Abstract: Systems and methods for the selection of antennas in aircraft navigation systems are provided. In one embodiment, a navigation receiver system for an aircraft comprises: a first aircraft antenna that receives transmitter signals from fixed-location ground transmitters and a second aircraft antenna that receives transmitter signals from the fixed-location ground transmitters, wherein the first aircraft antenna has a first gain pattern that is different from a second gain pattern of the second aircraft antenna; a switch coupled to a first receiver and the first and second aircraft antenna; and a switch controller coupled to the switch. The switch controller operates the switch to electrically couple the first receiver to either the first or second aircraft antenna based on a determination of whether the first gain pattern or the second gain pattern provides higher gain in a direction of a first fixed-location ground transmitter of the fixed-location ground transmitters.

Abstract: Systems and methods for reporting position and associated integrity during times when extrapolation is not taking place as accurately as possible. In one example, a processing device deactivates extrapolation of global positioning system (GPS) position information based on a predefined condition, receives ground speed information, and HFOM and HIL values from a global position system (GPS); calculates inflated HFOM and HIL values based on the received HFOM and HIL values and the ground speed and generates an automatic dependent surveillance-broadcast (ADS-B) OUT signal based on the calculated inflated HFOM and HIL values. A transmitter coupled to the processing device transmits the generated ADS-B OUT signal.

Abstract: In one embodiment, a method for ionospheric delay compensation is provided. The method includes determining an ionospheric delay based on a signal having propagated from the navigation satellite to a location below the ionosphere. A scale factor can be applied to the ionospheric delay, wherein the scale factor corresponds to a ratio of an ionospheric delay in the vertical direction based on an altitude of the satellite navigation system receiver. Compensation can be applied based on the ionospheric delay.

Abstract: Example embodiments disclosed herein provide for a method for detecting a fault in a receiver for a satellite navigation system. The method includes calculating a plurality of measurement residuals corresponding to a position solution and combining the plurality of measurement residuals to form a test statistic. The method also includes calculating a threshold corresponding to the test statistic, wherein calculating the threshold includes selecting the threshold to be a value from a non-central chi squared distribution of possible test statistics that corresponds to a desired probability of false alarm. The test statistic is compared to the threshold and if the test statistic is larger than the threshold, performing at least one of: outputting an alarm indicative of a fault in the position solution and discarding the position solution.

Abstract: Systems and methods for the selection of antennas in aircraft navigation systems are provided. In one embodiment, a navigation receiver system for an aircraft comprises: a first aircraft antenna that receives transmitter signals from fixed-location ground transmitters and a second aircraft antenna that receives transmitter signals from the fixed-location ground transmitters, wherein the first aircraft antenna has a first gain pattern that is different from a second gain pattern of the second aircraft antenna; a switch coupled to a first receiver and the first and second aircraft antenna; and a switch controller coupled to the switch. The switch controller operates the switch to electrically couple the first receiver to either the first or second aircraft antenna based on a determination of whether the first gain pattern or the second gain pattern provides higher gain in a direction of a first fixed-location ground transmitter of the fixed-location ground transmitters.

Abstract: In one embodiment, a method for ionospheric delay compensation is provided. The method includes determining an ionospheric delay based on a signal having propagated from the navigation satellite to a location below the ionosphere. A scale factor can be applied to the ionospheric delay, wherein the scale factor corresponds to a ratio of an ionospheric delay in the vertical direction based on an altitude of the satellite navigation system receiver. Compensation can be applied based on the ionospheric delay.

Abstract: Systems and methods for reporting position and associated integrity during times when extrapolation is not taking place as accurately as possible. In one example, a processing device deactivates extrapolation of global positioning system (GPS) position information based on a predefined condition, receives ground speed information, and HFOM and HIL values from a global position system (GPS); calculates inflated HFOM and HIL values based on the received HFOM and HIL values and the ground speed and generates an automatic dependent surveillance-broadcast (ADS-B) OUT signal based on the calculated inflated HFOM and HIL values. A transmitter coupled to the processing device transmits the generated ADS-B OUT signal.

Abstract: Example embodiments disclosed herein provide for a method for detecting a fault in a receiver for a satellite navigation system. The method includes calculating a plurality of measurement residuals corresponding to a position solution and combining the plurality of measurement residuals to form a test statistic. The method also includes calculating a threshold corresponding to the test statistic, wherein calculating the threshold includes selecting the threshold to be a value from a non-central chi squared distribution of possible test statistics that corresponds to a desired probability of false alarm. The test statistic is compared to the threshold and if the test statistic is larger than the threshold, performing at least one of: outputting an alarm indicative of a fault in the position solution and discarding the position solution.