Published: Feb. 11, 2020


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 or fast phase fluctuations.


CU Boulder inventors Rong Yang and Yu (Jade) Morton 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 or phase fluctuation. The technique accurately estimates 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 its performance. 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 type must reach 45db-Hz. Advantages include:

  • 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

Market Application

This has a potential application for high-end GNSS receivers.

What's Next?

This technology is available for exclusive or non-exclusive licensing.