Abstract
We address the problem of estimating the carrier-to-noise ratio (C/N0) in weak signal conditions. There are several environments, such as forested areas, indoor buildings and urban canyons, where high-sensitivity global navigation satellite system (HS-GNSS) receivers are expected to work under these reception conditions. The acquisition of weak signals from the satellites requires the use of post-detection integration (PDI) techniques to accumulate enough energy to detect them. However, due to the attenuation suffered by these signals, estimating their C/N0 becomes a challenge. Measurements of C/N0 are important in many applications of HS-GNSS receivers such as the determination of a detection threshold or the mitigation of near-far problems. For this reason, different techniques have been proposed in the literature to estimate the C/N0, but they only work properly in the high C/N0 region where the coherent integration is enough to acquire the satellites. We derive four C/N0 estimators that are specially designed for HS-GNSS snapshot receivers and only use the output of a PDI technique to perform the estimation. We consider four PDI techniques, namely non-coherent PDI, non-quadratic non-coherent PDI, differential PDI and truncated generalized PDI and we obtain the corresponding C/N0 estimator for each of them. Our performance analysis shows a significant advantage of the proposed estimators with respect to other C/N0 estimators available in the literature in terms of estimation accuracy and computational resources.
Similar content being viewed by others
References
Bhuiyan M, Söderholm S, Thombre S, Ruotsalainen L, Kirkko M, Kuusniemi H (2014) Performance evaluation of carrier-to-noise density ratio estimation techniques for BeiDou Bl signal. In: Proceeding of Ubiquitous Positioning Indoor Navigation and Location Based Service (UPINLBS), pp 19–25. https://doi.org/10.1109/UPINLBS.2014.7033706
Brown R, Hwang P (1997) Introduction to random signals and applied Kalman filtering: with MATLAB exercises and solutions. Wiley, New York
Bruggemann S, Greer D, Walker R (2006) Chip scale atomic clocks: Benefits to airborne GNSS navigation performance. In: Proceedings of international global navigation satellite systems society symposium, Holiday Inn, Surfers Paradise, Australia, 17–21 July 2006, pp 1–16
Corazza G, Pedone R (2007) Generalized and average likelihood ratio testing for post detection integration. IEEE Trans Commun 55(11):2159–2171. https://doi.org/10.1109/TCOMM.2007.908531
Elders H, Dettmar U (2004) Efficient differentially coherent code/Doppler acquisition of weak GPS signals. In: IEEE Proceedings of International Symposium on Spread Spectrum Techniques and Applications, pp 731–735. https://doi.org/10.1109/ISSSTA.2004.1371796
Falletti E, Pini M, Presti L (2011) Low complexity carrier-to-noise ratio estimators for GNSS digital receivers. IEEE Trans Aerosp Electron Syst 47(1):420–437. https://doi.org/10.1109/TAES.2011.5705684
Gaggero P, Borio D (2008) Ultra-stable oscillators: limits of GNSS coherent integration. In: Proceedings of ION GNSS 2008, Institute of Navigation, Savannah International Convention Center, Savannah, 16–19 September 2009 pp 565–575
Gómez D, López J, Seco G (2016) Generalized integration techniques for high-sensitivity GNSS receivers affected by oscillator phase noise. In: Proceedings of IEEE Statistical Signal Processing Workshop (SSP). Palma de Mallorca, pp 1–5. https://doi.org/10.1109/SSP.2016.7551809
Gómez D, López J, Seco G (2017) Optimal fractional non-coherent detector for high-sensitivity GNSS receivers robust against residual frequency offset and unknown bits. In: Proceedings of IEEE Workshop on Positioning, Navigation and Communications (WPNC). Bremen, pp 1–5. https://doi.org/10.1109/WPNC.2017.8250055
Groves P (2005) GPS Signal-to-noise measurement in weak signal and high-interference environments. Navigation 52(2):83–94
Kaplan E, Hegarty C (2005) Understanding GPS: principles and applications. Artech House, Norwood
Klobuchar J (1996) Global positioning system: theory and applications. American Institute of Aeronautics and Astronautics. Inc., Washington DC
Lopez J, Vicario J, Seco G (2008) Optimal noncoherent detector for HS-GNSS receivers. In: Proceedings of IEEE Signal Processing for Space Communications. Rhodes Island, pp 1–6. https://doi.org/10.1109/SPSC.2008.4686722
López G, Seco G (2005) CN0 estimation and near-far mitigation for GNSS indoor receivers. In: Proceedings of IEEE Vehicular Technology Conference. Stockholm, pp 2624–2628. https://doi.org/10.1109/VETECS.2005.1543810
Musumeci L, Dovis F, Silva P, Lopes H, Silva J (2014) Design of a very high sensitivity acquisition system for a space GNSS receiver. In: Proceedings of IEEE/ION PLANS. Hyatt Regency Hotel, Monterey, 5–8 May 2014, pp 556–568. https://doi.org/10.1109/PLANS.2014.6851417
Schmid A, Neubauer A (2005a) Carrier to noise power estimation for enhanced sensitivity Galileo/GPS receivers. In: Proceedings of IEEE Vehicular Technology Conference, vol 4. Stockholm, pp 2629–2633. https://doi.org/10.1109/VETECS.2005.1543811
Schmid A, Neubauer A (2005b) Differential correlation for Galileo/GPS receivers. In: Proceedings of IEEE International Conference on Acoustics, Speech, and Signal Processing. Philadelphia, pp 953–956. https://doi.org/10.1109/ICASSP.2005.1415869
Seco G, Lopez J, Jimenez D, Lopez G (2012) Challenges in indoor global navigation satellite systems: unveiling its core features in signal processing. IEEE Signal Process Mag 29(2):108–131. https://doi.org/10.1109/MSP.2011.943410
Strässle C, Megnet D, Mathis H, Bürgi C (2007) The squaring-loss paradox. In: Proceedings of ION GNSS 2007, Institute of Navigation, Fort Worth Convention Center, Fort Worth, 25–28 September 2007, pp 2715–2722
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Gómez-Casco, D., López-Salcedo, J.A. & Seco-Granados, G. C/N0 estimators for high-sensitivity snapshot GNSS receivers. GPS Solut 22, 122 (2018). https://doi.org/10.1007/s10291-018-0786-y
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s10291-018-0786-y