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Accurate Navigation in Challenging Environments

A technology which utilises multi-frequency signals for a GNSS receiver to improve performance of multi-frequency receivers

Published: 19th March 2020
Accurate Navigation in Challenging Environments
Source: SpaceX,, Unsplash License.


The Global Navigation Satellite System (GNSS), which includes GPS, Galileo, GLONASS, Beidou and other regional systems, is widely used to provide precise time synchronization and highly accurate location. However, environments such as urban areas represent a challenge for GNSS as dense buildings interfere with the signal and decrease time and location accuracy. Furthermore, ionospheric scintillation can disrupt GNSS signal leading to reduced positional accuracy.

Technology Overview

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 (Figure 1).

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.

Stage of Development

Proof of concept.


  • Enables precise time synchronization and location even in highly challenging conditions
  • Works even with extremely weak signals
  • Easy to implement for any type of receiver


  • GPS receivers for drones and other UAVs
  • GNSS receivers used in challenging environments


Available for exclusive or nonexclusive licensing


IP Status
  • Patent application submitted
  • Licensing