Mayank, F. S. Prol, V. Lundén, et al., “LEO-PNT feasibility aspects: Satellite navigation payload size, weight, and power analysis,” IEEE Access, vol. 13, pp. 110 069–110 089, 2025. DOI: 10.1109/ACCESS.2 025.3583080.
M. Hui, S. Zhai, D. Wang, et al., “A review of LEO-satellite communication payloads for integrated communication, navigation, and remote sensing: Opportunities, challenges, future directions,” IEEE Internet of Things Journal, vol. 12, no. 12, pp. 18 954–18 992, Jun. 2025. DOI: 10.1109/JIOT.20 25.3553942.
W. Stock, R. T. Schwarz, C. A. Hofmann, and A. Knopp, “Survey on opportunistic PNT with signals from LEO communication satellites,” IEEE Communications Surveys & Tutorials, vol. 27, no. 1, pp. 77–107, Feb. 2025. DOI: 10.1109/COMST.2024.3 406990.
K. Çelikbilek, E. Simona Lohan, and J. Praks, “Optimization of a LEO-PNT constellation: Design considerations and open challenges,” International Journal of Satellite Communications and Networking, vol. 43, no. 4, pp. 272–292, 2025. DOI: 10.1002/sat.1 555.
M. Shafi, A. F. Molisch, P. J. Smith, et al., “5g: A tutorial overview of standards, trials, challenges, deployment, and practice,” IEEE Journal on Selected Areas in Communications, vol. 35, no. 6, pp. 1201–1221, Jun. 2017. DOI: 10.1109/JSAC.2017 .2692307.
X. Lin, “The bridge toward 6g: 5g-advanced evolution in 3gpp release i9,” IEEE Communications Standards Magazine, vol. 9, no. 1, pp. 28–35, Mar. 2025. DOI: 10.1109/MCOMSTD.0001.2300063.
M. El Jaafari, N. Chuberre, S. Anjuere, and L. Combelles, “Introduction to the 3gpp-defined NTN standard: A comprehensive view on the 3gpp work on NTN,” International Journal of Satellite Communications and Networking, vol. 41, no. 3, pp. 220–238, 2023. DOI: 10.1002/sat.1471.
I. Rahman, S. M. Razavi, O. Liberg, et al., “5g evolution toward 5g advanced: An overview of 3gpp releases 17 and 18,” Ericsson Technology Review, vol. 2021, no. 14, pp. 2–12, Oct. 2021. DOI: 10.23 919/ETR.2021.9904665.
H. K. Dureppagari, C. Saha, H. S. Dhillon, and R. M. Buehrer, NTN-based 6g localization: Vision, role of LEOs, and open problems, Sep. 7, 2023. DOI: 10.485 50/arXiv.2305.12259.
“IMT towards 2030 and beyond (IMT-2030),” ITU. (), [Online]. Available: https://www.itu.int:443/en/ITU-R/study-groups/rsg5/rwp5d/imt-2030/pages/def ault.aspx (visited on 05/08/2025).
X. Lin, “An overview of 5g advanced evolution in 3gpp release 18,” IEEE Communications Standards Magazine, vol. 6, no. 3, pp. 77–83, Sep. 2022. DOI: 10.1109/MCOMSTD.0001.2200001.
3GPP, TR 38.882 “study on requirements and use cases for network verified UE location for non-terrestrial-networks (NTN) in NR,”, version 18.0.0, Jun. 2022. [Online]. Available: https://www.3gpp.org/ftp/Specs/archive/38_series/38.882/38882-i00.zip (visited on 08/27/2025).
ETSI, Base station (BS) radio transmission and reception (3gpp TS 38.104 version 18.5.0 release 18), 2024. [Online]. Available: https://www.etsi.org/deliver/etsi_ts/138100_138199/138104/16.04.00_60/ts_138 104v160400p.pdf.
S. Kang, M. Mezzavilla, S. Rangan, et al., “Cellular wireless networks in the upper mid-band,” IEEE Open Journal of the Communications Society, vol. 5, pp. 2058–2075, 2024. DOI: 10.1109/OJCOMS.2024.3 373368.
N.-N. Dao, N. H. Tu, T.-D. Hoang, et al., “A review on new technologies in 3gpp standards for 5g access and beyond,” Computer Networks, vol. 245, p. 110 370, May 1, 2024. DOI: 10.1016/j.comnet.2024.110370.
3GPP, TS 38.305, “NG radio access network (NG-RAN); stage 2 functional specification of user equipment (UE) positioning in NG-RAN,”, version 17.0.0, 2022. [Online]. Available: https://www.etsi.org/deliver/etsi_ts/138300_138399/13830 5/17.00.00_60/ts_138305v170000p.pdf (visited on 08/27/2025).
A. Gonzalez-Garrido, J. Querol, H. Wymeersch, and S. Chatzinotas, “Interference analysis and modeling of positioning reference signals in 5g NTN,” IEEE Open Journal of the Communications Society, vol. 5, pp. 7567–7581, 2024. DOI: 10.1109/OJCOMS.2024.3 503692.
R. M. Ferre and E. S. Lohan, “Comparison of MEO, LEO, and terrestrial IoT configurations in terms of GDOP and achievable positioning accuracies,” IEEE Journal of Radio Frequency Identification, vol. 5, no. 3, pp. 287–299, Sep. 2021. DOI: 10.1109/JRFID.2 021.3079475.
S. Emara, “Positioning in non-terrestrial networks,” Ph.D. dissertation, Lund University, 2021.
I. Lapin, G. Serafini, A. M. Marziani, et al., “Code phase estimation with live 5g NR-NTN ka-band signal from LEO satellite using STARE,” in 2024 11th Workshop on Satellite Navigation Technology (NAVITEC), Dec. 2024, pp. 1–5. DOI: 10.1109/NA VITEC63575.2024.10843556.
M. Brambilla, M. Alghisi, B. Camajori Tedeschini, et al., “Integration of 5g and GNSS technologies for enhanced positioning: An experimental study,” IEEE Open Journal of the Communications Society, vol. 5, pp. 7197–7215, 2024. DOI: 10.1109/OJCOMS.2024.3 487270.
B. Camajori Tedeschini, M. Brambilla, L. Italiano, et al., “A feasibility study of 5g positioning with current cellular network deployment,” Scientific Reports, vol. 13, no. 1, p. 15 281, Sep. 15, 2023. DOI: 10.1 038/s41598-023-42426-1.
K. Shamaei and Z. M. Kassas, “Receiver design and time of arrival estimation for opportunistic localization with 5g signals,” IEEE Transactions on Wireless Communications, vol. 20, no. 7, pp. 4716–4731, Jul. 2021. DOI: 10.1109/TWC.2021.3061985.
F. Mooseli, S. Hayek, S. Kozhaya, and Z. M. Kassas, “Opportunistic navigation exploiting always-on and on-demand 5g downlink signals on a ground vehicle,” in 2024 IEEE 100th Vehicular Technology Conference (VTC2024-Fall), Oct. 2024, pp. 1–5. DOI: 10 . 1109 /VTC2024-Fall63153.2024.10757621.
Z. Kassas and K. Shamaei, “Systems and methods for opportunistic time of arrival estimation for opportunistic localization with 5g signals,” U.S. Patent 20230171142A1, Jun. 1, 2023.
A. Abdallah, J. Khalife, and Z. M. Kassas, “Exploiting on-demand 5g downlink signals for opportunistic navigation,” IEEE Signal Processing Letters, vol. 30, pp. 389–393, 2023. DOI: 10.1109/LSP.2023.3234496.
M. Neinavaie, J. Khalife, and Z. M. Kassas, “Cognitive opportunistic navigation in private networks with 5g signals and beyond,” IEEE Journal of Selected Topics in Signal Processing, vol. 16, no. 1, pp. 129–143, Jan. 2022. DOI: 10.1109/JSTSP.2 021.3119929.
E. D. Kaplan and C. Hegarty, Understanding GPS/GNSS: Principles and Applications, Third Edition. Artech House, 2017, ISBN: 978-1-63081-442-7.
W. Lewandowski, J. Azoubib, and W. Klepczynski, “GPS: Primary tool for time transfer,” Proceedings of the IEEE, vol. 87, no. 1, pp. 163–172, Jan. 1999. DOI: 10.1109/5.736348.
K. Wang and A. El-Mowafy, “LEO satellite clock analysis and prediction for positioning applications,” Geo-spatial Information Science, vol. 25, no. 1, pp. 14–33, Jan. 2, 2022. DOI: 10.1080/10095020.2 021.1917310.
M. A. Lombardi, “The use of GPS disciplined oscillators as primary frequency standards for calibration and metrology laboratories,” NIST, vol. 3, no. 3, pp. 56–65, Sep. 2008. DOI: 10.1080/19315775 .2008.11721437.
J. Bauer, C. Andrich, A. Ihlow, N. Beuster, and G. del Galdo, “Characterization of GPS disciplined oscillators using a laboratory GNSS simulation testbed,” in 2020 Joint Conference of the IEEE International Frequency Control Symposium and International Symposium on Applications of Ferroelectrics (IFCS-ISAF), Jul. 2020, pp. 1–4. DOI: 10.1109/IFCS-ISAF41089.2020.9234932.
F. Kunzi and O. Montenbruck, “Precise onboard time synchronization for LEO satellites,” NAVIGATION: Journal of the Institute of Navigation, vol. 69, no. 3, Sep. 21, 2022. DOI: 10.33012/navi.531.
F. S. Prol, R. M. Ferre, Z. Saleem, et al., “Position, navigation, and timing (PNT) through low earth orbit (LEO) satellites: A survey on current status, challenges, and opportunities,” IEEE Access, vol. 10, pp. 83 971–84 002, 2022. DOI: 10.1109/ACCESS.202 2.3194050.
K. Selvan, A. Siemuri, F. S. Prol, P. Välisuo, M. Z. H. Bhuiyan, and H. Kuusniemi, “Precise orbit determination of LEO satellites: A systematic review,” GPS Solutions, vol. 27, no. 4, p. 178, Aug. 1, 2023. DOI: 10.1007/s10291-023-01520-7.
L. Meng, J. Chen, J. Wang, and Y. Zhang, “Broadcast ephemerides for LEO augmentation satellites based on nonsingular elements,” GPS Solutions, vol. 25, no. 4, p. 129, Jul. 22, 2021. DOI: 10.1007/s10291-021-011 62-7.
A. Hussain, A. Ahmed, M. A. Shah, S. Katyara, L. Staszewski, and H. Magsi, “On mitigating the effects of multipath on GNSS using environmental context detection,” Applied Sciences, vol. 12, no. 23, p. 12 389, Jan. 2022. DOI: 10.3390/app122312389.
E. Gill, J. Morton, P. Axelrad, D. M. Akos, M. Centrella, and S. Speretta, “Overview of space-capable global navigation satellite systems receivers: Heritage, status and the trend towards miniaturization,” Sensors, vol. 23, no. 17, p. 7648, Jan. 2023. DOI: 10.3390/s23177648.
satsearch. “SpacePNT NaviLEO.” (), [Online]. Available: https://satsearch.co/products/spacepnt-navi leo (visited on 02/27/2025).
3GPP, TS 38.331, “radio resource control (RRC); protocol specification,”, version 18.4.0, 2025. [Online]. Available: https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?speci ficationId=3213 (visited on 02/21/2025).
A. V. Oppenheim, R. W. Schafer, and J. R. Buck, Discrete-time signal processing (2nd ed.) USA: Prentice-Hall, Inc., 1999, 870 pp., ISBN: 978-0-13-754920-7.
J. J. Spilker Jr., P. Axelrad, B. W. Parkinson, and P. Enge, Global Positioning System: Theory and Applications, Volume I, P. Axelrad, B. W. Parkinson, P. Enge, and J. J. S. Jr, Eds. American Institute of Aeronautics and Astronautics, 1996, ISBN: 978-1-56347-106-3.
H. L. V. Trees, Detection, Estimation, and Modulation Theory, Part I: Detection, Estimation, and Linear Modulation Theory. John Wiley & Sons, Mar. 24, 2004, 714 pp., ISBN: 978-0-471-46382-5.
S. M. Kay, Fundamentals of statistical signal processing (Volume I), in collab. with Internet Archive. Prentice-Hall PTR, 1993, 616 pp., ISBN: 978-0-13-345711-7.
J. A. del Peral-Rosado, J. A. López-Salcedo, G. Seco-Granados, F. Zanier, and M. Crisci, “Achievable localization accuracy of the positioning reference signal of 3gpp LTE,” in 2012 International Conference on Localization and GNSS, Jun. 2012, pp. 1–6. DOI: 10.1109/ICL-GNSS.2012.6253127.
3GPP, NR; physical channels and modulation, version 16.3.0, Oct. 2020. [Online]. Available: https://portal.3gpp.org/desktopmodules/Specifications/Sp ecificationDetails.aspx?specificationId=3213 (visited on 02/21/2025).
J. W. Betz and K. R. Kolodziejski, “Extended theory of early-late code tracking for a bandlimited GPS receiver,” NAVIGATION, vol. 47, no. 3, pp. 211–226, 2000. DOI: 10.1002/j.2161-4296.2000.tb00215.x.
J. W. Betz and K. R. Kolodziejski, “Generalized theory of code tracking with an early-late discriminator part i: Lower bound and coherent processing,” IEEE Transactions on Aerospace and Electronic Systems, vol. 45, no. 4, pp. 1538–1556, Oct. 2009. DOI: 10.1109/TAES.2009.5310316.
F. Soualle, M. Arizabaleta, C. Lichtenberger, et al., “New generation of PNT user terminals exploiting hybridization with LEO constellations,” presented at the Proceedings of the 37th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2024), Sep. 20, 2024, pp. 887–947. DOI: 10.33012/2024.19780.
F. Fabra, J. A. López-Salcedo, and G. Seco-Granados, “Analysis of baseband algorithms for LEO PNT,” Engineering Proceedings, vol. 54, no. 1, p. 36, 2023. DOI: 10.3390/ENC2023-15458.
H. Jiang and G. Gui, Channel Modeling in 5G Wireless Communication Systems (Wireless Networks). Springer Cham, 2020, ISBN: 978-3-030-32869-9.
3GPP, “Study on channel model for frequencies from 0.5 to 100 GHz,” 3GPP, Technical Report (TR) 38.901, 2017. [Online]. Available: https://www.etsi.org/deliver/etsi_tr/138900_138999/138901/16.01.00 _60/tr_138901v160100p.pdf (visited on 08/27/2025).
A. Zaidi, F. Athley, J. Medbo, U. Gustavsson, G. Durisi, and X. Chen, “Chapter 3 - propagation & channel modeling,” in 5G Physical Layer, A. Zaidi, F. Athley, J. Medbo, U. Gustavsson, G. Durisi, and X. Chen, Eds., Academic Press, pp. 35–85, ISBN: 978-0-12-814578-4.
A. Alayón Glazunov, A. Razavi, R. Maaskant, and J. Yang, “Semi-analytical model of the rician k-factor,” Radio Science, vol. 55, no. 11, e2020RS007099, 2020. DOI: 10.1029/2020RS007099.
Y. Lee and J. P. Choi, “Performance evaluation of high-frequency mobile satellite communications,” IEEE Access, vol. 7, pp. 49 077–49 087, 2019. DOI: 10.1109/ACCESS.2019.2909885.
V. M. Baeza, E. Lagunas, H. Al-Hraishawi, and S. Chatzinotas, “An overview of channel models for NGSO satellites,” in 2022 IEEE 96th Vehicular Technology Conference (VTC2022-Fall), Sep. 2022, pp. 1–6. DOI: 10.1109/VTC2022-Fall57202.2022.100 12693.
C. Amatetti, A. Vanelli-Coralli, M. Shast, et al., “Report on unified and data driven air-interface for 6g-NTN,” 6G-NTN, D4.1, Jul. 21, 2024.
B. Hofmann-Wellenhof, H. Lichtenegger, and J. Collins, Global Positioning System: Theory and Practice. Springer Science & Business Media, Dec. 6, 2012, 407 pp., ISBN: 978-3-7091-3297-5.
L. Marini-Pereira, L. F. D. Lourenço, J. Sousasantos, A. O. Moraes, and S. Pullen, “Regional ionospheric delay mapping for low-latitude environments,” Radio Science, vol. 55, no. 12, 2020. DOI: 10.1029/2020RS0 07158.
M. Imad, A. Grenier, X. Zhang, J. Nurmi, and E. S. Lohan, “Ionospheric error models for satellite-based navigation—paving the road towards LEO-PNT solutions,” Computers, vol. 13, no. 1, p. 4, Jan. 2024. DOI: 10.3390/computers13010004.
M. Irsigler, G. W. Hein, and A. Schmitz-Peiffer, “Use of c-band frequencies for satellite navigation: Benefits and drawbacks,” GPS Solutions, vol. 8, no. 3, pp. 119–139, Sep. 1, 2004. DOI: 10.1007/s10291-004 -0098-2.
Q. Liu, C. Gao, Z. Peng, R. Zhang, and R. Shang, “Smartphone positioning and accuracy analysis based on real-time regional ionospheric correction model,” Sensors, vol. 21, no. 11, p. 3879, Jan. 2021. DOI: 10 .3390/s21113879.
R. Radovanovic, “Adjustment of satellite-based ranging observations for precise positioning and deformation monitoring,” PhD Thesis, Jan. 1, 2002. [Online]. Available: http://hdl.handle.net/1880/42726.
B. Nava, P. Coïsson, and S. M. Radicella, “A new version of the NeQuick ionosphere electron density model,” Journal of Atmospheric and Solar-Terrestrial Physics, Ionospheric Effects and Telecommunications, vol. 70, no. 15, pp. 1856–1862, Dec. 1, 2008. DOI: 1 0.1016/j.jastp.2008.01.015.
Y. Yuan, N. Wang, Z. Li, and X. Huo, “The BeiDou global broadcast ionospheric delay correction model (BDGIM) and its preliminary performance evaluation results,” NAVIGATION: Journal of the Institute of Navigation, vol. 66, no. 1, pp. 55–69, Mar. 1, 2019. DOI: 10.1002/navi.292.
M. R. Imad, “Atmospheric effects on satellite navigation systems: Ionosphere and troposphere,” Ph.D. dissertation, 2024.
U. Ngayap, C. Paparini, M. Porretta, et al., “Comparison of NeQuick g and klobuchar model performances at single-frequency user level,” Engineering Proceedings, vol. 54, no. 1, p. 7, 2023. DOI: 10.3390/ENC2023-15475.
M. Mäkelä, “Comparison and development of ionospheric correction methods in GNSS,” Master thesis, Tampere University of Technology, 2016.
R. Orus, J. Parro, R. Prieto-Cerdeira, and R. Lucas, “NeQuickG performance: 2 year global results,” Boulder, CO, U.S, 2015. [Online]. Available: https://www.unoosa.org/pdf/icg/2015/icg10/wg/wgb07.pdf.
T. Hobiger and N. Jakowski, “Atmospheric signal propagation,” in Springer Handbook of Global Navigation Satellite Systems, P. J. Teunissen and O. Montenbruck, Eds., Cham: Springer International Publishing, 2017, pp. 165–193, ISBN: 978-3-319-42928-1.
P. Misra and P. Enge, Global Positioning System: Signals, Measurements, and Performance. Ganga-Jamuna Press, 2011, 569 pp., ISBN: 978-0-9709544-2-8.
J. Saastamoinen, “Atmospheric correction for the troposphere and stratosphere in radio ranging satellites,” in The Use of Artificial Satellites for Geodesy, American Geophysical Union (AGU), 1972, pp. 247–251, ISBN: 978-1-118-66364-6.
H. S. Hopfield, “Tropospheric effect on electromagnetically measured range: Prediction from surface weather data,” Radio Science, vol. 6, no. 3, pp. 357–367, 1971. DOI: 10.1029/RS006i003p00357.
J. A. Estefan and O. J. Sovers, “A comparative survey of current and proposed tropospheric refraction-delay models for DSN radio metric data calibration,” NASA-CR-197338, Oct. 1, 1994. [Online]. Available: https://ntrs.nasa.gov/api/citations/19950013586/downloads/19950013586.pdf (visited on 08/27/2025).
F. Dovis, B. Muhammad, E. Cianca, and K. Ali, “A run-time method based on observable data for the quality assessment of GNSS positioning solutions,” IEEE Journal on Selected Areas in Communications, vol. 33, no. 11, pp. 2357–2365, Nov. 2015. DOI: 10.1 109/JSAC.2015.2430513.
G. A. McGraw, “Tropospheric error modeling for high integrity airborne GNSS navigation,” in Proceedings of the 2012 IEEE/ION Position, Location and Navigation Symposium, Apr. 2012, pp. 158–166. DOI: 10.1109/PLANS.2012.6236877.
C.-S. Chen, Y.-J. Chiu, C.-T. Lee, and J.-M. Lin, “Calculation of weighted geometric dilution of precision,” Journal of Applied Mathematics, vol. 2013, no. 1, p. 953 048, 2013. DOI: 10.1155/2013/953048.
H. Sairo, D. Akopian, and J. Takala, “Weighted dilution of precision as quality measure in satellite positioning,” IEE Proceedings - Radar, Sonar and Navigation, vol. 150, no. 6, p. 430, 2003. DOI: 10 .1049/ip-rsn:20031008.
M. Kummu and O. Varis, “The world by latitudes: A global analysis of human population, development level and environment across the north–south axis over the past half century,” Applied Geography, vol. 31, no. 2, pp. 495–507, Apr. 1, 2011. DOI: 10.1016/j.apg eog.2010.10.009.
3GPP, Solutions for NR to support non-terrestrial networks (NTN), version 16.0.0, Dec. 2019. [Online]. Available: https://atisorg.s3.amazonaws.com/archive/3gpp-documents/Rel16/ATIS.3GPP.38.821.V1600.pdf (visited on 08/27/2025).
A. Gavras, H. Zaglauer, J. Pfeifle, et al., “Towards a space based infrastructure for 5g and beyond 5g networks,” in 2022 IEEE Globecom Workshops (GC Wkshps), Dec. 2022, pp. 1347–1352. DOI: 10.1109 /GCWkshps56602.2022.10008552.
Huawei and HiSilicon, “Discussion on performance evaluation for NTN,” 3GPP TSG RAN WG1 Meeting #99, Reno, USA, R1-1911858, Nov. 2019. [Online]. Available: https://www.3gpp.org/ftp/TSG_RAN/WG1_RL1/TSGR1_99/Docs/R1-1911858.zip (visited on 08/27/2025).
I. del Portillo, B. G. Cameron, and E. F. Crawley, “A technical comparison of three low earth orbit satellite constellation systems to provide global broadband,” Acta Astronautica, vol. 159, pp. 123–135, Jun. 1, 2019. DOI: 10.1016/j.actaastro.2019.03.040.
Thales, “Link budget results for NTN,” 3GPP TSG RAN WG1 Meeting #99, TDoc R1-1913351 R1-1913351, 2019. [Online]. Available: https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_99/Docs /R1-1913351.zip (visited on 08/27/2025).
3GPP, TS 38.214, “physical layer procedures for data,”, version 18.2.0, 2024. [Online]. Available: ht tps://www.etsi.org/deliver/etsi_ts/138200_138299/138214/18.02.00_60/ts_138214v180200p.pdf (visited on 02/21/2025).
O. K. Isik, J. Hong, I. Petrunin, and A. Tsourdos, “Integrity analysis for GPS-based navigation of UAVs in urban environment,” Robotics, vol. 9, no. 3, p. 66, Sep. 2020. DOI: 10.3390/robotics9030066.
M. Tahsin, S. Sultana, T. Reza, and M. Hossam-E-Haider, “Analysis of DOP and its preciseness in GNSS position estimation,” in 2015 International Conference on Electrical Engineering and Information Communication Technology (ICEEICT), May 2015, pp. 1–6. DOI: 10.1109/ICEEICT.2015.7307445.
J. Lesouple, T. Robert, M. Sahmoudi, J.-Y. Tourneret, and W. Vigneau, “Multipath mitigation for GNSS positioning in an urban environment using sparse estimation,” IEEE Transactions on Intelligent Transportation Systems, vol. 20, pp. 1316–1328, Apr. 1, 2019. DOI: 10.1109/TITS.2018.2848461.
Z. Zhang and L. Pan, “Current performance of open position service with almost fully deployed multi-GNSS constellations: GPS, GLONASS, galileo, BDS-2, and BDS-3,” Advances in Space Research, vol. 69, no. 5, pp. 1994–2019, Mar. 1, 2022. DOI: 10.1016/j.asr.2021.12.002.