Signal Structure Study for a Passive Ranging System using Existing Distance Measuring Equipment (DME)

The US Federal Aviation Administration (FAA) is developing alternative navigation concepts to maintain operational capacity and efficiency even in the presence of a degradation of the Global Positioning System (GPS). One concept being studied for this alternate position navigation and timing (APNT) is a ground based passive ranging system. Such a system can achieve many benefits. It has few capacity constraints, has a simpler architecture than other alternatives, can better utilize aviation spectrum, and can provide improved position navigation and timing (PNT) capabilities. One design being considered seeks to implement a passive ranging broadcast using existing distance measuring equipment (DME) ground transponders without the need for any changes. This concept, known as DME based passive ranging (DMPR), has the benefit being compatible with existing DME operations and can utilize the existing DME infrastructure. This paper develops and assesses the signal structure design to support accuracy and overall data capacity goals.