GPS Measurements Anomaly and Continuous GPS Carrier-Phase Time Transfer

Published

December 4, 2014

Author(s)

Jian Yao, Judah Levine

Abstract

The wide application of GPS carrier-phase (CP) time transfer is limited by the problem of boundary discontinuity (BD). The discontinuity has two categories. One is "day boundary discontinuity", which has been studied a lot and can be solved by a few methods. The other category of discontinuity, called "anomaly-BD", comes from GPS-measurements data anomaly. This paper focuses on the second category of discontinuity (i.e., anomaly-BD). We first demonstrate that a few minutes of GPS-measurements data anomaly are enough to lead to a discontinuity of more than 200 picoseconds in the GPS CP time transfer. To eliminate the anomaly-BD, we propose a simple, but powerful strategy, i.e., polynomial curve-fitting for the anomaly. The fitted phase measurement is typically less than 3 cm from the original phase measurement, in terms of the root mean square (RMS). And the fitted code measurement is typically less than 80 cm from the original code measurement. If we replace the anomaly with the fitted data, we can avoid the re-estimation of the phase ambiguities after the anomaly. Thus, the anomaly-BD at the anomaly should disappear. Tests show that the curve-fitting strategy works very well for up to 20 min of GPS-measurements data anomaly.

Proceedings Title

Proceedings of 2014 PTTI Meeting

Conference Dates

December 1-4, 2014

Conference Location

Boston, MA

Conference Title

2014 PTTI Meeting

Pub Type

Conferences

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Keywords

anomaly-BD, boundary discontinuity, carrier phase, curve fitting, GPS, time transfer, precise point positioning (PPP)

Citation

Yao, J. and Levine, J. (2014), GPS Measurements Anomaly and Continuous GPS Carrier-Phase Time Transfer, Proceedings of 2014 PTTI Meeting, Boston, MA, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=917574 (Accessed December 8, 2024)