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Today's and future Global Navigation Satellite Systems (GNSS) such as GPS or Galileo are well suited for many civil and military applications and services, including the most demanding airborne segment. Accurate navigation information is provided on global scale, and through local or regional augmentation even more accurate, reliable (integrity) and continuous navigation can be ensured. For most critical periods e. g. during airborne take-off and landing, formation flight configurations, or maritime final docking scenarios, which require real-time centimeter-level positioning accuracy even in combination with most accurate attitude information, such typical GNSS configurations are limited or require extensive additional augmentation. This especially holds true for non-inertial scenarios where both users and targets are moving relative to each other, like take-off and landing operations on moving platforms.

A new "High-Precision Local Navigation System" (HP-LNS) has been developed to overcome the GNSS limitations, which provides relative and highly accurate positioning and attitude information in a local environment, and which can be fast and easily locally deployed either for temporal usage including fast self-calibration (e. g. for desert helicopter landing scenarios -brownout), or for permanent installation like on ship landing platforms.

HP-LNS consists in general of a ground, and a user segment. Based on highly accurate radar distance measurements between a set of six ground-based transmit stations and 3 user antennas, HP-LNS is able to calculate a relative position with an accuracy of below 10cm with an accurate attitude information of below 2 degrees. This most accurate navigation information is provided even in highly dynamic environments and does not require any dedicated communication link between ground-and user segment. This plain, flexible, and modular designed allows for easy integration into any manned (e. g. any size helicopter), as well as unmanned vehicle like UAVs or drones. The complete system is light-weight and designed to survive rough environmental conditions to allow for HP-LNS usage for any application, including fully automatic take-off and landing operations on moving platforms.

The paper describes the general concept and technical approach of the High-Precision Local Navigation System, its capabilities and typical use-cases, and how this new technology is in general applied to overcome GNSS limitations during most critical operation periods, still considering GNSS for en-route type navigation for the near-field approach. The paper furthermore shows various test results from UAV flight trials and further test and qualification campaigns.