Navigation Systems that Take Advantage of a Next-Generation GNSS Environment

The Global Navigation Satellite System (GNSS) has recently been used widely for air navigation. The performance of onboard GNSS receivers will be improved by leveraging a next-generation GNSS environment with other GNSSs, such as the Russian GLONASS or the European Galileo systems, in addition US GPS. To utilize GNSS, there is a need to apply an augmentation system, either SBAS or GBAS, which must be upgraded for the multiple GNSS environment.

GNSSs are known to be significantly affected by the ionosphere, which is a plasma layer 300 to 400 km above ground. To mitigate its impact, we are examining how space weather information, for example the ionospheric activity forecast, can be used as a countermeasure against the active ionosphere. Ionospheric effects can also be further reduced by using dual-frequency transmission and multiple GNSSs.

It has been pointed out that GNSS is somewhat prone to jamming and spoofing attacks because it uses radio signals. For safe navigation, security measures applicable to GNSS must be developed.

In this research, we will develop dual-frequency multi-constellation (DFMC) navigation systems to take advantage of the next-generation GNSS environment and seek performance improvements by investigating local ionospheric conditions over Japan and GNSS security measures.

Verification of interoperability: GNSS other than GPS, such as European Galileo / SBAS and GBAS operated by other service providers / GNSS preciasion approaches