The Galileo High Accuracy Service (HAS) is a GNSS augmentation that provides precise satellite corrections to users worldwide for free directly through Galileo's E6 signal. The HAS service provides free PPP corrections from the Galileo constellation and the Internet, with targeted real-time 95% positioning performance of better than 20 cm horizontal and 40 cm vertical error after 5 min of convergence time globally and shorter in Europe. The HAS initial service, under validation at the time of writing, provides these capabilities with a reduced performance (based on the current Galileo stations network). Live HAS test signals broadcasted from the Galileo satellites during summer 2022 have been decoded and analyzed. Corrections include Galileo and GPS orbit, clock, and code bias corrections, with SISRE of 10.6 cm and 11.8 cm for Galileo and GPS, respectively. Code bias corrections showed good performance as well, with rms of 0.28 ns, 0.26 ns, and 0.22 ns for Galileo C1C-C5Q, C1C-C7Q, and C1C-C6C, respectively, and 0.20 ns for GPS C1C-C2L. Float PPP positioning performance results show that the combined Galileo and GPS solution can already achieve the HAS full service accuracy performance target and is close in terms of convergence time, with 95% rms of 13.1 cm and 18.6 cm horizontally and vertically, respectively, in kinematic mode, and with a 95% convergence time of 7.5 min. The latter is expected to be improved with the inclusion of satellite phase bias and local atmospheric corrections. With these early Galileo HAS test signals, this preliminary analysis indicates that the HAS full service targets are attainable. Finally, a correction latency analysis is performed, showing that even with latency of up to 60 s, positioning can remain within the targeted HAS accuracy performance.

Department of Earth and Space Science and Engineering York University Toronto ON M3J 1P3 Canada

European Union Agency for the Space Programme Prague Czech Republic

SOGEI S P A Rome Italy

Zobrazit více v PubMed

Bisnath S, Gao Y (2009) Current state of precise point positioning and future prospects and limitations. In: Sideris MG (eds) Observing our changing earth. International Association of Geodesy Symposia, vol. 133, pp 615–623. 10.1007/978-3-540-85426-5_71

Deng Y, Guo F, Ren X, Ma F, Zhang X. Estimation and analysis of multi-GNSS observable-specific code biases. GPS Solut. 2021;25(3):100. doi: 10.1007/s10291-021-01139-6. DOI

European Union (2022) Galileo High Accuracy Service signal-in-space interface control document (HAS SIS ICD), Issue 1.0. https://www.gsc-europa.eu/sites/default/files/sites/all/files/Galileo_HAS_SIS_ICD_v1.0.pdf

EUSPA (2020) Galileo high accuracy service (HAS) info note. European GNSS Agency. https://www.gsc-europa.eu/sites/default/files/sites/all/files/Galileo_HAS_Info_Note.pdf

EUSPA (2022) System | European GNSS service centre. https://www.gsc-europa.eu/galileo/system

EUSPA (2023) Galileo High Accuracy Service goes Live! | EU Agency for the Space Programme. https://www.euspa.europa.eu/newsroom/news/galileo-high-accuracy-service-now-operational

Fernandez-Hernandez I, et al. Galileo high accuracy service: initial definition and performance. GPS Solut. 2022;26(3):65. doi: 10.1007/s10291-022-01247-x. DOI

Gao Y, Li Z, McLellan JF (1997) Carrier phase based regional area differential GPS for decimeter-level positioning and navigation. In: Proceedings of the ION GPS 1997, Institute of Navigation, Kansas City, Missouri, USA, September 16–19, pp 1305–1313

Geng J, Teferle FN, Meng X, Dodson AH. Towards PPP-RTK: Ambiguity resolution in real-time precise point positioning. Adv Space Res. 2011;47(10):1664–1673. doi: 10.1016/j.asr.2010.03.030. DOI

GISCAD-OV (2022) GISCAD-OV. https://giscad-ov.eu/

Hadas T, Bosy J. IGS RTS precise orbits and clocks verification and quality degradation over time. GPS Solut. 2015;19(1):93–105. doi: 10.1007/s10291-014-0369-5. DOI

Hao M, Jiao W, Jia X, Tao Q (2020) Precise point positioning performance evaluation of QZSS centimeter level augmentation service. In: Sun J, Yang C, Xie J (eds) China satellite navigation conference (CSNC) 2020 proceedings: volume III, vol. 652. Springer, Singapore, pp 78–88. 10.1007/978-981-15-3715-8_8

Hauschild A, Montenbruck O, Steigenberger P, Martini I, Fernandez-Hernandez I. Orbit determination of sentinel-6A using the Galileo High Accuracy Service test signal. GPS Solutions. 2022;26(4):120. doi: 10.1007/s10291-022-01312-5. DOI

Jensen ABO, Cannon ME (2000) Performance of network RTK using fixed and float ambiguities. In: Proceedings of the ION NTM 2000. Institute of Navigation, Anaheim, California, USA, January 26–28, pp 797–805

Kouba J. Testing of global pressure/temperature (GPT) model and global mapping function (GMF) in GPS analyses. J Geod. 2009;83(3–4):199–208. doi: 10.1007/s00190-008-0229-6. DOI

Kouba J, Mireault Y (1998) [IGSMAIL-1943] New IGS ERP Format (version 2). https://lists.igs.org/pipermail/igsmail/1998/003315.html

Li M, Yuan Y, Wang N, Li Z, Li Y, Huo X. Estimation and analysis of Galileo differential code biases. J Geod. 2017;91(3):279–293. doi: 10.1007/s00190-016-0962-1. DOI

Liu C, Gao W, Liu T, Wang D, Yao Z, Gao Y, Nie X, Wang W, Li D, Zhang W, Wang D, Rao Y. Design and implementation of a BDS precise point positioning service. Navigation. 2020;67(4):875–891. doi: 10.1002/navi.392. DOI

Malys S, Jensen PA. Geodetic point positioning with GPS carrier beat phase data from the CASA UNO experiment. Geophys Res Lett. 1990;17(5):651–654. doi: 10.1029/GL017i005p00651. DOI

Miya M, Fujita S, Sato Y, Ota K, Hirokawa R, Takiguchi J (2016) Centimeter level augmentation service (CLAS) in Japanese quasi-zenith satellite system, its user interface, detailed design, and plan. In: Proceedings of the ION ITM 2016. Institute of Navigation, Portland, Oregon, USA, September 12–16, pp 2864–2869. 10.33012/2016.14644

Montenbruck O, Hauschild A, Steigenberger P. Differential code bias estimation using multi-GNSS observations and global ionosphere maps. Navigation. 2014;61(3):191–201. doi: 10.1002/navi.64. DOI

Montenbruck O, Steigenberger P, Hauschild A. Broadcast versus precise ephemerides: a multi-GNSS perspective. GPS Solut. 2015;19(2):321–333. doi: 10.1007/s10291-014-0390-8. DOI

Naciri N, Yi D, Bisnath S, de Blas FJ, Capua R (2022) Validation of a European High accuracy GNSS service for cadastral surveying applications. In: Proceedings of the ION GNSS+ 2022. Institute of Navigation, Denver, Colorado, USA, September 19–23, pp 381–396

Nie Z, Xu X, Wang Z, Du J. Initial assessment of BDS PPP-B2b service: precision of orbit and clock corrections, and PPP performance. Remote Sens. 2021;13(11):2500. doi: 10.3390/rs13112050. DOI

Schmid R, Dach R, Collilieux X, Jäggi A, Schmitz M, Dilssner F. Absolute IGS antenna phase center model igs08.atx: status and potential improvements. J Geod. 2016;90(4):343–364. doi: 10.1007/s00190-015-0876-3. DOI

Tao J, Liu J, Hu Z, Zhao Q, Chen G, Ju B. Initial assessment of the BDS-3 PPP-B2b RTS compared with the CNES RTS. GPS Solut. 2021;25(4):131. doi: 10.1007/s10291-021-01168-1. DOI

Teunissen PJ, Odijk D, Zhang B. PPP-RTK: results of CORS network-based PPP with integer ambiguity resolution. J Aeronaut Astronaut Aviat Ser A. 2010;42(4):223–230.

Townsend B, Lachapelle G, Fortes LP, Melgård TE, Nørbech T, Raquet J (1999) New concepts for a carrier phase based GPS positioning using a national reference station network. In: Proceedings of the ION NTM 1999. Institute of Navigation, San Diego, California, USA, January 25–27, pp 319–326

Villiger A, Schaer S, Dach R, Prange L, Sušnik A, Jäggi A. Determination of GNSS pseudo-absolute code biases and their long-term combination. J Geod. 2019;93(9):1487–1500. doi: 10.1007/s00190-019-01262-w. DOI

Wang Z, Li Z, Wang L, Wang X, Yuan H. Assessment of multiple GNSS real-time SSR products from different analysis centers. ISPRS Int J Geo Inf. 2018;7(3):85. doi: 10.3390/ijgi7030085. DOI

Xu Y, Yang Y, Li J. Performance evaluation of BDS-3 PPP-B2b precise point positioning service. GPS Solut. 2021;25(4):142. doi: 10.1007/s10291-021-01175-2. DOI

Zumberge JF, Heflin MB, Jefferson DC, Watkins MM, Webb FH. Precise point positioning for the efficient and robust analysis of GPS data from large networks (1978–2012) J Geophys Res Solid Earth. 1997;102(3):5005–5017. doi: 10.1029/96JB03860. DOI