This paper details the three-way Doppler tracking demonstration conducted during the trans-lunar and early lunar orbit periods of the Lunar Reconnaissance Orbiter mission, and the NASA Goddard Space Flight Center Flight Dynamics Facility analysis of the tracking data collected. The demonstration was supported by tracking stations from the Deep Space Network, the NASA Near Earth Network, NASA facilities at White Sands, NM, and commercial tracking sites that are part of the Universal Space Network. The paper describes the planning required to coordinate tracking support for the demonstration across multiple government and commercial tracking networks, and summarizes some of the considerations and constraints that will be important for future operational use of three-way Doppler tracking data. The paper also reports on analysis performed on the Lunar Reconnaissance Orbiter tracking data, with two primary objectives: to perform a detailed assessment of the three-way Doppler data that was received, identifying systematic and random errors in the data; and to evaluate relative solution accuracy and convergence for three-way data vs. two-way data. This demonstration was motivated by the Constellation Program, which is expected to require three-way Doppler tracking data to meet lunar mission navigation requirements. The analysis does not show significant improvements in LRO navigation solutions through the inclusion of three-way Doppler data, in part due to the limited amount of data collected and lack of the small random accelerations associated with pressurized/manned spaceflight operations; however, the three-way tracking demonstration was successful in providing important experience and lessons learned that will be applicable to Constellation and other future missions.
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