Carrier-phase Position Domain Smoothing (CPDS) Algorithm and Flight Test Results for New Dual-Frequency Differential Architecture

Dean Bruckner, Frank van Graas and Trent Skidmore

Abstract:	Flight test results are presented for a single-frequency, airborne-only carrier phase position domain smoothing (CPDS) algorithm, which is a key component of a new dual-frequency differential architecture for aircraft precision approach and landing. The architecture’s first two major components—a modified dual-frequency Code Noise and Multipath (CNMP) algorithm and new composite protection level equations for horizontal, vertical and radial error—are described elsewhere by the authors. The CPDS algorithm, which is an extension of the divergence-free smoothing method, is the third and final major component. Conceptually, the CPDS algorithm harnesses the stability of continuously tracked carrier phase measurements, exploiting them to propagate the user’s position with centimeter level accuracy while keeping long-term propagated position solution error close to zero by continual updates from pseudorange measurements. Carrier phase measurements can be used as soon as they are obtained. Ionosphere-free observables are required for high accuracy, high integrity applications over all ionospheric conditions. However, uncompensated code and carrier data may be used in system development and lower-integrity applications and when severe ionospheric anomalies are not present and when the reference station is co-located with the runway threshold. Using flight test data recorded in an Ohio University King Air aircraft, performance comparison is made between the conventional 100-s LAAS ground-air smoothing technique and the CPDS air-only algorithm. A standalone implementation of the CPDS algorithm, namely one without the benefit of CNMP processing, is used here to show most clearly the benefits of this smoothing approach.
Published in:	Proceedings of the 2010 International Technical Meeting of The Institute of Navigation January 25 - 27, 2010 Catamaran Resort Hotel San Diego, CA
Pages:	293 - 305
Cite this article:	Bruckner, Dean, van Graas, Frank, Skidmore, Trent, "Carrier-phase Position Domain Smoothing (CPDS) Algorithm and Flight Test Results for New Dual-Frequency Differential Architecture," Proceedings of the 2010 International Technical Meeting of The Institute of Navigation, San Diego, CA, January 2010, pp. 293-305.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In