Published: Feb. 23, 2022



Global Navigation Satellite System (GNSS), which includes GPS, Galileo, GLONASS, Beidou and other regional systems, has been widely used to provide precise time synchronization and highly accurate location. There is a growing need to continue operating the GNSS receivers under increasingly challenging and stressful conditions, such as in urban areas with multipath interferences or in the presence of ionosphere and/or troposphere scintillations on ground-based or satellite-based platforms, where the signal experiences deep amplitude fading and/or fast phase fluctuations.Space



The inventors have developed a technology that uses the multi-frequency signals for a GNSS receiver (such as GPS) to improve performance of multi-frequency receivers in environments where signals on one or more frequency band experiences amplitude fading and/or phase fluctuation. The technique accurately estimates ranging parameters of satellite navigation signals that are experiencing fading using measurements obtained from the less compromised frequency bands. These parameters are used to construct local reference signals necessary for the receiver to maintain lock on the fading signals, drastically improving the receiver robustness and accuracy. The system works even if all three signals are extremely weak, but reach at least 15db-Hz, or two signals reach 10db-Hz, but the third signal at nominal level.

Further Details:

Yang, Rong, Morton, Yu, “An Adaptive Inter-frequency Aiding Carrier Tracking Algorithm for the Mountain-top GPS Radio Occultation Signal,” Proceedings of the 2018 International Technical Meeting of The Institute of Navigation, Reston, Virginia, January 2018, pp. 412-419.


  • Works even with extremely weak signals
  • Easy to implement for any type of receiver
  • Improves the performance of high-end receivers
  • Enables precise time synchronization and location even in highly challenging conditions

Stage of Development

Proof of Concept.

What's Next?

Available for exclusive or non-exlcusive licensing


Nicole Forsberg: