FRANKFURT, Germany, December 2023 — SeRo Systems GmbH, in collaboration with the University of Kaiserslautern-Landau (RPTU), successfully completed an in-depth study for EUROCONTROL on the impacts of multipath propagation on Distance Measuring Equipment (DME) in aviation. The RPTU-led team delivered a comprehensive report that included data analysis, valuable insights, and actionable recommendations to address challenges related to multipath interference in DME operations. The results of the study were presented to stakeholders including EUROCONTROL, OEMs, and ANSPs at the EUROCAE Working Group 107 Meeting in Madrid on November 8, 2023.
DME is a radio navigation system used in aviation. Multipath propagation refers to a phenomenon where radio signals take multiple paths before reaching the receiving equipment. This can be caused by signals reflecting off of buildings, terrain, or other objects and can result in problems including signal delays, attenuation and distortion. In systems such as DME, radar or multilateration, this can lead to positioning errors, and interference which can adversely affect aviation communication, navigation, and surveillance systems.
RPTU was awarded the Data Analysis for DME Multipath Study with SeRo serving as a subcontractor, applying its in-depth domain knowledge to provide signal data processing and analytical support. Leveraging a dataset encompassing over 100 flight hours, the study’s primary objective was to identify and characterize multipath propagation effects on DME. By analyzing the various effects present in the large set of measurement data and the scenarios where multipath interference may have affected DME operations, the team aimed to pinpoint the environmental factors that contribute to DME problems. By reviewing the data, the team was able to establish a comprehensive threat model and provide practical recommendations for mitigating and preventing multipath-related challenges in DME.
Based on a data set provided by EUROCONTROL, the study focused especially on multipath at low altitude, near the final approach or initial departure phase of flight, since performance requirements are the most demanding in an airport or terminal area environment. The team provided a number of recommendations to further decrease the risk and impact of multipath-related DME ranging errors — and generally increase the integrity and accuracy of DME measurements.
This research and analysis provide another significant data point supporting the ongoing discussion about DME’s performance and reliability. The results indicated that, after dealing with a few manageable issues, DME can provide both high accuracy and integrity. Therefore, DME can serve as a basis for modern Performance-Based Navigation (PBN).This aligns with the European Union's Regulation 2018/1048 (PBN-IR), which paves the way for the full-scale transition to PBN, in all flight phases by June 2030. The report's insights into the capabilities of DME systems underscore their readiness to support PBN.
SeRo is proud to continue its relationships with RPTU and EUROCONTROL, and to have played a role in supporting this effort, which will ultimately enhance aviation safety, efficiency, and performance.