Applied Research Laboratories, The University of Texas (ARL:UT) has developed a differential processor titled "ProcNet" to support high-precision short-baseline surveys performed by the National Geospatial-Intelligence Agency (NGA) for the Air Force's Holloman High Speed Test Track. ProcNet eliminates many of the limitations of the legacy differential processor titled "DDBase" that is currently employed, including rigorously processing dual frequency observations and allowing the use of ANTEX antenna models. ProcNet provides improved robustness and performance as compared to DDBase, particularly when dual frequency observations are used. Initial analysis indicates short baseline precision improvements ranging from 30 to 50%, with a notable precision increase in the vertical direction. Robustness is improved by employing undifferenced GNSS observations via a rearrangement of the observation equations instead of the traditional approach using double differenced values. ProcNet is part of a new unified processing architecture developed at ARL:UT that provides both Precise Point Positioning and Differential Positioning capabilities. As a result of the new architecture, ProcNet can employ site displacement and measurement models that are traditionally used for Precise Point Positioning solutions to enable better relative solutions for long baselines.
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