Precision-Aided Partial Ambiguity Resolution Scheme for Instantaneous RTK Positioning
The use of carrier phase data is the main driver for high-precision Global Navigation Satellite Systems (GNSS) positioning solutions, such as Real-Time Kinematic (RTK). However, carrier phase observations are ambiguous by an unknown number of cycles, and their use in RTK relies on the process of map...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-07-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/13/15/2904 |
| _version_ | 1827686417779654656 |
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| author | Juan Manuel Castro-Arvizu Daniel Medina Ralf Ziebold Jordi Vilà-Valls Eric Chaumette Pau Closas |
| author_facet | Juan Manuel Castro-Arvizu Daniel Medina Ralf Ziebold Jordi Vilà-Valls Eric Chaumette Pau Closas |
| author_sort | Juan Manuel Castro-Arvizu |
| collection | DOAJ |
| description | The use of carrier phase data is the main driver for high-precision Global Navigation Satellite Systems (GNSS) positioning solutions, such as Real-Time Kinematic (RTK). However, carrier phase observations are ambiguous by an unknown number of cycles, and their use in RTK relies on the process of mapping real-valued ambiguities to integer ones, so-called Integer Ambiguity Resolution (IAR). The main goal of IAR is to enhance the position solution by virtue of its correlation with the estimated integer ambiguities. With the deployment of new GNSS constellations and frequencies, a large number of observations is available. While this is generally positive, positioning in medium and long baselines is challenging due to the atmospheric residuals. In this context, the process of solving the complete set of ambiguities, so-called Full Ambiguity Resolution (FAR), is limiting and may lead to a decreased availability of precise positioning. Alternatively, Partial Ambiguity Resolution (PAR) relaxes the condition of estimating the complete vector of ambiguities and, instead, finds a subset of them to maximize the availability. This article reviews the state-of-the-art PAR schemes, addresses the analytical performance of a PAR estimator following a generalization of the Cramér–Rao Bound (CRB) for the RTK problem, and introduces Precision-Driven PAR (PD-PAR). The latter constitutes a new PAR scheme which employs the formal precision of the (potentially fixed) positioning solution as selection criteria for the subset of ambiguities to fix. Numerical simulations are used to showcase the performance of conventional FAR and FAR approaches, and the proposed PD-PAR against the generalized CRB associated with PAR problems. Real-data experimental analysis for a medium baseline complements the synthetic scenario. The results demonstrate that (i) the generalization for the RTK CRB constitutes a valid lower bound to assess the asymptotic behavior of PAR estimators, and (ii) the proposed PD-PAR technique outperforms existing FAR and PAR solutions as a non-recursive estimator for medium and long baselines. |
| first_indexed | 2024-03-10T09:09:54Z |
| format | Article |
| id | doaj.art-2b8e87d2972d4cedaf3a7831eb096e97 |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T09:09:54Z |
| publishDate | 2021-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-2b8e87d2972d4cedaf3a7831eb096e972023-11-22T06:05:54ZengMDPI AGRemote Sensing2072-42922021-07-011315290410.3390/rs13152904Precision-Aided Partial Ambiguity Resolution Scheme for Instantaneous RTK PositioningJuan Manuel Castro-Arvizu0Daniel Medina1Ralf Ziebold2Jordi Vilà-Valls3Eric Chaumette4Pau Closas5Institute of Communications and Navigation, German Aerospace Center (DLR), 17235 Neustrelitz, GermanyInstitute of Communications and Navigation, German Aerospace Center (DLR), 17235 Neustrelitz, GermanyInstitute of Communications and Navigation, German Aerospace Center (DLR), 17235 Neustrelitz, GermanyInstitut Supérieur de l’Aéronautique et de l’Espace (ISAE-SUPAERO), University of Toulouse, 31400 Toulouse, FranceInstitut Supérieur de l’Aéronautique et de l’Espace (ISAE-SUPAERO), University of Toulouse, 31400 Toulouse, FranceDepartment of Electrical and Computer Engineering, Northeastern University, Boston, MA 02115, USAThe use of carrier phase data is the main driver for high-precision Global Navigation Satellite Systems (GNSS) positioning solutions, such as Real-Time Kinematic (RTK). However, carrier phase observations are ambiguous by an unknown number of cycles, and their use in RTK relies on the process of mapping real-valued ambiguities to integer ones, so-called Integer Ambiguity Resolution (IAR). The main goal of IAR is to enhance the position solution by virtue of its correlation with the estimated integer ambiguities. With the deployment of new GNSS constellations and frequencies, a large number of observations is available. While this is generally positive, positioning in medium and long baselines is challenging due to the atmospheric residuals. In this context, the process of solving the complete set of ambiguities, so-called Full Ambiguity Resolution (FAR), is limiting and may lead to a decreased availability of precise positioning. Alternatively, Partial Ambiguity Resolution (PAR) relaxes the condition of estimating the complete vector of ambiguities and, instead, finds a subset of them to maximize the availability. This article reviews the state-of-the-art PAR schemes, addresses the analytical performance of a PAR estimator following a generalization of the Cramér–Rao Bound (CRB) for the RTK problem, and introduces Precision-Driven PAR (PD-PAR). The latter constitutes a new PAR scheme which employs the formal precision of the (potentially fixed) positioning solution as selection criteria for the subset of ambiguities to fix. Numerical simulations are used to showcase the performance of conventional FAR and FAR approaches, and the proposed PD-PAR against the generalized CRB associated with PAR problems. Real-data experimental analysis for a medium baseline complements the synthetic scenario. The results demonstrate that (i) the generalization for the RTK CRB constitutes a valid lower bound to assess the asymptotic behavior of PAR estimators, and (ii) the proposed PD-PAR technique outperforms existing FAR and PAR solutions as a non-recursive estimator for medium and long baselines.https://www.mdpi.com/2072-4292/13/15/2904RTKGNSSprecise positioningambiguity resolutionPARCRB |
| spellingShingle | Juan Manuel Castro-Arvizu Daniel Medina Ralf Ziebold Jordi Vilà-Valls Eric Chaumette Pau Closas Precision-Aided Partial Ambiguity Resolution Scheme for Instantaneous RTK Positioning Remote Sensing RTK GNSS precise positioning ambiguity resolution PAR CRB |
| title | Precision-Aided Partial Ambiguity Resolution Scheme for Instantaneous RTK Positioning |
| title_full | Precision-Aided Partial Ambiguity Resolution Scheme for Instantaneous RTK Positioning |
| title_fullStr | Precision-Aided Partial Ambiguity Resolution Scheme for Instantaneous RTK Positioning |
| title_full_unstemmed | Precision-Aided Partial Ambiguity Resolution Scheme for Instantaneous RTK Positioning |
| title_short | Precision-Aided Partial Ambiguity Resolution Scheme for Instantaneous RTK Positioning |
| title_sort | precision aided partial ambiguity resolution scheme for instantaneous rtk positioning |
| topic | RTK GNSS precise positioning ambiguity resolution PAR CRB |
| url | https://www.mdpi.com/2072-4292/13/15/2904 |
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