Mitigating BeiDou Satellite-Induced Code Bias: Taking into Account the Stochastic Model of Corrections
The BeiDou satellite-induced code biases have been confirmed to be orbit type-, frequency-, and elevation-dependent. Such code-phase divergences (code bias variations) severely affect absolute precise applications which use code measurements. To reduce their adverse effects, an improved correction m...
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MDPI AG
2016-06-01
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| Series: | Sensors |
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| Online Access: | http://www.mdpi.com/1424-8220/16/6/909 |
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| author | Fei Guo Xin Li Wanke Liu |
| author_facet | Fei Guo Xin Li Wanke Liu |
| author_sort | Fei Guo |
| collection | DOAJ |
| description | The BeiDou satellite-induced code biases have been confirmed to be orbit type-, frequency-, and elevation-dependent. Such code-phase divergences (code bias variations) severely affect absolute precise applications which use code measurements. To reduce their adverse effects, an improved correction model is proposed in this paper. Different from the model proposed by Wanninger and Beer (2015), more datasets (a time span of almost two years) were used to produce the correction values. More importantly, the stochastic information, i.e., the precision indexes, were given together with correction values in the improved model. However, only correction values were given while the precision indexes were completely missing in the traditional model. With the improved correction model, users may have a better understanding of their corrections, especially the uncertainty of corrections. Thus, it is helpful for refining the stochastic model of code observations. Validation tests in precise point positioning (PPP) reveal that a proper stochastic model is critical. The actual precision of the corrected code observations can be reflected in a more objective manner if the stochastic model of the corrections is taken into account. As a consequence, PPP solutions with the improved model outperforms the traditional one in terms of positioning accuracy, as well as convergence speed. In addition, the Melbourne-Wübbena (MW) combination which serves for ambiguity fixing were verified as well. The uncorrected MW values show strong systematic variations with an amplitude of half a wide-lane cycle, which prevents precise ambiguity determination and successful ambiguity resolution. After application of the code bias correction models, the systematic variations can be greatly removed, and the resulting wide lane ambiguities are more likely to be fixed. Moreover, the code residuals show more reasonable distributions after code bias corrections with either the traditional or the improved model. |
| first_indexed | 2024-04-11T12:45:44Z |
| format | Article |
| id | doaj.art-e506f3cc731e46f6a9a014c238c5ff76 |
| institution | Directory Open Access Journal |
| issn | 1424-8220 |
| language | English |
| last_indexed | 2024-04-11T12:45:44Z |
| publishDate | 2016-06-01 |
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| series | Sensors |
| spelling | doaj.art-e506f3cc731e46f6a9a014c238c5ff762022-12-22T04:23:21ZengMDPI AGSensors1424-82202016-06-0116690910.3390/s16060909s16060909Mitigating BeiDou Satellite-Induced Code Bias: Taking into Account the Stochastic Model of CorrectionsFei Guo0Xin Li1Wanke Liu2School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, ChinaSchool of Geodesy and Geomatics, Wuhan University, Wuhan 430079, ChinaSchool of Geodesy and Geomatics, Wuhan University, Wuhan 430079, ChinaThe BeiDou satellite-induced code biases have been confirmed to be orbit type-, frequency-, and elevation-dependent. Such code-phase divergences (code bias variations) severely affect absolute precise applications which use code measurements. To reduce their adverse effects, an improved correction model is proposed in this paper. Different from the model proposed by Wanninger and Beer (2015), more datasets (a time span of almost two years) were used to produce the correction values. More importantly, the stochastic information, i.e., the precision indexes, were given together with correction values in the improved model. However, only correction values were given while the precision indexes were completely missing in the traditional model. With the improved correction model, users may have a better understanding of their corrections, especially the uncertainty of corrections. Thus, it is helpful for refining the stochastic model of code observations. Validation tests in precise point positioning (PPP) reveal that a proper stochastic model is critical. The actual precision of the corrected code observations can be reflected in a more objective manner if the stochastic model of the corrections is taken into account. As a consequence, PPP solutions with the improved model outperforms the traditional one in terms of positioning accuracy, as well as convergence speed. In addition, the Melbourne-Wübbena (MW) combination which serves for ambiguity fixing were verified as well. The uncorrected MW values show strong systematic variations with an amplitude of half a wide-lane cycle, which prevents precise ambiguity determination and successful ambiguity resolution. After application of the code bias correction models, the systematic variations can be greatly removed, and the resulting wide lane ambiguities are more likely to be fixed. Moreover, the code residuals show more reasonable distributions after code bias corrections with either the traditional or the improved model.http://www.mdpi.com/1424-8220/16/6/909BeiDoucode bias variationcode-phase divergencestochastic modelprecise point positioning |
| spellingShingle | Fei Guo Xin Li Wanke Liu Mitigating BeiDou Satellite-Induced Code Bias: Taking into Account the Stochastic Model of Corrections Sensors BeiDou code bias variation code-phase divergence stochastic model precise point positioning |
| title | Mitigating BeiDou Satellite-Induced Code Bias: Taking into Account the Stochastic Model of Corrections |
| title_full | Mitigating BeiDou Satellite-Induced Code Bias: Taking into Account the Stochastic Model of Corrections |
| title_fullStr | Mitigating BeiDou Satellite-Induced Code Bias: Taking into Account the Stochastic Model of Corrections |
| title_full_unstemmed | Mitigating BeiDou Satellite-Induced Code Bias: Taking into Account the Stochastic Model of Corrections |
| title_short | Mitigating BeiDou Satellite-Induced Code Bias: Taking into Account the Stochastic Model of Corrections |
| title_sort | mitigating beidou satellite induced code bias taking into account the stochastic model of corrections |
| topic | BeiDou code bias variation code-phase divergence stochastic model precise point positioning |
| url | http://www.mdpi.com/1424-8220/16/6/909 |
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