Usage of Geometric Altitude for Radar Plot Position Improvements

Abstract

In ATC Tracking applications, the barometric altitude of measured aircraft is predominantly used as a substitute for the geometric altitude in slant range correction of Radar target reports, introducing position errors. With ADS-B being frequently available and of increasing quality, a reliable source for geometric altitude information has become available, allowing for improvements in Radar plot position accuracy. In the presented work, the availability, quality, modeling and reconstruction of such geometric altitude information are reviewed and discussed in relation to current solutions based on barometric altitude. For a single Radar, options for accuracy improvement are described and assessed in comparison to reference data, i.e., ATC Tracker output and real-live meteorological measurements. The application of the discussed ADS-B-based methods can be used to improve Radar plot position accuracy, contributing to aircraft surveillance cost-efficiency and safety.

Keywords

• ADS-B
• radar
• slant range
• geometric altitude
• barometric altitude
• QNH