Abstract: A method for determining an electron density in a portion of an ionosphere includes: receiving, at a satellite in orbit, a signal transmitted from a ground-based transmitter through a portion of the ionosphere between the satellite and the ground transmitter; receiving, at the satellite, a reflection of the signal from a portion of the ionosphere above the satellite; and determining, based on the signal received at the satellite transmitted from the ground-based transmitter through the portion of the ionosphere between the satellite and the ground-based transmitter and the reflection of the signal received from the portion of the ionosphere above the satellite, an electron density of the portion of the ionosphere above the satellite.

Abstract: An exemplary method for determining a total electron content of a portion of the ionosphere includes: transmitting from a satellite in orbit, a first signal at a first frequency and a second signal at a second frequency different from the first frequency toward a reflective surface through the portion of the ionosphere, wherein the first and second frequencies are in the very high frequency (VHF) range; receiving at the satellite, a reflection of the first signal and a reflection the second signal; determining a first delay of the reflection of the first signal and a second delay of the reflection of the second signal; and determining at least a first total electron content of the portion of the ionosphere based the first delay and the second delay.

Abstract: Various embodiments of the present technology generally relate to localization of one or more radio frequency interference (RFI) emitters. More specifically some embodiments relate to localization of RFI emitters that interfere with Global Navigation Satellite System (GNSS) receivers by integrating the location estimates of two or more localization techniques. Various embodiments may be used to more accurately estimate an interference source (e.g., an RFI emitter's location) than each localization technique separately.

Abstract: Various embodiments of the present technology generally relate to localization of one or more radio frequency interference (RFI) emitters. More specifically some embodiments relate to localization of RFI emitters that interfere with Global Navigation Satellite System (GNSS) receivers by integrating the location estimates of two or more localization techniques. Various embodiments may be used to more accurately estimate an interference source (e.g., an RFI emitter's location) than each localization technique separately.