Containing a Difficult Target: Techniques for Mitigating DME Multipath to Alternative Position Navigation and Timing (APNT)

Distance measuring equipment (DME)/Tactical Air Navigation (TACAN) has been serving aviation for approximately 60 years. It has been a primary navigation aid in the national airspace (NAS) for much of that time with its basic operations little changed since its inception. However, future airspace will demand greater navigation performance to support higher traffic levels and more efficient operations. While Global Navigation Satellite Systems (GNSS) will be the primary source of this capability, DME can have a vital role in the future navigation infrastructure. The Federal Aviation Administration (FAA) Alternative Position Navigation and Timing (APNT) program is examining the use of DME to provide accurate two-way and passive ranging. APNT is examining whether DME has the capability to allow for continued operations of the NAS with minimal economic impact. For DME to support this capability, it must have better performance in several areas: accuracy, integrity, capacity and coverage.