remaining input GNSS measurements.

Abstract: A scintillation caused by ionospheric irregularities during Global Navigation Satellite System (GNSS) measurements is detected. A first input GNSS measurement corresponding to a navigation satellite and corresponding to a first carrier frequency and a second GNSS measurement corresponding to the navigation satellite and corresponding to a second carrier frequency, in which the second carrier frequency is different from the first carrier frequency, are received. A geometry-free combination (GFC) parameter based at least in part on the first input GNSS measurement, the second input GNSS measurement, the first carrier frequency, and the second carrier frequency is calculated. The occurrence of a scintillation caused by an ionospheric irregularity is determined based at least in part on the GFC parameter. In an embodiment of the invention, the dispersion of the GFC parameter over a specified time interval is determined. A scintillation is detected if the dispersion exceeds a specified threshold value.

Abstract: Scintillations caused by ionospheric irregularities during Global Navigation Satellite System (GNSS) measurements are detected and mitigated. Detection is based at least in part on statistical properties of geometry-free combination parameters calculated from input GNSS measurements corresponding to the same navigation satellite and different carrier frequencies. Mitigation is based at least in part on ionosphere-free combination parameters calculated from input GNSS measurements corresponding to the same navigation satellite and different carrier frequencies. Depending on the number of satellites with detected scintillations, different algorithms are used to calculate values of target parameters from a set of ionosphere-free combination parameters or from a set of ionosphere-free combination parameters and the remaining input GNSS measurements.

Abstract: A navigation receiver operating in a differential navigation mode transmits primary estimates of coordinates with an accuracy estimate that can vary during operation. To improve the positioning quality when the accuracy estimate changes, smoothed estimates of coordinates are generated according to a two-branch algorithm. The current-epoch accuracy estimate is compared to a current-epoch value of threshold accuracy. Upon determining that the current-epoch accuracy estimate is greater than or equal to the current-epoch value of threshold accuracy, the current-epoch smoothed estimates of coordinates are set equal to the current-epoch extended estimates of coordinates calculated from the sum of the previous smoothed estimates of coordinates and coordinate increments calculated from carrier phases.

Abstract: A navigation receiver operating in a differential navigation mode can change from one solution type to another. At each epoch, primary estimates of coordinates and the solution type are received. Each solution type has a corresponding accuracy. To improve the positioning quality when the solution type changes, smoothed estimates of coordinates are generated according to a two-branch algorithm. Two conditions are evaluated. If both conditions are satisfied, the current-epoch smoothed estimates of coordinates are set equal to the current-epoch extended estimates of coordinates calculated from the sum of the previous smoothed estimates of coordinates and coordinate increments calculated from carrier phases. If at least one of the conditions is not satisfied, updated smoothed estimates of coordinates are generated based on the sum of the current-epoch extended estimates of coordinates and a correction signal.