GPS Integer Ambiguity Validation with GPS Modernization

Anning Chen, Dongfang Zheng, Arvind Ramanandan, and Jay A. Farrell

Abstract:	In GPS or GNSS positioning, the correct determination of the integer ambiguity is the key challenge to achieve centimeter level accuracy positioning. The determination of integer ambiguity can be separated into two steps: integer ambiguity estimation and integer ambiguity validation. Once the integer ambiguity is estimated, it is important to decide whether the estimate is acceptable or not. If the wrong integer estimates were accepted, they would corrupt the navigation state estimate. Therefore, integer ambiguity validation is critical. Integer validation methods can be divided into two categories. We can either validate the integers for all the satellites as a whole vector or validate each estimated integer individually. The advantage to validate each estimated integer individually is that the whole integer vector will not be rejected when few of the integers are wrong. This will be especially beneficial when there is some satellite at low elevation and thus has big measurement noise and/or multipath. However, for each integer estimate, the information can be used to perform evaluation is limited, and the measurements from multiple frequencies are critical. In this paper, we’ll focus on the methods to validate each integer separately. We will analytically introduce these methods and discuss the effect of GPS modernization to these validation methods.
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:	3156 - 3164
Cite this article:	Chen, Anning, Zheng, Dongfang, Ramanandan, Arvind, Farrell, Jay A., "GPS Integer Ambiguity Validation with GPS Modernization," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 3156-3164.
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