Integrity Monitoring of PPP-RTK Positioning; Part I: GNSS-Based IM Procedure
Nowadays, integrity monitoring (IM) is required for diverse safety-related applications using intelligent transport systems (ITS). To ensure high availability for road transport users for in-lane positioning, a sub-meter horizontal protection level (HPL) is expected, which normally requires a much h...
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| Format: | Article |
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MDPI AG
2021-12-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/14/1/44 |
| _version_ | 1797497760421773312 |
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| author | Kan Wang Ahmed El-Mowafy Weijin Qin Xuhai Yang |
| author_facet | Kan Wang Ahmed El-Mowafy Weijin Qin Xuhai Yang |
| author_sort | Kan Wang |
| collection | DOAJ |
| description | Nowadays, integrity monitoring (IM) is required for diverse safety-related applications using intelligent transport systems (ITS). To ensure high availability for road transport users for in-lane positioning, a sub-meter horizontal protection level (HPL) is expected, which normally requires a much higher horizontal positioning precision of, e.g., a few centimeters. Precise point positioning-real-time kinematic (PPP-RTK) is a positioning method that could achieve high accuracy without long convergence time and strong dependency on nearby infrastructure. As the first part of a series of papers, this contribution proposes an IM strategy for multi-constellation PPP-RTK positioning based on global navigation satellite system (GNSS) signals. It analytically studies the form of the variance-covariance (V-C) matrix of ionosphere interpolation errors for both accuracy and integrity purposes, which considers the processing noise, the ionosphere activities and the network scale. In addition, this contribution analyzes the impacts of diverse factors on the size and convergence of the HPLs, including the user multipath environment, the ionosphere activity, the network scale and the horizontal probability of misleading information (PMI). It is found that the user multipath environment generally has the largest influence on the size of the converged HPLs, while the ionosphere interpolation and the multipath environments have joint impacts on the convergence of the HPL. Making use of 1 Hz data of Global Positioning System (GPS)/Galileo/Beidou Navigation Satellite System (BDS) signals on L1 and L5 frequencies, for small- to mid-scaled networks, under nominal multipath environments and for a horizontal PMI down to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup></mrow></semantics></math></inline-formula>, the ambiguity-float HPLs can converge to 1.5 m within or around 50 epochs under quiet to medium ionosphere activities. Under nominal multipath conditions for small- to mid-scaled networks, with the partial ambiguity resolution enabled, the HPLs can converge to 0.3 m within 10 epochs even under active ionosphere activities. |
| first_indexed | 2024-03-10T03:23:52Z |
| format | Article |
| id | doaj.art-38c33bfc7f60402e9b97f8dd44c3844d |
| institution | Directory Open Access Journal |
| issn | 2072-4292 |
| language | English |
| last_indexed | 2024-03-10T03:23:52Z |
| publishDate | 2021-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Remote Sensing |
| spelling | doaj.art-38c33bfc7f60402e9b97f8dd44c3844d2023-11-23T12:12:15ZengMDPI AGRemote Sensing2072-42922021-12-011414410.3390/rs14010044Integrity Monitoring of PPP-RTK Positioning; Part I: GNSS-Based IM ProcedureKan Wang0Ahmed El-Mowafy1Weijin Qin2Xuhai Yang3National Time Service Center, Chinese Academy of Sciences, Xi’an 710600, ChinaSchool of Earth and Planetary Sciences, Curtin University, Perth, WA 6845, AustraliaNational Time Service Center, Chinese Academy of Sciences, Xi’an 710600, ChinaNational Time Service Center, Chinese Academy of Sciences, Xi’an 710600, ChinaNowadays, integrity monitoring (IM) is required for diverse safety-related applications using intelligent transport systems (ITS). To ensure high availability for road transport users for in-lane positioning, a sub-meter horizontal protection level (HPL) is expected, which normally requires a much higher horizontal positioning precision of, e.g., a few centimeters. Precise point positioning-real-time kinematic (PPP-RTK) is a positioning method that could achieve high accuracy without long convergence time and strong dependency on nearby infrastructure. As the first part of a series of papers, this contribution proposes an IM strategy for multi-constellation PPP-RTK positioning based on global navigation satellite system (GNSS) signals. It analytically studies the form of the variance-covariance (V-C) matrix of ionosphere interpolation errors for both accuracy and integrity purposes, which considers the processing noise, the ionosphere activities and the network scale. In addition, this contribution analyzes the impacts of diverse factors on the size and convergence of the HPLs, including the user multipath environment, the ionosphere activity, the network scale and the horizontal probability of misleading information (PMI). It is found that the user multipath environment generally has the largest influence on the size of the converged HPLs, while the ionosphere interpolation and the multipath environments have joint impacts on the convergence of the HPL. Making use of 1 Hz data of Global Positioning System (GPS)/Galileo/Beidou Navigation Satellite System (BDS) signals on L1 and L5 frequencies, for small- to mid-scaled networks, under nominal multipath environments and for a horizontal PMI down to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2</mn><mo>×</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>6</mn></mrow></msup></mrow></semantics></math></inline-formula>, the ambiguity-float HPLs can converge to 1.5 m within or around 50 epochs under quiet to medium ionosphere activities. Under nominal multipath conditions for small- to mid-scaled networks, with the partial ambiguity resolution enabled, the HPLs can converge to 0.3 m within 10 epochs even under active ionosphere activities.https://www.mdpi.com/2072-4292/14/1/44integrity monitoringPPP-RTKionosphereGNSSprotection level |
| spellingShingle | Kan Wang Ahmed El-Mowafy Weijin Qin Xuhai Yang Integrity Monitoring of PPP-RTK Positioning; Part I: GNSS-Based IM Procedure Remote Sensing integrity monitoring PPP-RTK ionosphere GNSS protection level |
| title | Integrity Monitoring of PPP-RTK Positioning; Part I: GNSS-Based IM Procedure |
| title_full | Integrity Monitoring of PPP-RTK Positioning; Part I: GNSS-Based IM Procedure |
| title_fullStr | Integrity Monitoring of PPP-RTK Positioning; Part I: GNSS-Based IM Procedure |
| title_full_unstemmed | Integrity Monitoring of PPP-RTK Positioning; Part I: GNSS-Based IM Procedure |
| title_short | Integrity Monitoring of PPP-RTK Positioning; Part I: GNSS-Based IM Procedure |
| title_sort | integrity monitoring of ppp rtk positioning part i gnss based im procedure |
| topic | integrity monitoring PPP-RTK ionosphere GNSS protection level |
| url | https://www.mdpi.com/2072-4292/14/1/44 |
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