Real-Time Multipath Estimation for Dual Frequency GPS Ionospheric Delay Measurements

Robert J. Miceli, Mark L. Psiaki, Brady W. O'Hanlon, Karen Q.Z. Chiang

Abstract:	An autoregressive moving average multipath estimator is developed using dual frequency GPS code and carrierphase ionospheric delay measurements to approximate the multipath error contribution to this measurement and to excise it. This technique provides a means of improving the real-time multipath rejection of a GNSS receiver that operates from a fixed location to perform ionospheric remote sensing. The algorithm corrects the current differential code TEC measurement by aligning it with the best multipath estimate, which is calculated from an average of the previous days’ satellite TEC measurements. The effectiveness of this technique is demonstrated by comparing the filtered and unfiltered differential code TEC measurements over the same time period. The filter ran for two extended trials of four days at mid-latitude and twentyfive days at equatorial latitude. Dual frequency L1 C/A and L2C code data was collected at 1 Hz to obtain enough measurements for high resolution multipath estimates. After running the filter over four days, the standard deviation of TEC errors was reduced by approximately 8 TECU, and after twenty-five days, the standard deviation of TEC errors was reduced by 9.5 TECU.
Published in:	Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011) September 20 - 23, 2011 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	1173 - 1178
Cite this article:	Miceli, Robert J., Psiaki, Mark L., O'Hanlon, Brady W., Chiang, Karen Q.Z., "Real-Time Multipath Estimation for Dual Frequency GPS Ionospheric Delay Measurements," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 1173-1178.
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