Title: Using Interpolation and Extrapolation Techniques to Yield High Data Rates and Ionosphere Delay Estimates from Continuously Operating GPS Networks
Author(s): Gerald L. Mader and Michael L. Morrison
Published in: Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002)
September 24 - 27, 2002
Oregon Convention Center
Portland, OR
Pages: 2342 - 2348
Cite this article: Mader, Gerald L., Morrison, Michael L., "Using Interpolation and Extrapolation Techniques to Yield High Data Rates and Ionosphere Delay Estimates from Continuously Operating GPS Networks," Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002), Portland, OR, September 2002, pp. 2342-2348.
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Abstract: Kinematic GPS techniques are used routinely to calculate the trajectories of moving platforms. In order to track this motion as closely as possible, data rates of 1 Hz or greater are often used. Differential carrier phase solutions require matching data from a reference station located at a known position. These reference stations have usually been deployed by the users on an as-needed basis. However, it is difficult to contemplate permanent and continuously operating GPS networks providing these high-rate data in the future on a routine basis. Such a large volume of data can pose severe bandwidth problems in collecting and then communicating these data to the user, in addition to the need to possibly archive these data. A solution to these problems is to produce high-rate phase and range data (e.g. at a 1 second rate) at the reference stations by interpolating or extrapolating lower-rate data (e.g. 5, 10, 15, … sec rate). Interpolation techniques would be used for post-processing while extrapolation, allowing for data transmission latencies, would be suitable for real time processing. These techniques are evaluated by producing low-data rate, reference station RINEX files (e.g. 5, 15, 30 sec) from an original high-rate (1 sec) data set. A comparison of kinematic solutions from interpolated and extrapolated data show negligible to acceptable differences from solutions using original high-rate data. Network station spacing should be determined by the distance-dependent effects within the network. The primary distance-dependent effect is delay due to propagation through the ionosphere. Ionosphere delays are important for integer ambiguity resolution and can be estimated within the network from known delays on network baselines. This investigation compares such predictions from small local networks of various sizes to the actual ionosphere delays on a test baseline. Preliminary results indicate that acceptably accurate ionosphere delays may be predicted from networks with station spacings ranging up to 150-200 km.